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Biomedical subjects

N Shaw

Publications and source records attributed to N Shaw.

At least 55 records · Page 3Linked to original sources
PubMed1982

Glycolipids from some extreme thermophilic bacteria belonging to the genus Thermus.

The lipids of Thermus aquaticus YT1, Thermus thermophilus HB8, Thermus sp. strains H and J (from Icelandic hot springs), and Thermus sp. strain NH (from domestic hot water) have been investigated. Each strain contained two major components, a glycolipid and a glycophospholipid, which have been isolated and analyzed. All of the strains contained as the principal component (41 to 57% of total lipid) a diacyldiglycosyl-(N-acyl)glycosaminylglucosylglycerol, but the five glycolipids differed in carbohydrate composition. The glycophospholipid appeared to be identical in each strain and contained an N-acylglucosamine residue. The principal fatty acids were C15 and C17 branched-chain compounds. This unique polar lipid composition should be of value in the classification of other thermophiles in the genus Thermus. The exceptionally high carbohydrate content of the lipids of these extreme thermophiles may be of significance in relation to the molecular basis of thermophily.

Carbohydrates↗
PubMed1979

Disruption of taste aversion learning by pentylenetetrazol.

Rats were taught an aversion to a sucrose taste cue (CS) by pairing it with lithium chloride-induced toxicosis (UCS). The CS-UCS interval was 30 min. Animals were injected with pentylenetetrazol (PTZ) (50 mg/kg at 0, 15, 25, 28 or 30 min after the CS in an attempt to disrupt taste aversion learning. Only animals given PTZ 30 min after the CS (simultaneously with the UCS) showed a significant learning deficit. However, learning deficits were also observed in individual animals in groups given PTZ at 15, 25 and 28 min. As lithium salts may produce seizures and abnormal electroencephalographic activity, it is suggested that the neurophysiological consequences of PTZ administration may interact with those of LiCl, causing a greater amnesic effect than PTZ by itself. The resulting interference with the memory trace is probably affecting either the neural engram underlying the CS or the associative bond between the CS and UCS. Evidence was also found that PTZ could act as a UCS with which to establish a mild taste aversion.

Animals↗
PubMed1979

Effects of jet noise on mortality rates.

Two areas, containing a total of over 160,000 people, were examined for mortality rates; one area was directly under incoming flights, near Los Angeles International Airport (LAX). The other was removed from the LAX flight patterns so that jet noise was not dominant. The two areas were chosen so that they were as nearly alike as possible in age, racial distribution, income and in other relevant factors with the sole major difference of jet noise in one of them. It was found that there was a substantial increase in mortality rates in the area under the jets where there was large noise radiation. In particular, by a most conservative statistical treatment there was in the jet noise area: a 15% increase in deaths due to strokes (cerebro-vascular disease) which accounted for 39 deaths in the two-year period of the study--presumably attributable to the excessive jet noise. Further, in the noise-radiated area there was a 100% increase in deaths due to cirrhosis of the liver (primarily attributed to alcoholism)--amounting to 24 extra deaths in the two years, due to jet noise. One of the disturbing side results of this study was that in these relatively poor regions it appears that there should be about 50% more deaths than were reported and recorded by Los Angeles County. These losses were perhaps due to a concentration of bad, given addresses in the areas in question; this serious loss casts grave doubt on previous studies of eath rates for minority peoples (e.g. blacks), suggesting that the rates may be considerably higher than those previously reported.

Aircraft↗
PubMed1974

The reaction of phosphoglycolipids and other lipids with hydrofluoric acid.

1. The use of HF as a dephosphorylating reagent for phospholipids was examined. 2. Hydrolysis of phosphatidylethanolamine at 0 degrees C for 24h with 60% HF gives a good yield of diglyceride. Under similar conditions phosphatidyldiglucosyl diglyceride gives diglyceride and diglucosyl diglyceride. 3. The glycolipid is also obtained from hydrolysis of glycerylphosphoryldiglucosyl diglyceride. No lyso derivative of the glycolipid could be detected and the glycosidic linkage was also stable. 4. Triglycerides, unsaturated and cyclopropane fatty acids were unaffected by the reagent. 5. 1,2-Diglycerides and 1,3-diglycerides were partially isomerized and also gave small amounts of free fatty acid and monoglyceride. 6. Monoglycerides underwent extensive rearrangement to form 1,2- and 1,3-diglycerides. 7. Lysophosphatidylethanolamine also gave 1,2- and 1,3-diglycerides as well as monoglycerides. 8. The application of this procedure to the structure determination of various phosphoglycolipids is discussed.

Acids↗
PubMed1972

The structure of a glycerylphosphoryldiglucosyl diglyceride from the lipids of Acholeplasma laidlawii strain B.

1. The phosphatidylglucose structure proposed previously (Smith & Henrikson, 1965) for the glucose-containing phospholipid from Acholeplasma laidlawii is incorrect. 2. The structure now proposed is 3-(sn-glycerol-3-phosphoryl-6'-[O-alpha-d-glucopyranosyl-(1-->2)-O-alpha-d-glucopyranosyl])- sn-1,2-diglyceride, a new type of bacterial lipid. 3. Deacylation of the lipid gave a single water-soluble phosphate ester which could be distinguished on chromatography from synthetic samples of glucosylphosphorylglycerols. 4. Hydrolysis of the lipid with alkali gave a mixture of fatty acids, glycerol 2-phosphate, sn-glycerol 3-phosphate and O-alpha-d-glucopyranosyl-(1-->2)-O-alpha- d-glucopyranosyl-(1-->1)-d-glycerol. 5. The lipid was unaffected on incubation with phospholipases A, C and D. 6. Diglucosyl diglyceride was isolated after treatment of the lipid with 60% HF, establishing the location of the fatty acid residues. 7. Periodate oxidation studies showed that the sn-glycerol 3-phosphate was esterified to the 6-hydroxyl group of one of the glucose residues in diglucosyl diglyceride.

Acholeplasma laidlawii↗
PubMed1971

Lipid composition of some species of Arthrobacter.

The lipids from Arthrobacter crystallopoietes, A. pascens, and A. globiformis were investigated. Each strain contained three glycolipids, a monogalactosyl diglyceride, a digalactosyl diglyceride, and a dimannosyl diglyceride, and traces of triand tetraglycosyl diglycerides. The phospholipids in all three strains consisted of bisphosphatidylglycerol, phosphatidylglycerol, and phosphatidylmyoinositol. No evidence could be obtained for the occurrence of mannophosphoinositides. Analysis of the fatty acids by gas-liquid chromatography showed that they are predominantly C(15:0)anteiso and C(17:0)anteiso compounds. No significant differences were observed in the composition of lipids extracted from homogeneous cell preparations of the rod and sphere forms of A. crystallopoietes.

Arthrobacter↗
PubMed1969

The structure of an acylated inositol mannoside in the lipids of propionic acid bacteria.

1. Lipids were extracted from five strains of Propionibacterium with chloroform-methanol mixtures and fractionated by chromatography on silicic acid. 2. All five extracts contained a glycolipid composed of fatty acids, inositol and mannose in the molar proportions 2:1:1. 3. Hydrolysis of the glycolipid with alkali gave a mixture of fatty acids and O-alpha-d-mannopyranosyl-(1-->2)-myoinositol. 4. Analysis of the fatty acids by g.l.c. showed that they were predominantly straight- and branched-chain isomers of pentadecanoic acid and heptadecanoic acid. 5. The location and distribution of the fatty acid residues in the molecule was established by periodate oxidation studies and mass spectrometry. The structure of the major glycolipid is 1-O-pentadecanoyl-2-O-(6-O-heptadecanoyl-alpha-d-mannopyranosyl)myoinositol. 6. The glycolipids are located in the membrane; the cell walls are devoid of lipid. 7. Possible functions of the glycolipid are discussed.

Cell Wall↗