Biomedical subjects

W G Iverson

Publications and source records attributed to W G Iverson.

4 recordsLinked to original sources

PubMed1977

Succession of Streptococcus bovis strains with differing bacteriophage sensitivities in the rumens of two fistulated sheep.

The bacteriophage sensitivity of the Streptococcus bovis population resident in the rumens of two fistulated sheep was monitored for 112 days. During this time, three changes in the bacteriophage sensitivity of S. bovis occurred in the absence of detectable bacteriophages. Identical changes in bacteriophage sensitivity occurred simultaneously in both animals and, except for the relatively short periods of changeover in phage sensitivity, the S. bovis population in the rumens of the two sheep was homogeneous with respect to phage sensitivity.

Animals↗

PubMed1976

Characterization of Streptococcus bovis bacteriophages.

About 25 Streptococcus bovis bacteriophages were isolated from abattoir wastes, bovine rumen fluid, and lysogenic strains of S. bovis. Eight phages were selected and characterized by morphology, stability, rate of adsorption, single-step growth curve, serum neutralization, and antigenic relationship. Two distinct morphological phage types were found, one of which has not been previously reported for group D streptococci.

Abattoirs↗

PubMed1976

Lysogeny in Streptococcus bovis.

Forty-eight strains of Streptococcus bovis were tested for induction with mitomycin C. Eleven inducible strains were found and the lysates of all 11 contained bacteriophage-like particles. The lysate of one strain also contained large numbers of particles which closely resembled polyheads. Eight of the lysates produced zones of inhibition on indicator strains and viable bacteriophages were detected in six lysates. The sources of the S. bovis were ovine and bovine rumen fluid (23 strains), ovine and bovine feces (5 strains), blood cultures from human endocarditis (8 strains), and a wide variety of other sources (12 strains). Only 1 of 23 rumen S. bovis strains was lysogenic, which suggests that lysogenic S. bovis strains are not an important source of bacteriophages in the rumen.

Animals↗

PubMed1976

Bacteriocins of Streptococcus bovis.

Forty-seven strains of Streptococcus bovis were tested for bacteriocin production. Fourteen were found to produce bacteriocins, while all 47 were sensitive to at least one of these bacteriocins. The bacteriocins, on the basis of their host range on S. bovis strains, formed six groups. A representative of each group was selected and characterized by temperature stability, sensitivity to trypsin and lipase, sedimentation by centrifugation, ability to pass through dialysis tubing, host range on other bacterial species, and conditions for production in liquid media. A correlation between mannitol fermentation and bacteriocin production was noted.

Bacteriocins↗