南极冰藻Chlamydomonas sp.ICE-L的抗盐性

以南极冰藻(Chlamydomonassp.)为材料对其抗盐性进行研究,结果表明,冰藻在盐度33下生长良好,在盐度66和99也有较大的生长量,盐度132下也能生存,可以维持原有的生物量,而盐度165对冰藻则是致命的,仅能存活8 d;常温藻(Chlamydomonas monadina)仅能在盐度小于99时生存。由此可以看出,南极藻类较常温藻可抗更高的盐度。同时测定了与盐度变化相关的膜系统变化,与常温藻相比,南极冰藻中的超氧化物歧化酶(SOD)、丙二醛(MDA)和脯氨酸含量较高,而膜透性较低;经盐度99胁迫后,以上4种生化指标都升高。本研究初步结论为,超氧化物歧化酶、丙二醛、脯氨酸和膜透性对南极冰藻的抗盐性研究均有较好的指导意义。这项研究旨为南极冰藻抗盐机理研究提供基础依据。[中国水产科学,2006,13(1):73-78]

Effect of high salinity on cell growth and protein production of Antarctic ice microalgae Chlamydomonas sp. ICE-L

Antarctic ice microalgae Chlamydomonas sp.ICE-L can survive and thrive in Antarctic sea ice.In this study,Chlamydomonas sp.ICE-L could survive at the salinity of 132‰ NaCl.SDS-PAGE showed that the density of 2 bands（26 and 36 kD） decreased obviously at the salinity of 99‰ NaCl compared to at the salinity of 33‰ NaCl.The soluble proteins in Chlamydomonas sp.ICE-L grown under salinity of 33‰ and 99% NaCl were compared by 2-D gel electrophoresis.After shocking with high salinity,8 protein spots were found to disappear,and the density of 28 protein spots decreased.In addition,19 protein spots were enhanced or induced,including one new peptide（51 kD）.The changes of proteins might be correlated with the resistance for Chlamydomonas sp.ICE-L to high salinity.

南极衣藻谷胱甘肽-S-转移酶基因的表达及其对大肠杆菌低温耐受性的增强作用

谷胱甘肽-S-转移酶(Glutathione-S-transferase,GST,EC2.5.1.18)是生物体内一种重要的抗氧化酶,为阐明GST在南极衣藻(Chlamydomonas sp.ICE-L)中的具体地位,采用实时荧光定量PCR对不同温度下南极衣藻的GST基因的表达进行了分析;并构建了原核表达载体pET28a(+)-GST,转化至大肠杆菌BL21(DE3)中进行诱导表达,通过平板培养法探讨了重组菌E.coli BL21(pET28a(+)-GST)对低温胁迫的耐受性。结果显示,GST在0℃时表达量最高,最高可达对照组的两倍多;pET28a(+)-GST重组表达载体在E.coli BL21中实现了高效表达,且主要以包涵体形式存在,经HisTrap HP柱分离纯化获得高纯度的GST融合蛋白,并通过SDS-PAGE及Western blot分析得以验证;对低温胁迫实验发现南极衣藻GST蛋白的表达可以提高重组菌E.coli BL21对低温的耐受性,说明GST基因对南极衣藻适应南极低温环境具有重要作用。