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Biomedical subjects

V N Popov

Publications and source records attributed to V N Popov.

36 records · Page 2Linked to original sources
PubMed1996

[Purification and properties of isocitrate lyase and malate synthase from fasting rat liver].

Key enzymes of glyoxylate cycle, isocitrate lyase and malate synthase, are active in the fasting rat liver. The enzymes were synthesized on day 3 after food deprivation and their activities were maximal on day 5 of fasting. Specific activity of isocitrate lyase was 0.06 units/mg protein and specific activity of malate synthase was 0.03 units/mg protein. Isocitrate lyase was isolated and purified by ammonium sulfate fractionation, DEAE-cellulose chromatography and Toyopearl HW-65 gel filtration. Enzyme was purified to specific activity of 9.0 units/mg protein with 8.2% yield. Molecular mass of isocitrate lyase was 145 kD according to gel filtration. Catalytic characteristics of isocitrate lyase indicate that the enzyme follows Michaelis-Menten kinetics (Km for isocitrate is 0.07 mM), is competitively inhibited by glucose-I-phosphate (Ki = 1.1 mM) and glucose-6-phosphate (Ki = 1.9 mM), and is activate by ADP; optimal pH is 7.4. Malate synthase was partially purified by ammonium sulfate fractionation and Sephadex G-25 gel filtration. Enzyme was purified to specific activity of 0.15 units/mg protein with 45% yield. Km of malate synthase for acetyl-CoA was 0.2 mM and Km for glyoxylate was 0.3 mM; optimal pH was 7.6.

Animals↗
PubMed1995

Alternative system of succinate oxidation in glyoxysomes of higher plants.

Succinate oxidation in scutella of germinating seeds of wheat and maize was investigated. Besides oxidation via succinate dehydrogenase (SDH; EC 1.3.99.1), an alternative path of succinate oxidation insensitive to SDH inhibitors--malonate and thenoyltrifluoroacetone (TTFA)--was revealed. Using isopicnic sucrose gradient it was shown that this path is localized in glyoxysomal membranes. Glyoxysomal succinate oxidase (GSO) converts succinate directly into malate with the production of hydrogen peroxide identified using auxiliary enzymes malate dehydrogenase and peroxidase. GSO is most active during the intensive operation of the glyoxylate cycle (3-5 days of germination). Quinacrine, the inhibitor of flavine-containing oxidases, strongly suppressed the activity of GSO. Km for succinate is 18 mM for GSO from maize scutellum. It is concluded that in scutella of cereal seeds the glyoxysomal succinate oxidation non-linked with ATP synthesis operates.

Hydrogen-Ion Concentration↗
PubMedDate not supplied

[Induction of glyoxylate cycle enzymes in various tissues from starving rats].

The induction of glyoxylate cycle enzyme activities was revealed in the liver and other organs of starving rats. A five day deprivation of food was followed by the appearance of isocitrate lyase (ICL) and malate synthase activities and the increase of malate dehydrogenase (MDH) and citrate synthase activities. The induction of MDH was associated with the appearance of its new isoform with Rf 0.52. ICL activity was revealed in the liver, blood, pancreas, kidney, lungs, heart, and skeletal muscles of starving rats, reaching a peak on day 5 of food deprivation. No significant changes of blood glucose level in starving rats were revealed until day 9. A homogeneous ICL preparation with a specific activity of 12.4 IU per mg protein was obtained as the results of five-stage purification procedure.

Aconitate Hydratase↗
PubMedDate not supplied

[Genotype peculiarities of crossability of cultivated sunflower with wild species and the use of embryo culture in interspecific hybridization].

Peculiarities of the genotype effect of cultivated and wild sunflower species on crossability indices and in vitro hybrid embryonic development have been investigated. It was shown that selection of initial material can considerably influence seed-setting and in vitro embryonic development in the cross group of cultivated sunflower with annual and perennial wild species. The range of plant hybrids obtained through somatic embryogenesis and induction of adventitious shoots was higher in comparison with direct growth of embryos in in vitro culture.

Crosses, Genetic↗
PubMedDate not supplied

[Polymorphism and genetic control of some isozyme systems in mutant sunflower lines].

Polymorphism of six isozyme systems (ME, EST, 6-PGD, AAT, ACP, IDH) of sunflower mutant inbred lines has been studied. It was shown that only three of them were polymorphic (ME, EST, 6-PGD). Two isoforms were observed for each polymorphic enzymic zone. Genetic control of malic-enzyme has been studied and it was determined that the identified polymorphic zone of the enzyme was controlled by one gene. The genes of malic-enzyme synthesis, anodal esterase and 6-phosphogluconat-dehydrogenase are inherited independently.

Electrophoresis, Polyacrylamide Gel↗
PubMedDate not supplied

[Anisakiasis in the Caspian seal].

On the basis of 548 helminthological dissections the main foci of Anisakis infection of Caspian seal and the character of pathomorphological process in the stomach infected with the nematode Anisakis schupakovi have been established.

Animals↗
PubMedDate not supplied

[Radiation dose to patients and informativeness of the images obtained during eye examinations using x-ray computed tomography].

Reducing the scanning time and the X-ray tube anode current to 80-100 mA is the main way of reducing the radiation dose without noticeably lowering the tomogram image quality in examination of the eye area using the USA QUAD-1 X-ray computer tomograph of the fourth generation. The optimum tube voltage is 140 kW. Narrowing the collimator slit and reducing the number of sections can also lower the total radiation dose, but these measures are less universal for they are determined by clinical situation.

Eye↗
PubMedDate not supplied

[Helminth fauna of Bering Sea pinnipeds from Karaginskiy Bay].

The helminthological investigations were conducted from May 6 to May 28, 1972 in the Karaginsk Gulf of the Bering Sea. The helminths were collected from 124 specimens of Phoca vitulina largha, 9 specimens of Erignathus barbatus nauticus, 9 specimens of Pusa hispida krascheninnikovi and 9 specimens of Histriophoca fasciata. In all, 23 species, 2 immature and 1 larval form of helminths were recorded. The data are given on the localization of helminths, intensity and extensity of their invasion, pathogenic effect on the host. The age dynamics of the helminths from Phoca vitulina largha was studied. For the first time are reported the trematode Orthosplanchnus pygmaeus, the cestode Diplogonoporus tetrapterus and nematodes Aniskis simplex, Anisakis sp. and Parafilaroides krascheninnikovi in Phoca vitulina largha and the nematodes Anisakis sp. and Phocascaris cystophorae in Pusa hispida krascheninnikovi.

Age Factors↗