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Carotenoids
Kinds of Carotenoids Terms modified by Carotenoids Selected AbstractsCarotenoid and melanin-based ornaments signal similar aspects of male quality in two populations of the common yellowthroatFUNCTIONAL ECOLOGY, Issue 1 2010Peter O. Dunn Summary 1.,Female preferences for particular male ornaments may shift between populations as a consequence of ecological differences that change the reliability and detectability of the ornament, but few studies have examined how ornaments function in different populations. 2.,We examined the signalling function of male plumage ornaments in a warbler, the common yellowthroat (Geothlypis trichas), breeding in New York (NY) and Wisconsin (WI), USA. Males have two prominent ornaments: a black facial mask pigmented with melanin and a yellow bib pigmented by carotenoids. Previous studies in WI indicate that the size of the mask, and not the bib, is primarily related to female choice and male reproductive success. In NY, however, the pattern is reversed and attributes of the bib (size and colour), and not the mask, are the target of sexual selection. 3.,We found that brightness of the yellow bib was the best signal of humoral immunity (immunoglobulin G) in NY and mask size was the best signal in WI, after controlling for breeding experience and capture date. Thus, similar aspects of male quality appeared to be signalled by different ornaments in different populations. 4.,There was no difference between populations in the level of plasma carotenoids or the prevalence of malarial parasites, which may affect the costs and benefits of choosing males with particular ornaments in each location. 5.,Even though females in different populations prefer different ornaments produced by different types of pigments, these ornaments appear to be signalling similar aspects of male quality. Our results caution against inferring the function of particular ornaments based simply on their type of pigment. [source] Carotenoid and protein supplementation have differential effects on pheasant ornamentation and immunityJOURNAL OF EVOLUTIONARY BIOLOGY, Issue 1 2007H. G. SMITH Abstract A currently popular hypothesis states that the expression of carotenoid-dependent sexual ornaments and immune function may be correlated because both traits are positively affected by carotenoids. However, such a correlation may arise for another reason: it is well known that immune function is dependent on nutritional condition. A recent study has suggested that the expression of ornaments may too depend on nutritional condition, as males in good nutritional condition are better at assimilating and/or modulating carotenoids. Thus, carotenoid-dependent ornaments and immune function may be correlated because both are dependent on nutritional condition. To elucidate if, and how, ornamentation and immune function are linked, pheasant diets were supplemented with carotenoid and/or protein in a fully factorial experiment. Carotenoid treatment affected wattle coloration and tail growth, but not cellular or humoral immunity. Immunity was unrelated to males' initial ornamentation including wattle colour. Males in better body condition, measured as residual mass, increased their wattle coloration more when carotenoid supplemented. Protein positively affected humoral but not cellular immunity, but had no effect on ornaments. Cellular, but not humoral, immunity increased with male body condition. Thus, there was no evidence that an immune-stimulatory effect of carotenoids resulted in wattle coloration honestly signalling immune function, but wattle coloration may still signal male body condition. [source] Proximate mechanisms of variation in the carotenoid-based plumage coloration of nestling great tits (Parus major L.)JOURNAL OF EVOLUTIONARY BIOLOGY, Issue 1 2003B. Tschirren Abstract Many vertebrates use carotenoid-based signals in social or sexual interactions. Honest signalling via carotenoids implies some limitation of carotenoid-based colour expression among phenotypes in the wild, and at least five limiting proximate mechanisms have been hypothesized. Limitation may arise by carotenoid-availability, genetic constraints, body condition, parasites, or detrimental effects of carotenoids. An understanding of the relative importance of the five mechanisms is relevant in the context of natural and sexual selection acting on signal evolution. In an experimental field study with carotenoid supplementation, simultaneous cross-fostering, manipulation of brood size and ectoparasite load, we investigated the relative importance of these mechanisms for the variation in carotenoid-based coloration of nestling great tits (Parus major). Carotenoid-based plumage coloration was significantly related to genetic origin of nestlings, and was enhanced both in carotenoid-supplemented nestlings, and nestlings raised in reduced broods. We found a tendency for ectoparasite-induced limitation of colour expression and no evidence for detrimental effects of carotenoids on growth pattern, mortality and recruitment of nestlings to the local breeding population. Thus, three of the five proposed mechanisms can generate individual variation in the expression of carotenoid-based plumage coloration in the wild and thus could maintain honesty in a trait potentially used for signalling of individual quality. [source] Influence of Lactation History on Breast Nipple Aspirate Fluid Yields and Fluid CompositionTHE BREAST JOURNAL, Issue 2 2005Zora Djuric PhD Abstract: Analysis of nipple aspirate fluid (NAF) can be useful for understanding the impact that various lifestyle factors have on the biology of the breast. In this study, breast NAF was obtained at baseline from premenopausal women who volunteered for a dietary intervention trial. The influence of lactation history on both fluid yields and fluid composition was explored. We examined the levels of fat-soluble micronutrients (tocopherols, carotenoids, retinol), one lipid oxidation product (8-isoprostane), cholesterol, and protein in NAF. Roughly half of the women in the trial had never lactated, but this did not affect fluid yields appreciably. Carotenoid and tocopherol levels were significantly higher in NAF from women who lactated 6 months or more versus women who had lactated for shorter periods of time or never, but 8-isoprostane, protein, and cholesterol levels were not affected appreciably by lifetime lactation history. Longer times after weaning were associated with higher cholesterol levels, and there also was a suggestion the fat-soluble micronutrients declined with time after weaning. This is of interest since high cholesterol levels in breast fluid have been associated with an increased breast cancer risk, while carotenoids and tocopherols are thought to be protective. The results of this study provide further evidence of the potential benefits of prolonged lactation via its influence on NAF composition., [source] Lycopene, a Carotenoid, Attenuates Cyclosporine-Induced Renal Dysfunction and Oxidative Stress in RatsBASIC AND CLINICAL PHARMACOLOGY & TOXICOLOGY, Issue 6 2007Ahmet Ate, ahin Adult male Sprague-Dawley rats were randomly divided into four groups. The control group received physiological saline; animals in the lycopene group received only lycopene (10 mg/kg); animals in the cyclosporine A group received only cyclosporine A (15 mg/kg) and animals in cyclosporine plus lycopene group received cyclosporine and lycopene for 21 days. The effects of lycopene on cyclosporine A-induced nephrotoxicity were evaluated by plasma creatinine, urea, sodium and calcium concentrations; kidney tissue thiobarbituric acid reactive species, reduced glutathione (GSH), glutathione peroxidase (GSH-Px) and catalase activities and histopatological examinations. Administration of cyclosporine A to rats induced a marked renal failure, characterized with a significant increase in plasma creatinine and urea concentrations. Cyclosporine A also induced oxidative stress as indicated by increased kidney tissue concentrations of thiobarbituric acid reactive species and GSH, and reduced activities of GSH-Px and catalase. Moreover, the kidneys of cyclosporine A-treated rats showed tubular necrosis, degeneration, dilatation, thickened basement membranes, luminal cast formation and inter-tubular fibrosis. Lycopene markedly reduced elevated plasma creatinine, urea levels and counteracted the deleterious effects of cyclosporine A on oxidative stress markers. In addition, lycopene ameliorated cyclosporine A-induced pathological changes including tubular necrosis, degeneration, thickened basement membranes and inter-tubular fibrosis when compared to the alone cyclosporine A group. These data indicate that the natural antioxidant lycopene might have protective effect against cyclosporine-induced nephrotoxicity and oxidative stress in rat. [source] Incubation Feeding and Nest Attentiveness in a Socially Monogamous Songbird: Role of Feather Colouration, Territory Quality and Ambient EnvironmentETHOLOGY, Issue 7 2010Beata Matysioková Parental investment and environmental conditions determine reproductive success in wild-ranging animals. Parental effort during incubation, and consequently factors driving it, has profound consequences for reproductive success in birds. The female nutrition hypothesis states that high male feeding enables the incubating female to spend more time on eggs, which can lead to higher hatching success. Moreover, both male and female parental investment during incubation might be signalled by plumage colouration. To test these hypotheses, we investigated relationships between male and female incubation behaviour and carotenoid and melanin-based plumage colouration, territory quality and ambient temperature in the Great Tit Parus major. We also studied the effect of female incubation behaviour on hatching success. Intensity of male incubation feeding increased with lower temperatures and was higher in territories with more food supply, but only in poor years with low overall food supply. Female nest attentiveness increased with lower temperatures. Plumage colouration did not predict incubation behaviour of either parent. Thus, incubation behaviour of both parents was related mainly to environmental conditions. Moreover, there was no relationship between male incubation feeding, female nest attentiveness and hatching success. Consequently, our data were not consistent with the female nutrition hypothesis. [source] The role of melanin- and carotenoid-based plumage coloration in nest defence in the Great TitETHOLOGY, Issue 7 2007Javier Quesada Although plumage coloration is recognized to convey valuable information about the bearer's parental abilities, few studies have explored the relationship between coloration and nest defence. In this study in Great Tit Parus major, we analysed the relationship between nest defence and melanin- as well as carotenoid-based plumage coloration, after controlling for ecological variables known to influence nest defence. A principal components analysis was applied to classify birds according to how vigorously they defended the nest, and the intensity of nest defence was tested against plumage coloration. Males with a large black tie defended their nests more vigorously, but no such effect was found for yellow breast coloration. This suggests that melanin-based coloration in the Great Tit is associated with aggression, including both dominance-aggression and nest defence, whereas carotenoid-based coloration is not. The challenge in future studies will be to demonstrate whether females use this trait as an ornament to assess male quality and whether they trade off between the different ornaments a male may exhibit. [source] Synthesis of a Highly Unsaturated, Stable Hydroxy Peroxide: A Yellow [lrarr2] Blue Color-Changing Carotenoid Oxidation Product with Leuco Dye PropertiesEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 24 2010He Li Abstract A stable, highly unsaturated hydroxy peroxide was synthesized by reacting a common food color carotenoid with FeCl3 in air. The obtained pale-yellow carotenoid hydroxy peroxide is easily converted into a blue, cationic polyene , then changes back to the yellow compound, showing the same characteristically dichromic properties like polycyclic, aromatic leuco dyes. [source] Functional implications of pigments bound to a cyanobacterial cytochrome b6f complexFEBS JOURNAL, Issue 2 2005Stephan-Olav Wenk A highly purified cytochrome b6f complex from the cyanobacterium Synechocystis sp. PCC 6803 selectively binds one chlorophyll a and one carotenoid in analogy to the recent published structure from two other b6f complexes. The unknown function of these pigments was elucidated by spectroscopy and site-directed mutagenesis. Low-temperature redox difference spectroscopy showed red shifts in the chlorophyll and carotenoid spectra upon reduction of cytochrome b6, which indicates coupling of these pigments with the heme groups and thereby with the electron transport. This is supported by the correlated kinetics of these redox reactions and also by the distinct orientation of the chlorophyll molecule with respect to the heme cofactors as shown by linear dichroism spectroscopy. The specific role of the carotenoid echinenone for the cytochrome b6f complex of Synechocystis 6803 was elucidated by a mutant lacking the last step of echinenone biosynthesis. The isolated mutant complex preferentially contained a carotenoid with 0, 1 or 2 hydroxyl groups (most likely 9- cis isomers of ,-carotene, a monohydroxy carotenoid and zeaxanthin, respectively) instead. This indicates a substantial role of the carotenoid , possibly for strucure and assembly , and a specificity of its binding site which is different from those in most other oxygenic photosynthetic organisms. In summary, both pigments are probably involved in the structure, but may also contribute to the dynamics of the cytochrome b6f complex. [source] Interallelic complementation provides genetic evidence for the multimeric organization of the Phycomyces blakesleeanus phytoene dehydrogenaseFEBS JOURNAL, Issue 3 2002Catalina Sanz The Phycomyces blakesleeanus wild-type is yellow, because it accumulates ,-carotene as the main carotenoid. A new carotenoid mutant of this fungus (A486) was isolated, after treatment with ethyl methane sulfonate (EMS), showing a whitish coloration. It accumulates large amounts of phytoene, small quantities of phytofluene, ,-carotene and neurosporene, in decreasing amounts, and traces of ,-carotene. This phenotype indicates that it carries a leaky mutation affecting the enzyme phytoene dehydrogenase (EC 1.3.-.-), which is specified by the gene carB. Biochemical analysis of heterokaryons showed that mutant A486 complements two previously characterized carB mutants, C5 (carB10) and S442 (carB401). Sequence analysis of the carB gene genomic copy from these three strains revealed that they are all altered in the gene carB, giving information about the nature of the mutation in each carB mutant allele. The interallelic complementation provides evidence for the multimeric organization of the P. blakesleeanus phytoene dehydrogenase. [source] Astaxanthin formation in the marine photosynthetic bacterium Rhodovulum sulfidophilum expressing crtI, crtY, crtW and crtZFEMS MICROBIOLOGY LETTERS, Issue 1 2006Daikichi Mukoyama Abstract This study reports the production of astaxanthin in the photosynthetic bacterium Rhodovulum sulfidophilum, which has adequate precursor pools and storage capabilities for heterologous carotenoid production. Chemical mutagenesis was carried out using ethylmethane sulfonate to produce mutants with a modified carotenoid biosynthesis pathway downstream of phytoene. Stable green- and gray-colored mutants were selected. Green mutants contained neurosporene or chloroxanthin as their major carotenoid (>90%), while the gray mutants accumulated phytoene. We previously demonstrated the production of ,-carotene in Rhodovulum sulfidophilum by cloning the Erythrobacter longus crtI (phytoene dehydrogenase) and crtY (lycopene cyclase) genes. In the present study, an expression vector for astaxanthin production was constructed that contained the Paracoccus crtW (,-carotene oxygenase) and crtZ (,-carotene hydroxylase) genes in addition to the E. longus crtI and crtY genes. A transconjugant, which can synthesize astaxanthin, was successfully generated (2.0 ,g g,1 DCW). [source] Parasites, testosterone and honest carotenoid-based signalling of healthFUNCTIONAL ECOLOGY, Issue 5 2007F. MOUGEOT Summary 1Among the commonest sexual signals of birds are the red-yellow traits pigmented by carotenoids, but how they reliably advertise individual quality remain poorly understood. Here we tested the hypothesis that carotenoid-based signalling is enhanced by testosterone but reduced by parasites, and that the dual action of testosterone on ornament expression and parasite resistance ensures reliable signalling. 2Tetraonid birds such as the red grouse Lagopus lagopus scoticus have bright red combs pigmented by carotenoids, which function in intra- and inter-sexual selection. In separate experiments, we manipulated a main nematode parasite, Trichostrongylus tenuis (using deparasitation and re-infection) and testosterone (using testosterone or combined Flutamide/ATD treatments) in free-living males and investigated effects on plasma carotenoids and comb colour. 3In untreated males, comb redness positively correlated with plasma carotenoids, testosterone concentration and condition. Plasma carotenoids and comb redness both negatively correlated with T. tenuis abundance. 4Plasma carotenoids decreased in response to a challenge from T. tenuis, but increased when parasites were reduced. Testosterone enhanced comb redness, but tended to deplete plasma carotenoids. Combined Flutamide and ATD treatment had no significant effects on comb colour or plasma carotenoids, indicating that testosterone effects might be direct. 5Our experiments show contrasted effects of testosterone and nematode parasites on carotenoid-based ornamentation. Testosterone and parasites have well documented interactions in the study model. These, together with the opposite effects that testosterone and parasites have on carotenoid availability and use, would shape optimal levels of signalling, depending on individual quality, and might ensure reliable signalling. 6Carotenoid-based and testosterone-dependent traits have rarely been linked. Our study provides such a connection and shows that investigating how parasites, testosterone and carotenoids interact helps in the understanding of the evolution and maintenance of honest carotenoid-based signals of health. [source] Maternal carotenoid supplementation does not affect breeding performance in the Great Tit (Parus major)FUNCTIONAL ECOLOGY, Issue 4 2007VLADIMÍR REME Summary 1Carotenoids are micronutrients with many beneficial health-related effects. They are effective antioxidants and stimulants of the immune system. Carotenoids cannot be synthesized in animals and must be obtained from food. As such, they may limit reproductive output and performance, and on the proximate level mediate reproductive trade-offs. 2We studied carotenoid limitation in wild Great Tits (Parus major) by supplementing prelaying and laying females with lutein, the most abundant carotenoid in this species. We followed the effects of this supplementation on egg yolk carotenoid composition, and offspring and parental performance. 3Females transferred the supplemented lutein into egg yolks, increasing lutein concentration to the upper limit of naturally occurring concentrations in control pairs. Concentrations of zeaxanthin, ,-carotene and ,-carotene did not differ between supplemented and control pairs. 4Effects on offspring and parental performance were generally absent or weak. There were no effects on timing of laying, clutch size, hatching success, nestling survival, nestling mass (day 6 and 14), tarsus length or T-cell mediated immune response. Males on supplemented nests fed their young more than those on control nests. There was no positive effect on female feeding or mass. 5Negligible effects of lutein supplementation on offspring and parental performance might be explained by high natural abundance of carotenoids or other antioxidants, where additional carotenoids bear no strong advantage to the birds. Additionally, conflicting results of different studies may be explained by species-specific features of their life-histories. [source] Carotenoid accumulation strategies for becoming a colourful House Finch: analyses of plasma and liver pigments in wild moulting birdsFUNCTIONAL ECOLOGY, Issue 4 2006K. J. MCGRAW Summary 1Male House Finches (Carpodacus mexicanus) colour their sexually selected plumage with carotenoid pigments, and there has been much interest in the factors that affect their ability to become bright red rather than drab yellow. 2There is good support for the notions that health, nutritional condition and total carotenoid intake influence colour expression, but there are also suggestions that acquiring particular types of carotenoids from the diet may be important for developing red plumage. 3We used high-performance liquid chromatography (HPLC) to analyse the types and amounts of endogenous (in plasma and liver) and integumentary (in newly grown feathers) carotenoids in a wild, native population of moulting male and female House Finches from the south-western United States to determine the carotenoid-accumulation strategies for becoming optimally colourful. 4Four plant carotenoids , lutein, zeaxanthin, ,-cryptoxanthin and ,-carotene , were detected in plasma and liver. However, as was found previously, 11 carotenoids were observed in colourful plumage, with xanthophylls (e.g. lutein, dehydrolutein) predominant in yellow feathers and ketocarotenoids (e.g. adonirubin, 3-hydroxy-echinenone) in red feathers. This indicates endogenous modification of ingested carotenoids. 5Birds that accumulated more of one type of carotenoid in plasma and liver did not necessarily accumulate more of all other types, suggesting that individuals are not employing a simple ,more is better' strategy for coloration. Instead, when forward stepwise regression was used to examine the ability of individual types of carotenoids in plasma and liver to explain variation in red plumage pigments and plumage redness, we found that the lone variable remaining in all models was ,-cryptoxanthin concentration. 6This supports the idea that, unlike some other songbirds (e.g. yellow Carduelis finches), there is a specialized biochemical strategy that male House Finches follow to become red and most sexually attractive , to accumulate as much ,-cryptoxanthin in the body as possible. ,-Cryptoxanthin is a less common dietary carotenoid than the typical xanthophylls and carotenes in grains and fruits and may be limited enough in the diet that, to become colourful, House Finches might adopt selective foraging strategies for the most ,-cryptoxanthin-rich foods. [source] How feather colour reflects its carotenoid contentFUNCTIONAL ECOLOGY, Issue 4 2003Lauri Saks Summary 1Many birds sequester carotenoid pigments in colourful patches of feathers to advertise or compete for mates. Because carotenoids can be scarce in nature and serve valuable physiological functions, only the highest-quality individuals are thought to acquire or allocate more pigments for use in sexual displays. 2A critical but rarely tested assumption of carotenoid-based signals is that the colour of pigmented feather patches directly reveals the total amount of carotenoids contained within them. 3We studied the relationship between carotenoid-based coloration (hue, chroma and brightness) and the pigment content of tail feathers in wild-caught and captive male greenfinches (Carduelis chloris[Linnaeus]). Greenfinches incorporate two main carotenoids , canary xanthophylls A and B , into feathers to develop yellow patches of colour in their tail. 4Variation in feather carotenoid content explained 32,51% of variation in chroma and hue of the yellow parts of tail feathers, while feather brightness was not significantly related to carotenoid concentration. Hence, chroma and hue appear good candidates to indicate feather carotenoid content. 5Birds with the most colourful feathers deposited significantly more of both canary xanthophylls into plumage. Thus, there does not appear to be a specific biochemical strategy for becoming colourful in greenfinches; males instead follow the general decision rule to deposit as many xanthophylls as possible into feathers to become yellow. [source] Responses of plants in polar regions to UVB exposure: a meta-analysisGLOBAL CHANGE BIOLOGY, Issue 11 2009KEVIN K. NEWSHAM Abstract We report a meta-analysis of data from 34 field studies into the effects of ultraviolet B (UVB) radiation on Arctic and Antarctic bryophytes and angiosperms. The studies measured plant responses to decreases in UVB radiation under screens, natural fluctuations in UVB irradiance or increases in UVB radiation applied from fluorescent UV lamps. Exposure to UVB radiation was found to increase the concentrations of UVB absorbing compounds in leaves or thalli by 7% and 25% (expressed on a mass or area basis, respectively). UVB exposure also reduced aboveground biomass and plant height by 15% and 10%, respectively, and increased DNA damage by 90%. No effects of UVB exposure were found on carotenoid or chlorophyll concentrations, net photosynthesis, Fv/Fm or ,PSII, belowground or total biomass, leaf mass, leaf area or specific leaf area (SLA). The methodology adopted influenced the concentration of UVB absorbing compounds, with screens and natural fluctuations promoting significant changes in the concentrations of these pigments, but lamps failing to elicit a response. Greater reductions in leaf area and SLA, and greater increases in concentrations of carotenoids, were found in experiments based in Antarctica than in those in the Arctic. Bryophytes typically responded in the same way as angiosperms to UVB exposure. Regression analyses indicated that the percentage difference in UVB dose between treatment and control plots was positively associated with concentrations of UVB absorbing compounds and carotenoids, and negatively so with aboveground biomass and leaf area. We conclude that, despite being dominated by bryophytes, the vegetation of polar regions responds to UVB exposure in a similar way to higher plant-dominated vegetation at lower latitudes. In broad terms, the exposure of plants in these regions to UVB radiation elicits the synthesis of UVB absorbing compounds, reduces aboveground biomass and height, and increases DNA damage. [source] Ozone exposure over two growing seasons alters root-to-shoot ratio and chemical composition of birch (Betula pendula Roth)GLOBAL CHANGE BIOLOGY, Issue 10 2003K. Yamaji Abstract Physiological and chemical responses of 17 birch (Betula pendula Roth) clones to 1.5,1.7 × ambient ozone were studied in an open-field experiment over two growing seasons. The saplings were studied for growth, foliar visible injuries, net photosynthesis, stomatal conductance, and chlorophyll, carotenoid, Rubisco, total soluble protein, macronutrient and phenolic concentrations in leaves. Elevated ozone resulted in growth enhancement, changes in shoot-to-root (s/r) ratio, visible foliar injuries, reduced stomatal conductance, lower late-season net photosynthesis, foliar nutrient imbalance, changes in phenolic composition, and reductions in pigment, Rubisco and soluble protein contents indicating accelerated leaf senescence. Majority of clones responded to ozone by changing C allocation towards roots, by stomatal closure (reduced ozone uptake), and by investment in low-cost foliar antioxidants to avoid and tolerate ozone stress. A third of clones, showing increased s/r ratio, relied on inducible efficient high-cost antioxidants, and enhanced leaf production to compensate ozone-caused decline in leaf-level net photosynthesis. However, the best ozone tolerance was found in two s/r ratio-unaffected clones showing a high constitutive amount of total phenolics, investment in low-cost antioxidants and N distribution to leaves, and lower stomatal conductance under ozone stress. The results highlight the importance of phenolic compounds in ozone defence mechanisms in the birch population. Depending on the genotype, ozone detoxification was improved by an increase in either efficient high-cost or less efficient low-cost antioxidative phenolics, with close connections to whole-plant physiology. [source] Preen waxes do not protect carotenoid plumage from bleaching by sunlightIBIS, Issue 2 2008ADRIAN SURMACKI The plumage coloration of wild birds often changes during the breeding season. One of the possible reasons for this is that sunlight, and particularly ultraviolet (UV) wavelengths, degrades the pigments responsible for plumage coloration. It has been suggested that birds may apply preen wax to feathers to protect feathers from bleaching. This hypothesis is tested by exposing carotenoid-based breast feathers of Great Tits to ambient light, light filtered to exclude UV and darkness. Preen waxes were experimentally removed from feather samples and the effect of light on coloration of treatment and control feathers compared. Ambient light had an effect on feather colour but preen wax did not. Feathers exposed to sun gradually became less saturated and hues shifted towards shorter wavelengths. This was not apparent in control feathers kept in darkness. Feathers exposed to full-spectra sunlight faded more than those that were kept in light with UV wavelengths removed. There was a decrease in brightness of feathers in both experimental and control groups, which was assumed to be an effect of dirt accumulation. This experiment confirmed earlier suspicions regarding the detrimental effects of UV irradiation on carotenoid-based coloration of avian feathers but failed to show any protective function of preen waxes. The possible consequences of these mechanisms of colour change for birds with regard to mating strategies are discussed. [source] The carotenoid-based plumage coloration of adult Blue Tits Cyanistes caeruleus correlates with the health status of their broodIBIS, Issue 4 2006SERGIO HIDALGO-GARCIA The Blue Tit Cyanistes caeruleus is a passerine bird in which both sexes provide substantial care to the offspring and display conspicuous carotenoid-based plumage coloration. It has been shown that carotenoid-based coloration in birds reflects both individual quality and foraging ability. Because the body condition of nestlings usually depends on the capacity of their parents to feed them, I predicted that, independent of sex, those individuals with the most exaggerated carotenoid-based plumage coloration should raise offspring in better health. I found that although, in my study population, the smallest females were paired with the largest males, the brightest females were paired with the brightest and most intensely coloured males. I used body condition and T-cell-mediated immune response of nestlings as measures of their health status. Generalized mixed models showed that brighter and more-yellow adults reared offspring in better than average condition and immune response. Older males and smaller females were also able to raise offspring with better immune response. All these results suggest that the carotenoid-based plumage coloration of parents is somehow linked with individual quality, as it presents a significant and positive correlation with the health status of their growing chicks. Thus, the brightest and more intensely coloured individuals raised the healthiest offspring. [source] Changes in total carotenoid content at different stages of traditional processing of yellow-fleshed cassava genotypesINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 12 2009Busie Maziya-Dixon Abstract The changes in content of total carotenoid at each stage of processing cassava storage roots were investigated with three improved yellow-fleshed cassava varieties (TMS 94/0006, TMS 01/1235 and TMS 01/1371) grown in 2005/2006 in a randomised complete block design with two replications at Ibadan, Nigeria. When the cassava roots were grated to a mash, results obtained indicate that there was a significant reduction in total carotenoid content for all the genotypes. The reduction was highest for TMS 01/1235 (1.20 ,g g,1), intermediate for TMS 01/1371 (0.78 ,g g,1) and least for TMS 94/0006 (0.35 ,g g,1). In most cases, we observed higher total carotenoid concentration, especially when the intermediate step involved pressing to remove excess water, and during roasting compared with the initial concentration in the raw cassava storage roots. In conclusion, grating, drying and cooking to a paste resulted in reduction of total carotenoid content, while roasting and pressing resulted in higher carotenoid concentration. A change in total carotenoid content during processing depends on variety, processing method, especially unit operation and the initial total carotenoid content of the variety. [source] Changes in carotenoid, physicochemical and sensory values of deep-fried carrot chips during storageINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 5 2003Ahmad Sulaeman Summary Deep-fried carrot chips were packaged in layered film (metallized polyester and linear low-density polyethylene) pouches under a partial vacuum of <1% O2 concentration. Packages containing chips were stored in dark chambers at three conditions: 0,1 °C, 94,98% relative humidity (r.h.) (A); 22,23 °C, 31,45% r.h. (B); and 29,31 °C, 89,93% r.h. (C) for 0,5 months. Retention of , - and , -carotene content and vitamin A activity were >82% over 5 months for all conditions. Colour values (L, a, b) were unchanged over 5 months for A and B, but decreased gradually (P < 0.05) for C. No changes in moisture content, fat content, water activity, texture values and sensory values were observed over time for A and B, but changed (P < 0.05) for C. No sensory differences were observed by condition or time in colour. Carrot chips, packaged in partially vacuumed opaque pouches, can be stored for at least 5 months at 0,1 °C, 94,98% r.h. or 22,23 °C, 31,45% r.h. [source] Ultraviolet-blue reflectance of some nestling plumage patches mediates parental favouritism in great tits Parus majorJOURNAL OF AVIAN BIOLOGY, Issue 3 2008Ismael Galván The colouration exhibited by nestling birds is generally cryptic, but in some species it has a conspicuous appearance. The adaptive function of these nestling displays is poorly known, especially in altricial species. We performed an experimental study in which the ultraviolet-blue reflectance of the carotenoid-based plumage of great tit Parus major nestlings was reduced in order to find possible evidence of parental favouritism. Tarsus length increment in a three-day period was significantly lower in manipulated nestlings than in their control siblings. As tarsus length may be a good predictor of survival, the parents may increase their fitness return by investing more in those nestlings reflecting more in the UV-blue spectral region. Interestingly, this effect was only found in a yellow patch located at the nape of nestlings that has been previously overlooked, as all the studies on plumage colouration in this species have focused on the breast plumage. Some quality indicators are proposed for the colour of nestling plumage, though the possibility exists that selection may operate through aspects of signal efficacy instead of aspects of signal content. [source] Geographic variation in the function of ornaments in the common yellowthroat Geothlypis trichasJOURNAL OF AVIAN BIOLOGY, Issue 1 2008Peter O. Dunn We used controlled aviary experiments to study the role of male ornaments in male-male competition and female choice in the common yellowthroat Geothlypis trichas, a sexually dichromatic warbler. Previous aviary studies in Wisconsin, USA, indicated that males with larger black facial masks were dominant over males with smaller masks and preferred by females in mate choice experiments. In this study, we replicated those experiments in a population in New York, USA, where male mating success was related more consistently to the size of the yellow bib (throat, breast, and belly) than to the size of the mask. Similar to the study in Wisconsin, we found that males with larger masks were more likely to be dominant in New York, however, we found that males with larger bibs were preferred by females in New York, and there was no significant preference for males with larger masks. These results are consistent with the hypothesis that carotenoid-based ornaments are selected by female choice and melanin-based ornaments are selected by male-male competition. However, the pattern of female choice appears to vary between New York and Wisconsin. This geographic difference could be related to a variety of environmental factors (habitat, carotenoid and parasite abundance) that affect the costs and benefits of choosing males with particular ornaments in each location. [source] Carotenoid coloration in great black-backed gull Larus marinus reflects individual qualityJOURNAL OF AVIAN BIOLOGY, Issue 1 2006Kai O. Kristiansen Carotenoids are a large group of biochemicals, with similar properties, synthesised by bacteria, fungi, algae and plants. Vertebrates obtain these biologically active pigments through the diet, and they are a disproportionately common component of animal colour signals and play important roles in immune functions and as antioxidants. Carotenoids are believed to be a limited resource and because of the trade-off between allocation of carotenoids to signals and to other functions, carotenoid based signals are often thought to be handicap signals. The purpose of this study was to investigate the signalling potential of carotenoid-based tissue coloration in the great black-backed gull Larus marinus. The intensity of carotenoid-based coloration in bill, gape and eye-ring coloration was investigated in relation to body condition, reproductive parameters, levels of immune activity, and sexual dimorphism. In males there was a positive relationship between colour intensity and body condition, but in females no such relationship was found. However, females with high colour intensity had larger eggs and clutches. Additionally, females with high red scores tended to have high density of circulating lymphocytes. There was no sexual dimorphism in coloration and there was a negative relationship between colour intensity and sampling time, which indicates that this coloration is most intensely expressed early in the breeding season. The results in this study suggest that carotenoid-based coloration in great black-backed gull are partly condition dependent and reveal information about individual quality in both males an females. Hence, it might have evolved as an important signal for assessing the quality of potential mates. [source] Red-winged blackbirds Agelaius phoeniceus use carotenoid and melanin pigments to color their epauletsJOURNAL OF AVIAN BIOLOGY, Issue 6 2004Kevin J. McGraw Over the past three decades, the red-winged blackbird Agelaius phoeniceus has served as a model species for studies of sexual selection and the evolution of ornamental traits. Particular attention has been paid to the role of the colorful red-and-yellow epaulets that are striking in males but reduced in females and juveniles. It has been assumed that carotenoid pigments bestow the brilliant red and yellow colors on epaulet feathers, but this has never been tested biochemically. Here, we use high-performance liquid chromatography (HPLC) to describe the pigments present in these colorful feathers. Two red ketocarotenoids (astaxanthin and canthaxanthin) are responsible for the bright red hue of epaulets. Two yellow dietary precursors pigments (lutein and zeaxanthin) are also present in moderately high concentrations in red feathers. After extracting carotenoids, however, red feathers remained deep brown in color. HPLC tests show that melanin pigments (primarily eumelanin) are also found in the red-pigmented barbules of epaulet feathers, at an approximately equal concentration to carotenoids. This appears to be an uncommon feature of carotenoid-based ornamental plumage in birds, as was shown by comparable analyses of melanin in the yellow feathers of male American goldfinches Carduelis tristis and the red feathers of northern cardinals Cardinalis cardinalis, in which we detected virtually no melanins. Furthermore, the yellow bordering feathers of male epaulets are devoid of carotenoids (except when tinged with a carotenoid-derived pink coloration on occasion) and instead are comprised of a high concentration of primarily phaeomelanin pigments. The dual pigment composition of red epaulet feathers and the melanin-only basis for yellow coloration may have important implications for the honesty-reinforcing mechanisms underlying ornamental epaulets in red-winged blackbirds, and shed light on the difficulties researchers have had to date in characterizing the signaling function of this trait. As in several other birds, the melanic nature of feathers may explain why epaulets are used largely to settle aggressive contests rather than to attract mates. [source] Influence of oxidative stress and grains on sclerotial biomass and carotenoid yield of Penicillium sp.JOURNAL OF BASIC MICROBIOLOGY, Issue 4 2010Abstract Oxidative stress and grains were evaluated for carotenoid production by solid-state fermentation using Penicillium sp. PT95. When the fungus was grown at high oxidative stress, its sclerotial biomass and carotenoid content in sclerotia increased significantly with respect to low oxidative stress (P < 0.01). High oxidative stress also caused a statistically significant increase in carotenoid yield as compared with low oxidative stress (P < 0.01). Both the sclerotial biomass and the amount of carotenoid accumulated in sclerotia of strain PT95 were strongly dependent on the grain medium used. Among the grain media tested under high oxidative stress, buckwheat medium gave the highest content of carotenoid in sclerotia (828 ,g/g dry sclerotia), millet medium gave respectively the highest sclerotial biomass (12.69 g/100 g grain) and carotenoid yield (10.152 mg/100 g grain). (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Astaxanthin protects mesangial cells from hyperglycemia-induced oxidative signaling,JOURNAL OF CELLULAR BIOCHEMISTRY, Issue 6 2008Emiko Manabe Abstract Astaxanthin (ASX) is a carotenoid that has potent protective effects on diabetic nephropathy in mice model of type 2 diabetes. In this study, we investigated the protective mechanism of ASX on the progression of diabetic nephropathy using an in vitro model of hyperglycemia, focusing on mesangial cells. Normal human mesangial cells (NHMCs) were cultured in the medium containing normal (5 mM) or high (25 mM) concentrations of D -glucose. Reactive oxygen species (ROS) production, the activation of nuclear transcription factors such as nuclear factor kappa B (NF,B) and activator protein-1 (AP-1), and the expression/production of transforming growth factor-beta 1 (TGF,1) and monocyte chemoattractant protein-1 (MCP-1) were evaluated in the presence or absence of ASX. High glucose (HG) exposure induced significant ROS production in mitochondria of NHMCs, which resulted in the activation of transcription factors, and subsequent expression/production of cytokines that plays an important role in the mesangial expansion, an important event in the pathogenesis of diabetic nephropathy. ASX significantly suppressed HG-induced ROS production, the activation of transcription factors, and cytokine expression/production by NHMCs. In addition, ASX accumulated in the mitochondria of NHMCs and reduced the production of ROS-modified proteins in mitochondria. ASX may prevent the progression of diabetic nephropathy mainly through ROS scavenging effect in mitochondria of mesangial cells and thus is expected to be very useful for the prevention of diabetic nephropathy. J. Cell. Biochem. 103: 1925,1937, 2007. © 2007 Wiley-Liss, Inc. [source] ,-cryptoxanthin stimulates cell differentiation and mineralization in osteoblastic MC3T3-E1 cellsJOURNAL OF CELLULAR BIOCHEMISTRY, Issue 6 2005Satoshi Uchiyama Abstract The effect of ,-cryptoxanthin, a kind of carotenoid, on cell differentiation and mineralization in osteoblastic MC3T3-E1 cells was investigated. Cells were cultured for 72 h in a minimum essential medium containing 10% fetal bovine serum (FBS), and the cells with subconfluency were changed to a medium containing either vehicle or ,-cryptoxanthin (10,8 to 10,6 M) without FBS. Cells were cultured for 3 to 21 days. Gene expression in osteoblastic cells was determined using reverse transcription-polymerase chain reaction (RT-PCR). Culture with ,-cryptoxanthin (10,7 or 10,6 M) for 3 days caused a significant increase in Runx2 type 1, Runx2 type 2, ,1 (I) collagen, and alkaline phosphatase mRNA levels in osteoblastic cells. These increases were completely blocked in the presence of cycloheximide, an inhibitor of protein synthesis, or 5,6-dichloro-1-,- D -ribofuranosylbenzimidazole (DRB), an inhibitor of transcriptional activity. Meanwhile, vitamin A (10,6 M) did not have a significant effect on Runx2 type 1 mRNA expression in the cells. The effect of ,-cryptoxanthin (10,6 M) in stimulating Runx2 type 1 and ,1 (I) collagen mRNA levels, protein content, and alkaline phosphatase activity in the cells was also seen in the presence of vitamin A (10,6 M), suggesting that the mode of ,-cryptoxanthin action differs from that of vitamin A. Prolonged culture with ,-cryptoxanthin (10,6 M) for 3 to 21 days caused a significant increase in cell number, deoxyribonucleic acid (DNA) content, protein content, and alkaline phosphatase activity in osteoblastic cells, suggesting that ,-cryptoxanthin stimulates cell proliferation and differentiation. Moreover, culture with ,-cryptoxanthin (10,7 or 10,6 M) for 5 to 21 days caused a remarkable increase in mineralization. This study demonstrates that ,-cryptoxanthin has a stimulatory effect on cell differentiation and mineralization due to enhancing gene expression of proteins, which involve in bone formation in osteoblastic MC3T3-E1 cells. © 2005 Wiley-Liss, Inc. [source] Moult speed constrains the expression of a carotenoid-based sexual ornamentJOURNAL OF EVOLUTIONARY BIOLOGY, Issue 5 2007L. SERRA Abstract We investigated the effect of moult speed on the expression of a sexually selected, carotenoid-based feather ornament in the rock sparrow (Petronia petronia). We experimentally accelerated the moult speed of a group of birds by exposing them to a rapidly decreasing photoperiod and compared the area and the spectral characteristics of their ornaments with those of control birds. Birds with accelerated moulting rate showed a smaller yellow patch with lower yellow reflectance compared to their slow-moulting counterparts. Considering that the time available for moulting is usually constrained between the end of the breeding season and migration or wintering, carotenoid feather ornaments, whose expression is mediated by moult speed, may convey long term information about an individual's condition, potentially encompassing the previous breeding season. Furthermore, the observed trade-off between moult speed and ornament expression may represent a previously unrecognized selective advantage for early breeding birds. [source] Carotenoid and protein supplementation have differential effects on pheasant ornamentation and immunityJOURNAL OF EVOLUTIONARY BIOLOGY, Issue 1 2007H. G. SMITH Abstract A currently popular hypothesis states that the expression of carotenoid-dependent sexual ornaments and immune function may be correlated because both traits are positively affected by carotenoids. However, such a correlation may arise for another reason: it is well known that immune function is dependent on nutritional condition. A recent study has suggested that the expression of ornaments may too depend on nutritional condition, as males in good nutritional condition are better at assimilating and/or modulating carotenoids. Thus, carotenoid-dependent ornaments and immune function may be correlated because both are dependent on nutritional condition. To elucidate if, and how, ornamentation and immune function are linked, pheasant diets were supplemented with carotenoid and/or protein in a fully factorial experiment. Carotenoid treatment affected wattle coloration and tail growth, but not cellular or humoral immunity. Immunity was unrelated to males' initial ornamentation including wattle colour. Males in better body condition, measured as residual mass, increased their wattle coloration more when carotenoid supplemented. Protein positively affected humoral but not cellular immunity, but had no effect on ornaments. Cellular, but not humoral, immunity increased with male body condition. Thus, there was no evidence that an immune-stimulatory effect of carotenoids resulted in wattle coloration honestly signalling immune function, but wattle coloration may still signal male body condition. [source] | ||||||||||||||||||||||||||||||||||||||||