Improved protease activity of Pixian broad bean paste with cocultivation of Aspergillus oryzae QM-6 and Aspergillus niger QH-3

BACKGROUND: The preparation of broad bean koji is a key process in the production of Pixian broad bean paste (PBP). Protease is essential for the degradation of proteins during PBP fermentation. To obtain broad bean koji with high protease activity using the cocultivated strains of Aspergillus oryzae QM-6 (A. oryzae QM-6) and Aspergillus niger QH-3 (A. niger QH-3), the optimization of acid and neutral protease activities was carried out using Box­Behnken design with response surface methodology (RSM). RESULTS: The optimum conditions were found to be as follows: inoculation proportion (X1), 3:1 (A. oryzae QM-6: A. niger QH-3, w/w); culture temperature (X2), 33°C; inoculum size (X3), 0.5% (w/w); incubation time (X4), 5 d. The acid and neutral protease activities were 605.2 ± 12.4 U/g and 1582.9 ± 23.7 U/g, respectively, which were in good agreement with the predicted values. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis profiles revealed that the broad bean koji extracellular proteins in the case of cocultivation were richer compared to those in the case of A. oryzae QM-6 or A. niger QH-3 strain only. In addition, the free amino acids (FAAs) in the fermentation product were 55% higher in the cocultivation process than in that involving only A. oryzae QM-6, further confirming the diversity of proteases in the fermentation products. CONCLUSIONS: The optimal conditions of koji-making in PBP were obtained using RSM. The cocultivation of A. oryzae and A. niger increases the overall enzyme activities in the culture medium and the FAAs content, which would thus have potential application in the PBP industry.

Alcohol promotes the tumorigenesis of spontaneous breast cancer in TA2mice and the possible potential mechanism / 中国实验动物学报

Objective To explore whether alcohol promotes the development of breast cancer in TA2 mice and the possible potential mechanism. Methods Thirty-two 6-8-week old nulliparous female TA2 mice were randomly divided into control and ethanol-exposure groups, 16 mice in each group. The mice of the ethanol-exposure group were given 2%ethanol in drinking water, and the mice of control group received regular drinking water. Serum ethanol concentration in the TA2 mice was measured using an ANALOX AM1 alcohol analyzer. The incidence of breast cancer, tumor growth rate and tumor size of the ethanol-exposure and control groups were observed and compared. The estrogen levels of the two groups was detected by enzyme-linked immunosorbent assay ( ELASA) . Results Compared with the control group, the tumor for-mation rate of spontaneous breast cancer in the alcohol-exposure group was significantly increased (62. 5% vs. 43. 75%, P<0. 05), the average number of days of tumor formation was shortened (285 days vs. 335 days, P<0. 05), the tumor weight and volume were increased but not significant ( P>0. 05 ) , and the level of estrogen in the ethanol-exposure mice was significantly higher than that in the control group ( P>0. 05 ) . Conclusions Alcohol promotes the tumorigenesis of spontaneous breast cancer in TA2 mice, which may be associated to the increase of estrogen levels.

Alcohol promotes the tumorigenesis of spontaneous breast cancer in TA2mice and the possible potential mechanism / 中国实验动物学报

Objective To explore whether alcohol promotes the development of breast cancer in TA2 mice and the possible potential mechanism. Methods Thirty-two 6-8-week old nulliparous female TA2 mice were randomly divided into control and ethanol-exposure groups, 16 mice in each group. The mice of the ethanol-exposure group were given 2%ethanol in drinking water, and the mice of control group received regular drinking water. Serum ethanol concentration in the TA2 mice was measured using an ANALOX AM1 alcohol analyzer. The incidence of breast cancer, tumor growth rate and tumor size of the ethanol-exposure and control groups were observed and compared. The estrogen levels of the two groups was detected by enzyme-linked immunosorbent assay ( ELASA) . Results Compared with the control group, the tumor for-mation rate of spontaneous breast cancer in the alcohol-exposure group was significantly increased (62. 5% vs. 43. 75%, P<0. 05), the average number of days of tumor formation was shortened (285 days vs. 335 days, P<0. 05), the tumor weight and volume were increased but not significant ( P>0. 05 ) , and the level of estrogen in the ethanol-exposure mice was significantly higher than that in the control group ( P>0. 05 ) . Conclusions Alcohol promotes the tumorigenesis of spontaneous breast cancer in TA2 mice, which may be associated to the increase of estrogen levels.