Immunological characteristics of the 2-stage method of smallpox vaccination]

As a result of observations carried out on children the authors present immunological characteristics of two-stage smallpox vaccination at different intervals (1 to 60 days) between the injection of inactivated and live vaccine. There proved to be acceleration and intensification of antibody formation after two-stage immunization in comparison with the rutine vaccination. A seven-day interval between the injection of the inactivated and live preparations was recommended on the basis of the data obtained.     

Genetic constructions,hyperexpressing recombinant fragments of cytolethal distending toxin of Aggregatibacter actinomycetemcomitans

Aggregatibacter actinomycetemcomitans is a gram negative bacterium and an infectious agent of human diseases with severe oral and extra oral manifestations. One of the major virulence factors in this microorganism is cytolethal distending toxin (CDT). This toxin consists of three subunits—A, B, and C and is able to disrupt cell cycle by intrinsic DNAse activity of its B-subunit. Due to the fact that this protein can represent an important component of diagnostic, prophylactic and therapeutic preparations, production of CDT subunits in preparative quantities is of considerable practical importance. In the current study we demonstrated that deletion of NH₂-terminal regions from the molecules of CDT-A, -B, or -C resulted in 20–400-fold increase in production of the corresponding subunits. These truncated molecules were used as immunogens to raise monospecific sera, which were shown in western blot to react specifically with the homologous subunits of cytolethal distending toxin.     

The Difference in the Effect of Glutamate and NO Synthase Inhibitor on Free Calcium Concentration and Na+,K+-ATPase Activity in Synaptosomes from Various Brain Regions

The significant increase of free calcium concentration ([Ca²⁺]_i) was found in rat cerebral cortex synaptosomes and hippocampal crude synaptosomal fraction after their exposure to glutamate. But no change of [Ca²⁺]_i was revealed in cerebellar synaptosomes, the slight increase of [Ca²⁺]_i in striatal synaptosomes was not significant. The presence of N^g-nitro-L-arginine methyl ester (L-NAME) in the incubation medium practically prevented the increase of [Ca²⁺]_i initiated by glutamate in cerebral cortex synaptosomes, but not in hippocampal ones. The significant diminution of [Ca²⁺]_i in the presence of this inhibitor was shown in striatal synaptosomes exposed to glutamate. Na⁺,K⁺-ATPase activity is significantly lower in cerebral cortex, striatal and hippocampal synaptosomes exposed to glutamate. L-NAME prevented the inactivation of this enzyme by glutamate. In cerebellar synaptosomes the tendency to the decrease of enzymatic activity in the presence of L-NAME was on the contrary noticed. Thus, the data obtained provide evidence of the protective effect of NO synthase inhibitor in brain cortex and striatal synaptosomes, but not in cerebellar synaptosomes. Synaptosomes appear to be an adequate model to study the regional differences in the mechanism of toxic effect of excitatory amino acids.     

Structure of heliomycin produced by Streptomyces heliomycini and antibiotic 11-98 produced by Streptomyces olivocinereus

The data on UV, 1H NMR and mass spectroscopy confirmed that heliomycin produced by S. heliomycini and antibiotic 11-98 produced by S. olivocinereus were identical with resistomycin. The major minor component produced by S. heliomycini was shown to be resistoflavin which was also confirmed by physicochemical methods.     

Palaearctic gastropod gains a foothold in the dominion of endemics: range expansion and morphological change of Lymnaea (Radix) auricularia in Lake Baikal

In and around the endemic-dominated Lake Baikal, palaearctic species are generally restricted to shallow, sheltered bays and in- and out-flowing river floodplains. However, we observed populations of the palaearctic snail Lymnaea (Radix) auricularia on the steep, rocky littoral of Lake Baikal proper. We compared the morphology of 542 shells sampled from this new habitat with potential source populations from conventional habitats. A size-free Discriminant Analysis indicated a strong morphological differentiation of the newly established populations from their likely sources. The new populations had a more compact shell shape with a wide aperture, which may be advantageous in wave-exposed habitats where a firm attachment to the substrate is needed. Shells from the conventional habitats were more elongated, with a narrow aperture, which may be advantageous in habitats that have a dry period where retreating into the mud is required and water loss should be limited. These results may suggest that selection is acting on shell shape in Lake Baikal. The apparent recent arrival of this pandemic gastropod in a habitat previously dominated by endemics constitutes a potential ecological threat and an alert to possible ecological change.     

Activation of Soluble Acid Invertase Accompanies the Cytokinin-Induced Source–Sink Leaf Transition

Activation of soluble acid invertase by cytokinin was shown using as a model a detached sugar-beet leaf, one half (sink) of which was treated with benzyladenine and the other half (source) of which was sprayed with water. Acid invertase was assumed to mediate the hormone-induced sink properties of the cells. The influx of ¹⁴C-sucrose to the leaf half treated with benzyladenine was induced to much greater extent than that of potassium (⁸⁶Rb). This suggests different pathways or mechanisms of translocation of these substances to the induced sink.