The discovery of quorum sensing (QS) system and its critical role in bacterial virulence have revealed a new way to attack pathogenic bacterium. The pathogenecity of QS deletion mutants decreases significantly. Targeting bacterial QS system is a promising therapeutic approach to control infections and anti-microbial resistance. To obtain natural QS inhibitors from marine organisms, marine fungi (69 strains) were isolated from marine mollusca, and their extracts were screened using improved QSIS2 (Quorum Sensing Inhibitor Selector 2) assay and Chromobacterium violaceum CV026. To improve the efficiency of QSIS2 screening, 2,3,5-triphenyltetrazolium chloride (TTC) staining method was used. Extract from strain QY013 was found to have QS inhibitory activity. Further experiment indicated that pyocyanin in Pseudomonas aeruginosa PAOI and violacein in C. violaceum CV026 were reduced by QY013 extract, without affecting bacterial growth. Morphological and 18S rDNA sequence analysis revealed that strain QY013 was most closely related to Penicillium species. The above results suggest that active constituents from QY013 may be used as novel antimicrobial agents against bacterial infection.
Animals ; Anti-Infective Agents ; isolation & purification ; metabolism ; pharmacology ; Bacterial Physiological Phenomena ; Fungi ; isolation & purification ; physiology ; Marine Biology ; Mollusca ; microbiology ; Penicillium ; isolation & purification ; metabolism ; Pseudomonas aeruginosa ; drug effects ; metabolism ; pathogenicity ; Quorum Sensing ; drug effects ; Virulence ; drug effects

OBJECTIVE： To optimize the ultrasonic extraction technology for Jinjuan shengban capsules. METHODS： Using comprehensive score of indexes as transfer rate of gallic acid， chlorogenic acid， baicalin， aloe emodin and emodin methyl ether， with ethanol volume fraction， ultrasonic power， ultrasonic extraction time and liquid-material ratio as factors， the ultrasound extraction technology of Jinjuan shengban capsules was optimized by Box-Behnken response surface methodology based on single factor test. The validation test was conducted. RESULTS： The best extraction technology was 50-fold 70％ ethanol， extracting 40 min under 300 W. In validation test， average transfer rates of gallic acid， chlorogenic acid， baicalin， aloe emodin and emodin methyl ether were 85.92％， 86.37％， 92.76％， 90.84％ and 87.26％ （RSD＜3.57％，n＝3） in 3 batches of samples； comprehensive score was 88.95％， relative error of which to predicted value of 88.27％ was 1.10％. CONCLUSIONS： The response surface method combined with multi-index comprehensive scoring can be used to optimize the extraction technology of Jinjuan shengban capsules which is simple and stable.