Cytogeography of the Phleum pratense group (Poaceae) in the Carpathians and Pannonia

Cytogeographical variability within the Phleum pratense group in the Carpathians and adjacent part of Pannonian lowland, based on 132 populations analysed by flow cytometry, is described. Only diploid and hexaploid plants were detected among 635 samples from the studied area. Diploids were found to be less frequent (127 plants, 20%) than hexaploids (508, 80%). With the exception of the single pure diploid population, diploids always co-occured with hexaploids (30 localities, 22.7%). The majority of populations (101, 76.5%) consisted of hexaploid plants. Most mixed populations occur in the Western Carpathians (26). In the Eastern Carpathians, mixed populations are much rarer, with three populations in Ukraine and one in Romania. In the Southern Carpathians, only hexaploids occur. The conventional taxonomic concept of the two species, diploid P. bertolonii and hexaploid P. pratense , was followed in spite of their sympatric occurence. Distribution maps based on chromosome number data from previous studies and on ploidy level estimates are given for both species in the studied area. The pattern of different distribution of the two taxa within the Carpathians is discussed.  © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society , 2008, 157 , 475–485.     

Effect of 3-week suspension on sympathetic vasoconstrictor response in rat

One of the main problems arising after gravitational unloading is an orthostatic intolerance leading to failure in supporting the upright posture and performing natural locomotion. Among a number of causes for the orthostatic intolerance the decreased circulating blood volume, increased venous distention, alterations in microcirculation, loss of muscular tonus, and regulatory disturbances could be mentioned. The later cause has been intensively studied recently. The aim of the present study is to examine the alterations induced by simulated gravitational unloading in the reaction of resistance vessels of isolated hind limb to the sympathetic stimuli in rats.     

L-Glutamate oxidase from Streptomyces cremeus 510 MGU: growth media optimization for the enhancement of the producer fermentative activity]

The investigation was devoted to culture conditions optimization aimed to maximum secretion of extracellular L-glutamate oxidase by Streptomyces cremeus 510 MGU. It was shown that Ca ions at the concentration 5-20 mM and 0.1% ammonium sulphate enhanced activity of extracellular enzyme to 4 folds. L-glutamate acid supplement had no effect on enzyme activity. Influence of some bivalent cations and aeration regimes on L-glutamate oxidase activity was investigated. Growth media optimization along with screening of active variants resulted with isolation of the strain with L-glutamate oxidase activity about 2 U/mL Rate of peroxide degradation in the presence of filtrated culture of S. cremeus was determined by chemiluminescence method.     

PDX1: A unique pancreatic master regulator constantly changes its functions during embryonic development and progression of pancreatic cancer

Multifunctional activity of the PDX1 gene product is reviewed. The PDX1 protein is unique in that being expressed exclusively in the pancreas it exhibits various functional activities in this organ both during embryonic development and during induction and progression of pancreatic cancer. Hence, PDX1 belongs to the family of master regulators with multiple and often antagonistic functions.     

Structure dissection of human progranulin identifies well-folded granulin/epithelin modules with unique functional activities

Progranulin is a secreted protein with important functions in several physiological and pathological processes, such as embryonic development, host defense, and wound repair. Autosomal dominant mutations in the progranulin gene cause frontotemporal dementia, while overexpression of progranulin promotes the invasive progression of a range of tumors, including those of the breast and the brain. Structurally, progranulin consists of seven-and-a-half tandem repeats of the granulin/epithelin module (GEM), several of which have been isolated as discrete 6-kDa GEM peptides. We have expressed all seven human GEMs using recombinant DNA in Escherichia coli. High-resolution NMR showed that only the three GEMs, hGrnA, hGrnC, and hGrnF, contain relatively well-defined three-dimensional structures in solution, while others are mainly mixtures of poorly structured disulfide isomers. The three-dimensional structures of hGrnA, hGrnC, and hGrnF contain a stable stack of two beta-hairpins in their N-terminal subdomains, but showed a more flexible C-terminal subdomain. Interestingly, of the well-structured GEMs, hGrnA demonstrated potent growth inhibition of a breast cancer cell line, while hGrnF was stimulatory. Poorly folded peptides were either weakly inhibitory or without activity. The functionally active and structurally well-characterized human hGrnA offers a unique opportunity for detailed structure-function studies of these important GEM proteins as novel members of mammalian growth factors.     

Current features of HIV-infection in St. Petersburg

Dynamics of HIV-infection epidemic in St. Petersburg was analyzed. New features of epidemic process, which were not observed in St. Petersburg earlier, whereas noted in other territories of Russia, were revealed and described.