[Effect of Distant Interactions on Growth and Development of Streptomycetes].

Regulation of streptomycete growth and development by distant interactions of physical nature was shown using a vial-in-vial experimental setup, providing physical isolation of the inducer and detector cultures. Some effects of distant interaction were observed with Streptomyces netropsis proliferating submerged culture as an inducer and a surface culture of the same strain as a detector. The growth rate of the detector strain doubled. Spore germination was stimulated, as was indicated by a 30% increase in the number of colony-forming units (CRU) in the detector culture plated as a spore suspension. The phase variation spectrum also changed, with an increased share of the colonies of the morphotype predominant under the standard conditions.

[Diversity of bacterial forms in ice wedge of the Mamontova Gora Glacial complex (central Yakutiya)].

Electron microscopic investigation of four samples of ancient ice wedge from the Pleistocene glacial complex of Mamontova Gora (Yakutiya, Russia) revealed high diversity of bacteriomorphic particles. Their structural features included the presence of electron-transparent zones, presumably inclusions containing storage compounds, and microenvironment (capsules or external sheaths). These features may be a result of adaptive strategies providing for microbial survival under permafrost conditions. Predominance of rod-shaped forms morphologically resembling coryneform actinobacteria was found. X-ray microanalysis revealed organic origin of bacteriomorphic particles. Some particles were characterized by incomplete spectra of the major biogenic elements, resulting probably from low-temperature damage to the cellular structures. Total numbers of aerobic heterotrophic bacteria determined by plating on nutrient media were comparable to the values obtained for permafrost soils and Arctic ice. Predominance of coryneform actinobacteria was observed. Abundance of these evolutionarily early groups of actinobacteria may indicate the ancient origin of the microflora of the relic frozen rocks.

[Structural organization of the phospholipid constituent of cell membranes from Streptomyces hygroscopicus, as determined from neutron diffraction data].

The nanoparameters of the membrane from actinobacteria have been determined by the method of neutron diffraction on multilamellar lipid membranes. It was found that the repeat distance of a partly hydrated membrane formed from the phosphohpid fraction of Streptomyces hygroscopicus (S. hygroscopicus) is 85.8 +/- 0.5 A at T = 20 degrees C and decreases to 83.5 +/- 0.5 A at T = 40 degrees C. Some lipids are not incorporated into the bilayer and form the liquid micellar phase with micelles of size 54.2 +/- 0.2 A.

[Non-species-specific effects of unacylated homoserine lactone and hexylresorcinol, low molecular weight autoregulators, on the growth and development of bacteria].

We conducted a comparative study of the effects of alpha-amino-gamma-butyrolactone, the common structural element of extracellular microbial regulators of the homoserine lactone (HSL) group, and of 4-n-hexylresorcinol, an autoregulator of the alkylhydroxybenzene (AHB) group, on the growth and development of gram-positive and gram-negative bacteria. We revealed non-species-specific effects of HSL and AHB and characterized their concentration dependencies. The addition of 10(-5)-10(-3) M HSL or 10(-5)-10(-4) M AHB during the exponential growth phase of the cultures grown on balanced media resulted in cell division arrest and accelerated the transition to the stationary phase that culminated in endospore formation in Bacillus cereus, Alicyclobacillus tolerans, and Sulfobacillus thermosulfidooxidans. When bacilli grew under the cultivation conditions that resulted in a low-zero spore percentage, 10(-4)-10(-3) M HSL cancelled the inhibition of spore formation. In the gram-negative bacteria Pseudomonas aurantiaca and Azotobacter vinelandii, AHB at concentrations of 10(-4) to (1.5-2.5) 10(-4) M induced the formation of dormant cells. Studies with the actinobacterium Streptomyces avermitilis revealed that the HSL effect varied depending on the age of the test cultures. The addition of 10(-4) M HSL during the lag phase of a submerged streptomycete culture accelerated its transition to the stationary phase and induced the formation of endospores, the dormant cells that are regarded as alternatives to exospores (conidia). If HSL (3.64 and 4.55 mg per 1cm2 disc) was locally added to a surface S. avermitilis culture, the growing mycelium formed rings that differed in their density, in the extent of the development of aerial mycelium, and in the presence/absence of exospores. Ring-shaped growth of streptomycete mycelia was also induced by 0.075-0.75 mg of AHB; however, unlike HSL, AHB repressed exospore formation. The data on non-species-specific effects of HSL and AHB suggest that they may perform regulatory functions on the microbial community level.

[Coliphages inactivation using chitosan derivatives]. / Inaktivatsiia kolifagov proizvodnymi khitozana.

The effect of chitosan fragments with different degrees of polymerization and the chemical derivatives of chitosan differing in the number of amino groups and total molecule charge on phages T2, T4, and T7 was studied. The interaction of chitosan with bacteriophage particles inactivated them to the extent dependent on the chemical properties of chitosan and its concentration. Phage T2 was found to be most susceptible to inactivation by chitosan. The polycationic nature of chitosan plays an important role in the inactivation of phages. It is assumed that the abnormal rearrangement of the basal plate of phages, the loss of long tail fibers, and probably, modification of the receptor-recognizing phage proteins may be responsible for the inactivation of coliphages by chitosan.

Characterization of bean mild mosaic virus: particle morphology, composition and RNA cell-free translation.

Virions of bean mild mosaic virus (BMMV) are built of 180 subunits of a single protein species of MW 40 x 10(3) [coat protein CP], packed into a T = 3 surface lattice. The capsomers on the five-fold symmetry axes protrude 2-3 nm from the particle surface. The virions encapsidate genome-size [approximately 4,200 nucleotides (nt)] as well as some heterogeneous RNAs of subgenomic size approximately 1,000-2,000 nt. In cell-free systems from Krebs-2 ascites cell extracts and rabbit reticulocyte lysates, genome-size RNA directed the synthesis predominantly of two polypeptides of MW 27 x 10(3) and 79 x 10(3) while the third major BMMV-specific polypeptide (MW 40 x 10(3), putative CP) seemed to be encoded by a shorter messenger RNA. The 'cap' analogue, m7GDP, partially inhibited BMMV RNA in vitro translation, suggesting that at least part of the BMMV-specific RNAs are capped. Oligo (dT)-cellulose column chromatography data suggested that poly(A)-tracts are absent from the BMMV genome. The data obtained confirm the previous classification of BMMV within the carmovirus group.