The study of the effect of photooxidative stress on porin protein synthesis in E. coli

OmpF and OmpC are the porin proteins located in outer membrane of E. coli and their synthesis proportions change depending on the environmental factors. In this study, the effect of the envZ, ompR and pta mutations on this change, the change of the porin protein synthesis, the role of OmpF and OmpC porin proteins of E. coli for survival under photooxidative stress in lake water were investigated. According to the data we acquired from different temperatures in lake water, it was determined that the mutations of ompF and ompC gene under photo-oxidative stress increases the survival time of E. coli. While the t90 value of wild type E. coli at 37°C was in 19.4 hours, ompR mutant (MH1160) E. coli was observed in 8 minutes. But t90 value of MSR31 (ompR-) was observed in more than 48 hours. Thus it is thought that OmpR is related with oxidative stress. While the synthesis of OmpF porin proteins decreased independently of the photooxidative stress because of the circumstances of the lake, the synthesis of OmpC porin proteins decreased depended on the photooxidative stress in lake water. It was determined that the mutations of envZ and pta gene did not have any effect for synthesis of OmpC and OmpF of E. coli under the photooxidative stress. It was observed that mannitol which is an antioxidant substance had protective effect under photooxidative stress and moreover, a relationship between porin protein synthesis and mannitol was observed.Key words: Photooxidative stress, Lake Water, Mannitol, Porin proteins.