Plant virus infection development as affected by heavy metal stress

The work was focused on the investigation of possible dependencies between the development of viral infection in plants and the presence of high heavy metal concentrations in soil. Field experiments have been conducted in order to study the development of systemic tobacco mosaic virus (TMV) infection in Lycopersicon esculentum L. cv. Miliana plants under effect of separate salts of heavy metals Cu, Zn and Pb deposited in soil. As it is shown, simultaneous effect of viral infection and heavy metals in tenfold maximum permissible concentration leads to decrease of total chlorophyll content in experiment plants mainly due to the degradation of chlorophyll a. The reduction of chlorophyll concentration under the combined influence of both stress factors was more serious comparing to the separate effect of every single factor. Plants' treatment with toxic concentrations of lead and zinc leaded to slight delay in the development of systemic TMV infection together with more than twofold increase of virus content in plants that may be an evidence of synergism between these heavy metal's and virus' effects. Contrary, copper although decreased total chlorophyll content but showed protective properties and significantly reduced amount of virus in plants.     

Dissociative mechanism of thermal denaturation of rabbit skeletal muscle glycogen phosphorylase b

The thermal stability of rabbit skeletal muscle glycogen phosphorylase b was characterized using enzymological inactivation studies, differential scanning calorimetry, and analytical ultracentrifugation. The results suggest that denaturation proceeds by the dissociative mechanism, i.e., it includes the step of reversible dissociation of the active dimer into inactive monomers and the following step of irreversible denaturation of the monomer. It was shown that glucose 1-phosphate (substrate), glucose (competitive inhibitor), AMP (allosteric activator), FMN, and glucose 6-phosphate (allosteric inhibitors) had a protective effect. Calorimetric study demonstrates that the cofactor of glycogen phosphorylase-pyridoxal 5'-phosphate-stabilizes the enzyme molecule. Partial reactivation of glycogen phosphorylase b preheated at 53 degrees C occurs after cooling of the enzyme solution to 30 degrees C. The fact that the rate of reactivation decreases with dilution of the enzyme solution indicates association of inactive monomers into active dimers during renaturation. The allosteric inhibitor FMN enhances the rate of phosphorylase b reactivation.     

Comparative cytogenetics of hamsters of the genus Calomyscus

Karyotypes of Calomyscus from different regions of Turkmenistan, Iran, and Azerbaijan were studied using chromosome banding (G- and C-banding) and analyses of meiosis in laboratory hybrids. Extensive variation in the diploid number and the number of autosomal arms (FNa) was revealed (2n = 30, FNa = 44; 2n = 32, FNa = 42; 2n = 44, FNa = 46; 2n = 44, FNa = 58; 2n = 37, FNa = 44; 2n = 50, FNa = 50; 2n = 52, FNa = 56). Centric and tandem fusions and heterochromatin changes were identified as the major modes of karyotype evolution in this group. Natural hybrids between individuals with different karyotypes were recorded, and regular chromosome pairing in meiosis was observed in laboratory hybrids. Fluorescence in situ hybridization with a 353-bp BspRI complex tandem repeat indicated that chromosomal repatterning occurred recently within the genus. There is no unequivocal evidence suggesting the role of chromosomal change in the speciation of the populations of Calomyscus examined.     

Extramedullary hematopoiesis in a case of benign mixed mammary tumor in a female dog: cytological and histopathological assessment

Backgroud  

Extramedullary hematopoiesis (EMH) is defined as the presence of hematopoietic stem cells such as erythroid and myeloid lineage plus megakaryocytes in extramedullary sites like liver, spleen and lymph nodes and is usually associated with either bone marrow or hematological disorders. Mammary EMH is a rare condition either in human and veterinary medicine and can be associated with benign mixed mammary tumors, similarly to that described in this case.     

Relations between the methods of isolating Brucella lipopolysaccharides and their effect on hemopoiesis in mice

The comparative study of the effect produced by different lipopolysaccharide (LPS) preparations obtained from B. melitensis virulent strain 565 and B. abortus vaccine strain 19-BA on hematopoiesis in mice was made. The LPS preparations were obtained (1) by Boivin's technique, (2) by Westphal's technique and (3) by mild alkaline hydrolysis of Bovin's active complex, this technique having been developed at the Brucellosis Laboratory of the Gamaleya Research Institute of Epidemiology and Microbiology. All tests (the spleen endocolonization test, the hydroxyurea kill test, the determination of the content of splenic colony-forming units in the peripheral blood) showed that LPS from B. melitensis virulent strain 565 had a more pronounced disturbing effect on hematopoiesis than LPS from B. abortus vaccine strain 19-BA. Among the LPS preparations obtained by different methods, the one obtained with the use of the technique developed at the Gamaleya Research Institute of Epidemiology and Microbiology proved to have the mildest effect on hematopoiesis, probably due to the partial saponification of the lipid component of LPS. Lipid A in a dose of 0.1-10 micrograms produced no activating effect on the hematopoiesis characteristics under study. None of the LPS preparations proved to be capable of stimulating the formation of transitory endogenous colonies in the spleen of mice.     

Genetic diversity of Chionomys genus (Mammalia, Arvicolinae) and comparative phylogeography of snow voles

In the present study, the genetic polymorphism of the Chionomys genus was examined based on the sequencing of the mitochondrial cytb gene and two nuclear exons, including GHR exon 10 and BRCA1 exon 11. The distinct subdivision of the genus of snow voles into five lineages, including Ch. nivalis, Ch. gud, Ch. roberti, and Ch. aff. nivalis from Turkey, as well as Ch. aff. gud from Turkey, was demonstrated. The branching order in the trees constructed based on the data for different genes was ambiguous, which was probably the consequence of recent and rapid radiation of the major lineages from a common ancestor. However, the data of the mitochondrial and nuclear gene analyses definitely indicated that the genetic and taxonomic diversity of the Chionomys genus was higher than it was expected before. The genetic divergence of some populations was so deep that they probably deserved the statuses of independent species. Despite that the range of the European snow vole Ch. nivalis is larger and more fragmented than the Gudaur vole Ch. gud, the latter species with its relatively small range, which is limited to the Caucasian and Pontic Mountains, was characterized by a similarly expressed phylogenetic structure. At the same time, Robert’s vole Ch. roberti was less structured genetically than the first two species. The data obtained supported the Near Eastern, rather than the European origin of the Chionomys genus.     

Bacterial endotoxinemia in children with intestinal dysbacteriosis

34 children with gastrointestinal diseases of infectious, allergic and mixed etiology were examined. The state of normal microflora in the large intestine as indicated by fecal bacterial charts and the level of secretory immunoglobulin A (sIgA) in the contents of the intestine as indicated by the results of radial immunodiffusion were studied. In addition, the content of endotoxin in the children's plasma was determined with the use of the Limulus (LAL) test. The presence of endotoxin in the plasma of children with intestinal dysbiosis was determined in 71.1% of cases. The frequency of the detection of antigenemia was found to be related to the severity of manifestations of dysbiotic changes in the intestine and to the level of sIgA in fecal supernatants. The inclusion of the probiotic preparation Bifidumbacterin forte containing live bifidobacteria adsorbed on activated charcoal into the complex therapy of digestive tract diseases ensured a decrease in the detection rate of endotoxinemia, which correlated with the tendency towards the normalization of defective intestinal microflora.