Reduced redox potential during growth of some gram-negative bacteria. Effect on the biochemical and physicochemical surface properties and phagocytosis by polymorphonuclear leukocytes

Abstract

When cultivated at reduced redox potential the physico-chemical surface properties were altered in strains of E. coli, Salmonella and Yersinia bacteria. In particular, strains which showed hydrophilic surface properties under normal aerobic cultivation became more hydrophobic when exposed to anaerobic conditions (e.g. E. coli K12, E. coli K12D21, E. coli K12D22, S. minnesota S99, S. typhimurium 395MS, S. braenderup 2828 and Yersinia enterocolitica). Moreover, there were qualitative as well as quantitative differences in the protein profiles of whole bacterial lysates and membrane preparations analysed in SDS-PAGE. There were no qualitative differences in the lipopolysaccharide (LPS) bands. However, when E. coli K12D22 were cultivated aerobically, remarkably more high molecular temperature-sensitive (70 degrees C for 45 min) carbohydrate material was produced (weight about 360 KD and 660 KD). Interaction between polymorphonuclear leukocytes (PMNL) and the E. coli K12D22 strain, measured as chemiluminescence, showed that the anaerobically cultivated bacteria induced a chemiluminescence that was mainly of intracellular origin, while the aerobically cultivated induced an extracellular response. Phagocytosis and killing-studies showed that only anaerobically-grown E. coli were effectively inactivated by the PMNL.