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Biological functions of carotenoids - Diversity and evolution
Abstract
Carotenoids first emerged in archaebacteria as lipids reinforcing cell membranes. To serve this function their long molecules have extremely rigid backbone due to the linear chain of usually 10 to 11 conjugated C=C bonds in trans-configuration — the length corresponding the thickness of hydrophobic zone of membrane which they penetrate as “molecular rivets”. Carotenoids retain their membrane-reinforcing function in some fungi and animals.
The general structure of carotenoid molecule, originally having evolved for mechanical functions in membranes, possess a number of other properties that were later used for independent functions. The most striking fact is that these properties proved to fit some new functions to perfection.
— The polyene chain of 9—11 double bonds absorbs light precisely in the gap of chlorophyll absorption — function as accessory light-harvesting pigments in all plants;
— Unique arrangement of electronic levels owing to the by polyene chain structure makes carotenoids the only natural compounds capable of excitation energy transfer both (i) from carotenoid excited state to chlorophyll in the light-harvesting complex and (ii) from triplet chlorophyll or singlet oxygen to carotenoid in photosynthetic reaction centers — protection of RC from photodamage.
The linear system of conjugated C=C bonds provides high reducing potential of carotenoid molecules making them potent antioxidants in lipid formations. Still, there is a lack of evidence of the chemical antioxidant function of carotenoids, especially in higher organisms; most data demonstrate an antioxidant ability rather than a function.
Carotenoids have many other independent biological functions, including: specific coloration patterns in plants and animals, screening from excessive light and spectral filtering, defense of egg proteins from proteases in some invertebrates; the direct carotenoid derivative — retinal — acts as visual pigment in all animals and as chromophore in bacteriorhodopsin photosynthesis, retinoic acid in animals and abscisic acid in plants serve as hormones. All these functions utilize various properties (mechanical, electronic, stereospecific) of a single structure evolved in bacteria for a single membrane-reinforcing function, thus demonstrating an example of pure evolutionary preadaptation.
One of the practical conclusions that can be reached by reviewing uniquely diverse properties and functions of carotenoids is that, when considering possible mechanisms of their effects in organisms (e.g., anticarcinogenic action), all their functional traits should be taken into account.
... This groups of about 600 members and it can be generally divided into two subgroups, carotenes (C 40 H 56 ) and xanthophylls (C 40 H 56 O 2 or C 40 H 56 O), which differ in the terminal rings and oxygenation. Carotenoids are fat-soluble in nature [7][8][9] . Phytoene, the first true carotenoid, is produced by the enzyme phytoene synthase condensation of two molecules of geranyl diphosphate. ...
... Consumption of meals rich in carotenoids also has preventive and protective effects on an individual's health. Other active substances found in vegetables such as tomatoes include neoxanthin, lutein, β-cryptoxanthin, αcarotene, cyclolycopene, and 6-epoxide [8][9][10] . Certain carotenoids are also present in green leafy vegetables and numerous coloured fruits, although their colours are typically latent by those of other predominant pigments when they are present in relatively small amounts. ...
... Mainly anthocyanins are present in nature and the heterosides form [14] . Anthocyanins are synthesized in the cytosol, glycosylated, acylated, and accumulated in vacuoles as anthocyanin products [9,14] . ...
Plant pigments are one of the main groups of vegetal active principles,
with the most crucial therapeutic role. Plant pigments have vital role in the
maintenance of human health as well as in the environmental parameters.
The major plant pigments are chlorophylls, carotenoids, flavonoids,
anthocyanins and betalains. During photosynthesis, green coloured pigment
chlorophyll plays a major role. Each class of the pigments contain various
chemical components with distinct subgroups. Plant pigments are acting as
anti-cancer, anti-inflammatory, anti-diabetic, hepato-protective, anti-obesity, anti-allergic, cardiovascular protective, antimicrobial and antioxidant agent. Heavy metals and secondary air pollutants may have an impact on plant
growth, reproduction and development mechanism. Excessive fertiliser use
in crop cultivation and management may result in heavy metal build up,
eutrophication, phosphate and nitrate accumulation in agriculture field.
Excess inorganic or heavy metals also pose a risk to water purity.
Chlorophyll, the green photosynthetic pigment can act as important bioindicator or bio-monitoring agent of air pollution. Policies and rules that
encourage the effective and eco-friendly utilization of fertilisers and their
supply can improve soil and water quality while avoiding negative impacts
on human health. It may also assure to improve the air quality in the entire
biotic and abiotic environment.
... Beta Carotene, Lutein, and Zeaxanthin are among the most studied carotenoids. Beta Carotene, being the most abundant in the human diet, blood, and tissues, belongs to the class of carotenoids called carotenes, which contain only carbon and hydrogen atoms [23,24] Lutein and Zeaxanthin, on the other hand, are members of a class of carotenoids called xanthophylls. They have one hydroxyl group and are more polar than carotenes [16]. ...
... This is in addition to their potent antioxidant properties [4,26]. Carotenoids are, in general, not water-soluble, but are very fat-soluble compounds, and in the blood stream are transported by the low-density lipoproteins (LDL) and high-density lipoproteins (HDL) [23,24], which in turn are bound by albumin [24][25][26][27]. Serum albumin is the predominant protein found in the blood stream and is responsible for transporting important substances, such as hormones and carotenoids, through the body [27,28]. ...
... This is in addition to their potent antioxidant properties [4,26]. Carotenoids are, in general, not water-soluble, but are very fat-soluble compounds, and in the blood stream are transported by the low-density lipoproteins (LDL) and high-density lipoproteins (HDL) [23,24], which in turn are bound by albumin [24][25][26][27]. Serum albumin is the predominant protein found in the blood stream and is responsible for transporting important substances, such as hormones and carotenoids, through the body [27,28]. ...
Carotenoids are naturally abundant, fat-soluble pigmented compounds with dietary, antioxidant and vision protection advantages. The dietary carotenoids, Beta Carotene, Lutein, and Zeaxanthin, complexed with in bovine serum albumin (BSA) in aqueous solution, were explored using Raman spectroscopy to differentiate and quantify their spectral signatures. UV visible absorption spectroscopy was employed to confirm the linearity of responses over the concentration range employed (0.05–1 mg/mL) and, of the 4 Raman source wavelengths (785 nm, 660 nm, 532 nm, 473 nm), 532 nm was chosen to provide the optimal response. After preprocessing to remove water and BSA contributions, and correct for self-absorption, a partial least squares model with R2 of 0.9995, resulted in an accuracy of the Root Mean Squared Error of Prediction for Beta Carotene of 0.0032 mg/mL and Limit of Detection 0.0106 mg/mL. Principal Components Analysis clearly differentiated solutions of the three carotenoids, based primarily on small shifts of the main peak at ~1520 cm−1. Least squares fitting analysis of the spectra of admixtures of the carotenoid:protein complexes showed reasonable correlation between norminal% and fitted%, yielding 100% contribution when fitted with individual carotenoid complexes and variable contributions with multiple ratios of admixtures. The results indicate the technique can potentially be used to quantify the carotenoid content of human serum and to identify their differential contributions for application in clinical analysis.
... All carotenoids possess light-harvesting and photoprotection properties due to conjugated double bonds, which can exhibit π → π* transition following light-absorption and subsequent high-energy excitation [39]. This light-harvesting property of carotenoids increases the spectral range of photosynthesis in plants [40]. Besides, light absorption and excitation result in color formation and carotenoids exhibit yellow-orange or red color, which are in the visible spectrum with wavelengths 400-500 nm [39]. ...
... In addition, the linear system of conjugated C-C double bonds renders carotenoids potent antioxidants via high reducing potential in lipid formation via oxidation. When carotenoid molecules interact with membranes or dissolve in lipid structures, they can protect these structures from oxidative damage caused by aggressive radical species, thereby preventing irreversible destruction [40]. The effective neutralization of reactive oxygen species and other free radicals by carotenoids in both photosynthetic and non-photosynthetic organisms provides protection from oxidative damage. ...
Carotenoids are natural products found in photosynthetic organisms such as plants, algae, and some bacteria species. Humans and animals cannot synthesize carotenoids, and they obtain these molecules through their diet. The common structure of carotenoids contains conjugated double bonds that provide color formation in the visible spectrum, at 400–500 nm. In photosynthetic organisms, carotenoids contribute to color formation for various purposes, such as sex selection, protection from predators, and light-harvesting to increase the spectral range of photosynthesis. The conjugated double bonds not only provide color formation but also provide antioxidant properties to carotenoid molecules. Studies have shown that carotenoids are capable of scavenging free radicals and reactive oxygen species, as well as quenching singlet oxygen molecules. The antioxidant power of carotenoids results in several health benefits. These include anticancer, neuroprotective, and anti-atherosclerotic activities. This chapter aims to review the antioxidant activities and health benefits of major carotenoids, beginning with their structure and synthesis, and also discussing their natural sources.
... Carotenoids encompass a diverse spectrum of organic pigments, ranging from yellows to brilliant oranges and deep reds [1,2]. These compounds offer more than just coloration; they act as precursors to several hormones and play multiple biological roles, including light-harvesting, photoprotection, and providing distinct hues to various organisms [3][4][5][6][7][8][9][10]. From a biotechnological perspective, specific carotenoids such as β-carotene, lycopene, and lutein have predominantly served as food colorants, antioxidants, and essential components in animal feed [11][12][13]. ...
... These compounds offer more than just coloration; they act as precursors to several hormones and play multiple biological roles, including light-harvesting, photoprotection, and providing distinct hues to various organisms [3][4][5][6][7][8][9][10]. From a biotechnological perspective, specific carotenoids such as β-carotene, lycopene, and lutein have predominantly served as food colorants, antioxidants, and essential components in animal feed [11][12][13]. In addition to their conventional applications, these pigments have found practical uses in the fields of nutraceuticals, cosmetics, and pharmaceuticals [8,14,15]. The marine environment, abundant with diverse microorganisms, holds significant potential for the exploration of novel carotenoid-producing organisms. ...
Carotenoids, biotechnologically significant pigments, play crucial biological roles in marine microorganisms. While various environments have been explored to understand the diversity of carotenoids and their biosynthesis, the Antarctic Ocean remains relatively under-investigated. This study conducted a metagenomic analysis of seawater from two depths (16 and 25 m) near the King Sejong Station in the Antarctic Ocean. The analysis revealed a rich genetic diversity underlying C40 (astaxanthin, myxol, okenone, spheroidene, and spirilloxanthin), C30 (diaponeurosporene, diapolycopene, and staphyloxanthin), and C50 (C.p. 450) carotenoid biosynthesis in marine microorganisms, with notable differential gene abundances between depth locations. Exploring carotenoid pathway genes offers the potential for discovering diverse carotenoid structures of biotechnological value and better understanding their roles in individual microorganisms and broader ecosystems.
... Carotenoids are a family of pigmented compounds that are synthesized by plants and microorganisms but not animals. In plants, they contribute to the photosynthetic machinery and protect them against photo-damage (Alexander, 1999). Carotenoids are notable for their wide distribution, structural diversity, and of various functions (Kimura and Rodriguez-Amaya, 2004). ...
... They are the most ubiquitous and wide spread class of natural fatsoluble pigments. Carotenoids are present as microcomponents in fruits and vegetables and are responsible for their yellow, orange and red colours (Alexander, 1999). Carotenoids are made up of a polyisoprenoid structure, a long conjugated chain of double bond and a near bilateral symmetry around the central double bond, as common chemical features (Briton, 1995). ...
Ten different locally grown and widely consumed vegetables were selected for the screening of total carotenoids and β-carotene contents. The pigments were extracted by solvent extraction and the concentrations determined using UV-visible spectrophotometer. Carrot (Daucus carota) has the highest values of both the total carotenoids (397.8 ± 2.0 µg/g) and β-carotene (203.0 µg/g). Squash (C. moschata) has the lowest concentrations of total carotenoids (20.3 ± 2.0 µg/g) while cabbage has the lowest β-carotene (24.41 ± 9.8 µg/g). These vegetables, if properly processed, may serve as good sources of provitamin A in addition to other nutritional roles. The potentials of these vegetables as candidates for biofortification with β-carotene for the eradication of vitamin A deficiency were discussed.
... It also exposes hydroxylated derivates to the cytosol and outside cell membrane, providing excellent antioxidant localization. This membrane biophysical property can also partially explain the several roles that carotenoids play in mammals (e.g., in the retina and brain) [22,23]. rivets", Figure 2). ...
... It also exposes hydroxylated derivates to the cytosol and outside cell membrane, providing excellent antioxidant localization. This membrane biophysical property can also partially explain the several roles that carotenoids play in mammals (e.g., in the retina and brain) [22,23]. Although animals cannot synthesize ASX, its intake through microalgae is responsible for the dark red color found in many forms of marine life (e.g., fish eggs, shrimp, lobster, salmon, etc.). ...
A healthy lifestyle is essential for maintaining physical and mental health. Health promotion, with a particular emphasis on regular exercise and a healthy diet, is one of the emerging trends in healthcare. However, the way in which exercise training and nutrients from dietary intake interact with each other to promote additive, synergistic, or antagonistic effects on physiological functions leading to health promotion, and the possible underlying biomolecular mechanisms of such interactions, remain poorly understood. A healthy diet is characterized by a high intake of various bioactive compounds usually found in natural, organic, and fresh foodstuffs. Among these bioactive compounds, astaxanthin (ASX), a red carotenoid pigment especially found in seafood, has been recognized in the scientific literature as a potential nutraceutical due to its antioxidant, anti-inflammatory, and neurotrophic properties. Therefore, scientists are currently exploring whether this promising nutrient can increase the well-known benefits of exercise on health and disease prevention. Hence, the present review aimed to compile and summarize the current scientific evidence for ASX supplementation in association with exercise regimes, and evaluate the additive or synergistic effects on physiological functions and health when both interventions are combined. The new insights into the combination paradigm of exercise and nutritional supplementation raise awareness of the importance of integrative studies, particularly for future research directions in the field of health and sports nutrition science.
... However, the discoloration observed in response to host separation may be primarily due to a lack of pigments obtained through feeding or through the host's chemical environment. As carotenoids are involved in various functions of metabolism (Matsuno 2001;Vershinin 1999;Wade et al. 2017), symbionts may reuse them to more fundamental functions leading to an overall depigmentation of the organisms. But as often in complex and dynamic environmental systems, it is evident that the observed color variations in these symbionts are influenced by a combination of factors, including perhaps hormonal regulation, neuronal regulation, and direct impacts on pigment metabolism. ...
In marine ecosystems, organisms often form enduring associations with other species, creating rich symbiotic communities within benthic hosts. Among these associations, mimetic pigmentation—where symbionts adopt colors resembling their hosts—plays a key role in predator avoidance strategies. Despite its prevalence, this phenomenon remains poorly understood. This research aims to explore pigmentation dynamics in four symbiotic pairs: (i) Zenopontonia soror with Culcita novaeguineae, (ii) Synalpheus stimpsonii with Phanogenia distincta, and (iii) Tuleariocaris holthuisi, and (iv) Arete indicus with Echinometra mathaei. The study involves monitoring symbiont survivability, standardized photography to measure color variation, histological analysis to locate pigment-associated cells, and HPLC (High Performance Liquid Chromatography) to characterize pigment chemical composition. Results indicate a strong host dependency for all symbionts, with three species showing reliance on host metabolites. Host-symbiont separation affects symbiont pigmentation, leading to dynamic color changes. Histological analysis reveals chromatophores in all species, with A. indicus exhibiting two distinct layers of chromatophores containing different pigments. Chemical analysis shows differences in pigments between partners, with carotenoids detected in both Z. soror and C. novaeguineae, while S. stimpsonii and P. distincta show carotenoids predominantly in the symbiont. These findings enhance our understanding of mimetic coloration mechanisms in symbiotic shrimps, advancing knowledge of symbiont ecology and host interactions.
... Carotenoids are potent lipophilic antioxidants due to the linearly conjugated carbon bonds that provide high reduction potential [59]. The characteristic color of carotenoids, varying from yellow to red, is due to a polyene chain with several conjugated double bonds that function as a chromophore [60]. ...
Carrot waste is a rich source of pro-vitamin A, β-carotene, recognized for its immunomodulatory and health-promoting properties. The present study was aimed at formulating an innovative table spread (ITS) enriched with concentrated carotenoid extract derived from carrot pomace. Prior extraction of carotenoids in flaxseed oil was optimized resulting in extract (CE) rich in carotenoids (82.66 µg/g) and alpha-linolenic acid (ALA). The effects of three ingredients i.e. CE, tri-sodium citrate (TC), and common salt (CS) on ITS formulated using 33 factorial experiment (27 treatment combinations) were determined employing three-way ANOVA of Proc GLM method of SAS 9.3 for its textural and sensory acceptability. The optimized formulation contained 15% CE, 1.0% CS and 0.3% TC. ITS displayed medium (≈51% fat) internal phase emulsion (confirmed via fluorescence microscopy) stabilized (-56.867 mV ± 0.850 zeta potential) by whey protein concentrate and possessed high thermal stability (studied through thermogravimetric analysis). The control table spread (CTS) was prepared using all ingredients except CE replaced with flaxseed oil. ITS showed significantly (p < 0.05) higher carotenoid, antioxidant (ABTS, DPPH and FRAP), yellowness index and b* value than CTS; while non-significant (p > 0.05) difference existed for proximate composition and acidity. ITS turned out to be a naturally colored functional product and excellent source of carotenoids (24.276 μg/g ± 0.076) and ALA (13.816 g/ 100 g fat).
... Carotenoids are common and diverse organic compounds [1]. Some carotenoids have essential functional roles in animals [2], such as in the visual and immune systems, diapause-related processes, protection against oxidative stress, ornament-based signaling, etc. [3][4][5][6]. However, the specific carotenoid composition in most animals and the function and metabolism of most carotenoids are largely unknown. ...
Carotenoids are common and diverse organic compounds with various functional roles in animals. Except for certain aphids, mites, and gall midges, all animals only acquire necessary carotenoids through their diet. The house fly (Musca domestica) is a cosmopolitan pest insect that populates diverse habitats. Its larvae feed on organic substrates that may vary in carotenoid composition according to their specific content. We hypothesized that the carotenoid composition in the adult house fly’s body would reflect the carotenoid composition in the larval feed. House fly larvae were reared on diets that differed in carotenoid composition. HPLC analysis of the emerging adult flies indicate that the carotenoid composition of adult house flies is related, but not identical, to the carotenoid composition in its natal substrate. These findings may be developed to help identify potential sources of house fly infestations. Also, it is recommended that rearing substrates of house fly larvae, used for animal feed, should be carefully considered.
... Carotenoids can assist with photoprotection against UV damage and stabilize protein structures (Brunet et al., 2011). Carotenoids also play a critical role in mitigating the symptoms of a number of cancers, premature aging, cardiovascular diseases, and arthritis due to their anti-oxidant properties (Chen et al., 2017;Vershinin, 1999). ...
... Carotenoids are common and diverse organic compounds [1]. Some carotenoids are known to have essential functional roles in animals [2], such as in the visual and immune systems, diapauserelated processes, protection against oxidative stress, ornament-based signaling, etc. [3][4][5][6]. However, the specific carotenoid composition in most animals and the function and metabolism of most carotenoids are largely unknown. ...
Carotenoids are common and diverse organic compounds with various functional roles in ani-mals. Except for certain aphids, mites, and gall midges, all animals acquire necessary carotenoids only through their diet. The House fly (Musca domestica) is a cosmopolitan pest insect that populates diverse habitats. Its larvae feed on organic substrates that may vary in carotenoid composition according to their specific content. We hypothesized that the carotenoid composition in the adult House fly’s body would reflect its composition in the larval feed. We reared house fly larvae on substrates that differed in carotenoid composition and characterized the carotenoid composition of the emerging adults. Our results indicate that the carotenoid composition of adult House flies is related to the carotenoid composition in its natal substrate, but does not directly reflect it. We suggest that these findings may be developed to identify sources of House fly in-festations. We also recommend that care should be taken when considering the rearing substrates of House fly larvae used for animal feed.
... The capacity of carotenoids to cross the blood-brain barrier (BBB) is, to some extent, contingent upon factors such as the specific carotenoids, their concentration, and the overall health and integrity of the BBB, thereby exhibiting variability [61,62]. Given the significance of carotenoids in neuronal protection against oxidative stress and inflammation, which are implicated in the development and progression of Alzheimer's disease, it is imperative to conduct comprehensive research to fully understand their mechanism of action and therapeutic potential in this specific context. ...
Tetraselmis chuii is an EFSA-approved novel food and dietary supplement with increasing use in nutraceutical production worldwide. This study investigated the neuroprotective potential of bioactive compounds extracted from T. chuii using green biobased solvents (ethyl acetate, AcOEt, and cyclopentyl methyl ether, CPME) under pressurized liquid extraction (PLE) conditions and supercritical fluid extraction (SFE). Response surface optimization was used to study the effect of temperature and solvent composition on the neuroprotective properties of the PLE extracts, including anticholinergic activity, reactive oxygen/nitrogen species (ROS/RNS) scavenging capacity, and anti-inflammatory activity. Optimized extraction conditions of 40 °C and 34.9% AcOEt in CPME resulted in extracts with high anticholinergic and ROS/RNS scavenging capacity, while operation at 180 °C and 54.1% AcOEt in CPME yielded extracts with potent anti-inflammatory properties using only 20 min. Chemical characterization revealed the presence of carotenoids (neoxanthin, violaxanthin, zeaxanthin, α- and β-carotene) known for their anti-cholinesterase, antioxidant, and anti-inflammatory potential. The extracts also exhibited high levels of omega-3 polyunsaturated fatty acids (PUFAs) with a favorable ω-3/ω-6 ratio (>7), contributing to their neuroprotective and anti-inflammatory effects. Furthermore, the extracts were found to be safe to use, as cytotoxicity assays showed no observed toxicity in HK-2 and THP-1 cell lines at or below a concentration of 40 μg mL−1. These results highlight the neuroprotective potential of Tetraselmis chuii extracts, making them valuable in the field of nutraceutical production and emphasize the interest of studying new green solvents as alternatives to conventional toxic solvents.
... The clearest function of these molecules is their antioxidant activity [11], where the conjugated double bond structure serves to buffer the activity of high energy electrons found in free radicals. In addition, several studies have reported that bacterial carotenoids are involved in the mechanism of cold adaptation for some bacteria [48,49], and their production is associated with the modulation of physical membrane properties such as acyl chain fluidity based on measurements of lipid bilayer core dynamics through DPH anisotropy [13,50], leading to changes in membrane rigidity [11] and resistance to antimicrobial peptides [11]. ...
Staphylococcus aureus is an opportunistic pathogen that is considered a global health threat. This microorganism can adapt to hostile conditions by regulating membrane lipid composition in response to external stress factors such as changes in pH and ionic strength. S. aureus synthesizes and incorporates in its membrane staphyloxanthin, a carotenoid providing protection against oxidative damage and antimicrobial agents. Staphyloxanthin is known to modulate the physical properties of the bacterial membranes due to the rigid diaponeurosporenoic group it contains. In this work, preparative thin layer chromatography and liquid chromatography mass spectrometry were used to purify staphyloxanthin from S. aureus and characterize its structure, identifying C15, C17 and C19 as the main fatty acids in this carotenoid. Changes in the biophysical properties of models of S. aureus membranes containing phosphatidylglycerol, cardiolipin, and staphyloxanthin were evaluated. Infrared spectroscopy shows that staphyloxanthin reduces the liquid-crystalline to gel phase transition temperature in the evaluated model systems. Interestingly, these shifts are not accompanied by strong changes in trans/gauche isomerization, indicating that chain conformation in the liquid-crystalline phase is not altered by staphyloxanthin. In contrast, headgroup spacing, measured by Laurdan GP fluorescence spectroscopy, and lipid core dynamics, measured by DPH fluorescence anisotropy, show significant shifts in the presence of staphyloxanthin. The combined results show that staphyloxanthin reduces lipid core dynamics and headgroup spacing without altering acyl chain conformations, therefore decoupling these normally correlated effects. We propose that the rigid diaponeurosporenoic group in staphyloxanthin and its positioning in the membrane is likely responsible for the results observed.
... Significant reduction in chlorophyll content has also been reported by Cha-um and Kirdmanee (2012) in Eucalyptus camaldulensis with increase in salt concentration (2%). Carotenoids play a crucial role in plants as antioxidants and protect the chlorophyll pigment from photo damage (Alexander, 1999;Havaux, 2014). Santos and Silva (2015) emphasized that the degradation of carotenoid pigments interferes in the photo-protection exerted by the plants and thus, increases the chances of photo-oxidation under salinity stress. ...
The aim of the study was to assess and quantify the impact of salt stress on key morpho-physiological traits that influence biomass production in Salix clones. In February 2021, a pot experiment was conducted using stem cuttings of five selected Salix clones. The experiment followed a Factorial Completely Randomized Design (CRD) with four replications. The clones were subjected to different levels of NaCl treatments (0, 20, 40, 60, and 80 mM) during the active growth period. The observations on growth and physiological characteristics of clones were recorded at an interval of two months after initiation of salinity treatments i.e., May, July and October. However, the biomass parameters were recorded at the end of experiment. All the growth and biomass traits showed significant reduction with increase in salinity treatments. Among physiological traits significant reduction were observed in total chlorophyll, carotenoids and relative water content, while salinity stress raised the content of proline, total soluble sugar, total soluble protein and Na ⁺ /K ⁺ ratio in all the clones. The enzymatic activities of POD and SOD increased in all the clones when subjected to higher levels of salinity stress. On the basis of overall mean performance, clone UHF-03 showed optimum growth and biomass accumulation at 80 mM and was found to be the most tolerant to salinity stress. SEM and EDS mapping confirmed anatomical changes and Na accumulations in the roots and leaves of Salix in response to salinity stress.
... Pigments containing polyene chains are widespread in nature [16]. Carriers include phytoplankton, calcareous skeletons such as some mollusc shells, vegetables such as carrots, bird feathers and even macular pigments of the human retina [17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36]. The vast majority of these pigments belong to the carotenoid family. ...
Pearls, a well-known organic gemstone, are popular for their attractive lustre and rich colour. The pigmentation and colour of pearls have never been clearly explained. Understanding the pigments and colour origin of pearls can be a guide for artificial cultivation and rational conservation. In this study, Chinese freshwater cultured pearls were collected as research samples. The appearance and colour characteristics of pearls were characterised using D65 standard light source photography and UV–Vis spectroscopy, the molecular structure of the pigments in the pearls was characterised using Raman spectroscopy, and Density Functional Theory (DFT) calculations were used to reveal the characteristics of the pigments in the pearls in terms of molecular structure and electronic excitation. It was proposed that freshwater pearls are coloured with polyene pigments, with the chain length of the polyene determining the type of colour and the concentration of the polyene determining the colour intensity of the pearl. The HOMO–LUMO transition of conjugated polyenes is intrinsically responsible for the colour of pearls. Many colour-rich biominerals also have similar Raman spectral features to pearls, and this study has wider implications for understanding the nature of pigments and their colour origins.
... Our results agree with several reports of decrease content of chlorophyll and carotenoids by salinity as reported in a number of glycophytes. Carotenoidplays an important role in plants as antioxidants and protects chlorophyll pigment from photo damage [16]. Havaux [17] studied a new function of carotenoid, which relates to the response of plants to environmental stresses. ...
Over the past several decades, the southwest zone of Punjab is encountering various problems such as waterlogging, high use of surface canal water for irrigation and swift rise in water demand lead to stagnation in saline zone due to salinity ingression. Due to salinization, most of crops failed to grow, therefore, identification of salt tolerant plants and to check the level of tolerance to salinity in order to prevent mortality plants in salt affected areas is highly required for environment sustainability. To understand these salinity issues, the present study was conducted at Punjab Agricultural University to screen four ornamental summer season annual species suitable for salt affected areas of Punjab. Selection of plant species was done on the basis of physiological changes in plant leaves. The one month old seedlings of four different annual species were grown in 8 inch earthen pots were exposed to five different concentrations of sodium chloride salinity stress (control, 30, 60, 90, and 120 mM). The factorial completely randomized block design was followed in the experiment with three replicates in each treatment. The physiological parameters viz., chlorophyll, carotenoid, relative leaf water content, electrolyte leakage and proline content were calculated to depict the salt tolerant ornamental summer season annual species. It has been concluded on the basis of physiological response, the maximum salt tolerance was observed in P. grandiflora followed by B. scoparia, T. erecta and Z. elegans.
... Microbial cell factories have been widely used to produce diverse natural products, because of their advantages of a short production period, environmentally friendly processes, and their ability to utilize sustainable resources [1,2]. Carotenoids are one of the most important classes of natural pigments with important physiological functions and diverse potential applications [3,4]. The production of carotenoids using metabolically engineered microorganisms has attracted much attention as an alternative route to the current processes of extraction from natural sources and chemical synthesis. ...
Background
Xanthophylls are a large class of carotenoids that are found in a variety of organisms and play particularly important roles in the light-harvesting and photoprotection processes of plants and algae. Violaxanthin is an important plant-derived xanthophyll with wide potential applications in medicines, foods, and cosmetics because of its antioxidant activity and bright yellow color. To date, however, violaxanthins have not been produced using metabolically engineered microbes on a commercial scale. Metabolic engineering for microbial production of violaxanthin is hindered by inefficient synthesis pathway in the heterologous host. We systematically optimized the carotenoid chassis and improved the functional expression of key enzymes of violaxanthin biosynthesis in Escherichia coli.
Results
Co-overexpression of crtY (encoding lycopene β-cyclase), crtZ (encoding β-carotene 3-hydroxylase), and ZEP (encoding zeaxanthin epoxidase) had a notable impact on their functions, resulting in the accumulation of intermediate products, specifically lycopene and β-carotene. A chassis strain that did not accumulate the intermediate was optimized by several approaches. A promoter library was used to optimize the expression of crtY and crtZ. The resulting strain DZ12 produced zeaxanthin without intermediates. The expression of ZEP was further systematically optimized by using DZ12 as the chassis host. By using a low copy number plasmid and a modified dithiol/disulfide system, and by co-expressing a full electron transport chain, we generated a strain producing violaxanthin at about 25.28 ± 3.94 mg/g dry cell weight with decreased byproduct accumulation.
Conclusion
We developed an efficient metabolically engineered Escherichia coli strain capable of producing a large amount of violaxanthin. This is the first report of a metabolically engineered microbial platform that could be used for the commercial production of violaxanthin.
... The polarity of carotenoids is altered when polar functional groups are attached to the polyene chain, which might influence the localization of carotenoids within biological membranes and their interactions with other molecules [39]. Vershinin [40] reported that in primitive organisms, carotenoids reinforced lipids in the cell membrane. The study also inferred that the levels of carotenoids controlled the stability of the membrane (which is liable to change with temperature) and, thus, affected the functions of membranes. ...
Background
Low temperatures greatly limit the growth of microorganisms. Low-temperature adaptation in microorganisms involves multiple mechanisms. Carotenoids are naturally occurring lipid-soluble pigments that act as antioxidants and protect cells and tissues from the harmful effects of free radicals and singlet oxygen. However, studies on the regulation of carotenoid biosynthesis at low temperatures in microorganisms are limited. In this study, we investigated the correlation between carotenoids and low-temperature adaptation in the cold-adapted strain of Rhodosporidium kratochvilovae YM25235.
Results
Carotenoid biosynthesis in YM25235 was inhibited by knocking out the bifunctional lycopene cyclase/phytoene synthase gene ( RKCrtYB ) using the established CRISPR/Cas9 gene-editing system based on endogenous U6 promoters. The carotenoids were extracted with acetone, and the content and composition of the carotenoids were analyzed by spectrophotometry and HPLC. Then, the levels of reactive oxygen species (ROS) and the growth rate in YM25235 were determined at a low temperature. The results indicated that the carotenoid biosynthesis and ROS levels were increased in the YM25235 strain at a low temperature and inhibition of carotenoid biosynthesis was associated with higher ROS levels and a significant decrease in the growth rate of YM25235 at a low temperature.
Conclusions
The regulation of carotenoid biosynthesis was associated with low-temperature adaptation in YM25235. Our findings provided a strong foundation for conducting further studies on the mechanism by which YM25235 can adapt to low-temperature stress.
... Carotenoids are membrane-stabilizing chemicals recruited as photoprotective pigments during photosynthesis. According to their chemical structure, carotenoids are classified as isoprenoid polyenes, which are lipid-soluble, yellowish-orange pigments and are biosynthesized by algae, plants, and certain microbes [164,165]. Carotenoids including astaxanthin, β-carotene, β-cryptoxanthin, crocin, fucoxanthin, lutein, and lycopene are the most common plant pigments that play key roles in the prevention and treatment of several diseases, including cancer [166]. Zhang et al. explored the anti-proliferative activities of four different carotenoids β-carotene, astaxanthin, capsanthin, and bixin on K652 leukemia cancer cells. ...
Human nuclear receptors (NRs) are a family of forty-eight transcription factors that modulate gene expression both spatially and temporally. Numerous biochemical, physiological, and pathological processes including cell survival, proliferation, differentiation, metabolism, immune modulation, development, reproduction, and aging are extensively orchestrated by different NRs. The involvement of dysregulated NRs and NR-mediated signaling pathways in driving cancer cell hallmarks has been thoroughly investigated. Targeting NRs has been one of the major focuses of drug development strategies for cancer interventions. Interestingly, rapid progress in molecular biology and drug screening reveals that the naturally occurring compounds are promising modern oncology drugs which are free of potentially inevitable repercussions that are associated with synthetic compounds. Therefore, the purpose of this review is to draw our attention to the potential therapeutic effects of various classes of natural compounds that target NRs such as phytochemicals, dietary components, venom constituents, royal jelly–derived compounds, and microbial derivatives in the establishment of novel and safe medications for cancer treatment. This review also emphasizes molecular mechanisms and signaling pathways that are leveraged to promote the anti-cancer effects of these natural compounds. We have also critically reviewed and assessed the advantages and limitations of current preclinical and clinical studies on this subject for cancer prophylaxis. This might subsequently pave the way for new paradigms in the discovery of drugs that target specific cancer types.
... In addition, depressed patients exhibit a dysregulation in brain retinoid [87,88]. Interestingly, ABA and RA are carotenoid derivatives [7,89], and both molecules share a similar structure, specially a key carboxyl group in the isoprene-composed side chain involved in their bioactivity [84,90]. ...
The plant hormone Abscisic Acid (ABA) has applications not only in agriculture, but also in human health. ABA is established as the key hormonal regulator of plant stress physiology, and it is also involved in plant growth and development under normal conditions. This phytohormone is present in the human body from dietary sources as well as from endogenous production through the carotenoid biogenesis pathway. ABA in mammals has both autocrine and paracrine function, and targets cells of the innate immune response, mesenchymal and hemopoietic stem cells and cells involved in the regulation of systemic glucose homeostasis, among others. Moreover, ABA increases glucose uptake in skeletal muscle and adipose tissue through an insulin-independent mechanism. Besides, ABA increases the energy expenditure in the brown and white adipose tissues. In this article, we review the potential of ABA to treat or ameliorate brain and spinal cord disorders, such as sleep disorders, depression, pain and Alzheimer derived memory impairments. Dietary ABA administration shows benefits in humans, as well as extensive data obtained in different mammal models and cell lines. Finally, future perspectives in nutraceutical use of ABA are discussed.
... Carotenoids can capture ROS and, by several reactions, the free electrons are altered to lower energy states, reducing the oxidant effect. 15,16 Therefore, one way to induce the production of lipids and carotenoids is to increase light intensity, but alternative ways also can be explored, namely nitrogen (N) and/or phosphate starvation. 17,18 However, as H 2 O 2 has the potential to produce hydroperoxide radicals and other ROS by light exposure or by reacting with reactive organic compounds, the direct addition of H 2 O 2 to the culture medium deserves investigation. ...
BACKGROUND
Chlorella vulgaris is being explored for several applications such as biodiesel production, nutrient supplementation, animal feed and pharmaceutical products. In this study, the performance of a batch culture under progressive light intensity and the effect of hydrogen peroxide (H2O2) concentration on lipid accumulation were investigated.
RESULTS
Under progressive light intensity (60 to 300 μmol m⁻² s⁻¹), a 43% biomass increase was achieved in comparison with the control light conditions (60 μmol m⁻² s⁻¹), whereas a 300 μmol m⁻² s⁻¹ light intensity caused growth inhibition to the culture. In addition, an increase in carotenoid content from 0.102 mg g⁻¹ biomass (control) to 0.460 mg g⁻¹ (progressive light) and lipid accumulation from 31.0 mg g⁻¹ (control) to 36.5 mg g⁻¹ (progressive light) was observed. However, the moderate illumination conditions (60 μmol m⁻² s⁻¹) induced a very significant increase of chlorophyll b, regarding the progressive light mode, increasing the photosynthetic efficiency. After the growth phase, the biomass was subjected to stress conditions by adding H2O2 to the culture medium at different concentrations: 0.75 mmol L⁻¹ increased the lipid content of the biomass from 3.6% to 10.3% in a 3‐day test, reaching lipid productivity of 70.4 mg L⁻¹ day⁻¹, an increase of ≈40% compared to the phosphate starvatiod for the same culture time.
CONCLUSION
The progressive light system allowed an increase in biomass and lipid accumulation. Together with the exposure to H2O2, this work provides a new approach for lipid and pigment production from microalgae. © 2022 The Authors. Journal of Chemical Technology and Biotechnology published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry (SCI).
... The carotenoids have a many biological functions, and they are responsible for coloring certain types of plants and animals (Vershinin, 1999). The carotenoids have the important function of cells, protecting the air and light (Britton and Hornero-Méndez, 1997). ...
The reactive oxygen species (ROS) have a significant task in many physiological function such as capacitation, hyperactivity and sperm penetration. ROS causes many conditions in the male reproductive system such as prostate cancer, varicoceles, cryptorchidism infections, obstructive lesions, cystic fibrosis, and trauma. ROS usually has high reactive action because the outer shell electron. The carotenoids may affect the properties of cell membranes (permeability, thickness, mechanical strength, rigidity), and decrease ROS effect. It is can be organized in plants, bacteria, fungi, algae and in many animals by combining it with food. The structure of the carotenoids consists of eight units of isoprene, leading to the C40 backbone. The carotenoids are essential component of many types of a plant. The carotenoids can remove free radicals from the biological system by inhibiting or interacting with oxidation reactions make safety products. Rams' sperm are very sensitive to environmental changes and prone to crashing when exposed to higher levels of ROS than any other animal. So, we present a broad overview of the functional properties of carotenoids and significant effects on the ram sperm quality.
... Astaxanthin ((3S-3'S)-dihydroxy-β,β,-carotene-4,4'-dione) is a xanthophyll carotenoid naturally synthesized by some plants, algae, fungi, and bacteria (Boussiba and Vonshak 1991;Johnson and An 1991). It shows a strong antioxidant activity to scavenge reactive oxygen species (ROS) due to unique con guration of thirteen conjugated double bonds in its chemical formula (Vershinin 1999). Because of higher antioxidant activity compared to other antioxidant such as vitamin E, ß-carotene and vitamin-C, astaxanthin have received considerable attention in application of cosmetic, food, pharmaceutical, nutraceutical and aquaculture industries (Hussein et al. 2006;Guerin et al. 2003;Lorenz and Cysewski 2000). ...
Astaxanthin is a natural carotenoid with strong antioxidant capacity. The high demand on astaxanthin by cosmetic, food, pharmaceutical and nutraceutical industries promote its value in the biotechnological research. Several organisms have been characterized as direct or indirect source for astaxanthin. Haematococcus pluvialis has been characterized as one of the most promising species for astaxanthin biosynthesis. Even though H. pluvialis as an advantage in producing astaxanthin, its slow grow-yield limits usage of the species for large-scale production. In this study we generated mutated H. pluvialis strain by using one-step random UV mutagenesis approach for higher biomass production in the green flagellated period and in turn higher astaxanthin accumulation in red stage. Isolated mutant strains were tested for the astaxanthin accumulation and yield of biomass. Among tested strains only mutant strain designated as only MT-3-7-2 showed a consistent and higher growth pattern, the rest had shown a fluctuated and then decreased growth rate than wild type. To demonstrate the phenotypical changes in MT-3-7-2 is associated with transcriptome, we carried out comparative analysis of transcriptome profiles between MT-3-7-2 and the wild type strains. De novo assembly was carried out to obtain the transcripts. Differential expression levels for the transcripts were evaluated by functional annotation analysis. Data showed that increased biomass for the MT-3-7-2 strain was different from wild type with expression of transcripts upregulated in carbohydrate metabolism and downregulated in lipid metabolisms. Our data suggests a switching mechanism is enrolled between carbohydrate and lipid metabolism to regulate cell proliferation and stress responses.
... Carotenoid structure depicts a polyene chain consisting of 9-11 double bonds and possibly terminating in rings. This structure of conjugated double bonds leads to a high reducing potential, or the ability to transfer electrons throughout the molecule [33]. Terpenoids are modified class of naturally occurring organic chemicals derived from the 5-carbon compound isoprene called terpenes with different functional groups and oxidized methyl group moved or removed at various positions [34]. ...
Cancer is one of the leading causes of mortality worldwide. Currently available anticancer therapeutic strategies are not able to improve the survival rate of patients over the past few decades. Research suggests that cancer cells develop multidrug resistance (MDR) against chemotherapeutics that lead to enhanced proliferation, epithelial to mesenchymal transition (EMT), invasion and metastasis. Hence, there is an urgent need for an alternative strategy to treat this disease. Recently, phytochemicals have gained immense attention as a promising anticancer agent by targeting multimodal oncogenic pathways, inducing cell cycle arrest and apoptosis in preclinical studies. However, their clinical application is limited due to poor aqueous solubility, poor bioavailability, low cellular uptake and narrow therapeutic index. Therefore, to address these challenges, phytochemical-based nanomedicine i.e. phytonanomedicine have been developed that can improve pharmacokinetics profile in in vivo systems. In this review, we aim to summarize challenges in cancer treatment and the status of phytonanomedicine for effective cancer treatment in preclinical and clinical studies.
... Carotenoids may have first emerged in archaea as molecules that reinforced biological membranes as "molecular rivets" with just the right length and structure to span the phospholipid bilayer [18,64]. In many other organisms, carotenoids are also localized in membranes. ...
A synthesis is provided of the roles of the carotenoids zeaxanthin and/or lutein in opposing (i) photodamage in plants, (ii) photodamage to the human eye as well as cognitive dysfunction and a host of human diseases and disorders, and (iii) damage to extremophile microorganisms in the most inhospitable environments on earth. Selected examples are used to examine microenvironments and basic biological structures with which these xanthophylls associate as well as the effect of the organisms’ external environment. An overview is presented of the multiple principal mechanisms through which these xanthophylls can directly or indirectly impact organisms’ internal redox (oxidant/antioxidant) balance that provides input into the orchestration of growth, development, and defense in prokaryotic microorganisms, plants, and humans. Gaps in the research are identified, specifically with respect to the need for further in vivo assessment of the mechanisms.
... Carotenoids are tetraterpenoids sharing a carbon chain structure with 9-11 conjugated double bonds. The ability of these pigments to absorb light of specific wavelengths is related to the length of the carotenoid chain, which in turn affects colouration in the range from yellow to red [20,21]. Unlike anthocyanins, carotenoids are synthesised in bacteria, algae, and plants [22]. ...
Given the general beneficial effects of antioxidants-rich foods on human health and disease prevention, there is a continuous interest in plant secondary metabolites conferring attractive colors to fruits and grains and responsible, together with others, for nutraceutical properties. Cereals and Solanaceae are important components of the human diet, thus, they are the main targets for functional food development by exploitation of genetic resources and metabolic engineering. In this review,
we focus on the impact of antioxidants-rich cereal and Solanaceae derived foods on human health by analyzing natural biodiversity and biotechnological strategies aiming at increasing the antioxidant level of grains and fruits, the impact of agronomic practices and food processing on antioxidant properties combined with a focus on the current state of pre-clinical and clinical studies. Despite the strong evidence in in vitro and animal studies supporting the beneficial effects of antioxidants-rich diets in preventing diseases, clinical studies are still not sufficient to prove the impact of antioxidant rich cereal and Solanaceae derived foods on human.
... Most of the CTs are lipophilic in nature and they have the capacity to penetrate BBB [155]. CTs are regarded as molecular rivets, as the length of this form of the molecule is nearly the same as the phospholipid bilayer, which provides rigidity and stability to the phospholipid membrane [156,157]. ...
Neurodegenerative disorders (NDs) including Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis , Huntington's disease, and multiple sclerosis have various disease-specific causal factors and pathological features. A very common characteristic of NDs is oxidative stress (OS), which takes place due to the elevated generation of reactive oxygen species during the progression of NDs. Furthermore, the pathological condition of NDs including an increased level of protein aggregates can further lead to chronic inflammation because of the mi-.pk (M. Shah), agnieszka.najda@up.lublin.pl (A. Najda), abdeldaim.m@vet.suez.edu.eg (M.M. Abdel-Daim). Anti-inflammatory croglial activation. Carotenoids (CTs) are naturally occurring pigments that play a significant role in averting brain disorders. More than 750 CTs are present in nature, and they are widely available in plants, microorganisms , and animals. CTs are accountable for the red, yellow, and orange pigments in several animals and plants, and these colors usually indicate various types of CTs. CTs exert various bioactive properties because of its characteristic structure, including anti-inflammatory and antioxidant properties. Due to the protective properties of CTs, levels of CTs in the human body have been markedly linked with the prevention and treatment of multiple diseases including NDs. In this review, we have summarized the relationship between OS, neuroinflammation, and NDs. In addition, we have also particularly focused on the antioxidants and anti-neuroinflammatory properties of CTs in the management of NDs.
... Evcil hayvanlar tarafından sentezlenemeyen karotenlerin hayvan yemlerine ilave edilerek verilmesi gerekmektedir. Hayvan bünyesinde yumurtaya ve etlik piliçlerde deriye renk vermesinin yansıra; diğer biyolojik özellikleri, hayvanlarda retinoik asidin sentezlenmesinde görev alarak görme pigmenti olarak rol almaktadırlar (Vershinin, 1999). Karotenlerin bağışıklık sistemini güçlendirme, antioksidan aktivite gösterme, katarakt gibi yaşlanmaya bağlı dejenaratif hastalıkları azaltma, antiobesite/hipolipidik özellikleri ile endokrin sisteminde görev aldıkları da ileri sürülmektedir (Kushwaha ve ark., 2014). ...
In this study, egg samples and feed samples were taken from 32-week-old Novagen, 44-week-old Tinted, 45 and 58-week-old Lohman laying hens reared in commercial egg farms in Muş and Van provinces for three months with 1-month intervals. Total carotene, lutein, zeaxanthin canthaxanthin, apoester and beta-carotene as an individual carotene, vitamin A (retinol) and vitamin E content of egg yolk and feed samples were determined by HPLC. In this study, the roche scale and Minolta L*, a * and b * values of egg yolk were determined on the base of breed and periods. Egg yolk roche pigment scale results showed that except Tinted breed chickens in the second period, in general Lohman breed chickens were significantly higher in the 1st, 2nd, 3rd periods than Novagen and Tinted breeds egg yolk. Minolta a * values showed that generally egg yolks of Lohman chickens were darker red than Novagen egg yolks. While, minolta b* values were not statistically different among breeders in the second period, it has been observed that Novagen and Tinted breed hens egg yolks were significantly yellower than Lohman hen egg yolk in the first period, but the opposite was observed in the third period. While egg yolk total carotene contents were found to be lowest in Tinted breed eggs in the first period, no difference was found in the second period and the lowest total carotene content was found in Novagen breed chicken eggs in the third period. The results of this study concluded that the pigment and vitamin content of each egg in the market may vary as a reflection of consumed feeds.
... Микроводоросли -один из самых эффективных источников возобновляемой энергии. В них содержится до 50-70% белка, 30% липидов, более 40% глицерина, до 14% каротина и довольно высокая концентрация витаминов B1, B2, B3, B6, B12, E, K, D и т. д. в сравнении с другими растениями или животными [1,2]. В то же время водоросли способны усваивать атмосферный углекислый газ, что косвенно может привести к ослаблению проблемы глобального потепления. ...
: The role of phototrophs is examined in alternative energy, with the main emphasis on unicellular algae. Particular attention is paid to the use of phototrophs for generating electricity using biofuel cells (plant and enzymatic biofuel cells are discussed). This study focuses on microbial fuel cells (MFC), which, along with electric power, allow obtaining biofuels and biohydrogen. This article explains the factors limiting the MFC power, and ways of overcoming them. For example, it seems promising to develop various photobioreactors in order to reduce the loss of MFC power due to overvoltage. The use of microphototrophs in MFC has led to the development of photosynthetic MFC (or PhotoMFC) through the design of autotrophic photobioreactors with forced illumination. They allow generating oxygen through photosynthesis, both in situ and ex situ, by recirculating oxygen from the photobioreactor to the cathode chamber. Artificial redox mediators can be used here, transferring electrons directly from the non-catalytic cathode to O2, formed as a result of the photosynthetic activity of algae. Biologically catalyzed cathodes have been proven to generate less power than chemical catalysts. It is noted, that the MFC installations with the micro-algae allow utilizing a wider circle of different connections – the components of effluents and withdrawals: organic acids, sugar, alcohols, fats and other substrata. The use of phototrophs for the production of biofuels is of special interest. Several different types of renewable biofuels can be produced from microalgae, the production of which can be combined with wastewater treatment, CO2 capture and production of various compounds.
... These data suggest that there are combinations in the skin that provide selective filtering of frequencies in the optical range. It is possible that this selectivity is provided by numerous carotenoids, which have been shown to perform a number of independent biological functions, including spectral filtering [11,43]. Retinylidenes of photoreceptor cells, which are found not only in the retina of the eye, but also in various tissues, including the skin of animals and humans, can also carry out partial filtering of light waves. ...
... The large concentration of carotenoids in the belowground organ of P. campestris may be related to the defense against herbivory and oxidative stress (Vershinin, 1999;Vasconcelos et al., 2020). Carotenoid storage in both aerial and belowground organs was observed by Mercadante-Simões et al. (2014) for Tontelea micrantha (Mart. ...
Resprouting from belowground buds enables plants to survive after aboveground biomass loss in the Brazilian Cerrado. Although resprouting is a common functional strategy in disturbance-prone ecosystems, we poorly understand the anatomy of belowground bud-bearing organs. Here, we aimed to describe traits related to the resprouting ability of four native Cerrado species from an area under regeneration after the removal of a slash-pine plantation (Pinus elliottii), by analyzing their belowground bud-bank, the structural features of their belowground bud-bearing organs, and their storage compounds. We evaluated the belowground bud bank size of all species, conducted anatomical analyses to describe their belowground bud-bearing organs, identified the chemical compounds stored. The belowground bud bank size varied according to the number of belowground bases of aerial stems and branches emitted by the belowground bud-bearing organs. Anemopaegma arvense, Peltaea polymorpha, and Psidium laruotteanum presented xylopodia. The xylopodium of A. arvense had plagiotropic roots with adventitious buds. Moreover, A. arvense and Peritassa campestris presented cambial variants in their belowground organs (phloem wedges and successive cambia, respectively). Starch, phenolic compounds, and carotenoids were the main storage and protective compounds, occurring in the periderm, vascular rays, and parenchyma pith cells. Our findings suggest that the analyzed species were able to resprout after pine removal due to the maintenance of a belowground bud bank protected and resourced by belowground bud-bearing organs. Gaining such insight on belowground bud banks is essential in the understanding of the resprouting ability after natural and/or human-induced disturbances. Full text also available in: https://authors.elsevier.com/a/1dBCw1JWF1t0JM
... Carotenoids are thought to have evolved to stabilize lipid membranes (Vershinin 1999). The eventual association of carotenoids with proteins greatly expanded their range of properties and functions. ...
Carotenoids are ancient pigment molecules that, when associated with proteins, have a tremendous range of functional properties. Unlike most protein prosthetic groups, there are no recognizable primary structure motifs that predict carotenoid binding, hence the structural details of their amino acid interactions in proteins must be worked out empirically. Here we describe our recent efforts to combine complementary biophysical methods to elucidate the precise details of protein-carotenoid interactions in the Orange Carotenoid Protein and its evolutionary antecedents, the Helical Carotenoid Proteins (HCPs), CTD-like carotenoid proteins (CCPs).
Phytoplanktons include cyanobacteria, dinoflagellates, and diatoms, which form the foundation of marine and freshwater food webs while effectively maintaining the oxygen and carbon levels globally. They also contribute to 50–80% of the total oxygen produced on Earth. Phytoplanktons produce structurally and functionally diverse bioactive metabolites with many applications in medicine and industry. Phytoplankton metabolites (secondary or non-primary metabolites) such as fatty acids, phycobiliproteins, fucoidans, fucoxanthin, laminarin, mannitol, alginic acids, carotenoids, vitamins, and mineral salts are shown to prevent various human diseases through their application as antidiabetic, antioxidant, antibacterial, anti-inflammatory, anticancer, antifungal, antimalarial, antiviral, and prevention of other metabolic diseases. Some of the metabolites offer an extended role in defense (allelopathic, antipredator, and antibacterial compounds) and/or cell-to-cell communication (e.g., polyunsaturated aldehydes (PUAs)). Until recently, marine microbes were almost ignored and remained unexplored as a potential depot of unique biologically active metabolites. Hence, researchers have now highlighted the prominence of marine microorganisms in producing unusual bioactive metabolites that are otherwise absent in terrestrial species. The presence of these unusual metabolites encourages the application of marine phytoplankton to produce industrially vital compounds. Like phytoplankton, seaweeds or macroalgae are also known for their bioactive metabolites and phytochemicals, demonstrating promising applications in nutraceuticals, pharmaceuticals, and edible seaweeds. This chapter gives a detailed discussion on synthesizing the bioactive metabolites in marine phytoplankton and macroalgae, their pharmacological activity, and their potential application in medicine.
Lycopene β-cyclase (EC 5.5.1.19) is one of the key enzymes in the biosynthesis of β-carotene and derived carotenoids. It catalyzes isomerase reactions to form β-carotene from lycopene by β-cyclization of both of its ψ-ends. Lycopene β-cyclases are widespread in nature. We systematically analyzed the phylogeny of lycopene β-cyclases from all kingdoms of life and predicted their transmembrane structures. To this end, a collection of previously characterized lycopene β-cyclase polypeptide sequences served as bait sequences to identify their closest homologues in a range of bacteria, archaea, fungi, algae, and plant species. Furthermore, a DeepTMHMM scan was applied to search for the presence of transmembrane domains. A phylogenetic tree suggests at least five distinct clades, and the DeepTMHMM scan revealed that lycopene β-cyclases are a group of structurally different proteins: membrane-bound and cytosolic enzymes. Representative lycopene β-cyclases were screened in the lycopene-overproducing Corynebacterium glutamicum strain for β-carotene and astaxanthin production. This systematic screening facilitates the identification of new enzymes for carotenoid production. Higher astaxanthin production and less reduction of total carotenoids were achieved with the cytosolic lycopene β-cyclase CrtL from Synechococcus elongatus and the membrane-bound heterodimeric lycopene β-cyclase CrtYcd from Brevibacterium linens.
This preliminary research discusses the extraction of colorants from pumpkin peel as vegetable dyes and the potential dyeing capability of silk and cotton fabrics. For pumpkin extracts, thermal gravity analysis has verified the range of temperature for application, while a combination of UV–vis spectra and high-performance liquid chromatography analysis confirmed the main colored components and structural characteristics. It was found that the extracts of this vegetable dye have excellent thermal stability as well as stability in neutral and acid conditions. With the objective of achieving the greatest absorbency rate of extracted solution, the following optimum extraction conditions were obtained: 100% ethanol, an extraction temperature of 70°C, an extraction time of 60 min, and a material-to-liquor ratio of 1:10. To attain the highest dyeing uptake rate and K/ S values, the optimum dyeing profiles with meta-mordanting for silk fabrics were found to be 95°C, 90 min, pH 5.5, and a liquid ratio of 1:60. The optimum dyeing profiles with meta-mordanting for cotton fabrics were 95°C, 90 min, and a liquid ratio of 1:60. Nearly all colorfastness results for silk and cotton fabrics met the basic requirement of the China National Standard, except a few.
One restriction for biohybrid photovoltaics is the limited conversion of green light by most natural photoactive components. The present study aims to fill the green gap of photosystem I (PSI) with covalently linked fluorophores, ATTO 590 and ATTO 532. Photobiocathodes are prepared by combining a 20 μm thick 3D indium tin oxide (ITO) structure with these constructs to enhance the photocurrent density compared to setups based on native PSI. To this end, two electron transfer mechanisms, with and without a mediator, are studied to evaluate differences in the behavior of the constructs. Wavelength-dependent measurements confirm the influence of the additional fluorophores on the photocurrent. The performance is significantly increased for all modifications compared to native PSI when cytochrome c is present as a redox-mediator. The photocurrent almost doubles from -32.5 to up to -60.9 μA cm-2. For mediator-less photobiocathodes, interestingly, drastic differences appear between the constructs made with various dyes. While the turnover frequency (TOF) is doubled to 10 e-/PSI/s for PSI-ATTO590 on the 3D ITO compared to the reference specimen, the photocurrents are slightly smaller since the PSI-ATTO590 coverage is low. In contrast, the PSI-ATTO532 construct performs exceptionally well. The TOF increases to 31 e-/PSI/s, and a photocurrent of -47.0 μA cm-2 is obtained. This current is a factor of 6 better than the reference made with native PSI in direct electron transfer mode and sets a new record for mediator-free photobioelectrodes combining 3D electrode structures and light-converting biocomponents.
Astaxanthin has been widely used as feed supplements in aquaculture, and the effects of which on the growth, immunity, and antioxidant system of aquaculture animals have been demonstrated by phenotype measurement and enzyme activity analysis. However, the molecular response to dietary astaxanthin of aquaculture animals has been rarely described. In this study, the comparative experiment was conducted employing coral grouper (Plectropomus leopardus) juveniles, which were fed with astaxanthin (AX group) or without astaxanthin (control group). The histological and antioxidant enzyme activities analysis of the livers showed dietary astaxanthin could reduce lipid accumulation and oxidative stress. By comparative transcriptome analysis of the livers, a total of 1992 and 981 differentially expressed genes (DEGs) were identified between the AX groups and the control groups at the 40- and 60-day after feeding trial, respectively. Functional analysis of DEGs showed that multiple enriched terms were related to oxidative stress, immune response, fat metabolism, cholesterol metabolism, and steroid biosynthesis. Furthermore, the functions of specific DEGs in oxidative stress and immune response were validated in primary cultured hepatocytes. Finally, weighted gene co-expression network analysis (WGCNA) was performed to construct gene co-expression networks, and identified key factors which may play vital roles in regulating the molecular response to astaxanthin feeding in livers of P. leopardus. Taken together, our findings facilitate the understanding of the molecular basis underlying the protective effect of dietary astaxanthin in P. leopardus, which provides valuable insights into the nutritional strategies of the aquaculture industry.
Linear polyenes are an important class of compounds containing two or more alternating carbon‐carbon double and single bonds that are soluble primarily in organic non‐polar solvents. However, determining the relative basicity of unsubstituted polyenes experimentally has proven to be challenging in practice because such studies require mixing non‐polar polyene‐organic solvent mixtures with high concentrations of moderately polar organic acids. In this study, we used both computational and experimental approaches to calculate potential sites of protonation of trans‐1,4‐diphenyl‐1,3‐butadiene (DPB), all trans‐1,6‐diphenyl‐1,3,5‐hexatriene (DPH), and all trans‐1,8‐diphenyl‐1,3,5,7‐octatetraene (DPO) with trifluoroacetic acid (TFAH) in both n‐hexane or benzene solvents. Density functional theory (DFT) calculations with a 6‐311+G (d,p) basis set and the B3LYP exchange correlation functional predict that the carbon atoms α to either phenyl ring are the most likely sites of protonation. Our calculations indicate that the basicities of the DPPs increase with increasing length of the polyene moiety (DPO > DPH >> DPB) in the gas phase and in both benzene and n–heptane solvents. Consistent with these computational predictions, the experimental rates of protonation of DPB, DPH, and DPO in benzene and hexane were consistent with the calculated basicity trends. Dynamic light scattering data confirmed that these reactions were phase separated resulting in emulsions between TFAH and both solvents; these phase separations complicated specification of the actual reaction rates. Finally, GC‐MS and NMR data confirm that the crude products from the protonation of DPB and DPH were mixtures of DPB and DPH dimers. In significant contrast, DPO did not form dimers but rather an unidentified monomeric trifluoroacetate addition product.
Microalgae, the photosynthetic autotrophs, are considered an important base of the food web. Furthermore, microalgae also have the potential to be a great candidate for sustainable sources of energy, soil conditioner, bioactive compounds and other economically important products as well as an alternative mode of agriculture. It is a well-known fact that the survival, growth and productivity of any organism including microalgae are strongly affected not only by their physiological and biochemical processes but also by biotic and abiotic factors in the environment. In the present scenario when global climate change which is one of the most important issues worldwide may also have a great impact on microalgal growth. Although there are many more but increased temperature and elevated light intensity (including ultraviolet radiations) are the two main repercussions of global climate change. Given that growth is balanced under a specific set of environmental conditions, therefore many microalgae can adapt to these two major stresses or extreme conditions. Interestingly by virtue of nature, we humans are blessed by such adaptation of microalgae which presents a source of a sustainable source of energy, valuable products and alternative modes of agriculture. In the present scenario where we are facing extreme climate changes, global warming and ozone depletion, understanding this adaptive behaviour of microalgae will be very useful so that we are future-ready to face such extreme stress conditions.KeywordsAdaptationBiofuelLight-stressMicroalgaePsycrophilesTemperature-stressXanthophyll cycle
The thermophilic bacterium Rhodothermus marinus has mainly been studied for its thermostable enzymes. More recently, the potential of using the species as a cell factory and in biorefinery platforms has been explored, due to the elevated growth temperature, native production of compounds such as carotenoids and EPSs, the ability to grow on a wide range of carbon sources including polysaccharides, and available genetic tools. A comprehensive understanding of the metabolism of production organisms is crucial. Here, we report a genome-scale metabolic model of R. marinus DSM 4252 T . Moreover, the genome of the genetically amenable R. marinus ISCaR-493 was sequenced and the analysis of the core genome indicated that the model could be used for both strains. Bioreactor growth data was obtained, used for constraining the model and the predicted and experimental growth rates were compared. The model correctly predicted the growth rates of both strains. During the reconstruction process, different aspects of the R. marinus metabolism were reviewed and subsequently, both cell densities and carotenoid production were investigated for strain ISCaR-493 under different growth conditions. Additionally, the dxs gene, which was not found in the R. marinus genomes, from Thermus thermophilus was cloned on a shuttle vector into strain ISCaR-493 resulting in a higher yield of carotenoids.
Importance
A biorefinery converting biomass into fuels and value-added chemicals is a sustainable alternative to fossil fuel-based chemical synthesis. Rhodothermus marinus is a bacterium that is potentially well suited for biorefineries. It possesses various enzymes that degrade biomass, such as macroalgae and parts of plants (e.g. starch and xylan) and grows at high temperatures (55-77°C) which is beneficial in biorefinery processes. In this study, we reviewed the metabolism of R. marinus and constructed a metabolic model. Such a model can be used to predict phenotypes, e.g. growth under different environmental and genetic conditions. We focused specifically on metabolic features that are of interest in biotechnology, including carotenoid pigments which are used in many different industries. We described cultivations of R. marinus and the resulting carotenoid production in different growth conditions, which aids in understanding how carotenoid yields can be increased in the bacterium.
Phytoene synthase (PSY1), Capsanthin‐capsorubin synthase (CCS), and Pseudo response regulator2‐like (PRR2) are three major genes controlling fruit color in pepper. However, the diversity of fruit color in pepper cannot be completely explained by these three genes. Here, we used an F2 population derived from C. annuum ‘SNU‐mini Orange’ (SO) and C. annuum ‘SNU‐mini Yellow’ (SY), both harboring functional PSY1 and mutated CCS, and observed that yellow color was dominant over orange color. We performed genotyping‐by‐sequencing (GBS) and mapped the genetic locus to a 6.8 Mb region on chromosome 2, which we named CaOr. Among the genes located within the region, we discovered that a splicing mutation in the Zeaxanthin epoxidase (ZEP) leading to premature stop codon of the gene. HPLC analysis showed that SO contained higher amounts of zeaxanthin and total carotenoids in mature fruits than SY. A color complementation assay using E. coli harboring carotenoid biosynthetic genes showed that the mutant ZEP protein had reduced enzymatic activity. Transmission electron microscopy of plastids revealed that the ZEP mutation affected plastid development with more rod‐shaped inner membrane structures in chromoplasts of mature SO fruits. To validate the role of ZEP in fruit color formation, we performed virus‐induced gene silencing (VIGS) of ZEP in the yellow‐fruit cultivar C. annuum 'Micropep Yellow' (MY). The silencing of ZEP caused significant changes in the ratios of zeaxanthin to its downstream products and increased total carotenoid contents. Thus, we conclude that the ZEP genotype can determine orange or yellow mature fruit color in pepper.
Porphyridium cruentum, a cell wall-free marine Rhodophyta microalga was cultured under a 5-day cold stress at 0°C and 15°C, after reaching the late logarithmic growth phase. Compared with the control at 25°C, the cold stress treatment significantly (p < 0.05) increased the microalgal biomass (1.21-fold); the amounts of total polyunsaturated fatty acids (1.22-fold); individual fatty acids including linoleic acid (1.50-fold) and eicosatrienoic acid (1.85-fold), and a major carotenoid zeaxanthin (1.53-fold). Furthermore, production of biodiesel feedstock including total C16 + C18 fatty acids was significantly enhanced (p < 0.05) by 1.18-fold after the cold stress treatment. Principal component analysis further indicated that the biosynthetic pathways of fatty acids and carotenoids in this microalga were correlated with the cold stress treatment. These results suggested that P. cruentum had adjusted its cellular membrane fluidity via an ‘arm-raising and screw-bolt fastening’ mechanism mediated by the synergistic roles of cis-unsaturated fatty acids and carotenoids. The insight obtained from the responses to cold stress in P. cruentum could be a novel technological approach to enhance the production of microalgal metabolites and biodiesel feedstock.
Carotenoids possess strong anti-inflammatory and antioxidant actions in addition to a plethora of other properties. These actions of carotenoids are primarily due to their structure which dictate their functions. Because of their protective potential in disease states, carotenoids are associated with prevention and/or treatment of various neurological diseases. In this chapter, the role(s) of carotenoids in various neurological diseases such as Alzheimer’s disease, vascular dementia, Lewy body dementia, mild cognitive impairment, neurological trauma, brain tumor, schizophrenia, depression, Parkinson’s disease and multiple sclerosis, have been reviewed. A number of studies report associations of low levels of carotenoids with higher likelihood of neurological diseases. Other investigations describe beneficial and protective effects of pharmacological or dietary interventions which lead to enhancement of carotenoids levels in the body. However, further validation of these beneficial actions is required both in clinical and animal studies. Development of good animal models of neurological diseases will help.
Carotenoids (also known as lipochromes) are multipurpose, mesmeric, multidimensional, multifaceted and challenging natural pigments. As secondary plant metabolites, they are remarkable for their wide dissemination, structural variety, and numerous actions. They perform essential and specialized i.e. both and primary secondary roles in plants. They are colorful and abundantly present class of isoprenoids which are synthesized photosynthetically (plants) and non-photosynthetically (fungi & bacteria). Innately, despite from few species of aphids, carotenoids are not been synthesized in animals, therefore, animals require them through daily diet. They exist in plant tissues as esterified (with fatty acids), forming complex (with proteins and sugars) or free forms (crystalline or amorphous). The conjugate double-bond (c.d.b.) system of carotenoid structure regulates biological functions, e.g. energy transfer, light absorption during photosynthesis, and defense from damaging properties of light in the photosynthesis. They share a common a skeleton formed by 2 isoprenoid units linked in such a way that the molecule is linear and has inverted symmetry in the center and several c.d.b. in the chain. All carotenoids retain their core structural and functional feature of carotenoids, i.e. polyene chain. Regardless of the presence of oxygen-containing groups, almost all carotenoids are hydrophobic. The carotenoids are responsible for biological activities, including photoprotection, photosynthesis, plant colors, and cell signaling. Health aspect of several carotenoids is undisputed.
Pigmentation is an essential characteristic of microbe, plant and animals responsible for coloration, development and standard growth. Coloration is one of the vital qualities that increase the consumer acceptability of products. Coloration can be produced employing synthetic or by natural pigments. Gradually the demand for natural colorants has been increasing amongst the public due to growing awareness of toxicity and environmental concerns. Carotenoids are the most abundant pigments found in nature owing to special attention on its biotechnological production from microbes for industrial purpose. While the microbes and plants can synthesize carotenoids de novo, animals need to have precursor items on their diet to produce it. The large scale industrial production of carotenoids is expected to touch $2.0 billion by 2022.
Synthese des mecanismes de photoprotection chez les vegetaux, en reponse a un eclairement energetique; implication des carotenoides, en particulier la zeaxanthine, a la dissipation d'energie, en relation avec le cycle des xanthophylles
Acholeplasma laidlawii cells grown with oleic acid produced much more colored carotenoids than did cells grown with elaidic acid. The amount of carotenoids was decreased 80 to 90% by growing the cells with 0.05 M propionate, resulting in a marked increase in the mobility of both 5-doxylstearate and 12-doxylstearate incorporated into the membranes. The fatty acid composition of the propionate-grown cells differed from that of cells grown without propionate by containing odd-numbered rather than even-numbered saturated fatty acids, but the ratios of saturated to unsaturated fatty acids were the same. To determine whether the carotenoids are the cause for the restricted mobility in the membranes, the carotenoids were selectively removed from A. laidlawii membranes by incubating the membranes with phosphatidylcholine vesicles. The carotenoid-depleted membranes showed an increase in the mobility of the hydrocarbon chains of the spin-labeled fatty acids. Furthermore, the incorporation of carotenoids into artificial membrane vesicles restricted the mobility of the hydrocarbon chain. Our results support the notion that the carotenoids in A. laidlawii act as a rigid insert reinforcing the membrane bilayer.
The carotenoids are not only amongst the most widespread of the naturally occurring groups of pigments, but probably also have the most varied functions; witness their known roles in photokinetic responses of plants, in phototropic responses of fish and as vitamin A precursors in mammals and birds. Pigments with such wide distribution and such diverse functions are obviously of great interest to biological scientists with very different specializa tions, especially as it is unlikely that the study of the functions of carotenoids is anywhere near complete. The primary aim of the present work is to discuss the distribution, bio genesis and function of the carotenoids throughout the plant and animal kingdoms in such a way that, because of, rather than in spite of its bio chemical bias, it will be of value to workers interested in all the biological aspects of these pigments. The biochemical approach is considered the most effective because, generally speaking, most progress in the study of carotenoids in living material has been achieved using biochemical techniques, be they applied by zoologists, botanists, entomologists, microbiologists or other specialists; what is even more important is that a consideration of the present position makes it certain that further fundamental progress will also be made along biochemical lines.
Carotenoids are shown to inhnbit the initiation phase of carcinogenesis due to their antioxidant activity. But neither antioxidant nor pro-vitamine properties of these pigments can explain their antitumor action in many cases. Studying this problem another property of carotenoids must be accounted: their ability to modify biomembranes reinforcing lipid bilayer and decreasing its fluidity. High level of membrane fluidity is characteristic of the tumor cells and they are very sensitive to its decrease. Supressing of membrane fluidity is the mechanism for anticancer action of tamoxifen-related compounds, and there are strong reasons to suggest the same mechanism for carotenoids.
Light-dependent transformations of carotenoids in 11 species of marine macroalgae have been studied in laboratory conditions. Beta-carotene and zeaxanthin were found in Gracilaria verrucosa, G. lichenoides, Ahnfeltia tobuchiensis, and beta-carotene and lutein in Phyllophora nervosa (Rhodophyta). Laminaria cichorioides, Coccophora langsdorfii, Cystoseira crassipes and Sargassum pallidum (Phaeophyceae, Chromophyta) possess beta- carotene, fucoxanthin and violaxanthin. Carotenoids typical for higher plants are present in Ulva fenestrata (Chlorophyta), alpha-carotene, neoxanthin, violaxanthin, siphonaxanthin and its 2 esters identified as siphonein A and siphonein B were found in Codium fragile and Cladophora opaca. The violaxanthin cycle was shown in Ulva fenestrata. No light-dependent transformations of carotenoids were observed in red and brown algae. A new phenomenon of the reversible light-induced de-esterification of siphonein B, in which siphonaxanthin is accumulated in high light and siphonein B in low light, was found in Codium fragile and Cladophora opaca. These data taken in the context of algal ecology are consistent with the understanding of the xanthophyll cycle as a protection for photosynthetic structures under stress conditions such as high light.
1.1. In embryos of all stages of development to early pluteus only one carotenoid, all-trans β-echinenon, was detected.2.2. The data of Raman and absorption spectroscopy indicate that echinenon in embryo is probably dissolved in lipid formations and not bound to protein.3.3. During development, the decrease of echinenon content to 50% of the initial level was observed. The antioxidant role of echinenon in embryo is proposed.
Carotenoids are essential for the survival of photosynthetic organisms. Carotenoids have been shown to have two major functions in photosynthesis. They act as photoprotective agents, preventing the harmful photodynamic reaction, and as accessory light-harvesting pigments, extending the spectral range over which light drives photosynthesis. The first of these two functions depends on the triplet states of the carotenoid, while the second depends on their excited singlet states. The chapter discusses the way carotenoids are organized and arranged within the photosynthetic apparatus. Most common carotenoids found in photosynthetic cells and organelles are rather hydrophobic molecules and are typically located within the photosynthetic membranes. However, they are not usually freely mobile within the lipid interior of these membranes but rather are noncovalently bound to the photosynthetic reaction centers and the light-harvesting complexes. Although carotenoids function just as well in plants and algae as in photosynthetic bacteria, the antenna system of the purple bacteria is an ideal model system in which to demonstrate their functions, because they are spectrally so well defined and have a much simpler organization than those of plants.
Hyphae of light‐grown V. agaricinum (Link) Corda contain many lipid bodies. The hypae were disrupted and the membranes immediately pelleted by a 48 000 g spin for 30 min. The major part (90%) of the carotenoids was found in a lipid layer on top of the supernatant. Carotenoids extracted from the lipid layer in diethyl ether had an absorption maximum at 488 nm. On the basis of spectra in different organic solvents the main component was tentatively. Thin layer chromatography of extracted and saponified carotenoids revealed the presence of one major and one minor component.
The 48 000 g pellet contained 80% of the NAD ⁺ ‐dependent malate dehydrogenase (marker for mitrochondria), 25% of the antimycin‐resistant NADH‐cytochrome c reductase (marker for mitochodria and endoplasmic reticulum) and 10% of the proteins and the carotenoids. The latter were different from the carotenoids in the lipid layer in that the absorption maximum was at 471 nm in diethyl ether.
Further fractionation of the 48 000 g pellet showed the presence of carotenoids in both mitochondria and endoplasmic reticulum (ER) all with an absorption maximum at 471 nm. On a thin layer plate these carotenoids migrated in one band coinciding with the minor band of the lipid layer. On a continous Percoll gradient two main areas of mitochodrial activity (1.068 and 1.063 g ml ⁻¹ ) were clearly separated from the ER (1.059 g ml ⁻¹ ). The carotenoid content was about 0.6 and 0.7–1.0 μg (mg protein) ⁻¹ for mitochondria and ER, respectively, equivalent to 1–2 carotenoid molecules per 1000 lipid molecules. The possible role of these membrane‐bound carotenoid molecules is discussed.
The interactions of tamoxifen with lipid bilayers of model and native membranes were investigated by fluorescence polarization of 1,6-diphenyl-1,3,5-hexatriene (DPH) and by intramolecular excimer formation of 1,3-di(1-pyrenyl)propane (Py(3)Py). The effects of TAM on liposomes of DMPC, DPPC and DSPC are temperature dependent. In the fluid phase, TAM reduces dynamics of the upper bilayer region as observed by Py(3)Py and has no effect on the hydrophobic region as detected by DPH. In the gel phase, the effects of TAM evaluated by Py(3)Py are not discernible for DMPC and DPPC bilayers, whereas DSPC bilayers become more fluid. However, DPH detects a strong fluidizing effect of TAM in the hydrophobic region of the above membrane systems, where DPH distributes, as compared with the small effects detected by Py(3)Py. TAM decreases the main phase transition temperature but does not extensively broaden the transition thermotropic profile of pure lipids, except for bilayers of DMPC where TAM induces a significant broadening detected with the two probes. In fluid liposomes of sarcoplasmic reticulum lipids and native membranes, TAM induces an ordering effect, as evidenced by Py(3)Py, failing DPH to detect any apparent effect as observed for the fluid phase of liposomes of pure lipid bilayers. These findings confirm the hydrophobic nature of tamoxifen and suggest that the localization and effects of TAM are modulated by the order and fluidity of the bilayer. These changes in the dynamic properties of lipids and the non-specific interactions with membrane lipids, depending on the order or fluidity of the biomembrane, may be important for the multiple cellular effects and action mechanisms of tamoxifen.
Carotenoids in eight species of freshwater and sea mollusks were investigated. In the nonreproductive organs of all species, only all-trans C40-xanthophylls were found. Carotenes are limited to hepatopancreas. No carotenoid derivatives or carotenoids with < 10 conjugated double bonds were detected. Carotenoids in molluskan cells are present in all subcellular fractions; the major part of them is located in plasma membrane. There are no special carotenoid-containing pigmented granules (“cytosomes” “carotenoxysomes”) in molluskan cells. Comparison of both Raman and absorption spectra of carotenoids in situ with those in CHCI3 suggests that pigments are dissolved in lipid matrix of membranes and not bound to proteins. No changes of carotenoid content or carotenoid pattern in Dreissena polymorpha, Unio pictorum and Viviparus contectus were observed during 10 days of starvation. There were no changes in isolated gills within 2 days as well. In the freshwater species with the exception of D. polymorpha, carotenoid content changes after the fast water temperature changes: with elevation of temperature, the carotenoid content in organs increases and vice versa, without any change in carotenoid composition. This phenomenon is shown to be due to rearrangement of pigments between the hepatopancreas and other organs. The results suggest that the role of carotenoids in molluskan tissues is not connected with their chemical transformations. The most probable function of carotenoids in mollusks is the stabilisation of cell membranes' fluidity.
Upon strong illumination (30 min, 1400 W m−2) of intact pea leaves the spin label-monitored fluidity of the isolated thylakoid membranes decreases in the peripheral region of the hydrophobic core (as measured with the 5-doxylstearic acid spin label) but remains unchanged in the membrane interior (as measured with the 16-doxylstearic acid spin label). At the same time, as a consequence of the light driven de-epoxidation of violaxanthin to zeaxanthin, the molar ratio of these two pigments in the photosynthetic apparatus deceases from 6.25 to 0.64. The light-induced alterations of thylakoid fluidity have been attributed to the membrane-modifying effect of zeaxanthin. Such concept is supported by the results of analogous experiments in which the xanthophyll cycle-related zeaxanthin accumulation was partially blocked by the de-epoxidase inhibitor, dithiothreitol.
Derivatives of one triterpene family, the hopane family, are widely distributed in prokaryotes; they may be localized in membranes, playing there the same role as sterols play in eukaryotes, as a result of their similar size, rigidity, and amphiphilic character. Their biosynthesis embodies many primitive features compared to that of sterols and could have evolved toward the latter once aerobic conditions had been established. Membrane reinforcement appears to be achieved in other prokaryotes by other mechanisms, involving either approximately 40-A-long rigid hydrocarbon chains terminated by one polar group acting like a peg through the double-layer or similar chains terminated by two polar groups acting like tie-bars across the membrane. These inserts can be tetraterpenes (e.g., carotenoids). The biophysical function of membrane optimizers appears to have evolved toward sterols by changes limited to only a few enzymatic steps of the same fundamental biosynthetic processes.
Carotenoid pigments, including hydrocarbons such as beta-carotene or xanthophylls such as lutein and zeaxanthin, are very widely distributed in nature, where they play an important role in protecting cells and organisms against the harmful effects of light, air, and sensitizer pigments. This process has been demonstrated in bacteria, algae, plants, animals, and even in humans in the light-sensitive disease, erythropoietic protoporphyria. The primary mechanism of action of this phenomenon appears to be the ability of carotenoids to quench excited sensitizer molecules as well as quench 1O2. In addition to this protection, and potentially of even greater biological importance, is the fact that carotenoids can also serve as antioxidants under conditions other than photosensitization. This review presents the data available indicating the extent of this important function. Antioxidant action can be documented in both enzymic and nonenzymic systems, and has been reported in subcellular, cellular, and animal studies. In fact, the many reports indicating that carotenoids may possess some anticarcinogenic properties may well be related to their ability to interact with and quench various radical species that can be generated within cells.
Acholeplasma laidlawii (oral strain) cells were grown in a lipid-extracted medium supplemented with arachidic acid (C20:0). The carotenoid content of the plasma membrane was appreciably dependent upon the levels of acetate or propionate present in the growth medium. 1.1. Membranes isolated from cells grown in propionate (5 g/l) contained a low level of carotenoids, approximately 11 wt% of the total lipids. Neither the fatty acyl composition nor the membrane lipid/protein ratio was altered. However, spin-labelling experiments demonstrated a greater lipid fluidity in those membranes, as compared to those from cells grown in an acetate containing growth medium. Membranes isolated from cells grown in acetate (5 g/l) were characterized by a higher buoyant density, higher osmotic fragility and lower glycerol permeability.2.2. Growing cells in a medium containing 20 g/l of propionate instead of acetate, the membrane carotenoid content decreased by 57-fold. For cells grown in an acetate medium (20 g/l), high levels of carotenoid pigments (about 38 wt% of the total lipids) were obtained; fewer arachidoyl and more unsaturated acyl groups were found in the membrane lipids. Spin-labelling experiments showed only a very slight difference in lipid fluidity between the two types of membrane.3.3. These results suggest that carotenoid pigments rigidify the Acholeplasma membrane and the organism maintains its membrane fluidity within a narrow range by modifying the fatty acyl composition of the membrane lipids.
Within the past few years, much has been learned about the metabolism and actions of vitamin A and the carotenoids. This article reviews the biochemical and cellular events in retinoid metabolism that lead to production of retinoic acid, an active metabolite of vitamin A. Retinoic acid functions in a hormone-like manner to regulate the expression of a number of genes. Beta carotene is now under study as an anticancer agent and for its possible beneficial effects in a number of chronic diseases. Current recommendations for carotene intake exceed the usual daily intake nearly fourfold.
The eggs of Pomacea canaliculata australis (d'Orbigny), an amphibious freshwater prosobranch snail, have, as the most important nitrogenous constituent of the jelly surrounding the ovum, a red glycoprotein with a carotenoid prosthetic group. This protein, to which the name ovorubin has been given, has a high stability to denaturation by heat and by adsorption at interfaces. It is partially utilized during development of the ovum, although about two-thirds of the original ovorubin content of the egg is found in the visceral hump of the newly hatched animal. The carotenoid component is probably an ester or ether of astaxanthin, highly labile to alkali in the cold. The minimum molecular weight, calculated from the carotenoid content, lies in the region of 330000. The carbohydrate component represents about 20% of the molecule. The carotenoid and the glycoprotein may readily be separated and recombined. Experiments on the apo-glycoprotein and the reconstituted carotenoprotein indicate that the carotenoid stabilizes the native configuration of the protein structure. It is suggested that stabilization of the configurations of protein molecules may be one of the roles of carotenoids in nature.
IT is well known that the majority of aquatic animals mobilize carotenoids into the ova during the spawning season; but probable reasons for this have only recently become apparent. The important work of Steven1 has shown that lutein and astaxanthin are transferred quantitatively from the yolk of brown trout (Salmo trutta) eggs to the developing embryo, where they are incorporated into the chromatophores thus ensuring that the young larvæ are very soon fully equipped from this point of view. None of the astaxanthin or lutein is used up during embryonic development, which suggests that these pigments play little, if any, `metabolic' part in this process. The traces of beta-carotene present do disappear during development, probably owing to conversion into vitamin A. Morton and Rosen2 have shown that no carotenoid is used up during the embryonic development of salmon.
The pigmentation of terrestrial invertebrates has been shown to function in the optimization of solar warming, yet pigmented aquatic invertebrates have never been examined for the ability to utilize solar illumination in a similar manner. The degree of carotenoid pigmentation in calanoid copepods is easily quantified, and comparisons between populations suggest that variation in copepod pigmentation is related to variation in water temperature, with the most darkly pigmented copepods occurring in the coldest lakes. Darkly pigmented copepods show significantly higher metabolic rates in the light than in the dark, whereas lightly pigmented copepods do not. The metabolic experiments provide evidence that dark coloration is adaptive to cold-water copepods because it facilitates significant internal warming of tissues by sunlight. This hypothesis may be used to explain the pigmentation of many other cold-water invertebrates.
The Biochemistry of Carotenoids. 1: Plants
- T W Goodwin
T.W. Goodwin, The Biochemistry of Carotenoids. 1: Plants, Chapman and Hall, NY, 1980.
Carotenoids in mollusca: approaching the function
- Vershinin