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Biomedical subjects

A D Keith

Publications and source records attributed to A D Keith.

47 records · Page 3Linked to original sources
PubMed1971

Saturated fatty acid requirer of Neurospora crassa.

Dietary saturated fatty acids containing 12- to 18-carbon atoms satisfy growth requirements of Neurospora crassa mutant cel (previously named ol; Perkins et al., reference 11); unsaturated fatty acids are synthesized by direct desaturation when an appropriate saturate is available. Odd-chain saturates, 15 carbons and 17 carbons long, satisfy the requirement, and elaidic acid (18:1 Delta(9)trans) results in slow growth. Oleic acid and other cis-unsaturated fatty acids do not satisfy growth requirements; however, oleic acid plus elaidic acid result in growth at a faster rate than elaidate alone. The use of a spin-label fatty acid reveals that hyphae produced by cel during a slow basal level of growth have lipids that reflect a relatively rigid state of viscosity compared to wild type. cel Supplemented with fatty acids and wild type supplemented in the same way have lipids of the same viscosities as reflected by electron spin resonance.

Acetates↗
PubMed1970

Double-bond requirement in a fatty acid desaturase mutant of Saccharomyces cerevisiae.

A fatty acid Delta(9)-desaturase mutant of yeast was analyzed to establish the specificity of the fatty acid structural requirement. Several double-bond-containing and substituted fatty acids were tested. It was concluded that the presence of a Delta(9)cis double bond is necessary for growth. The need for a specific chain length or a specific number of double bonds, or for both, is more flexible. Tracer-containing 16:1Delta(9)cis, 18:1Delta(9)cis, 18:2Delta(9,12)cis,cis and 18:3Delta(9,12,15) all cis revealed that each of these growth-supporting components, once taken up, was not converted into other fatty acids. Concentration effects on doubling time were also considered.

Carbon Isotopes↗
PubMed1969

Fatty acid desaturase mutants of Saccharomyces cerevisiae.

Genetic and biochemical analyses were conducted on fatty acid mutants of yeast deficient for Delta(9)-desaturase activity in the production of palmitoleate and oleate. Two genetic loci were observed and two others are inferred; three of these were represented by respiratory-deficient (petite) strains. All strains were incapable of converting palmitate to palmitoleate and stearate to oleate whether the direct precursor or acetate was followed. All strains were capable of acylating both de novoproduced fatty acids and oleate taken up from the medium into phospholipids and neutral lipids. Two revertants were analyzed which differed in their ability to produce palmitoleate and oleate.

Acetates↗