Study On Bacterial Community Structure And Biogeochemical Processes Of Sediment From Near-shore Marine-cultural Region

Their taxonomy and systematic evolutionary are studied by their morphologic cheracteristics, physiological and biochemical properties, and 16S rDNA sequences. The molecular biological techniques, such as PCR, ARDRA pattern analysis and sequencing 16S rDNA, are used to study their polyphasic taxonomy. Applying analytical method of ARDRA pattern on environment microbical ecology is also discussed. Bacterial community structure and quantity of sediment from near-shore marine-cultural region located in DongShan, FuJian province of China are studied in the thesis. Based on the methods of CFU and MPN, quantity and community structure of bacteria in the samples of the sediment have been analyzed, from which 106 strains were isolated.The results indicate that there are morphologic, physiological and biochemical diversities among bacteria from the sediment. Diversity of 16S rDNA sequences of these strains is showed by ARDRA pattern analysis, these results are corresponded with that of morphologic cheracteristics, physiological and biochemical properties of the bacterial strains.The results show that 87% of isolates are the most aboundent populations and belong to endospore-forming bacteria, and the others are the lowest population and belong to non spore-forming bacteria. Bacillus, Halobacillus are the most aboundent populations among endospore-forming bacteria, and widely distribute in sediment. Microbium, Planococcus, a few gram-negative bacteria are the lowest populations, and mainly distributed on the top of sediment.Some strains might be novel genus or species, based on their 16S rDNA sequence. The bacterial strain 2-2 has been identified. The similarity of its 16S DNA sequence is lower than 96% to Bacillus pumilus, and its morphologic cheracteristics, physiological and biochemical properties, components of cell's wall are also different from those of B. pumilus. These results strongly suggest that strain 2-2 is a novel species of the genus Bacillus and the name Bacillus catenulatus is proposed for this strain. The strain was found to produce the differential phenotypes of cells and this phenotypic difference is confirmed by growing-cells, colonies, 16S rDNA sequence contrasted. We try to widen the view to study the differential cell of Bacillus by extracting plasmid and analysised SDS-PAGE of cell's protein.