• Journal of Microbiology and Biotechnology
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• v.20 no.2
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• pp.271-280
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• 2010

Vibrio alginolyticus, a Gram-negative marine bacterium, is one of the causative agents of fish vibriosis. Its virulence factors and pathogenesis mechanism are barely known, except for some extracellular products (ECPs) that are known to be regulated by quorum sensing system. Therefore, the present study used a microarray to analyze the transcription profiles of the wild-type V. alginolyticus and a deletion mutant of luxO, the pivotal regulator in Vibrio quorum sensing systems, which resulted in the identification of a putative virulence factor, MviN. Quantitative real-time reverse transcription PCR confirmed that the transcription of mviN was upregulated in the luxO mutant when compared with wild-type, and down regulated in a luxO-con complemented strain. Furthermore, Western blotting indicated that MviN was greatly induced during the late-exponential and stationary phases of growth, indicating that the expression of MviN was cell-density dependent and quorum sensing regulated in V. alginolyticus. Meanwhile, the mviN null mutant displayed a much slower growth rate than the wild type, signifying the essential role of MviN in V. alginolyticus. Western blotting also revealed that MviN was present as an extracellular protein in V. alginolyticus. When epithelioma papulosum cyprini (EPC) cells were treated with the ECPs of the mviN mutant, no cytotoxicity was observed, whereas EPC cells treated with the wild type exhibited pathological changes, which increased with the ECPs concentration and treatment time. Therefore, the results demonstrated that MviN is a LuxO-regulated ECPs component and involved in the pathogenicity of V. alginolyticus.

• Korean Journal of Food Science and Technology
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• v.44 no.5
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• pp.621-627
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• 2012

Assessment was made of the effects of Aralia cordata Thunb (DH) on the cell proliferation, inducible nitric oxide synthase (iNOS) mRNA gene expression and nitric oxide (NO) production in RAW 264.7 macrophage cells. For the screening of anti-inflammatory activities, ethanolic extracts of 55 species of traditional herbal medicines were examined for inhibitory effects, and it was confirmed that DH possessed inhibitory effects on NO production. As a result, DH significantly decreased the production of NO and iNOS gene expression at a concentration of $250{\mu}g/mL$. The chloroformsoluble fractionates have the strongest No synthesis inhibitory effect. It is presumed that the inhibition of NO production in LPS-stimulated RAW 264.7 cells by DH components occurred via the modulation of iNOS and DH, and that the active compound from DH may be useful for therapeutic management of inflammatory-associate diseases.