台灣沿岸海水中耐冷細菌多樣性之研究

Abstract

耐冷細菌 (psychrotolerant bacteria) 一般的定義，是指最適生長溫度位於20 - 40 ℃之間，而在低於20 ℃、甚至更低溫的環境下仍能生長良好的細菌。本研究於2006至2007年間，在台灣東北角海岸 (潮境公園、磅磅子、南雅)、宜蘭石城與墾丁南灣等地採集水樣，進行序列稀釋後將稀釋海水塗佈於PY培養基，並放置於4 ℃恒溫箱中培養，藉此篩選出具耐冷特性的分離株。 本研究一共篩選出101株具耐冷特性的分離株，由菌落型態與觸酶、鈉鹽需求、可生長鹽度等表型特性，初步將分離菌株區分為10群；將分離株 16S rDNA 以4種限制酶 (DdeI、RsaI、AluI和HhaI) 進行限制片段長度多樣性 (restriction fragment length polymorphism, RFLP) 分析，共可分為13種基因型。 13種基因型代表株經16S rDNA定序，並與標準菌株序列比對，大致可歸類為Cobetia、Enterobacter、Pseudomonas、Pseudoalteromonas、Psychrobacter、Shewanella、Vibrio等七個菌屬，其中以Pseudoalteromonas屬佔最多數，而Vibrio屬涵蓋了4種基因型。本研究顯示，雖然台灣位處亞熱帶地區，仍有多種耐冷細菌存在沿岸海水中。

Psychrotolerant bacteria are those grow with optima of 20 - 40 ℃, but can grow below 20 ℃, even lower to 0 ℃. These bacteria are called. Attempting to know the diversity of psychrotolerant bacteria in coastal seawater of Taiwan, the sea water samples were collected from northeastern coast of Taiwan (Chaojing Park, Bangbangzih and Nanya), Shihcheng and South Bay during 2006 to 2007. These sea water samples were diluted to 101 - 103 solutions, then plated on PY agar and placed at 4 ℃ to screen out psychrotolernat bacteria. In this study, there were 101 psychrotolernat bacteria strains isolated from the sea water samples. They could be divided into ten groups according to the results of the following tests: colors of the colony, requirement of Na+ for growth, and the ability to grow in 10 % NaCl. These strains were divided into thirteen genotypes within 16S rDNA RFLP after the response by four kinds of restrictive enzyme (AluI, DdeI, HhaI and RsaI). The 16S rDNA of the representative strains of thirteen genotypes were sequenced, and they were belonged to seven genus: Cobetia, Enterobacter, Pseudomonas, Pseudoalteromonas, Psychrobacter, Shewanella and Vibrio. This study indicates that there are many species of psychrotolerant bacteria in coastal seawaters in Taiwan.