ABSTRACT
Background and Objectives: The purpose of the present study was to investigate effects of various heat shock conditions and fast freezing and subsequent thawing on the viability and recovery of Bacillus coagulans and Bacillus subtilis as probiotic Sporeformers, and also to compare spore plate and microscopic counts
Materials and Methods: After preparing the final suspensions of B. coagulans and Bacillus suhtilis subsp. Natto spores, they were spread-plated before and after fast freezing treatment [-70°C for about 1 min]. Heat shock treatments of the spores were carried out at 68°C for 15, 20, and 30 min as well as at 80°C for 10 and 15 min. Concentrations of the examined probiotic Sporeformers were determined simultaneously by plate enumerations and microscopically determined counts. Student's t-test and one-way analysis of variance [ANOVA] of SPSS were used for statistical analysis of the data. Analysis of DoE results was carried out using Minitab
Results: The results presented here show that the highest recovery rates for B. coagulans [14.75 log CFU/mL] and B. subtilis spores [14.80 log CFU/mL] were under a heat shock condition of 68°C for 20 min in nutrient agar [p<0.05]
In addition, the survival rates of B. coagulans and B. subtilis spores under the fast freezing and subsequent thawing condition were about 90% and 88%, respectively. Plate counts differed significantly from counts determined microscopically, with differences of almost 0.5 and 0.8 log for B. coagulans and B. subtilis spores, respectively [p<0.05]
In addition, DoE results of the study revealed that both factors of spore count method and only freezing factor in fast freezing treatment have a significant effect on concentrations of the spores examined [p<0.05]
Conclusions: Heat shock conditions, freezing and subsequent thawing circumstances, and plate counts or enumerations determined microscopically have significant influences on the viability of probiotic Sporeformers and should be considered in determining of their accurate concentrations
ABSTRACT
Emergence of drug resistance has brought major problems in chemotherapy. Using nutrients in combination with chemotherapy could be beneficial for improvement of sensitivity of tumors to drug resistance. Soybean-derived isoflavones have been suggested as chemopreventive agents for certain types of cancer, particularly breast cancer. In this study, the synergistic effects of soy isoflavone extract in combination with docetaxel in murine 4T1 breast tumor model were investigated. In this study, mice were divided into 4 groups [15 mice per group] of control, the dietary Soy Isoflavone Extract [SIE, 100 mg/kg diet], the Docetaxel [DOCE, 10 mg/kg] injection and the combination of dietary soy isoflavone extract and intravenous docetaxel injection [DOCE+SIE]. After 3 injections of docetaxel [once a week], 7 mice were sacrificed to analyze MKI67 gene and protein expressions and the rest were monitored for diet consumption, tumor growth and survival rates. In DOCE+SIE group, diet consumption was significantly higher than DOCE group. While lifespan showed a trend towards improvement in DOCE+SIE group, no significant difference was observed among the 4 studied groups. Tumor volume was not significantly affected in treated groups. A lower but not significant MKI67 protein expression was detected in western blot in DOCE+SIE group. The mRNA expression was not significantly different among groups. The results suggest that the combination of soy isoflavone as an adjunct to docetaxel chemotherapy can be effective in improving diet consumption in breast cancer