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S A Shukoliukov

Publications and source records attributed to S A Shukoliukov.

At least 19 recordsLinked to original sources
PubMed2004

[Visual cycle and dark adaptation: a new approach in research].

Visual cycle is the series of reactions that support regeneration of the visual pigmen after its photolysis in retinal rods and cones. Inherited or acquired deficiencies of the visual cycle impair dark adaptation and lead to a series of visual disorders. The paper describes a new approach to study of the visual cycle that uses fast dichroic microspectrophotometer. The method allows studying interconversion of bleaching products in single intact photoreceptors in condition approaching the situation in vivo. Using this approach, we established a complete scheme of transitions between metarhodopsins, retinal and retinol in amphibian rods. It appeared that the decay of metarhodopsins controls both the time course of rod dark adaptation following small bleaches and the production of retinol that is the substrate for rhodopsin regeneration. We also obtained novel data on kinetics of the decay of cone metapigments that was found to be by an order of magnitude faster than in rods. Possible application of the method for further study of the visual cycle in normal and pathological conditions is discussed.

Amphibians↗
PubMed1985

[Interrelationship of the antibiotic and proteolytic activities of the producer Streptomyces antibioticus when different substances are added to the culture broth].

Interrelation between biosynthesis of oleandomycin and alkaline proteases was studied during cultivation of Str. antibioticus in flasks with the complex soybean-corn medium containing lactose. Increasing of the activity of oleandomycin and that of alkaline proteases in the fermentation broth was simultaneous and reached the maximum within 168-192 hours. After that period the activity levels lowered. ATP and glucose induced inhibition of the antibiotic activity and stimulation of the proteolytic activity, 1.25- or 1.5-fold dilution of the fermentation process resulted in stimulation of both the antibiotic activity and the proteolytic activity. At the same time organic acid salts, leucine or gelatin induced their inhibition. Interrelation between these processes was rather complex since lowering of the levels of autolytic processes in the cells by inhibition of the proteases with physiological regulators and respective prolongation of the culture productive phase did not result in increase of the antibiotic yield.

Culture Media↗
PubMed1984

[Oleandomycin content of mycelium and fermentation solution during cultivation of Streptomyces antibioticus].

The time-course of the oleandomycin content in the mycelium and fermentation broth-filtrate was studied by the microbiological assay at different periods of cultivation of strains 471 and 961 in fermenters and flasks containing a rich soybean-corn medium. It was shown that centrifugation of the mycelium over the sucrose density gradient induced a 25-80 per cent decrease in its moist weight at the expense of removal of the admixture components of the rich medium. Addition of glucose (2 per cent) to the culture-grown in a lactose medium by the 72nd hour of fermentation had no effect on further increase of the cell biomass. However, it lowered the content of the mycelium-fixed and excreted antibiotic at all the subsequent fermentation periods. The content of oleandomycin in the untreated mycelium was only 0.36 per cent of its content in the fermentation broth filtrate. After centrifugation of the mycelium over the sucrose density gradient and its intensive washing with distilled water the content of the mycelium-fixed antibiotic decreased still more. The time-course of the content of the mycelium-fixed and excreted oleandomycin was characterized by the presence of two activity peaks; by the 80-110th and by the 140-170th hour of cultivation.

Culture Media↗
PubMed1979

[Electrophoretic study of products of wall-eyed pollock and bovine rhodopsins fragmented by papain].

Fragmentation of wall-eyed pollock and bovine rhodopsins by papain in the photoreceptor membrane was studied by sodium dodecyl sulfate electrophoresis. A scheme of step-wise rhodopsin proteolysis is presented. The molecular weights and localization of the carbohydrate and chromophore components of the fragments formed were determined. The data obtained suggest that the photoreceptor membranes of both rhodopsins contain three sites accessible to water environment and are indicative of topographical similarity of the rhodopsins.

Animals↗
PubMed1978

[Accessibility of sulfhydryl groups to 5,5'-dithiobis-2-nitrobenzoic acid and acid-base properties of bovine and walleye pollock rhodopsin preparations].

Both the number of exposed SH-groups and the rate of reaction with 5,5'dithiobis-2-nitrobenzoic acid (DTNB) in walleye pollock and bovine rhodopsin depend on a degree of native structure of the preparation to be investigated. The preparations studied can be arranged in the order of increase of these parameters as follows: ROS less than rhodopsin extracted by digitonin less than triton X-100 less than cetyltrimethylammonium bromide (CTAB) less than sodium dodecylsulphate (SDS). After illumination of ROS and digitonin, triton X-100 and CTAB-solubilized rhodopsin, and increase was observed in the number of modified SH-groups. Dark and bleached samples of walleye pollock rhodopsin exhibited a faster rate reaction and a more number of modified SH-groups as compared to bovine preparation. The differences between bovine and walleye pollock preparation disappeared after complete opsin unfolding as a result ROS solubilization in SDS. Six SH-groups per molecule of rhodopsin were modified in both preparation under these conditions. No differences in the number of cysteine residues (10--11), disulfide groups (2), acid (35--40) and base (25--30) titratable groups per rhodopsin molecule were found between bovine and walleye pollock ROS membranes. The isoelectric point of both rhodopsin preparations was within the pH range 5.2--5.6. After proteolysis of ROS with papain, a fragment with molecular weight 24500 +/- 1000 was detected, which contained the same number of SH-groups and cysteine residues as in the case of intact rhodopsin. The results obtained suggest that, in spite of a similar primary structure, the walleye pollock visual pigment has more "loose" and "fluid" space packing in the ROS membrane than the bovine pigment.

Animals↗
PubMed1978

[Modification of retinal photoreceptor membranes and Ca ion binding].

Calcium binding by modified photoreceptor membranes of cattle retina has been studied. Ca2+-binding the membranes significantly changes after C-phospholipase treatment, displaying the initial growth (less than 65% of lipid phosphorus removed) with subsequent decrease (more than 65% of phosphorus removed). Liposomes of the photoreceptor membranes lipids were found to bind more calcium than do the native photoreceptor membranes. Proteolytic enzymes (papaine, pronase) splitting some rhodopsin fragments do not affect the ability of the membrane to bind Ca2+. The increase of light-induced Ca-binding is observed only after the outer segments preincubation under conditions providing for rhodopsin phosphorylation. This effect was observed also after the splitting of the rhodopsin fragment by papaine. It is concluded that calcium binding in the photoreceptor membranes is mainly due to the phosphate groups of phospholipids.

Animals↗
PubMed1978

[Some features of rhodopsin regeneration process in the presence of exogenous 11Z-retinal in teleosts].

The rate of rhodopsin regeneration in decolorized rod outer segments ROS of pollock and ruff in the presence of exogenous 11Z-retinal is found to depend slightly on the temperature. The Arrhenius curve is linear within 0--20 degrees C and 0--30 degrees C in case of pollock and black ruff ROS respectively. The increase of the regeneration temperature above the upper limit results in both cases in the decrease of the chromophore binding rate due to the temperature denaturation of fish opsin. The rate of opsin regeneration in bovine ROS is temperature-dependent within 0--50 degrees C, the Arrhenius curves having a specific break with the temperature conversion at 12--13 degrees, which indicates a different 11Z-retinal binding rate with bovine opsin at low and high temperatures. Maximal rhodopsin regeneration temperature was observed within 5--10 min. for fish ROS and 1.5 hour for bovine ROS. Trimethylcyclohexene derivatives with a side chain of about 7 carbon atoms and 13Z-retinal competitively inhibited the rhodopsin regeneration in pollock and bovine ROS, while 13E-11, 12-dehydroretinal and all-E-retinal did not effect this process. Some peculiarities of the rhodopsin regeneration process in fish are discussed in connection with the molecular organization of a lipid phase of photoreceptor membrane and chromophore-binding region.

Animals↗
PubMed1977

[Regeneration of rhodopsin in marine teleost fishes in the presence of exogenic of 11-cis-and all trans-retinals].

Regeneration of rhodopsin of the sea perch (Sebastodes schlegeli) and walleye pollock (Theragra chalcogramma) was studied in different preparations of eye after the addition of 11-cis- and all trans-retinals and at the expense of endogenic sources. It was established that the regeneration of rhodopsin in the eye cup, homogenate of retina and rod outer segments (ROS) at the expense of endogenic sources was extremely low and it was slightly forced by the addition of the pigment epithelium to the last two preparations. The binding degree of 11-cis retinal of walleye pollock ROS decreased with the increase of temperature of the incubation mixture and the increase of duration of storage of ROS at the temperature--10 degrees. Partial removing of lipids by hexane decreased the percentage of regeneration of the ROS preparation; on the other hand, the peroxidation of lipids practically did not affect the regenerative ability of fresh-obtained preparations. After solubilization of opsin by digitonin and sodium cholate, 40- and 50%-decreases of binding of 11-cis retinal were observed respectively. The digestion of ROS by papain, which caused no changes in the spectral properties of dark preparations, completely eliminated the regenerative ability of ROS. Regeneration of ROS at the presence of all trans-retinal proceeded at a very low speed. The specificity of the process of regeneration of rhodopsin in fishes is discussed.

Animals↗
PubMed1976

[Electrophoresis and electrofocusing of rhodopsin solubilized by triton X-100].

Detergent-rhodopsin micells (component I) were separated from other fast and slow migrating protein components under electrophoresis of triton X-100 solubilized bovine rod outer segments (ROS). Treatment of ROS by alum caused a complete disappearance of non-rhodopsin proteins and the appearance of slow migrating band (component II). Preliminary bleaching of dark extracts did not affect the migration rate of the component I. The addition of urea to solubilizing mixture caused the increase of component I content and the diffusity components I and II bands. The rate of electrophoretic migration and the content of components I and II sharply decreased together with the appearance of fast migrating pink-brown band after the addition of 2-mercaptoethanol. The extracts from alum-treated ROS were separated into 15-20 protein bands under acrylamide gel isoelectric focusing. Such protein heterogeneity probably depended on the ability of triton X-100 to form micells with different isoelectric points during the interaction with ampholines in the electric field. These micells, having different isoelectric points, are shown to contain one and the same protein--opsin.

Animals↗
PubMedDate not supplied

[Lactate dehydrogenase isoenzymes in the eye, cardiac and skeletal muscles of several decapods].

Properties of lactate dehydrogenase (LDH) in the eye, heart and muscles of Hemigrapsus sanguineus, Paralithodes camtschatica, Erimacrus isenbeckii, Pandalus latirastrus, Pagurus brachiomastus have been studied with acrylamide gel electrophoresis and kinetics analysis. LDH in all the tissues of all the representatives studied was found to be specific for L-pyruvate and lactate; it migrated in electrophoresis as a single band revealing low mobility towards anode. The isoenzyme from P. camtschatica and P. latirastrus differed from the isoenzymes of other animals studied by higher mobility towards anode that reflected higher negative value of its total charge. The LDH isoenzymes in all the animals studied resembled the A4 (LDH5) of the vertebrates being unstable to the denaturing action of high temperature and being unaffected by high concentrations of pyruvate up to 1.0.10-3M. On the other hand, in conrast to the A4 of mammals, the LDH in question displayed enhancement of the reaction rate and decrease of the Km values upon increase in the NAD+ and NAD.H concentrations both in the presence of high or low lactate and pyruvate concentrations. The isoenzymes displayed catalytic activity also in the presence of NADP, the Km values for pyruvate in the presence of equimolar (2.25 mM) concentrations of NAD.H or NADP.H were practically identical and were found to be within the limits of 14-26.10-5 M. Molecular weight of the LDH studied assessed by the gel filtration method was found to be 130-140,000. It is suggested that the LDH isoenzyme from the representatives of the decapod crayfish studied is homologous in its certain properties to the homotetrameric A4 form of the vertebrates.

Animals↗