[Molecular genetic determinants of intraspecific polymorphism of the phytopathogenic fungus Cryphonectria parasitica].

The review summarizes the current evidence on the phytopathogenic fungus Cryphonectria parasitica, which is a classic object for studying hypovirulence. Phenotypic manifestations of hypovirulence and themolecular mechanisms of action of the mycovirus Cryphonectria hypovirus (CHV) infecting the fungus are described in detail. Genetic determinants of vegetative incompatibility in C. parasitica (a phenomenon increasing polymorphism of the fungus and preventing CHV expansion) are considered. The data on C. parasitica polymorphism are correlated with the data on the distribution of different CHV species in the European, American, and Asian populations of the fungus.

Stress-induced changes in accumulation of sorbitol and in activities of concomitant enzymes in digestive gland of freshwater snail.

Sorbitol content was determined in the digestive gland of freshwater snail (Viviparus viviparus L.) in different seasons and in a short-term experiment on the water temperature decrease and on intoxication with cadmium chloride. In the model experiments, changes in activities of enzymes involved in sorbitol metabolism (acid phosphatases, sorbitol dehydrogenase, and aldose reductase) were also studied. Sorbitol was accumulated by the snail in response to the temperature decrease (as a cryoprotectant) and under conditions of acute intoxication (as a probable metabolic regulator or a nonspecific protective factor). However, the mechanisms of this accumulation are different: on cold adaptation sorbitol is produced as a result of reduction of glucose under the influence of aldose reductase, and on intoxication sorbitol is mainly produced from fructose under the influence of sorbitol dehydrogenase. Pathways of the sorbitol accumulation and its re-involvement into metabolism are not always the same, and this might be a mechanism for regulation of carbohydrate metabolism (at the initial stage of glycolysis) on adaptation to unfavorable factors of the environment.

Separation and characterization of deoxyribonucleases from hepatopancreas of freshwater snail in normality and under in vivo model intoxication.

Deoxyribonucleases (DNases) differing in the subcellular localization and specificity towards native and denatured substrates and in products of cleavage of endogenous DNA were isolated for the first time from the hepatopancreas of freshwater snail by differential sedimentation and preparative isoelectrofocusing. It was defined found that treatment with phenol leads to activation of most of the investigated DNases, especially in lysosomes, and induces two new DNases of lysosomal origin. The possible different participation of certain DNases of the snail hepatopancreas in the regulation of DNA degradation under intoxication is discussed.

[Effect of industrial toxic pollutants on the activity and isoforms of acid DNase in the freshwater snail (Viviparus viviparus L.)]. / Vliianie toksichnykh soedinenii tekhnogennogo proiskhozhdeniia na aktivnost' i mnozhestvennye formy kisloi DNKazy zhivorodki rechnoi (Viviparus viviparus L.).

The effect of various toxic compounds (phenol, gasoline, detergents, halogenated benzenes, and copper salts) on the activity and multiple forms of acid DNase was investigated in the liver of the widespread freshwater snail species Viviparus viviparus L. Characteristic variations in the specific activity and isoform pattern of the enzyme depending on pollutant concentration and exposure time were revealed. It was shown that the pattern of DNase isoforms in V. viviparus could be an index of water pollution.

Acid phosphatase complex from the freshwater snail Viviparus viviparus L. under standard conditions and intoxication by cadmium ions.

Acid phosphatases differing in both subcellular localization and substrate specificity were isolated for the first time from the liver of the freshwater snail Viviparus viviparus L. by preparative isoelectrofocusing. One of five characterized phosphatases is highly specific to ADP and the others can hydrolyze (at variable rate) a series of natural substrates. A scheme is proposed for the involvement of the studied phosphatases in carbohydrate metabolism. We have also studied some peculiarities of the effect of Cd2+ in vitro and in vivo on the activities of individual components of the acid phosphatase complex and corresponding changes in metabolism of the freshwater snail as a new test-object allowing the estimation of toxicity in water.

Isolation, purification, and characterization of a neutral Mg(2+)-dependent deoxyribonuclease of the Colorado potato beetle Leptinotarsa decemlineata Say.

A neutral Mg(2+)-dependent deoxyribonuclease from the Colorado potato beetle was isolated and characterized in physicochemical terms. An electrophoretically homogeneous preparation of the enzyme was obtained using salt fractionation, Sephadex G-100 gel filtration, and subsequent preparative isoelectrofocusing in an Ultrodex layer. The molecular weight of the purified DNase preparation (with a purification degree of 104) and its isoelectric point were 100 kD and 9.1, respectively. The enzyme activity was maximal at pH 7.2 and 46 degrees C in the presence of 10 mM Mg2+. The DNase of the Colorado beetle preferentially hydrolysed denatured DNA via the endonuclease pathway, degrading the substrate to oligonucleoside-3'-phosphates. As far as the physical and chemical properties are concerned, this Colorado beetle DNase seems different from previously investigated DNases of other insect species.

[Separation and properties of multiple forms of acid phosphatase from the tissues and organs of the mulberry silkworm]. / Razdelenie i svoistva mnozhestvennykh form kisloi fosfatazy tkanei i organov tutovogo shelkopriada.

The multiple forms of acid phosphatase from the hemolymph, fat body, intestinal wall and silk gland of the silkworm larvae differing in their mobility during polyacrylamide gel electrophoresis were separated by isoelectrofocusing, gel filtration and ion-exchange chromatography and characterized in terms of their molecular weight, isoelectric points and substrate specificity. It was found that silkworm tissues contain several enzyme forms possessing broad substrate specificity (EC 3.1.3.2) as well as forms predominantly catalyzing the hydrolysis of glucose-1-phosphate (EC 3.1.3.10). The enzyme forms with a broad substrate specificity were detected in all tissues studied with the exception of hemolymph and were found to have the molecular weights above 60,000, pI greater than pH 6.0 and the highest activity within the pH range of 3.0-4.5. The enzyme forms causing predominant hydrolysis of glucose-1-phosphate detected in the hemolymph, fat body and intestinal wall are characterized by Mr = 30,000-100,000, pI below 6.0 and the highest activity within the pH range of 4.8-5.6. A possible role of the multiple forms of acid phosphatase in silkworm metabolism is discussed.

[Isolation, purification and properties of acid deoxyribonuclease from silkworm Bombyx mori eggs]. / Vydelenie, ochistka i svoistva kisloi dezoksiribonuckleazy greny tutovogo shelkopriada Bombyx mori.

The acid deoxyribonuclease was isolated from Bombyx mori eggs and its physico-chemical properties were investigated. The enzyme purified 160-fold did not contain admixtures of phosphomono- and phosphodiesterases or ribonuclease. The molecular weight of the enzyme is 40 000 +/- 1000, isoelectric point lies at 6.5. The maximum activity is revealed at pH 5.2, 50 degrees. The DNAase is insignificantly activated by Mg2+ and is inhibited by Cu2+ and Zn2+. The enzyme preferentially hydrolyzes native DNA and is an endonuclease splitting DNA down to 5'-oligonucleotides.

[Isolation, purification and properties of acid ribonuclease from the lysosomal fraction of silkworm eggs]. / Vydelenie, ochistka i svoistva kisloi ribonuckleazy lizosomal'noi fraktsii greny tutovogo shelkopriada.

Acid ribonuclease (ribonucleate-3'-oligonucleotide hydrolase, EC 3.1.4.23) has been isolated from the lysosomal fraction of Bombyx mori eggs. The enzyme has a pH optimum of 4,7 and a molecular weight of 17 000 +/- 1000; the isoelectric point of the enzyme lies around 6,0. The enzyme splits RNA and poly(U) down to nucleoside-3'-phosphates to form intermediates--nucleoside-2',3'-cyclophosphates. Polyadenylic acid is hydrolyzed in the presence of the enzyme down to oligonucleotides. Mg2+ suppress the enzyme activity.