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Biomedical subjects

E C McCoy

Publications and source records attributed to E C McCoy.

At least 55 records · Page 3Linked to original sources
PubMed1980

A bactericidal activity of microsomal preparations.

Exposure of suspension of Salmonella typhimurium tester strains TA1535, TA1537 and TA98 to mouse hepatic post-mitochondrial supernatants (S9) resulted in appreciable loss of bacterial viability. This lethal activity was destroyed by heating at 56 degrees C for 30 min. The toxic component of the S9 has not been identified.

Animals↗
PubMed1980

Non-mutagenic genotoxicants: novobiocin and nalidixic acid, 2 inhibitors of DNA gyrase.

The antimicrobial agents nalidixic acid and novobiocin, both inhibitors of DNA gyrase, preferentially inhibit the growth of DNA repair-deficient Escherichia coli, Salmonella typhimurium and Bacillus subtilis. On the other hand, these agents exhibit no demonstrable mutagenicity for S. typhimurium and E. coli even when tested under conditions designed to take the metabolic properties of these agents into consideration. Novobiocin and nalidixic acid are widely used in animal and human medicine and further studies to assess their genetic and carcinogenic potentials appear to be in order.

Bacillus subtilis↗
PubMed1979

Enhanced metabolism and mutagenesis of nitrosopyrrolidine in liver fractions isolated from chronic ethanol-consuming hamsters.

The effect of chronic ethanol consumption on the ability of isolated liver fractions to metabolize the carcinogen N-nitrosopyrrolidine (NPY) was examined. Microsomal fractions of treated animals exhibited increased rates of alpha-hydroxylation of NPY. Similar increases in the specific activities of aniline hydroxylase, reduced nicotinamide adenine dinucleotide phosphate cytochrome c reductase, and the specific content of cytochrome P-450 were also observed. In contrast, no differences in the specific activities of benzo(a)pyrene hydroxylase or glucose-6-phosphatase were observed. Liver postmitochondrial supernatants from ethanol-consuming animals were able to produce 5 times more mutants than did control preparations. It is concluded that alpha-hydroxylation of NPY is probably the mechanism by which NPY is converted to a mutagen and that this pathway can be induced by ethanol.

Alcoholism↗
PubMed1978

Microcapsule of Campylobacter fetus: chemical and physical characterization.

The antiphagocytic antigen (antigen [a]) comprising the microcapsule of a strain of Campylobacter fetus subsp. intestinalis has been purified from culture supernatants by ammonium sulfate fractionation and free-flow electrophoresis. Antigen [a] is a glycoprotein containing about 4% carbohydrate consisting of hexose, pentose, and methylpentose. The composition of the protein was typical of bacterial extramural structural proteins in its low content of basic, aromatic, and sulfur-containing amino acids. The protein had a high content of aspartic acid, threonine, glycine, and alanine. Antigen [a] had an Rf of 0.33 on polyacrylamide gel electrophoresis and a molecular weight calculated in sodium dodecyl sulfate-polyacrylamide gel electrophoresis of approximately 98,000. In contrast to its free form in culture supernatants, antigen [a] in vesicles derived from sheared cells appeared to exist in a complex with lipopolysaccharide. This complex could be dissociated by ethylenediaminetetraacetic acid or by ethylenediaminetetraacetic acid plus Triton X-100. A mutant strain that lacked a microcapsule, when incubated with soluble antigen [a] in a calcium medium, became agglutinable by monospecific [a] antiserum and showed an additional structural layer similar in appearance to the microcapsule on its cell wall. Points of similarity are emphasized between antigen [a] of C. fetus and the outer structural protein of the taxonomically related Spirillum serpens.

Agglutination↗
PubMed1978

Silver sulfadiazine: lack of mutagenic activity.

Silver sulfadiazine was found to be devoid of mutagenic potential in a sensitive mutagenicity assay using Salmonella typhimurium. In view of the close relationship between mutagenicity in this system and carcinogenicity in animals, these findings suggest that silver sulfadiazine is apparently also devoid of carcinogenic properties.

Mutagens↗
PubMed1978

Genetic activity of allyl chloride.

Allyl chloride (3-chloroprene) is mutagenic for Salmonella typhimurium and it induces gene conversions in Saccharomyces cerevisiae. It also displays DNA-modifying activity for E. coli. This is in contrast to a recent study which reported its lack of genetic activity for Salmonella typhimurium.

Allyl Compounds↗
PubMed1977

Activation of a procarcinogen to a mutagen by cell-free extracts of anaerobic bacteria.

The Salmonella mutagenicity assay can be coupled to cell-free preparations derived from anaerobic bacteria (Clostridium perfringens and Bacteroides fragilis) to activate a procarcinogen to a mutagen. This activity is destroyed by heating and by digestion with pronase and it is sensitive to oxygen. These findings indicate that the Salmonella mutagenicity assay can be adapted to the study of the role of anaerobes in the activation of carcinogens.

Aerobiosis↗
PubMed1976

Major outer membrane protein of Campylobacter fetus: physical and immunological characterization.

The outer membrane proteins of Campylobacter fetus have been isolated by extraction of cell envelopes both in Triton X-100 and ethylenediaminetetraacetate (EDTA) and in sodium dodecyl sulfate (SDS). Each method yielded a major protein component, which migrated identically in SDS-polyacrylamide gel electrophoresis (SDS-PAGE) and proved comparable in electrophoretic and molecular weight characteristics to the analagous protein from Escherichia coli. In addition, the surface of SDS-extracted C. fetus cells displayed a subunit structure similar to that observed in E. coli. The major envelope protein isolated with SDS appeared antigenically identical with one of the proteins isolated with Trition-EDTA on the basis of immunodiffusion reactions with specific antisera. Antibodies directed to the major envelope protein were not reactive in agglutination, immobilization, bactericidal, or opsonization reactions. Strains of C. fetus belonging to each of the three O serotypes possessed major envelope proteins comparable in SDS-PAGE but distinguished antigencally in a fashion paralleling the O serotype classification.

Antibodies, Bacterial↗
PubMed1976

Antibody-mediated immobilization of Campylobacter fetus: inhibition by a somatic antigen.

Immobilization tests were conducted on a wild-type strain of Campylobacter fetus subsp. intestinalis and on a mutant lacking an antiphagocytic cell surface component. Highly effective immobilization of the mutant, both as single cells and clumps of cells, was produced with an antiserum containing antibodies specific for the flagellar hook and filament and for the O antigen. Damage to flagellar hooks after reaction with this antiserum was observed only with cells of the mutant. Single-cell immobilization of the mutant was also produced with an antiserum specific for a heat-stable somatic antigen which was distinct from the O antigen and was exposed on the cell surface only of the mutant. Minimal immobilization of the wild strain was brought about by either of these antisera. It was shown also that O antibodies had no effect on the motility of either the wild strain or mutant. These findings indicate that antibody-mediated immobilization may be brought about by effects on the flagellar hook or cell body, as well as on the flagellar filament. Furthermore, the protection from immobilization afforded the bacterium by the antiphagocytic surface structure suggests a dual function for this virulence factor in the infected animal.

Animals↗
PubMed1975

Superficial antigens of Campylobacter (Vibrio) fetus: characterization of antiphagocytic component.

A glycoprotein responsible for the antiphagocytic properties of Campylobacter fetus has been identified by comparing cells of a wild-type strain with those of a mutant lacking this substance. The antiphagocytic component is demonstrable through electron microscopy as a discrete, negatively charged structure on the periphery of the cell. CLT is readily removed from the cell by mild extraction procedures and contributes to the inagglutinability in O antiserum normally displayed by C. fetus. Cells possessing this antigen are refractory to ingestion by macrophages except in the presence of specific antiserum. In its absence maximum phagocytosis occurs without a requirement for opsonins. It is concluded that the antiphagocytic component comprises a critical virulence factor of the bacterium.

Animals↗
PubMed1975

Flagellar ultrastructure and flagella-associated antigens of Campylobacter fetus.

Ultrastructural examinations of the flagellum of Compylobacter (Vibrio) fetus were performed throughout the growth cycle. Filament diameters, exceeding 17.6 nm during the exponential phase, were substantially greater than those reported for unsheathed flagella of other genera with the exception of Pseudomonas fluorescens. Filament diameters increased during growth, reaching a mean width of 21.2 nm in middle to late stationary phase. Internal flagellar structure, principally of the parallel lined variety, was observed during the later periods of growth but not during exponential or early stationary phase. Despite the unusually large filament sizes, no evidence of a flagellar sheath was observed after selected treatments (0.01 N HCl, 6 M urea, tris(hydroxymethyl) amino-methane-hydrochloride buffer, warm water) or examination of thin sections. To determine whether alterations in filament size and variable ability to demonstrate filament fine structure were correlated with progressive changes in serological activity, agglutination and immobilization tests were conducted with antisera directed against intact flagella, the principal flagellar antigen, the O antigen, and a superficial glycoprotein which has been found in association with the flagellum and the cell envelope. Significant differences in the serological activity of cells at different growth intervals were not noted with any of the sera employed.

Agglutination Tests↗