Rhamnolipid biosurfactant is mainly produced by Pseudomonas aeruginosa that is the opportunistic pathogenic strain and not suitable for future industrial development. In order to develop a relatively safe microbial strain for the production of rhamnolipid biosurfactant, we constructed engineered Escherichia coli strains for rhamnolipid production by expressing different copy numbers of rhamnosyltransferase (rhlAB) gene with the constitutive synthetic promoters of different strengths in E. coli ATCC 8739. We further studied the combinatorial regulation of rhlAB gene and rhaBDAC gene cluster for dTDP-1-rhamnose biosynthesis with different synthetic promoters, and obtained the best engineered strain-E. coli TIB-RAB226. Through the optimization of culture temperature, the titer of rhamnolipd reached 124.3 mg/L, 1.17 fold higher than that under the original condition. Fed-batch fermentation further improved the production of rhamnolipid and the titer reached the highest 209.2 mg/L within 12 h. High performance liquid chromatography-mass spectrometry (LC-MS) analysis showed that there are total 5 mono-rhamnolipid congeners with different nuclear mass ratio and relative abundance. This study laid foundation for heterologous biosynthesis of rhanomilipd.
Bacterial Proteins ; genetics ; Batch Cell Culture Techniques ; Decanoates ; Escherichia coli ; metabolism ; Fermentation ; Glycolipids ; biosynthesis ; Hexosyltransferases ; genetics ; Industrial Microbiology ; methods ; Multigene Family ; Promoter Regions, Genetic ; Pseudomonas aeruginosa ; Rhamnose ; analogs & derivatives ; biosynthesis ; Surface-Active Agents ; metabolism

OBJECTIVETo establish an HPLC method for determination of chlorogenic acid and hydrochlorothiazide in Zhenjujiangyapian.

METHODThe HPLC method was carried on C18 column using methanol-0.1% phosphoric acid(20: 80) as mobile phase, and the detection wavelength was 327 nm, the flow rate was 1.0 mL x min(-1) and the temperature of column was 40 degrees C.

RESULTIn the HPLC method, the calibration curve for chlorogenic acid, hydrochlorothiazide were linear in the range of 0.049 6-0.496 (r = 0.999 5) and 1.002-10.02 microg (r = 0.999 8). The average recovery for chlorogenic acid, hydrochlorothiazide were 101.0% and 100. 1%. RSD were 2.0% and 1.4% (n = 9), respectively.

CONCLUSIONThe method is convenient, precise and reliable for determining the content of chlorogenic acid and hydrochlorothiazide in Zhenjujiangyapian.

Antihypertensive Agents ; analysis ; Chlorogenic Acid ; analysis ; Chromatography, High Pressure Liquid ; methods ; Drugs, Chinese Herbal ; analysis ; Hydrochlorothiazide ; analysis

Objective To evaluate the effectiveness of multi-disciplinary team (MDT) mode in the prevention and control of multidrug resistant organism (MDRO) infection in lung transplant recipients. Methods Lung transplant recipients admitted to the hospital from 2019 to 2022 were enrolled. MDT expert group was established in January, 2020. A series of prevention and control measures were conducted. The implementation rate of MDRO prevention and control measures and the detection rate of MDRO on the environmental surface from 2020 to 2022, and the detection rate of MDRO in lung transplant recipients from 2019 to 2022 were analyzed. Results The overall implementation rate of MDRO prevention and control measures for medical staff was increased from 64.9% in 2020 to 91.6% in 2022, showing an increasing trend year by year (P<0.05). The detection rate of MDRO on the environmental surface was decreased from 28% in 2020 to 9% in 2022, showing a downward trend year by year (P<0.05). The detection rate of MDRO in lung transplant recipients was decreased from 66.7% in 2019 to 44.3% in 2022, showing a decreasing trend year by year (P<0.001). Conclusions MDT mode management may enhance the implementation of MDRO prevention and control measures for medical staff, effectively reduce the infection rate of MDRO in lung transplant recipients and the detection rate of MDRO on the environmental surface, which is worthy of widespread application.