1.Expression,purification and renaturation of recombinant human collagen-binding bone morphogenetic protein-2 from Escherichia coli
Naipeng WU ; Yu WANG ; Jia SONG ; Zhenxu WU ; Tianlin GAO ; Xiangru FENG ; Chuan FU ; Zongliang WANG ; Chunyan WANG
Journal of Jilin University(Medicine Edition) 2016;42(2):226-230
Objective:To construct the Escherichia coli (E. coli)expression system for preparation of the bone morphogenetic protein-2 (BMP2)with collagen-binding domain (CBD),and to study the methods and conditions for expression, purification and renaturation of CBD-BMP2.Methods:CBD sequence was cloned into the N-terminal of BMP2 sequence, the recombinant vector pet21b/CBD-BMP2 was constructed and transformed into E.coli BL21.The expression of recombinant protein was induced using isopropylβ-D-thiogalactopyranoside (IPTG) at 37 ℃.Ni-NTA chelate chromatography was used to purify CBD-BMP-2.Denaturing CBD-BMP2 was refolded by dilution method using ultrapure water.The refolding CBD-BMP2 was filtered through a 0.22μm microfiltration membrane for degermation.The recovery rate was calculated by the ratio of the protein concentration before and after degermation. The expression, purification, and renaturation of recombinant protein were detected by SDS-PAGE method.The concentration of CBD-BMP2 was detected by BCA assay.Results:The recombinant vector pet21b/CBD-BMP2 was successfully transformed into E.coli BL21,and the recombinant protein was expressed as inclusion bodies in E.coli.The SDS-PAGE results showed denaturing protein was dissolved in supernatant of lysis buffer with 8 mol·L-1 urea and the purified recombinant protein existed in elution buffer B with relative molecular mass about 14 000.Two bands (14 000 and 28 000)were seen in the SDS-PAGE picture,which indicated that the monomer was successfully refolded into dimer by dilution method.The concentrations of recombinant protein before and after degermation were 110 and 80 mg · L-1 , respectively, and the recovery rate was about 73%. Conclusion:The recombinant vector pet21b/CBD-BMP2 is transformed into E.coli BL21 successfully,and the recombinant CBD-BMP2 is expressed and refolded efficiently. The methods of prokaryotic expression system for preparing recombinant CBD-BMP2 protein are established.
2. Investigation of a local dengue fever outbreak associated with serotype 1 virus in Fuzhou, 2017
Naipeng KAN ; Jinzhang WANG ; Shenggen WU ; Libin YOU ; Yongjun ZHANG ; Yuwei WENG
Chinese Journal of Experimental and Clinical Virology 2019;33(6):598-602
Objective:
To elucidate the epidemiological and etiological features of a local outbreak of dengue fever (DF) in Taijiang district in Fuzhou, Fujian province in 2017, and speculate possible viral source based on phylogenetic analysis.
Methods:
The clinical and demographic data of cases were collected through field investigation and the outbreak was characterized epidemiologically by descriptive method. The patient′s serum were collected and the adult mosquitoes were captured by anti-mosquito double-net method for the laboratorial test and viral isolation. The viral isolates were typed by real-time fluorescent RT-PCR and their full length of viral envelope (E) genes were amplified by RT-PCR and sequenced. The E gene sequences obtained in this study, together with the reference sequences, were used for the phylogenetic analysis.
Results:
A total of 13 cases of autochthonous DF were confirmed in the outbreak. All cases presented obvious clinical manifestations and clustered spatially and temporally. The Breteau Index (BI) of mosquito larva density was the highest in epidemic foci of Xingang street and was relatively low in surrounding areas. Four DENV-1 strains, three from patients and one from the captured adult
3.Exposure-response relationship between air pollutants, temperature, and risk of hospital admission for type 2 diabetes mellitus
Fei ZHAI ; Naipeng LIU ; Shenshen WU ; Jiajia WANG
Journal of Environmental and Occupational Medicine 2024;41(10):1109-1114
Background The population with diabetes in China is increasing year by year. Current research has found that either air pollution or temperature has an impact on the occurrence and development of diabetes, but the interaction between the two is unclear yet. Objective To investigate the effects and the lag effects of air pollutants and temperature on the risk of hospital admission for type 2 diabetes in Hefei, Anhui Province from 2016 to 2019, as well as to verify potential interaction between air pollutants and temperature. Methods This study collected hospital admission data for patients with type 2 diabetes from a tertiary hospital in Hefei, Anhui Province, and the corresponding monitoring data on air pollutants and meteorological factors from 2016 to 2019. Firstly, a distributed lag non-linear model (DLNM) was used to explore the effects of air pollutants and temperature on the risk of hospital admission for type 2 diabetes. Subsequently, a bivariate response surface model was used to explore potential interaction between temperature and various pollutants on frequency of hospital admission due to diabetes. Temperature was further divided into lower, medium, and higher levels by percentiles during the study period, and the potential interaction between air pollutants and temperature strata were verified . Results After controlling long-term trend, seasonal trend, holiday effect, and day of the week effect, the results of single pollutant models showed that for every 10 μg·m−3 increase in fine particulate matter (PM2.5), inhalable particulate matter (PM10), and nitrogen dioxide (NO2), the relative risk (RR) values for hospital admission due to type 2 diabetes were 1.032 (95%CI: 1.021, 1.043), 1.018 (95%CI: 1.008, 1.026), and 1.037 (95%CI: 1.016, 1.058), respectively; for every 1 mg·m−3 increase in carbon monoxide (CO), the RR value for hospital admission due to type 2 diabetes was 1.319 (95%CI: 1.163, 1.495); the increases in sulfur dioxide (SO2), ozone (O3), and daily average temperature showed no statistically significant impact on hospital admission due to type 2 diabetes. The results of bivariate response surface models suggested that daily average temperature and various pollutant levels spontaneously affected the risk of hospital admission for type 2 diabetes, but the stratified analysis did not find significant differences in the effect of PM2.5 on the risk of hospital admission due to type 2 diabetes across different temperature strata. Conclusion Increases in the concentrations of PM2.5, PM10, NO2, and CO elevate the risk of hospital admission for type 2 diabetes. This study could not confirm the interactions between daily average temperature and various pollutants.