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Biomedical subjects

G A Thompson

Publications and source records attributed to G A Thompson.

At least 217 records · Page 12Linked to original sources
PubMed1971

Studies of membrane formation in Tetrahymena pyriformis. II. Isolation and lipid analysis of cell fractions.

A method has been devised to fractionate cells of Tetrahymena pyriformis, yielding pure or highly enriched preparations of cilia, cilia-associated soluble material, pellicles, mitochondria, microsomes, and postmicrosomal supernatant. The method prevents the destructive action of lipolytic enzymes commonly associated with this organism. Analysis of the membrane lipids of these fractions reveals significant differences in lipid composition. Most noteworthy are the high concentrations of phosphonolipid and tetrahymanol in the surface membranes.

Animals↗
PubMed1971

Studies of membrane formation in Tetrahymena pyriformis. 3. Lipid incorporation into various cellular membranes of logarithmic phase cultures.

When 1-(14)C-palmitic acid is used to pulse label logarithmic cultures of Tetrahymena pyriformis, radioactivity appears in lipids of the various membrane types at vastly differing rates. The microsomes and postmicrosomal supernatant attain a high specific radioactivity within 1 min, while the membranes enveloping the cilia require several hours to reach the microsomal level. A similar pattern is obtained when the tracer is sodium 1-(14)C-acetate or 8,9-(3)H-hexadecyl glycerol. In all fractions the phosphonolipid incorporates radioactivity from (14)C-palmitate much less rapidly than do the other major phospholipids. The patterns of labeling suggest that new lipids are transported from a cytoplasmic site of synthesis to points of membrane fabrication throughout the cell.

Acetates↗
PubMed1970

Phosphonolipids: localization in surface membranes of Tetrahymena.

Approximately 60 percent of the phospholipids from the membrane sheath of Tetrahymena pyriformis cilia contain 2-aminoethylphosphonic acid. This is more than twice the concentration found in total cell lipids. The resistance of these lipids to hydrolytic enzymes suggests that they increase the stability of the surface membranes.

Carbon Isotopes↗
PubMed1968

Alpha tocopherol control of sexuality and polymorphism in the rotifer Asplanchna.

A dietary component that initiates both the tranisition from parthenogenetic to sexual reproduction and the production of lateral, posterodorsal, and posterior outgrowths of the body wall of females was isolated from the neutral lipids of dried grass and identified as (alpha)-tocopherol. The smallest concentrations eliciting both responses were below 100 nanograms per milliliter. Relative activities of (alpha)-, beta3-, and (gamma)-tocopherol and (alpha)-tocopheryl-quinone were roughly 100 : 100 : 20 : 0.4. The synthetic antioxidants tested were without activity.

Animals↗