ABSTRACT
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.
Subject(s)
Animals , Anti-Infective Agents , Metabolism , Pharmacology , Bacterial Physiological Phenomena , Fungi , Physiology , Marine Biology , Mollusca , Microbiology , Penicillium , Metabolism , Pseudomonas aeruginosa , Metabolism , Virulence , Quorum Sensing , VirulenceABSTRACT
Objective To observe the therapeutic effect of chitosan oral ulcer spray in treatment of recurrent aphthous ulcer(RAU).Methods Sixty patients suffered with RAU were randomly divided into two groups.The test group was treated with chitosan oral ulcer spray,while the control group was given a traditional Chinese medicine named Xileisan.To evaluate the efficacy according to a specialized evaluate standard.Results The disease course of test group was shorter than that of the control group.The test group was more effective in mitigating the pain of RAU than that of the control group.ConclusionThe efficacy of chitosan oral ulcer spray in treatment of RAU is superior to Xileisan.
ABSTRACT
Objective To study the effects of polypeptide from Chlamys farreri(PCF) on PI3K/Akt and ASK1-JNK signal transduction pathway in thymocytes after ultraviolet B radiation.Methods Murine thymocytes were exposed to UVB radiation.The reactive oxygen species(ROS) level in thymocytes was detected by colormatching.The activation of Akt was investigated by western-blot.ASK1,JNK activation,mitochondria memberine potential and DNA ladder were also investigated after pretreatment with or without PI3K/Akt pathway inhibitor LY294002.Results PCF could activate Akt,inhibit the activation of the ASK1 apoptosis pathway in murine thymocyte radiated by UVB.Conclusion PCF decreased ROS level,increased Akt activity and inducing ASK1 degradation leading to the inhibition of ASK1-JNK induced apoptosis.