China remains by far the largest aquaculture producer in the world. However, biofilms formed by pathogenic Vibrio strains pose serious problems to marine aquaculture. To provide a strategy for biofilm prevention, control, and eradication, extracts from 88 marine actinomycetes were screened. Thirty-five inhibited the biofilm formation of Vibrio harveyi, Vibrio vulnificus, and Vibrio anguillarum at a concentration of 2.5% (v/v). Thirty-three of the actinomycete extracts dispersed the mature biofilm. Six extracts inhibited the quorum-sensing system of V. harveyi by attenuating the signal molecules N-acylated homoserine lactones' activity. Strain A66, which was identified as Steptomyces albus, both attenuated the biofilms and inhibited their quorum-sensing system. It is suggested that strain A66 is a promising candidate to be used in future marine aquaculture.

Inhibition of Vibrio biofilm formation by a marine actinomycete strain A66

Identification and evaluation as a DNA vaccine candidate of a virulence-associated serine protease from a pathogenic Vibrio parahaemolyticus isolate.

The paper deals with the morphology and biochemical characteristics of patho-genic bacteria that are found in infected shrimps in the intensive cu1ture pond. The bacte-ria are isolated and purified from haemolymph and hepatopancreas of the infectedshrimps, and the pathogenicity of isolated bacteria and the same infected symptoms arefound after the isolated bacteria infect shrimps. Also the bacteria are isolated and puri-fied from haemolymph and hepatopancreas of the re--infected shrimps. The isolated andre--iso1ated bacteria in this study all are gram negative, short rods with a single polar fla-gellum, resistant to O/129, oxidase and catalase positive, salt requirement, growing wellin 3 %, 6 %,8 % NaCl and on TCBS, but no growth in l0% NaCl. The bacterium can uti-lize citrate, mannitol, fructose, galactose. They don't ferment lactose, inositol, sorbitol,xylose and melibiose. V--P reaction, sulfide production, arginine dighdrolase and tryptopl-can deaminase of this bacterium is negative. Bacteriological identification shows the iso-lated bacterium is Vibrio parahaemolyticus.

Tao Bao

Papers

Studies on pathogenetic biology of vibriosisoccurring in penaeus monodon