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Plant latex and other exudates as plant defense systems: Roles of various defense chemicals and proteins contained therein

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Abstract

Plant latex and other exudates are saps that are exuded from the points of plant damage caused either mechanically or by insect herbivory. Although many (ca. 10%) of plant species exude latex or exudates, and although the defensive roles of plant latex against herbivorous insects have long been suggested by several studies, the detailed roles and functions of various latex ingredients, proteins and chemicals, in anti-herbivore plant defenses have not been well documented despite the wide occurrence of latex in the plant kingdom. Recently, however, substantial progress has been made. Several latex proteins, including cysteine proteases and chitin-related proteins, have been shown to play important defensive roles against insect herbivory. In the mulberry (Morus spp.)-silkworm (Bombyx mori) interaction, an old and well-known model system of plant-insect interaction, plant latex and its ingredients--sugar-mimic alkaloids and defense protein MLX56--are found to play key roles. Complicated molecular interactions between Apocynaceae species and its specialist herbivores, in which cardenolides and defense proteins in latex play key roles, are becoming more and more evident. Emerging observations suggested that plant latex, analogous to animal venom, is a treasury of useful defense proteins and chemicals that has evolved through interspecific interactions. On the other hand, specialist herbivores developed sophisticated adaptations, either molecular, physiological, or behavioral, against latex-borne defenses. The existence of various adaptations in specialist herbivores itself is evidence that latex and its ingredients function as defenses at least against generalists. Here, we review molecular and structural mechanisms, ecological roles, and evolutionary aspects of plant latex as a general defense against insect herbivory and we discuss, from recent studies, the unique characteristics of latex-borne defense systems as transport systems of defense substances are discussed based on recent studies.

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... It also contains starch, sugars, oils, tannins, resins, sterols, fatty acids, resins, and gums that coagulate when exposed to air. A variety of enzymes and inhibitors, including thrombins, plasmins, papain, hevein, allergens, toxins, and lectins are present in latex [3]. Numerous functions, including the elimination of waste metabolites, protecting damaged tissue, fending off herbivores, and fending off infections are performed by the plant latex. ...
... Among the plant families, Euphorbiaceae is one of the most diverse and largest families of the angiosperms that contain maximum latex-producing species [12]. Since the interactions between plant and herbivorous insects are more intense in tropical regions than in temperate regions, the frequent occurrence of laticiferous plants is interrelated with the defensive roles of latex and laticifer against herbivores [3]. In fact, just 6% of temperate plant species produced latex, compared to 14% of tropical plant species. ...
... The most popular theories for the function of latex in plants include sealing injured tissues, excreting waste metabolites, protecting against herbivores, and fending off diseases [3]. There is a lot of evidence to support the defensive roles of latex against herbivores [9]. ...
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Over 350 million years have passed since the documentation of the first interaction between plants and insects. Numerous plant defense qualities and associated counter-adaptive features have developed as a result of these interactions between insects and plants. These characteristics might be either morphological or biological in nature. One of the most significant and useful biochemical characteristics in plants is latex. Latex has a sticky property due to presence of secondary metabolites in it, which aids in entangling or sealing the mouthparts of small insects. These metabolites also chemically interact with the insects interfering with crucial bodily processes. Plant latex has amazing properties that help protect plants from insects and inhibit them in general. It may be possible to control insect pests in a natural, secure, and long-lasting manner by correctly identifying plant latex with strong insecti-cidal properties and developing formulations of plant latex.
... Latex, also known as milk sap, is a cytoplasmic exudate of specialized living cells, called laticifers that synthesize and accumulate it (Konno et al., 2004;Konno, 2011). Not all latex has a milky appearance, although a sticky consistency is common. ...
... Not all latex has a milky appearance, although a sticky consistency is common. Latex contains inorganic ions and a variety of low and high molecular weight organic compounds, such as alkaloids, cardenolides, terpenoids, carbohydrates, amino acids, volatile compounds as well as various proteins and enzymes, such a-amylase and peptidase inhibitors, chitinases, glycosyl hydrolases and peptidases, which can act as defensive compounds against insects (Konno, 2011). Like resins, latex is also stored under pressure and is released in response to a mechanical damage to the laticifers. ...
... Plant saps are fluids transported in xylem cells or in phloem sieve tube elements, as described before. Despite their defensive roles (Zalucki et al., 2001;Agrawal and Konno, 2009;Konno, 2011;Dussourd, 2021), except for xylem saps, the other types of exudates represent important sources of nutrients as polysaccharides, proteins, sugars, organic acids, free amino acids and peptides. Many insect species have developed strategies to take advantage of these food sources, despite some large nutritional imbalances such as C/N and C/P ratios. ...
Chapter
The knowledge of diets and their chemical components demanding digestion is a prerequisite to understanding the evolution of insect midguts. The clade Insecta is a hyper-diverse group, and this diversity extends to an impressive number of different feeding habits. Therefore, we can only summarize some of the most conspicuous and representative types of diets used by insects in their natural environments. The diversity of chemical compounds found in these diets is also staggering. This makes insects excellent models for investigating the comparative physiology of digestion among animals. The following diets will be discussed: detritus, plant exudates, other plant material, animal flesh, blood, fungi, lichens, bacteria, and nectar. In this chapter, we will discuss some of the major types and chemical compositions of diets used by insects. Our focus will be on chemical constituents that require some special type of digestion or that offer some challenge that leads to adaptations in the insect digestive system.
... Latex is one of the most important and effective plant defenses against insect herbivores (Dussourd and Denno 1994;Dussourd 2003Dussourd , 2017Hagel et al. 2008;Konno 2011). Latex commonly contains rubber, making it a sticky, viscous physical defense, as well as other bioactive compounds that come together to produce a complex chemical defense (Konno, 2011). ...
... Latex is one of the most important and effective plant defenses against insect herbivores (Dussourd and Denno 1994;Dussourd 2003Dussourd , 2017Hagel et al. 2008;Konno 2011). Latex commonly contains rubber, making it a sticky, viscous physical defense, as well as other bioactive compounds that come together to produce a complex chemical defense (Konno, 2011). Latex and the related insect adaptations used to circumvent latex and effectively attack laticiferous plants are major components of plant-insect interactions in modern ecosystems (Agrawal and Konno 2009). ...
... Only about eight of 22 extant laticiferous families produce rubber in their latex (Hagel et al. 2008;Agrawal and Konno 2009;Konno 2011;Venkatachalam et al. 2013); all reports of fossil latex come from rubber-rich families (McCoy et al. 2022), suggesting that vulcanization of rubber may be the primary fossilization mechanism for latex. If further chemical analyses of other examples of fossil latex prove this to be the case, this would imply a major bias in the fossil record of latex, both towards plants with rubber-rich latex and also towards fossilization settings that allow for or even promote natural vulcanization. ...
Article
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The evolutionary history of latex, a widespread chemical defense against insect herbivores, is not fully understood, yet a more detailed understanding of the fossil record of latex could help answer important evolutionary questions. This is, however, hampered by the difficulty of recognizing fossil latex and our still incomplete comprehension of the processes preserving latex. The best-studied fossil latex comes from the middle Eocene Geiseltal lignites in Germany, where fibrous laticifer mats, called "monkeyhair," are preserved in the severely degraded remains of some ancient trees in the brown coals. Laticifers are specialized elongate cells that carry latex throughout the plant. In previous studies, researchers have hypothesized that these fossil laticifers are preserved through natural low temperature vulcanization of rubber within the latex. Here, we report the results of Raman spectroscopic study on Geiseltal laticifers to identify the vulcanization of natural rubber and on spatially associated carbonaceous material to test various Raman carbon geothermometers for their accuracy for low-thermal-maturity samples. Raman spectra of the fossil laticifers are virtually identical to that of rubber (cis-1,4-polyisoprene) with additional bands demonstrating sulfur vulcanization. Raman spectra from the surrounding lignite and existing Raman-based carbon thermometers, currently calibrated down to about 100°C, clearly indicate that these samples were never exposed to temperatures higher than the surrounding lignite. These results directly validate the previous hypothesis of fossilization through natural vulcanization. Moreover, this work demonstrates that Raman spectroscopy is a rapid, non-destructive method for reliably identifying and characterizing fossil latex and that further development and calibration of the carbon thermometer may allow quantitative temperature measurements for low-thermal-maturity carbonaceous material.
... Nonetheless, the history of the use of lattices in wound care management dates back centuries. Traditionally different parts of plants like bark, stem, leaves, and roots are used in wound care management and other interventions of the coagulation cascade [86]. In India, latex-producing plants widely used in ancient medicinal practices such as Ayurveda, Siddha, Homeopathy, Unani, and Folk are the majority of them are listed in the Date Base 'Foundation for Revitalization of Local Health Traditions (FRLHT) and Traditional Knowledge Digital Library (TKDL) created by Ministry of Ayurveda, Yoga, Naturopathy, Unani, Siddha and Homeopathy (AYUSH), Government of India. ...
... The advantage of the use of latex protease is that they act both on the initial phase and final phase of hemostasis, due to their pro-coagulatory and thrombin-like activity, and fibrinolytic activity respectively. In the initial phase, it acts as a hemostatic agent, whereas in the final phase, it acts against inflammation along with gelatinolytic and collagenolytic activities that contribute towards wound debridement [86]. They are simpler and cheaper to obtain and purify as well which is another major advantage [101]. ...
... Latex resides in the cytoplasm of laticifers which are typical cells with an elongated shape and distributed in leaves, stems and roots. Latex is composed by the laticifer vacuoles' content which form an emulsion comprising: gum, tannins, oils, sugars, proteins, alkaloids, starches and terpenoids [2,5,6]. If plants are mechanically injured, for example for insect bites or for ruptures caused by wind, latex comes out and solidified when exposed to air [6]. ...
... Latex is composed by the laticifer vacuoles' content which form an emulsion comprising: gum, tannins, oils, sugars, proteins, alkaloids, starches and terpenoids [2,5,6]. If plants are mechanically injured, for example for insect bites or for ruptures caused by wind, latex comes out and solidified when exposed to air [6]. ...
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Calotropis procera produces a latex used in traditional medicine because of its components which are found to be biologically active. The latex of C. procera has many benefits such as pain reduction, antimicrobial attitude and other precious attributes. Latex lysozyme (LL) is a particular protein contained in C. procera plant having a promising antibacterial property. The process applied for extraction implicated ammonium sulfate precipitation, water extraction, ion exchange and gel filtration column chromatography evidencing 14.4 kDa for LL as a molecular mass. LL after purification showed 397.18 U mg⁻¹ as specific activity (10.30 purification fold), and with 37.9% as a yield. In addition, the chemical and physical analyses showed that LL had its best realization when the pH was 5.5 at 50 °C. Moreover when metal ions such as Ca²⁺ and Mg²⁺ were incorporated the relative activity of the enzyme resulted ampliflied. When a purification was conducted with CM-Cellulose and Sephadex G-100 chromatography, LL revealed an antibacterial property versus both Escherichia coli (MICs 14 µg ml⁻¹) and Bacillus cereus (MICs 13 µg ml⁻¹). HR-TEM analysis displayed an antimicrobial potential of LL after its purification; that analysis showed the deterioration of the cell wall (external membrane of the cell) of both E. coli and B. cereus. Therefore, the LL obtained from C. procera maintains ability as an antibacterial enzyme applicable in various domains such as biotechnological and pharmaceutical industries. Graphical abstract
... Cardenolides, a type of steroid, are found in the latex of various Apocynaceae plants, including milkweeds (Asclepias spp.) and oleander (Nerium oleander), as well as the latex of a Moraceae species, Antiaris toxicaria, apparently arising from convergent evolution [69]. A cardenolide derivative, glucoevatromonoside, isolated from a Brazilian cultivar of the Woolly foxglove (Digitalis lanata), has been shown to inhibit replication of herpes simplex virus types 1 and 2 [12]. ...
... Although a proteomic analysis of lettuce latex found evidence of proteins from lettuce mosaic virus, mirafiori lettuce big-vein virus, lettuce big-vein virus, lettuce infectious yellows virus, lettuce ring necrosis virus, and lettuce necrotic yellows virus [39], it is remarkable that, so far, only five viruses, PMeV, PMeV2, a Mexican variant of PMeV (PMeV-Mx), papaya virus Q (PpVQ), and papaya sticky fruit associated virus (PSFaV), have been isolated from latex samples [80]. This suggests that viruses have their transmission to plants impaired by the physical and chemical barrier formed by latex coagulation upon insect feeding on plant tissues [69]. Alternatively, latex is either a hostile environment for viruses or this plant fluid has been neglected in the plant virus field. ...
Article
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At least 20,000 plant species produce latex, a capacity that appears to have evolved independently on numerous occasions. With a few exceptions, latex is stored under pressure in specialized cells known as laticifers and is exuded upon injury, leading to the assumption that it has a role in securing the plant after mechanical injury. In addition, a defensive effect against insect herbivores and fungal infections has been well established. Latex also appears to have effects on viruses, and laticifers are a hostile environment for virus colonization. Only one example of successful colonization has been reported: papaya meleira virus (PMeV) and papaya meleira virus 2 (PMeV2) in Carica papaya. In this review, a summary of studies that support both the pro- and anti-viral effects of plant latex compounds is provided. The latex components represent a promising natural source for the discovery of new pro- and anti-viral molecules in the fields of agriculture and medicine.
... Laticifer density was strongly affected by substrate water availability in a positive relationship, as we expected. The greater amount of laticifers in plants growing with more moisture would increase its function of protection against the attack of herbivores (Fahn, 1979(Fahn, , 1990Farrell et al., 1991;Konno, 2011) or sealing wounds (Konno, 2011), especially in tropical regions where there is greater herbivory pressure. On the other hand, with lower water availability there were fewer laticifers in the secondary phloem, and consequently less production of their secretion (d' Auzac et al., 1989;Fay et al., 1989). ...
... Laticifer density was strongly affected by substrate water availability in a positive relationship, as we expected. The greater amount of laticifers in plants growing with more moisture would increase its function of protection against the attack of herbivores (Fahn, 1979(Fahn, , 1990Farrell et al., 1991;Konno, 2011) or sealing wounds (Konno, 2011), especially in tropical regions where there is greater herbivory pressure. On the other hand, with lower water availability there were fewer laticifers in the secondary phloem, and consequently less production of their secretion (d' Auzac et al., 1989;Fay et al., 1989). ...
... Lettuce, a widely cultivated leafy vegetable from the Asteraceae family (Kim et al. 2004), is also a source of two specialized metabolites: NR, and sesquiterpene lactones (STLs), a class of fifteen-carbon isoprenoids with a characteristic α-methylene γ-lactone moiety (Konno 2011). Lactuca serriola L., an herbaceous plant native to the Eastern Anatolia Region, and L. sativa L. (lettuce) both synthesize high molecular weight NR, especially during bolting, similar to H. brasiliensis. ...
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Natural rubber is a valuable and nonfungible raw material that has numerous applications in various industries. Its biosynthesis occurs in the laticiferous vessels of plants that produce natural rubber, which is of great interest for biotechnology. This review covers the rubber-producing plants and the biosynthetic pathways and genes influencing rubber quality and quantity. It also summarizes the recent progress in applying genome editing techniques to these plants, with an emphasis on Hevea brasiliensis, Taraxacum kok-saghyz, Parthenium argentatum, Eucommia ulmoides and Lactuca species. Genome editing technologies, especially CRISPR/Cas9, have provided unprecedented precision, efficiency and specificity for genetic manipulation. CRISPR-based genome editing has been proposed to enhance rubber quantity and quality in these plants. This review evaluates the recent research developments in the use of genome editing to enhance traits such as disease resistance, latex production and tree growth in rubber-producing plants. Furthermore, it discusses the current challenges and future prospects of genome editing for these plants and its potential impact on the rubber industry. This review provides a comprehensive overview of the state-of-the-art in genome editing for rubber-producing plants and highlights the promising opportunities for further research and innovation in this field.
... Indeed, latex forms a barrier against pathogen invasion due to its sticky and coagulating properties, limiting pathogen movements. Despite the variability of latex components, some chemical species can be distinguished, such as rubber, terpenoids, alkaloids, cardenolides, carotenoids, carbohydrates, phenolics, furanocoumarins, various metal ions, and proteins [46]. Some of them are toxic and/or dissuasive components depending on the plant species concerned. ...
Article
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Since biochemists and biologists have progressed in understanding the mechanisms involved in living organisms, biological systems have become a source of inspiration for chemists. In this context, the concept of colloidal tectonics, describing the spontaneous formation of colloidal particles or supracolloidal structures in which the building blocks are called “tectons”, has emerged. Therefore, a bottom-up edification of tectons towards (supra) colloidal structures is allowed. Each (supra) colloidal system has at least one of the following properties: amphiphilicity, predictability, versatility, commutability, and reversibility. However, for these systems to perform even more interesting functions, it is necessary for tectons to have very precise chemical and physical properties so that new properties emerge in (supra) colloidal systems. In this way, colloidal tectonics enables engineering at the nano- and micrometric level and contributes to the development of smart bioinspired systems with applications in catalysis, drug delivery, etc. In this review, an overview of the concept of colloidal tectonics is illustrated by some biotic systems. The design of abiotic (supra) colloidal systems and their applications in various fields are also addressed (notably Pickering emulsions for catalysis or drug delivery). Finally, theoretical directions for the design of novel self-assembled (supra) colloidal systems are discussed.
... Latex, an antifeedant primarily found in plants, is a potent deterrent among the many defences against herbivores that plants produce (Dillon and Dillon, 2004). The latex of various Ficus species contains several proteins, such as oxidases, protease inhibitors, chitinases, and cysteine protease, which are crucial in defending against herbivores (Konno, 2011). Cysteine proteases such as ficin and bromelain, abundant in the latex of Ficus, exhibit toxicity against herbivores, contributing to the plant's defence mechanism against insects (Konno et al., 2004). ...
Article
The diversity and health of insects that feed on plants are closely related to their mutualistic symbionts and host plants. These symbiotic partners significantly influence various metabolic activities in these insects. However, the symbiotic bacterial community of toxic plant feeders still needs further characterisation. This study aims to unravel bacterial communities associated with the different species of insect representing three insect orders: Thysanoptera, Hemiptera, and Lepidoptera, along with their predicted functional role, which exclusively feeds on latex-rich plant species Ficus microcarpa . By using 16S rRNA gene high-throughput sequencing, the analysis was able to define the major alignment of the bacterial population, primarily comprising Proteobacteria , Firmicutes , Bacteroidota , Actinobacteriota , and Acidobacteriota . Significant differences in symbiotic organisms between three insect groups were discovered by the study: hemipterans had Burkholderia and Buchnera , and lepidopterans had Acinetobacter . At the same time, Pseudomonas was detected in high abundance in both lepidopteran and thysanopteran insects. Furthermore, these symbionts exhibit consistent core functions, potentially explaining how different insects can consume the same host plant. The identified core functions of symbionts open avenues for innovative approaches in utilising these relationships to develop environment-friendly solutions for pest control, with broader implications for agriculture and environmental conservation.
... Over many decades of NR production, ET has been the most effective and commonly used enhancer of latex yield, but the adverse effects of ET should not be ignored, including tapping panel dryness (Osborne and Sargent, 1974). Like other latex-producing plants, the NR of the rubber tree is synthesized and stored in a specialized cellular organelle called the laticifer, which contributes to the defense strategy of plants (Konno, 2011;Hua et al., 2017). In laticifers, Expression profiles and Pearson correlation analysis of DEGs and DAMs relevant to amino-acid biosynthesis. ...
Article
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Hevea brasiliensis is an important cash crop with the product named natural rubber (NR) for markets. Ethylene (ET) is the most effective yield stimulant in NR production but the molecular mechanism remains incomplete. Here, latex properties analysis, transcriptome analysis, and metabolic profiling were performed to investigate the mechanism of NR yield increase in four consecutive tappings after ET stimulation. The results revealed that sucrose and inorganic phosphate content correlated positively with dry-rubber yield and were induced upon ET stimulation. Stimulation with ET also led to significant changes in gene expression and metabolite content. Genes involved in phytohormone biosynthesis and general signal transduction as well as 51 transcription factors potentially involved in the ET response were also identified. Additionally, KEGG annotation of differentially accumulated metabolites suggested that metabolites involved in secondary metabolites, amino-acid biosynthesis, ABC transporters, and galactose metabolism were accumulated in response to ET. Integrative analysis of the data collected by transcriptomics and metabolomics identified those differentially expressed genes and differentially accumulated metabolites are mainly involved in amino-acid biosynthesis and carbohydrate metabolism. Correlation analysis of genes and metabolites showed a strong correlation between amino-acid biosynthesis during ET stimulation. These findings provide new insights into the molecular mechanism underlying the ET-induced increase in rubber yield and further our understanding of the regulatory mechanism of ethylene signaling in rubber biosynthesis.
... Our additional anatomical examination of R. ornata flowers revealed that large laticifers are located within the midpetaline bands, but not in the thin, delicate areas of the corolla limb (Additional file 2: Fig. S4). Latex produced by laticifers in convolvulaceous plants is known for its role in defense against herbivores [68,69], suggesting that it might be unpalatable to katydids, which could explain why they only consumed the delicate areas of the corolla limb. This defense strategy exhibited by R. ornata aligns with the optimal defense hypothesis, which predicts that plants allocate more defense to tissues that strongly affect plant fitness [22,27,28]. ...
Article
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Background Rivea ornata, a rare species from the morning glory family, exhibits uncommon characteristics compared to other typical morning glories, including nocturnal flowers that fit the classic moth pollination syndrome. However, the accuracy of its predicted pollination syndrome and its mating system have never been assessed. Additionally, R. ornata flowers attract not only pollinators but also florivores, potentially reducing plant reproductive success. Therefore, this study examined two populations of R. ornata in Thailand and assessed traits related to pollinator attraction and reward, determined its mating system, identified floral visitors and effective pollinators, and investigated the effect of florivory on reproductive success. Results Rivea ornata is highly fertile but self-incompatible and an obligate outcrosser, rendering it highly dependent on pollinators. Lepidopterans, particularly nocturnal hawk moths, were found to account for a significant proportion of all visits and were the sole effective pollinators of this plant species, in correspondence with its predicted pollination syndrome. Surprisingly, florivory did not significantly reduce reproductive success. This phenomenon may be explained by the strategies employed by R. ornata, which align with the optimal defense hypothesis and functional trade-offs. Specifically, R. ornata appears to invest resources in defending key floral structures while, simultaneously, guard ants are conspicuously absent from flowers, resulting in some florivore damage to non-vital floral organs but ensuring that pollinators are not deterred by ants and thus maintaining high pollinator visitation rates. Conclusions Our findings indicate that reproduction-related traits in R. ornata, including those involved in pollinator attraction and reward and florivore defense, are highly effective and work in concert to maximize plant reproductive success. Therefore, a main risk that R. ornata faces is the decline or disappearance of hawk moths and other lepidopterans given its extreme specialization and high dependence on pollinators, and conservation efforts should include habitat protection for both R. ornata and its pollinators. Supplementary Information The online version contains supplementary material available at 10.1186/s12862-024-02301-7.
... 51,52 The viscosity and stickiness of latex give it properties to trap insects and seal wounds to prevent the entry of pathogens, suggesting the role of latex as a defense mechanism in these plants. 8,53 In agreement with the role of jasmonic acid in the defense of plants 52 and the manipulation of H. brasiliensis trees with exogenous applications of JA that have shown alterations in protein production. 54-56 ...
Article
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The rubber tree Hevea brasiliensis (Willd. Ex Adr. De Juss.) Müell Arg.] is an important source of latex for the production natural rubber. Natural rubber is an important biopolymer used in various industries, but aspects related to hormonal regulation in biosynthesis are still unknown, which would allow optimizing its production. We review the molecular and physiological mechanisms of increases latex regeneration and flow by the stimulation of rubber trees with exogenous applications of ethylene and jasmonate. We found that the increase in latex regeneration by ethylene is due to the increase in gene level expression and enzymatic activity of key photosynthesis and glycolysis enzymes for the generation of precursors in the first phase of rubber biosynthesis. Latex flow is supported by up-regulated genes in sucrose metabolism such as invertases, induction of sucrose transporters (SUT), and aquaporins (PIP) to maintain flow and turgor pressure in laticifers. Meanwhile, the increase in latex yield mediated by jasmonate may be due to the induction of laticifer differentiation in the long term and in the short term be mediated by the induction of small rubber particles (SRPP) as non-enzymatic cofactors in the production of latex. This information contributes to the knowledge of latex biosynthesis, which allows for a greater support for the exogenous application of jasmonates and ethylene to regulate its production.
... In fact, the two forbs significantly associated with fertilized plots in our study have traits that may provide protection against herbivory: C. racemosa is a spiny species and T. barbata has latex. Spinescence is a trait typically associated with vertebrate herbivory (Pérez-Harguindeguy et al., 2013), and latex is a sap exuded from damaged plant tissues, in response to either vertebrate or insect herbivory (Konno, 2011). This suggests that grazing may have had, at least, some influence on our results (Laliberté and Tylianakis, 2012;Segre et al., 2016). ...
Article
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Nitrogen pollution has increased dramatically over the last decades, becoming a major contributor to biodiversity loss and compositional changes globally. While the main effects of excessive nutrients on plant communities are well established, Mediterranean grasslands have been less studied despite their high levels of biodiversity. Moreover, evidence has shown that the impacts of nutrients may depend on additional factors, namely soil conditions and grazing, increasing the uncertainty about the effects of increasing nutrient availability in these systems. In this work, we assessed the short-term effects (1 year) of fertilization in an extensively grazed oak open woodland (called montado, or dehesa), in Spain. Plots comprised a complete randomized design with four treatments: control (not fertilized), fertilization with nitrogen at a rate of 100 kg N ha − 1 , fertilization with phosphorous (50 kg P ha − 1) and fertilization with both N and P (100 kg ha − 1 N + 50 kg ha − 1 P). We assessed changes in plant species composition and functional diversity and evaluated the association between species and fertilization treatments with an indicator species analysis. Our results showed that species diversity increased with NP fertilization and that forbs in particular increased in cover and richness. SLA and seed mass also showed differences compared to the control. The Community-weighted mean and functional dispersion of groups based on growth form and N-fixing ability were not influenced by fertilization. Two species were significantly associated with fertilized plots: the spiny forb Carlina racemosa and the latex-producing forb Tolpis barbata. Our study suggests that short-term fertilization may alleviate nutrient limitations in these systems, increasing plant diversity , although longer-term studies are needed to understand the effects of a continuous increase in nutrient availability.
... After treatment with rust fungus, the number of components decreased to 45 (without formic acid treatment). These results are consistent with the findings of Delaney KJ et al. [7][8][9]19], who discovered the induction of phenolic compound synthesis after treating plants with jasmonic acid. We have also shown that the addition of formic acid to the eluent and the treatment of the TBME extract improved the quality of chromatographic separation (compare Figures 4 and 9, Table 4). ...
Chapter
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The disease resistance of wheat cultivars varies due to the plants’ defense systems, which include signaling molecules such as ferulic (coniferelic) acid, salicylic, arachidonic, and jasmonic acids. Therefore, the determination of quantitative and qualitative composition of signal molecules, low-molecular organic compounds, and proteins in wheat varieties with different leaf rust disease resistance levels is crucial. In this study, proteins and signal molecules in wheat leaf samples inoculated with fungal pathogen were isolated and identified using LCMS and HPLC chromatography. In addition, changes in the concentration of several organic compounds in infected plants were analyzed. The validity of obtained data on the absence of other components of metabolic cycles after chromatographic separation was discussed.
... Latex contains a variety of secondary metabolites and defense chemicals such as chitin-bonding proteins, alkaloids, terpenoids, furanocoumarins, sugar, rubber, starch, phenolics, oils, enzymes (glucosidases, proteases, and chitinases), cardenolides, etc. It has a role in defense against pathogens and herbivores, covering damaged tissues and the excretion of waste metabolites [84]. After exudation, latex acts as a physical barrier because it rapidly coagulates on exposure to oxygen [85]. ...
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Wound-induced xylem occlusion significantly affects the vase life of cut flowers, as oxidative stress and the polymerization of phenolic compounds lead to the deposition of phenolic compounds/secondary metabolites in the stem ends of cut flowers to heal open tissues of freshly cut stems and prevent microbial invasion. However, this deposition causes blockage of vessels, reduced water uptake, and shortened vase life. The physiological plugging of vessels is linked with various oxidative enzymes’ (PAL, PPOs, LACs, and COs) actions taken to increase the synthesis of different compounds, e.g., lignin, suberin, tyloses, gel, and latex, in wounded areas. The use of chemical preservatives/enzyme inhibitors is one of the safest and most efficient techniques employed to minimize vascular blockage and inhibit phenolic compounds deposition and exudation. This review mainly discusses the types of oxidative enzymes, their pathways and biochemistry along with production of secondary metabolites, their biosynthesis, and their modes of action involved in vascular blockage. It also summarizes the different types of preservatives used in postharvest treatments to improve relative water uptake, flower fresh weight, petal protein content, and hydraulic conductance and prolong the vase life of cut flowers during storage. It is hoped that this elaborate study will help researchers in designing new studies concerning occlusion caused by the accumulation of phenolic compounds in vessels.
... Upon mechanical injury, roughly 9% of all angiosperm plants exude latex, which often contains toxins and functions as a chemical and physical barrier against insect herbivores by poisoning them or gumming up their mouthparts [1][2][3][4][5]. Before taking up food, many plant-feeding insects therefore sabotage the latex-containing elongated cells (laticifers) running along the leaf veins and cut off leaf veins or petioles with their mandibles to drain the feeding site and to circumvent exposure to latex. ...
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Sabotaging milkweed by monarch caterpillars (Danaus plexippus) is a famous textbook example of disarming plant defence. By severing leaf veins, monarchs are thought to prevent the flow of toxic latex to their feeding site. Here, we show that sabotaging by monarch caterpillars is not only an avoidance strategy. While young caterpillars appear to avoid latex, late-instar caterpillars actively ingest exuding latex, presumably to increase sequestration of cardenolides used for defence against predators. Comparisons with caterpillars of the related but non-sequestering common crow butterfly (Euploea core) revealed three lines of evidence supporting our hypothesis. First, monarch caterpillars sabotage inconsistently and therefore the behaviour is not obligatory to feed on milkweed, whereas sabotaging precedes each feeding event in Euploea caterpillars. Second, monarch caterpillars shift their behaviour from latex avoidance in younger to eager drinking in later stages, whereas Euploea caterpillars consistently avoid latex and spit it out during sabotaging. Third, monarchs reared on detached leaves without latex sequestered more cardenolides when caterpillars imbibed latex offered with a pipette. Thus, we conclude that monarch caterpillars have transformed the ancestral ‘sabotage to avoid’ strategy into a ‘sabotage to consume’ strategy, implying a novel behavioural adaptation to increase sequestration of cardenolides for defence.
... The synthesis of natural rubber in plants is a complex process. In some plants, rubber is thought to be mainly converted from sugar produced by plant photosynthesis [42,43] and beneficial to plant defense mechanisms [44,45]. The rubber content in the three places averages around 6 %. ...
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Taraxacum kok-saghyz (TKS) latex is a natural latex produced from its root, and its extraction optimization process is mainly studied in the present paper. The composition of fresh roots of TKS was quantitatively analyzed, and the results showed that the moisture content of the fresh root was approximately 70 %, and the rubber content averaged to 6 % (dry weight ratio). An optimal process route for extracting the TKS latex was finally determined, making the extraction efficiency reach about 80 %, and a new latex extraction process was established and optimized and named “the process of Buffer Extraction TKS Latex (BETL)”. Hevea latex, extracted TKS latex and TKS latex collected directly from the broken roots were compared for study. The results showed that, like Hevea latex, the appearance of TKS latex was milky white; and after centrifugation, both showed four layers from top to bottom: rubber particles, Frey-Wyssling particles, C-serum and lutoids. The results of the composition analysis showed that the concentration of TKS latex ranged from 54.54 % to 68.25 %, which is close to that of concentrated Hevea latex; the moisture content of TKS latex was between 31.75 % and 45.46 %. The protein content of TKS latex was 13.51 mg/mL, which was lower than that of Hevea latex at the same rubber hydrocarbon concentration. The molecular structures and properties of Hevea latex, the extracted TKS latex, and the collected TKS latex were characterized by FTIR, ¹³C NMR, GPC, TG, SEM and LPSA, and the results showed that the main components and structure of the three latexes were similar, which are all cis-1,4-polyisoprene, and include the proteins and lipids. The distributions molecular weights of the three latexes all showed a bimodal distribution, but the molecular weight of the latex collected from TKS was lower, which indicates the larger molecules were difficult to flow outside the root automatically. The Hevea latex and TKS latex rubber particles were both core-shell structure and the size distribution were bimodal, which was consistent with the GPC analysis results.
... Latex was found to contain a broad range of specialized metabolites, different from those found in the corresponding plants, such as terpenoids, cardenolides, cerebrosides, alkaloids, and phenolics [8-10], which are partly responsible for their antibacterial, antifungal, anthelmintic, cytotoxic, and insectrepellent activities [11]. Latexes have also been recognized as reservoirs of defense-related proteins [7,12]. ...
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Euphorbia seguieriana ssp. seguieriana Necker (ES) and Euphorbia cyparissias (EC) with a habitat in the Deliblato Sands were the subject of this examination. The latexes of these so far insufficiently investigated species of the Euphorbia genus are used in traditional medicine for the treatment of wounds and warts on the skin. To determine their chemical composition, non-targeted screening of the latexes’ chloroform extracts was performed using liquid chromatography coupled with quadrupole time-of-flight mass spectrometry employing an electrospray ionization source (LC-ESI QTOF MS). The analysis of the obtained results showed that the latexes of ES and EC represent rich sources of diterpenes, tentatively identified as jatrophanes, ingenanes, tiglianes, myrsinanes, premyrsinanes, and others. Examination of the anticancer activity of the ES and EC latex extracts showed that both extracts significantly inhibited the growth of the non-small cell lung carcinoma NCI-H460 and glioblastoma U87 cell lines as well as of their corresponding multi-drug resistant (MDR) cell lines, NCI-H460/R and U87-TxR. The obtained results also revealed that the ES and EC extracts inhibited the function of P-glycoprotein (P-gp) in MDR cancer cells, whose overexpression is one of the main mechanisms underlying MDR.
... Due to the chemical diversity that distinguishes latex from other plant secretions, it has different biological and pharmacological activities. Popularly, latex has been used in the treatment of many ailments (Konno, 2011;Salomé Abarca et al., 2019;Castelblanque et al., 2020). As an anti-inflammatory, anti-diarrheal (Roy et al., 2005;Hua et al., 2015). ...
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This study aimed to evaluate the dry crude latex extract from P. tomentosa, endemic to the Sahara, by determining the total content of polyphenols and flavonoids, and detecting the plant compounds by HPLC chromatography. Also, Antioxidant activity was measured through three tests: (BCB) beta-carotene/linoleic acid bleaching assay, (DPPH) radical scavenging and (FRAP) ferric reducing ability assay. In addition, anti-inflammatory activity. The results showed that the dry crude latex extract of P. tomentosa showed moderate content of polyphenols and flavonoids in the dry crude latex extract of P. tomentosa. Besides, qualitative HPLC analysis led to the detection of a group of phenolic compounds of this extract that have therapeutic properties. Also, the studied extract had strong activity in the beta-carotene/linoleic acid bleaching test and the values obtained were very close to the reference gallic acid. The results also indicated significant antioxidant activities in the DPPH and FRAP assay compared to ascorbic acid. In addition, the strong effect of dry crude latex extract from P. tomentosa in inhibiting protein denaturation induced by albumin hyperthermia, compared to ASPEGIC®, which is used as a reference drug in infections. In conclusion, the results indicate that the dry crude latex extract of P. tomentosa has antioxidant and anti-inflammatory activity, which confirms the use of this extract in folk medicine, which could be a first step in introducing it into therapeutic applications.
... Due to the chemical diversity that distinguishes latex from other plant secretions, it has different biological and pharmacological activities. Popularly, latex has been used in the treatment of many ailments (Konno, 2011;Salomé Abarca et al., 2019;Castelblanque et al., 2020). As an anti-inflammatory, anti-diarrheal (Roy et al., 2005;Hua et al., 2015). ...
Article
Full-text available
This study aimed to evaluate the dry crude latex extract from P. tomentosa, endemic to the Sahara, by determining the total content of polyphenols and flavonoids, and detecting the plant compounds by HPLCchromatography. Also, Antioxidant activity was measured through three tests: (BCB) beta-carotene/linoleic acid bleaching assay, (DPPH) radical scavenging and (FRAP) ferric reducing ability assay. In addition, anti-inflammatory activity. The results showed that the dry crude latex extract of P. tomentosa showed moderate content of polyphenols and flavonoids in the dry crude latex extract of P. tomentosa. Besides, qualitative HPLC analysis led to the detection of a group of phenolic compounds of this extract that have therapeutic properties. Also, the studied extract had strong activity in the beta-carotene/linoleic acid bleaching test and the values obtained were very close to the reference gallic acid. The results also indicated significant antioxidant activities in the DPPH and FRAP assay compared to ascorbic acid. In addition, the strong effect of dry crude latex extract from P. tomentosa in inhibiting protein denaturation induced by albumin hyperthermia, compared to ASPEGIC®, which is used as a reference drug in infections. In conclusion, the results indicate that the dry crude latex extract of P. tomentosa has antioxidant and anti-inflammatory activity, which confirms the use of this extract in folk medicine, which could be a first step in introducing it into therapeutic applications
... The latex of the Euphorbia species can be distinguished from the latexes of different species using microscopy. The latex was examined using a compound microscope, and the pattern of the starch grain was discovered to be the most distinguishing feature (Konno, 2011). Euphorbia tirucalli and E. neriifolia grains were found to be oval or dumb-bell-shaped, whereas E. antiquorum grains were amoeba-shaped. ...
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Euphorbia neriifolia (EN) is a medicinal plant used to treat a variety of ailments in traditional systems. Despite numerous studies on pharmacological activities, no information was available on the microscopic study of this plant. This is the first study that has been attempted to fill this need by performing the light and field emission scanning electron microscopy (FESEM) of leaf, stem, and latex. The powder microscopy of several organs (leaves, stem, and bark) and exudate (latex) of EN was carried out using safranine, fast green, phloroglucinol, and other standard solutions at different magnifications. The chemical fingerprinting of petroleum ether extract was accomplished by using thin layer chromatography. The optimization of total lipid content from the EN leaf under ultrasound‐assisted extraction (UAE) and soxhlet extraction (SE) procedure was determined using response surface methodology (RSM). The studied factors that affect the lipid content were: solvent ratio, extraction temperature, and extraction time. Several notable characteristics observed in the leaf of EN are amphistomatic leaves with anticlinical cell walls, anomocytic stomata, spongy mesophyll cells, elongated palisade cells, angular collenchyma, and U‐shaped vascular bundle. The plano‐convex midrib is covered by polygonal to oval‐shaped cuticles and contains anomocytic stomata. The circular petiole has no trichomes and contains laticifers, crystals, and idioblasts. The circular stem was observed with trichomes, hypodermis, collenchyma, parenchymatous cells, central pith, pentagonal stellar region, cambium, and 2–4 times more xylem that of phloem. All of the powdered plant parts and exudate under study contained trichomes, xylem vessels, wood fibers, cork cells, starch grains, calcium oxalate crystals, idioblasts, lignified cork, tannin content, stone cells, and oil globules. The blackish‐green colored petroleum ether extract with semi‐solid consistency showed the greatest percent (%) yield of 4% in the latex of EN. The thin layer chromatography (TLC) examination of petroleum ether extract of EN leaf produced a maximum 6 spots with R f values of 0.16, 0.58, 0.62, 0.73, and 0.96 in the mobile phase of petroleum ether‐acetone (8:2). In terms of optimization, the dark green colored UAE extract with semi‐sticky consistency showed highest % yield of 4.5% whereas the yellowish green colored SE extract of sticky consistency showed the highest % yield of 4.9%. The findings showed that there were not many differences in the total lipid content between UAE (0.16%) and SE (0.11%). However, the best optimum condition for lipid content extraction analysis was obtained as follows: solvent ratio (PE:HE) 50:50, extraction temperature 50°C, extraction time 45 min for UAE, and solvent ratio (PE:HE) 60:40, extraction temperature 45°C, and extraction time of 24 h for SE. Hence, this study signifies the various noteworthy microscopic features along with the presence of different phytocompounds through TLC and best optimized condition for the extraction of lipids from different parts of EN. As no previous study has been reported, the outcomes obtained from the current study prove to be beneficial in the identification of species, quality control, and detection of any adulteration from the laboratory and commercial samples of EN. Research Highlights The percent yield was found to be maximum in latex extract (4%). The leaf pet ether extract was separated into 6 bands with different R f values. The extracted compounds from Euphorbia neriifolia leaves were categorized into non‐polar heat tolerant. The highest total lipid yield (0.1119) was obtained at solvent ratios 60:40 of PE:HE (petroleum ether: petroleum hexane).
... The milky sap, produced by laticifers, contains a broad range of biologically active molecules that hold potential medicinal applications. Plant latex extracts have been found to contain numerous proteins and low molecular weight compounds, including alkaloids, carotenoids, phenols and terpenoids, among others [22][23][24][25][26]. Alkaloids, which are nitrogencontaining organic molecules, form the largest group of components within latex and are responsible for the plant's defense against herbivores and pathogens. ...
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Herbal medicines were widely used in ancient and modern societies as remedies for human ailments. Notably, the Papaveraceae family includes well-known species, such as Papaver somniferum and Chelidonium majus, which possess medicinal properties due to their latex content. Latex-bearing plants are a rich source of diverse bioactive compounds, with applications ranging from narcotics to analgesics and relaxants. With the advent of high-throughput technologies and advancements in sequencing tools, an opportunity exists to bridge the knowledge gap between the genetic information of herbs and the regulatory networks underlying their medicinal activities. This emerging discipline, known as herbgenomics, combines genomic information with other -omics studies to unravel the genetic foundations, including essential gene functions and secondary metabolite biosynthesis pathways. Furthermore, exploring the genomes of various medicinal plants enables the utilization of modern genetic manipulation techniques, such as Clustered Regularly-Interspaced Short Palindromic Repeats (CRISPR/Cas9) or RNA interference. This technological revolution has facilitated systematic studies of model herbs, targeted breeding of medicinal plants, the establishment of gene banks and the adoption of synthetic biology approaches. In this article, we provide a comprehensive overview of the recent advances in genomic, transcriptomic, proteomic and metabolomic research on species within the Papaveraceae family. Additionally, it briefly explores the potential applications and key opportunities offered by the -omics perspective in the pharmaceutical industry and the agrobiotechnology field.
... To find antifungal β-1,3-glucanase, we searched in plant latex, a known biological defense system. Plant latex, the cytosol of special cells called laticifers, is generally considered to play a protective role against herbivores and insects (Konno 2011), and we have presented evidence to suggest that latex also plays a role in the defense against fungal pathogens (Kitajima et al. 2018). In comparison with other tissues, plant latex is enriched in defense-related proteins (Chye and Cheung 1995;Konno et al. 2004). ...
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Main conclusion Each β-1,3-glucanase with antifungal activity or yeast lytic activity hydrolyzes different structures of β-1,3-glucans in the fungal cell wall, respectively. Abstract Plants express several glycoside hydrolases that target chitin and β-glucan in fungal cell walls and inhibit pathogenic fungal infection. An antifungal β-1,3-glucanase was purified from gazyumaru (Ficus microcarpa) latex, designated as GlxGluA, and the corresponding gene was cloned and expressed in Escherichia coli. The sequence shows that GlxGluA belongs to glycoside hydrolase family 17 (GH17). To investigate how GlxGluA acts to degrade fungal cell wall β-glucan, it was compared with β-1,3-glucanase with different substrate specificities. We obtained recombinant β-1,3-glucanase (designated as CcGluA), which belongs to GH64, from the bacterium Cellulosimicrobium cellulans. GlxGluA inhibited the growth of the filamentous fungus Trichoderma viride but was unable to lyse the yeast Saccharomyces cerevisiae. In contrast, CcGluA lysed yeast cells but had a negligible inhibitory effect on the growth of filamentous fungi. GlxGluA degraded the cell wall of T. viride better than CcGluA, whereas CcGluA degraded the cell wall of S. cerevisiae more efficiently than GlxGluA. These results suggest that the target substrates in fungal cell walls differ between GlxGluA (GH17 class I β-1,3-glucanase) and CcGluA (GH64 β-1,3-glucanase).
... The latex secreted by specialized cells (laticifers) serves as a rich resource of various beneficial secondary metabolites such as alkaloids, terpenoids, glycosides, phenolics etc. along with proteolytic enzymes (EC 3.4.21) 26,51 . Apocynaceae (the dogbane family) members comprising of trees, shrubs, woody vines and herbs are distributed primarily in tropical, subtropical and temperate zones. ...
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Plant latex proteases from different species find applications in diverse industries ranging from food to medicine. Family Apocynaceae consists of species producing large quantities of milky latex. Latex is known to be a rich source of proteolytic enzymes or proteases. Proteases, mainly of the cysteine and occasionally serine type, have been characterized from the latices of different species of Apocynaceae. Many of these proteases have also demonstrated stability under a wide range of parameters including temperature, pH and presence of metal ions. The current review is an attempt to elucidate on latex proteases belonging to Apocynaceae family, highlighting those properties that offer potential for their large-scale applications in different industrial sectors.
... In this context, latex has stood out. Estimates show that there are 12 to 35 thousand lactiferous species, and only a few have been evaluated regarding Macroporous latex biomembrane from Hancornia speciosa modulates the inflammatory process and has a debridement effect on wound healing in rats their pharmacological importance 14,15 . Among them, the most explored and known is the rubber tree, from which the latex extracted presents angiogenic and healing properties. ...
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Purpose The angiogenic, osteogenic and anti-inflammatory activity of latex of Hancornia speciosa has been evidenced and indicates pharmacological potential with great applicability in the health area, especially in the wound healing process. The present work aimed to compare the effects of the H. speciosa macroporous latex biomembrane with saline on wound healing. Methods Forty-three Wistar rats were submitted to excisional wound induction procedure and divided into groups according to treatment: saline (G1), and macroporous biomembrane (G2). The animals were euthanized at three, seven, 14, and 21 days after injury induction (DAI), and three animals were used for the debridement test. Morphometric, macroscopic, and microscopic analyses of general pathological processes were performed. Results The macroporous biomembrane minimized necrosis and inflammation during the inflammatory and proliferative phases of the healing process, confirmed by the lower intensity of the crust and the debridement effect. In addition, the wounds treated with the macroporous biomembrane presented greater contraction rates in all the experimental periods analyzed. Conclusions The macroporous biomembrane presents angiogenic, anti-inflammatory and debridement effects, contributing to the healing process, and can be considered a potentially promising new biomaterial to be used as a dressing. Key words Biocompatible Materials; Wound Healing; Anti-Inflammatory Agents; Debridement
... Proteins, enzymes, alkaloids, glycosides, cardenolides, terpenoids, furanocoumarins, and starch are just a few of the bioactive substances that can be found in the latex of different plant species. [11]. Different species of the Euphorbiaceae family's latex have been utilized as an impact modifier and secondary plasticizer for polyvinyl chloride (PVC), as adhesive for glass joints, and in paint formulations [12]. ...
Article
Traditional plastic materials have a negative environmental impact and one potential strategy to reduce this rising plastic pollution is to use compostable materials like bioplastic. An experiment was conducted at RVS School of Engineering and Technology, Dindigul to synthesize bioplastic from agricultural products like corn starch, latex of Euphorbia antiquorum and polyvinyl alcohol (PVA). Two sets of blend bioplastic film samples were prepared using solution casting method; Sample A (corn starch + latex of Euphorbia antiquorum) and Sample B (corn starch + latex of Euphorbia antiquorum + PVA). Studies on the degradation properties were carried out by solubility, swelling and soil burial test. The biodegradability of the samples was investigated by soil burial test. Based on this study, the Sample A film without PVA was found to be highly biodegradable as compared to Sample B. The solubility and swelling tests were performed using organic solvents; ammonia, acetic acid, methanol and water. The swelling property of Sample B film showed less percentage of swelling. The solubility test showed that none of the bioplastic samples were completely soluble in any of the organic solvents. Result of this research work indicated that the bioplastic with incorporation of PVA is a better alternative to conventional plastic films.
... In fact, A. excelsa is a natural host plant for Samia canningi (Hutton), an extant wild species from north-east India, which is reported to be a progenitor of S. ricini (7). There are probably multiple mechanisms that influence the adaptations of S. ricini larvae to herbivory and utilization of diverse host plants (8,9). ...
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Dietary change influenced the life-history traits, nutritional utilization, and midgut serine proteinases in the larvae of the domesticated polyphagous S. ricini , transferred from R. communis (common name: castor; family Euphorbiaceae; the host plant implicated in its domestication) to A. excelsa (common name: Indian tree of heaven; family Simaroubaceae; an ancestral host of wild Samia species). Significantly higher values for fecundity and body weight were observed in larvae feeding on R. communis (Scr diet), and they took less time to reach pupation than insects feeding on A. excelsa (Scai diet). Nevertheless, the nutritional index for efficiency of conversion of digested matter (ECD) was similar for larvae feeding on the two plant species, suggesting the physiological adaptation of S. ricini (especially older instars) to an A. excelsa diet. In vitro protease assays and gelatinolytic zymograms using diagnostic substrates and protease inhibitors revealed significantly elevated levels ( p ≤ 0.05) of digestive trypsins, which may be associated with the metabolic costs influencing slow growth in larvae feeding on A. excelsa . RT-PCR with semidegenerate serine proteinase gene-specific primers, and cloning and sequencing of 3′ cDNA ends identified a large gene family comprising at least two groups of putative chymotrypsins (i.e., Sr I and Sr II) resembling invertebrate brachyurins/collagenases with wide substrate specificities, and five groups of putative trypsins (i.e., Sr III, Sr IV, Sr V, Sr VII, and Sr VIII). Quantitative RT-PCR indicated that transcripts belonging to the Sr I, Sr III, Sr IV, and Sr V groups, especially the Sr IV group (resembling achelase I from Lonomia achelous ), were expressed differentially in the midguts of fourth instars reared on the two plant species. Sequence similarity indicated shared lineages with lepidopteran orthologs associated with expression in the gut, protein digestion, and phytophagy. The results obtained are discussed in the context of larval serine proteinases in dietary adaptations, domestication, and exploration of new host plant species for commercial rearing of S. ricini .
... However, ovicidal activity could be caused by other compounds such as tannins present in superior plants (Seck et al. 2021). Tannins have a toxic effect on some insect pest species and affect the survival and health of individuals in subsequent generations (Konno 2011;Vandenborre et al. 2011). On the other hand, the ovicidal effects of C. procera oil could result from the combined action of different bioactive compounds (Deletre et al. 2015(Deletre et al. , 2016. ...
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Tuta absoluta poses a serious threat to tomato production worldwide as it can cause important yield losses. Its control is currently mainly based on the use of synthetic chemical insecticides, which unfortunately selects resistant populations and entails public health risks. The aim of this study was to evaluate the insecticidal, repellent and sublethal effects of Carapa procera seed oil on all stages of T. absoluta. Larvicidal (by contact and by ingestion), ovicidal and anti-feeding effects were evaluated by testing 1.5%, 3%, 4.5%, 6% and 7.5% concentrations of oil. Larvicidal and ovicidal effects were tested by direct application of Carapa solutions on larvae and eggs but also by feeding the larvae leaves dipped in solutions. The adult repellent effect was investigated by identifying the preferred area on filter paper partly non-treated versus fully treated using LC10, LC50 et LC90 of larvae after ingestion. LC50 was also used on 2-day-old larvae to evaluate the sublethal effects on larval and pupal duration, longevity and adult morphology. Results showed that, regardless of the mode of application, all concentrations had larvicidal effects with a higher dose-response effect and a higher mortality rate via ingestion than via topical application. The ovicidal effect varied with the concentrations tested, the highest mortality rate was obtained at a concentration of 7.5%. At the same dose, Carapa oil reduced large feeding galleries from 92.22 ± 5.02% in controls to 3.33 ± 3.65% at the highest dose and had a repellent effect on 80% of adults. Carapa oil increased larval and pupal duration by 2.14 and 1.35 days, respectively, and reduced adult female longevity by 2.2 days and male longevity by 1.1 days. A deformation rate of 28.33% was observed in newly emerged adults. This study demonstrated insecticidal and insect repellent effects of Carapa oil on different stages of T. absoluta. This botanical oil is a very promising biopesticide to control this major new pest of Solanaceous crops. Its use in an agroecological pest management strategy is discussed.
... To this list may be added E. Tirucalli (Linné) and E. coerulescens, both of which contain potent diterpenoids 12,14,48,49 . The carcinogenic latex contains various serine proteases 50 , terpenoids, lectins, and several esters of diterpene alcohols 14,50,51 . Among some of the tribes of the Namib and Kalahari Euphorbia poison is used in its simplest form, when the white milky latex is sundried to thicken and then directly applied to arrows 21 . ...
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The detection of complex poison recipes applied to ancient hunting weapons has the potential to provide important insights into traditional pharmacological knowledge systems. Yet, recipes comprising many ingredients can be challenging to decipher, especially in older samples that have undergone biodegradation. We present the results of our attempt to analyze samples of poison collected from nineteenth and twentieth century arrowheads from southern Africa, and from a 1000-year-old archaeological bone point. The arrow poison residues and reference samples were analyzed by Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy (ATR FTIR) and Gas Chromatography Mass Spectrometry (GC–MS). The ATR FTIR analysis is primarily able to separate between different arrow poison binder recipes. The extractives identified by GC–MS analysis consist of a multitude of components from both binders and active substances, confirming and adding to the results from the ATR FTIR analyses. We discuss the results in terms of potential biomarkers for arrow poisons in organic residue analyses of archaeological artefacts; that residues of toxic cardiotonic glycosides can be detected on curated and excavated arrow tips of between about 1000 and 100 years old, serves as proof of concept for working with older materials in the future.
... O látex de plantas, uma seiva, normalmente branca, é armazenada no tecido denominado laticífero e exsudada a partir de um ponto de dano nos tecidos da planta, imediatamente após um evento de herbivoria de inseto (KONNO, 2011). Para a planta o látex funciona como reserva de alimento ou de água, produto de excreção de metabólitos residuais, um mecanismo de defesa que repele animais e insetos que fazem herbivoria, matando ou controlando o crescimento de fitopatógenos microbianos e selando áreas feridas (KEKWICK, 2001). ...
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Registrou-se a coleta de látex por Trigona spinipes em cactos, no Jardim Botânico da Univille, do outono à primavera de 2021. Foram anotados os fatores abióticos temperatura, umidade relativa (UR) e luminosidade. Houve variação no horário de coleta em relação às estações. A abundância das abelhas sobre os cactos decresceu de maio a novembro. Euphorbia cooperi foi a planta mais visitada, seguida por E. canariensis e E. grandicornis. No outono, o tempo médio de permanência de abelhas sobre os cactos, para E. canariensis, foi 25:17, em E. cooperi 33:34, em E. grandicornis 10 minutos, e a duração da ida e volta das abelhas para o cacto, para E. cooperi, foi 16:30, para E. canariensis 27 minutos, não havendo dados para E. grandicornis. No inverno, para E. cooperi, o tempo médio foi de 21:48, não havendo dados para E. grandicornis e E. Canariensis, e a duração da ida e volta, para E. cooperi, foi de 14:40, não havendo dados para E. canariensis. Na primavera, a única permanência foi em E cooperi (44 minutos). Para as abelhas, houve variação de atratividade, entre as espécies de cacto, sazonalmente. Verificou-se correlação positiva com horário e temperatura, no outono e inverno, para E. canariensis e E. cooperi.
... Arg. (rubber tree) and Lactuca sativa L. (Konno, 2011). Exudates are also obtained from various fruits, for example, the Carica papaya L. latex comprising of four cysteine proteases. ...
Article
Many investigations have been carried out analyzing the characteristics of various materials for development of edible coatings/films for food applications. Subsequent modifications for improvement and ameliorating the film/coating characteristics has been the pivot of research in the last decade. An inclination has developed among researchers towards use of plant-based active substances for development of food products and food packaging. Plant based materials have been widely used as antioxidants or antimicrobials in film/coating formulations. Such materials include plant extracts, essential oils, oleoresins, and plant exudates. The compounds present in these materials mostly perform the antibacterial, antiviral, antifungal, antioxidant, and anti-browning functions. Such compounds may also be isolated from plant materials and then incorporated into edible coatings/films. This document is a comprehensive review describing the plant derived active substances used as antimicrobial and antioxidant components in edible films/coating. It also focuses on their applications for improving quality of different foods along with their safety regulations.
... NR consists mainly of cis-1,4-polyisoprene having an average molecular weight of ~1 × 10 6 Da and is the end product of a biosynthetic pathway which does not go through catabolism. Guayule produces NR in response to environmental stresses (Allen et al., 1987;Benedict et al., 2008;Bonner, 1943;Bucks et al., 1985;Cornish and Backhaus, 2003;Dong et al., 2021;Downes and Tonnet, 1985;Hunsaker et al., 2019;Miyamoto and Bucks, 1985;Nelson et al., 2019;Ponciano et al., 2012;Veatch-Blohm et al., 2007) and together with resin, NR seals wounded sites upon pathogen attack to prevent infection (El Moussaoui et al., 2001;Konno, 2011). ...
... The T. guianensis naturally secretes a large amount of exudate and has secretory ducts distributed in the secondary phloem and in the radial ducts of the secondary xylem (Lacchia and Guerreiro 2009). However, the main source of exudates on which marmosets feed are the numerous traumatic ducts produced by scarification, which is one of the tree's main defense mechanisms (Konno 2011). Observed tree responses to wounds include increased tylosis and sclerification, formation of periderm and scar tissue in the bark and xylem (War et al. 2012). ...
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The black-tufted-ear marmoset (Callithrix penicillata É. Geoffroy) has a specialized dentition that allows it to gouge holes in tree barks to obtain exudates as food. Tapirira guianensis Aubl. is the most exploited tree species most used by black-tufted-ear marmosets. Wounds to a tree can stimulate morphological responses in the tree bark that are associated with the recovery of plant tissues. The present study, characterizes the morphology of gouged and non-gouged bark sections of T. guianensis trees in three urban forests of the Brazilian Cerrado. The anatomy and histochemistry of non-gouged bark and tissues near the holes were characterized. In addition to the constitutive secretory ducts, other ducts of traumatic origin are formed in the bark or their secretion is enhanced after excavation by the marmoset gouging. The traumatic ducts are larger, more numerous, and concentrated in the phloem near the cambial region, where exudates on which the marmosets feed are secreted. Other defensive responses in wounded trees included increased formation and sclerification of tyloses, reconstitution of the periderms in the bark, vessel obstruction by gum in the xylem, formation of scar tissue, and vessel obstruction by an exudate in the xylem. The tree appears to be able to recover from the wounds caused by marmosets, and the gouging caused by marmosets may stimulate the defense mechanisms of the tree.
... For instance, maize leaves produce terpenoid and indole compounds in response to infection by caterpillars for attracting wasps that feed on caterpillars [31]. Plants can also protect themselves from insect attacks via production of sticky metabolites such as latex or resins that trap insects [49]. ...
Article
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In their environment, plants interact with a multitude of living organisms and have to cope with a large variety of aggressions of biotic or abiotic origin. What has been known for several decades is that the extraordinary variety of chemical compounds the plants are capable of synthesizing may be estimated in the range of hundreds of thousands, but only a fraction has been fully characterized to be implicated in defense responses. Despite the vast importance of these metabolites for plants and also for human health, our knowledge about their biosynthetic pathways and functions is still fragmentary. Recent progress has been made particularly for the phenylpropanoids and oxylipids metabolism, which is more emphasized in this review. With an increasing interest in monitoring plant metabolic reprogramming, the development of advanced analysis methods should now follow. This review capitalizes on the advanced technologies used in metabolome mapping in planta, including different metabolomics approaches, imaging, ux analysis, and interpretation using bioinformatics tools. Advantages and limitations with regards to the application of each technique towards monitoring which metabolite class or type are highlighted, with special emphasis on the necessary future developments to better mirror such intricate metabolic interactions in planta.
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Six compounds were isolated from lettuce latex. They were identified as 2,5‐dihydroxybenzaldehyde (1), 3β‐hydroxy‐4,15‐dehydrograndolide (2), annuolide D (3), lactucin (4), lactucopicrin (5), and hanphyllin (6). Bioassays showed that the inhibition rate of compound 1 (2,5‐dihydroxybenzaldehyde) and 6 (hanphyllin, a sesquiterpene lactone) on the weight gain of S. litura were 52.4% and 10%, respectively, at the concentration of 100 μg/g. RNA‐seq analyses showed that larval exposure to compound 1 down‐regulated the genes associated with heterobiotic metabolism including drug metabolism‐cytochrome P450, metabolism of xenobiotics by cytochrome P450, retinol metabolism, glutathione metabolism, and drug metabolism‐other enzymes (mainly uridine diphosphate glucuronyltransferase, UGTs). RT‐qPCR further confirmed that 33 genes in the family of carboxylesterase (CarE), P450s and UGTs were down‐regulated by compound 1. The activities of CarE, P450s and UGTs in the larvae fed on diets containing compound 1 were significantly lower than those fed on control diets, with the inhibition for the three detoxification enzymes being 55.4%, 53.9%, and 52.9%. These findings suggest that secondary metabolites including 2,5‐dihydroxybenzaldehyde in the latex play a key role in protecting lettuce from insect herbivory.
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The latex of Ipomoea (Convolvulaceae) is a source of a special kind of acylsugars called resin glycosides, which are highly appreciated because of their biological activities (i.e. laxative, antimicrobial, cytotoxic etc.). Most research has been conducted in perennials with tuberous roots, where resin glycosides are stored. However, their content and variation are unknown in annual vines that lack this type of root, such as in the case of Ipomoea parasitica. This species contains research/biological and human value through its fast growth, survival in harsh environments, and employment in humans for mental/cognitive improvements. These qualities make I. parasitica an ideal system to profile resin glycosides and their variations in response to edaphoclimate. Topsoil samples (0–30 cm depth) and latex from petioles of I. parasitica were collected in two localities of central Mexico. The latex was analyzed through UHPLC-ESI-QTOF, and soil physico-chemical characteristics, the rainfall, minimum, average, and maximum temperatures were recorded. We also measured canopy (%), rockiness (%), and plant cover (%). A Principal Component Analysis was conducted to find associations between edaphoclimate and the resin glycosides. Forty-four resin glycosides were found in the latex of I. parasitica. Ten correlated significantly with three components (47.07%) and contained tetrasaccharide, pentasaccharide, and dimers of tetrasaccharide units. Five resin glycosides were considered constitutive because they were in all the plants. However, exclusive molecules to each locality were also present, which we hypothesize is in response to significant microhabitat conditions found in this study (temperature, clay content, pH, and potassium). Our results showed the presence of resin glycosides in I. parasitica latex and are the basis for experimentally testing the effect of the conditions above on these molecules. However, ecological, molecular, and biochemical factors should be considered in experiments designed to produce these complex molecules.
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We discovered an egg batch of a moth species laid on the leaves of Ficus microcarpa(L.f)(Rosales: Moraceae)at Kyushu University. The larvae hatched from the eggs were fed on both F. microcarpa and Morus alba(L.)(Rosales: Moraceae). Mulberry latex is known to be toxic to most lepidopteran larvae, with the exception of a few, such as Bombyx mori(Linnaeus)(Lepidoptera: Bombycidae). However, to our surprise, the larvae developed normally, pupated, and emerged as fertile moths. We also investigated whether the larvae of the species fed on M. alba leaves and developed normally throughout the larval stage. Finally, we identified the species as Spodoptera litura(Fabricius)(Lepidoptera: Noctuidae)through observation of the external morphology of the moths and sequencing of the cytochrome oxidase I(COI)gene.
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Millions of people, particularly in developing nations, depend on collecting exudates from the wild as a means of their livelihood. However, the use and production of exudates have declined in the last 100 years mainly due to the availability of superior and cheaper synthetic alternatives as well as the unsustainable tapping technique that leads to the death of the tapped plant individuals. In this contribution, we present the status of exudates-producing plant species in Southeast Asia, including the diversity, distribution, use, conservation status, protection, and ex situ conservation. The results of the present study can be used as a baseline for evolving a conservation strategy and action plant for exudates-producing plant species in Southeast Asia. Furthermore, the results can also be used to support the sustainable utilization of exudates-producing plant species in the region.
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Plant latex is a sticky emulsion exuded from laticifer once the plant is damaged. Latex is an essential component of plant defense against herbivores. Lettuce ( Lactuca sativa L.) in the compositae family has relatively fewer insect herbivores compared with other leaf vegetables. Our bioassay showed that the larvae of a generalist lepidopteran pest Spodoptera litura (Fabricius) avoided feeding on living lettuce plants. However, the larvae rapidly damaged the excised leaves unable to produce latex. The methanol extract of lettuce latex exhibited antifeedant activity. Six compounds were isolated from lettuce latex. They were identified as 2,5-dihydroxybenzaldehyde ( 1 ), 3 β -hydroxy-4,15-dehydrograndolide ( 2 ), annuolide D ( 3 ), lactucin ( 4 ), lactucopicrin ( 5 ), and hanphyllin ( 6 ). Bioassays showed that compounds 1 (2,5-dihydroxybenzaldehyde) and 6 (hanphyllin, a sesquiterpene lactone) inhibited larval growth of S. litura at the concentration of 100 µ g/g. RNA-seq analyses showed that larval exposure to compound 1 down-regulated the genes associated with heterobiotic metabolism including drug metabolism-cytochrome P450, metabolism of xenobiotics by cytochrome P450, retinol metabolism, glutathione metabolism, drug metabolism-other enzymes (mainly uridine diphosphate glucuronyltransferase, UGTs). RT-qPCR further confirmed that 33 genes in the family of carboxylesterase (CarE), P450s and UGTs were down-regulated by compound 1 . The activities of CarE, P450s and UGTs in the larvae fed on diets containing compound 1 were significantly lower than those fed on control diets. These findings suggest that secondary metabolites including 2,5-dihydroxybenzaldehyde in the latex plays a key role in protection of lettuce from insect herbivory.
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Floral bracts (bracteoles, cataphylls) are leaf-like organs that subtend flowers or inflorescences but are of non-floral origin; they occur in a wide diversity of species, representing multiple independent origins, and exhibit great variation in form and function. Although much attention has been paid to bracts over the past 150 years, our understanding of their adaptive significance remains remarkably incomplete. This is because most studies of bract function and evolution focus on only one or a few selective factors. It is widely recognised that bracts experience selection mediated by pollinators, particularly for enhancing pollinator attraction through strong visual, olfactory, or echo-acoustic contrast with the background and through signalling the presence of pollinator rewards, either honestly (providing rewards for pollinators), or deceptively (attraction without reward or even trapping pollinators). However, studies in recent decades have demonstrated that bract evolution is also affected by agents other than pollinators. Bracts can protect flowers, fruits, or seeds from herbivores by displaying warning signals, camouflaging conspicuous reproductive organs, or by providing physical barriers or toxic chemicals. Reviews of published studies show that bracts can also promote seed dispersal and ameliorate the effects of abiotic stressors, such as low temperature, strong ultraviolet radiation, heavy rain, drought, and/or mechanical abrasion, on reproductive organs or for the plants' pollinators. In addition, green bracts and greening of colourful bracts after pollination promote photosynthetic activity, providing substantial carbon (photosynthates) for fruit or seed development, especially late in a plant's life cycle or season, when leaves have started to senesce. A further layer of complexity derives from the fact that the agents of selection driving the evolution of bracts vary between species and even between different developmental stages within a species, and selection by one agent can be reinforced or opposed by other agents. In summary, our survey of the literature reveals that bracts are multifunctional and subject to multiple agents of selection. To understand fully the functional and evolutionary significance of bracts, it is necessary to consider multiple selection agents throughout the life of the plant, using integrative approaches to data collection and analysis.
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Silkworm, Bombyx mori , and its faeces are notable healthy foods because of their biologically active components originating from mulberry ( Morus spp.) leaves. However, in modern sericulture, silkworms are reared on artificial diet made primarily from defatted soybeans and dried mulberry leaf powder throughout the year. Neither the contents of functional components nor the biological activities of silkworms and their faeces raised on artificial diet have been investigated. Therefore, 1-deoxynojirimycin (DNJ) content, α-glucosidase inhibitory activity, Trolox equivalent antioxidant capacity (TEAC), total phenolic, total flavonoid and chlorophyll content were evaluated in silkworms and their faeces reared on mulberry leaves, artificial diet and then artificial diet switched to mulberry leaf from the fifth instar for four days. The DNJ content of silkworms depended on that in their diet and was significantly lower in silkworms fed with artificial diet than in those fed with mulberry leaves similar to the α-glucosidase inhibitory activity. On the contrary, TEAC, total phenolic content and total flavonoid content were similar in all silkworms regardless of feeding conditions. In the faeces of the artificial diet-reared group, TEAC, total phenolic content and total flavonoid content were significantly higher than those of the mulberry leaf-reared group. Chlorophyll content in faeces depended on the content of diet, whereas that in silkworms was low regardless of the diet type. The biological activities and contents of functional compounds in the artificial diet-reared group were at similar levels with those of the mulberry leaf-reared group when the diet switched to mulberry leaf from the first day of the fifth instar for four days, indicating that the biological activities and content of functional components in silkworms and its faeces are defined by diet and changeable over a short period.
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The effect of high hydrostatic pressure (HHP) and the proteolytic fraction P1G10 from papaya latex was studied to find out whether a synergy exists in the growth inhibition of Botrytis cinerea in grape juice, contributing to the improvement of conservation techniques and extending the shelf life and quality of food products. Grape juice (GJ) diluted to 16 °Brix with a water activity (aw) of 0.980 was prepared from a concentrated GJ and used in this study. Results indicated a 92% growth inhibition of B. cinerea when exposed to 1 mg/mL of P1G10 and 250 MPa/4 min of pressure treatment. The proximate composition and antioxidant compounds present in the GJ were not significantly affected after the treatments. Eight phenolic compounds and two flavonoids in GJ were identified and quantified, with values fluctuating between 12.77 ± 0.51 and 240.40 ± 20.9 mg/L in the control sample (0.1 MPa). The phenolic compounds showed a significant decrease after the applied treatments, with the HHP sample having a content of 65.4 ± 6.9 mg GAE/100 mL GJ. In conclusion, a synergistic effect at moderate HHP of 250 MPa/4 min with the addition of P1G10 was observed, and the successful development of a stable and acceptable GJ product was possible.
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Synthetic polymers are chemicals of emerging concern for the environment, which is mainly attributed to their persistence in environmental compartments. On the other hand, polymers exist in nature as well. They are regarded of no concern for the environment. The present article focusses on the environmental fate of natural polymers and the implications on the persistence assessment for synthetic polymers. Natural polymers vary widely in structure, function, and properties. Crystallinity, wettability and surface area are important influencing factors on the (bio)degradation kinetics. Chemical and enzymatic hydrolysis is the most important process for the degradation of natural polymers, which for particulate material takes place either by bulk or surface erosion. Some natural polymers are degraded rapidly, but in other cases, degradation of natural polymers takes very long until complete mineralization. These differences in biodegradability are a result of evolution as they have to fulfil specific functions in nature which might require a certain persistency. Consequently, many natural polymers would have to be considered persistent or very persistent (P or vP) based on the available studies using the standard assessment approach. At the same time, they are considered no concern to the environment for good reasons. The analysis emphasizes that mineralization alone is not a resilient persistence endpoint for polymers. This needs to be recognized when assessing synthetic polymers, many of which would fulfil the existing P/vP criteria as well. For such synthetic polymers, it would be important to establish meaningful endpoints and polymer specific criteria to enable an adequate persistence assessment using a weight-of-evidence approach.
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As proteins execute vital physiological and biochemical functions in organisms, proteomics has become a powerful high-throughput tool in revealing metabolism alterations and understanding the mechanisms involved in diverse status of plants. Mulberry is a traditional tree species with great economic value in foraging silkworms, food ingredients, pharmaceutical chemicals, and ecological applications. Since the sequencing of the mulberry genomes was completed, increasing efforts associated with proteomics analysis have been carried out to understand the physiology of mulberry trees. This review summarizes mulberry proteomic studies performed in recent years. We particularly focused on the responses of proteomics to biotic and abiotic stress and the interactions between mulberry and silkworm, aiming to provide insights for future molecular biology research and enumerate the prospects for diversified breeding of mulberry trees in industry.KeywordsProteomicsBiotic stressAbiotic stressMulberry
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Tuta absoluta poses a serious threat to tomato production worldwide as it can cause more than 80% yield losses. Its control is currently mainly based on the use of synthetic chemical insecticides, which unfortunately selects resistant populations and entails public health risks. The aim of this study was to evaluate the insecticidal, repellent and sublethal effects of Carapa procera seed oil on all stages of T. absoluta . Larvicidal (by contact and by ingestion), ovicidal and anti-feeding effects were evaluated by testing 1.5%, 3%, 4.5%, 6% and 7.5% concentrations of oil. Larvicidal and ovicidal effects were tested by direct application of Carapa solutions on larvae and eggs but also by feeding the larvae leaves dipped in solutions. The adult repellent effect was investigated by identifying the preferred area on filter paper partly non-treated vs fully treated using LC 10 , LC 50 et LC 90 of larvae after ingestion. LC 50 was also used on 2-day-old larvae to evaluate the sublethal effects on larval and pupal duration, longevity and adult morphology. Results showed that, regardless of the mode of application, all concentrations had larvicidal effects with a higher dose-response effect and a higher mortality rate via ingestion than via topical application. The ovicidal effect varied with the concentrations tested, the highest mortality rate was obtained at a concentration of 7.5%. At the same dose, Carapa oil reduced large feeding galleries from 92.22 ± 5.02% in controls to 3.33 ± 3.65% at the highest dose and had a repellent effect on 80% of adults. Carapa oil increased larval and pupal duration by 2.14 and 1.35 days, respectively, and reduced adult female longevity by 2.2 days and male longevity by 1.1 days. A deformation rate of 28.33% was observed in newly emerged adults. This study demonstrated insecticidal and insect repellent effects of Carapa oil on different stages of T. absoluta . This botanical oil is a very promising biopesticide to control this major new pest of Solanaceous crops. Its use in an agroecological pest management strategy is discussed.
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Wounding leaves or stems of Lactucaspecies releases a milky latex onto the plant surface. We have examined the constituents of latex from Lactuca sativa (lettuce) cv. Diana. The major components were shown to be novel 15-oxalyl and 8-sulfate conjugates of the guaianolide sesquiterpene lactones, lactucin, deoxylactucin, and lactucopicrin. The oxalates were unstable, reverting to the parent sesquiterpene lactone on hydrolysis. Oxalyl derivatives have been reported rarely from natural sources. The sulfates were stable and are the first reported sesquiterpene sulfates from plants. Unusual tannins based on 4-hydroxyphenylacetyl conjugates of glucose were also identified. Significant qualitative and quantitative variation was found in sesquiterpene lactone profiles in different lettuce varieties and in other Lactuca spp. The proportions of each conjugate in latex also changed depending on the stage of plant development. A similar profile was found in chicory, in which oxalyl conjugates were identified, but the 8-sulfate conjugates were notably absent. The presence of the constitutive sesquiterpene lactones was not correlated with resistance to pathogens but may have a significant bearing on the molecular basis of the bitter taste of lettuce and related species. The induced sesquiterpene lactone phytoalexin, lettucenin A, was found in the Lactuca spp. but not in chicory.
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Using in situ RNA hybridization and immunohistochemical techniques, we investigated the tissue-specific and light-dependent expression of four genes involved in phenylpropanoid metabolism in various parts o f parsley ( Petroselinum crispum) seedlings.The genes encode phenylalanine amm onia-lyase (PAL) and 4-coum arate: Co A ligase (4 CL), two enzymes of general phenylpropanoid metabolism; chalcone synthase (CHS), the keyenzyme of flavonoid biosynthesis; and bergaptol O-methyltransferase (BMT), a late enzyme of the furanocoumarin pathway. In young leaves, PAL and 4 CL genes were expressed predominantly and in a coordinated fashion in epidermal cells, young xylem cells of vascularbundles, and epithelial cells of oil ducts. The gene(s) encoding BMT wasactive exclusively in the epithelial cells of oil ducts, where as CHS gene expression was largely confined to the epidermis. In shoot and root apices, PAL, 4 CL and CHS m R N A s were detectable at low levels without distinct patterns. The corresponding proteins, however, accumulated preferentially in the protoderm and pith meristem of the shoot apex and in root-cap cells. A gene encoding pathogenesis-related protein 1 (PR 1)was analyzed in rootsfor comparison and was found to be expressed predominantly in the cortical cells o f root tips. The expression o f all genes investigated was, to a greater or lesser extent, dependent on light conditions and tissue age, with highest levels occurring in newly differentiated, light-exposed tissue. In the leaf epidermis o f seedlings illuminated for 20 h, PAL and CHS m R N A s and proteins, as well as 4 CL protein, were particularly abundant. © 2009 Walter de Gruyter.
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A revised and updated classification for the families of flowering plants is provided. Many recent studies have yielded increasingly detailed evidence for the positions of formerly unplaced families, resulting in a number of newly adopted orders, including Amborellales, Berberidopsidales, Bruniales, Buxales, Chloranthales, Escalloniales, Huerteales, Nymphaeales, Paracryphiales, Petrosaviales, Picramniales, Trochodendrales, Vitales and Zygophyllales. A number of previously unplaced genera and families are included here in orders, greatly reducing the number of unplaced taxa; these include Hydatellaceae (Nymphaeales), Haptanthaceae (Buxales), Peridiscaceae (Saxifragales), Huaceae (Oxalidales), Centroplacaceae and Rafflesiaceae (both Malpighiales), Aphloiaceae, Geissolomataceae and Strasburgeriaceae (all Crossosomatales), Picramniaceae (Picramniales), Dipentodontaceae and Gerrardinaceae (both Huerteales), Cytinaceae (Malvales), Balanophoraceae (Santalales), Mitrastemonaceae (Ericales) and Boraginaceae (now at least known to be a member of lamiid clade). Newly segregated families for genera previously understood to be in other APG-recognized families include Petermanniaceae (Liliales), Calophyllaceae (Malpighiales), Capparaceae and Cleomaceae (both Brassicales), Schoepfiaceae (Santalales), Anacampserotaceae, Limeaceae, Lophiocarpaceae, Montiaceae and Talinaceae (all Caryophyllales) and Linderniaceae and Thomandersiaceae (both Lamiales). Use of bracketed families is abandoned because of its unpopularity, and in most cases the broader circumscriptions are retained; these include Amaryllidaceae, Asparagaceace and Xanthorrheaceae (all Asparagales), Passifloraceae (Malpighiales), Primulaceae (Ericales) and several other smaller families. Separate papers in this same volume deal with a new linear order for APG, subfamilial names that can be used for more accurate communication in Amaryllidaceae s.l., Asparagaceace s.l. and Xanthorrheaceae s.l. (all Asparagales) and a formal supraordinal classification for the flowering plants.
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The Monarch butterfly (Danaus plexippus) sequesters cardiac glycosides (CG) for its chemical defense against predators. Larvae and adults of this butterfly are insensitive towards dietary cardiac glycosides, whereas other Lepidoptera are sensitive and intoxicated by ouabain. Ouabain inhibits Na(+),K(+)-ATPase by binding to its α-subunit. We have amplified and cloned the DNA-sequence encoding the respective ouabain binding site. Instead of the amino acid asparagine at position 122 in ouabain-sensitive insects, the Monarch has a histidine in the putative ouabain binding site, which consists of 12 amino acids. Starting with the CG-sensitive Na(+),K(+)-ATPase gene fromDrosophila, we converted pos. 122 to a histidine residue as inDanaus plexippus by site-directed mutagenesis. Human embryonic kidney cells (HEK) (which are sensitive to ouabain) were transfected with the mutated Na(+),K(+)-ATPase gene in a pSVDF-expression vector and showed a transient expression of the mutatedDrosophila Na(+),K(+)-ATPase. When treated with ouabain, the transfected cells tolerated ouabain at a concentration of 50 mM, whereas untransformed controls or controls transfected with the unmutatedDrosophila gene, showed a substantial mortality. This result implies that the asparagine to histidine exchange contributes to ouabain insensitivity in the Monarch. In two other CG-sequestering insects, e.g.,Danaus gilippus andSyntomeida epilais, the pattern of amino acid substitution differed, indicating that the Monarch has acquired this mutation independently during evolution.
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Ehrlich and Raven's postulate that rapid diversification follows innovation in plant defense has often been invoked a posteriori for plant lineages of unusual diversity and chemical distinctiveness. The postulate can be more rigorously tested by defining a novel class of defense using chemical and/or anatomical criteria, independent of taxonomic lineage. If multiple plant lineages have evolved the new defense type, then according to the postulate they should be consistently more diverse than their sister groups (of equal age, by definition) when the latter retain the primitive defensive repertoire. Secretory canals are an independently defined, repeatedly evolved feature that functions to protect plants from herbivores and pathogens. The canals might therefore be expected to allow plant radiation in an adaptive zone of reduced herbivory and disease. We have quantified the evidence for this hypothesis by comparing the diversities of lineages that have independently evolved canal systems with their sister groups for as many plant lineages as current taxonomic evidence allows. A sign test showed that canal-bearing lineages have consistently higher diversities than their sister groups (P = .0021). Explanations for this result, other than selective advantage conferred by secretory canals, are examined and provisionally rejected.
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The leaves of the privet tree, Ligustrum obtusifolium (Oleaceae), retain a strong lysine-decreasing activity caused by enzymatically-activated oleuropein, an iridoid glycoside. Protein treated with this activity become innutritive to insects because of the loss of lysine. We previously found that several privet specialist caterpillars secrete high concentrations of glycine in their digestive juices. Previous in vitro experiments showed that glycine inhibits lysine-decreasing activity of oleuropein. Therefore, we hypothesized that the lysine-decreasing activity acts to defend privet tree against herbivores and that glycine secretion by insects is an adaptive trait to counter the privet defense. In the present study, we aimed to examine whether these assumptions hold true under physiological conditions, and performed in vivo bioassays and physiological analyses using the Eri silkworm, Samia ricini (Saturniidae), a non-privet specialist. Significant decreases in larval growth and lysine concentration in the midgut lumen were observed when larvae were fed intact privet leaves compared to when they were fed heat inactivated privet leaves. These decreases were inhibited when larvae were fed intact privet leaves together with glycine, indicating that the privet defense with oleuropein and the specialist adaptation with glycine do function under physiological conditions. This study thus provides a rare view into the detailed physiological impacts of anti-nutritive plant defense and insect physiological adaptation in vivo.
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This study describes the digestive protease activity extracted from the gut of fifth-instar Monarch butterfly larvae, and its proteolytic activity on latex proteins of their host plant, Calotropis procera (the milkweed) and related non-host species from the milkweed family. Gut extracts digested azocasein, BANA and BApNA. Cysteine protease inhibitors such as E-64 and iodoacetamide inhibited proteolytic activity on azocasein; however, the serine protease inhibitors PMSF and leupeptin were more effective. Gut extracts promptly digested LP and were not affected by endogenous latex proteases. Gut extracts, however, did not digest LP from Cryptostegia grandiflora and only slightly digested LP from Plumeria rubra, two plant species that are not consumed by Monarch larvae. The protein profiles of latex proteins extracted from healthy and attacked plants were different. A protein identified as glycoside hydrolase was detected in increased concentrations in latex from damaged plants. Larvae fed on artificial diets containing 1% or 5% latex proteins were not adversely affected and gained weight faster than control larvae. These results provide new information on the resistance of Monarch larvae fed on C. procera and suggest that the ability of Monarch proteolytic enzymes to promptly digest LP can explain (at least in part) how these insects overcome the defensive proteins found in C. procera latex.
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Latex is actively secreted on wounded unripe fruits from Caricapapaya. We describe the changes in peptide composition by SDS-PAGE analysis of latex from C.papaya collected at various times after incision of the unripe fruit. Non random changes in the relative amount of several peptides occur during latex coagulation. The measurement of amidase activity of coagulating latex shows three peaks of activity between 2 and 1200 s. The major activity is found at 1000 s, which is when coagulation is under way. The data from in situ proteolytic activity experiments confirm the presence of active enzyme(s) when latex begins to flow from damaged fruits.
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Many plants contain carbohydrate-binding proteins that are commonly designated as lectins, agglutinins, or hemagglutinins. Due to the obvious differences in molecular structure, biochemical properties, and carbohydrate-binding specificity, plant lectins are usually considered a complex and heterogeneous group of proteins. Recent advances in the structural analysis of lectins and molecular cloning of lectin genes enable subdividision of plant lectins in a limited number of subgroups of structurally and evolutionary related proteins. Four major lectin families, namely, the legume lectins, the chitin-binding lectins composed of hevein domains, the type 2 ribosome-inactivating proteins, and the monocot mannose-binding lectins comprise the majority of all currently known plant lectins. In addition to these four large families the jacalin-related lectins, the amaranthin family, and the Cucurbitaceae phloem lectins are now recognized as separate subgroups. Each of the above-mentioned lectin families is discussed in detail. The description of the individual lectin families includes (1) a brief historical note, (2) an overview of the occurrence, molecular structure, and primary structure of the lectins, (3) a detailed discussion of the structure of the gene(s) and the biosynthesis and posttranslational processing of the primary translation products, (4) a summary of carbohydrate-binding specificity, (5) if relevant a note on the occurrence of lectin-related proteins, (6) a description of the three-dimensional structure of the lectins and the protomers, (7) a detailed discussion of the molecular evolution, and (8) a critical assessment of the physiological role of each group of lectins. Lectins that cannot be classified into one of the seven groups are discussed separately. General conclusions about the structure, evolution, and function of plant lectins are summarized in the concluding remarks.
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Methanol extracts of vine latex of four cultivars of sweetpotato [Ipomoea batatas (L.) Lam.] were analyzed for their chemical phenolic composition by reversed-phase HPLC. Major components were identified as hexadecyl, octadecyl, and eicosyl p-coumarates by an evaluation of data from UV spectra, hydrolysis, synthesis, and GC/MS of their trimethylsilyl derivatives. Both Z- and E-isomers of the phenolic acid were found, with the latter predominating. Trace quantities of hexadecyl (Z)- and (E)-ferulates were also identified in ester concentrates. Levels of octadecyl (E)-p-coumarate ranged from 0.7% fresh weight in cv. Resisto to almost 2% in cv. Jewel, while the hexadecyl ester levels were only 1/4 to 1/3 these values. Levels of the Z-esters were 1/10 to 1/20 of the levels of the corresponding E-isomers. Levels of the esters in cv. Jewel sweetpotato root latex were 2-10-fold the levels in the vine latex, while the ratio of E-esters to Z-esters was found to be 7-14-fold. The concentration of Z-esters among the sweetpotato cultivars tested correlated closely with the leaf feeding index for the sweetpotato weevil (Cylas formicarius) (R(2): C-20 = 0.96; C-18 = 0.98; C-16 = 0.71). The results indicate a possible relationship between latex chemistry and insect resistance that might be exploited via plant breeding.
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Latex is a sticky emulsion that exudes upon damage from specialized canals in about 10% of flowering plant species. Latex has no known primary metabolic function and has been strongly implicated in defense against herbivorous in-sects. Here we review historical hypotheses about the function of latex, evi-dence that it serves as a potent defense, and the chemistry and mode of action of the major constituent defense chemicals and proteins across a diversity of plant species. We further attempt to synthesize the characteristics of latex as a coordinated plant defense system. Herbivores that feed on latex-bearing plants typically evade contact with latex by severing the laticifers or feeding intercellularly, or may possess physiological adaptations. Convergent evolu-tion appears to be rampant both in plants with latex and insects that exploit latex-bearing plants. Because latex shows phenotypic plasticity, heritability, and macoevolutionary lability, it is an ideal system to study plant-herbivore interactions using evolutionary approaches.
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Midgut and body tissues of caterpillars of the black swallowtail butterfly (Papilio polyxenes Fabr.) possess high enzymatic activity that catalyzes the detoxification of linear furanocoumarins, thus explaining the tolerance of P. polyxenes to these phototoxins. Observations from nature indicate that P. polyxenes caterpillars are less tolerant toward the presence of angular furanocoumarins in potential host plants, and our studies with a commonly occurring angular furanocoumarin suggest that metabolic detoxification of such compounds by P. polyxenes occurs at a relatively slower rate than with the linear analogs. The capacity to detoxify dietary furanocoumarins is a major determinant of host plant acceptability by P. polyxenes; furthermore, this phenomenon represents a clear example of herbivore circumvention of a normally effective host-plant-resistance mechanism.
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Plants deploy an arsenal of chemical defences against invading herbivores (e.g. Rosenthal and Berenbaum, 1991). Although hundreds of natural products have been characterized, the mode of actions is known for only a few. Our focus is on ‘antinutrients’, a term that has been used in the entomological literature without sufficient definition. Anti-nutrients diminish nutrient bioavailability by chemically modifying the nutrient, forming less active complexes with the nutrient, or by hindering digestion, absorption or utilization of the nutrient. Defining criteria for an antinutrient are (1) the symptoms produced by the antinutrient resemble those caused by insufficiency of a given nutrient and (2) nutrient treatment alleviates the effect of the antinutrient.
Article
;Two rubber particle protein genes and one latex gene in fig tree (Ficus carica) have been isolated and their expression following various abiotic stress treatments have been investigated. The two major proteins that are tightly associated with the catalytically active rubber particles have been sequenced to be peroxidase (POX) and trypsin inhibitor (TRI). A cDNA encoding a basic class I chitinase (CHI) has also been isolated from the fig tree latex. Wounding treatment strongly induced the expression of the three stress-related genes. Among the abiotic stresses investigated, drought treatment greatly induced the expression of POX, whereas the expression of CHI and TRI decreased after the same treatment. Cold treatment reduced slightly the transcript levels of the thee genes, and NaCl reduced marginally the expression of CHI. The expression of POX, CHI, and TRI was induced by jasmonic acid and abscisic acid, by jasmonic acid, and by salicylic acid, respectively. Different expression of the stress-related genes following various abiotic stress or plant hormone treatments suggests that a crosstalk exists between the signal transduction pathways elicited by abiotic stresses and hormones in plants. Our present results showing the expression of stress-related proteins on the surface of rubber particles and latex in F. carica also imply the possible role of rubber particles and latex in defense in rubber-producing plant species.
Article
Plants respond to insect feeding with a number of defense mechanisms. Using maize genotypes derived from Antiquan germ plasm that are resistant to Lepidoptera, we have demonstrated that a unique 33-kD cysteine proteinase accumulates in the whorl in response to larval feeding. The abundance of the proteinase increased dramatically at the site of larval feeding after 1 hr of infestation and continued to accumulate for as long as 7 days. The 33-kD cysteine proteinase was most abundant in the yellow-green portion of the whorl—the normal site of larval feeding and the tissue that has the greatest inhibitory effect on larval growth in bioassays. The proteinase was expressed in response to wounding and was found in senescent leaves. It may be a marker of programmed cell death. The gene coding for the proteinase, mir1, has been transformed into Black Mexican Sweet callus. When larvae were reared on callus expressing the proteinase, their growth was inhibited ∼60 to 80%. The expression of a cysteine proteinase, instead of a cysteine proteinase inhibitor, may be a novel insect defense mechanism in plants.
Article
To determine if the arrangement of secretory canals in leaves affects foraging by folivorous insects, we examined the behaviors of 33 species found on diverse canal-bearing plants. Insect behaviors were categorized into three principal classes: vein cutting, trenching, and neither behavior. Canal architectures were ascertained by damaging leaves with standardized tests and measuring the secretory response Our observations document a precise correspondence between herbivore behavior and canal morphology. Vein-cutting insects occur on plants with arborescent canals (resin canals in Anacardiaceae and nonarticulated laticifers in Apocynaceae, Asclepiadaceae, and Moraceae). By severing the secretory canals in leaf veins, insects prevent the flow of secretion to distal branches of the canals. Trenching insects, in contrast, are found on plants with net-like canal systems (anastomosing articulated laticifers in Asteraceae and Caricaceae, and exuding phloem in Cucurbitaceae). To eliminate secretion outflow from these plants, the insects must transect all strands of the network by cutting a trench. The secretory canals of the Convolvulaceae (nonanastomosing articulated laticifers) differ from the preceding categories in being restricted primarily to the major leaf veins. The behavior of herbivores on this family is also distinct: all feed between the major veins without prior vein cutting or trenching. Thus, insects employ the same behavior on similar canal architectures, even when their host plants otherwise differ in taxonomy, secondary chemistry, and canal type. The occurrence of vein-cutting and trenching behaviors in multiple lineages of insects that include caterpillars, beetles, and katydids indicates that the behaviors have evolved repeatedly, apparently through convergence. Our comparative analysis supports the view that these preingestive behaviors function specifically to deactivate defensive canal systems.
Article
:Using in situ RNA/RNA hybridization, enzyme immunolocalization, and histochemical techniques, several phenylpropanoid biosynthetic activities and products were localized in tissue sections from various aerial parts of parsley (Petroselinum crispum) plants at different developmental stages. The enzymes and corresponding mRNAs analyzed included two representatives of general phenylpropanoid metabolism: phenylalanine ammonia-lyase (PAL) and 4-coumarate: CoA ligase (4CL), and one representative each from two distinct branch pathways: chalcone synthase (CHS; flavonoids) and S-adenosyl-L-methionine: bergaptol O-methyltransferase (BMT; furanocoumarins). In almost all cases, the relative timing of accumulation differed greatly for mRNA and protein and indicated short expression periods and short half-lives for all mRNAs as compared to the proteins. PAL and 4CL occurred almost ubiquitously in cell type-specific patterns, and their mRNAs and proteins were always coordinately expressed, whereas the cell type-specific localization of flavonoid and furanocoumarin biosynthetic activities was to a large extent mutually exclusive. However, the distribution patterns of CHS and BMT, when superimposed, closely matched those of PAL and 4CL in nearly all tissues analysed, suggesting that the flavonoid and furanocoumarin pathways together consituted a large majority of the total phenylpropanoid biosynthetic activity. Differential sites of synthesis and accumulation indicating intercellular translocation were observed both for flavonoids and for furanocoumarins in oil ducts and the surrounding tissue. The widespread occurrence of both classes of compounds, as well as selected, pathway-specific mRNAs and enzymes, in many cell types of all parsley organs including various flower parts suggests additional functions beyond the previously established roles of flavonoids in UV protection and furanocoumarins in pathogen defence.
Article
To test if secretory canals limit the host ranges of polyphagous moth larvae, we measured the growth of Trichoplusia ni (cabbage looper) and Spodoptera ornithogalli (yellow-striped armyworm) on plants in nine families, including species with and without secretory canals. Larvae were reared to the final instar on excised leaves of the test plant, weighed, then enclosed in the field on either detached leaves with depressurized canals or intact leaves with undamaged canals. After 24 h, the larvae were reweighed and the leaves were examined for evidence of trenching. For comparison, nine additional species of generalist caterpillars were tested on Lactuca serriola (with latex canals) using the same procedure; five of these species were also tested with Petroselinum crispum, which has resin canals.
Article
Five phosphatases were isolated from the latices of three members of the Euphorbiaceae. From Euphorbia lathyris were obtained phosphatases 11 and 12; from E. trigona phosphatase t and from Elaeophorbia drupifera the enzymes d1 and d2. Phosphatases 11, 12 and t were purified to homogeneity. Amino acid compositions are reported and other properties of the enzymes are described. The two enzymes described from E. lathyris both have two pH maxima d(11 at 5.0 and 6.8,12 at 5.8 and 7.5) while t, d1 and d2 respectively have maxima at pHs of 5.6,5.6 and 5.0. On the basis of their responses to several residue-specific inhibitors the five phosphatases apparently comprise three groups: 12 and d1, t and d2, and 11.
Article
Amounts of the sesquiterpene lactones and the major phenolics were determined in the chicory plant at different times during the growing season. The levels of the sesquiterpene lactones (lactucin, lactupicrin and 8-deoxylactucin) and the hydroxycoumarin cichoriin were found to be highest in the most actively growing regions of the plant. In two-choice and no-choice feeding experiments with borosilicate discs, 8-deoxylactucin, lactupicrin and cichoriin significantly reduced feeding of Schistocerca gregaria at levels comparable to those present in the plant. Cichoriin was still significantly antifeedant at 0.006% dry wt, while aesculin, aesculetin and the caffeic acid ester, chicoric acid were inactive. We conclude that the three sesquiterpene lactones secreted in the latex provide a significant barrier to herbivory in chicory, although the phenolics and notably cichoriin also protect the plant from insect feeding.
Article
The alkaloid content in Chelidonium majus has been examined during the day, both in summer and in winter. Sanguinarine, chelidonine, chelerythrine, berberine and coptisine were detected in all parts of the plant. While the berberine content was rather stable, the other alkaloids undergo remarkable daily variations probably due to the combined effect of light and temperature.
Article
Latex-producing plants are widespread in different habitats. Usually these plants secrete an endogenous milk-like fluid in a network of laticifer cells in which sub-cellular organelles intensively synthesize proteins and secondary metabolites. The biological importance of latexes is still unclear and accumulated evidences of their physiological role are still limited. Here laticifer proteins (LP) from Calotropis procera were assayed for insecticidal action against different crop pests in attempt to give new insights for the biological role of latexes. Diets containing 4% LP affected survival (LD50=4.61%) and decreased weight gain (ED50=3.07%) of third instars Ceratitis capitata (Diptera: Tephritidae). Third instars Anticarsia gemmatalis (Lepidoptera: Noctuidae) fed on diets containing 0.1% (w/w) of LP showed reduced body mass while survival was reduced (LD50=0.48%) only for insects grown on 0.5% LP-containing diets. Nonetheless, 1% LP was ineffective against third instars Spodoptera frugiperda (Lepidoptera: Noctuidae). Diets containing 1% LP slightly diminished survival of Dysdercus peruvianus (Hemiptera: Pyrrhocoridae) nymphs while 2% LP was more effective with consistent reduction in bodyweight (ED50=1.4%) observed at the 14th day. Digestive enzymes of gut extracts of D. peruvianus were unable to breakdown LP. On the contrary, heat treated LP was capable of reducing by 50% proteolysis of gut extracts using BANA as substrate suggesting presence of inhibitory activity of cysteine proteinases. Adults of D. peruvianus were not affected when grown in diets containing 1% of LP. Laticifer proteins were shown to possess chitin-binding proteins and chitinolytic activity. Lectin activity was not detected. Occurrence of cysteine proteinase activity already reported in C. procera latex combined with the activities described here could explain, at least in part, the deleterious effects observed.
Article
Cardenolides, free sterols, triacylglycerols, triterpenyl acetates, steryl- and triterpene esters were the major lipid classes in the stem of five- to eight-week-old Asclepias curassavica plants, in which 30% of the cardenolides occurred in the latex. Excised defoliated stems incorporated up to 6.7% of radioactive acetate into these lipids in a three day incorporation period. The label from [2-14C]acetate proceeded mainly to the fatty acid moiety of the triterpene and steryl esters, the fatty acids of the triacylglycerols, the free sterols and the cardenolides. Optimal results were obtained with 10 cm stems from six-week-old plants. An increased supply of acetate (2.5–10 μmol stem−1) showed a saturated synthesis of cardenolides and triacylglycerols and caused an enhanced production of triterpenyl acetates. The highest yield of [14C]cardenolides was obtained after uptake of 5 μmol of acetate per stem. The cardenolide composition of the incubated stem tissue increased on the absorption of 10 μmol of acetate and major changes in organic acid composition were measured after uptake of 20 μmol of acetate. [13C]Uscharidin was biosynthesized from 0.5 mmol of [1,2-13C]acetate by 100 stem tips. 13C NMR spectroscopy showed an unequal relative enrichment in both the genin and the dideoxyhexosulose moiety. The construction of the butenolide ring by the condensation of a pregnane derivative with one molecule acetate as observed for 5β-cardenolides is not confirmed by these-NMR data.
Article
Crude latex sera from 17 members of the genus Euphorbia and from Elaeophorbia drupifera (Euphorbiaceae) contained a wide range of agglutinating abilities. Homogeneous lectins were isolated from latices of Euphorbia coerulescens, E. hermentiana, E. lactea, E. lactea cristata, E. lathyris, E. trigona and Elaeophorbia drupifera. The M,s of the lectins ranged from 60 to 67 000, and the unit weights from 27 to 38 000. pI measurements showed that each latex contained from five to 13 isolectins. The amino acid compositions of the seven lectins were determined: those from E. hermentiana, E. lactea, E. lactea cristata, E. trigona and Elaeophorbia drupifera are related.
Article
Hevains b and l, isolated respectively from the serum and lutoids of freeze-dried latex from Hevea brasiliensis, were purified to homogeneity and compared with hevain a from commercial, ammonia-treated latex. The Mrs of hevains a and b are 69 000 and 58 000, respectively, and both exist in several charged forms. The amino acid compositions of the two enzymes differ significantly, but the reactivities to a variety of ester and protein substrates are similar, as are the pH optima. Hevain l is a distinct protease of Mr 80 000 and unique amino acid composition. It displays esterolytic activity and will digest insulin B chain, but is not proteolytic to azocollagen, azocasein, bovine serum albumen or haemoglobin. The activities of all three enzymes are dependent on the presence of serine and histidine residues.
Article
Partial characterization of the crude proteolytic extracts of five Asclepiadaceae species namely Araujia hortorum Fourn., Asclepias curassavica L., Funastrum clausum (Jacq.) Schlechter, Morrenia brachystephana Griseb. and Morrenia odorata (Hook. et Arn.) Lindley, and a comparison of these results and those from other Asclepiadaceae species are reported. Additionally, the crude extract from M. brachystephana was submitted to further purification and characterization. The crude enzyme showed high proteolytic activity when assayed on casein in the presence of 12 mM cysteine but was strongly inhibited by very low concentrations of sodium iodoacetate (0.01 mM) and mercuric chloride (0.1 mM) suggesting that the enzyme belongs to the cysteinyl-proteases type. Fractioned acetone precipitation followed by cation exchange chromatography allowed the separation of two basic ( pI > 9.3) proteolytically active fractions, both homogeneous by sodium dodecyl sulphate–polyacrylamide gel electrophoresis and with similar molecular masses (25.5 and 26 kDa).Copyright © 1998 John Wiley & Sons, Ltd.
Article
The objective of the present work was to contribute to the understanding of the physiological role of latex lipolytic activity in Euphorbia characias. To this end, the acid and basic lipolytic activity of E. characias latex, as well as the substrate specificity on various triacylglycerols, were measured during the plant's vegetative and reproductive stages. Both activities appeared to increase during the reproductive stage and to peak at the beginning of the vegetative stage, when new leaves and branches are formed. For the first time, the phospholipolytic and esterase activity of E. characias latex is also reported. An extraction method in aqueous medium with the zwitterionic detergent CHAPS was successfully used to extract lipolytic activity from latex. Extraction permitted the selective recovery of a single protein spot, with a molecular weight of 37kDa, and presumably made of several acid isoforms which retained both lipolytic and phospholipolytic activity. The biochemical results suggest that lipolytic and phospholipolytic activity could depend on a single hydrolytic enzyme with several isoforms, equally expressed throughout the biological cycle of the plant. On the basis of the obtained results, we hypothesise that the E. characias latex lipase should be considered as an aspecific acylhydrolase with a combined lipase/phospholipase A activity.
Article
Neuronal tissues from Manduca sexta, the tobacco hornworm, Hyalophora cecropia, the silkmoth and Danaus plexippus, the Monarch Butterfly, contain Na+K+-ATPase which is sensitive to cardiac glycoside (ouabain). The Km for K+ stimulation of Na+K+-ATPase in M. sexta and D. plexippus is 2.2 mM and for Na+ stimulation in D. ple