Research progress on antibiotic resistance of Escherichia coli O157:H7 / 预防医学

@#Contamination of foodborne pathogens is the main cause of related diseases. Escherichia coli O157:H7 (E.coli O157:H7), as a representative of pathogenic E.coli, is one of the most severe and commonly reported E.coli in the world, but there is still no effective clinical treatment against the infection. Antibiotics show effective in the early infection of E.coli O157:H7. However, their extensive use has led to drug-resistant bacteria and genes in recent years, which becomes a great threat to public health. This article reviews the research progress of E.coli O157:H7 from the prevalence of antibiotic-resistant bacteria, the resistance mechanism, and the prevention and control methods, in order to provide a reference for its prevention, early clinical treatment and related research.

Establishment of pancreatic mucinous cystadenocarcinoma cell line MCC1 with stable overexpression of miR-224 / 中国肿瘤生物治疗杂志

@#Objective: To construct a hsa-microRNA-224(miR-224) lentiviral expression vector and to establish pancreatic mucinous cystadenocarcinoma MCC1 cell line with stable miR-224 over-expression. Methods: Pri-miR-224 gene fragment was designed and amplified by quantitative real-time polymerase chain reaction (qRT-PCR), and then loaded into GV369 lentiviral vectors (GV369-miR224) by gene recombination technology. GV369-miR-224 lentivrial expression vectors were then identified by PCR and DNA sequencing. The GV369-miR-224 vector fluid was then used to infect pancreatic mucinous cystadenocarcinoma MCC1 cell line to establish the MCC1 cell line stably over-expressing miR-224. The transfection efficiency of GV369-NC and GV369-miR-224 was observed under fluorescence microscopy; and the expression levels of miR-224 in MCC1, GV369-miR-224-MCC1 and GV369-NC-MCC1 cell lines were detected by RT-PCR. Results: The GV369-miR-224 lentiviral vectors were successfully constructed. GV369-miR-224-MCC1 and GV369-NC-MCC1 cells all emit green fluorescence under the fluorescence microscope. The expression level of miR-224 in GV369miR-224-MCC1 cell group was significantly higher than that in negative control GV369-miR-224-MCC1 group and blank control MCC1 cell group (23.45±1.94， 1.46±0.1 and 2.11±0.38, P<0.01), however, there was no significant difference between the two control groups (P>0.05). Conclusion: A pancreatic mucinous cystadenocarcinoma MCC1 cell line with stable miR-224 over-expression was successfully established, and this will provide a new cell model for exploring the function and pathogenesis of miR-224 in pancreatic mucinous cystadenocarcinoma.