RESUMO
Ghrelin, neuropeptide Y (NPY) and cholecystokinin (CCK) all have important roles in the regulation of feeding in fish and mammals. To better understand the role of the three peptides in appetite regulation in the early developmental stages of blunt snout bream (Megalobrama amblycephala), partial cDNA sequences of ghrelin, NPY and CCK genes were cloned. And then, real-time quantitative PCR and RT-PCR were used to detect and quantify the mRNA expressions of these genes from zygotes to larvae of 50 days after hatching (DAH). Ghrelin, NPY and CCK were all expressed throughout the embryonic and larval development stages, and the expression levels were higher in larval stages than in embryonic stages. Ghrelin and NPY mRNA expressions were upregulated at 1, 3, 5 DAH, while CCK mRNA expression was reduced significantly at 3 DAH. The mRNA expression levels of three genes in larvae varied significantly until 30 DAH. In adult fish, all three peptides were detected to be expressed in brain and several peripheral tissues. Ghrelin mRNA was mainly expressed in the intestine, whereas NPY and CCK mRNAs were mainly expressed in the brain. Taken together, these results indicate that ghrelin, NPY and CCK may have roles in early development and participate in the regulation of feeding of larvae in blunt snout bream and will be helpful for further investigation into feed intake regulation in adults of this species.
Assuntos
Colecistocinina/metabolismo , Cyprinidae/crescimento & desenvolvimento , Cyprinidae/metabolismo , Regulação da Expressão Gênica no Desenvolvimento/fisiologia , Grelina/metabolismo , Neuropeptídeo Y/metabolismo , Sequência de Aminoácidos , Animais , Sequência de Bases , Colecistocinina/genética , Clonagem Molecular , Grelina/genética , Larva/metabolismo , Dados de Sequência Molecular , Neuropeptídeo Y/genética , RNA Mensageiro/genética , RNA Mensageiro/metabolismoRESUMO
The method for separation and determination of tyramine by reversed-phase high performance liquid chromatography has been established. The effects of mobile phase on mechanism of separation based on the ion interaction are discussed. Using C8 alkyl bonded phase and 40% methanol-water solution containing Trisperchlorate as pH buffer (adjusted pH to 7.9) and ion interaction reagent and applying p-toluene sulfonamide as internal standard substance, the tyramine obtained from decarboxylation of p-tyrosine was determined. The RSD of determination was 0.66%(n = 11). The recoveries of sample were between 99.33% and 100.38%.
Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Tiramina/isolamento & purificação , Alquilação , Concentração de Íons de Hidrogênio , Tiramina/análiseRESUMO
It is recognized that aluminium (Al) is a potential environmental hazard. Acidic deposition has been linked to increased Al concentrations in natural waters. Elevated levels of Al might have serious consequences for biological communities. Of particular interest is the speciation of Al in aquatic environments, because Al toxicity depends on its forms and concentrations. In this paper, advances in analytical methodologies for Al speciation in environmental and biological samples during the past five years are reviewed. Concerns about the specific problems of Al speciation and highlights of some important methods are elucidated in sections devoted to hybrid techniques (HPLC or FPLC coupled with ET-AAS, ICP-AES, or ICP-MS), flow-injection analysis (FIA), nuclear magnetic resonance (27Al NMR), electrochemical analysis, and computer simulation. More than 130 references are cited.