The ppk gene of Streptomyces lividans encodes an enzyme catalyzing, in vitro, the reversible polymerization of the gamma phosphate of ATP into polyphosphate and was previously shown to play a negative role in the control of antibiotic biosynthesis (H. Chouayekh and M. J. Virolle, Mol. Microbiol. 43:919-930, 2002). In the present work, some regulatory features of the expression of ppk were estab...

OBJECTIVES To evaluate the effectiveness of hydrogen peroxide (HP) use as a disinfectant in the hospital water network for the control of Legionella spp. colonization. METHODS Following the detection of high levels of Legionella contamination in a 136-bed general hospital water network, an HP treatment of the hot water supply (25 mg/L) was adopted. During a period of 34 months, the effectiven...

In the present work using the IR spectroscopy method the effect of ethanol on structural transitions of DNA and polyphosphates under the action of Ca2+ ions in mixed solutions containing ethanol (0-25 vol.%) was studied. It was shown that, on its interaction with Ca2+ ions, in aqueous and mixed solutions DNA becomes transformed into compact form. With the increase of concentration of ethanol th...

The effect of polyphosphates (eight compounds) on growth of Staphylococcus aureus 196E in brain heart infusion broth was studied. The organism was sensitive (in decreasing order) to chain polyphosphates with 21, 3, 13, and 15 PO4 groups, and bactericidal effects were observed with 0.5% of these compounds. No inhibition was effected by PPi or a metaphosphate. The inhibitory effects were pH depen...

Measurement of polymerization degree of condensed phosphates was examined by solid-state NMR. Broad peaks of the NMR of endand middle-PO4 groups of condensed phosphates were observed at about 1 and -20 ppm, respectively. The NMR. peak area ratio (Ro) of middle-PO4 group to end-PO4 group has the following relation with the polymerization degree (n) of polyphosphate: Ro (middle-PO4/end-PO4) = (n-...

The effects of osmotic shocks on polyphosphates and on the vacuolar fluorescent indicator atebrin have been investigated to test whether acidic vacuoles in the halotolerant alga Dunaliella salina have a role in osmoregulation. Upshocks and downshocks induce different patterns of polyphosphate hydrolysis. Upshocks induce rapid formation of new components, tentatively identified as 5 or 6 linear ...

An overview of methods aiming at the determination of selected parameters of activated sludge models has been presented. The attention was paid to the model parameters being the most sensitive and dependent on the composition of biomass and/or substrate. These parameters should be determined experimentally. Methods based on the measurements of oxygen uptake rate are widespread use in this area....