Aim To explore the effect of Cx43 over-expression on proliferation of C6 cells and its mechanisms by transfecting pCMV-Cx43cDNA plasmid into C6 cells.Methods pCMV-Cx43cDNA plasmid was transfected into C6 cells by liposome to up-regulate the expression of Cx43, and C6 cells with over-expression of Cx43 was stably cloned by using G418.Determination of cell doubling time and soft agar colony formation assay to detect the degree of cell proliferation.The cells were treated with ERK1/2 specific blocker PD98059(30 μmol·L-1) and p38MAPK specific blocker SB202190(10 μmol·L-1)respectively, the expression of Cx43, p-Cx43, p-ERK1/2 and p-p38MAPK of each group were detected by Western blot, and the activity of each group was detected by MTT Assay.Results pCMV-Cx43cDNA plasmid was transfected into C6 cells successfully.Cell lines with over-expression Cx43(C6-Cx43) or empty vector (C6-pCMV) were stably selected by using G418.Determination of cell doubling time and soft agar colony formation experiments showed that the proliferative rate and the colony number of C6-Cx43 group were significantly decreased, compared with that of C6 group and C6-pCMV group(P<0.01);ERK1/2, p38MAPK specific blockers were treated with each group,Western blot showed that the expression of Cx43 protein was increased(P<0.01), while p-Cx43 protein was decreased (P<0.05) in C6-Cx43+PD98059 group and C6-Cx43+SB202190 group,compared with that of C6-Cx43 group.Conclusion Cx43 may decrease the proliferation of glioma cells through ERK1/2, p38MAPK pathways.

A high performance liquid chromatography tandem mass spectrometric ( HPLC-MS/MS ) method was developed for the determination of seven perfluorinated alkyl acidin ( C4-C10 ) and perfluorooctane sulfonate in water. After the particulate was removed by leaching, surrogate standard was added, then the sample was loading to a pre-conditioned WAX cartridge for purification, and then the eluent was concentrated and analyzed by HPLC-MS/MS. Due to the situation that the fluoride polymer was unavoidable to be used in the LC system, a delay column was employed and the perfluorooctanoic acid ( PFOA ) of interference was departed from the PFOA in sample. The method detection limit ( MDL) of PFOA was 0. 8 ng/L, and the lowest quantitative concentration (LQC) was 3. 2 ng/L. For other compounds, the MDL was ranged from 0. 2 to 1. 2 ng/L, and the LQC was 0. 8-4. 8 ng/L. This method also had good reproducibility, for six duplicated samples, the relative standard deviations ( RSD ) of all target compounds were less than 16%. And the recoveries of target compounds at six spiked matrix samples ranged from 87% to 129%, and the RSD were less than 15%. Because of the connection of delay column, the background was well controlled, and a relatively lower MDL were obtained.

OBJECTIVETo elucidate the epidemic condition and molecular subtyping of ciprofloxacin and cefotaxime co-resistant Salmonella Indiana (S. Indiana) isolated from retail chicken carcasses in six provinces of China.

METHODSA total of 2 647 Salmonella strains isolated from retail chicken carcasses collected from six provinces of China were subjected to antimicrobial susceptibility testing. All Salmonella isolates co-resistant to ciprofloxacin and cefotaxime were further characterized by serotyping, extended-spectrum beta-lactamases (ESBLs) producing strains screening and pulsed field gel electrophoresis (PFGE) typing.

RESULTSAmong 2 629 Salmonella isolates tested, 227 (8.52%) isolates were co-resistant to ciprofloxacin and ceftazidime/cefotaxime (Beijing: 11.67% (99/874), Jilin: 8.20% (60/726), Guangdong: 1.39% (7/502), Jiangsu: 15.61% (42/260), Shaanxi: 8.56% (16/186), Inner Mongolia: 0 (0/81)), and 224 of them were identified as S. Indiana. 213 (95.10%) isolates of S. Indiana were ESBLs producing strains. All ciprofloxacin and cefotaxime co-resistant S. Indiana isolates developed a multi-drug resistant profile and 17.86% (40/224) of them were resistant to all antibiotics tested except carbapenems, and 50.89% (114/224) of them resistant to 9 antibiotics, additionally, 25.45% (57/224) of them showed multi-drug resistance to 8 antibiotics. All ciprofloxacin and cefotaxime co-resistant S. Indiana isolates were divided into 32 PFGE clusters and 150 PFGE patterns. Strains of S. Indiana from same or different sampling site and time seemed to either share the same PFGE patterns or be differential to each other in different regions.

CONCLUSIONThe results indicated that chicken carcasses collected from parts of China were heavily contaminated by ciprofloxacin and cefotaxime co-resistant S. Indiana and could serve as an important reservoir of ciprofloxacin and cefotaxime co-resistant Salmonella. Molecular subtyping results indicated that cross contamination or common pollution source might be in these strains.

Animals ; Anti-Bacterial Agents ; pharmacology ; Cefotaxime ; pharmacology ; Chickens ; microbiology ; China ; Ciprofloxacin ; pharmacology ; Drug Resistance, Multiple, Bacterial ; Electrophoresis, Gel, Pulsed-Field ; Food Contamination ; Food Microbiology ; Meat ; microbiology ; Salmonella ; classification ; isolation & purification ; Serotyping ; beta-Lactamases

Objective: To obtain the serotype diversity and antimicrobial resistance of Salmonella isolates recovered from retail chicken carcasses for sale in six regions of China. Methods: From August 2010 to March 2012, each month 20 retail chicken carcasses including freshly slaughtered, chilled and frozen samples were collected from supermarkets and farmer's markets in 7 monitoring sites in Beijing, Jilin province, Inner Mongolia Autonomous, Shanxi province, Jiangsu province and Guangdong province, respectively. Samples were routinely collected for 12 months for each site. 1 680 chicken carcasses were collected in total and 2 629 Salmonella strains were isolated by PCR and biochemical method. Luminex xMAP method and classical slide agglutination method were carried out to determine isolates' serotypes. Minimal inhibitory concentrations (MICs) of 10 classes of antimicrobials including 14 agents were determined using broth micro-dilution method. Mocular methods were used to determine antimicrobial resistance genes of CIP-CTX-CT co-resistant isolates. Results: In all, 2 629 Salmonella isolates, there were 17 seorgroups and 58 serotypes, B and D1 were the dominant serogroups with rates of 34.7% (n=913) and 31.0% (n=815), Enteritidis (30.8%, n=810), Indiana (17.6%, n=463), Infantis (10.6%, n=278) were the top three serovars. We found 224 CIP-CTX co-resistant S. Indiana containing 3 colistin resistant strains, one of them carrying mcr-1 gene and being ESBLs positive, which demonstrated a nine multi drug resistance against 11 antimicrobials tested. Conclusion These data began to describe the complicated serovar diversity and heavy antimicrobial resistance of Salmonella isolates recovered from retail chicken carcasses in six regions of China. The findings highlight the emergence of ciprofloxacin and cefotaxime co-resistant S. Indiana and also a mcr-1 positive S. Indiana with heavy multi drug resistance.