The mechanism of formation of Liesegang structures around Dictyostelium discoideum

A theoretical study of the phenomenon of Liesegang structure formation induced by the Dictyostelium discoideum population in a medium containing folic acid was carried out. Using a "reaction-diffusion" model proposed in this work, it was shown that the formation of Liesegang structures around the Dictyostelium discoideum population depends on two competing processes: (a) inactivation of folic acid by vegetative amoebae and (b) the chemical reaction of folic acid with the products of amoeba metabolism, which results in the formation of insoluble sediment. The dependence of the model solutions on the geometric and functional parameters was studied. The results are in good agreement with experimental data.     

The neuromediator modulation of the ionic composition of the brain cells in rats irradiated at nonlethal doses

It had been found that both the single prolonged irradiation and chronic (fractionated) one with doses of 25 and 50 cGy (1.75 mGy/min) caused essential modification of the biphase modulative effects of acetylcholine and gamma-aminobutyric acid upon K+ level in rat brain cortex slices to be compared to the acute lethal irradiation influence. The results of model experiments showed saturated fatty acids to be significant for the changes in regulative functions of nerve cell membranes after exposure to low dose-rate radiation.     

Physiologo-biochemical properties of a strain of Beijerinckia mobilis 1phi Phn+--a degrader of polycyclic aromatic hydrocarbons

Beijerinckia mobilis 1f capable of degrading polycyclic aromatic hydrocarbons (PAHs) was isolated from a soil contaminated with creosote. Strain 1f could utilize phenanthrene and naphthalene as the sole sources of carbon. The mean rate of phenanthrene degradation during culture growth was 7-8 micrograms/(ml h). After cultivation under nonselective conditions, strain 1f retained its ability to degrade phenanthrene. Cometabolism considerably widened the range of PAHs that could be transformed by strain 1f. The strain was able to grow in a mineral medium with creosote as the sole source of carbon. After 30 days of cultivation in this medium, the total concentration of PAHs decreased from 665.5 mg/l to 170 mg/l.     

Mechanosensitivity of gramicidin A channels in semispherical bilayer membranes at constant tension

Mechanoelectrical transduction in gramicidin A channels was studied in macroscopic planar lipid bilayer membranes bulged at constant tension. We found a supralinear increase in the single channel activity, which was proportional to the square of membrane radius but could not be accounted for by the increase in membrane surface area or by recruitment of new channels. When being extrapolated to biological membranes, these observations may suggest that the activity of permeability of ion channels can be influenced simply by changing the shape of the membrane, with or without stretching.     

Effect of actinomycin D and cycloheximide on lipoproteins in blood serum and liver cytosol of rats under oxidative stress

The influence of protein synthesis inhibitors on rat lipoprotein content and composition under oxidative stress caused by cobalt chloride injection has been investigated in the present work. It has been concluded that apoprotein synthesis is very important process influencing on adaptive reactions under free-radical oxidation activation conditions. Co-administration of cobalt chloride and actinomycin D or cycloheximide (the inhibitors of the protein synthesis) has realy prevented hyperlipoproteinemia in many cases but hasn't influenced on lipoprotein oxidation. Pre-beta- and beta-lipoproteins were discussed to have mRNA pool in hepatocytes.     

Spectral EEG characteristics in emotional stress model in cats

Emotional stress induced a global activation of the brain electrical activity: a decrease in the power of the theta-, alpha-, and beta-1-frequency bands in animals with active behaviour, and a decrease in the power of the theta- and alpha-frequency bands in animals with behavioural inhibition. The findings suggest that two forms of emotional behaviour correspond to different patterns of the brain activity. Appearance of spindle-like activity in passive animals' parietal and occipital leads suggests a hypothetical suppression in associative parietal and visual neocortical areas involved in processing the sensory information.     

Diversity of facultatively anaerobic microscopic mycelial fungi in soils

The numbers of microscopic fungi isolated from soil samples after anaerobic incubation varied from tens to several hundreds of CFU per one gram of soil; a total of 30 species was found. This group is composed primarily of mitotic fungi of the ascomycete affinity belonging to the orders Hypocreales (Fusarium solani, F. oxysporum, Fusarium sp., Clonostachys grammicospora, C. rosea. Acremonium sp., Gliocladium penicilloides, Trichoderma aureoviride, T. harzianum, T. polysporum, T. viride. T. koningii, Lecanicillum lecanii, and Tolypocladium inflatum) and Eurotiales (Aspergillus terreus, A. niger, and Paecilomyces lilacimus), as well as to the phylum Zygomycota, to the order Mucorales (Actinomucor elegans, Absidia glauca, Mucor circinelloides, M. hiemalis, M. racemosus, Mucor sp., Rhizopus oryzae, Zygorrhynchus moelleri, Z. heterogamus, and Umbelopsis isabellina) and the order Mortierellales (Mortierella sp.). As much as 10-30% of the total amount of fungal mycelium remains viable for a long time (one month) under anaerobic conditions.     

Mutational pressure in genomes of alphaherpesviruses infecting human

Genomes of the herpes simplex viruses are extremely enriched with GC. Elevated G+C level in genomes of the simplex viruses is a result of their long-term evolution under the influence of the mutational pressure. We counted the rates of nucleotide substitutions from gene coding major capsid protein (MCP) (G+C = 0.68, 3GC = 0.89) of human simplex virus 1 (HSV-1) to the MCP gene (G+C = 0.70, 3GC = 0.91) of HSV-2 (the first pair of genes) and from the same MCP gene of HSV-1 to the homologous gene (G+C = 0.73, 3GC = 0.99) from cercopithecine herpes virus 16 (the second pair of genes). The rates of transitions from A-T to G-C base pairs increases 2.17-, 3.09-, and 1.27-fold in the first, second, and third codon positions, respectively, if compared those rates between the second and first pair of genes (the growth of GC-richness is only 3%). This effect is due to an approximately 90% GC-richness of the third codon positions in all those genes. Transitions caused by the strong mutational pressure (from A-T to G-C base pairs) have a low probability to occur in the third positions, but high probability to occur in the first and second positions. For MCP gene of human herpes 3, the probability of the occurrence of transition caused by mutational pressure in the third codon position is 2.36 times higher than in MCP gene of HSV1, and 3 times higher than in MCP gene of HSV2. These data could provide an explanation of rarely occurring relapses of herpes Zoster infection and frequently occurring relapses of herpes simplex infection.     

The study of markers of herpes virus infections in myocardial ischemia

A group of patients with ischemic heart disease (IHD), who underwent surgical aorta-coronary vascular shunting, was examined in this investigation. Low titers of HSV-1 specific IgG were detected in all patients, the obtained values being consistent with similar data obtained in healthy subjects of the same age. Negative PCR of HSV-I DNA in blood and biopsy results were obtained. None of the patients demonstrated typical clinical pattern of infectious disease caused by herpes simplex virus. These data are evidence of the absence of the HSV-1 correlation with coronary atherosclerosis in patients with the IHD diagnosis. The significance of HCMV specific IgG titers and HCMV DNA detected in blood plasma in 87.7% cases is probably attributed to existence of connection of HCMV infection markers revealing in patient' blood with IHD diagnosis and coronary atherosclerosis. Besides, the HCMV DNA presence in biopsy taken from myocardium or vascular wall with lesion is revealed in 100% cases. The cytomegalovirus markers in tissue lesions with the help of specific antiserums marked to HSMV recombinant proteins are also revealed in 100% cases. This fact indicates the connection between pathological atherosclerotical process in IHD and cytomegalovirus infection.