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        Fermentation Optimization and Industrialization of Recombinant Saccharopolyspora erythraea Strains for Improved Erythromycin A Production

        Xiang Zou,Chang-fa Chen,Xia-chang Qi,Jiang-chao Qian,Ju Chu,Ying-ping Zhuang,Si-liang Zhang,Wei Zeng,Wan-jun Li 한국생물공학회 2010 Biotechnology and Bioprocess Engineering Vol.15 No.6

        Improvement of Erythromycin A (Er-A) production and purity by metabolic engineering of the industrial erythromycin-producing strains Saccharopolyspora erythraea strians ZL1004 and ZL1007, in which the amounts of tailoring enzymes EryK (a P450 hydroxylase)and EryG (an S-adenosylmethionine-dependent O-methyltransferase)for biotransformation of Erythromycin D to Er-A were modulated, was performed in a 50 L fermentor. Addition of 15 g/L of corn steep liquor to the medium increased Er-A production; maximum Er-A production was 8,196 U/mL at 191 h, which was 81.8% higher than that of control (4,507 U/mL at 184 h). Er-B impurities were completely eliminated, whereas Er-C impurities were only 153 U/mL at 191 h. Analysis of intra- and extracellular metabolites and key enzyme activities in central carbon metabolism revealed that the pool of TCA cycle intermediates was enhanced by the addition of corn steep liquor and induced an increase in erythromycin biosynthesis. There were no significant differences between strains ZL1004 and ZL1007 regarding Er-A production and impurity accumulation. Compared to wild type strain,Er-A production was improved by 23.9% while Er-C was reduced by 83.9% and Er-B was completely eliminated. Furthermore, fermentation of recombinant strain ZL1004was successfully scaled up from laboratory scale (50 L fermentor) to industrial scale (25 and 132 m3), with similar levels of Er-A production and purity obtained.

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        Sitagliptin attenuates endothelial dysfunction independent of its blood glucose controlling effect

        Xin-Miao Chang,Fei Xiao,Qi Pan,Xiao-Xia Wang,Li-Xin Guo 대한생리학회-대한약리학회 2021 The Korean Journal of Physiology & Pharmacology Vol.25 No.5

        Although the contributions of sitagliptin to endothelial dysfunction in diabetes mellitus were previously reported, the mechanisms still undefined. Autophagy plays an important role in the development of diabetes mellitus, but its role in diabetic macrovascular complications is unclear. This study aims to observe the effect of sitagliptin on macrovascular endothelium in diabetes and explore the role of autophagy in this process. Diabetic rats were induced through administration of high-fat diet and intraperitoneal injection of streptozotocin. Then diabetic rats were treated with or without sitagliptin for 12 weeks. Endothelial damage and autophagy were measured. Human umbilical vein endothelial cells were cultured either in normal glucose or in high glucose medium and intervened with different concentrations of sitagliptin. Rapamycin was used to induce autophagy. Cell viability, apoptosis and autophagy were detected. The expressions of proteins in c-Jun N-terminal kinase (JNK)-Bcl-2-Beclin-1 pathway were measured. Sitagliptin attenuated injuries of endothelium in vivo and in vitro. The expression of microtubuleassociated protein 1 light chain 3 II (LC3II) and beclin-1 were increased in aortas of diabetic rats and cells cultured with high-glucose, while sitagliptin inhibited the over-expression of LC3II and beclin-1. In vitro pre-treatment with sitagliptin decreased rapamycin-induced autophagy. However, after pretreatment with rapamycin, the protective effect of sitagliptin on endothelial cells was abolished. Further studies revealed sitagliptin increased the expression of Bcl-2, while inhibited the expression of JNK in vivo. Sitagliptin attenuates injuries of vascular endothelial cells caused by high glucose through inhibiting over-activated autophagy. JNK-Bcl-2-Beclin-1 pathway may be involved in this process.

      • Knowledge of Human Papillomavirus (HPV) Infection, Cervical Cancer, and HPV Vaccine and its Correlates among Medical Students in Southwest China: a Multi-center Cross-sectional Survey

        Wen, Ying,Pan, Xiong-Fei,Zhao, Zhi-Mei,Chen, Feng,Fu, Chun-Jing,Li, Si-Qi,Zhao, Yun,Chang, Hong,Xue, Qing-Ping,Yang, Chun-Xia Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.14

        Background: Since cervical cancer can be prevented and controlled through human papillomavirus (HPV) vaccination, it is important to train health care providers and provide them with appropriate knowledge. This study aimed to understand the level of HPV related knowledge among medical students and correlates in Southwest China in order to address any potential gap in their knowledge base. Methods: We conducted a cross-sectional survey among medical students in six selected universities across Southwest China based on a pretested questionnaire regarding HPV infection, cervical cancer, and HPV vaccines. Results: We successfully surveyed 1, 878 medical students, of whom 32.1% were males and 67.9% were females. Their mean age was 20.8 (standard deviation: 1.3) years. 91.8% of them were ethnic Han Chinese, and 43.8% were students in clinical medicine. While 76.5% had heard of HPV only 48.8% knew that the prevention of cervical cancer was possible through HPV vaccination. Only 42.9% of the male and 49.2% of the female students correctly answered over 10 out of 22 questions on HPV related knowledge. Female students appeared to know more about HPV and HPV vaccination (OR: 1.39; 95% CI: 1.11-1.75). In addition, the student knowledge improved with the grade (p<0.001). University courses were the most selected source of knowledge about HPV vaccination (66.4%). 83.6% of males and 91.4% of females were willing to have more HPV related education by experts (p<0.001). Only 10.1% of the students acknowledged that people had asked for their advice regarding HPV vaccination. Conclusions: Our survey indicates that medical students from Southwest China have poor knowledge of HPV and HPV vaccination, but are willing to receive more relevant information. Targeted education should be incorporated into school courses to inform these future health care providers and ensure success of programs for cervical cancer control and prevention.

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