[The results of monitoring enterovirus circulation circulation among the population and in the environment of Tula Province over 10 years (1985-1994)]. / Rezul'taty monitoringa za tsirkuliatsiei énterovirusov sredi naseleniia i v okruzhaiushchei srede Tul'skoi oblasti za 10 let (1985-1994).

The study of the isolation rate of polioviruses and other enteroviruses in patients with different diagnosed diseases, among healthy child population, as well as the circulation of these viruses in the environment was carried out on the territory of Tula Province for the period of 1985-1994. The epidemiological analysis of the data obtained in this study are presented. The study revealed that the vaccinal prophylaxis of poliomyelitis, carried out for the period of many years, did not lead to the elimination of poliovirus strains, differing in their genetic properties from vaccine strains, on the territory of Tula Province. A decrease in the immune stratum with respect to polioviruses of types I, II and III, observed in 1985-1994, was accompanied by the circulation of polioviruses of these three types among the population.

[Properties, production, and practical uses of alkaline phosphatase]. / Svoistva, poluchenie i prakticheskoe primenenie shchelochnoi fosfatazy.

Literary data concerning the properties, isolation, purification and practical applications of alkaline phosphatase isolated from different sources are reviewed with special reference to the macromolecular structure and action mechanism of the enzyme in the reactions of phosphomonoester hydrolysis. The practicality of alkaline phosphatase as a helpful tool in conducting enzyme-linked immunoassays is demonstrated.

[The effect of composition and ionic strength of external solution on the aspartate-ammonia lyase and fumarate hydratase activity in Escherichia coli cells]. / Vliianie sostava i ionnoi sily vneshnego rastvora na aktivnost' aspartat-ammiak-liazy i fumarat-gidratazy v kletkakh Esherichia coli.

It was found that the nonspecific effect of ionic strength of the external solution on the enzymatic activity of E. coli cells consists in rapid changes in the permeability of cell membranes interacting with the substrate. This effect depends on the initial substrate concentration, i.e., ionic strength of the external solution, and is maintained for some time as the substrate concentration decreases. Chloramphenicol, a protein synthesis inhibitor, and sodium azide, a respiration inhibitor (300 micrograms/ml and 200 microM, respectively) do not change the enzymatic activity of E. coli cells during the synthesis of L-aspartic and L-malic acids from fumaric acid. The kinetic equations of L-aspartate and L-malate synthesis are described by equations of zero and intermediate (between zero and first) order, respectively.

[Determination of 3,4-dioxyphenyl-L-alanine by spectrophotometric and chromatographic methods in enzymatic synthesis using microbial cells]. / Opredelenie 3,4-dioksifenil-L-alanina spektrofotometricheskim i khromatograficheskim metodami v fermentativnom sinteze s pomoshch'iu kletok mikroorganizmov.

A possibility of using the ninhydrin reaction for 3,4-dihydroxyphenyl-L-alanine (DOPA) determining during the synthesis from pyrocatechol and ammonium pyruvate was verified by using free and immobilized cells of Citrobacter freundii, st. 62. Spectrophotometric assay was performed at the adsorption maximum for the DOPA-ninhydrin complex at 390 nm. DOPA can be reliably quantified in the presence of all components at 20-fold and greater dilution of the reaction mixture. A high-sensitive quantitative assay of the reaction mixture was developed based on phase-reversed HPLC. A quantitative correlation was observed between spectrophotometric and chromatographic assays. The assays were employed to study in detail the initial period and equilibrium of DOPA synthesis and its characteristic features, which made it possible to construct a kinetic model of the process.

[Enzymatic synthesis of L-malic acid from fumaric acid using immobilized Escherichia coli cells]. / Enzimaticheskii sintez L-iablochnoi kisloty iz fumarovoi s pomoshch'iu immobilizovannykh kletok Escherichia coli.

Optimal conditions were chosen for cultivation of Escherichia coli 85 cells with a rather high fumarate-hydratase activity on a cheap medium containing no edible raw material. An active biocatalyst for the synthesis of L-malic acid from fumaric acid was obtained based on E. coli 85 cells immobilized in carrageenan. The enzymatic synthesis of L-malic acid from potassium fumarate was kinetically studied and optimized. Some thermodynamic parameters of fumaric acid hydration into malic acid were determined. A technique for assaying the reaction mixture was developed that involved high performance liquid chromatography.

[Kinetic study of 3,4-dihydroxyphenyl-L-alanine synthesis in Citrobacter freundii cells immobilized in carrageenan]. / Kineticheskoe izuchenie sinteza 3,4-dioksifenil-L-alanina kletkami Citrobacter freundii, immobilizovannymi v karraginan.

A kinetic study was carried out of the enzymatic synthesis of 3,4-dihydroxyphenyl-L-alanine (DOPA) by the Citrobacter freundii 62 cells, possessing tyrosine-phenol-lyase (TPL) activity, immobilized in carrageenan, and optimum conditions of the reaction were found. The dependence of the TPL activity and its stability on the conditions of the DOPA synthesis was investigated. The TPL activity was higher and more stable in the immobilized cells as compared to free ones.

[Aspartase activity and the stability of Escherichia coli cells immobilized in different carrageenan samples]. / Aspartaznaia aktivnost' i stabil'nost' kletok Escherichia coli, immobilizovannykh v razlichnye obraztsy karraginana.

The cells of Escherichia coli 85 immobilized in carrageenan from various sources were being studied for the aspartase activity and stability. These properties of the resultant preparations which display a relatively high and stable biocatalytic activity were shown to be almost independent of the raw material from which carrageenan was obtained and of the degree of its purification.

[Comparison of the aspartase activity and its stability in Escherichia coli cells immobilized on polyacrylamide gel and carrageenan]. / Sravnenie aspartaznoi aktivinosti i ee stabil'nosti u kletok Escherichia coli, immobilizovannykh v poliakrilamidnyi gel' i karraginan.

The conditions for immobilization of Escherichia coli cells (Soviet strain 85) on the natural polysaccharide carrier carrageenan (Soviet-made) were investigated and kinetic regularities of the aspartase reaction catalysed by immobilized in carrageenan cells of E. coli 85 were established. The conditions for retaining a high aspartase activity and stability of biocatalysts based on the E. coli 85 cells immobilized in PAAG and carrageenan were determined using full-loaded tanks for continuous synthesis of L-aspartic acid. The time-stable aspartase activity of the biocatalyst can be increased by treating the beads of the catalyst with bifunctional reagents (hexamethylenediamine, glutaraldehyde), the most active catalyst for the biotechnological synthesis of L-aspartic acid being obtained when carrageenan is used.

[Stability of the biocatalysts of L-aspartic acid synthesis based on immobilized Escherichia coli cells]. / Stabil'nost' biokatalizatorov sinteza L-asparaginovoi kisloty na osnove immobilizovannykh kletok Escherichia coli.

Experiments were carried out to investigate the process of a continuous enzymatic synthesis of L-aspartic acid from ammonium fumarate in uniform filling flow reactors. Escherichia coli (Soviet strain 85) cells immobilized in polyacrylamide gel granules reinforced by a solid carrier were used as biocatalysts. The conditions, under which a high aspartase activity of the biocatalyst and a stable hydrodynamic performance of the reactor were maintained, were determined. The main kinetic characteristics of a continuous performance of the reactor for 150 days were obtained.

[Kinetics mechanism of L-aspartate synthesis from ammonium fumarate catalyzed by free and immobilized cells of E. coli]. / Kineticheskii mekhanizm reaktsii sinteza L-asparaginovoi kisloty iz fumarata ammoniia, kataliziruemoi svobodnymi i immobilizovannymi kletkami Escherichia coli.

A detailed study of kinetic peculiarities of the L-aspartate-ammonium-lyase reaction catalyzed by free and immobilized E. coli 85 cells incorporated into polyacrylamide gel, has been carried out. The effects of different types of bacterial cell "activation", substrate concentration and temperature on the reaction rate have been investigated. It was shown that the rate of the reaction is limited by the rate of the substrate transfer through the cell and cytoplasmic membranes and at sufficiently high values of the substrate can be described in terms of zero-order kinetics with respect to substrate and reaction products concentrations A kinetic model based on the diffuse and transfer processes of translocation of the aspartate-ammonium-lyase reaction participants through the cell and cytoplasmic membranes is proposed.

[L-asparatic acid synthesis from ammonium fumarate by free and immobilized Escherichia coli cells]. / Sintez L-asparaginovoi kisloty fumarata ammoniia svobodnymi i immobilizirovannymi kletkami Escherichia coli.

E. coli 85 cells with a high aspartate-ammonia-lyase activity were immobilized through polyacrylamide gel incorporation. Proper conditions to assay aspartase activity of E. coli cells were developed. Kinetic patterns of aspartate-ammonia-lyase reaction catalyzed by free and immobilized E. coli 85 cells were studied. The synthesis of L-aspartic acid from ammonium fumarate had the following characteristics: specific activity of (4--6) . 10(-5) mmole/mg.sec for free cells and (6--8) . 10(-5) mmole/mg.sec for immobilized cells with their content in polyacrylamide gel of 5--10 mg protein per g wet gelm pH 8.3--10.0.

[Dependence of the rate of aspartate ammonia-lyase reaction catalyzed by free and immobilized cells of E. coli on temperature and preliminary thermal treatment]. / Zavisimost' skorosti aspartat-ammiak-lia3noi reaktsii, katali3iruemoi svobdnymi i immobilizovannymi kletkami Escherichia coli ot temperatury i predvaritel'noi teplovoi obrabotki kletok.

The effects of temperature (45--55 degrees) and duration of thermal treatment on the L-aspartase activity of free and immobilized on polyacrylamide gel cells of E. coli, strain 85 were studied. It was found that preliminary thermal treatment of the cells at 50 degrees for 40--60 min is optimal for a high aspartase activity. Within the temperature interval of 20--55 degrees the temperature dependence of effective rate constants of L-aspartate synthesis obeys the Arrhenius equation, whereas the effective energy of activation is decreased from 12,6 to 3,6 kcal/mole, when the "activation" of the cells shows an increase.