关键词: 南极, Pseudoalteromonas sp. ANT319, 耐盐性, 海冰

Abstract: Over long periods of evolution, Antarctic sea-ice microorganisms obtained special physiological and biochemical characterristics and gene expression regulation mechanisms to adapt extreme environment. To learn more about the adaption mechanism of the Antarctic microorganisms, the strains growth, total protein content, permeability of cell membrane, malondialdehyde and antioxidant enzymes system activity including SOD, POD and CAT had been studied under different salinity conditions of 3%~9% based on the Pseudoalteromonas sp. ANT319, which belongs to the typical genus in Antarctic bacteria. The results showed that the optimum salinity for P. sp. ANT319 was 9%. With salinity increasing, the total protein content and membrane permeability increased while SOD and POD enzymatic activities presented a trend of increasing firstly with the highest at 9% and then decreasing later, meanwhile CAT activity and MDA kept steady. Therefore, as the salinity increased, total proteins content increased as  result of cell membranes damaged gradually, meanwhile, the strain produced more proteins to remove harmful reactive oxygen species caused by salt stress and the activities of antioxidant enzymes were also enhanced. These results revealed the salinity tolerance mechanism of sea-ice bacteria preliminarily.

Key words: Antarctic;Pseudoalteromonas sp. ANT319, salt tolerance, sea-ice