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L S Baron

Publications and source records attributed to L S Baron.

77 records · Page 5Linked to original sources
PubMed1962

UTILIZATION OF CARBOHYDRATES AND METABOLIC INTERMEDIATES BY PILIATED AND NONPILIATED BACTERIA.

Wohlhieter, J. A. (Walter Reed Army Institute of Research, Washington, D.C.), C. C. Brinton, Jr., and L. S. Baron. Utilization of carbohydrates and metabolic intermediates by piliated and nonpiliated bacteria. J. Bacteriol. 84:416-421. 1962.-The rate of aerobic and anaerobic metabolism of piliated and nonpiliated bacteria was studied in an effort to determine whether the presence of these surface structures altered the metabolic activity of bacteria. Respiration was measured manometrically when various piliated and nonpiliated strains metabolized glucose and several Krebs-cycle intermediates. Spontaneously produced nonpiliated variants of piliated cells were examined, but no difference in the rate of either aerobic or anaerobic metabolism was observed. Piliated and nonpiliated recombinants of a mating of Escherichia coli and Salmonella typhosa had different metabolic rates than the parent strains, but it was shown that these differences were not related to piliation. Clones of piliated and nonpiliated cells isolated from other crosses showed no difference between their respiration rate and that of either parent. Piliated and nonpiliated strains could mutate to higher rates of substrate utilization with no concomitant change in piliation. Since respiration and piliation can mutate independently and segregate independently in genetic crosses, we therefore conclude that there is no direct physiological relationship between them.

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PubMed1962

EPISOMIC ELEMENT IN A STRAIN OF SALMONELLA TYPHOSA.

Falkow, Stanley (Walter Reed Army Institute of Research, Washington, D.C.) and L. S. Baron. Episomic element in a strain of Salmonella typhosa. J. Bacteriol. 84:581-589. 1962.-An episomic element, F(0)-lac(+), has been identified in a strain of Salmonella typhosa isolated from a natural habitat. The F(0)-lac(+) element is transferred at high frequency as a single unit of transmission and replication without linkage to any other genetic character. Cells receiving F(0)-lac(+) are heterogenotes as if F(0)-lac(+) is not integrated as part of the linear structure of the chromosome, but rather replicates autonomously or in some other association with the genome. Evidence from complementation tests and transduction experiments is presented that the lac genes carried by F(0) are identical or at least markedly similar to the lac genes of Escherichia coli K-12. The F(0) transmission factor cannot be precisely identified but it does not appear to be phage or colicin. F(0) does exhibit mutual repression with the sex factor, F, of E. coli, and immunological experiments indicate some relationship between F and F(0).

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PubMed1962

GENETIC HOMOLOGY BETWEEN ESCHERICHIA COLI K-12 AND SALMONELLA.

Falkow, Stanley (Walter Reed Army Institute of Research, Washington, D.C.), Robert Rownd, and L. S. Baron. Genetic homology between Escherichia coli K-12 and Salmonella. J. Bacteriol. 84:1303-1312. 1962.-Recombinant analysis and interrupted mating procedures, in conjunction with molecular hybridization experiments, demonstrated that the genetic homology between Escherichia and Salmonella is incomplete. The most likely explanation of this incomplete homology is imperfect pairing between the deoxyribonucleic acid molecules of the two species. Despite the inhomologies, there is ample evidence that the order and distance of the genetic characters on the Salmonella chromosome are identical to those of Escherichia.

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