| 其他摘要 | Amphibian skin is a vital organism that fulfills many essential functions, including water-salt balance, defense, respiration, et.al. Amphibian skin can secret large array of compounds with specific bioactivities, which is mainly composed by many different types of peptides or proteins. The research on these secreted compounds can provide 1). Candidates for the explore of molecular with therapeutic potentiality, such as anti-infectious agents, novel types of antioxidants, et.al; 2). Clues to understand the molecular basis for the adaptation to surroundings. Therefore, the research on the amphibian skin peptides is very important for both applied science and basic science.In this paper, we have performed the following 4 researches:1. Skin antimicrobial peptidomics of 9 China-native odorous frogs: Through the combinational methods of peptidomics and genomics, we identified 728 antimicrobial peptides (AMPs), which accounted for more than 30% AMPs yet found in nature, from the skin of Odorrana andersonii, O. rotodora, O. wuchuanensis, O. margaratae, O. hejiangensis, O. schmackeri, O. livida, O. tiannanensis and O. macrotympana. These AMPs were classified into 97 different families and 71 groups were named for the first time. Our results revealed that: A). Odorous frog is the species with the highest AMP diversity yet found in nature, amphibian skin is jewel of great price for the explore of new anti-infectious agents; B). The post-translational modifications didn’t occur in the AMPs from odorous frogs, the majority (about 90%) of odorous frog skin AMPs contained a C-terminal disulfide bridge; C). Identical AMPs were widely distributed in different amphibian skins and this phenomenon updated the traditional views；D). Except for the role of direct-killing pathogens, AMPs also play roles as antioxidants and immunomodulators; E). Amphibian skin AMPs showed potentiality to be insulin releasing activators. The great diversity AMPs provides us clues to understand the molecular basis of the defensing function of amphibian skins and the great power of the amphibian skin innate immune system. 2. The traditional methods to identify amphibian AMPs rely heavily on the large amount of skin secretions, however, the amount of many amphibians is decreasing sharply owing to many factors, besides, many amphibians are of short stature, it is not likely to obtain enough skin secretion to initial the identify of AMPs. However, amphibian skins are very important for explore of new types of anti-infection peptide agents; therefore, it is a crucial problem to identify AMPs efficiently at the lowest cost of amphibian samples. In this research, with a specific 5’PCR primer, Rana5’AMP primer (5’-CCAAA(G/C)ATGTTCACC(T/A)TGAAGAAA-3’)，we identified 12 novel AMPs from a single specimen of Rana limnocharis, R. exilispinosa and Amolops afghanus. Like the AMPs from other ranid frogs, all these AMPs contained a C-terminus cyclic motif. Based on the similarities of primary structure, these AMPs were divided into Brevinin-1, Brevinin-2, Esculentin-1, Esculentin-2, Nigrocin and an initially named family Limnochariin-1. The synthetic peptides showed inhibitory effects on the growth of E. coli, C. albicans, S. aureus and B. pyocyaneus. With the help of this Rana5’AMP primer and at the lowest cost, we could identify skin AMPs rapidly from the skin of ranid frogs by ‘shot-gun’ method. Besides, this research also provided clues for the AMPs identification from other amphibians.3. The topic that concerned on the molecular basis of adaptation to high-altitude surroundings is a hot spot in biology, however, explore and explanation of this important issue are mainly from genomic information of homothermal animals. Amphibian, which belonged to poikilothermal animals, is an important link between aquatic and terrestrial organisms, however, the molecular basis of adaptation to high-altitude surroundings is little known. The previous reports have revealed that an antioxidant peptid |
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