RESUMO
We recently reported that the accumulation of myeloid-derived suppressor cells (MDSC), defined as CD33+HLA-DR-Lin-, has a direct role in the pathogenesis of myelodysplastic syndrome (MDS). In particular, CD33 is strongly expressed in MDSC isolated from patients with MDS where it has an important role in MDSC-mediated hematopoietic suppressive function through its activation by S100A9. Therefore, we tested whether blocking this interaction with a fully human, Fc-engineered monoclonal antibody against CD33 (BI 836858) suppresses CD33-mediated signal transduction and improves the bone marrow microenvironment in MDS. We observed that BI 836858 can reduce MDSC by antibody-dependent cellular cytotoxicity, which correlated with increases in granule mobilization and cell death. BI 836858 can also block CD33 downstream signaling preventing immune-suppressive cytokine secretion, which correlates with a significant increase in the formation of CFU-GM and BFU-E colonies. Activation of the CD33 pathway can cause reactive oxygen species (ROS)-induced genomic instability but BI 836858 reduced both ROS and the levels of double strand breaks and adducts (measured by comet assay and γH2AX). This work provides the ground for the development of a novel group of therapies for MDS aimed at MDSC and their disease-promoting properties with the goal of improving hematopoiesis in patients.
Assuntos
Anticorpos Monoclonais/uso terapêutico , Hematopoese/efeitos dos fármacos , Fragmentos Fc das Imunoglobulinas/uso terapêutico , Terapia de Alvo Molecular , Síndromes Mielodisplásicas/terapia , Células Supressoras Mieloides/efeitos dos fármacos , Lectina 3 Semelhante a Ig de Ligação ao Ácido Siálico/imunologia , Idoso , Idoso de 80 Anos ou mais , Anticorpos Monoclonais Humanizados , Citotoxicidade Celular Dependente de Anticorpos , Medula Óssea/patologia , Feminino , Engenharia Genética , Instabilidade Genômica , Humanos , Masculino , Pessoa de Meia-Idade , Síndromes Mielodisplásicas/sangue , Síndromes Mielodisplásicas/imunologia , Síndromes Mielodisplásicas/patologia , Células Supressoras Mieloides/imunologia , Espécies Reativas de Oxigênio , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/imunologia , Nicho de Células-TroncoAssuntos
Fatores Imunológicos/uso terapêutico , Síndromes Mielodisplásicas/tratamento farmacológico , Talidomida/análogos & derivados , Adulto , Idoso , Idoso de 80 Anos ou mais , Cromossomos Humanos Par 5 , Estudos de Coortes , Feminino , Humanos , Lenalidomida , Masculino , Pessoa de Meia-Idade , Mutação , Síndromes Mielodisplásicas/genética , Talidomida/uso terapêutico , Adulto JovemAssuntos
Mutação , Síndromes Mielodisplásicas/genética , Subunidade alfa 2 de Fator de Ligação ao Core/genética , Progressão da Doença , GTP Fosfo-Hidrolases/genética , Genes p53 , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Proteínas de Membrana/genética , Proteínas Nucleares/genética , Proteínas Repressoras/genética , Ribonucleoproteínas/genéticaRESUMO
Although next-generation sequencing has allowed for the detection of somatic mutations in myelodysplastic syndromes (MDS), the clinical relevance of variant allele frequency (VAF) for the majority of mutations is unknown. We profiled TP53 and 20 additional genes in our training set of 219 patients with MDS or secondary acute myeloid leukemia with findings confirmed in a validation cohort. When parsed by VAF, TP53 VAF predicted for complex cytogenetics in both the training (P=0.001) and validation set (P<0.0001). MDS patients with a TP53 VAF > 40% had a median overall survival (OS) of 124 days versus an OS that was not reached in patients with VAF <20% (hazard ratio (HR), 3.52; P=0.01) with validation in an independent cohort (HR, 4.94, P=0.01). TP53 VAF further stratified distinct prognostic groups independent of clinical prognostic scoring systems (P=0.0005). In multivariate analysis, only a TP53 VAF >40% was an independent covariate (HR, 1.61; P<0.0001). In addition, SRSF2 VAF predicted for monocytosis (P=0.003), RUNX1 VAF with thrombocytopenia (P=0.01) and SF3B1 with ringed sideroblasts (P=0.001). Together, our study indicates that VAF should be incorporated in patient management and risk stratification in MDS.
Assuntos
Frequência do Gene , Leucemia Mieloide Aguda/diagnóstico , Mutação , Síndromes Mielodisplásicas/diagnóstico , Fenótipo , Proteína Supressora de Tumor p53/genética , Idoso , Idoso de 80 Anos ou mais , Alelos , Subunidade alfa 2 de Fator de Ligação ao Core/genética , Análise Citogenética , Feminino , Seguimentos , Expressão Gênica , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Leucemia Mieloide Aguda/genética , Leucemia Mieloide Aguda/mortalidade , Leucemia Mieloide Aguda/patologia , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Síndromes Mielodisplásicas/genética , Síndromes Mielodisplásicas/mortalidade , Síndromes Mielodisplásicas/patologia , Proteínas Nucleares/genética , Fosfoproteínas/genética , Prognóstico , Fatores de Processamento de RNA , Ribonucleoproteína Nuclear Pequena U2/genética , Ribonucleoproteínas/genética , Fatores de Processamento de Serina-Arginina , Análise de SobrevidaRESUMO
Nonsynonymous TP53 exon 4 single-nucleotide polymorphism (SNP), R72P, is linked to cancer and mutagen susceptibility. R72P associations with specific cancer risk, particularly hematological malignancies, have been conflicting. Myelodysplastic syndrome (MDS) with chromosome 5q deletion is characterized by erythroid hypoplasia arising from lineage-specific p53 accumulation resulting from ribosomal insufficiency. We hypothesized that apoptotically diminished R72P C-allele may influence predisposition to del(5q) MDS. Bone marrow and blood DNA was sequenced from 705 MDS cases (333 del(5q), 372 non-del(5q)) and 157 controls. Genotype distribution did not significantly differ between del(5q) cases (12.6% CC, 38.1% CG, 49.2% GG), non-del(5q) cases (9.7% CC, 44.6% CG, 45.7% GG) and controls (7.6% CC, 37.6% CG, 54.8% GG) (P=0.13). Allele frequency did not differ between non-del(5q) and del(5q) cases (P=0.91) but trended towards increased C-allele frequency comparing non-del(5q) (P=0.08) and del(5q) (P=0.10) cases with controls. Median lenalidomide response duration increased proportionate to C-allele dosage in del(5q) patients (2.2 (CC), 1.3 (CG) and 0.89 years (GG)). Furthermore, C-allele homozygosity in del(5q) was associated with prolonged overall and progression-free survival and non-terminal interstitial deletions that excluded 5q34, whereas G-allele homozygozity was associated with inferior outcome and terminal deletions involving 5q34 (P=0.05). These findings comprise the largest MDS R72P SNP analysis.
Assuntos
Deleção Cromossômica , Síndromes Mielodisplásicas/genética , Proteína Supressora de Tumor p53/genética , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Frequência do Gene , Humanos , Estimativa de Kaplan-Meier , Masculino , Pessoa de Meia-Idade , Mutação , Síndromes Mielodisplásicas/tratamento farmacológico , Síndromes Mielodisplásicas/patologia , Polimorfismo de Nucleotídeo Único , Resultado do TratamentoRESUMO
Allelic deletion of the RPS14 gene is a key effector of the hypoplastic anemia in patients with myelodysplastic syndrome (MDS) and chromosome 5q deletion (del(5q)). Disruption of ribosome integrity liberates free ribosomal proteins to bind to and trigger degradation of mouse double minute 2 protein (MDM2), with consequent p53 transactivation. Herein we show that p53 is overexpressed in erythroid precursors of primary bone marrow del(5q) MDS specimens accompanied by reduced cellular MDM2. More importantly, we show that lenalidomide (Len) acts to stabilize MDM2, thereby accelerating p53 degradation. Biochemical and molecular analyses showed that Len inhibits the haplodeficient protein phosphatase 2A catalytic domain alpha (PP2Acα) phosphatase resulting in hyperphosphorylation of inhibitory serine-166 and serine-186 residues on MDM2, and displaces binding of RPS14 to suppress MDM2 autoubiquitination whereas PP2Acα overexpression promotes drug resistance. Bone marrow specimens from del(5q) MDS patients resistant to Len overexpressed PP2Acα accompanied by restored accumulation of p53 in erythroid precursors. Our findings indicate that Len restores MDM2 functionality in the 5q- syndrome to overcome p53 activation in response to nucleolar stress, and therefore may warrant investigation in other disorders of ribosomal biogenesis.
Assuntos
Cromossomos Humanos Par 5 , Síndromes Mielodisplásicas/genética , Proteínas Proto-Oncogênicas c-mdm2/metabolismo , Talidomida/análogos & derivados , Proteína Supressora de Tumor p53/metabolismo , Animais , Deleção Cromossômica , Humanos , Lenalidomida , Camundongos , Talidomida/farmacologia , UbiquitinaçãoRESUMO
Telomeres are specialized structures providing chromosome integrity during cellular division along with protection against premature senescence and apoptosis. Accelerated telomere attrition in patients with myelodysplastic syndrome (MDS) occurs by an undefined mechanism. Although the MDS clone originates within the myeloid compartment, T-lymphocytes display repertoire contraction and loss of naive T-cells. The replicative lifespan of T-cells is stringently regulated by telomerase activity. In MDS cases, we show that purified CD3+ T-cells have significantly shorter telomere length and reduced proliferative capacity upon stimulation compared with controls. To understand the mechanism, telomerase enzymatic activity and telomerase reverse transcriptase (hTERT), gene expression were compared in MDS cases (n=35) and healthy controls (n=42) within different T-cell compartments. Telomerase activity is greatest in naive T-cells illustrating the importance of telomere repair in homeostatic repertoire regulation. Compared with healthy controls, MDS cases had lower telomerase induction (P<0.0001) that correlated with significantly lower hTERT mRNA (P<0.0001), independent of age and disease stratification. hTERT mRNA deficiency affected naive but not memory T-cells, and telomere erosion in MDS occurred without evidence of an hTERT-promoter mutation, copy number variation or deletion. Telomerase insufficiency may undermine homeostatic control within the hematopoietic compartment and promote a change in the T-cell repertoire in MDS.
Assuntos
Síndromes Mielodisplásicas/imunologia , Linfócitos T/imunologia , Telomerase/genética , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Bromodesoxiuridina , Estudos de Casos e Controles , Proliferação de Células , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Síndromes Mielodisplásicas/enzimologia , Síndromes Mielodisplásicas/genética , Telomerase/metabolismo , Telômero , Adulto JovemRESUMO
Carotenoid-based coloration has attracted much attention in evolutionary biology owing to its role in honest, condition-dependent signalling. Knowledge of the genetic pathways that regulate carotenoid coloration is crucial for an understanding of any trade-offs involved. We identified genes with potential roles in carotenoid coloration in vertebrates via (i) carotenoid uptake (SR-BI, CD36), (ii) binding and deposition (StAR1, MLN64, StAR4, StAR5, APOD, PLIN, GSTA2), and (iii) breakdown (BCO2, BCMO1). We examined the expression of these candidate loci in carotenoid-coloured tissues and several control tissues of the red-billed quelea (Quelea quelea), a species that exhibits a male breeding plumage colour polymorphism and sexually dimorphic variation in bill colour. All of the candidate genes except StAR1 were expressed in both the plumage and bill of queleas, indicating a potential role in carotenoid coloration in the quelea. However, no differences in the relative expression of any of the genes were found among the quelea carotenoid phenotypes, suggesting that other genes control the polymorphic and sexually dimorphic variation in carotenoid coloration observed in this species. Our identification of a number of potential carotenoid genes in different functional categories provides a critical starting point for future work on carotenoid colour regulation in vertebrate taxa.
Assuntos
Carotenoides/genética , Carotenoides/metabolismo , Pigmentação , Aves Canoras/genética , Animais , Bico/química , Bico/metabolismo , Carotenoides/análise , Galinhas/genética , Plumas/química , Plumas/metabolismo , Feminino , Estudos de Associação Genética/veterinária , Masculino , Especificidade de Órgãos , Polimorfismo Genético , Reação em Cadeia da Polimerase em Tempo Real/veterinária , Reação em Cadeia da Polimerase Via Transcriptase Reversa/veterinária , Alinhamento de Sequência/veterinária , Aves Canoras/metabolismo , África do Sul , ZimbábueRESUMO
The differential allocation hypothesis predicts that females modify their investment in a breeding attempt according to its reproductive value. One prediction of this hypothesis is that females will increase reproductive investment when mated to high-quality males. In birds, it was shown that females can modulate pre-hatch reproductive investment by manipulating egg and clutch sizes and/or the concentrations of egg internal compounds according to paternal attractiveness. However, the differential allocation of immune factors has seldom been considered, particularly with an experimental approach. The carotenoid-based ornaments can function as reliable signals of quality, indicating better immunity or ability to resist parasites. Thus, numerous studies show that females use the expression of carotenoid-based colour when choosing mates; but the influence of this paternal coloration on maternal investment decisions has seldom been considered and has only been experimentally studied with artificial manipulation of male coloration. Here, we used dietary carotenoid provisioning to manipulate male mallard (Anas platyrhynchos) bill coloration, a sexually selected trait, and followed female investment. We show that an increase of male bill coloration positively influenced egg mass and albumen lysozyme concentration. By contrast, yolk carotenoid concentration was not affected by paternal ornamentation. Maternal decisions highlighted in this study may influence chick survival and compel males to maintain carotenoid-based coloration from the mate-choice period until egg-laying has been finished.
Assuntos
Bico/fisiologia , Carotenoides , Patos/fisiologia , Preferência de Acasalamento Animal/fisiologia , Pigmentos Biológicos , Animais , Feminino , MasculinoRESUMO
Paternity in male animals can be influenced by their phenotypic signals of quality. Accordingly, the behavior underlying patterns of paternity should be flexible as signals of quality change. To evaluate the dynamics of paternity allocation, we analyzed paternity before and after manipulating plumage coloration, a known signal of quality, in male barn swallows Hirundo rustica. We found that, in successive breeding bouts, only males whose plumage color was experimentally enhanced received greater paternity from their social mates, demonstrating evidence for flexible and dynamic paternity allocation and the importance for males of maintaining signals of quality well after pair bond formation.
Assuntos
Plumas , Pigmentação , Comportamento Sexual Animal , Andorinhas/anatomia & histologia , Andorinhas/fisiologia , Animais , Cruzamento , Pai , Feminino , Masculino , Oviposição , Ligação do Par , Fenótipo , Estações do AnoRESUMO
Many birds use carotenoid pigments to acquire rich red, orange, and yellow coloration in feathers and bare parts that is used as a signal of mate quality. Because carotenoids are derived from foods, much attention has been paid to the role of diet in generating color variation both within and among avian species. Less consideration has been given to physiological underpinnings of color variability, especially among species. Here, I surveyed published literature (e.g. captive feeding studies) on carotenoid assimilation in six bird species and completed additional controlled carotenoid-supplementation experiments in two others to consider the ability of different taxa to extract carotenoids from the diet in relation to phylogeny and coloration. I found that, for a given level of carotenoids in the diet, passerine birds (zebra finch, Taeniopygia guttata; house finch, Carpodacus mexicanus; American goldfinch, Carduelis tristis; society finch, Lonchura domestica) exhibit higher levels of carotenoids in circulation than non-passerines like gamebirds (domestic chicken, Gallus domesticus; red junglefowl, Gallus gallus; Japanese quail, Coturnix coturnix; red-legged partridge, Alectoris rufa). This difference in carotenoid accumulation is likely due to interspecific variation in micelle, chylomicron, or lipoprotein concentrations or affinities for xanthophyll carotenoids. Passerine birds more commonly develop carotenoid-based colors than do birds from ancient avian lineages such as Galliformes, and the physiological differences I uncover may explain why songbirds especially capitalize on carotenoid pigments for color production. Ultimately, because we can deconstruct color traits into component biochemical, physical, and physiological parts, avian color signals may serve as a valuable model for illuminating the proximate mechanisms behind interspecific variation in signal use in animals.
Assuntos
Aves/genética , Carotenoides/farmacocinética , Dieta , Plumas/fisiologia , Filogenia , Pigmentação/fisiologia , Animais , Aves/metabolismo , Carotenoides/metabolismo , Variação Genética , Especificidade da EspécieRESUMO
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.
Assuntos
Carotenoides/fisiologia , Tentilhões/fisiologia , Comportamento Materno , Pigmentação/fisiologia , Comportamento Sexual Animal , Animais , Feminino , Masculino , Razão de MasculinidadeRESUMO
The estrildid finches (Aves: Passeriformes: Estrildidae) of Africa, Asia, and Australia have been the focus of several recent tests of sexual selection theory. Many estrildids display bright red, orange, or yellow colors in the beak or plumage, which typically are generated by the presence of carotenoid pigments. In this study, we used high-performance liquid chromatography to investigate the carotenoid content of feathers and other colorful tissues in seven species of estrildids. Star finches (Neochmia ruficauda) and diamond firetails (Stagonopleura guttata) circulated two main dietary carotenoids (lutein and zeaxanthin) through the blood and liver and used both to acquire a yellow plumage color. However, five other estrildids (common waxbill, Estrilda astrild; black-rumped waxbill, Estrilda troglodytes; zebra waxbill, Amandava subflava; red avadavat, Amandava amandava; and zebra finch, Taeniopygia guttata) circulated these same dietary carotenoids along with two metabolites (dehydrolutein and anhydrolutein) through the blood and/or liver and used all four as yellow plumage colorants. We subsequently tracked the distribution of these pigments using a published phylogeny of estrildid finches to determine the evolutionary pattern of carotenoid metabolism in these birds. We found that finches from the most ancient tribe of estrildids (Estrildini) possessed the ability to metabolize dietary carotenoids. Although carotenoids from the most ancestral extant estrildid species have yet to be analyzed, we hypothesize (based on their relationships with other songbirds known to have such metabolic capabilities) that these finches inherited from their ancestors the capability to metabolize carotenoids. Interestingly, later in estrildid evolution, certain taxa lost the ability to metabolize dietary carotenoids (e.g., in the Poephilini), suggesting that the occurrence of carotenoid metabolism can be labile and is likely shaped by the relative costs and benefits of color signaling across different species.
Assuntos
Evolução Biológica , Carotenoides/análise , Tentilhões/fisiologia , Pigmentação/fisiologia , Animais , Carotenoides/sangue , Plumas/química , Feminino , Tentilhões/classificação , Extratos Hepáticos/química , Masculino , Filogenia , Caracteres Sexuais , Especificidade da EspécieRESUMO
Carotenoid pigments are commonly used as colorants of feathers and bare parts by birds. However, parrots (Aves: Psittaciformes) use a novel class of plumage pigments (called psittacofulvins) that, like carotenoids, are lipid-soluble and red, orange, or yellow in color. To begin to understand how and why parrots use these pigments and not carotenoids in their feathers, we must first describe the distribution of these two types of pigments in the diet, tissues, and fluids of these birds. Here, we studied the carotenoid content of blood in five species of parrots with red in their plumage to see if they show the physiological ability to accumulate carotenoids in the body. Although Scarlet (Ara macao) and Greenwing Macaws (Ara chloroptera) and Eclectus (Eclectus roratus), African Gray (Psittacus erithacus) and Blue-fronted Amazon (Amazona aestiva) Parrots all use psittacofulvins to color their feathers red, we found that they also circulated high concentrations of both dietary (lutein, zeaxanthin, beta-cryptoxanthin) and metabolically derived (anhydrolutein, dehydrolutein) carotenoids through blood at the time of feather growth, at levels comparable to those found in many other carotenoid-colored birds. These results suggest that parrots have the potential to use carotenoids for plumage pigmentation, but preferentially avoid depositing them in feathers, which is likely under the control of the maturing feather follicle. As there is no evidence of psittacofulvins in parrot blood at the tune of feather growth, we presume that these pigments are locally synthesized by growing feathers within the follicular tissue.
Assuntos
Carotenoides/sangue , Plumas/metabolismo , Papagaios/fisiologia , Pigmentação/fisiologia , Pigmentos Biológicos/sangue , Animais , Plumas/anatomia & histologia , Feminino , Masculino , Papagaios/anatomia & histologia , Papagaios/classificação , Alcaloides de Pirrolizidina/química , Alcaloides de Pirrolizidina/metabolismoRESUMO
Many birds obtain colorful carotenoid pigments from the diet and deposit them into growing tissues to develop extravagant red, orange or yellow sexual ornaments. In these instances, it is often unclear whether all dietary pigments are used as integumentary colorants or whether certain carotenoids are preferentially excluded or incorporated into tissues. We examined the carotenoid profiles of three New World passerines that display yellow plumage coloration-the yellow warbler (Dendroica petechia), common yellowthroat (Geothlypis trichas) and evening grosbeak (Coccothraustes vespertinus). Using high-performance liquid chromatography, we found that all species used only one carotenoid-lutein-to color their plumage yellow. Analyses of blood carotenoids (which document those pigments taken up from the diet) in two of the species, however, revealed the presence of two dietary xanthophylls-lutein and zeaxanthin-that commonly co-occur in plants and animals. These findings demonstrate post-absorptive selectivity of carotenoid deposition in bird feathers. To learn more about the site of pigment discrimination, we also analyzed the carotenoid composition of lipid fractions from the follicles of immature yellow-pigmented feathers in G. trichas and D. petechia and again detected both lutein and zeaxanthin. This suggests that selective lutein incorporation in feathers is under local control at the maturing feather follicle.
Assuntos
Carotenoides/química , Plumas/metabolismo , Luteína/metabolismo , Pigmentação/fisiologia , Aves Canoras/fisiologia , Animais , Carotenoides/metabolismo , Cromatografia Líquida de Alta Pressão , Dieta , Plumas/anatomia & histologia , Feminino , Masculino , Aves Canoras/anatomia & histologiaRESUMO
Many birds acquire carotenoid pigments from the diet that they deposit into feathers and bare parts to develop extravagant sexual coloration. Although biologists have shown interest in both the mechanisms and function of these colorful displays, the carotenoids ingested and processed by these birds are poorly described. Here we document the carotenoid-pigment profile in the diet, blood and tissue of captive male and female zebra finches (Taeniopygia guttata). Dietary carotenoids including: lutein; zeaxanthin; and beta-cryptoxanthin were also present in the plasma, liver, adipose tissue and egg-yolk. These were accompanied in the blood and tissues by a fourth pigment, 2',3'-anhydrolutein, that was absent from the diet. To our knowledge, this is the first reported documentation of anhydrolutein in any avian species; among animals, it has been previously described only in human skin and serum and in fish liver. We also identified anhydrolutein in the plasma of two closely related estrildid finch species (Estrilda astrild and Sporaeginthus subflavus). Anhydrolutein was the major carotenoid found in zebra finch serum and liver, but did not exceed the concentration of lutein and zeaxanthin in adipose tissue or egg yolk. Whereas the percent composition of zeaxanthin and beta-cryptoxanthin were similar between diet and plasma, lutein was comparatively less abundant in plasma than in the diet. Lutein also was proportionally deficient in plasma from birds that circulated a higher percentage of anhydrolutein. These results suggest that zebra finches metabolically derive anhydrolutein from dietary sources of lutein. The production site and physiological function of anhydrolutein have yet to be determined.
Assuntos
Luteína/química , Luteína/metabolismo , Aves Canoras/fisiologia , Animais , Dieta , Feminino , Humanos , Masculino , Estrutura Molecular , Pigmentação , Plasma/química , Distribuição TecidualRESUMO
We investigated potential dietary and biochemical bases for carotenoid-based sexual dichromatism in American goldfinches (Carduelis tristis). Captive male and female finches were given access to the same type and amount of carotenoid pigments in the diet during their nuptial molt to assess differences in the degree to which the two sexes incorporated ingested pigments into their plumage. When birds were fed a uniform, plain-seed diet, or one that was supplemented with the red carotenoid canthaxanthin, we found that males grew more colorful plumage than females. HPLC analyses of feather pigments revealed that male finches incorporated a higher concentration of carotenoids into their pigmented feathers than females. Compared to females, males also deposited significantly more canary xanthophyll B into feathers when fed a plain-seed diet and a greater concentration and proportion of canthaxanthin when fed a carotenoid-supplemented diet. These results indicate that sex-specific expression of carotenoid pigmentation in American goldfinches may be affected by the means by which males and females physiologically utilize (e.g. absorb, transport, metabolize, deposit) carotenoid pigments available to them in the diet.
Assuntos
Carotenoides/farmacologia , Plumas/efeitos dos fármacos , Pigmentação/efeitos dos fármacos , Caracteres Sexuais , Aves Canoras/crescimento & desenvolvimento , Animais , Cantaxantina/farmacologia , Carotenoides/administração & dosagem , Carotenoides/análise , Cromatografia Líquida de Alta Pressão , Dieta , Feminino , Masculino , Aves Canoras/fisiologiaRESUMO
Birds display a tremendous variety of carotenoid-based colors in their plumage, but the mechanisms underlying interspecific variability in carotenoid pigmentation remain poorly understood. Because vertebrates cannot synthesize carotenoids de novo, access to pigments in the diet is one proximate factor that may shape species differences in carotenoid-based plumage coloration. However, some birds metabolize ingested carotenoids and deposit pigments that differ in color from their dietary precursors, indicating that metabolic capabilities may also contribute to the diversity of plumage colors we see in nature. In this study, we investigated how the acquisition and utilization of carotenoids influence the maintenance of species-typical plumage pigmentation in male American goldfinches (Carduelis tristis) and northern cardinals (Cardinalis cardinalis). We supplemented the diet of captive goldfinches with red carotenoids to determine whether males, which are typically yellow in color, were capable of growing red plumage. We also deprived cardinals of red dietary pigments to determine whether they could manufacture red carotenoids from yellow precursors to grow species-typical red plumage. We found that American goldfinches were able to deposit novel pigments in their plumage and develop a striking orange appearance. Thus, dietary access to pigments plays a role in determining the degree to which goldfinches express carotenoid-based plumage coloration. We also found that northern cardinals grew pale red feathers in the absence of red dietary pigments, indicating that their ability to metabolize yellow carotenoids in the diet contributes to the bright red plumage that they display.
Assuntos
Carotenoides/metabolismo , Dieta , Pigmentação , Aves Canoras/fisiologia , Animais , Carotenoides/farmacologia , Plumas , MasculinoRESUMO
This study explored associations for having a hero with aspects of adolescents' self-concept for 168 high school students who completed Harter's Self-per ception Profile and questions about their heroes. Having a hero was related to having a stronger sense of social acceptance, romantic appeal, and athletic competence and a weaker sense of scholastic competence.