南极海冰细菌科尔韦尔氏菌低温适应性的初步研究

Preliminary study on low-temperature adaptation of Antarctic sea ice bacterium Colwellia sp.

以南极海冰细菌(Colwellia sp.NJ341)为材料,从蛋白质、酶和脂肪酸等方面对0℃下低温适应性进行初步探讨。结果表明,与15℃相比,0℃下菌株NJ341的生长量和蛋白质含量处于较高值;不饱和脂肪酸C16∶1ω9和C16∶1ω7含量显著增加(P<0.05),而C18∶1显著下降(P<0.05);脂质过氧化的重要参数丙二醛(MDA)含量极显著增加(P<0.01),但在4^-5℃变化幅度不大;谷胱甘肽硫转移酶(GST)活力在8~22℃温度范围内没有检测到,而在4^-5℃范围内其活力极显著增加(P<0.01)。这些重要生理参数的变化将有助于了解低温微生物在接近冰点温度下的适应机制。

Antarctic psychrophilic bacterium can survive and thrive in channels or pores at low temperature and high salinity water in Antarctic ice layer.In this study,Antarctic sea ice bacterium Colwellia sp.NJ341,isolated from Antarctic sea ice samples collected in 18th Chinese Antarctic expedition during 2001-2002,was used as study material.The protein,enzyme,cell fatty acid contents of Colwellia sp.NJ341 growing at different temperatures were analyzed,and the results showed that the extent of growth and protein content kept high level at 0 ℃.Colwellia sp.NJ341 growing at 0 ℃ exhibited higher growth rate and protein content compared with those at 15 ℃,with notably increased unsaturated fatty acid such as C16∶1ω9 and C16∶1ω7(P<0.05),but unsaturated fatty acid C18∶1 notably decreased(P<0.05).Malondialdehyde determination(MDA) as index of lipid peroxide notably increased at 4 ℃(P<0.01),but its content kept steady at temperatures ranging from 4 ℃ to-5 ℃.However,we found that GST activity was not detected at temperatures ranging from 8 ℃ to 22 ℃,while MDA content notably increased at temperatures ranging from 4 ℃ to-5 ℃.These changes of important physiological parameters would offer significant information to understand the microbial low-temperature adaptation mechanism at near-freezing temperatures.