Inhibition of Apoptosis is a Potential Way to Improving Ischemic Brain Tolerance in Combined Exposure to Hypercapnia and Hypoxia.

We compared the intensity of apoptosis in the peri-infarction area of the brain after isolated and combined exposure to hypoxia and hypercapnia prior to focal ischemic stroke modeling. Hypoxia and hypercapnia reduced the number of TUNEL-positive cells in the peri-infarction area, and their combination was most effective in comparison with effects of isolated exposures. The maximum neuroprotective effect of combined exposure to hypoxia and hypercapnia in comparison with isolated exposures was determined by inhibition of apoptosis in the peri-infarction zone.

[Calcium ions in the life cycle of Streptomyces albogriseolus 444]. / Iony kal'tsiia v zhiznennom tsikle Streptomyces albogriseolus 444.

The influence of Ca2+ on the growth, antibiotic production and differentiation of Streptomyces albogriseolus 444 was studied. Consumption of the calcium ions by the strain was followed up. It was shown that Ca2+ changed the dynamics of the biomass accumulation and had no significant effect on the antibiotic production. Calcium present in the medium was assimilated more intensively during the first 24 hours of the strain growth. The own antibiotic nigericin exogenously added to the medium increased the calcium assimilation. In the presence of Ca2+ the nigericin stimulation of the strain differentiation was higher.

[Physiological role of extracellular proteases and calcium ions in the processes of differentiation and antibiotic production by Streptomyces albogriseolus 444]. / Fiziologicheskaia rol' vnekletochnykh proteaz i ionov kal'tsiia v protsessakh differentsiatsii i antibiotikoobrazovaniia Streptomyces albogriseolus 444.

The extracellular proteolytic activity of Streptomyces albogriseolus 444 was investigated. S. albogriseolus 444 was shown to synthesize an extracellular proteolytic complex with metal-protease and trypsin-like activity defining differentiation of the substrate mycelium to the aerial one as well as the spore formation. The synthesis of the complex proceeded in the absence of the inductor in the medium i.e. constitutively. The complex heterogeneity was confirmed chromatographically. Low concentration of calcium ions (1.5 mM) stimulated the total caseinolytic activity and suppressed the activity of the trypsin-like proteases.