PubMed Health⌕ Search

Biomedical subjects

J N BALDWIN

Publications and source records attributed to J N BALDWIN.

At least 19 recordsLinked to original sources
PubMed1964

NATURE OF THE DETERMINANT CONTROLLING PENICILLINASE PRODUCTION IN STAPHYLOCOCCUS AUREUS.

Harmon, Shirley A. (Ohio State University, Columbus), and Jack N. Baldwin. Nature of the determinant controlling penicillinase production in Staphylococcus aureus. J. Bacteriol. 87:593-597. 1964.-From three penicillinase-producing strains of Staphylococcus aureus 38 penicillin-sensitive mutants were isolated. With phages 80 and 53 of the International Typing Series, each of these mutants was a competent recipient of the penicillinase marker from the parent strains. Although numerous reciprocal transductions were performed between penicillin-sensitive mutants, no penicillinase-producing recombinants were observed. Reversion of the penicillinase-negative mutants to capacity to produce penicillinase was never observed. When tested for 50 distinctive physiological characteristics, the mutants generally were similar to the parent strains except for resistance to penicillin. One penicillin-sensitive mutant failed to produce detectable amounts of five exoenzymes. By treating resistant strains with acridine orange, it was possible to isolate sensitive strains at a frequency that was 60 times greater than the spontaneous mutation rate. Thus, the determinant controlling the capacity of strains of S. aureus to produce penicillinase appears to be a cytoplasmic element.

Acridines↗
PubMed1964

PURIFICATION AND PROPERTIES OF STAPHYLOCOCCAL BETA-HEMOLYSIN. I. PRODUCTION OF BETA-HEMOLYSIN.

Haque, Riaz-ul (Ohio State University, Columbus), and Jack N. Baldwin. Purification and properties of staphylococcal beta-hemolysin. I. Production of beta-hemolysin. J. Bacteriol. 88:1304-1309. 1964.-Highest activity of beta-hemolysin was observed when buffered saline (pH 7.0) containing 0.001 m magnesium sulfate was used as a diluent, and the tubes were incubated at 37 C for 80 min and then refrigerated for 30 min. Either Heart Infusion semisolid agar or a dialysate of Heart Infusion containing 0.3% agar was suitable for the production of large quantities of beta-hemolysin. The concentration of beta-hemolysin in semisolid and broth cultures was greatest after incubation for 24 hr. Continued incubation resulted in a loss of active hemolysin in broth cultures but not in semisolid agar cultures. Incubation in atmospheres containing 20% carbon dioxide greatly enhanced the production of beta-hemolysin. The presence of fermentable sugars inhibited the production of beta-hemolysin. Highest yields of beta-hemolysin were obtained when the initial pH of the medium was 5.5 to 5.8.

Agar↗
PubMed1964

TYPES OF HEMOLYSINS PRODUCED BY STAPHYLOCOCCUS AUREUS, AS DETERMINED BY THE REPLICA PLATING TECHNIQUE.

Haque, Riaz-Ul (The Ohio State University, Columbus), and Jack N. Baldwin. Types of hemolysins produced by Staphylococcus aureus as determined by the replica plating technique. J. Bacteriol. 88:1442-1447. 1964.-The type of hemolysins produced by a representative number of cells of a culture of Staphylococcus aureus was determined by the replica plating technique, with the use of sheep, rabbit, human, and horse blood agar plates. Unless horse and human red blood cells were used, a distinction between alpha-and delta-hemolysins was difficult to make. Strains producing alpha-beta-, beta-delta-, and alpha-delta-hemolysins were recognized by the replica plating technique. A few colonies produced lysis of rabbit, horse, and human cells without lysis of sheep red blood cells. This pattern of lysis was not detected by the radial streak or the tube titration procedures when mixed populations were examined, and may be due to a lytic factor not hitherto described.

Animals↗
PubMed1962

Transduction of resistance to some macrolide antibiotics in Staphylococcus aureus.

Pattee, P. A. (Iowa State University, Ames) and J. N. Baldwin. Transduction of resistance to some macrolide antibiotics in Staphylococcus aureus. J. Bacteriol. 84:1049-1055. 1962.-By use of phage 80 of the International Typing Series, propagated on appropriate strains of Staphylococcus aureus, two related markers controlling resistance to certain macrolide antibiotics (erythromycin, oleandomycin, spiramycin, and carbomycin) were transduced among a variety of strains of S. aureus. Unlike the markers controlling penicillinase production and resistance to chlortetracycline and novobiocin, the determinants of resistance to the macrolide antibiotics were transduced at normal frequencies (at least 300 transductants per 10(9) phage) only to certain of the recipient strains. One of the markers studied appears to control an inducible enzyme system which is specifically induced by sub-inhibitory concentrations of erythromycin and which controls resistance to erythromycin, oleandomycin, spiramycin, and carbomycin. The other marker examined confers resistance to erythromycin, oleandomycin, spiramycin, and carbomycin, and shows no evidence of being dependent upon an inducible mechanism.

Anti-Bacterial Agents↗
PubMed1961

Transduction of resistance to chlortetracycline and novobiocin in Staphylococcus aureus.

Pattee, P. A. (Ohio State University, Columbus) and J. N. Baldwin. Transduction of resistance to chlortetracycline and novobiocin in Staphylococcus aureus. J. Bacteriol. 82: 875-881. 1961.-Using phage 80 of the International Typing Series propagated on appropriate strains of Staphylococcus aureus, resistance to chlortetracycline and novobiocin and the capacity to produce penicillinase were transduced to a number of antibiotic-sensitive recipient strains of S. aureus. The frequency of transduction varied from 1 to 10 transductants per 10(7) phage particles employed. Lysogenization of the transductants by the transducing phage did not occur. Phages 29, 52A, 79, and 53 of the International Typing Series were also capable of transduction, while phages 42B and 81 were unable to participate under the conditions used. The recipient strains were either resistant or susceptible to lysis by the transducing phages, but this did not influence the transduction frequencies. Lysis of transductants susceptible to the transducing phages was inhibited by preparing the selective medium with brain heart infusion agar. Linked transductions were not detected. With few exceptions, all of the recipient strains were susceptible to lysis by phages of group I or phage 81 or both. Strains susceptible to lysis by phages of groups II and III, but resistant to lysis by phages of group I or phage 81, were not transduced.

Anti-Bacterial Agents↗