PHAGE-BACTERIA INTERACTIONS UNDER METAL STRESS: A STUDY OF THE NOVEL STENOTROPHOMONAS MALTOPHILIA PHAGE VB_STM18.

Stenotrophomonas maltophilia is a highly adaptable gram-negative bacteria, demonstrating resilience in metal-contaminated environment, which makes it a key subject for understanding microbial survival under heavy metal stress. This study investigates the effects of cadmium ions (Cd²⁺) on the growth dynamics, cadmium uptake, and bacteriophage vB_Stm18-host interactions, with implications for environmental microbiology and applied biotechnology. Growth analysis revealed that S.

Effect of Zn(II) on the reduction and accumulation of Cr(VI) by Arthrobacter species.

Natural habitats are often characterized by the coexistence of Zn and Cr. This study assessed the potential of two Gram-positive, Cr(VI)-reducing, aerobic bacterial strains belonging to Arthrobacter genera, which were isolated from basalt samples taken from the most polluted region of the Republic of Georgia, to remediate Cr(VI) in environments in the presence of Zn(II). Our batch experiments revealed that the addition of Zn(II) to the tested bacterial cells significantly enhanced the accumulation of Cr.

Decomposition of Cr(V)-diols to Cr(III) complexes by Arthrobacter oxydans.

We demonstrated previously that Cr(VI) is readily reduced to oxoCr(V)-diols at the surface of Arthrobacter oxydans-a Gram-positive aerobic bacteria isolated from Columbia basalt rocks originated from a highly contaminated site in the USA. Here, we report an electron spin resonance (ESR) study of Cr(III) hydroxide formation from Cr(V)-diols by this bacterial strain as cells were exposed to 35, 200, and 400 mg/L of Cr(VI) under aerobic conditions as a batch culture and as lyophilized cells. The time-dependent ESR measurements show that the half-time of Cr(III) formation is almost equal to that of Cr(V) decomposition, which is in the range of 3-6 days for all cases.

[Interaction of Pb(II) ions with C-phycocyanin from Spirulina platensis: effect of ionic strength].

The effect of Pb(II) ions on C-phycocyanin from Spirulina platensis was studied by the method of fluorescence spectroscopy. The efficiency of quenching was analyzed using the Stern-Volmer relation. Isotherms of adsorption were constructed, and the constants of binding of Pb(II) ions to C-phycocyanin in solutions of varying ionic strength were determined by equilibrium dialysis and atomic absorption spectroscopy.

[Constants of binding of Pb(II) ions with DNA at various ionic strength].

The energetics of Pb(II) ion binding to DNA was determined from their binding isotherms by equilibrium dialysis and atomic absorption spectroscopy at different ionic strengths. Two types of binding of Pb(II) ions to DNA at different NaCl concentrations were observed.

[Binding of Cd(II) ions by C-phycocyanin during Spirulina platensis cell growth].

Modern effective methods of preparative biochemistry were used to obtain a highly purified preparation of the globular protein C-phycocyanin from Cyanophyceae strain IPPAS B-256. It was shown that C-phycocyanin accumulates endogeneous Cd(II) during the growth of Spirulina platensis cells.

[Ca2+, Mg2+, Zn2+ levels in histone fractions from normal and tumor cells].

Distribution of some bivalent cations (Ca2+, Mg2+, Zn2+) in histones isolated from healthy mice liver and ascitic hepatoma 22A cells has been investigated by atomic-absorption analysis. It has been shown that the content of these cations is higher in normal and diseased H3, H2B and H1 fractions and lower--in H2A; however, in the H4 fraction these metals are not detected. A significant increase of Ca2+, Mg2+ and Zn2+ levels has been established in ascitic H3, H2B and H1 fractions.

[Possibility of migration of several elements in biological systems following x-irradiation].

The effect of local X-irradiation on the content of trace elements of subcellular fractions (nuclear, mitochondrial) and the blood serum of rats with sarcoma M-1 was studied. It was shown that systematic local irradiation of sarcoma M-1 (single dose--250 R) during the tumour growth promoted zinc redistribution from the nuclei into the mitochondria. In addition, there were revealed statistically significant postirradiation changes in the blood serum Ca content of rats with sarcoma M-1 after one-time local irradiation of the tumour with 1000 R.