Use of highly dispersed materials for culturing and isolation of granular Agrobacterium radiobacter preparations ]

The effects of synthetic and natural high-dispersion materials on the growth of Agrobacterium radiobacter were studied. Natural minerals montmorillonite and palygorskite (10 g/l nutrient medium) were more potent than high-dispersion silica and its modified forms in stimulating growth of Agrobacterium radiobacter. The interaction of Agrobacterium radiobacter with clay minerals increased the survival rate of bacteria at supraoptimal temperatures. We elaborated new granular bacterial preparation, which enhanced the productivity of cucumbers by 12-15%.     

Dynamics of the reversible transition of Vibrio cholerae into the uncultivable state in the presence of organic and inorganic microcosmic components

The dynamics of the transition of V. cholerae into the uncultivable state in distilled, river and tap water, containing organic and inorganic components added, was studied. As additives, potassium nitrate, potassium phosphate, magnesium sulfate, ammonium chloride, lysine, alpha-ketoglutarate, succinic acid, catalase were used. The study of the influence of biotic factors on transition into the uncultivable state was carried out in the presence of one-celled green algae Scenedesmus quadricauda or infusoria Paramecium caudatum. The linear dependence of speed of transition into the uncultivable form on the concentration of cells was noted. The composition of the microcosmic medium was also found to have some influence on the speed of transition into the uncultivable form and on the reversibility of this process. The presence of organic substances, such as peptone solution or destroyed cells of phyto- and zooplankton, in the microcosmic medium prolonged the time of transition into the uncultivable form and produced a positive effect on the capacity of the population to reversion. In respect of live biotic components, no such dependence was found. Inorganic additives prolonged the time of transition into the uncultivable state, but did not promote reversion.     

The dependence of the antibacterial effect of the polycationic peptide warnerin on the energy state of target cells

The bactericidal effect of the polycationic peptide warnerin, produced by Staphylococcus warneri IEGM KL-1, was found to depend on the energy state of susceptible Staphylococcus epidermidis cells. The pretreatment of these cells with compounds that diminish the proton-motive force of plasma membranes enhanced cell tolerance to warnerin. The components and pH of the membrane proton potential influenced the antibacterial activity of warnerin in different ways. In particular, the antibacterial activity of warnerin decreased when the electric component of the proton-motive force of target membranes declined.__________Translated from Mikrobiologiya, Vol. 74, No. 2, 2005, pp. 166–171.Original Russian Text Copyright © 2005 by Korobov, Titova, Lemkina, Polyudova, Pankova.     

The dependence of the antibacterial effect of the polycationic peptide warnerin on the energy state of target cells

The bactericidal effect of the polycationic peptide warnerin, produced by Staphylococcus warneri IEGM KL-1, was found to depend on the energy state of susceptible Staphylococcus epidermidis cells. The pre-treatment of these cells with compounds that diminish the proton-motive force of plasma membranes enhanced cell tolerance to warnerin. The components deltapsi and deltapH of the membrane proton potential influenced the antibacterial activity of warnerin in different ways. In particular, the antibacterial activity of warnerin decreased when the electric component of the proton-motive force of target membranes declined.     

Novel mitochondria-targeted compounds composed of natural constituents: Conjugates of plant alkaloids berberine and palmatine with plastoquinone

Novel mitochondria-targeted compounds composed entirely of natural constituents have been synthesized and tested in model lipid membranes, in isolated mitochondria, and in living human cells in culture. Berberine and palmatine, penetrating cations of plant origin, were conjugated by nonyloxycarbonylmethyl residue with the plant electron carrier and antioxidant plastoquinone. These conjugates (SkQBerb, SkQPalm) and their analogs lacking the plastoquinol moiety (C10Berb and C10Palm) penetrated across planar bilayer phospholipid membrane in their cationic forms and accumulated in isolated mitochondria or in mitochondria in living human cells in culture. Reduced forms of SkQBerb and SkQPalm inhibited lipid peroxidation in isolated mitochondria at nanomolar concentrations. In isolated mitochondria and in living cells, the berberine and palmatine moieties were not reduced, so antioxidant activity belonged exclusively to the plastoquinol moiety. In human fibroblasts, nanomolar SkQBerb and SkQPalm prevented fragmentation of mitochondria and apoptosis induced by exogenous hydrogen peroxide. At higher concentrations, conjugates of berberine and palmatine induced proton transport mediated by free fatty acids both in model and in mitochondrial membrane. In mitochondria this process was facilitated by the adenine nucleotide carrier. As an example of application of the novel mitochondria-targeted antioxidants SkQBerb and SkQPalm to studies of signal transduction, we discuss induction of cell cycle arrest, differentiation, and morphological normalization of some tumor cells. We suggest that production of oxygen radicals in mitochondria is necessary for growth factors-MAP-kinase signaling, which supports proliferation and transformed phenotype.     

Characteristics of disturbances of intercortical and cortical-subcortical integration in various clinical forms of neurotic depression

Cross-correlation, coherent, and factor analyses of the EEG were used to detect disturbances of spatial organization of brain bioelectric activity, with certain specific features determined by concomitant anxiety and asthenia syndromes in 20 patients with various clinical forms of neurotic depression. In the group of patients with dominance of the depressive syndrome without marked symptoms of asthenia or anxiety, opposite changes in the anterior areas of the right and left hemispheres were found; the interregional relationships of the EEG of anterior areas of the right hemisphere were decreased as compared to the norm, while the normal level of systemic interaction of bioelectric potentials of the cortex of the left hemisphere was increased. In patients with the depressive syndrome combined with increased anxiety, as well as in patients with distinct asthenic symptoms, a considerable decrease in the level of interregional interactions of bioelectric potentials in frontal regions of the cortex of both hemispheres was detected. This was accompanied by an increase, as compared to the norm, of the level of distant relationships of the EEG in posterotemporal, parietal, and occipital regions. The data indicate that, in the case of neurotic depression, irrespective of concomitant anxiety and asthenia syndromes, there is transient inhibition of the functional activity of frontal regions along with an increased rigidity of systemic interactions of the posterior regions of the cortex of both hemispheres. This suggests that neurotic depression is accompanied by dysfunction of intercortical and cortical-subcortical integration, which causes a disturbance of the systemic organization of ordered interactions of the activity of the anterior and posterior regions of both hemispheres, with certain specific features in patients of each group.     

Effects of long-term fixation on histological quality of undecalcified murine bones embedded in methylmethacrylate

While long-term fixation and storage of specimens is common and useful for many research projects, it is particularly important for space flight investigations where samples may not be returned to Earth for several months (International Space Station) or years (manned mission to Mars). We examined two critical challenges of space flight experimentation: the effect of long-term fixation on the quality of mouse bone preservation and the preservation of antigens and enzymes for both histochemical and immunohistochemical analyses, and how the animal/sample processing affects the preservation. We show that long-term fixation minimally affects standard histological staining, but that enzyme histochemistry and immunolabeling are greatly compromised. Further, we demonstrate that whole animal preservation is not as suitable as whole leg or stripped leg preservation for long-term fixation and all histological analyses. Overall, we recommend whole leg processing for long-term storage of bone specimens in fixative prior to embedding in plastic for histological examination.     

Epidemiological and immunological study of the foci of measles infection

Anamnestic data in respect to measles failed to correspond to the results of serological examination of contacts at the foci of the given infection. The collective immunity level in children's institutions is inadequate for the prevention of measles outbreaks. The incidence of the disease depended both on the level of immunity among the children and on the duration of presence of the source of infection in the focus. Live measles vaccine protected 90 percent of the vaccinated children from contracting the disease in the foci. At the very beginning of the postvaccinal period immunization defects were revealed in 26.5 percent of the vaccinated children who fell ill with measles. Morbidity index among the vaccinated individuals constituted 3.8 percent. One of the causes of measles contraction by the vaccinated individuals was the loss of postvaccinal immunity. Systematic control over the antimeasles immunity level with the aid of serological investigations is necessary for the purpose of detection of persons sensitive to measles in children's collective bodies.