LuxS modulates motility and secretion of extracellular protease in fish pathogen .

can cause infections and diseases in a variety of marine vertebrates and invertebrates, which are harmful to the aquaculture industry. The LuxS quorum-sensing system regulates the expression of virulence factors in a wide variety of pathogenic bacteria. In this study, an in-frame deletion of the gene was constructed to reveal the role of LuxS in the physiology and virulence of .

[Optimization of enzymatic extraction of polysaccharide from Dendrobium officinale by box-Behnken design and response surface methodology].

Objective: To optimize the processing of enzymatic extraction of polysaccharide from Dendrobium officinale.

Methods: With phenol-sulfuric acid method and the DNS determination polysaccharide, Box-Behnken response surface methodology was used to optimize different enzyme dosage, reaction temperature and reaction time by using Design-Expert 8.05 software for data analysis and processing.

[Synthesis and bioactivies of salicylic acid-g-chitosan derivatives].

To prepare the derivatives of salicylic acid-g-chitosan and study their synergistic and complementary actions, the synergism of anti-inflammatory action of the derivatives was investigated with the experiments of xylene-induces mice ear edema, the analgesic activities by the tartaric emetic-induced mice twist test and the hot-plate test, and the complementary effects between salicylic acid and chitosan through morphological changes of stomach mucous membrane of rat, separately. The anti-inflammatory activities of salicylic acid-g-chitosan derivatives for anti-inflammatory activities were more potent than that of salicylic acid and chitosan and dexamethasone cream in external use, and more potent than that of aspirin orally. However, immediate analgesic activity of the derivatives was lower than that of aspirin and persistent activity was similar as that of aspirin.