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N F Avrova

Publications and source records attributed to N F Avrova.

At least 55 records · Page 3Linked to original sources
PubMedDate not supplied

[Brain lipid biochemistry of the sturgeons Acipenseridae].

Brain lipids of 4 species of sturgeons-Acipenser güldenstädti, A. stellatus, A. ruthenus and Huso huso-have been investigated. In whole brain homogenates the content of the basic phospholipid families, their fatty acid composition as well as the content of glycosphingolipids-gangliosides, cerebrosides and sulfatides were studied. The quantitative relations between different molecular ganglioside fractions and their fatty acid composition, as well as the relative content of hydroxycerebrosides and cerebrosides with normal fatty acids were determined. The brain lipids of Acipenseridae were compared to previously obtained data on the brain of Elasmobranch and Teleost fishes. The brain lipid pattern of the four sturgeon species is very similar, but it differs greatly from that of Elasmobranch and of Teleostean brain, being in some respect more like the type of bony fish brain, in others the kind of brain of sharks and rays, and frequently considerably differing from both these types. The conspicous peculiarity in the content and molecular characteristics of the brain lipids of Acipenseridae compels us to agree with the opinion expressed by the late A.N. Belozerski and his coworkers [26, 27], based on a detailed study of fish DNA nucleotides, that the Ganoid fish are to be regarded as an independent class.

Animals↗
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[Concentration and composition of cerebral gangliosides in Down's disease].

Content and composition of gangliosides were studied in brain white and grey substances of patients with mongolism. Content of gangliosides, which are typical components of plasmatic membranes of nervous cells, was decreased in brain grey substance of the patients as compared with control group, whereas content of the lipids was increased in white substance. Differentiation of neurones appears to be inhibited in mongolism. Content of disialoganglioside GDIa exceeded the content of other gangliosides in brain white and grey substances in normal state; content of GMI, GTI, GDIb was also increased. Composition of gangliosides from brain of the patients with not distinctly altered as compared with that of children of control group.

Age Factors↗
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[Morphological differentiation and change in the lipid composition of neuroblastoma C1300 cells treated with gangliosides].

The effect of exogenous gangliosides on the morphological differentiation of neuroblastoma 1300 N18 cells was studied Simultaneously the content of gangliosides and lipid composition of the cells was investigated. Gangliosides were shown to increase the quantity of cells with long neurites. This effect depended on the dose of gangliosides. The addition of 50 and 100 micrograms of gangliosides per 4 ml of serum-free culture medium increased the quantity of cells with neurites by 38 and 63.4%, respectively. The level of morphological differentiation in cells cultivated with gangliosides was higher than in cells incubated with 5'-bromodeoxyuridine. Noticeable quantities of lysophosphatidylcholine (absent in the control) appeared in ganglioside-treated cells and the level of cholesterol increased. The amount of other lipid compounds in cells differentiated in the presence of gangliosides was similar, but not identical to the quantity of lipid compounds in cells differentiated by 5'-bromodeoxyuridine and by the serum-free medium.

Animals↗
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[Concentration and composition of gangliosides in portions of the vertebrate brain].

Studies have been made on gangliosides from various parts of the brain in 5 species of cartilaginous fishes, 2 species of teleosts, 2 amphibian species, 2 avian species and 3 species of mammals. Almost in all the species investigated, the highest content of gangliosides per weight unit of the brain were found in the forebrain (determinations were carried out by sialic acid, sometimes by sphingosine). Ganglioside content of brain structure in warm-blooded animals is higher that in corresponding structures of fishes and amphibia. Comparative studies on ganglioside composition in the brain of fishes and mammals indicate that brain structures exhibit the same pattern of molecular organization, as the whole brain of the species studied (high polysialoganglioside content in teleosts, predominance of gangliosides with a short carbon chain in cartilaginous fishes, etc.). Besides this fact, peculiarities of composition typical of the brain structures were found as well (more polar composition of gangliosides of the cerebellum and some other ones).

Animals↗
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[Localization and functional role of gangliosides from nerve tissue of vertebrates].

Gangliosides in the animal organism are typical components of plasma membranes of nerve cells in which the concentration of polysialogangliosides is especially high. The high concentration of tri- and tetrasialoganyliosides and ganglioside GD1b is peculiar to primary cultures of nerve cells, whereas these gangliosides are practically not present in the culture of the transformed nerve cells which have lost their ability to sinaptogenesis, they are not found in cultures of oligodendro- and astroglia as well. The addition of exogenic gangliosides to nerve cells cultures stimulates the formation of processes in these cells and promotes their survivability. The neuritogenic and neuronotrophic effect of gangliosides, their participation in the processes of neurons' regeneration are shown in the in vivo experiments. Gangliosides are carriers of antigenic determinants typical of the cellular surface of neurons (or other cells) as well as of cells of different malignant tumours; typical carcinoembryonal antigenes are revealed among them. Such functions of gangliosides as participation in the processes of intercellular interaction, adhesion, pneuritogenic effect, possible participation to memorize one or another habit are, probably, interrelated and mutually conditioned. Recently the data, being in controversy with the notion that gangliosides are components of receptors of hormones and mediators, are obtained. Evidently, it ought to speak about the modulation of cell response by them on the action of these effectors.

Animals↗
PubMedDate not supplied

[Brain lipids of a mammoth, Elephas primigenius, which died more than 40,000 years ago].

Studies have been made on the brain lipids of the 6--7-month mammoth which remained in the eternal ice for more than 40.000 years. Thin layer chromatography of chloroformmethanol extract of the brain lipids shows that all glycerophospholipids in the brain were destroyed. On the contrary, sphingophospholipid sphingomyelin yielded the evident spot which was identified by specific reactions and by comparison with sphingomyelin from the brain of rat. Sphingomyelin content was evaluated. Using gas-liquid chromatography, fatty acid composition of sphingomyelin was investigated. It was found to be close to that in contemporary mammals. Other shingolipids -- cerebrosides, sulfatides, gangliosides -- persisted (probably, only partially) and were studied quantitatively. Relative content of cerebrosides with normal fatty acids and hydrooxyacids was determined. Studies were also made on fatty acid composition of cerebrosides, sulfatides and gangliosides, as well as on the composition of spingosine bases of gangliosides. Free cholesterol was found in the brain of the mammoth. Other sterols were not detected. With respect to quantitative evaluation of the preserved lipids, it should be mentioned that on the one hand, the brain underwent dehydration which increased lipid content per a unit of "wet" weight, whereas on the other one lipids were partially degraded, this process decreasing their content.

Animals↗
PubMedDate not supplied

[Composition and structure of the chief gangliosides in the brain of the lamprey Lampetra fluviatilis].

It has been shown that 4-sphingenine is the main sphingoid in lamprey brain gangliosides. Saturated and monoenoic fatty acids were found to predominate, the main fatty acids in the lamprey brain are presented by stearic (43-49% of total fatty acids) and oleic ones. N-acetylneuraminic acid is the only sialic acid found in gangliosides from the lamprey brain. Other components of ganglioside molecules are glucose, galactose and N-acetylgalactosamine. Two main lamprey brain gangliosides which constitute more than 90% of lipid-bound sialic acid, were found to be trisialogangliosides. It was shown that both gangliosides have the following structure in their molecules: (formula see text). They differ in the position of two other sialic acid residues. Data on lamprey brain gangliosides in the literature are practically absent. The data obtained in the present study confirmed the conclusions on changes in the hydrophobic part of ganglioside molecule in evolution of vertebrates and made it possible to define more exactly the molecular evolution of ganglioside carbohydrate component.

Animals↗
PubMedDate not supplied

[Role of gangliosides in the processes of calcium ion transport across the membranes of nerve cells].

It has been demonstrated that the content of extracellular Ca in the nervous system is inversely related to the content of gangliosides. The results obtained on invertebrates, lower and higher vertebrates indicate that the highest content of extracellular Ca is typical of the nervous tissue of invertebrates, whereas the lower one--of the nervous tissue of higher vertebrates (mammals). Ganglioside content, on the contrary, is the highest in the brain tissue of the higher vertebrates (mammals and birds), being significantly lower in lower vertebrates; no gangliosides was found at all in the nervous tissue of protostomian invertebrates. The highest ganglioside content in the organism of vertebrates is characteristic to the surface membranes of the nervous cells, especially in the region of synapses. Functional significance of the inverse relationship between the content of extracellular Ca and gangliosides is discussed from the standpoint of one of the authors (R. Veh) who postulated the existence of calcium--ganglioside buffer in the vicinity of the surface of the nervous cells.

Amphibians↗