In several Escherichia coli K-12 strains grown on a limiting concentration of glucose, isocitrate dehydrogenase (IDH) was inactivated about 90% after cessation of growth upon exhaustion of the glucose. Such inactivation has been previously observed in several E. coli strains but not in E. coli K-12 (unless acetate was added to the bacterial culture when growth ceased). IDH was inactivated 75 to...

The response of a representative virus and indicator bacteria to heating, solar irradiation, or their combination, was investigated in a controlled solar simulator and under real sun conditions. Heating showed higher inactivation of Escherichia coli compared to the bacteriophage MS2. Heating combined with natural or simulated solar irradiation demonstrated a synergistic effect on the inactivati...

This work explores the bactericidal effect of (+)-limonene, the major constituent of citrus fruits' essential oils, against E. coli. The degree of E. coli BJ4 inactivation achieved by (+)-limonene was influenced by the pH of the treatment medium, being more bactericidal at pH 4.0 than at pH 7.0. Deletion of rpoS and exposure to a sub-lethal heat or an acid shock did not modify E. coli BJ4 resis...

Background: Ciprofloxacin induces SOS response and mutagenesis by activation of UmuD’2C (DNA polymerase V) DinB IV) in Escherichia coli, leading to antibiotic resistance during therapy. Inactivation DNA V can result the inhibition E. coli. Objectives: The aim this research was investigate effect UmuC inactivation on ciprofloxacin coli mutants. Methods: Ciprofloxacin-resistant mutants were produ...

Suspensions of Escherichia coli and Bacillus subtilis spores were exposed to conventional thermal and microwave energy at 2,450 MHz. The degrees of inactivation by the different energy sources were compared quantitatively. During the transient heating period by microwave energy, approximately a 6 log cycle reduction in viability was encountered for E. coli. This reduction was nearly identical t...

The inactivation of Escherichia coli by microalloyed aluminium based composite was studied. The composite is material in form of steel wire, plated by microalloyed aluminium. Its effects are based on spontaneous dissolution in contact with water, with generation of Al(III) and OH ̄ ions, and finally voluminous insoluble Al(OH)3. Bearing in mind its great efficacy in purification of water from ma...

In steadily flowing water at 20 degrees C and pH 7, five organisms had the following order of resistance to ozone (at constant levels of ozone): poliovirus 1 (PV1) less than Escherichia coli less than hepatitis A virus (HAV) less than Legionella pneumophila serogroup 6 less than Bacillus subtilis spores. The tests were repeated at 10 degrees C with HAV, PV1, and E. coli. Ozone inactivation of H...

AIMS To investigate the effect of extrinsic control parameters for ozone inactivation of E. coli in a bubble column. METHODS AND RESULTS Ozone inactivation of Escherichia coli ATCC 25922 in Tryptic Soya Broth was examined. The parameters studied included temperature (ambient, 20, 25 and 30 degrees C), exposure time (up to 30 min), gas flow rate (0.03, 0.06, 0.12, 0.25, 0.5 and 0.75 l min(-1))...

Bacterial inactivation by 405 nm light is accredited to the photoexcitation of intracellular porphyrin molecules resulting in energy transfer and the generation of reactive oxygen species that impart cellular oxidative damage. The specific mechanism of cellular damage, however, is not fully understood. Previous work has suggested that destruction of nucleic acids may be responsible for inactiva...

Quantifying the effect that nanofiber mat chemistry and hydrophilicity have on microorganism collection and inactivation is critical in biomedical applications. In this study, the collection and inactivation of Escherichia coli K12 was examined using cellulose nanofiber mats that were surface-functionalized using three polyelectrolytes: poly (acrylic acid) (PAA), chitosan (CS), and polydiallyld...