Search PubMed⌕ Search

Biomedical subjects

M J ALLISON

Publications and source records attributed to M J ALLISON.

28 records · Page 2Linked to original sources
PubMed1962

The correlation of a biphasic metabolic response with a biphasic response in resistance to tuberculosis in rabbits.

We have found a phase of susceptibility associated with a reduced metabolic activity on the part of peritoneal mononuclear phagocytes taken from BCG-vaccinated rabbits. A second stage of heightened resistance to infection was found to be associated with a heightened metabolic activity. The period of susceptibility in BCG vaccination is primarily concerned with initiation of the infection and not with the progression of the disease, which in both stages is increased. These reactions are discussed in relation to other conditions, such as nonspecific protein therapy and the administration of endotoxin, which also have similiar biphasic stages of resistance. Of incidental interest is the fact that rabbits who received 400 roentgen units are two years later still unable to respond to BCG vaccination with an increase in resistance. We conclude that there is a relationship between the level of certain metabolic activities of reticuloendothelial cells and resistance to tuberculosis.

Animals↗
PubMed1962

Studies on the metabolic function of branched-chain volatile fatty acids, growth factors for ruminococci. I. Incorporation of isovalerate into leucine.

Allison, Milton J. (Dairy Cattle Research Branch, U. S. Department of Agriculture, Beltsville, Md.), M. P. Bryant, and R. N. Doetsch. Studies on the metabolic function of branched-chain volatile fatty acids, growth factors for ruminococci. I. Incorporation of isovalerate into leucine. J. Bacteriol. 83:523-532. 1962.-Ruminococcus flavefaciens strain C94, a cellulolytic rumen bacterium, requires either isobutyrate or isovalerate for growth. The organism was grown in the presence of C(14)-labeled isovalerate, and the metabolic fate of the labeled carbon was studied to obtain information on the functions of this growth factor. Radioactivity from isovalerate-1-C(14) and isovalerate-3-C(14) was found mainly in the protein and lipid fractions of the cells. The C(14) in protein was all in leucine, indicating that a function of isovalerate was to serve as a carbon skeleton for leucine synthesis. As C(14) in leucine synthesized from isovalerate-1-C(14) was entirely in carbon 2, the intact isovalerate molecule was apparently incorporated into leucine. This is evidence that leucine was synthesized by a mechanism different from that previously demonstrated in other microorganisms.R. flavefaciens has a definite but limited ability to incorporate exogenous amino acids, including leucine. It incorporated 2% of the C(14) during growth in uniformly labeled (UL) C(14)-Chlorella protein hydrolyzate; Escherichia coli incorporated 37% of the label under similar conditions. In another experiment, a limited amount of exogenous leucine-2-C(14) was incorporated into protein of R. flavefaciens. The requirement for isovalerate was not replaced by dl-leucine or 2-ketoisocaproate. It is suggested that isovalerate or isobutyrate is required because R. flavefaciens has a limited ability to incorporate exogenous branched-chain amino acids and a limited ability to synthesize the isopropyl group found in these amino acids and in other components of the cell.

Amino Acids↗
PubMed1962

Metabolic function of branched-chain volatile fatty acids, growth factors for ruminococci. II. Biosynthesis of higher branched-chain fatty acids and aldehydes.

Allison, M. J. (Dairy Cattle Research Branch, USDA, Beltsville, Md.), M. P. Bryant, I. Katz, and M. Keeney. Metabolic function of branched-chain volatile fatty acids, growth factors for ruminococci. II. Biosynthesis of higher branched-chain fatty acids and aldehydes. J. Bacteriol. 83:1084-1093. 1962.-A number of strains of rumen bacteria require branched-chain volatile fatty acids for growth. A strain of Ruminococcus flavefaciens that requires either isovalerate or isobutyrate incorporates radioactive carbon from isovalerate-1-C(14) and isovalerate-3-C(14) into leucine and into the lipid fraction of the cells. Evidence obtained by both paper and gas chromatography indicated that most of the label in the lipid of cells grown in isovalerate-1-C(14) was in a branched-chain 15-carbon fatty acid, with some in a 17-carbon acid; about 7.5% of the C(14) was recovered in a branched-chain 15-carbon aldehyde. The aldehydes were in the phospholipid fraction and were presumably present as plasmalogen.A strain of R. albus was shown to require isobutyrate, 2-methyl-n-butyrate, or 2-ketoisovalerate for growth. This strain did not incorporate appreciable C(14) from isovalerate-1-C(14) or isovalerate-3-C(14). When grown in a medium containing isobutyrate-1-C(14), most of the cellular C(14) was found in the lipid fraction. Analysis of the lipid demonstrated that the label was present mainly as branched-chain 14-carbon and 16-carbon fatty acids, with 11% of the C(14) present in 14- and 16-carbon carbonyl compounds, presumably branched-chain aldehydes.Branched-chain 14-, 15-, and 16-carbon fatty acids are major components of the lipids of these rumen bacteria. The possibility that these acids and aldehydes, which are found in ruminant body and milk lipids, may be of microbial origin is discussed.

Aldehydes↗