The investigation of inhibiting quorum sensing and methicillin-resistant Staphylococcus aureus biofilm formation from Liriodendron hybrid

The quorum sensing [QS] of pathogens has been found to affect their biofilm forming ability, making it a potential target for anti-microbial therapy. The present research aimed to evaluate the anti-QS activities of different extracts and isolated phytochemicals from Liriodendron hybrid barks and their roles in the inhibition of the growth and biofilm formation of methicillin-resistant Staphylococcus aureus [MRSA]. The assays on the inhibition of QS by the five extracts [n-hexane, dichloromethane, ethyl acetate, acetone, and methanol] and eight isolated compounds were carried out by using both the indicator strains Chromobacrerium violaceum CV026 and C. violaceum ATCC12472. The in vitroeffects of the five extracts and eight isolated compounds on MRSA biofilm were also preliminarily evaluated using crystal violet micro titer plate assays. The results suggested that the dichloromethane extract showed anti-QS and MRSA biofilm inhibitory activities and the n-hexane extract possessed only MRSA biofilm inhibitory effect. The dichloromethane extract could serve as a source for developing bacterial intervention strategies targeting microbial QS system. All eight isolated compounds showed no anti-QS and biofilm formation inhibiting activities. So further researches are still being required to purify and identify the compounds possessing anti-QS and biofilm inhibitory effects from the dichloromethane and n-hexane extracts

Genetic Analysis of VP_1 Sequences of Enterovirus 71 Isolated from Patients of Hand,Foot and Mouth Disease in Beijing,2008 / 中国疫苗和免疫

Objective To get genetic information of VP 1 coding region of HEV 71 in Beijing in 2008.Methods Enteroviruses were isolated from samples of throat swabs collected from 33 HFMD patients within 3 days after onset by rhabdomyosarcoma(RD) cells and identified by RT-PCR method with specific primers to human enteroviruses,then VP 1 coding region was amplified and sequenced by Sanger dideoxy.Bioedit 7.0.5 and MEGA3.1 were used for the nucleotide sequence alignment and phylogenetic analysis.Results 16 virus strains were isolated from 33 samples,of which 14 strains were identified as HEV 71 and 2 were CVA 16,and 1 was co-infected with CVA 16 and HEV 71.Sequence analysis of VP 1 nucleotide sequences of 10 HEV 71 isolates showed that homologous analysis of nucleotide identity amino acid 95.5%～100% and 98.9%～100% respectively;representative strains of Fuyang in 2008,nucleotide identity was 95.4%～99.1%;with representative strain of C 4 nucleotide identity was over 92%.Phylogenetic analysis of HEV 71 strains for the nucleotide sequence of VP 1 coding region clarified that the HEV 71 isolates in Beijing belonged to C 4a cluster of C 4 sub-genotype and 10 strains formed four relatively separated clusters.Conclusions The HEV 71 viruses isolated from children of HFMD in Beijing belonged to C 4 sub-genotype,and C4a cluster which was the predominant in China since 2004.According to phylogenetic analysis,HEV 71 which belonged to more than 4 different clusters were circulating in Beijing in 2008.More virological suggestion for disease control and prevention,and information of HEV 71 molecular epidemiology need to be collected urgently due to the successive large epidemic of HEV 71 in China.

Molecular Epidemiological Research on Enterovirus 71 / 中国疫苗和免疫

Objective Enterovirus 71(EV71) is one of the important etiologic agent for young children,which can cause various kind of diseases.EV71 can cause HFMD outbreak in a large scale and encephalmeningitis to death.This review introduced the research method and status of EV71 molecular epidemiology,examined and analyzed the evolution of EV71,summerized all genotype/subgenotype for EV71.the geographic and time distribution.