High cell-density fermentation of shark hepatical stimulator analogue in Escherichia coli / 生物工程学报

The potential effects of recombinant shark hepatical stimulator analogue (r-sHSA) in liver disease have been revealed in our previous studies. In order to further evaluate its clinic application, we carried out high cell-density fermentation in 5 L fermentor to get enough products. Based on the trials in shaking flask, we optimized the parameters for 5 L fermentor, including medium composition, medium supplement, inducer concentration and induction time, etc. In detail, the improved LB medium (0.97% glycerol, 0.91% yeast extract, 0.72% tryptone, 0.782% KH2PO4, 0.267% K2HPO4.3H2O, 0.062% MgSO4.7H2O, 0.5% NaCl, pH 7.0) is chosen to cultivate the engineering bacteria with the constant fermentation condition (pH 7.0, and the dissolved oxygen concentration is about 25%-30%). When bacterial culture reaches exponential phase, the modified feeding medium (620 g/L glycerol, 94.8 g/L tryptone, 3.3 mL/L trace elements, and 7.5 g/L MgSO4.7H2O) is then supplied through the method of exponential fed-batch mode. After the optical density (OD600) of engineering bacterial culture reaches to 23, the ultimately concentration of 0.5 mmol/L IPTG is added to induce the expression of r-sHSA for 6 h. Results show that the amount of r-sHSA production is (2.662 +/- 0.041) g/L, which is about 13.7 folds of the one optimized before.

Antimicrobial and antitumor activities of extracts from the roots of Kandelia candel / 中国海洋药物

Objective To investigate the antimicrobial and antitumor activities of extracts from the root of mangrove plant,Kandelia candel.Methods Micro-dilution and MTT method were used to test the antimicrobial and antitumor activities of extracts from the root of K.candel.Results The petroleum ether extracts of root could inhibit the growth of Staphylococcus aureus,S.epidermidis,Bacillus subtilis and Sarcina lutea with the minimal inhibitory concentration(MIC) of 3.125 mg?mL-1,1.5625 mg?mL-1,0.78125 mg?mL-1 and 3.125 mg?mL-1 respectively.The ethyl acetate extracts and ethyl alcohol extracts could inhibit the growth of S.epidermidis with MIC of 3.13 mg?mL-1 and 6.25 mg?mL-1 respectively.At the same time,the petroleum ether extracts could inhibit the proliferation of tumor cells,such as SMMC-7721,B16,BGC803 and HepG2 with IC50 of 355.2?g?mL-1,378.6?g?mL-1,275.6?g?mL-1 and 411.6?g?mL-1 respectively,while the other extracts could stimulate the proliferation of tumor cells apparently.Conclusion The antimicrobial and antitumor activities of extracts from the root of K.candel indicate the potential pharmaceutical usage of this plant.