【摘要】 以南极菌Pseudoalteromonas sp.S-15-13为材料,采用实时定量PCR的方法研究了温度、冻融循环及培养基中NaCl、葡萄糖含量和pH对多糖合成关键酶基因ugd表达水平的影响。结果表明,低温有利于ugd的表达,在2℃和10℃培养温度下,培养24h后ugd的表达量约为20℃时的4倍;冻融循环后,ugd的表达量上调,第2个冻融循环后ugd的表达量较对照提高了6.85倍;NaCl对ugd的影响表现为低促高抑,即NaCl含量为6.0%时ugd的表达量是对照(3.0%)的3.97倍,但含量达9.0%时ugd表达量仅为对照的2/5;葡萄糖能够提高ugd的表达量,当含量为2.0%时ugd表达量为对照的13.68倍;在一定范围内(pH5.0—8.0),pH的改变会促进ugd的表达,当pH为6.0时ugd表达量约为pH7.0时的2.15倍。更多还原

【Abstract】 As a key enzyme, UGD plays important roles in synthesis of polysaccharides, on which this paper studied. In this paper, effects of environmental factors(such as: temperature, freeze-thaw, NaCl, glucose and pH) on ugd gene expres sion was studied with real-time PCR for Pseudoalteromonas sp.S-15-13 isolated from sea ice (62°00?S, 68o30?E)samples collected by the 19th Antarctic Scientific Research Expedition of China during 2002—2003. It was showed that the ugd expression level of S-15-13 grown at 2℃ and 10℃was about 4 times compared to that of grown at 20℃ after 24h culture; the expression level of ugd was 6.85times higher than the untreated sample after two freeze-thaw cycle of S-15-13; 6.0% NaCl could increase the expression level of ugd nearly three times compare to that of 3.0%, but when the NaCl concentration up to 9.0% the expression level of ugd was only 2/5 of control; the expression level of ugd was improved 12.68 times when the glucose concentration added to 2.0% compared to that of control; pH change (5.0—8.0)will promote the expression of ugd, 2.15 times expression was enhanced when pH down to 6.0 from 7.0. This study on ugd may deepen our understanding of the adaptation mechanism of Antarctic bacteria living in harsh environment.更多还原