Cytoplasmic expression of recombinant interleukin-2 and interleukin-4 proteins results in hydrogen peroxide accumulation and reduction in catalase activity in escherichia coil

The Reactive oxygen species [ROS] is induced in the cells following various stresses but the effect of recombinant protein expression on ROS generation has not been studied yet. In this study, H2O2 concentration and catalase activity variations and their correlation with cell growth following cytoplasmic expression of human interleukin-2 [hIL-2] and mouse interleukin-4 [mIL-4] in Escherichia coli were investigated. Additionally, the effect of recombinant protein expression under different conditions was compared to the effect of foreign DNA introduction on these factors. Plasmids pEThIL-2 and pETmIL-4 were used for expression of human interleukin-2 [hIL-2] and mouse interleukin-4 [mIL-4] inside the cytoplasm of the cells. Having confirmed protein expression using SDS-PAGE analysis and ELISA assay, H2O2 concentration and catalase activity were measured at various ODs. Empty vector introduction increased significantly H2O2 concentration of the cells. However, H2O2 concentration in hIL-2 and mIL-4 expressing cells was significantly higher than its concentration in empty vector transformed cells. Catalase activity was reduced in foreign DNA introduced cells. It was more lowered following expression of recombinant proteins. Results of this study revealed the relationship between foreign DNA introduction and protein expression with H2O2 elevation and catalase activity reduction. There was also correlation between H2O2 elevation and reduction in catalase activity with the cell growth depression

[Antagonistic ability of acid and bile tolerance Lactobacillus were isolated from dairy products]

In order to selected indigenous potential probiotic bacteria, we surveyed antagonistic activities of 22 strains of acid and bile toleran Lactobacillus, isolated from traditional dairy products by biochemical and molecular methods. In a fundamental practical study assessment of antimicrobial activity of this strain with neutralized and Dual layer two methods against bacterial pathogene such as E-coli, L. monocytogenes, S.auteus and Y.entercolitica was done. These strain were identified with two methods for determining of biochemical and sequence of 16 SrDNA. Dual layer method based on the growth of zone diameter were established in three groups of strains; inhibitors, semi inhibitors and non inhibitors. Neutralize method around well acidic extract containing strains C5i4, Y144, K213, C4ie, C612 and neutral extract C5i4 zone blight strains was observed. Based on the results, sequence area 16Sr DNA of four strains include C4i2, D1d2, Y2c4, D3b1 indicator bacteria that revealed the highest percentage of inhibitor effect of bacterial indicators, were duplicate and sequency. So four strains L.Bacilus Pentosus, L.Bacillus Bervis and L. Bacillus Paraplantarum, were identified respectively. It seems that indigenous lactobacillus from Iranian dairy products have potential as probiotics. So use of them as bio preservative prevent food bacterial contamination