Objective To clone mcp1, mcp2 and mop3 genes that encoding methyl-accepting chemotaxis proteins(MCP) of Campy/obacter jejuni for construction of their prokaryotic expression systems, and to establish chemotactic model in vitro of the microbe for determining chemotaxis-inducing substances and to understand relationship among MCPs and chemotactic inducers. Methods The segments of mep1, mcp2 and mcp3 genes were amplified by PCR and then sequenced after T-A cloning. Prokaryofic expression systems of the genes were subsequently constructed. SDS-PAGE pins Bin-Rod Gel Image Analyzer were used to examine the expression of target recombinant proteins rMCP1, rMCP2 and rMCP3, and Ni-NTA affinity chromatography was performed to purify the rMCPs. Rabbits were immunized with each of the three rMCPs to obtain antisera. Immunodiffusion assay was performed to measure the titers of antisera. IgG in each of the antisera were extracted by ammonium sulfate precipitation and DEAE-32 ion exchange chromatography, and IgG F(ab')2 were then prepared by pepsin enzymolysis and Sephadex G-100 chromatography. Chemotactic model in vitro of C. jejuni based on HAP( hard-agar plus) method was established to determine the chemo-taxis-inducing effect of eight candidate substances. Chemotaxis inhibition test based on IgG F(ab')2 bloc-king was applied to determine the function and diversity of MCPs. Results The segments with expected si-zes amplified from mcp1, racp2 and mcp3 genes were obtained by PCRs, and their nucleotide and putative amino acid sequences were completely same as the reported. The constructed prokaryotic systems could effi-ciently express rMCPs with the yields about 10% of the total bacterial proteins. Immunization with rMCP1, MCP2 and rMCP3 enables the rabbits to produce specific antibody. All the antisera had 1: 4 immunodiffusion titers. Both bovine bile and sodium deoxycholate(DOC) were able to induce ehemotactie movement of C. je-juni in a dosage-dependent manner ( P < 0.05 ). When MCP1 and MCP2 were blocked with their IgG F(ab')2, the ehemotaetic ability of C. jejurd were remarkably decreased (P <0. 05). However, MCP3 blocking did not affect the chemotaxis ( P > 0.05 ). Conclusion The C. jejuni MCPs are successfully ex-pressed in this study. Bovine bile and DOC are the inducers for chemotaxis of C. jejuni, and MCP1 and MCP2 are involved in the process of ehemotaxis iadueed by DOC.

Objective To investigate the function of phosphatidylinositol phospholipase C encoded by LB361 gene of L.interrogans ( L-PI-PLC) and its mechanism in inducing macrophage apoptosis .Meth-ods The PI-PLC domains in the sequence of LB 361 gene of L.interrogans serovar Lai strain were analyzed by bioinformatics method .Prokaryotic expression system was established to express the recombinant L -PI-PLC ( rL-PI -PLC).The enzymatic activity of rL-PI-PLC in hydrolyzing phosphatidylinositol -4,5-bisphos -phate (PIP2) substrate into inositol-1,4,5-trisphosphate (IP3) was determined by IP3 fluorescence polariza-tion assay.LB361gene expressions at mRNA and protein levels as well as the secretion of LB 361gene prod -ucts were detected by real-time fluorescent quantitative RT -PCR and Western blot assay after infection of hu-man THP-1 macrophages with L.interrogans serovar Lai strain.A LB361 gene-transfected THP -1cell line was generated for evaluation of the mechanism of LB 361 gene products in elevating intracellular free Ca 2+( [Ca 2+] i) concentration and inducing the apoptosis of transfected THP -1 cells with the use of laser confocal microscopy and flow cytometry.Re sul ts The rL-PI-PLC hydrolyzed PIP2 into IP3 with a Km of 199 μmol/L and a Kcat of 8.566×10-5 S-1 .The expressions of LB361gene at mRNA and protein levels were both signifi -cantly up-regulated after infection of THP-1 cells with L.interrogans serovar Lai strain .Moreover , the exter-nal secretion of L-PI-PLC was also found during infection .The concentrations of IP 3 and [ Ca2+] i in the LB361 gene-transfected THP-1 cells were significantly increased compared to those in the non-transfected THP-1 cells, resulting in a high [Ca2+]i-dependent apoptosis of partial THP-1 cells.Conclusion PI-PLC is encoded by the LB361 gene of L.interrogans, which could induce the apoptosis of macrophages through el-evating [ Ca2+] i concentration during infection of microphages with L.interrogans.

OBJECTIVETo construct a knockout fliY gene mutant strain of Campylobacter jejuni for determining the role of FliY protein in flagellar movement related to bacterial motility, chemotaxis and colonization.

METHODSThe plasmid pBluescript-II-SK was used to construct the suicide plasmid; according to homologous exchange principle, the suicide plasmid was utilized to generate fliY gene knockout mutant(fliY) in Campylobacter jejuni strain NCTC11168. The fliY mutant strain was identified by PCR, sequencing and Western blotting. The chemotactic and colonizing abilities of fliY mutant were determined by colony migration test and bacterial chemotactic test in vitro, and colonization test in jejunum of mice.

RESULTSThe fliY(-)mutant strain showed a growth curve in medium similar to that of wild-type strain. PCR, sequencing and Western blotting assay confirmed that the fliY gene in fliY(-)mutant was deleted. Compared to the wild-type strain, the colonies of fliY-mutant on semisolid plate were much smaller (P <0.05), the chemotactic ability of fliY mutant towards sodium deoxycholate and bovine bile was significantly attenuated (P <0.05), and the number of fliY mutant (CFU) in jejunal tissue specimens of the infected mice was significantly decreased (P<0.05).

CONCLUSIONThe function of C.jejuni fliY gene refers to controlling flagellar movement, which is involved in bacterial chemotaxis and colonization.

Animals ; Bacterial Proteins ; genetics ; Campylobacter jejuni ; genetics ; pathogenicity ; Chemotaxis ; genetics ; Gene Knockout Techniques ; Jejunum ; microbiology ; Membrane Proteins ; genetics ; Mice ; Mice, Inbred BALB C

Sepsis and septic shock have high morbidity and mortality. The key point is that huge amount of nitric oxide (NO) is releasing into circulation, inducing marked dilation of blood vessels, and continuously decreased of blood pressure. The central link is inflammation and oxidative stress. Methylene blue can effectively inhibit NO, remove excessive NO and block the signal transduction pathway named inducible nitric oxide synthase-NO-soluble guanylate cyclase-cyclic guanosine monophosphate (iNOS-NO-sGC-cGMP). Meanwhile, it also play a role in inhibiting oxidative stress and inflammation. This paper reviews the mechanism of methylene blue in the treatment of sepsis and septic shock, as well as its treatment time window, optimal dose, administration mode and potential adverse reactions, to provide new ideas for clinical treatment.

OBJECTIVE To identify, synthesize and analyze the structure of unknown impurities unique to bromhexine hydrochloride injection and set the impurities as known impurity to control. METHODS The structure of unknown impurities was derived through two-dimensional liquid chromatography tandem mass spectrometry(2DLC-HRMS/MS), and the source of impurities was derived based on the product's prescription process. The mechanism of impurities generation was analyzed, and impurity monomers were obtained through directional synthesis. The structure of impurities was confirmed using techniques such as 2DLC-HRMS/MS and nuclear magnetic resonance. Finally, HPLC was used to verify the analysis method of impurities. RESULTS It was confirmed that such impurities were produced in a reaction between bromhexine and the excipient glucose. The correction factor of the two impurities were 2.2 and 2.4, the analytical method was specific and reproducible. CONCLUSION Name the two injection specific impurities as impurity 1 and impurity 2 respectively, and use them as known impurities to be included in the standard, calculate the impurity content using the self control and correction factor method. This study is of great significance in guiding the impurity control of bromhexine hydrochloride injection and the screening of excipient glucose.