Arthur G Fett-Neto

Verified

Arthur verified their affiliation via an institutional email.

Learn more

Verified

Arthur verified their affiliation via an institutional email.

Learn more

• Ph.D.
• Full Professor at Federal University of Rio Grande do Sul

Saponins from leaves of Quillaja lancifolia, a native species from southern Brazil, show potent immunoadjuvant activity in experimental vaccine formulations. The accumulation of the immunoadjuvant saponin fraction QB-90 is induced in cultured leaf disks and seedlings by several stresses and stress signaling molecules, such as osmotic agents, salicy...

Green roofs are becoming common in cities around the world. Rooftop vegetation faces severe and unique conditions ranging from shallow substrates, high irradiance, water limitation, flooding, extreme temperatures, and strong winds. To benefit the most from this technology for improving urban climate, ecological interactions, and human life quality,...

The Caatinga biome, which is situated in the interior regions of northeastern Brazil, is a well-defined and recognized ecological zone of semiarid tropical vegetation. It is the largest continuous expanse of seasonally dry tropical forests in South America. Despite its status as a center of endemism and biodiversity, the Caatinga remains among the...

Limited phytodiversity and regeneration rates occur in some of the southern Brazilian formations known as the Myrtacean Woodlands. Data on phytotoxicity, chemical composition, and allelopathic potential of Myrciaria cuspidata O. Berg, a dominant species in such woodlands, is missing. In this study, both the chemical composition and phytotoxic activ...

Schinus terebinthifolius is a medicinal plant with biological in vitro activity against clinically relevant parasites such as Leishmania amazonensis and L. chagasi. Considering its antiparasitic activity, this work aimed to investigate the in vitro effects of S. terebinthifolius fractions against P. falciparum using SYBR fluorescence tests, its cyt...

A simple method set for assessing biochemical changes associated with osmotic stress responses was developed using coffee (Coffea arabica L.) leaf disks. Stress was induced by polyethylene glycol (PEG) exposure. Quantitative evaluation of tissue physiological stress parameters was carried out using analytical methods to validate the conversion of c...

Carvacrol is an antimicrobial agent that shows potential for eliminating microorganisms in vegetables, increasing food safety. However, intense odor and low water solubility of carvacrol are limiting factors for its application for fresh vegetables sanitization, which can be overcome by nanotechnology. Two different nanoemulsions containing carvacr...

Simple Summary Pine forests represent a major source of biomass, including timber and resin. Pine resin constitutes a sustainable source of a myriad of products used in several industrial sectors, such as chemicals, pharmaceuticals, food additives, and biofuels. Every year more than 150,000 tons of resin are tapped from Brazilian plantations. A pin...

Weeds are major threats to the integrity of agricultural and natural environments due to their invasive and competing potential. Bioherbicides are substances based on natural compounds that are biodegradable and often have low residual effects. Plant species able to produce and release phytotoxic compounds may represent effective bioherbicide sourc...

Under natural conditions plants are generally subjected to complex scenarios of combined or sequential environmental stresses. Among the various components of plant biochemistry modulated by abiotic variables, a pivotal role is played by antioxidant systems, including specialized metabolites and their interaction with central pathways. To help addr...

Introduction Selaginellins are specialized metabolites and chemotaxonomic markers for Selaginella species. Despite the growing interest in these compounds as a result of their bioactivities, they are accumulated at low levels in the plant. Hence, their isolation and chemical characterization are often difficult, time consuming, and limiting for bio...

Clonal Eucalyptus propagation is essential for various industry sectors. It requires cuttings to successfully develop adventitious roots (ARs). Environmental conditions are influential on AR development and may be altered to modulate the productivity of hard-to-root clones. The current knowledge gap in research on the physiological patterns underly...

Erythrina velutina is a Brazilian native tree of the Caatinga (a unique semiarid biome). It is widely used in traditional medicine showing anti-inflammatory and central nervous system modulating activities. The species is a rich source of specialized metabolites, mostly alkaloids and flavonoids. To date, genomic information, biosynthesis, and regul...

Complete submergence refers to the situation when floodwaters rise to levels where plants’ shoots and roots are entirely underwater. It can be viewed as a sequence of distinct stressors comprising submergence and de-submergence periods. A plant’s tolerance to this abiotic stress is determined by its ability to acclimate to both phases. Here we aime...

Mimosine is a nonprotein amino acid biosynthesized from OAS (O-acetylserine) and 3H4P (3-hydroxy-4-pyridone or its tautoisomer 3,4-dihydroxypyridine). This amino acid constitutively occurs in all parts of Leucaena leucocephala (Lam.) de Wit plants and is found at higher concentrations in seeds and leaves. This metabolite has several useful activiti...

Among the main features of plant specialized metabolism are cell- and tissue- specific expression and responsiveness to oxidative stress conditions. Although quantitative techniques have significantly improved over time, allowing higher levels of resolution in plant metabolic studies, such analyses are often expensive and/or require relatively larg...

Selaginella convoluta is a Brazilian endemic, desiccation tolerant plant with an effective drought-resistance mechanism. Herein, nuclear magnetic resonance (NMR)-based metabolite profiling was used to investigate this species in different hydration states: dried (harvested in the natural semiarid environment) and after rehydration. NMR is a suitabl...

Herein is presented the descriptive proteome of Erythroxylum pungens (roots, barks, leaves), by label free mass spectrometry (LC-MS/MS), harvested in the natural environment. Processes related to defense were most important in roots while the main protective proteins were diverse among the organs indicating possible different strategies to deal wit...

Saponins are specialized plant terpenoids derived from the mevalonic acid pathway. Triterpenoid saponin cores are decorated with sugar residues, conferring a highly amphipathic nature to these molecules, which show hypocholesterolemic, immunoadjuvant and anti-inflammatory activities, among others. Natural sources of bioactive saponins are relevant...

Introduction: Natural products of pharmaceutical interest often do not reach the drug market due to the associated low yields and difficult extraction. Knowledge of biosynthetic pathways is a key element in the development of biotechnological strategies for plant specialized metabolite production. Erythrina species are mainly used as central nervo...

Adventitious root (AR) development takes place in an intricate cellular environment. Reactive oxygen species (ROS) and antioxidant defenses, triggered by wounding in cuttings, can modulate this process. A comparative assessment of biochemical and anatomical parameters at critical rooting stages in hard- (Eucalyptus globulus Labill.) and easy- (Euca...

Selaginella convoluta is a desiccation tolerant plant native to the Brazilian semiarid region (Caatinga), endowed with an effective drought resistance mechanism. As part of our research efforts to understand the chemical diversity of S. convoluta, dehydrated (harvested in their natural habitat in the dry season) and hydrated (plant acclimated in a...

ABSTRACT Tropane alkaloids are specialized plant metabolites mostly found in the Erythroxylaceae and Solanaceae families. Although tropane alkaloids have a high degree of structural similarity because of the tropane ring, their pharmacological actions are quite distinct. Brazil is one of the main hotspots of Erythroxylum spp. diversity with 123 sp...

In order to meet the growing global demand for bioproducts, areas of forests planted for productive purposes tend to increase worldwide. However, there are several controversies about the possible negative impacts of such forests, such as invasive potential, influence on water balance and biodiversity, and competition with other types of land use....

Plants developed several strategies to cope with ultraviolet radiation (UV) exposure, including accumulation of specialized metabolites, with a recognized major role played by flavonoids. The unique alkaloid brachycerine of Psychotria brachyceras (Rubiaceae) is induced by leaf exposure to high UV intensity and is a potent antioxidant, so it is like...

Adventitious rooting (AR) is an obligatory step for vegetative propagation of commercial woody species. Paper industries have interest in Eucalyptus globulus Labill and its hybrids due to low lignin and lipid contents, which facilitate cellulose extraction. However, this species and some of its hybrids are recalcitrant to rooting, often requiring e...

Passiflora suberosa L. (Passifloraceae) can be found throughout the Americas, and has several medicinal properties, including antioxidant, antibacterial, anti-hemolytic, hypolipidemic, and hypoglycemic activities. Germination rates of P. suberosa are low, even with dormancy breaking treatments, posing an obstacle for its multiplication. Vegetative...

Plants have developed several strategies to overcome the broad scope of environmental challenges imposed by biotic and abiotic stresses, including chemical defenses known as secondary metabolites, natural products or, more recently, specialized metabolites, i.e. chemicals often not present in all plant species, which are mostly involved in ecochemi...

ABSTRACT Psychotria is the largest genus in Rubiaceae. South American species of the genus are promising sources of natural products, mostly due to bioactive monoterpene indole alkaloids they accumulate. These alkaloids can have analgesic, antimutagenic, and antioxidant activities in different experimental models, among other pharmacological proper...

Adventitious roots (ARs) form from above-ground organs, and auxins are major regulators of AR development. TIR1/AFB F-box proteins act as well-established auxin receptors. Auxin transport involves the PINFORMED (PIN) auxin efflux carriers and AUXIN RESISTANT 1/LIKE AUX1 (AUX1/LAX1) influx carriers. To further elucidate the basis of AR development,...

Immunoadjuvant Quillaja spp. tree saponins stimulate both cellular and humoral responses, significantly widening vaccine target pathogen spectra. Host toxicity of specific saponins, fractions and extracts may be rather low and further reduced using lipid-based delivery systems. Saponins contain a hydrophobic central aglycone decorated with several...

To better understand the bases of resin production, a major source of terpenes for industry, the transcriptome of adult Pinus elliottii var. elliottii (slash pine) trees under field commercial resinosis was obtained. Samples were collected from cambium after 5 and 15 days of treatment application, which included tapping followed by application of c...

Pine resin, a natural source of industrially relevant terpenes, is a major non-wood forestry commodity. Resin is obtained by wounding the bark of adult trees and applying stimulant pastes with different adjuvants on the wound. Identifying new adjuvants and high resin producing trees in adult forests often requires long time and intense labor. Micro...

In conifer stems, secretory canals synthesize and store resin for defense against herbivores and pathogens. Resin terpenes are used as raw material by an array of industrial sectors. Most forest stands operationally used in resin extraction are derived from seeds, showing high genetic variation, which reflects in yield. The objective of this study...

Pines constitute a major tree crop, providing an array of products to several industrial sectors, but still holding significant new and unrealized potential worldwide. Among non-wood pine products resin is one of the best known and most exploited. Resin is a complex mixture of terpenes produced by specialized cells dedicated to tree defense. Terpen...

Species of Eucalyptus are some of the most planted trees in the world, providing fiber, cellulose, energy, and wood for construction and furniture in renewable fashion, with the added advantage of fixing large amounts of atmospheric carbon. The efficiency of eucalypts in forestry relies mostly on the clonal propagation of selected genotypes both as...

Mimosine is a non-protein amino acid of Fabaceae, such as Leucaena spp. and Mimosa spp. Several relevant biological activities have been described for this molecule, including cell cycle blocker, anticancer, antifungal, antimicrobial, herbivore deterrent and allelopathic activities, raising increased economic interest in its production. In addition...

Commercially available saponins are extracted from Quillaja saponaria barks, being Quil A® the most widely used. Nanoparticulate immunostimulating complexes (ISCOMs or ISCOMATRIX) formulated with these, are able to stimulate strong humoral and cellular immune responses. Recently, we formulated novel ISCOMs replacing QuilA® by QB-90 (IQB-90), a Quil...

Biomass of pine resin finds several applications in the chemical, pharmaceutical, biofuel and food industries. Resin exudation after injury is a key defense response in Pinaceae since this complex mixture of terpenes has insecticidal, antimicrobial and wound repair properties. Resin yield is increased by effectors applied on the wound area, includi...

Adventitious roots (ARs) emerge from stems, leaves or hypocotyls, being strategic for clonal propagation. ARs may develop spontaneously, upon environmental stress or hormonal treatment. Auxins strongly influence AR development (ARD), depending on concentration and kind. However, the role of different types of auxin is rarely compared at the molecul...

Plant secondary metabolism evolved in the context of highly organized and differentiated cells and tissues, featuring massive chemical complexity operating under tight environmental, developmental and genetic control. Biotechnological demand for natural products has been continuously increasing because of their significant value and new application...

[This corrects the article on p. 849 in vol. 7, PMID: 27379135.].

Pinus elliottii Engelm. (slash pine) is distributed along the maritime coast of Southern Brazil, where it shows invasive pattern and typical allelopathic features. Large quantities of needle litter are produced by pine trees, a biomass that is little explored in areas where this species is alien. Little is known about the dynamics of needle and lit...

Saponin-based adjuvants are promising adjuvants that enhance both humoral and T-cell-mediated immunity. One of the most used natural products as vaccine adjuvants are Quillaja saponaria bark saponins and its fraction named Quil A�. Despite that, its use has been restricted for human use due to safety issues. As an alternative, our group has been st...

Saponin-based adjuvants are promising adjuvants that enhance both humoral and T-cell-mediated immunity. One of the most used natural products as vaccine adjuvants are Quillaja saponaria bark saponins and its fraction named Quil A®. Despite that, its use has been restricted for human use due to safety issues. As an alternative, our group has been st...

The development of adventitious roots is affected by several factors, including the age of the cutting donor plant, which negatively affects rooting capacity. Eucalyptus globulus quickly loses rooting capacity of cuttings as the donor plant ages, although the molecular and biochemical mechanisms behind this process are still unclear. To better unde...

Saponins include a large variety of molecules that find several applications in pharmacology. The use of Quillaja saponaria saponins as immunological adjuvants in vaccines is of interest due to their capacity to stimulate both humoral and cellular responses. The congener species Q. brasiliensis has saponins with chemical similarities and adjuvant a...

Eucalyptus and Populus are among the most economically relevant tree genera. Clonal propagation allows fast genetic gain obtained using elite genotypes. Adventitious rooting (AR), a complex and multifactorial process, is often the main limiting factor for tree cloning. Herein, practical and basic approaches to optimize clonal propagation of eucalyp...

Auxin is critical for plant growth and development. The main natural auxin is indole-3-acetic acid (IAA), whereas 1-naphtalene acetic acid (NAA) is a synthetic form. Auxin Binding Protein 1 (ABP1) specifically binds auxins, presumably playing roles as receptor in non-transcriptional cell responses. ABP1 structure was previously established from mai...

Brachycerine is a shoot monoterpene indole alkaloid with antioxidant, UV protectant, and antimutagenic activities present in Psychotria brachyceras. The alkaloid has been shown to be induced by osmotic stress, UV, heavy metals, and wounding. Since brachycerine accumulation is related to redox imbalance, herein we tested the hypothesis that heat ind...

Triterpene saponins include bioactive compounds with structures consisting of triterpene aglycones (sapogenins) and one or more sugar moieties linked through acetal or ester glycosidic linkages at one or more sites. Centella asiatica (L.) Urban is a medicinal plant that contains bioactive ursane-type saponins, such as madecassoside and asiaticoside...

Alkaloids are one of the largest groups of plant secondary metabolites, being present in several economically relevant plant families. Alkaloids encompass neuroactive molecules, such as caffeine and nicotine, as well as life-saving medicines including emetine used to fight oral intoxication and the antitumorals vincristine and vinblastine. Alkaloid...

Plants from the genus Psychotria include species bearing cyclotides and/or alkaloids. The elucidation of factors affecting the metabolism of these molecules as well as their activities may help to understand their ecological function. In the present study, high concentrations of antioxidant indole alkaloids were found to co-occur with cyclotides in...

Pine oleoresin is a major source of terpenes, consisting of turpentine (mono- and sesquiterpenes) and rosin (diterpenes) fractions. Higher oleoresin yields are of economic interest, since oleoresin derivatives make up a valuable source of materials for chemical industries. Oleoresin can be extracted from living trees, often by the bark streak metho...

Description of target genes used to validate the putative reference genes.

Resin biomass yield estimated as average per streak. Data for winter season based on 80 trees per stimulant paste treatment was used to estimate average resin yield per streak (corresponding to a 15 day period). Different letters indicate significant difference between treatments by Tukey test (P ≤ 0.05).

Specificity of qPCR. (A) Melting curves of the 11 reference genes plus target genes showing a single peak (each representing a technical triplicate). Y-axis: derivative reporter (-Rn) of the melting peak (random units); X-axis: temperature of melting; each vertical line marking the melting peak represents the medium temperature of melting between 8...

Quillaja brasiliensis (Quillajaceae) is a saponin producing species native from southern Brazil and Uruguay. Its saponins are remarkably similar to those of Q. saponaria, which provides most of the saponins used as immunoadjuvants in vaccines. The immunostimulating capacities of aqueous extract (AE) and purified saponin fraction (QB-90) obtained fr...

RNA extraction resulting in good yields and quality is a fundamental step for the analyses of transcriptomes through high-throughput sequencing technologies, microarray, and also northern blots, RT-PCR, and RTqPCR. Even though many specific protocols designed for plants with high content of secondary metabolites have been developed, these are often...

Tapping technique comprises the extraction of pine oleoresin, a non-wood forest product consisting of a complex mixture of mono, sesqui, and diterpenes biosynthesized and exuded as a defense response to wounding. Oleoresin is used to produce gum rosin, turpentine, and their multiple derivatives. Oleoresin yield and quality are objects of interest i...

This volume describes up-to-date techniques for improved production of secondary metabolites of economic interest using field and laboratory methods. Biotechnology of Plant Secondary Metabolism: Methods and Protocols explores different secondary metabolite classes, whole-plant and cell/organ culture systems, and environmental and genetic transforma...

Economically important plant species, such as Eucalyptus globulus, are often rooting recalcitrant. We have previously shown that far-red light enrichment applied to E. globulus donor-plants improved micro-cutting rooting competence and increased rooting zone/shoot carbohydrate ratio. To better understand this developmental response, the relative ex...

Inactivated polio vaccines (IPV) have an important role at the final stages of poliomyelitis eradication programs, reducing the risks associated with the use of attenuated polio vaccine (OPV). An affordable option to enhance vaccine immunogenicity and reduce costs of IPV may be the use of an effective and renewable adjuvant. In the present study, t...

Alkaloids are one of the largest groups of plant secondary metabolites, being present in several economically relevant plant families. Alkaloids encompass neuroactive molecules, such as caffeine and nicotine, as well as life-saving medicines including emetine used to fight oral intoxication and the antitumorals vincristine and vinblastine. Alkaloid...

Araucaria angustifolia is an ancient slow-growing conifer that characterises parts of the Southern Atlantic Forest biome, currently listed as a critically endangered species. The species also produces bark resin, although the factors controlling its resinosis are largely unknown. To better understand this defence-related process, we examined the re...

Saponins are ubiquitous plant natural products, essentially involved in plant defense against biotic stresses, with numerous pharmaceutical and agricultural applications. The common precursor for triterpenoid saponins is squalene (30 carbon molecule) which, via cationic intermediates, is oxidized to 2,3-oxidosqualene. After cyclization, the basic t...

Inactivated polio vaccines (IPV) have an important role at the final stages of poliomyelitis eradication programs, reducing the risks associated with the use of attenuated polio vaccine (OPV). An affordable option to enhance vaccine immunogenicity and reduce costs of IPV may be the use of an effective and renewable adjuvant. In the present study, t...

In previous studies, it has been shown that nitrate supply may favor adventitious rooting in the rooting recalcitrant Eucalyptus globulus. Herein, the impact of various N sources on adventitious rooting and root branching in microcuttings of E. globulus was investigated. The positive effect of nitrate on adventitious root development was confirmed...

A major shoot-specific monoterpene indole alkaloid produced by Psychotria brachyceras, brachycerine, is regulated by either wounding or jasmonate application. Highest concentrations of the alkaloid are found in inflorescences, suggesting a defence role. Brachycerine has antimutagenic and antioxidant properties, capable of quenching singlet oxygen,...

The plant hormone auxin plays a central role in adventitious rooting and is routinely used with many economically important, vegetatively propagated plant species to promote adventitious root initiation and development on cuttings. Nevertheless the molecular mechanisms through which it acts are only starting to emerge. The Arabidopsis superroot2-1...

Saponins are ubiquitous plant natural products, essentially involved in plant defense against biotic stresses, with numerous pharmaceutical and agricultural applications. The common precursor for triterpenoid saponins is squalene (30 carbon molecule) which, via cationic intermediates, is oxidized to 2,3-oxidosqualene. After cyclization, the basic t...

Monoterpene indole alkaloids (MIAs) encompass plant natural products with important pharmacological relevance. They include the anti-tumoral MIAs found in Catharanthus roseus and Camptotheca acuminata. The often low yields of bioactive alkaloids in plants has prompted research to identify the factors regulating MIA production. Oxidative stress is a...

Psychotria brachyceras Muell. Arg. produces the antioxidant monoterpene indole alkaloid (MIA) brachycerine, which, besides retaining a glucose residue, has its terpenoid moiety derived not from secologanin, but probably from epiloganin, representing a new subclass of MIAs. In this work we showed that osmotic stress agents, such as sodium chloride,...