The inactivation of E. coli asparaginase by 2,3-butanedione studied with L-asparagine and diazooxonorvaline as substrates obeys pseudo first order kinetics. Activity losses are linear with respect to arginine and histidine modification, with complete inactivation being correlated with alteration of one arginine and one histidine per subunit. The rate of inactivation of the enzyme was reduced in...

Our previous work established that DNA is naturally transferable on agar plates through a new transformation system which is regulated by the stationary phase master regulator RpoS in Escherichia coli. In this transformation system, neither additional Ca(2+) nor heat shock is required. Instead, transformation is stimulated by agar. The membrane protein OmpA, a gated pore permeable to ions and l...

Fumarate reductase from Escherichia coli functions both as an anaerobic fumarate reductase and as an aerobic succinate dehydrogenase. A site-directed mutation of E. coli fumarate reductase in which FrdB Pro-159 was replaced with a glutamine or histidine residue was constructed and overexpressed in a strain of E. coli lacking a functional copy of the fumarate reductase or succinate dehydrogenase...

In order to find a more satisfactory interpretation of the phenomenon of photosensitized inactivation of bacteria, studies were performed under various experimental conditions on methylene blue and E. coli. In summary the findings are as follow:- 1. The dye is absorbed by the bacteria according to the Langmuir isotherm and can be removed by ionic substitutions; the dye binding to the bacteria i...

We recently reported that phosphate-buffered saline (PBS) treated with nonthermal dielectric-barrier discharge plasma (plasma) acquires strong antimicrobial properties, but the mechanisms underlying bacterial inactivation were not known. The goal of this study is to understand the cellular responses of Escherichia coli and to investigate the properties of plasma-activated PBS. The plasma-activa...

This study evaluated the dynamic effects of free-chlorine (FC) concentration, contact time, and organic load on the inactivation of Salmonella, Escherichia coli O157:H7, and non-O157 Shiga toxin-producing E. coli (STEC) in suspension. Bacterial cells from four strains each of Salmonella, E. coli O157:H7, and non-O157 STEC were inoculated separately or as a multistrain cocktail into solutions wi...

The gene encoding the Lon protease of Erwinia amylovora has been cloned by complementation of an Escherichia coli lon mutant. Analysis of the determined nucleotide sequence of the lon gene revealed extensive homology to the nucleotide sequences of cloned lon genes from E. coli, Myxococcus xanthus, and Bacillus brevis. The predicted amino acid sequence of the E. amylovora Lon protease was 94, 59...

Hospital surfaces are a source of potential infection due to contamination by microorganisms such as bacteria and viruses. Bacterial biofilms particular importance, their persistence in the hospital environment. Cold atmospheric pressure plasma (CAPP) is novel method surface decontamination. In this study, we aimed show use CAPP jet for were grown on common materials treated with an air-driven ...

Inactivation mechanism of supercritical carbon dioxide (SC-CD) combination with Thymbra spicata essential oil (TEO) treatments on bacteria in tryptone soy broth (TSB) and juices was investigated. Salmonella Typhimurium significantly inactivated by 3.45 5.55 logs after SC-CD+TEO treatment TBS for 35 min at 7.6 10.13 MPa respectively. Klebsiella pneumoniae showed higher resistance to than other t...

Polynucleotide phosphorylase (PNPase) is reported to regulate virulence in Salmonella, Yersinia sp. and Campylobacter jejuni, yet its role in Escherichia coli O157:H7 has not been investigated. To gain insights into its roles in E. coli O157:H7 virulence, pnp deletion mutants were generated and the major virulence factors were compared to their parental wild type strains. Deletion of pnp in E. ...