Abstract Background Salmonella belongs to the Enterobacteriaceae family, a gram-negative, non-spore-forming, rod-shaped, motile, and pathogenic bacteria that transmit through unhygienic conditions. It is estimated 21 million new infections arise every year, resulting in approximately 200,000 deaths. more prevalent among children, old aged, immunocompromised individuals. The frequent usage of cl...

Within minutes of Bdellovibrio bacteriovorus attack on prey cells, such as Escherichia coli, the cytoplasmic membrane of the prey is altered. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of purified invaded prey cell (bdelloplast) membranes revealed the appearance of a noncytoplasmic membrane protein. This protein is not observed in preparations of noninvaded E. coli membranes and ...

The in-vitro activity of five new fluoroquinolones, WIN 57273, sparfloxacin, fleroxacin, temafloxacin and ciprofloxacin was determined against 543 recent clinical isolates and eight quinolone resistant strains derived by mutation and their five parent strains. WIN 57273 was the most active compound against Gram-positive bacteria, sparfloxacin had a broad spectrum which was similar to that of ci...

Using clinical strains of Serratia marcescens with low and high resistance to extended-spectrum beta-lactam antibiotics, the relative contribution of chromosomal beta-lactamase and defective outer membrane porins to resistance was determined. Low-level resistance was caused by overproduced beta-lactamase alone. High-level resistance was due to beta-lactamase overproduction and defects of porin ...

The major outer membrane protein patterns of 45 Escherichia coli strains of human origin were compared with that of E. coli K12 by sodium dodecyl sulphate-polyacrylamide gel electrophoresis. Preparations of the former strains contained between two and five major bands in the molecular weight range between 30 000 and 42 000. The patterns were very heterogeneous with respect to the numbers and el...

The lipopolysaccharide and porin profile of Escherichia coli ATCC 25922, a smooth strain commonly used in antibiotic susceptibility testing, and five isogenic rough mutants was examined. The lipopolysaccharide of the parent strain had the characteristic ladder pattern on polyacrylamide gels, while that of the mutants appeared similar to chemotypes Ra and Rc of Salmonella typhimurium with some c...

Three membrane proteins, OmpF porin from Escherichia coli, bacteriorhodopsin from Halobacterium salinarium, and the hexagonally packed intermediate (HPI) layer from Deinoccocus radiodurans, were investigated with the atomic force microscope in buffer solution. A resolution of up to 0.8 nm allowed structural differences of individual proteins to be detected. OmpF porin exhibits different static ...