Integument coloration signals reproductive success,heterozygosity, and antioxidant levels in chick-rearing black-legged kittiwakes

Carotenoid pigments are important for immunity and as antioxidants, and carotenoid-based colors are believed to provide honest signals of individual quality. Other colorless but more efficient antioxidants such as vitamins A and E may protect carotenoids from bleaching. Carotenoid-based colors have thus recently been suggested to reflect the concentration of such colorless antioxidants, but this has rarely been tested. Furthermore, although evidence is accruing for multiple genetic criteria for mate choice, carotenoid-based colors have rarely been shown to reflect both phenotypic and genetic quality. In this study, we investigated whether gape, tongue, eye-ring, and bill coloration of chick-rearing black-legged kittiwakes Rissa tridactyla reflected circulating levels of carotenoids and vitamins A and E. We further investigated whether integument coloration reflected phenotypic (body condition and fledging success) and genetic quality (heterozygosity). We found that the coloration of fleshy integuments was correlated with carotenoid and vitamin A levels and fledging success but only in males. Furthermore, the coloration of tongue and eye-ring was correlated with heterozygosity in both males and females. Integument colors might therefore be reliable signals of individual quality used by birds to adjust their parental care during the chick-rearing period.     

The liver but not the skin is the site for conversion of a red carotenoid in a passerine bird

Carotenoids may provide numerous health benefits and are also responsible for the integumentary coloration of many bird species. Despite their importance, many aspects of their metabolism are still poorly known, and even basic issues such as the anatomical sites of conversion remain controversial. Recent studies suggest that the transformation of carotenoid pigments takes place directly in the follicles during feather growth, even though the liver has been previously recognised as a storing organ for these pigments with a certain potential for conversion. In this context, we analysed the carotenoid profile of plasma, liver, skin and feathers of male Common Crossbills (Loxia curvirostra). Interestingly, the derivative feather pigment 3-hydroxy-echinenone was detected in the liver and in the bloodstream (i.e. the necessary vehicle to transport metabolites to colourful peripheral tissues). Our results demonstrate for the first time with empirical data that the liver may act as the main site for the synthesis of integumentary carotenoids. This finding contradicts previous assumptions and raises the question of possible inter-specific differences in the site of carotenoid conversion in birds.     

Polymorphic ROS scavenging revealed by CCCP in a lizard

Ingestion of antioxidants has been argued to scavenge circulating reactive molecules (e.g., free radicals), play a part in mate choice (by mediating access to this important resource), and perhaps increase life span. However, recent work has come to question these relationships. We have shown elsewhere in the polychromatic lizard, Ctenophorus pictus, that diet supplementation of carotenoids as antioxidants does not depress circulating natural reactive oxygen species (ROS) levels and leads to no corresponding improvement of color traits. However, a much stronger test would be to experimentally manipulate the ROS levels themselves and assess carotenoid-induced ROS depression. Here, we achieve this by using carbonyl cyanide 3-chlorophenylhydrazone, which elevates superoxide (SO) formation approximately threefold at 10 μM in this model system. We then look for depressing effects on ROS of the carotenoids in order to assess whether ‘super-production’ of SO makes carotenoid effects on elevated ROS levels detectable. The rationale for this treatment was that if not even such elevated levels of SO are reduced by carotenoid supplementation, the putative link carotenoids, ROS depression, and mate quality (in terms of antioxidant capacity) is highly questionable. We conclude that there is no significant effect of carotenoids on mean SO levels even at the induced ROS levels. However, our results showed a significant interaction effect between carotenoid treatment and male color, with red males having higher ROS levels than yellow males. We suggest that this may be because different pigments are differently involved in the generation of the integumental colors in the two morphs with concomitant effects on ROS depletion depending on carotenoid uptake or allocation to coloration and antioxidation.     

Maternally derived carotenoid pigments affect offspring survival, sex ratio, and sexual attractiveness in a colorful songbird

In egg-laying animals, mothers can influence the development of their offspring via the suite of biochemicals they incorporate into the nourishing yolk (e.g. lipids, hormones). However, the long-lasting fitness consequences of this early nutritional environment have often proved elusive. Here, we show that the colorful carotenoid pigments that female zebra finches (Taeniopygia guttata) deposit into egg yolks influence embryonic and nestling survival, the sex ratio of fledged offspring, and the eventual ornamental coloration displayed by their offspring as adults. Mothers experimentally supplemented with dietary carotenoids prior to egg-laying incorporated more carotenoids into eggs, which, due to the antioxidant activity of carotenoids, rendered their embryos less susceptible to free-radical attack during development. These eggs were subsequently more likely to hatch, fledge offspring, produce more sons than daughters, and produce sons who exhibited more brightly colored carotenoid-based beak pigmentation. Provisioned mothers also acquired more colorful beaks, which directly predicted levels of carotenoids found in eggs, thus indicating that these pigments may function not only as physiological ‘damage-protectants’ in adults and offspring but also as morphological signals of maternal reproductive capabilities.     

Astaxanthin and papilioerythrinone in the skin of birds: a chromatic convergence of two metabolic routes with different precursors?

Carotenoids are organic pigments involved in several important physiological functions and may serve as indicators of individual quality in animals. These pigments are only obtained by animals from the diet, but they can be later transformed into other carotenoids by specific enzymatic reactions. The diet of farm-reared and probably wild red-legged partridges (Alectoris rufa) is mainly based on cereals that contain high levels of lutein and zeaxanthin. These two carotenoids are also predominant in internal tissues and blood of red-legged partridges. However, in their integuments, astaxanthin and papilioerythrinone (the last one identified in this work) are mainly present in their free form and esterified with fatty acids. According to available literature about carotenoid metabolism in animals, we propose that astaxanthin (λ _max?=?478 nm) and papilioerythrinone (λ _max?=?452–478 nm) are the result of a chromatic convergence of the transformation of dietary zeaxanthin and lutein, respectively. Moreover, the results obtained in this work provide the first identification by liquid chromatography coupled to accurate mass quadrupole time-of-flight mass spectrometer system of papilioerythrinone (m/z 581.3989 [M?+?H]⁺) in the skin (i.e., not feathers) of a vertebrate. Astaxanthin and papilioerythrinone are very close in terms of chemical structure and coloration, and the combination of these two keto-carotenoids is responsible for the red color of the ornaments in red-legged partridges.     

Dietary antioxidants, lipid peroxidation and plumage colouration in nestling blue tits Cyanistes caeruleus

Carotenoid pigments are responsible for many of the red, yellow and orange plumage and integument traits seen in birds. One idea suggests that since carotenoids can act as antioxidants, carotenoid-mediated colouration may reveal an individual's ability to resist oxidative damage. In fact, there is currently very little information on the effects of most dietary-acquired antioxidants on oxidative stress in wild birds. Here, we assessed the impacts on oxidative damage, plasma antioxidants, growth and plumage colouration after supplementing nestling blue tits Cyanistes caeruleus with one of three diets; control, carotenoid treatment or α-tocopherol treatment. Oxidative damage was assessed by HPLC analysis of plasma levels of malondialdehyde (MDA), a by-product of lipid peroxidation. Contrary to predictions, we found no differences in oxidative damage, plumage colouration or growth rate between treatment groups. Although plasma lutein concentrations were significantly raised in carotenoid-fed chicks, α-tocopherol treatment had no effect on concentrations of plasma α-tocopherol compared with controls. Interestingly, we found that faster growing chicks had higher levels of oxidative damage than slower growing birds, independent of treatment, body mass and condition at fledging. Moreover, the chromatic signal of the chest plumage of birds was positively correlated with levels of MDA but not plasma antioxidant concentrations: more colourful nestlings had higher oxidative damage than less colourful individuals. Thus, increased carotenoid-mediated plumage does not reveal resistance to oxidative damage for nestling blue tits, but may indicate costs paid, in terms of oxidative damage. Our results indicate that the trade-offs between competing physiological systems for dietary antioxidants are likely to be complex in rapidly developing birds. Moreover, interpreting the biological relevance of different biomarkers of antioxidant status represents a challenge for evolutionary ecology.     

Carotenoid coloration is related to fat digestion efficiency in a wild bird

Some of the most spectacular visual signals found in the animal kingdom are based on dietarily derived carotenoid pigments (which cannot be produced de novo), with a general assumption that carotenoids are limited resources for wild organisms, causing trade-offs in allocation of carotenoids to different physiological functions and ornamentation. This resource trade-off view has been recently questioned, since the efficiency of carotenoid processing may relax the trade-off between allocation toward condition or ornamentation. This hypothesis has so far received little exploratory support, since studies of digestive efficiency of wild animals are limited due to methodological difficulties. Recently, a method for quantifying the percentage of fat in fecal samples to measure digestive efficiency has been developed in birds. Here, we use this method to test if the intensity of the carotenoid-based coloration predicts digestive efficiency in a wild bird, the house finch (Haemorhous mexicanus). The redness of carotenoid feather coloration (hue) positively predicted digestion efficiency, with redder birds being more efficient at absorbing fats from seeds. We show for the first time in a wild species that digestive efficiency predicts ornamental coloration. Though not conclusive due to the correlative nature of our study, these results strongly suggest that fat extraction might be a crucial but overlooked process behind many ornamental traits.     

外源一氧化氮对亚心形扁藻的生长效应及光谱研究

对海洋绿藻亚心形扁藻(Platymonas subcordiformis)分别进行了不同一氧化氮(NO)浓度和光照强度的培养实验,并进行了叶绿素a和类胡萝卜素含量测定,及室温吸收光谱和荧光光谱测定.结果表明,不同NO浓度、不同加入方式对亚心形扁藻生长有明显不同的促进或抑制作用,NO对亚心形扁藻生长的影响存在阈值.不同浓度NO在不同光照下对微藻生长的作用是一致的,外源NO可以弥补弱光照对藻生长的限制.NO对亚心形扁藻光合色素含量的影响和对藻密度的影响是一致的.NO对藻细胞中叶绿素复合蛋白组成没有显著影响,但对色素含量及其相对组成会产生一系列影响.NO能使藻细胞激发能的传递效率提高,从而提高光合作用速率,表现为细胞生长加快,藻细胞生物量增加.     

Carotenoids,immune response and the expression of sexual ornaments in male greenfinches (<Emphasis Type="Italic">Carduelis chloris</Emphasis>)

Allocation trade-offs of carotenoids between their use in the immune system and production of sexual ornaments have been suggested as a proximate mechanism maintaining honesty of sexual signals. To test this idea, we experimentally examined whether carotenoid availability in the diet was related to variation in antibody response to novel antigens in male greenfinches (Carduelis chloris aurantiiventris), a species with extensive carotenoid-dependent plumage colouration. We also measured the cost of mounting a humoral response in terms of circulating carotenoids. Finally, we examined the relationship between plumage colour, immune response and circulating carotenoids. We found that males with carotenoid-supplemented diets showed stronger antibody response than non-supplemented birds. We also found that activation of the immune system significantly reduced circulating carotenoids (24.9% lower in immune-challenged birds than in control birds). Finally, intensity (chroma) of ventral plumage colouration of males, a character directly related to concentration of total carotenoids in feathers, was negatively correlated with the immune response and circulating carotenoids in winter. These results support the idea that carotenoids are a limiting resource and that males trade ornamental colouration against immune response.     

Effect of cadmium on photosynthetic pigments, lipid peroxidation, antioxidants, and artemisinin in hydroponically grown Artemisia annua

The effects of different cadmium (Cd) concentrations (0, 20, 60, and 100 μmol/L) on hydroponically grown Artemisia annua L. were investigated. Cd treatments applied for 0, 4, 12, 24, 72, 144, 216, and 336 hr were assessed by measuring the changes in photosynthetic pigments, electrolyte leakage, malondialdehyde (MDA) and antioxidants (ascorbic acid and glutathione), while the artemisinin content was tested after 0, 12, 144, 216, and 336 hr. A significant decrease was observed in photosynthetic pigment levels over time with increasing Cd concentration. Chlorophyll b levels were more affected by Cd than were chlorophyll a or carotenoid levels. The cell membrane was sensitive to Cd stress, as MDA content in all treatment groups showed insignificant differences from the control group, except at 12 hr treatment time. Ascorbic acid (AsA) content changed slightly over time, while glutathione (GSH) content took less time to reach a maximum as Cd concentration increased. Cd was found to promote synthesis and accumulation of artemisinin, especially at concentrations of 20 and 100 μmol/L. In conclusion, Cd stress can damage to photosynthetic pigments, and vigorously growing A. annua showed a strong tolerance for Cd stress. Appropriate amounts of added Cd aided synthesis and accumulation of artemisinin.     

长江口-浙闽沿岸沉积色素的分布特征及其指示意义

利用高效液相色谱法分析了长江口-浙闽沿岸表层沉积物中的色素组成和含量,探讨了海洋初级生产力、浮游植物功能类群和浮游植物色素保存效率的空间分布特征及其影响因素.结果表明,沉积物中的色素类型主要为沉积绿素(chloropigments,Chlorins)[包括叶绿素a(chlorophyll-a,Chl-a)及其降解产物(pheopigments,Pheo-a),如脱镁叶绿素a(pheophytin-a,PHtin-a)、脱镁叶绿酸a(pheophorbide-a,PHide-a)、焦脱镁叶绿素a(p Pheophytin-a,p PHtin-a)、甾醇绿素酯(sterol chlorin esters,SCEs)和胡萝卜醇绿素酯(carotenol chlorin esters,CCEs)].Chlorins高值区呈南北两大斑块状分布,可能主要是受到长江冲淡水及浙闽沿岸泥质区上升流输运的营养盐的影响.研究区域内类胡萝卜素整体上无明显趋势性变化,在长江口以及浙闽沿岸各呈现一个高值区.基于沉积物中特征类胡萝卜素比例估算得到的浮游植物功能类群中硅藻、甲藻、定鞭藻、青绿藻、隐藻和蓝藻的相对贡献分别为48.8%±17.4%、10.7%±11.5%、8.1%±7.2%、18.6%±8.2%、9.4%±6.4%和4.3%±3.2%.对营养盐水平、水体盐度等外界环境的偏好导致硅藻和甲藻比例离岸降低,青绿藻、隐藻和蓝藻比例离岸增加.Chl-a/Pheo-a比值的分布表明,较高的沉积速率以及季节性的底层水体缺氧事件导致了近岸海域(长江口最大浑浊带外缘、杭州湾湾口以及浙闽沿岸上升流区)具有较高的沉积色素保存效率,这些沉积色素保存效率较高的区域可能是进行海洋生态环境历史重建的理想区域,而杭州湾水体通过舟山群岛与外部海水进行水体交换时造成的较差沉积环境可能是导致杭州湾外海具有较低沉积色素含量和较低保存效率的主要原因.     

Carotenoid-based bill and eye ring coloration as honest signals of condition: an experimental test in the red-legged partridge (<Emphasis Type="Italic">Alectoris rufa</Emphasis>)

Carotenoid pigments cannot be synthesized by vertebrates but must be ingested through the diet. As they seem to be a limited resource, carotenoid-based ornaments are particularly interesting as possible honest signals of individual quality, in particular of foraging efficiency and nutritional status. Some studies have demonstrated the condition dependence of carotenoid-based plumage in birds. However, many other carotenoid-pigmented bare parts (i.e. skin, caruncles, bills, cere, and tarsi) are present in birds but, in comparison with plumage, little is known about these traits as indicators of individual quality. Here, we show that the eye ring pigmentation and bill redness of the red-legged partridge (Alectoris rufa) are positively associated to body condition and recent changes in body mass. Also, we found a negative relationship between these two traits and heterophil-to-lymphocyte ratio, an indicator of physiological stress (the relationship with bill redness being significant only for males). In an experiment, we found that after a period of reduction in food intake (with the consequent loss of body mass), food-restricted birds showed lower eye ring pigmentation than ad-libitum-fed birds. Therefore, different ornaments seem to reflect changes in body condition but at different speeds or intensities (eye ring, a fleshy ornament, appears to respond more rapidly to changes in the nutritional status than a keratinized structure as the bill). These results indicate that carotenoid-based ornaments are condition-dependent traits in the red-legged partridge, being therefore susceptible to be employed as honest signals of quality in sexual selection.     

Carotenoid-based bill colour is an integrative signal of multiple parasite infection in blackbird

In the study of parasite-mediated sexual selection, there has been controversial evidence for the prediction that brighter males should have fewer parasites. Most of these studies have focused on one parasite species. Our aim was to investigate the expression of carotenoid-based coloured signals in relation to patterns of multiple parasite infections, to determine whether colour reflects parasite load of all parasite species, or whether different relationships might be found when looking at each parasite species independently. We investigated the relationship between bill colour, body mass and plasma carotenoids and parasite load (feather chewing lice, blood parasite Plasmodium sp., intestinal parasites cestodes and coccidia) in the blackbird (Turdus merula). Bill colour on its own appeared to be a poor predictor of parasite load when investigating its relationships with individual parasite species. Variation in parasite intensities at the community level was summarised using principal component analysis to derive synthetic indexes of relative parasite species abundance and absolute parasite load. The relative abundance of parasite species was strongly related to bill colour, plasma carotenoid levels and body mass: birds with relatively more cestodes and chewing lice and relatively less Plasmodium and coccidia had a more colourful bill, circulated more carotenoids and were heavier. These results suggest that bill colour more accurately reflects the relative intensities of parasite infection, rather than one-by-one relationships with parasites or absolute parasite burden. Investigating patterns of multiple parasite infection would thus improve our understanding of the information conveyed by coloured signals on parasite load.     

Carotenoid maintenance handicap and the physiology of carotenoid-based signalisation of health

Despite a reasonable scientific interest in sexual selection, the general principles of health signalisation via ornamental traits remain still unresolved in many aspects. This is also true for the mechanism preserving honesty of carotenoid-based signals. Although it is widely accepted that this type of ornamentation reflects an allocation trade-off between the physiological utilisation of carotenoids (mainly in antioxidative processes) and their deposition in ornaments, some recent evidence suggests more complex interactions. Here, we further develop the models currently proposed to explain the honesty of carotenoid-based signalisation of heath status by adding the handicap principle concept regulated by testosterone. We propose that under certain circumstances carotenoids may be dangerous for the organism because they easily transform into toxic cleavage products. When reserves of other protective antioxidants are insufficient, physiological trade-offs may exist between maintenance of carotenoids for ornament expression and their removal from the body. Furthermore, we suggest that testosterone which enhances ornamentation by increasing carotenoid bioavailability may also promote oxidative stress and hence lower antioxidant reserves. The presence of high levels of carotenoids required for high-quality ornament expression may therefore represent a handicap and only individuals in prime health could afford to produce elaborate colourful ornaments. Although further testing is needed, this ‘carotenoid maintenance handicap’ hypothesis may offer a new insight into the physiological aspects of the relationship between carotenoid function, immunity and ornamentation.     

紫外可见分光光度法测定湖泊沉积物中的色素

对新疆博斯腾湖沉积物柱样中叶绿素、胡萝卜素、颤藻黄素和蓝藻黄素等几种色素进行了提取并用紫外可见分光光度法进行测定 ,计算了沉积物中几种色素的含量。沉积物中色素指标的分析 ,可以帮助揭示博斯腾湖的环境、历史气候变化等特征     

Plumage coloration and nutritional condition in the great tit<Emphasis Type="Italic"> Parus major</Emphasis>: the roles of carotenoids and melanins differ

The size and coloration of some body characters seem to influence mate choice in many species. Most animal colours are either structural or based on melanin or carotenoid pigments. It has recently been suggested that carotenoid-based or structural coloration may be a condition-dependent trait, whereas melanin-based coloration is not; a difference that may be highly relevant when studying the evolution of multiple mating preferences. We tested this hypothesis in the great tit (Parus major). The size of the melanin breast band was not correlated to nutritional condition as estimated by the rate of tail growth (ptilochronology), controlling for locality, age, sex, year and season effects. However, the correlation was significant for the hue of yellow breast (carotenoid-based coloration), and the slopes of the regressions of the two pigments to growth bars differed significantly. These results suggest that the expression of the two traits may be regulated by different mechanisms.     

Mutations of mitochondrial DNA and human death

In the skeletal muscle of patients with mitochondrial myopathies (Kearns-Sayre syndrome and chronic progressive external ophthalmoplegia) and in the heart and skeletal muscle of healthy persons cells lacking cytochrome c oxidase are found. The respiratory-defective cells have the following features in common: onset of the defect at juvenile or adult age; progressive character of the defect with increasing age; and focal pattern of respiratory-deficient cells (fibers). A statistic mutation of mtDNA in affected cells is suggested to cause the defect of mitochondrial function. It is postulated that the continuous accumulation of respiratory-deficient cells, mainly in the human heart with increasing age, will finally limit the life-span of each human individual.     

Assortative mating by carotenoid-based plumage colour: a quality indicator in American goldfinches,<Emphasis Type="Italic"> Carduelis tristis</Emphasis>

We investigated the mating patterns in 22 breeding pairs of wild American goldfinches (Carduelis tristis) with respect to their body size, condition, and carotenoid-based, yellow plumage colour. Using reflectance spectrometry, we objectively quantified plumage colours across the bird-visible wavelengths, revealing a unexpected UV peak in the reflectance spectrum from yellow feathers. We summarized our colour measurements using a principal components analysis to create a single variable, carotenoid PC1, that represents the intensity of this carotenoid-based yellow colour, a measure of phenotypic quality in this species. We found no evidence of assortative mating with respect to measures of body size or condition but there was positive assortative mating by carotenoid PC1, such that the yellow plumage colours of males and females were significantly correlated within pairs. We argue that the yellow carotenoid coloration of goldfinches may be important in mutual mate choice and, thus, that sexual selection in this species may act upon female ornamentation, as well as the more obvious plumage signals of males. Because assortative mating results in an increase in genetic variance, we suggest that this might be a mechanism that maintains variance in ornamental traits in spite of the variance-eroding effects of sexual selection.     

城市大气环境下绿化植物叶片比叶重和光合色素含量

研究了大叶女贞(Ligustrum lucidum Ait.)和小叶女贞(Ligustrum quihoui Carr.)在不同大气环境条件下叶片中Pb、Cd、叶绿素a (Chl a)、叶绿素b(Chl b)、类胡萝卜素(Car)的含量及比叶重(LMA),分析了因素之间的相互关系.不同环境条件下叶片中Pb、Cd、Chl a、Chl b、Chl (a+b)、Car的含量及LMA具有显著差异.随污染程度的加剧,叶片中Pb、Cd的含量、LMA和Chl a/Chl b升高,而Chl a、Chl b和Chl (a+b)含量则呈现相反的变化趋势.大叶女贞叶片中Car含量变化不明显,而小叶女贞叶片中Car含量在污染严重的采样点明显较其他采样点高.2种植物叶片中Pb、Cd的含量对叶片LMA和光合色素含量均具有明显影响,Chl a、Chl b及Chl (a+b)含量与叶片中Pb、Cd的含量呈显著负相关(P<0.05).叶片中Cd含量的增大导致Car含量增大,而Pb的作用与物种有关.叶片中Pb含量的增大导致2物种LMA增大,而Cd含量导致大叶女贞LMA增大而小叶女贞LMA变化不明显.污染胁迫下植物叶片会增大LMA、Chl a/Chl b,减小Chl a、Chl b和Chl (a+b)含量,据此可对大气污染进行生物监测.     

Polychlorinated dibenzo-p-dioxins and dibenzofurans in different tissues of the cormorants (Phalacrocorax carbo) from Dongting Lake, China

Tissue distribution provides important information regarding the pharmacokinetic behavior of pollutants and is invaluable when analyzing the risk posed to avian species by the exposure to such kind of pollutants. In this study, concentrations of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) were determined in muscle, liver, spleen, kidney, stomach, gall bladder, skin, heart, pancreas, intestine and lung tissue extracts of cormorants collected from Dongting Lake, China. Tissue distribution results showed preferential accumulation of PCDD/Fs in both liver and skin. The total concentration of PCDD/Fs ranged from 421 to 5696 pg/g lipid weight. Octachlorinated dibenzo-p-dioxin (OCDD) was the predominant congener in all tissues and contributed between 31% and 82% to all 17 PCDD/Fs in different tissues. The liver/muscle ratios progressively increased with the degree of chlorination of PCDDs, except for OCDD. The relative toxic potential of PCDDs and PCDFs in tissues were calculated using the World Health Organization (WHO) Toxic Equivalency Factors (TEFs) for birds. The concentrations of WHO-toxic equivalent in different tissues ranged between 14.8 and 2021 pg/g lipid weight. These results indicated PCDD/Fs may have been bio-accumulated in cormorant via food-web. Furthermore, when compared with studies reported in the literatures, the PCDD/Fs levels in the cormorant collected from Dongting Lake were still relatively high.