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Biomedical subjects

F H White

Publications and source records attributed to F H White.

At least 91 records · Page 5Linked to original sources
PubMed1977

Production and characterization of Moraxella bovis hemolysin.

Moraxella bovis hemolysin was produced in trypticase soy broth and maximum hemolytic activity of the culture was observed during the logarithmic phase of growth. The hemolysin was filterable through a 0.22-micrometer (APD) membrane filter, heat labile, and destroyed by treatment with formalin or trypsin. There was no difference in the amount of hemolysin production by rough or smooth colony types of an isolate, although differences were observed between 2 different isolates. Partial requirement of a sulfhydryl group and divalent cations were suggestive of an enzymatic nature of M bovis hemolysin.

Calcium↗
PubMed1976

Salmonella and Aspergillus infections in common loons overwintering in Florida.

During a 5-year period (1970-1975), 190 common loons (Gavia immer) from overwintering populations on the east and west coasts of Florida were examined for evidence of infectious diseases. Salmonella spp (representing 8 serotypes) were isolated from 27 (14%) of the loons, and lesions typical of those produced by Aspergillus fumigatus were found in 34 (18%) of the loons. Seven loons were infected with Salmonella spp and had lesions typical of aspergillus infection. The largest number of loons (124) was obtained during the winter of 1973-1974, in connection with an offshore oil spill. There was no significant difference between the isolation rates of Salmonella spp from oiled vs nonoiled loons, but the occurrence of aspergillosis was higher in nonoiled than in oiled loons.

Animals↗
PubMed1976

Studies on secondary structure in chicken egg-white lysozyme after reductive cleavage of disulfide bonds.

Native lysozyme and three reduced derivatives (carboxymethyl, carboxamidomethyl, and triphenylethyl-phosphonium) were examined by circular dichroism, and fractions of the protein chain present as alpha-helix, beta structure, and unordered structure were estimated by a computeradapted curve-fitting program. The alpha helix ranged from 2 to 23% in the three products, while native lysozyme exhibited 26 to 31%. However, beta structure in the reduced samples occupied 23-62% of the chain length (the latter in 50% methanol), consistently in excess of the native content(11-16%). Secondary structure in the reduced samples increased with pH, while that of the native protein remained nearly constant. In 8 M urea alpha helix was mostly eliminated from the reduced protein, while beta structure was nearly unaffected. Qualitatively, a partial loss of beta structure appeared to result from peptic digestion of the reduced samples, with further loss on exposure of the digest to urea. Stability of the observed beta structure indicates its existence prior to the oxidation of SH groups, which is concomitant with development of the native conformation. This structure could, therefore, constitute at least part of a precursor conformation in the formation of native structure.

Amino Acids↗
PubMed1976

The structlre of pili (fimbriae) of Moraxella bovis.

Cells from rough and smooth colonies of Moraxella bovis were examined by electron microscopy utilizing both shadowing and thin sectioning techniques. Pili were found on the surfaces of cells from rough but not smooth colonies. Pili had a peritrichoud distribution and appeared as delicate (6.5-8.5 nm in diameter), elongated unbranched filaments. When bacteria were sectioned pili did not contain central pores and appeared to originate from opacities on the surface of the cell wall.

Animals↗
PubMed1976

Extracellular antigens of Moraxella bovis.

The extracellular antigens of 2 isolates of Moraxella bovis were isolated by ammonium sulfate precipitation of cell-free culture filtrate, purified by filtration and differentiated by immunodiffusion and immunoelectrophoretic techniques. The extracellular filtrate from rough types had 2 specific extracellular antigens in addition to those in the culture filtrate of smooth-type cells of the same isolate. The extracellular antigens produced by smooth-type cells were identical in all isolates of Moraxella bovis. The serotype-specific extracellular antigens of 2 isolates were serologically identical but were different from those of a 3rd isolate. The possibility of serotyping M bovis isolates, on the basis of their extracellular rough-type antigens, was suggested. Although both serotype-specific antigens were destroyed by trypsin treatment, 1 antigen was also heat-labile and partially destroyed by formalin treatment.

Antigens, Bacterial↗
PubMed1975

A microbiologic study of the urban gray squirrel.

Bacteriologic, virologic, and serologic examinations were conducted on 180 urban gray squirrels (Sciurus carolinensis) during a 1-year period in a metropolitan area. Evidence was not found of infections with leptospires, enteric or other bacteria, rickettsial agents, Francisella tularensis, or arthropod-borne viruses. The squirrels were remarkably free of evidence of bacterial or viral infections of importance to man and lower animals.

Animals↗
PubMed1975

Edwardsiella tarda infections in Florida racoons, Procyon lotor.

Edwardsiella tarda was isolated from the large intestine of seven (17%) of 42 racoons from Florida. The rate varied from 12% in South Florida to 25% in North Florida. In addition, 52% of the racoons examined were carrying Salmonella, with numerous serotypes represented.

Animals↗
PubMed1975

Intussusception in a Florida manatee.

An intussusception resulting from an embedded fishhook and a mass of nylon cord, monofilament line, and wire was determined to be the cause of death in a Florida manatee (Trichechus manatus latirostris). Pathologic findings are given along with information on bacteria (Edwardsiella tarda), pesticide residues (DDE, PCB's and dieldrin), and parasites (Chiorchis fabaceus).

Animals↗
PubMed1973

The biosynthesis of plasmodial myosin during starvation of Physarum polycephalum.

The actomyosin protein complex of Physarum polycephalum was prepared from vegetative and starved plasmodia. The yield of actomyosin per unit wet wt. was the same from both types of plasmodia. Myosin was resolved from the complex by gel filtration and purified by ion-exchange chromatography. The Ca(2+)-stimulated adenosine triphosphatase activities of myosin preparations from vegetative and starved plasmodia were not appreciably different. Synthesis of myosin de novo was shown to occur during the starvation phase of the life-cycle by the isolation of labelled myosin preparations from plasmodia starved in the presence of [2-(14)C]glycine. Fractionation of polyacrylamide gels after gel filtration of labelled myosin confirmed the presence of label in the adenosine triphosphatase-active myosin band. It is concluded that during starvation myosin synthesis continues although there is a net loss of approx. 50% of the total protein. Sodium dodecyl sulphate-polyacrylamide-gel electrophoresis of Physarum myosin showed the presence of low-molecular-weight components of the molecule, similar to those of muscle myosins. The content and composition of the free amino acid pool of Physarum was measured at various time-intervals during the vegetative and starvation phases of the life-cycle.

Actomyosin↗
PubMed1972

Evaluation of a macroscopic plate test and an indirect immunofluorescence test to detect leptospiral antibodies in bovine serum.

A macroscopic plate test was found to be reliable and convenient for detection of Leptospira serotype pomona antibodies in bovine sera. However, the procedure was unreliable for detecting L. serotype canicola antibodies because of false positive reactions. An indirect immunofluorescence test and the microscopic agglutination test provided comparable results and they effectively detected serotype pomona antibodies in bovine sera.

Agglutination Tests↗