The Y118A、Y118F、Y118T、S378A、S378T、H310A、H310R mutants of Candida albicans sterol 14?-demethylase (CACYP51) were constructed and heterologously expressed in D12667, the reconstructed strain with the deletion of CYP51 gene of the Y12667. With the strains obtained and microsome enzymes separated, the western blot and the ultraviolet absorption spectrophotometry were used to qualitative and quantitative detect the expressed protein, the GC-MS was used to detect the metabolism activity of the protein. The results showed that, the target protein expressed successfully in the reconstructed strains, with the expression level up to 25% of the total microsome proteins. The results also showed that, the wild type protein had the catalytic activity to its nature substrate. While after alteration the wild gene with Y118A、Y118F、Y118T、S378A、S378T、H310A、H310R by a single base substitution, the catalytic activity of protein markedly decreased respectively. So the wild type and mutation CYP51 were expressed successfully in Saccharomyces cerevisiae and the expression products preserved the activity to metabolism their nature substrate.

In this paper, we analyze the status of the medical device testing and the situation of the unqualifie varieties by sorting out the situation of the national medical device supervision and inspection from 2013 to 2016. We analyze the results of the inspection deeply, and find that the safety risk points exists in the quality of the medical device testing products and management system, product technology requirements, the national standards, industry standards or other aspects, then explain one by one with typical examples. At the same time the corresponding suggestions are put forward to production companies and regulators respectively on the existing problems.

Objective To explore the prognostic value of serum neutrophils/lymphocytes(NLR)for first-line treatment of patients with advanced gastric cancer using programmed cell death receptor 1(PD-1)inhibitors.Methods A total of 168 patients with advanced gastric cancer who were treated with immunotherapy combined with chemotherapy in the Fourth Hospital of Qinhuangdao from January 2018 to January 2021 were selected as study subjects,and the follow-up period was terminated at January 2023.The patients'data were collected,hematological and tumor markers before the combined treatment were analyzed,and the optimal cut-off value of NLR was calculated using X-tile software.The effect of NLR expression on the survival rate of patients with advanced gastric cancer was analysed by the Kaplan-Meier survival curve.Receiver operating curve(ROC)was used to analyze the predictive value of NLR in patients with advanced gastric cancer.The related factors affecting the disease progression of patients with advanced gastric cancer were screened combined with Cox proportional risk model.Results Among 168 patients,the optimal cut-off value of serum NLR before treatment was 2.41.Patients were divided into high NLR group(NLR＞2.41,n=93)and low NLR group(NLR＜2.41,n=75).NLR was related to tumor differentiation,distant metastasis,composite positive scores of PD-L1,carcinoembryonic antigen and cancer antigen 125(P＜0.05);the effective rate in the low NLR group was significantly higher than that in the high NLR group(P＜0.05);the median progression free survival(PFS)and the overall survival(OS)of patients in the low NLR group were both longer than those in the high NLR group(PFS:P=0.006;OS:P=0.023);ROC analysis showed that the area under the curve of NLR for the prognosis of advanced gastric cancer patients was 0.740,sensitivity was 81.50％,and specificity was 69.70％;in multivariate analysis,except initial NLR value,tumor differentiation degree and distant metastasis were also independent predictors of poor prognosis in patients with advanced gastric cancer(P＜0.05).Conclusion Among patients with advanced gastric cancer who received first-line immunotherapy combined with chemotherapy,pretreatment NLR is correlated with efficacy and PFS/OS,and has high value in predicting the prognosis of immunotherapy for advanced gastric cancer.