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Biomedical subjects

M J Allison

Publications and source records attributed to M J Allison.

At least 109 records · Page 6Linked to original sources
PubMed1974

Pulmonary infection due to disruption of the pharyngeal bacterial flora by antibiotics in hamsters.

An animal model was used to determine the effect of oxacillin on the pharyngeal bacterial flora and the relationship of this flora to pneumonia. The pharyngeal bacterial flora of 68 healthy Golden Syrian hamsters was determined. A quantitative comparison between Streptococci and Escherichia, Proteus, Klebsiella and Enterobacter from 70 hamsters was made before and at 4, 24, 48 and 72 hours after oxacillin administration. Lung cultures were positive in 22 of 25 hamsters, yielding K pneumoniae type 1 most frequently. Lung histology from 25 hamsters revealed bronchopneumonia. Intestinal postmortem cultures of treated and untreated animals were similar. The importance of throat cultures in diagnosing pneumonia and the value of the hamster model to study the effect of other antibiotics on the temporary flora are demonstrated.

Animals↗
PubMed1971

The biosynthesis of valine from isobutyrate by peptostreptococcus elsdenii and Bacteroides ruminicola.

1. Growing cultures of Peptostreptococcus elsdenii and Bacteroides ruminicola incorporate (14)C from [1-(14)C]isobutyrate into the valine of cell protein. With P. elsdenii some of the (14)C is also incorporated into leucine. 2. Crude cell-free extracts of both organisms in the presence of glutamine, carbon dioxide and suitable sources of energy and electrons incorporate (14)C from [1-(14)C]isobutyrate into valine but not into leucine. 3. With extracts of P. elsdenii treated with DEAE-cellulose the reaction is dependent on ATP, CoA, thiamin pyrophosphate, molecular hydrogen and a low-potential electron carrier (ferredoxin, flavodoxin or benzyl viologen). 4. The same extracts incorporate (14)C from NaH(14)CO(3) into valine in the presence of isobutyrate plus ATP, CoA, glutamine and ferredoxin; isobutyryl-CoA or isobutyryl phosphate plus CoA will replace the isobutyrate plus CoA and ATP. With acetyl phosphate in place of isobutyryl phosphate, (14)C is incorporated into alanine. With isovalerate or 2-methylbutyrate in place of isobutyrate, (14)C is incorporated into leucine and isoleucine respectively. 5. When carrier 2-oxoisovalerate is added to the carboxylating system (14)C from [1-(14)C]isobutyrate passes into the oxo acid fraction. 6. It is concluded that these two organisms form valine from isobutyrate by the sequence isobutyrate-->isobutyryl-CoA-->2-oxoisovalerate-->valine and that the reductive carboxylation of isobutyrate is catalysed by a system similar to the pyruvate synthetase of clostridia and photosynthetic bacteria.

Adenosine Triphosphate↗
PubMed1971

Correlation of staphylococcal bacteriophage types to L-form colony production.

The ability of 258 strains of Staphylococcus aureus and 132 strains of S. epidermidis to produce L-form colonies in a standard environment was investigated. Production of these colonies by S. aureus was correlated with their phage type. Phage type 7 strains produced L-form colonies in larger numbers and more consistently than those of phage type 80/81. No L-form colonies were produced by the S. epidermidis strains tested.

Journal Article↗
PubMed1970

Biosynthesis of alpha-ketoglutarate by the reductive carboxylation of succinate in Bacteroides ruminicola.

Experiments with growing cells and with cell-free extracts of Bacteroides ruminicola indicate that this anaerobic bacterium can synthesize alpha-ketoglutarate by a reductive carboxylation of succinate. When the organism was grown in medium containing succinate-1,4-(14)C, most of the radioactivity in cells was in the protein fraction and most of the (14)C in protein was in the glutamic acid family of amino acids (glutamate, proline, and arginine). When unlabeled succinate was added to culture medium containing glucose-U-(14)C, incorporation of radioactivity into the glutamic acid family of amino acids was greatly reduced. This supports the concept that succinate is an intermediate in synthesis of alpha-ketoglutarate. Cell-free extracts of the organism incubated with succinate-1,4-(14)C incorporated (14)C into amino acids and most of this was found in glutamate. The cofactors which stimulate glutamate synthesis from succinate by extracts from these cells appear to be similar to the factors that have been demonstrated with extracts from photosynthetic bacteria. The position of label in glutamate synthesized from succinate-1,4-(14)C, the probable absence of isocitric dehydrogenase, and studies with labeled citrate and with inhibitors of citric acid cycle enzymes support the concept of a reductive carboxylation of succinate as the only, or at least a major, mechanism for synthesis of alpha-ketoglutarate in this organism. This appears to be the first evidence for a net synthesis of alpha-ketoglutarate by this reaction in a nonphotosynthetic heterotrophic organism.

Bacteroides↗