Immunoelectrophoresis analysis of the antigenic composition of E. coli K12 hybrids which acquired the serological specificity of S. newcastle and S. flexneri

Genetic and immunoelectrophoretic studies confirm earlier data on the presence of 2 specific antigens of acidic nature in S. newcastle; one of them is a specific thermolabile K-antigen responsible for type IV specificity of these bacteria. The data concerning the differences in the genetic determinants controlling the synthesis of O- and K-antigens in S. newcastle have been obtained. S. newcastle O- and K-antigens did not react with S. flexneri in the group serum system 3, 4, which indicates that S. newcastle are serologically isolated and form a separate taxonomic group of dysentery bacteria. The existence of cross reactions between S. flexneri and S. newcastle due to the presence of neutral R-core antigens common to these 2 species has been shown . Immunoelectrophoresis in agar is the most promising and informative method in genetic and chemical studies of the antigenic structure of bacteria.     

NMR study of the state of water in the human lens during cataract development

Water proton spin-spin relaxation times (T2) and the content of bound, "non-freezable" at -9 degrees C water in both normal human lenses and human lenses of different stages of cataract progression (cataracta incipiens, nondum matura, mature hypermatura) were measured by NMR spin echoes method. By the stage of cataracta nondum matura, increase of bound water content and simultaneous, almost half decrease of the relaxation time (T2), were observed. However, on the following stages of cataract evaluation (almost mature, mature cataracts) a gradual decrease of bound water content is noted, but only for the mature cataract stage the water content significantly differs from that of the normal one. On the stage of hypermature cataract the presence of two unexchanged with each other fractions of water is found. The obtained data are explained by lens protein reconstructions during the cataract progression.     

Effect of Metalaxyl on the incidence and severity of Pearl millet downy mildew disease in Northern Nigeria

Pearl millet downy mildew (DM) incidence, severity and yield losses of two pearl millet varieties (local and improved) due to the disease were determined in the field. Significant differences in the disease incidence and severity were recorded in the plots sown with metalaxyl-treated seeds and those sown with non-treated seeds, indicating the efficacy of the fungicide on the fungus. Yield losses due to non-treatment of seeds with metalaxyl was 40.88 and 45.39% in a local variety and 43.00 and 18.60% in an improved variety in the 2000 and 2001 cropping seasons respectively. Significant differences between plots sown with metalaxyl-treated and those sown with non-treated seeds were obtained for other yield components such as 1000-grains weight, panicle length and weight.     

Gene expression and the evolution of phenotypic diversity in social wasps

Background  

Organisms are capable of developing different phenotypes by altering the genes they express. This phenotypic plasticity provides a means for species to respond effectively to environmental conditions. One of the most dramatic examples of phenotypic plasticity occurs in the highly social hymenopteran insects (ants, social bees, and social wasps), where distinct castes and sexes all arise from the same genes. To elucidate how variation in patterns of gene expression affects phenotypic variation, we conducted a study to simultaneously address the influence of developmental stage, sex, and caste on patterns of gene expression in Vespula wasps. Furthermore, we compared the patterns found in this species to those found in other taxa in order to investigate how variation in gene expression leads to phenotypic evolution.     

Systemic organization of functional interhemisphere asymmetry. Mirror asymmetry

The systemic organization of hemispherical asymmetry at the behavioral, neurophysiological, and biochemical levels was studied. An interconnection and hierarchic coordination of the parameters of different levels were revealed, which are confirmed by multiple correlations between them. An interrelation between the processes of peroxidation of brain membrane lipids, the level of direct current potential, and the behavior of animals was shown. A significant difference in correlations between right-hander and left-hander animals was found.     

The Mechanism of Fractal-Like Structure Formation by Bacterial Populations

Three types of population growth and development of chemotaxic motile bacteria Escherichia coli on semi-solid nutrient media are investigated: a) stable development – circular symmetrical waves; b) bursts; c) fractal-like self-organization. Experimental investigation of the burst formation is presented. The microscopic analysis of growing, fractal-like structures is carried out, and a mechanism for such structure formation is suggested. It is supposed that fractal-like bacterial structures growth is based on the principle of successively forming multiple micro-bursts. A mathematical model has been suggested to reproduce the experimental results. The structures obtained by numerical modeling of population growth in the parameter space substrate concentration - bacterial movement rate reproduce the corresponding experimental structures in the space nutrient concentration in the media – the density of the media.     

Biosynthesis of mini-antibodies to human ferritin in plant and bacterial producers

A recombinant scFv antibody against human spleen ferritin was expressed as a barstar-fused protein in Escherichia coli and in Nicotiana tabacum plants and suspension cell cultures. As demonstrated by immunoblotting with antibarstar antibodies, direction of the recombinant protein to the endomembrane system of plant cells ensured its stability and solubility. Production of the recombinant protein did not differ between parental transgenic plants and their first-generation progeny. Fusion with barstar allowed not only immunochemical detection of the recombinant scFv antibody, but also their purification from the plant material by affinity chromatography with barnase-His6 immobilized on a metal-affinity carrier.     

How does environment modify the spatial structure of Dictyostelium discoideum population

The transformation of the spatial structure of a Dictyostelium discoideum population in response to environmental changes induced by this population was investigated. A comparative analysis of the spatial and temporal characteristics of the D. discoideum colony is given for two cases: (a) when the colony is cultivated on a bacterial lawn, i.e. under conditions close to natural, and (b) in the absence of the bacterial lawn when the colony grows on the nutrient substrate enriched with folic acid. It is shown that the environmental changes induced by cell metabolism modify the spatial structure of the D. discoideum population first, the rate of population propagation falls drastically, which correlates with a decrease in the substrate pH; second, the spatial redistribution of the D. discoideum cell density correlates with the redistribution of folic acid in the substrate. The mechanism of the environment impact on the D. discoideum colony transformation is discussed.