Distribution of the COVID-19 Epidemic and Correlation with Population Emigration from Wuhan, China / 中华医学杂志(英文版)

Background The ongoing new coronavirus pneumonia (Corona Virus Disease 2019,COVID-19) outbreak is spreading in China, but it has not yet reached its peak. Five million people emigrated from Wuhan before lockdown, potentially representing a source of virus infection. Determining case distribution and its correlation with population emigration from Wuhan in the early stage of the epidemic is of great importance for early warning and for the prevention of future outbreaks. Methods The official case report on the COVID-19 epidemic was collected as of January 30, 2020. Time and location information on COVID-19 cases was extracted and analyzed using ArcGIS and WinBUGS software. Data on population migration from Wuhan City and Hubei province were extracted from Baidu Qianxi, and their correlation with the number of cases was analyzed. Results The COVID-19 confirmed and death cases in Hubei province accounted for 59.91% (5806/9692) and 95.77% (204/213) of the total cases in China respectively. Hot spot provinces included Sichuan and Yunnan, which are adjacent to Hubei. The time risk of Hubei province on the following day was 1.960 times that on the previous day. The number of cases in some cities was relatively low, but the time risk appeared to be continuously rising. The correlation coefficient between the provincial number of cases and emigration from Wuhan was up to 0.943. The lockdown of 17 cities in Hubei province and the implementation of nationwide control measures efficiently prevented an exponential growth in the number of cases. Conclusion The population that emigrated from Wuhan was the main infection source in other cities and provinces. Some cities with a low number of cases showed a rapid increase in case load. Owing to the upcoming Spring Festival return wave, understanding the risk trends in different regions is crucial to ensure preparedness at both the individual and organization levels and to prevent new outbreaks.

Cloning, expression and purification of novel gene Rv2742 in Mycobacterium tuberculosis H37Rv / 生物工程学报

Rv2742 is a novel gene identified from Mycobacterium tuberculosis H37Rv by the proteogenomics strategy. The aim of this study was to establish a system of soluble expression and purification of the missing protein Rv2742 in M. tuberculosis H37Rv, to provide reference for further research on the biological function of Rv2742. The soluble protein was not successfully induced by prokaryotic expression vectors pGEX-4T-2-Rv2742, pET-32a-Rv2742, pET-28a-Rv2742 and pMAL-c2X-Rv2742. After the codon of novel gene Rv2742 was optimized according to E. coli codon usage frequency, only the recombinant strain containing plasmid pMAL-c2X-Rv2742 could produce soluble products of Rv2742 encoding gene. In addition, the expression effects of the desired fusion protein were also analyzed under different conditions including hosts, culture temperatures and IPTG concentrations. The optimum expression conditions were as follows: Rosetta (DE3) host, 16 °C culture temperature and 0.5 mmol/L IPTG. After being purified by affinity chromatography with amylose resin, the fusion protein sequence was confirmed by LC-MS/MS. These results indicated that the novel gene Rv2742 product could be successfully induced and expressed in a soluble form by the expression system pMAL-c2X with MBP tag. Our findings provide reference for studies on potential interaction and immunogenicity.

Effect of Different Processing Methods on the Content of Gallic Acid in Radix et Rhizoma Rhei / 中药新药与临床药理

Objective To establish a HPLC method for the determination of gallic acid in Radix et Rhizoma Rhei and to study the changes of gallic acid content in Radix et Rhizoma Rhei during processing. Methods HPLC method was used to detect gallic acid content. Diamonsil C18(250 mm?4.6 mm,5?m) column was used,and the mobile phase was a mixed liquid of MeOH -0.01 %H3PO4(10∶90). The column temperature was set up at 30℃,the flow rate was 1 mL?min-1,and the detecting wave-length was 273 nm. Results There were obvious differences of gallic acid content between the crude herbal material and different kinds of processed products of Radix et Rhizoma Rhei. The content of gallic acid was decreased in Radix et Rhizoma Rhei prepared by wine,but was increased in Radix et Rhizoma Rhei prepared by steaming with wine and by stewing with wine,and in charred Radix et Rhizoma Rhei. Conclusion The different processing methods have certain effect on the content of gallic acid in Radix et Rhizoma Rhei.