Distribution of botulinum toxin-producing clostridia in soils of Argentina

We studied the presence of botulinum toxin-producing clostridia in 2,009 soil samples from five geographical regions of Argentina. The prevalence was 23.5%, and the distribution was not homogeneous among the regions. We observed a great multiplicity of serological types and a higher prevalence in nonvirgin soils than in virgin soils.     

The construction and monitoring of genetically marked, plasmid-containing, naphthalene-degrading strains in soil

A genetically marked, plasmid-containing, naphthalene-degrading strain, Pseudomonas putida KT2442(pNF142::TnMod-OTc), has been constructed. The presence of the gfp gene (which codes for green fluorescent protein) and the kanamycin and rifampicin resistance genes in the chromosome of this strain allows the strain's fate in model soil systems to be monitored, whereas a minitransposon, built in naphthalene biodegradation plasmid pNF142, contains the tetracycline resistance gene and makes it possible to follow the horizontal transfer of this plasmid between various bacteria. Plasmid pNF142::TnMod-OTc is stable in strain P. putida KT2442 under nonselective conditions. The maximal specific growth rate of this strain on naphthalene was found to be higher than that of the natural host of plasmid pNF142. When introduced into a model soil system, the genetically marked strain is stable and competitive for 40 days. The transfer of marked plasmid pNF142::TnMod-OTc to natural soil bacteria, predominantly fluorescent pseudomonads, has been detected.     

Cell wall teichoic acids from Streptomyces daghestanicus VKM Ac-1722T and Streptomyces murinus INA-00524T

The structure of cell wall teichoic acids was studied by chemical methods and NMR spectroscopy in the type strains of two actinomycete species of the "Streptomyces griseoviridis" phenetic cluster: Streptomyces daghestanicus and Streptomyces murinus. S. daghestanicus VKM Ac-1722T contained two polymers having a 1,5-poly(ribitol phosphate) structure. In one of them, the ribitol units had alpha-rhamnopyranose and 3-O-methyl-alpha-rhamnopyranose substituents; in the other, each ribitol unit was carrying 2,4-ketal-bound pyruvic acid. Such polymers were earlier found in the cell walls of Streptomyces roseolus and Nocardiopsis albus, respectively; however, their simultaneous presence in the cell wall has never been reported. The cell wall teichoic acid of Streptomyces murinus INA-00524T was is a 1,5-poly(glucosylpolyol phosphate), whose repeating unit was [-6)-beta-D-glucopyranosyl-(1 --> 2)-glycerol phosphate-(3-P-]. Such a teichoic acid was earlier found in Spirilliplanes yamanashiensis. The 13C NMR spectrum of this polymer is presented for the first time. The results of the present investigation, together with earlier published data, show that the type strains of four species of the "Streptomyces griseoviridis" phenetic cluster differ in the composition and structure of their teichoic acids; thus, teichoic acids may serve as chemotaxonomic markers of the species.     

Physical development of Belarussian children

Anthropological research on children from Minsk was carried out within the framework of medical ecological monitoring. Besides the wide anthropometrical program, a study of the ecological conditions in the areas where the children examined reside and train was carried out. Comparison of the basic parameters of physical development in various age groups and the analysis of annual increases shows intensification of growth among modern children despite some decrease in the rates of acceleration. Some increase in body length and decrease of body weight as well as the reduction of chest circumference is common. Regional studies, particularly in the radiation control zones, show the dependence of physical development on the ecological situation.     

The appraisal of the level of photo- and peroxide resistance of human erythrocytic and lymphocytic cells in presence of biogenic amines

The changes of photo- and peroxide resistance of erythrocytic and lymphocytic cells of human under influence of UV and some active oxygen forms in presence of biogenic amines such as serotonin, dopamine, adrenalin, histamine had been investigated. While investigating the degree of photohemolysis of erythrocytes it was discovered that biogenic compounds raise UV stability of erythrocytic membranes. By using the method of chemiluminescence it was established that biogenic amines increased the degree of peroxide resistance of human erythrocytic and lymphocytic cells. The decrease of the level of erythrocytic diene conjugates under influence of UV by serotonin and histamine was also discovered.     

Programmed cell death and cell extrusion in rat duodenum: a study of expression and activation of caspase-3 in relation to C-jun phosphorylation, DNA fragmentation and apoptotic morphology

The small intestinal epithelium is continuously renewed through a balance between cell division and cell loss. How this balance is achieved is uncertain. Thus, it is unknown to what extent programmed cell death (PCD) contributes to intestinal epithelial cell loss. We have used a battery of techniques detecting the events associated with PCD in order to better understand its role in the turnover of the intestinal epithelium, including modified double- and triple-staining techniques for simultaneously detecting multiple markers of PCD in individual cells. Only a partial correlation between TUNEL positivity for DNA fragmentation, c-jun phosphorylation on serine-63, positivity for activated caspase-3 and apoptotic morphology was observed. Our results show that DNA fragmentation does not invariably correlate to activation of caspase-3. Moreover, many cells were found to activate caspase-3 early in the process of extrusion, but did not acquire an apoptotic nuclear morphology until late during the extrusion process. These observations show that the lack of consensus between different methods for detecting PCD may be explained both by different timing of appearance of PCD markers and, additionally, by the occurrence of different forms of PCD during the normal turnover of cells on small intestinal villi.     

Clone identification and clonal structure of the European aspen (Populus tremula)

The European aspen (Populus tremula) is thought to reproduce mostly asexually. Thus aspen forms clones, in which several ramets belong to one genetically defined genet. We compared the clonal structure of aspen in old-growth and managed forests in southern and northeastern Finland. Clones were identified using morphological characters and nine microsatellite loci originally developed for Populus tremuloides. There were more clones identified by microsatellites than morphotypes both in old-growth and managed forest. The average size of the clones was only 2.3 ramets and most clones (70%) consisted of just one ramet. The size of the clones showed no difference between managed and old-growth forests or between northeastern and southern Finland. The small size of the clones suggests that most of them are relatively young. Therefore, sexual reproduction may be more common than previously thought. There was an aggregated spatial genetic structure as measured by Moran's I (0-10 m) and by co-ancestry (rho(ij), 0-20 m). Low level of co-ancestry can be explained by relatively unrestricted gene flow, the important role of disturbance in reproduction, and/or local selection.     

Features of crossability, haploidy and polyembryony in hybrid combinations between common barley Hordeum vulgare L. (2n = 14) and wheat-rye substitution lines Triticum aestivum L., cultivar Saratovskaya 29/Secale cereale L., cultivar Onokhoiskaya

The role of individual chromosomes of rye in the manifestation of crossability and seedling development in hybrid combinations between common barley Hordeum vulgare L., cultivar Nepolegayushchii (2n = 14) and five wheat-rye substitution lines Triticum aestivum L., cultivar Saratovskaya 29/Secale cereale L., cultivar Onokhoiskaya (2n = 40 wheat + 2 rye chromosomes). Crossability, which was measured by two parameters--frequency of set grains and frequency of grains with embryos--was shown to be significantly affected by each of the five rye chromosomes examined: 1R, 2R, 3R, 5R, and 6R; the development of barley haploids was affected by rye chromosomes 1 R, 3R, and 5R. We were the first to demonstrate that polyembryony could be induced by mutual effects of barley cytoplasm and rye chromosome 1R. Possible mechanisms controlling the development of haploids and twins in hybrid combinations H. vulgare x T. aestivum/S. cereale are discussed. The conclusion is drawn that hybrid combinations between common barley and wheat-rye substitution lines can serve as new models for studying incompatibility mechanisms in distant crosses and genetic control of parthenogenesis.