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Biomedical subjects

D T Berman

Publications and source records attributed to D T Berman.

48 records · Page 3Linked to original sources
PubMed1970

Preparation of Cell Wall Antigens of Staphylococcus aureus.

Cell walls were prepared from Staphylococcus aureus strains Copenhagen and 263 by high-speed mixing in the presence of glass beads followed by differential centrifugation. Insoluble peptidoglycan complexes were derived from cell walls by extraction of teichoic acid with 10% trichloroacetic acid. Intact teichoic acid was prepared from each strain by digestion of cell walls with lysostaphin and isolated by column chromatography. Soluble glycopeptide (peptidoglycan in which only the glycan has been fragmented) and the stable complex of teichoic acid with glycopeptide were prepared by digestion of cell walls with Chalaropsis B endo-N-acetylmuramidase and were separated by column chromatography. Amino acid and amino sugar contents of walls and subunits of walls were comparable to those reported by others.

Journal Article↗
PubMed1970

Isolation and characterization of a bacteriophage for Vibrio fetus.

Bacteriophages were isolated from 22 of 38 strains of Vibrio fetus by an enrichment process, utilizing the donor and host strains growing together in fluid thioglycollate medium. One phage, V-45, isolated by the conventional lawn-spot method, was characterized by stability in broth, growth kinetics, and morphology. It was sensitive to rapid thermal inactivation, chloroform, and pH values above 6.5. Calcium was required for phage replication and stability in broth. Magnesium provided the best protection against thermal inactivation at 50 C in the pH range of 6.5 to 7.5. The minimum latent period was 135 min, rise time was 75 min, and average burst size was 35 plaque-forming units per infected cell. Phage V-45 resembled Bradley's morphological group B, having a long tail without contractile sheath. Dimensions were: head, about 50 nm; tail, about 7 by 240 nm; and tail lumen, 2 to 3 nm.

Bacteriophages↗
PubMed1970

The susceptibility of muskrats and snowshoe hares to experimental infection with a chlamydial agent.

Muskrats (Ondatra zibethicus) and snowshoe hares (Lepus americanus) were exposed experimentally by various routes to a chlamydial agent (designated strain M56) originally isolated during a die-off of muskrats and snowshoe hares which occurred in Saskatchewan during 1961. Both species were susceptible to experimental infection. Whereas M56 was highly lethal for snowshoe hares (18 deaths/19 exposed), it was less virulent for muskrats (6 deaths/20 exposed). The degree of susceptibility of muskrats to induced infections with M56 was influenced by the presence or absence of specific antibodies at the time of exposure. A febrile illness was observed in 11 of 20 muskrats. In the six that died, widespread focal necrosis was found in the liver. Following intraperitoneal or oral exposures, chronic infections were established and the agent was recovered from the brain and the small intestine up to 96 days post-infection. Specific antibodies were found in 11.8% of 127 sera of muskrats trapped form the wild in Saskatchewan, the Canadian Arctic, and Wisconsin. In snowshoe hares, M56 induced an acute, febrile, emaciating illness, and the almost invariable fatal course was short with terminal signs of opisthotonos, convulsions, and hypoglycemia. Snowshoe hares succumbed with intravenous doses of less than ten mouse intracerebral LD(50) of M56. The same syndrome was produced by intravenous, subcutaneous, and oral infections. M56 was found in high titers in all tissues examined. The highest titers were found in the liver and spleen which correlated with the pathology observed. M56 was recovered from female rabbit ticks (Haemaphysalis leporispalustris) engorging on experimentally infected snowshoe hares.

Animal Diseases↗
PubMed1967

Antigens of Brucella abortus. I. Chemical and immunoelectrophoretic characterization.

Extracts of Brucella abortus 2308S, prepared either by aqueous extraction of sonically ruptured cells or by phenol-water extraction of whole cells, were subjected to various fractionation procedures and then analyzed to determine their immunoelectrophoretic patterns and chemical properties. Fraction A, prepared from sonic extracts, contained at least nine precipitable components when analyzed by immunoelectrophoresis. Of these, five components gave reactions of nonidentity with each other and, hence, represented separate antigens having unrelated determinant groups. Antigenic component IX, found in both the phenol and sonic extracts, did not form a precipitin line in the presence of serum that had been adsorbed with whole cells and was therefore tentatively identified as a "surface" antigen. From several lines of evidence, component IX was thought to be a lipopolysaccharide similar to the AP substance described by Miles and Pirie and shown by them to carry the "abortus" and "melitensis" determinant groups.

Antigens↗
PubMed1966

Agents of psittacosis-lymphogranuloma venereum group isolated from muskrats and snowshoe hares in Saskatchewan.

Agents lethal to chicken embryos and mice were isolated from the blood and spleen of 2 muskrats and 2 snowshoe hares which died during the cataclysmic die-off of 1961 in Central Saskatchewan. The 4 isolates are probably identical. One of them was identified as a member of the psittacosis-lymphogranuloma venereum (PLV) group of organisms on the basis of morphological and tinctorial properties and on the possession of group specific antigens. Application of the method of specificity differences permitted its serotype differentiation.

Animals↗