Recent advance in the mechanism study of polymeric inhibitors of P-glycoprotein / 药学学报

P-glycoprotein (P-gp) is an ATP-dependent multidrug efflux pump that acts as a major obstacle for oral drug delivery and cancer therapy. Recent reports have provided evidence that excipients often used in pharmaceutical formulations, such as Pluronic and TPGS, also have inhibitory effects on P-glycoprotein. Because inhibition of efflux transporters by polymeric inhibitors may dramatically increase the bioavailability of P-gp substrates with negligible side effects, identification of the mechanism and their structure activity relationship is therefore of significant importance for pharmaceutical development. Other than competitive inhibition for traditional inhibitors, polymeric inhibitors may modify P-gp function through alterations on membrane fluidity, inhibition of P-gp ATPase, depletion of intracellular ATP and down-regulating of P-gp expression. In the present review, the inhibition mechanism of potential polymeric inhibitors and their structure activity relationship will be discussed along with a brief introduction to the established methodologies.

Study on the Nitrite-reducing Activity of Aerobic Denitrifying Bacterial Strain N6-1 / 微生物学通报

The nitrite-reducing activity of aerobic denitrifying bacterial strain N6-1 was studied. It showed that the nitrite-reducing activity reached the highest at 30℃, 120 r/min, pH 8.5 and C/N ratio 12, using CH3COONa and NaNO2 as the sole carbon source and nitrogen source, respectively. When the initial NaNO2 concentration was 2 g/L, NO2--N was reduced completely after 20 hours cultivation with the reducing rate of 20.3 mg/L?h. There would be no effect on its nitrite-reducing activity in the present of 1.5% NaCl or 1% peptone. The cell concentration could reach 1.2?1011 CFU/mL after 24 hours cultivation in 10 L fermentor.