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J B EVANS

Publications and source records attributed to J B EVANS.

At least 19 recordsLinked to original sources
PubMed1963

COMPARATIVE PHYSIOLOGY OF ANTIBIOTIC-RESISTANT STRAINS OF STAPHYLOCOCCUS AUREUS.

Brown, Ruby L. (North Carolina State College, Raleigh) and James B. Evans. Comparative physiology of antibiotic-resistant strains of Staphylococcus aureus. J. Bacteriol. 85:1409-1412. 1963.-A collection of antibiotic-resistant strains of Staphylococcus aureus isolated from clinical sources was studied with respect to nutritional requirements and common diagnostic tests. Contrary to numerous reports in the literature indicating changes in these characteristics in antibiotic-resistant mutants, the present cultures were typical members of the taxonomic species S. aureus. They were coagulase-positive, fermented both glucose and mannitol under anaerobic conditions, produced acetoin from glucose, grew and produced black colonies on tellurite glycine agar, required both thiamine and nicotinic acid, and did not require other vitamins or purines. It is suggested that in most instances these cultures from clinical sources represent spontaneous mutants having genetic changes limited largely to loci concerned with antibiotic resistance. Most reports of extensive changes in physiology and nutritive requirements by antibiotic-resistant strains of S. aureus are based on studies of resistant strains selected after exposing a large population of the parent sensitive strain to toxic levels of antibiotics, chemical mutagens, or irradiation. Such isolates may have widespread genetic damage at other loci in addition to those concerned with their antibiotic resistance.

Anti-Bacterial Agents↗
PubMed1961

Role of potassium in the oxidative metabolism of Micrococcus sodonensis.

Perry, Jerome J. (The University of Chicago, Chicago, Ill.), and James B. Evans. Role of potassium in the oxidative metabolism of Micrococcus sodonensis. J. Bacteriol. 82:551-555. 1961.-An absolute potassium requirement has been established for the growth of Micrococcus sodonensis with lactate or pyruvate as substrate. Potassium at 0.67 x 10(-2)m concentration was necessary for maximal growth. Resting cell and cell-free preparations from cells grown on minimal levels of potassium were stimulated by potassium but, due to residual or bound cation, did not show an absolute requirement. Rubidium and cesium replaced potassium in these cells although cesium is much less effective.

Lactates↗
PubMed1961

Effect of ammonium ion on growth and metabolism of Micrococcus sodonensis.

Campbell, J. N. (American Meat Institute Foundation, Chicago, Ill.), James B. Evans, Jerome J. Perry, and C. F. Niven, Jr. Effect of ammonium ion on growth and metabolism of Micrococcus sodonensis. J. Bacteriol. 82:823-827. 1961.-When Micrococcus sodonensis was grown in a synthetic medium deficient in ammonia, large quantities of alpha-keto acids, chiefly alpha-ketoglutaric, accumulated in the medium. The addition of ammonium chloride to this medium prevented such accumulation and also supported increased growth, even in the presence of excess glutamate. Neither potassium nor sodium would substitute for ammonia in producing this effect. The results indicate that this microorganism has a specific requirement for the ammonium ion in its growth and metabolism. If not supplied exogenously, ammonia is made available by deamination of glutamic acid. The exact route of incorporation of ammonia is unknown.

Ammonium Chloride↗
PubMed1961

An extracellular material elaborated by Micrococcus sodonensis.

Campbell, J. N. (American Meat Institute Foundation, Chicago, Ill.), James B. Evans Jerome J. Perry, and C. F. Niven, Jr. An extracellular material elaborated by Micrococcus sodonensis. J. Bacteriol. 82:828-837. 1961.-When actively growing in a yeast extract-tryptone broth, Micrococcus sodonensis produced rather large quantities of an extracellular material. On a dry weight basis, this material consisted of approximately 80% deoxyribonucleic acid (DNA), 6% ribonucleic acid, 13% protein, and a small quantity of a cell pigment which contained an associated iron porphyrinlike compound. The extracellular material was not produced in other complex or synthetic media. Removal of cells from the appropriate growth medium and suspension in distilled water resulted in the prevention of formation of the material if it had not already begun, or its immediate cessation in those cells which had been actively producing the material. Cells producing the extracellular material exhibited an increasingly higher concentration of intracellular DNA as incubation proceeded, whereas cells growing under conditions not supporting such production showed a decline in intracellular DNA as the culture aged. A similar increase of intracellular DNA, but not release of extracellular material, could be effected by addition of yeast extract or high levels of purine compounds to a medium which did not support the production of extracellular material. The base composition and ratios of both extracellular and intracellular DNA produced under all conditions tested were compared and found to be similar or identical, and to correspond to the classical Watson-Crick structure for DNA.

Culture Media↗