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Biomedical subjects

N Ueta

Publications and source records attributed to N Ueta.

At least 55 records · Page 3Linked to original sources
PubMed1980

Low density lipoproteins from human ascites plasma. Characterization and degradation by sodium deoxycholate.

The low density lipoproteins (LDL) in human ascites plasma were separated into two sublcasses by ultracentrifugation. The chemical compositions of the two LDLs were determined. On a weight percentage basis, LDL1 contained cholesterol ester, 20.8%; cholesterol, 19.3%; triacylglycerol, 19.7%; phospholipid, 22.1%; and protein, 10.8%. LDL2 contained cholesterol ester, 21.6%; cholesterol, 14.5%; triacylglycerol, 20.1%; phospholipid, 20.6%; and protein, 18.0%. The relative content of triacylglycerol and the ratio of unesterified cholesterol to esterified cholesterol in both LDLs were very high compared to corresponding human serum LDLs. Following the treatment of these LDLs with 575 mg of sodium deoxycholate per 10 mg of lipoprotein protein, a triacylglycerol-protein rich fraction was obtained by gel filtration in the presence of a micellar concentration of the detergent.

Amino Acids↗
PubMed1979

Effect of growth temperature on lipid and fatty acid compositions in the blue-green algae, Anabaena variabilis and Anacystis nidulans.

The lipid composition was affected by growth temperature in Anacystis nidulans, but was not in Anabaena variabilis. A. variabilis contained fatty acids of 18 and 16 carbon atoms, which were localized at 1- and 2-positions, respectively, of the glycerol moiety of lipids. Desaturation of C18 acids was affected by the growth temperature. A. nidulans contained fatty acids of 14, 16 and 18 carbon atoms. Monounsaturated and saturated acids were esterified mainly to 1- and 2-position, respectively. Desaturation and chain length of fatty acids were influenced by the growth temperature. The variations in lipid and fatty acid compositions with the growth temperature are discussed in relation to the growth temperature-dependent shift of thermotropic phase transition temperature of the membrane lipids in the blue-green algae.

Chlorophyll↗
PubMed1979

Water-soluble lipoproteins from yolk granules in sea urchin eggs. II. Chemical composition.

The chemical composition of yolk lipoproteins (YLP-1, 2, and 3) was determined. YLP-1, 2, and 3 were quite similar as regards the chemical composition of lipids, proteins, and carbohydrate moieties. Each lipoprotein has an average dry weight composition of lipids (55--72%) and apo-lipoproteins (28--45%) containing protein, hexose, hexosamine, and sialic acid. In each lipoprotein, triacylglycerol is a major lipid component (70--83%), followed by phospholipid (8--16%), cholesterol (free and esterified, 8--10%), and free fatty acid (3--4%). Phosphatidylcholine and phosphatidylserine account for 68--74% and 16--24% of the phospholipids, respectively. The fatty acid compositions of total lipids from each lipoprotein are quite similar, with a high degree of unsaturation (63--65%). The carbohydrate content of apolipoprotiens from each lipoprotein is remarkably high (27--31% of apo-lipoproteins) and their composition is very simple: mannose and glucosamine are major constituents in the polysaccharide moiety of each lipoprotein and sialic acid is all in the N-glycolyl form. The amino acid compositions of apo-lipoproteins are quite similar in YLP-1, 2, and 3, with high contents of aspartic acid, glutamic acid, threonine, serine, and leucine. Furthermore, a small amount of glycolipids is present in the yolk lipoproteins. They were separated into six components on TLC. All of them are resorcinol-positive, indicating the presence of sialoglycolipids.

Amino Acids↗
PubMed1978

omega- and (omega--1)-hydroxylation of fatty acids by frog liver microsomes. Substrate specificity and other properties.

Frog liver microsomes catalyzed the hydroxylation of various saturated fatty acids whose chain lengths were from 8 to 18 carbon atoms into the corresponding omega- and (omega--1)-hydroxy derivatives. In addition, small amounts of the dicarboxylic acids and (omega--1)-keto acids were also formed from all the fatty acids. The relative activity of the hydroxylase with the substrates was as follows: C13(100), C12(98), C14(88), C10(62), C16(34), C18(29), and C8(8). The percentage of omega-hydroxy derivative relative to the (omega--1)-isomer increased with increasing carbon chain length of the fatty acid substrate. Oleate, linoleate and linolenate were also tested and found to be at least as active their saturated analog (stearate). Both NADPH and O2 were required for hydroxylase activity. The apparent Km for NADPH was 3.7 . 10(-5) M, and NADH had very little effect. The apparent Km value for laurate was 1.5 . 10(-5) M. The hydroxylating system was about 50% inhibited by 10 mM KCN and 81% inhibited by CO at a CO : O2 ratio of 4.0. In contrast, NaN3 showed no effect on hydroxylation.

Animals↗
PubMed1978

Water-soluble lipoproteins from yolk granules in sea urchin eggs. I. Isolation and general properties.

Most of the water-soluble lipoproteins in sea urchin eggs (Hemicentrotus pulcherrimus) were localized within yolk granules. Under hypotonic conditions, yolk granules released lipoproteins and a 24S protein species as high molecular weight components; the lipoproteins constituted about 40% of the total materials released. Three yolk lipoproteins(YLP-1, 2, and 3, in order of quantity) were isolated by ultracentrifugation and gel filtration. The hydrated densities of YLP-1, 2, and 3 were 1.027, 1.062, and 1.009 g/cm(3), respectively. YLP-1, 2, and 3 contained glyceride as a major lipid in quantities of 3.1, 1.8, and 4.3 times the amount of each protein, respectively. These lipoproteins contained large amounts of carbohydrate. Sodium dodecyl sulfate polyacrylamide gel electrophoresis revealed four major periodic acid-Schiff (PAS) positive polypeptide bands common to the three lipoproteins. All the constituent polypeptides of the 24S protein were also PAS positive. Electron microscopy of negatively stained YLP-1, 2, and 3 revealed the average diameters to be 36, 29, and 48nm, respectively. The 24S protein appeared to be cylindrical in shape with average exterior dimensions of 10--20 nm. Thin-section micrographs showed that yolk granules are packed with particles around 30 nm in diameter, suggesting that these particles are not the 24S proteins but the lipoprotein particles.

Animals↗
PubMed1978

An analysis of the fatty acid composition of total lipids from mycoplasmas.

The fatty acid composition of the total lipids obtained from 9 species (22 strains) of Mycoplasma and 3 species (7 strains) of Acholeplasma was determined by gas-liquid chromatography (GLC). The major fatty acids of the Mycoplasma species were palmitic acid (C16:0), stearic acid (C18:0), oleic acid (C18:1), and linoleic acid (C18:2). Lauric acid (C12:0) and myristic acid (C14:0) were present in small amounts in this genus. For the Mycoplasma species, the most prevalent fatty acid was C16:0 or C14:0, and other leading fatty acids were C12:0, C18:0, C18:1 and C18:2. A substantial amount of C12:0 and C14:0 was found in the Acholeplasma species. It was confirmed that C12:0 and C14:0 were synthesized de novo, based on the fact that 14C-acetate was incorporated into these acids. The total percentage of C16 fatty acid was less than that of C18 fatty acids in all the strains of Mycoplasma and Acholeplasma except 4 strains. This may be related to osmo-regulation of the L-forms of Streptococci as mentioned in other reports.

Acholeplasma↗
PubMed1977

Isolation and partial characterization of the serum low density lipoprotein from bullfrog, Rana catesbeiana.

The chemical and physical properties of bullfrog serum low density lipoprotein (LDL) were investigated. On a weight percentage basis, LDL contained cholesterol ester, 30.3%; cholesterol, 5.6%; triglyceride, 12.5%; phospholipids, 23.3%; and protein, 22.4%. The fatty acid compositions of triglycerides and major phospholipids from the bullfrog serum LDL were quite similar to those of human serum LDL. However, the fatty acid composition of the chlesterol ester from the bullfrog serum LDL was quite different from that of the human serum LDL. The average particle weight, determined by gel filtration, was 2 X 10(6) daltons. This value is very close to that of human LDL. In the fluorescence emission spectrum of bullfrog serum LDL, the emission maximum was 324 nm. The amino acid composition of the apo-LDL resembled that of human apo-LDL.

Amino Acids↗
PubMed1977

The structure of triglyceride in human sebum.

1) A relatively large quantity of branched chain and odd-carbon-number fatty acids were found in human sebum. 2) These acids were present in each lipid fraction (cholesterol ester, triglyceride and free fatty acid) of sebum. 3) In the triglyceride molecule, these acids were found mainly on the 2-position.

Chemical Phenomena↗
PubMed1976

Chemical characterization of the serum very low density and high density lipoproteins from bullfrog, Rana catesbeiana.

The chemical properties of very low density and high density lipoproteins of adult bullfrog serum were determined. This serum contained extremely low levels of both very low density lipoprotein (10-30 mg/100 ml) and high density lipoprotein (5-10 mg/100 ml). The constituents of very low density lipoprotein, on a weight percentage basis, were found to be 48.1% triglyceride, 17.3% cholesterol ester, 8.8% cholesterol, 11.6% phospholipid, and 12% protein. These constituents were also present in high density lipoprotein with weight percentage values of 3.7%, 19.3%, 11.9%, 25.2%, and 36.8%, respectively. The fatty acid compositions of the triglycerides, cholesterol esters, and phosphatidylcholine were quite similar in the very low density lipoprotein and high density lipoprotein. However, shingomyelin fatty acid composition was appreciably different in the two lipoproteins. Disc gel electrophoresis in sodium dodecyl sulfate-polyacrylamide gels produced patterns with one major (approximate molecular weight, 7,000) and several minor bands for the apoprotein of very low density lipoprotein and one major (approximate molecular weight, 28,000) and several minor bands for that of high density lipoprotein.

Animals↗
PubMed1972

Composition of fatty acids and carbohydrates in Leptospira.

The fatty acid and monosaccharide composition of four pathogenic and two saprophytic strains of Leptospira was analyzed by gas chromatography (GC) and GC-mass spectrometry. Among the fatty acids, palmitic acid was most abundant and constituted 30 to 50% of the total fatty acids. Even-numbered unsaturated acids including octadecenoic, hexadecenoic, octadecadienoic, and tetradecadienoic acids comprised 40 to 60% of the total fatty acids. Tetradecanoic acid was about 5% in saprophytic strains, but 1% or less in pathogenic strains. The amount of chloroform-methanol extract of L. biflexa strain Ancona was 14 to 20% of the dry weight of the cell. Tetradecadienoic acid was found in the chloroform-methanol insoluble fraction, suggesting the presence of the acid in a bound form. GC analysis of monosaccharides revealed the existence of arabinose, xylose, rhamnose, mannose, galactose, glucose, glucosamine, and muramic acid in the cells. Among the neutral sugars, glucose was a minor component and was especially low in pathogenic strains. Total pentose content was about two to three times greater than total hexose.

Amino Sugars↗