Occurrence of Helicobacter pylori specific antigens in diseases of gastrointestinal tract

The results of the immunophoretic analysis of H. pylori antigenic structure are presented. Along with H. pylori O-antigen, specific surface antigen of acidic nature, relatively thermolabile with characteristics similar to those of K-antigens, was detected. A diagnosticum based on the coagglutination test for the rapid detection of H. pylori specific antigens in the patients' biological fluids (coprofiltrate, saliva) by the noninvasive method was developed. The circulation mode of H. pylori in human body and its correlation with the clinical symptoms of the disease was shown. H. pylori antigens were very frequently detected (in 65 - 83% of cases) in patients with acute bacterial enteric infections: shigellosis, salmonellosis, yersiniosis, campylobacteriosis. The newly developed method seems to be promising for the rapid diagnosis of H. pylori associated infections, for the prolonged monitoring and evaluation of the effectiveness of antibacterial therapy.     

A simulation model of <Emphasis Type="Italic">Escherichia coli</Emphasis> osmoregulatory switch using E-CELL system

Background  

Bacterial signal transduction mechanism referred to as a "two component regulatory systems" contributes to the overall adaptability of the bacteria by regulating the gene expression. Osmoregulation is one of the well-studied two component regulatory systems comprising of the sensor, EnvZ and the cognate response regulator, OmpR, which together control the expression of OmpC and OmpF porins in response to the osmolyte concentration.     

Effect of carbohydrates in the culture medium on amino acid composition of a cephalosporin C producer

The intracellular and extracellular amino acid composition of an auxotrophic methionine-deficient strain of Acremonium chrysogenum was studied in respect of the content of various carbohydrates in the fermentation medium. In the presence of glucose, an intensive involvement of exogenous DL-methionine into the cell metabolism was observed at earlier stages than in the presence of dextran or succrose. The total content of intracellular amino acids was lower in the cells grown on the medium with glucose. The production of cephalosporin C depended on the intracellular content of methionine, glutamic acid and lysine.     

Yellow laccase from the fungus Pleurotus ostreatus D1: purification and characterization

Yellow laccase was isolated from a solid-phase culture of the fungus Pleurotus ostreatus D1 and characterized. It is a copper-containing enzyme with molecular weight 64 kDa. Its absorption spectrum lacks the maximum at 610 nm, characteristic of fungal laccases and corresponding to type I copper atom. The optimum pH values for the enzyme were determined. They proved to be: 7.0 for syringaldazine, 8.0 for pyrocatechol, and 4.0 for 2,2'-azine-bis-(3-ethylbenzothiazoline-6-sulfonate and 2,6-dimethoxyphenol. Kinetic parameters (Km and Vmax) for oxidation of these substrates were determined. The effect of inhibitors (SDS, 2-mercaptoethanol, and EDTA) on the activity of the enzyme was studied. It was shown that yellow laccase from Pleurotus ostreatus D1 oxidized anthracene to anthraquinone by 95% without any mediator.     

A steady state analysis indicates that negative feedback regulation of PTP1B by Akt elicits bistability in insulin-stimulated GLUT4 translocation

Background  

The phenomenon of switch-like response to graded input signal is the theme involved in various signaling pathways in living systems. Positive feedback loops or double negative feedback loops embedded with nonlinearity exhibit these switch-like bistable responses. Such feedback regulations exist in insulin signaling pathway as well.     

Structure of the interphase chromatin in the peripheral blood cells of children with acute lympholeukemia and in their healthy parents

It has been shown using labelled modified AO cytofluorometry of DNP cellular thermal denaturation that the melting profiles of peripheral blood cellular chromatin in children with acute lympholeukemia (ALL) were of strictly individual, "unclassifiable" nature and were similar to those of their mothers but different from those of their fathers and healthy people, which seems in favour of a possible connection between the disease under study and the peculiarities of the mother's genotype. Similar types of deviations have been found in the structure of interphase chromatin of healthy parents of children with ALL. Such a combination of changes in the parents' genotype may prove unfavourable, increasing the birth rate of neonates with a genetic predisposition to the disease in question.     

Influence of carbon sources on the biological activity and morphology of Bacillus thuringiensis parasporal crystals]

The influence of the carbon source on biological activity and morphological properties of the parasporal crystals of Bacillus thuringiensis subsp. kurstaki cultivated on three different media has been studied. Biological activity of delta-endotoxins contained in crystals was tested according to their impact on insects and microorganisms. Variations in carbon sources composition resulted in changes of biological activity and morphology of crystals, caused by alterations in synthesis rate of various delta-endotoxins contained in the crystals. Variations in the content of a certain carbon source (e.g. starch) in the medium produced no effect on the crystals properties, and the content variations of the delta-endotoxins content was proportional to the producer biomass. Control of the antibacterial effect of delta-endotoxins allows a valid evaluation of their biological activity under various growth conditions as well as comparison of the biological potential of entomopathogenic chemicals for plant protection containing delta-endotoxins with different specificity of insecticidal activity.     

Production and antineoplastic activity of new asymmetric azines on the rubomycin base

New alkulidene hydrazones of rubomycin (daunorubicin) with the linear or branched chain of the carbon atoms were studied: rubomycin 13-(hexylidene-2")-hydrazone, rubomycin 13-(heptylidene-3")-hydrazone and rubomycin 13-(4"-methylpentylidene-2")-hydrazone. Alkylidene hydrazones of the formamidine derivatives were also studied: 13:cyclohexylidene hydrazone of 3'-desamino-3'-dimethylformamidine rubomycin and 13-(5"-oxypentyliden-2") hudrazone of 3'-desamino-3'-dimethylformamidine rubomycin. The latter two alkylidene hydrazones were modified twice. It was found that after a single intravenous administration to tumor-free mice the new substance had the same or lower toxicity as compared to that of rubomycin. Antitumor activity of the substances against lymphosarcoma LIO-I was studied comparatively with that of the initial rubomycin. It was shown that the molecule modification at C-13, as well as simultaneous modification at C-13 and the sugar amino group resulted in lowering of the antitumor activity in comparison to that of the starting rubomycin.     

Analysis of optimal phenotypic space using elementary modes as applied to Corynebacterium glutamicum

Background  

Quantification of the metabolic network of an organism offers insights into possible ways of developing mutant strain for better productivity of an extracellular metabolite. The first step in this quantification is the enumeration of stoichiometries of all reactions occurring in a metabolic network. The structural details of the network in combination with experimentally observed accumulation rates of external metabolites can yield flux distribution at steady state. One such methodology for quantification is the use of elementary modes, which are minimal set of enzymes connecting external metabolites. Here, we have used a linear objective function subject to elementary modes as constraint to determine the fluxes in the metabolic network of Corynebacterium glutamicum. The feasible phenotypic space was evaluated at various combinations of oxygen and ammonia uptake rates.     

Synthesis and antitumor properties of 3'-desamino-3'-dimethylformamidinorubomycin

Interaction of rubomycin (daunorubicin) chlorhydrate with dimethylformamidine diethyl acetal yielded 3'-desamino-3'dimethylformamidinorubomycin chlorhydrate (DFR). Comparative antitumor activity of DFR and rubomycin was studied on mice with respect to ascitic lymphadenosis NK/Ly and Ehrlich carcinoma, hemocytoblastosis La, leukemia P-388 and two solid tumors i. e. lymphosarcoma LIO-I and sarcoma 180. The highest antitumor effect of DFR was observed in the mice with Ehrlich carcinoma and lymphadenosis NK/Ly after the drug intravenous administration for 4 times. By selectivity of the antitumor effect DFR was inferior to rubomycin with respect to lymphosarcoma LIO-I and sarcoma 180. It was shown that the antileukemic activity of DFR and rubomycin with respect to hemocytoblastosis La was practically the same. In the experiments with leukemia P-388 DFR was inferior to rubomycin.