Objective A prokaryotic expression vector was constructed by inserting the coding sequence of mouse sperm specific lactate dehydrogenase C into pET-28a(+)and the recombinant mLDHC44 protein was purified by Ni+-NTA agrose.Methods The cDNA of mouse sperm specific lactate dehydrogenase C was obtained by RT-PCR,with total RNA of mouse testis tissues as templates.The coding sequence of mouse LDHC4 was amplified by PCR with specific primers.This recombinant vector was transformed into Escherichia coli BL21(DE3).The recombinant mLDHC4 protein was induced by isopropy-?-D-thiogalactoside(IPTG)and identified by sodium dodecyl sulfate polyacrylamide electrophoresis and LDH activity determination.After purified with Ni+-NTA agrose,the mLDHC4 protein was probed with antisera from the pVAX1-mLDHC4 vaccine(the eukaryotic expression vector of mouse sperm specific lactate dehydrogenase C)immunized BALB/c mice by Western blot analysis.Results After digested with BamH I-EcoR I,the recombinant plasmids produced right fragment which was about 1000bp.Sequencing showed that the sequence of the cloned fragment was in agreement with sequence in GenBank.This recombinant vector was named as pET-28a(+)-mLDHC4.With induction of IPTG,The recombinant protein with molecular weight of about 35 kD was expressed and the enzyme activity of this protein was high.After purified with Ni+-NTA agrose,this mLDHC4 protein formed a specific band by sodium dodecyl sulfate polyacrylamide electrophoresis and probed with antisera from immunized BALB/c mice and then formed a specific band in the nitrocellulose membrane.Conclusion The coding sequence of mouse lactate dehydrogenase subunit C had been cloned into the prokaryotic expression vector pET-28a(+)and the mLDHC4 protein could be expressed at a high level,the specificity of this protein was high and the activity was strong.

OBJECTIVESTo construct a prokaryotic recombinant vector for mouse lactate dehydrogenase-C and to detect its expression in BL21.

METHODSThe coding sequence of mouse lactate dehydrogenase subunit C was amplified from mouse testis RNA with specific primers, and cloned into pGEX-2T after the restriction digestion with BamH I and EcoR I. GST fusion protein was expressed after induction with IPTG.

RESULTSSequencing and restriction digestion of the recombinant plasmid revealed the existence of coding sequence for mouse lactate dehydrogenase subunit C. A protein band of about 60,000 could be induced by IPTG in the recombinant plasmid.

CONCLUSIONSThe coding sequence of mouse lactate dehydrogenase subunit C was introduced into the pGEX-2T plasmid and a GST-fused protein could be induced at a high level.

Animals ; Escherichia coli ; genetics ; Glutathione Transferase ; genetics ; Isoenzymes ; genetics ; L-Lactate Dehydrogenase ; genetics ; Male ; Mice ; Recombinant Fusion Proteins ; biosynthesis ; Spermatozoa ; enzymology

Objective To investigate distribution and antimicrobial resistance among nosocomial pathogens from 13 teaching hospitals in China in 2009. Methods Non-repetitive pathogens from nosocomial BSI, HAP and IAI were collected and sent to the central lab for MIC determination by agar dilution method.WHONET5.6 software was used to analyze the data. Results A total of 2 502 clinical isolates were collected. The top three pathogens of BSI were Escherichia coli [27. 1% (285/1 052 )] , coagulase-negutive staphylococcus [12. 6% ( 133/1 052)] and Klebsiella pneumoniae [10. 8% ( 114/1 052)]. The top three pathogens of HAP were Acinetobacter baumannii [28. 8% (226/785)], Pseudomonas aeruginosa [16. 1% (126/785)] and Klebsiella pneumoniae [14.6% (115/785 )] . The top three pathogens of IAI were Escherichia coli[31.0% ( 206/665 )], Klebsiella pneumonia [11.3% ( 75/665 )] and Enterococcus faecium [10. 8% (72/665)]. Against Escherichia coil and Klebsiella spp. , the antimicrobial agents with higher than 80% susceptibility rate included imipenem and meropenem (98. 1%-100% ), tigecycline (95.3%-100% ), piperacillin-tazobactam ( 88.6% -97. 1% ) and amikacin ( 88. 3% -92. 5% ). Against Enterobacter spp. , Citrobacter spp. and Serratia spp. , the susceptibility rates of tigecycline were 93.5% -100% whereas the value of imipenem and meropenem were 92.9% -100%. Other antimicrobial agents with high activity included amikacin ( 85.2% -96. 7% ), pipcracillin-tazobactam ( 82.4% -96.4% ), cefepime ( 79. 6% -96. 7% ) and cefoperazonc-sulbactam (78. 7%-90. 0% ). Polymyxin B showed the highest susceptibility rateagainst Pseudomonas aeruginosa ( 100% ), followed by amikacin ( 81.9% ) and piperacillin-tazobactam (80.1% ). Polymyxin B also showed the highest susceptibility rate against Acinetobacter baumannii (98. 8% ), followed by tigecycline (90. 1% ) and minocycline (72. 0% ). The incidence of carbapenemresistant Acinetobacter baumannii was 60. 1%. The MRSA rate was 60. 2% and the MRSCoN rate was 84. 2%. All Staphylococcus strains were susceptible to tigecycline, vancomycin, teicoplanin and linezolid except for one isolate of Staphylococcus haemolysis with intermediate to teicoplanin. Two Enterococcus faecalis isolates which were intermediate to linezolid and one Enterococcus faecium isolate which was resistant to vancomycin and teicoplanin was found in this surveillance, while the MICs of tigecycline against these three isolates were 0. 032-0. 064 μg/ml. Conclusions Tigecycline, carbapenems, piperacillin-tazobactam,amikacin and cefepime remain relatively high activity against nosocomial Enterobacteriaceae. Pseudomonas aeruginosa exhibite high susceptibility to polymyxin B, while Acinetobacter baumanni shows high susceptibility to polymyxin B and tigecycline. Tigecycline, vancomycin, teicoplanin and linezolid remain high activity against nosocomial gram-positive cocci.