1.Functional analysis of Leptospira interrogans sphingomyelinase hemolysin genes and their transcriptional level alterations in the infected host cells
Jinfang ZHAO ; Xuai LIN ; Jie YAN
Chinese Journal of Microbiology and Immunology 2009;29(5):400-404
Objective To determine the hemolytic activity of products of sphingomyelinase hemolysin encoding genes of Leptospira interrogaas, and the transcriptional level alterations in the infected host cells. Methods By using genomic DNAs of pathogenic L. interrogans serovar serogroup Icterohaemorrhagiae serovar Lai strain Lai and serogroup Pomona serovar Pomona strain Luo, and non-pathogenic L. biflexa serogroup Sama-ranga serovar Patoc strain Patoc Ⅰ as templates, PCRs were performed to amplify entire sph1-sph4 genes. The amplified products were sequenced after T-A cloning. Prokaryotic expression systems of sph1-sph4 genes were re-spectively constructed, and the expressions of target recombinant proteins rSph1-rSph4 were examined by SDS-PAGE. Ni-NTA affinity chromatographic column was used to extract the expressed rSph1-rSph4. Hemolytic ac-tivities of rSph1-rSph4 on sheep blood agar plate were identified. Transcription alterations of sphl-sph4 genes in L. interrogans strain Lai after infected J774A. 1 cells were measured by real-time fluorescence quantitative RT-PCR. Results From genomic DNAs of both L. interrogans strain Lai and Luo, but not from that of L. biflexa strain Patoc Ⅰ , the target fragments of sph1-sph4 genes could be amplified. All the cloned sph1-sph4 genes had 100% nucleotide sequence identities compared to the corresponding reported sequences. The constructed pro-karyotic expression systems were able to efficiently express the target recombinant proteins rSph1-rSph4, respec-tively. All the rSph1-rSph4 had hemolytic activities, and among the four products rSph2 displayed the strongest hemolytic activity. After L. interrogaas strain Lai infecting J774A. 1 cells, the transcriptional levels of sph1-sph4 genes were remarkably up-regulated, especially for mRNA levels of sph2 and sph4 genes. Conclusion sph1- sph4 genes exist only in pathogenic L. interrogans species, and their products have hemolytic activity. The up-regulation of sph1-sph4 gene transcriptional levels in L. interrogans strain Lai after infected cells implies that the sphingomyelinase hemolysins may play important roles in the process of L. interrogans infection in hosts.
2.Progress in research on bacterial HD-GYP domain proteins
Liangliang KONG ; Jie YAN ; Xu′ai LIN ;
Chinese Journal of Microbiology and Immunology 2017;37(3):230-234
Bis-(3′,5′) cyclic di-guanylate (c-di-GMP) is an almost ubiquitous intracellular second messenger in bacteria.Now it is known to regulate complex physiological processes, including mobility, adhesion, virulence and biofilm formation.The level of c-di-GMP is regulated by diguanylate cyclases (DGCs) containing GGDEF domains and phosphodiesterases (PDEs) containing EAL or HD-GYP domains.Recent studies have demonstrated that HD-GYP domain protein is a novel phosphodiesterase, which is also involved in the regulation of c-di-GMP degradation.This review highlights recent advances in the structure and biochemical functions of HD-GYP domain proteins, which might help to further clarify the mechanism of c-di-GMP signal system.
3.The prevalence of hyperuricemia and its relationship to blood lipids in a population for routine check-up in Nanning, Guangxi province
Jie YAN ; Hui TAO ; Jianjun MENG ; Faquan LIN ; Jie ZHANG
Chinese Journal of Endocrinology and Metabolism 2014;30(5):411-414
In 4 602 subjects for routine check-up,blood uric acid,total cholesterol,triglyceride,high density lipoprotein-cholesterol,and low density lipoprotein-cholesterol were determined.Results showed that the overall prevalence of hyperuricemia in Nanning,Guangxi was 19.8% (28.8% in male,9.4% in female).Blood uric acid and lipids in hyperuricemia group were higher than those in normal uric acid group(all P<0.01).Serum uric acid had a positive correlation with total cholesterol,triglyceride,low density lipoprotein-cholesterol,but it was negatively correlated with serum high density lipoprotein-cholesterol.The prevalence of hypercholesterolemia was 30.8%,and that of hypertriglyceridemia was 22.2%.Logistic multi-factor regression analysis showed that men,high total cholesterol,triglyceride,and low density lipoprotein-cholesterol could be independent risk factors for hyperuricemia,and that high density lipoprotein-cholesterol was a protective factor.The prevalence of hyperuricemia in population of Nanning,Guangxi during health examination is high.Hyperuricemia is closely associated with dyslipidemia.Timely intervention of hyperuricemia can reduce the related diseases effectively.
5.Diversity of outer membrane protein expression of Leptospira interrogans during infection of human THP-1 monocytes
Pingping SUN ; Xuai LIN ; Liwei LI ; Jie YAN
Chinese Journal of Microbiology and Immunology 2012;32(3):224-231
ObjectiveTo determine the diversity of outer membrane protein expression of Leptospira interrogans during infection of human THP-1 monocytes,and protein antigen candidates for developing leptospiral genetically engineering vaccines.MethodsThe outer membrane proteins(OMPs) of Leptospira interrogans serogroup Icterohaemorrhagiae serovar Lai strain Lai before or after infection of human THP-1 monocyte line were extracted using Triton X-114 method.The OMPs extracts were separated by two-dimensional gel electrophoresis(2-DGE) and then detected using silver staining method.Four up-regulated and four down-regulated OMPs were selected for hydrolysis by trypsin and then identified by using liquid chromatography-tandem mass(LC-MS/MS) method.The transmembrane regions and signal peptides in the eight target OMPs were analyzed using bioinformatic software.Several real-time fluorescent quantitative RT-PCRs were performed to determine the mRNA level changes of the eight target genes of L.interrogans strain Lai before or after infection of THP-1 cells.The prokaryotic expression systems of target genes were generated and the immunoprutection of target recombinant proteins was determined using leptospire-infected guinea pigs model.ResultsAfter a 60 min infection of THP-1 cells,four OMPs( Loa22,GroEL,F0F1 ATP synthase alpha- and beta-subunits) of L interrogans strain Lai were noticeably up-regulated ( P<0.05 ),while the other four OMPs( FlaB2,LigB,OmpA family protein and OmpA) were significantly down-regulated (P<0.05).The results of real-time fluorescent quantitative RT-PCRs were coincident with those confirmed by the 2-DGE phus silver staining.The bioinformatic analysis indicated that among the eight OMPs,OmpA and OmpA family protein belonged transmembrane proteins,while the rest had no membrane structure.Loa22,LigB and OmpA family protein contained a signal peptide in their sequences.200 μg of the recombinant proteins rLoa22 and rGroEL presented 75.0% immunoprotective rates in the infected guinea pigs.Conclusion An obvious change of the OMP expression map of L.interrogans strain Lai occurs during infection of host cells.The up-regulated leptospiral OM Ps during infection,especially for the GroEL and Loa22 proteins,can be used as the immunogen candidates for developing leptospiral genetically engineering vaccines.
6.Nuclease activity and cytotoxicity to host cells of toxic protein VapC produced by Leptospira species
Xiaoyang XIN ; Xüai LIN ; Liwei LI ; Jie YAN
Chinese Journal of Microbiology and Immunology 2012;32(2):166-171
Objective To determine the function of toxic protein VapC in toxin/antitoxin system of Leptospira species and the cytotoxicity to host cells of the toxic protein.Methods Using genomic DNA of pathogenic L.interrogans serogroup Icterohaemorrhagiae serovar Lai strain Lai as the template,several PCRs were performed to amplify entire vapB,vapC and vapBC genes.Subsequently,the prokaryotic expression systems of vapB,vapC and vapBC genes were constructed.Expression of the target recombinant proteins rVapB and rVapC was detected by SDS-PAGE and the expressed rVapB and rVapC were extracted by NiNTA affinity chromatography.Activity of rVapB and rVapC to lyse the DNAs or RNAs from L.interrogans strain Lai and THP-1 cells were then determined.The changes of transcription and expression of vapB and vapC genes of L.interrogans strain Lai before and after infection of THP-1 cells were detected by real-time fluorescent quantitative RT-PCR and Western blot assay.The eukaryotic expression vectors of the vapB and vapC genes were generated for transfection of host cells and CCK-8 agent was used to detect the effect of leptospiral VapB and VapC proteins on activity of host cells.Results The nucleotide and putative amino acid sequences of the cloned vapB and vapC genes were completely identical with the reported corresponding genes.The constructed prokaryotic expression systems could express rVapB and rVapC,respectively.rVapC displayed RNase avtivity but did not lyse DNA.When L.interrogans strain Lai infected THP-1 cells,the transcription and expression of vapB and vapC genes were upregulated and partial VapC protein was secreted from the leptospiral cells.The mass mortality was observed in HEK293 human renal tubular epithelial ceils containing the vapC gene through transfection.Conclusion VapC protein of L.interrogans strain Lai is a RNase and is secreted during infection of host cells with obvious cytotoxicity.
7.Comparison of loop-mediated isothermal amplification and real-time PCR for the detection of Leptospira interrogans
Bao FANG ; Shibiao DING ; Jie YAN ; Xuai LIN
Chinese Journal of Microbiology and Immunology 2011;31(8):751-754
Objective To compare the sensitivity and specificity of Leptospira interrogans using loop-mediated isothermal amplification (LAMP) and real-time PCR technology, then looking for a rapid,sensitive and specific methods for the detection of Leptospira interrogans. MethodsIn accordance with lipL41 gene from Leptospira interrogans, primers for LAMP and real-time PCR were designed and used to detect Leptospira interrogans in cultured 15 reference strains of 15 serogroups in China, then compared the sensitivity and specificity of the two methods in the detection of Leptospira interrogans. ResultsThe LAMP reaction could be completed within 30 min, and whole process of it less than 60 min. The whole real-time PCR reaction could be finished at about 60 min. Both of them had the same detection sensitivity and specificity,the lower detection limits in the reactions was approximately 100 copies and there was no false positive occurred. ConclusionBoth LAMP and real-time PCR were time-saving and had the same sensitivity and specificity. But LAMP reaction could be done under a constant temperature conditions, and need not a special expensive equipment. Therefore, as a sensitive and specific method for quantifying Leptospira interrogans,the LAMP assay was more rapidly and convenient than conventional methods.
8.Expression of T and B cells combined epitopes protein of Leptospira interrogans and the immunity analysis
Shibiao DING ; Zhaodong LI ; Jie YAN ; Xuai LIN
Chinese Journal of Microbiology and Immunology 2011;31(10):938-941
Objective To construct the T-cells and B-cells combined epitope peptide gene based on the LipL32,OmpL1 and LipL21 protein from Leptospira interrogans and E.coli expression system,and better understanding of the immunological activity of the recombinant protein. MethodsThe immunodomaint T- and B-cells combined epitopes of LipL32,OmpL1 and LipL21 were identified and used to synthetic a new gene and then construct its prokaryotic expression system.The expression of recombinant protein was determined by SDS-PAGE; MAT was used to determine the titer of the antiserum to L. interrogans standard strains of China ; Western blot and ELISA were used to identify the immunity activity of the recombinant protein.Results The synthetic gene was effectively expressed in E.coli BL21 ( DE3 ) strain and mainly presented in dissoluble protein.Western blot result showed that the expression protein react well with the antibodies from immunized rabbit by Leptospira or recombinant protein.ELISA and MAT results showed that the multiepitope protein could cross-react with different serogroup or serovar of Leptospira.Conclusion In this study,we successfully constructed the recombinant T- and B-cells combine epitope gene of leptospires and expressed it in E.coli.The recombinant protein had a good immune activity,and could cross-reacted with antibodies from different serogroups Leptospira infected patients.
9.Study on the Effect of Dark Tea Fermentation Liquid with Eurotium cristatum on the Activity of Digestive Enzyme
Qun HUANG ; Lin-Jie CHEN ; Yan-Po LI ; Ke CHE ;
Microbiology 1992;0(05):-
The effect of dark tea fermentation liquid with Eurotium Cristatum on the activity of digestive enzyme was researched, as fellowing amylase, protease, lipase. The results showed that dark tea fermentation liquid with Eurotium Cristatum may increase remarkably the activity of ?-amylase and protease, but decrease efficiently the activity of lipase. The fermentation liquid improves the digestion and absorption of starch and protein, but inhibits the decomposition and absorption of fat, so it can explain the mechanism of Fu-brick tea's health functions.
10.Necessity and assumption of hospital scientific research fund management platform
Yan WANG ; Zhiyun LIU ; Yun ZHANG ; Jie WU ; Lin ZHU
Chinese Journal of Medical Science Research Management 2017;30(2):116-117,121
Objective Build the hospital scientific research management platform.Methods According to expenditure process and the management standard requirements,the establishment of a fund management system platform to achieve budget、accounted for,spending and audit feedback function.Results Scientific research funds management platform is mainly composed of project application,project establishment and review,the report query and remittance receipt of financial department.Full consideration of the personnel,project,financial and other related system interface.In the construction of data using the standards of the state and the university scientific research information.Conclusions Through building the hospital scientific research management platform,improving the working efficiency,reducing the labor intensity of the management and financial personnel,realizing the accuracy and effectiveness of management.