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Proceedings. Biological sciences / The Royal Society ; 272(1577): 2181-2188, Oct. 2005. graf
Artigo em Inglês | MedCarib | ID: med-17650


Regardless of their origins, mate preferences should, in theory, be shaped by their benefits in a mating context. Here we show that the female preference for carotenoid colouration in guppies (Poecilia reticulata) exhibits a phenotypically plastic response to carotenoid availability, confirming a key prediction of sexual selection theory. Earlier work indicated that this mate preference is genetically linked to, and may be derived from, a sensory bias that occurs in both sexes: attraction to orange objects. The original function of this sensory bias is unknown, but it may help guppies find orange-coloured fruits in the rainforest streams of Trinidad. We show that the sensory bias also exhibits a phenotypically plastic response to carotenoid availability, but only in females. The sex-specificity of this reaction norm argues against the hypothesis that it evolved in a foraging context. We infer instead that the sensory bias has been modified as a correlated effect of selection on the mate preference. These results provide a new type of support for the hypothesis that mate preferences for sexual characters evolve in response to the benefits of mate choice--the alternatives being that such preferences evolve entirely in a non-mating context or in response to the costs of mating.

Animais , Masculino , Feminino , Sexualidade , Fenótipo , Comportamento Sexual Animal , Carotenoides , Poecilia/genética , Poecilia/metabolismo , Poecilia/fisiologia , Trinidad e Tobago
Proceedings. Biological sciences / The Royal Society ; 271(1534): 45-49, Jan. 2004. graf
Artigo em Inglês | MedCarib | ID: med-17609


Rarely are the evolutionary origins of mate preferences known, but, recently, the preference of female guppies (Poecilia reticulata) for males with carotenoid-based sexual coloration has been linked to a sensory bias that may have originally evolved for detecting carotenoid-rich fruits. If carotenoids enhance the immune systems of these fishes, as has been suggested for other species, this could explain the origin of the attraction to orange fruits as well as the maintenance of the female preference for orange males. We used the classic immunological technique of tissue grafting to assay a component of the immune response of guppies raised on two different dietary levels of carotenoids. Individual scales were transplanted between pairs of unrelated fishes, creating reciprocal allografts. Transplanted scales were scored on a six-point rejection scale every day for 10 days. Five days later, the same pairs of fishes received a second set of allografts and were scored again. Compared with low-carotenoid-diet males, high-carotenoid-diet males mounted a significantly stronger rejection response to the second allograft but not to the first allograft. High-carotenoid-diet females, however, showed no improvement in graft rejection compared with low-carotenoid-diet females. To our knowledge, this is the first experimental evidence for sex-specific effects of carotenoid consumption on the immune system of a species with carotenoid-based sexual coloration. These results are consistent with the hypothesis that the mate preference for carotenoid coloration is maintained by the benefits to females of choosing healthy mates, but they cast doubt on the idea that the benefits of carotenoid consumption, per se, could account for the origin of the preference. The sex-specificity of carotenoid effects on allograft rejection in guppies provides indirect support for the general hypothesis that males pay an immunological cost for sexual ornamentation.

Animais , Masculino , Feminino , Estudo Comparativo , Research Support, U.S. Gov't, Non-P.H.S. , Carotenoides/imunologia , Melanócitos , Pigmentação/imunologia , Pigmentação/fisiologia , Poecilia/imunologia , Poecilia/fisiologia , Fatores Sexuais , Transplante Homólogo/imunologia , Trinidad e Tobago
J Agric Food Chem ; 47(10): 4038-45, Oct. 1999.
Artigo em Inglês | MedCarib | ID: med-741


Pure Valencia orange (Citrus sinensis) juices (64 samples) from Spain, Israel, Belize, Cuba, and Florida, harvested during two seasons (1996-1997 and 1997-1998), were analyzed for their carotenoid profiles. The detection of saponified carotenoid pigments has been achieved and quantified using a photodiode array detection monitored at 350, 430, and 486 nm. Carotenoid pigments commonly found in the orange variety Valencia have been separated on a polymeric C-30 column using a ternary gradient as eluent. Pure Valencia juices from oranges grown in the Mediterranean regions (Israel and Spain) have a high carotenoid content, expressed in beta-carotene (5-18 and 14-35 mg L(-)(1), respectively), compared to those grown in tropical and subtropical regions (Cuba, Belize, and Florida) (4-10, 2-8, and 5-10 mg L(-)(1), respectively). Quantitative results allowed the differentiation of Valencia variety geographical origins, in particular, the Mediterranean area from tropical and subtropical areas, using multidimensinal analyses of carotenoid contents. (AU)

Estudo Comparativo , Bebidas , Carotenoides/análise , Citrus/química , Citrus/normas , Belize , Cromatografia Líquida , Cor , Cuba , Florida , Israel , Espanha
West Indian med. j ; 47(suppl. 2): 36, Apr. 1998.
Artigo em Inglês | MedCarib | ID: med-1863


Nutritional deficiencies would appear to be an important determinant of morbidity in homozygous sickle cell (SS) disease. This is evidenced by the growth and development deficits which are observed in children with SS disease. In a study of the nutritional status of Jamaican children with SS disease aged 3 to 6 years, serum samples from blood taken after an overnight fast in the SS children and children of the same age with normal haemoglobin (AA) were collected. Micro-nutrient analyses of these serum samples for vitamin A (retinol) and vitamins E (alpha and gamma tocopherol) and the carotenoids, beta-carotene and lycopene were carried out using high performance liquid chromatography (HPLC). The results suggest that in children with SS disease several of the micro-nutrients which are essential for maintaining optimal antioxidant status are found in decreased amounts in serum. The confirmation of these micronutrients deficiencies in SS children provide the basis fo further exploration of their interrelationshipo with the growth and development deficits in this population. (AU)

Pré-Escolar , Humanos , Anemia Falciforme/complicações , Deficiência de Vitamina E/complicações , Deficiência de Vitamina A/complicações , Carotenoides , Estado Nutricional , Jamaica
Am J Clin Nutr ; 64(5): 726-30, Nov. 1996.
Artigo em Inglês | MedCarib | ID: med-2489


Suggestions that carotenoid-containing foods are beneficial in maintaining health have led to several studies of circulating carotenoid concentrations of adults. Because few data are available for children, we report serum carotenoid concentrations of 493 children in Belize. Carotenoid concentrations were determined as part of a survey of vitamin A status of children, most between 65 and 89 mo of age. Reproducibility was tested by collecting a second blood samples 2 wk after the first collection from a subset of children (n = 23) who consumed their habiitual diet with no treatment during the interim. Predominant serum carotenoids were lutein/zeaxanthin and beta-carotene, which accounted for 26 percent and 24 percent of median total carotenoids, respectively. The three provitamin A carotenoids, alpha- and beta-carotene and beta-cryptoaxnthin, constituted 51 percent od median total carotenoid concentrations. Partial correlations of each carotenoid with fasting retinol concentrations indicated that beta-carotene had the highest correlation. Concordance correlation coefficients (rc) for fasting carotenoid concentrati9ons determined 2 wk apart were > or = 0.89 for lycopene, beta-cryptoxanthin, and alpha- and beta-catotene. The rc for lutein/zeaxanthin and total carotenoids was lower, 0.59 and 0.68, respectively, because of higher lutein/zeaxanthin concentrations at the second sampling than at the first. The reproducibility of the concentrations suggest both that individuals have characteristic profiles and that serum carotenoid concentrations can be measured randomly over > or =2 wk without significant bias. (au)

Criança , Pré-Escolar , Humanos , Carotenoides/sangue , Carotenoides/sangue , Carotenoides/sangue , Cromatografia Líquida de Alta Pressão , Dieta/normas , Vitamina A/sangue , Vitamina A/uso terapêutico , Deficiência de Vitamina A/sangue , Deficiência de Vitamina A/tratamento farmacológico , Deficiência de Vitamina A/epidemiologia , Luteína/sangue