[Effect of autoinducers of anabiosis for some microorganisms on rat liver mitochondria respiration].

2-(4-Hydroxyphenyl)ethane-1-ol (tyrosol) and 5-n-alkyl(C19,C21)resorcinols produced by some microorganisms as anabiosis autoregulators (factors d1) inhibit the electron transport and uncouple oxidative phosphorylation in the respiratory chain of rat liver mitochondria: a 50% decrease of the respiratory control is caused by 0.32-0.36 mumol of tyrosol or by 0.

[Tyrosol--the autoregulatory d1 factor of the yeast Saccharomyces cerevisiae].

The autoregulatory d1 factor of the yeast, Saccharomyces cerevisiae, that induces the transition of vegetative cells into refractory resting forms, has been isolated from the cell-free culture medium as an individual crystalline compound. It has been shown to be 2-(4-hydroxyphenyl)ethane-1-ol which is also known as tyrosol. When added to the producer culture at 5-15 microM concentration, tyrosol stimulated the endogenous respiration of cells, but inhibited at 20-80 microM concentration.

Membrane-structuring properties of bacterial long-chain alkylresorcinols.

To investigate the mechanism by which 5-n-alkyl(C19-C25)-resorcinols synthesized by certain bacteria of the Azotobacter genus affect the lipid bilayers of cellular membranes, planar bimolecular membranes were formed from these alkyl-resorcinols and from mixtures of those and typical bacterial phospholipids such as phosphatidylethanolamine, phosphatidylglycerol, and diphosphatidylglycerol. The electrical properties and, in some instances, the stability of the prepared membranes have been studied. The alkylresorcinols have been found to associate with phospholipids to form oligomeric and polymeric complexes, thereby giving rise to modifications in the bilayer structure and properties.

[The effect of isomeric alkyl (C19--C25) methoxybenzoquinones on mitochondrial respiration].

The influence of 2-methoxy-6-alkyl(C19-C25)benzoquinones-1,4 and 4-methoxy-6-alkyl(C19-C25)benzoquinones-1,2 on the respiration of isolated rat liver mitochondria has been studied. As a concentration of each of the quinones increased gradually from zero, the rate of the respiration using NAD-dependent substrates firstly increased but then decreased, 1,2-quinones being the more potent inhibitors. Concurrently, the respiratory control of mitochondria was lowered, indicating uncoupling effect of these quinones.

[5-Alkyl(C19-C25) resorcinols as regulators of succinate and NAD-dependent substrate oxidation by mitochondria].

The effect of 5-n-alkyl(C19-C25) resorcinols isolated from Azotobacter chroococcum on the oxidation of succinate and NAD-dependent substrates (glutamate, alpha-ketoglutarate, malate, pyruvate) by rat liver mitochondria was studied, using the polarographic technique. With succinate, the above resorcinol lipids activated to some extent the 2,4-dinitrophenol-decoupled mitochondrial respiration, but markedly suppressed it (up to 95%) in the presence of NAD-dependent substrates. The activating and inhibiting effects correlated with the resorcinol lipid/mitochondrial proteins ratio and were observed, when the lipid concentration in the incubation mixture ranged from 2.

[Azotobacter chroococcum, a producer of a new antifungal antibiotic].

Strain 92 of Azotobacter chroococcum was obtained as result of natural selection. It produces an antibiotic active against phytopathogenic fungi. The antibiotic was isolated from the bacterial mass of the culture with ethanol extraction followed by column and thin-layer chromatography on silica gel.

[Spectrophotometric characteristics of the coccoid forms of actinomycetes].

IR spectra of thw whole cells of the coccoid forms (Mycococcus and Micrococcus) isolated from lithophilous lichen were compared with IR spectra of the collection cultures of Micrococcus and Arthrobacter. Generic spectral characteristics of Mycococcus and Micrococcus are presented. Spectral heterogeneity within the genus Arthrobacter complicates the diagnosis.

[Spectral characteristics of Micropolyspora spp. and of actinomycetes similar to them].

IR spectra of the whole cells of oligosporous actinomycetes were studied. These spectra can be used as an additional criterion during identification of actinomycetes at the generic level, and confirm the heterogeneity of the Micropolyspora genus so that some of its species may be classed as an individual genus (Kalakoutskii et al., 1968; Agre, Dorokhova, 1972).