Adaptogenic effects of furostanol glycosides of <Emphasis Type="Italic">Dioscorea deltoidea</Emphasis> wall on oxidative processes in tomato plants during biotic stress

The effect of furostanol glycosides of a cell culture of Dioscorea deltoidea Wall on oxidative processes in tomato plants subjected to invasion with the gall nematode Meloidogyne incognita Kofoid et White was studied. We showed that furostanol glycosides induce a nonspecific defensive response in plants. Exposure of cell membranes to furostanol glycosides causes rearrangements in fatty acids, resulting in the formation of conjugated dienes, which makes molecules thermodynamically more stable under stress conditions. The study of changes in the activity of peroxidases of intact plants and plants affected with the nematode, which were treated with furostanol glycosides, showed that the protective effect of the guaiacol-dependent peroxidase is more long-term than the effect of the benzidine-dependent peroxidase.__________Translated from Prikladnaya Biokhimiya i Mikrobiologiya, Vol. 41, No. 3, 2005, pp. 347–353.Original Russian Text Copyright © 2005 by Vasileva, Vanyushkin, Zinoveva, Udalova, Volkova, Nosov, Paseshnichenko.     

Induction of immune response by synthetic fragments of the bovine prion protein and their analogues in mice of various lines

The antibodies to the bovine prion protein were produced by immunizing mice of three lines with five synthetic fragments of the protein and their six analogues. The analogues contained the amino acid substitutions that, according to theoretical calculation, should lead to an increase in the immunogenic activity of peptides. All the peptides, except for one, induced the formation of antibodies. All the sera containing the antipeptide antibodies were tested by an immunohistochemical method. The sera that were effectively bound to the brain preparations from the bovine with spongiform encephalopathy were identified; it was shown that they do not interact with the preparations of normal brain. Therefore, it was shown that the immunization of mice with the synthetic fragments of a prion protein helps obtain specific antibodies suitable for the study and diagnostics of prion diseases.     

Effect of deuteration on methanol dehydrogenase activity in Methylophilus sp. B-7741

We studied the effect of deuterium oxide present in the medium on the activity of methanol dehydrogenase (EC 1.1.99.8) from methylotrophic bacteria Methylophilus sp. B-7741. Methanol dehydrogenase activity in extracts of the biomass obtained in a highly deuterated medium (2H-enzyme) was 34-47% of enzyme activity in the control biomass, which depended on reaction conditions. The isotopic effects of substrate deuterium (methanol) for 1H-enzyme and 2H-enzyme were 1.37 +/- 0.05 and 1.38 +/- 0.01, respectively. We revealed for the first time the reverse isotopic effect of solvent deuterium in the reaction catalyzed by methanol dehydrogenase (0.80 +/- 0.02 and 0.60 +/- 0.01 for 1H-enzyme and 2H-enzyme, respectively).     

Sindbis virus with a tricomponent genome

We established a system for propagation of Sindbis virus (SIN)-based replicons in tissue culture in the form of a tricomponent genome virus. Three RNA fragments containing complementing genetic information required for virus replication are packaged into separate viral particles, and each cell produces at least 1,000 packaged replicons and the number of packaged helpers sufficient to perform the next passage. This system can be used to generate large stocks of packaged replicons. The formation of infectious recombinant SIN virus was not detected in any experiments. These features make multicomponent genome SIN an attractive system for a variety of research and biotechnology applications.     

Mid- and late-Holocene vegetation history,climate and human impact in the forest-steppe ecotone of European Russia: new data and a regional synthesis

Appropriate management of contemporary environments requires knowledge of their long-term history. We use palaeoecological data to explore how contemporary forest-steppe environments have been shaped by climate change and human impacts through the Holocene using the western Mid-Russian Upland as a case-study. Our paper presents new reconstructions of Mid- and Late Holocene climate, vegetation dynamics and local environmental change based on pollen, plant macrofossil and testate amoeba records from a site at Selikhovo (Mid-Russian Upland, Russia). Eutrophic fen vegetation dominated by Phragmites australis developed around 6800 cal year BP and has been resilient to episodes of local burning and variable input of mineral material through the Holocene. New and previously-published data show that the boundary between broadleaf forest and steppe occupied a similar position to present during the period 7000–4800 cal year BP, despite a warmer and drier climate, but shifted to the south following climate cooling and an increase in precipitation from 4800–2500 cal year BP. A subsequent decline in woodland cover was caused by both climate change and human impacts, with human activity becoming increasingly significant over the last two millennia. Prior to major human disturbance (about 1700 cal year BP) the landscape was dominated by mixed broadleaf-pine forests with some spruce covering about 60 % of the study area. Our results emphasize the variability of steppe-forest habitats over long time periods and the need to consider human impacts and climate change when setting targets for habitat conservation.     

The possibility of the germination of spores of pathogenic clostridia and bacilli in soil

A possibility of germination of clostridia (Cl. tetani and Cl. perfringens) and bacilli (Bac. anthracis, STI vaccine strain) has been studied in model experiments with native soil. Mature spores did not germinate upon contact with native soil of deferent agrochemical types. Addition of meat-pepton medium and other protein, amino acid, and sugar-containing media led only to "swelling" of spores. The data obtained support the conclusions drawn by many researches that pathogenic clostridia and bacilli do not germinate in soil.     

Structural-functional characteristics of argiopine--the ion channel blockers from the spider Argiope lobata venom

Argiopine, a compound capable of blocking the glutamate-activated ion channels in experiments with glutamatergic synapses of blowfly larvae, was isolated from the venom of spider Argiope lobata. Argiopine-receptor complex has KD 6,7 X 10(-7) M. The venom solution was treated with 60% ethanol, centrifuged and supernatant was subjected to reversed-phase HPLC in the acetonitrile concentration gradient. Argiopine structure was established using 1H- and 13C-NMR spectroscopy, mass spectrometry, elemental and amino acid analyses. Argiopine (molecular mass 636) consists of arginine (free alpha-NH2) linke with polyamine--NH (CH2)3NH(CH2)3NH(CH2)5NH--through a peptide bond. The polyamine is connected to the alpha-carboxyl group of asparagine whose alpha-amino group is linked to 2,4-dihydroxyphenylacetic acid.     

The effect of carbohydrates on the sporogenesis of Clostridium perfringens and Bacillus anthracis

The authors studied the effect of a number of carbohydrates on the sporogenesis of Clostridium perfringens and Bacillus anthracis (vaccine strain STI) as probable soil factors capable of influencing the duration of survival of these causative agents in the external environment. Differences in the effect of the same sugars on the formation of spores by these microorganisms and clearly expressed sporogenesis-inhibiting effect of glucose (and also of lactose in clostridia) have been demonstrated. The analysis of the peculiarities of sporogenesis under unadjusted and stabilized pH values provides a basis for regarding the "glucose effect" as repression of sporogenesis in the given causative agent, but not as inhibition resulting from considerable acidification of the culture medium. This is essential for the soil conditions characterized by high buffer capacity. The ecological value of substances of carbohydrate nature consists in their important role in the energetics and trophicity of microbial coenoses of the soil which cannot fail reflecting on the fate of pathogenic microorganisms in the soil.