| In order to improve our understanding of disease etiology and develop better diagnostics, it is necessary to research on the microflora associated with diseased animals. Microflora of aerobic heterotrophic bacteria from larvae and postlarvae of Penaeus chinensis were studied.Bacteria isolated from the samples were predominantly Gram-negative. The generic composition, especially the composition of vibrios species were found to vary with different growth stages. Pseudomonas and Aeromonas were the most frequently isolated genera from larvae at initial stages followed by Vibrio alginolyticus and Vibrio harveyi at the following stages subsequently. The high prevalence of Vibrios, especially V. alginolyticus and V. harveyi, was isolated frequently from healthy larvae and postlarvae of P. chinensis. It was suggested that V. harveyi emerging ahead of time due to the worse quality of rearing water was one factor resulting in the epizootic occurrence.On the basis of the research above, distribution of vibrios isolated from 4 species of cultured shrimp larvae in 5 countries were assayed by Biolog GN system. The isolates were isolated mainly from health or diseased shrimp larvae. The distribution of dominant Vibrio species from different species of shrimp and different countries were similar. Vibrio alginolyticus and V. harveyi (or V. carchariae) were dominant and detected in the species of shrimp cultured in the countries in the present study. The Vibrio species isolated from specie of shrimp cultured in different country were a little different from the others. V. harveyi was related to shrimp larvae disease. V. parahaemolyticus was related to adult shrimp disease. V. alginolyticus could be found both from health and diseased shrimp both.The other research was to attempt to make direct links between aquaculture. industrial pollution and their effects on biodiversity.Therefore, 428 isolates of Gram-negative bacteria were isolated in 1999 and 2000 from marine sediment, seawater. seaweed, fish and shellfish, taken from locations in Qingdao. Sampling locations were comprised of industrially and aquaculturally affected sites and a clean, control site. In order to analyze microbial diversity, a polyphasic approach was adopted for characterization of these isolates, specifically through examination of key phenotypic traits, i.e. using Biolog GN MicroPlateTM profiles. Of the 428 Gram-negative isolates examined using Biolog GN, 322 of them were identified at least to the genus level, or were unidentified, whilst 106 of them gave no profile (i.e. had no positive tests or all test results were positive). This technique yielded complex taxonomic data, which were subjected to statisticaland cluster analyses. The application of Biolog-GN method to studies of microbial communities is discussed. Marine bacteria biodiversity adjacent to aquacultural area, industral area compared with clean sites in Qingdao was evaluated according to the results of statistical and cluster analyses by Biolog-GN.It was shown that Virbio is the dominant one among the culturable bacteria in the marine costal environment and marine aquaculture environment and plays a significant role in the environment. Vibrios are active and in high abundance in aquatic ecosystems particularly in eutrophic environments, accounting for up to 14-45 %. The family Vibrionaceae harbours many taxa not yet described. The application of AFLP (amplified fragment length polymorphisms) has been shown to have a tremendous impact in the study of diversity, taxonomy and phylogeny of several bacterial genera. Genomic diversity amongst Vibrio isolates from differrnt sources (76% of them are from marine aquaculture environment) determined by fluorescent ampplified fragment length polymorphism was reported. Almost 47% of these isolates distributed in 31 clusters indicating that many culturable taxa of the Vibrionaceae remaine as yet to be described.Some vibrios FAFLP clusters were not grouped with type strains or reference strains used in this study. The closes...
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