Objective To investigate the possible mechanism of metoprolol on protecting against ischemia‐reperfusion in‐duced injury .Methods A total of 32 healthy 3-4 months male C57BL/6 mice were divided into four groups(n=8)as following :Sham‐operating group(control group);metoprolol group;ischemia‐reperfusion group(I/R group);metoprolol + I/R group .Myo‐cardial injury ,apoptosis ,cytochrome c release ,Caspase‐3 activity and calpain activity were determined in these groups .Results Al‐though there was no obvious changes in the regions at risk between I/R group and metoprolol + I/R group ,metoprolol pretreat‐ment significantly reduced the ratio of the infarct to risk regions(P<0 .05) .In the I/R group ,the rate of cardiomyocyte apoptosis , cytochrome c release ,as well as the activity of Caspase‐3 and calpain significantly increased compared to the control group(P<0 .01) .However ,these effects of I/R injury were alleviated by pretreatment with metoprolol .Conclusion metoprolol might protect against ischemia‐reperfusion induced injury by preventing calpain activation .

Objective To investigate the epidemiological and pathogenic characteristics of viral diarrhea in Minhang District, Shanghai. Methods Random sampling on diarrhea was conducted in intestinal outpatient departments of 2 sentinel hospitals according to a certain sampling interval in Minhang District，Shanghai from 2014 to 2020. Real time PCR technology was used to detect Rotavirus, Norovirus, adenovirus, Astrovirus and Sapovirus in fecal samples. Results A total of 646 out of 1 839 stool specimenswere tested positive, and the positive rate was 35.13%.Five pathogenic viruses were detected , mostly norovirus (421 cases, 65.17%) followed by rotavirus (151 cases, 23.37%).The positive rate of norovirus was higher in the age group of 20- 69 years, and the positive rate of Rotavirus was higher in the age group of 0- 9 years. Conclusions Norovirus and rotavirus accounted for the majority of reported infection diarrhea cases in MinhangDistrict of Shanghai from 2014 to 2020, with significant seasonal peaks. Tailored prevention and control measures should be carried out, particularly in risk seasons.

In order to overcome the challenges of insufficient restriction enzyme sites, and construct a fusion-expression vector with flexible fusion direction, we designed an LB cloning system based on the type IIS and type IIT restriction enzymes LguⅠ and BbvCⅠ. The LB cloning system is constructed by inserting the LB fragment (GCTCTTCCTCAGC) into the multiple cloning site region of the broad-host plasmid pBBR1MCS-3 using PCR. The LB fragment contains partially overlapped recognition sites of LguⅠ and BbvCⅠ. Therefore, the same non-palindromic sequence will be generated by these two restriction endonucleases digestion. This feature can be used to quickly and flexibly insert multiple genes into the expression vector in a stepwise and directed way. In order to verify the efficacy of the cloning system, two glycosyltransferase genes welB and welK of Sphingomonas sp. WG were consecutively fused to the LB cloning vector, and the recombinant plasmid was transferred into Sphingomonas sp. WG by triparental mating. The results showed that gene fusion expression has little effect on sphingan titer, but enhanced the viscosity of sphingan. The viscosity of the sphingan produced by recombinant strain Sphingomonas sp. WG/pBBR1MCS-3-LB-welKB was 24.7% higher than that of the wild strain after fermentation for 84 h, which would be beneficial for its application. In conclusion, the application of LB cloning system were verified using Sphingomonas sp. WG. The LB cloning system may provide an efficient tool for fusion expression of target genes.
Base Sequence ; Cloning, Molecular ; Fermentation ; Plasmids/genetics* ; Sphingomonas/metabolism*