Study Of Resilience Related Protein Of Antarctic Sea-ice Bacteria Pseudoalteromonas Sp.

The earth’s poles are covered with vast sea ice, which provides an extremelycomplicated living space for sea-ice bacteria adhering inside. Sea-ice bacteria willembed into solid sea-ice salt capsule from liquid seawater within a very short time,and its living environment changes tremendously such as a sudden increase insalinity and rapid decline in temperature. For the purpose of the growth, survivaland proliferation, sea-ice bacteria have been altered complicatedly in physiolgy,metaboly and inheritance which make itself maintain special physiological andbiochemical characteristics and gene expression regulation mechanism. Thus,Antarctic sea-ice bacteria are typical material for research on biological adaptationmechanisms under resistant conditions, which are very important for study on salttolerance and related protein.Antarctic sea-ice bacteria were taken as experiment material. Three highsalt-tolerance bacteria strains ANT88, ANT319, ANT518were isolated by primaryscreening, and ANT319showed the best growth performance. Gene sequencehomology and phylogeny of the three strains were analyzed, showing that they werePseudoalteromonas sp., which belongs to the typical strains in Antarctic sea-icebacteria, the research for its adaptation mechanisms being important scientificsignificance.Then strain ANT319was chosen to be the research object, and itsability in salt tolerance and antioxidant enzymes system activity had been studiedunder different salinity conditions. The results showed that the optimum salinity forANT319was9%. With salinity increasing, the protein content and membranepermeability increased while SOD and POD enzyme activities presented trend ofincreasing firstly and decreasing later, meanwhile CAT activity and MDA keptsteady. The law of indexes changes revealed the mechanism of salinity tolerance ofstrains preliminarily. The differential protein map the ANT319cell expressed wasanalyzed with proteome technology under different salinity, which indicated thatsalinity increase could induce synthesis of CspA-like protein and Cold-shockDNA-binding protein idetified by mass spectrometry, assuming they played animportant part in the mechanism of salinity tolerance. In addition, gene cloning andexpression for thioredoxin which was an important component of the antioxidantsystem of the Antarctic sea-ice bacteria had been conducted, the full-length DNAsequence of the gene is327bp and has a complete open reading frame encoding108amino acids conserved catalytic sites WDGPC. Phylogenetic analysis showed thatthe gene has the highest homology with P.haloplanktis.TAC125, which providing new stress resistance gene for bio-genetics and breeding.