| The Antarctica plays an important role in the study of global changes and it is the only land without large-scale human activities influence which makes it is sensitive to the global climate changes. Penguin is the most impartment factor in the Antarctic environment and its dropping sediment records the history of the population and the distribution change on the Ardley Island. It is possible for us to detect the relation among ecology, environment changes, climate variance and human activities by studying the penguin dropping sediment.The sediment core was collected from the shore on the Ardley Peninsula during the eighteenth China Antarctic Research Expedition using a 12cm-diameter PVC pipe. The number of cultural bacteria was higher than other areas of the Antarctic and there was an obvious decrease at 7th layer. The total DNA of every layer was extracted and the 16S rDNA was amplified by PCR. The diversity of 16S rDNA was studied by RFLP (Restriction Fragment Length Polymorphism) and phylogenetic analysis. In the sediment, bacteria belonging to the CFB (Cytophaga-Flexibacter-Bacterioides) group and the β-Proteobacteria, γ-Proteobacteria were the main groups. The 16S rDNA diversity of 7th layer was different from that of other layers, including the analysis of RFLP, gene type and the population of CFB group. And the population of β-Proteobacteria showed inverse ratio with that of CFB group. Fifteen percent of the total strains were related with degradation of hydrocarbon and one strain with heavy metal contamination. The contents of amino acid were analyzed and the amount of Cys, Met, Tyr, His and Trp increased at 2nd and 7th layers while other kinds of amino acid decreased. The relationship between microbiology and environment changes and human activities influence was assumed based on these results.More than 50% of the earth's surface is covered by deep-sea area. Deep-sea microorganism has especial histiocyte system, metabolism and enzyme system in long-term evolution in deep-sea environment. And the microbial proteases are among the most important hydrolytic enzymes and have been studied extensively since the advent of enzymology. The bulk uses of alkaline proteases in industrial sectors are including food and feed industry, peptide synthesis, leather industry, management of industrial and household waste, photographic industry.A strain named DY-A which produces protease was isolated from deep-sea sediment. It was identified as Pseudomonas spp. with 16S rDNA sequence and phylogenetic analysis. It can grow at a wide range of pH and salt concentration and best at 10.C. The strain produced maximum protease activity after growth at 10.C, initial pH 10.0 and inoculation volume 0.5% for 48~72h on a shaker by speed of 200r/min. Protease was purified by Sephadex G-100 and CL-6B DEAE Sepharose. The optimum pH and temperature for the protease activity are pH 10.0 and 40.C. The enzyme is cold-active alkaline serine protease. Some other properties ofthe strain and the protease were discussed in detail. Total DNA of strain DY-A was extracted and clone of the protease gene was in progress... |
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