ABSTRACT
The effect of methanol addition on the heterologous expression of isoprenyl transferase NovQ was studied in Pichia pastoris Gpn12, with menadione and isopentenol as precursors to catalyze vitamin K2 (MK-3) synthesis. The expression of NovQ increased by 36% when 2% methanol was added every 24 h. The influence of initial pH, temperature, methanol addition, precursors (menadione, isopentenol) addition, catalytic time and cetyltrimethyl-ammonium bromide (CTAB) addition were explored in the P. pastoris whole-cell catalytic synthesis process of MK-3 in shaking flask. Three significant factors were then studied by response surface method. The optimal catalytic conditions obtained were as follows: catalytic temperature 31.56 ℃, menadione 295.54 mg/L, catalytic time 15.87 h. Consistent with the response surface prediction results, the optimized yield of MK-3 reached 98.47 mg/L in shaking flask, 35% higher than that of the control group. On this basis, the production in a 30-L fermenter reached 189.67 mg/L when the cell catalyst of 220 g/L (dry weight) was used to catalyze the synthesis for 24 h. This method laid the foundation for the large-scale production of MK-3 by P. pastoris Gpn12.
ABSTRACT
OBJECTIVE:To provide reference for further promoting the rational use of antimicrobial drugs in the rural commu-nity health service stations. METHODS:4 800 prescriptions were collected from 8 community health service stations affiliated to our hospital from Jan. 1,2012 to Dec. 31,2014,the use of antimicrobial drugs in the prescriptions was statistically analyzed and the indicators were compared before and after intervention. RESULTS:The proportion of use of antimicrobial drugs in these com-munity health service stations was decreased from 52.88%in 2012 to 30.38%in 2014;the clinical diagnosis of prescription of anti-microbial drug was mainly respiratory infections;what the most used types of antibacterial drugs was cephalosporins;and the pro-portion of antimicrobial drug of irrational use was decreased from 43.50%(368/846)in 2012 to 22.84%(111/486)in 2014. CON-CLUSIONS:The combination of technique and administrative intervention is remarkable. However,the unreasonable use of antibac-terial drugs still exists. Therefore,related training should be organized,and the proportion of use of antimicrobial drugs should in-cluded in the performance appraisal to further improve the use level of antimicrobial drugs in the rural community health service sta-tions.