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R D Hinsdill

Publications and source records attributed to R D Hinsdill.

32 records · Page 2Linked to original sources
PubMed1975

Biological activity of staphylococcin 162: bacteriocin from Staphylococcus aureus.

Staphylococcin 462 is a proteinaceous inhibitor produced by Staphylococcus aureus strain 462. In broth cultures, susceptible S. aureus strain 140 and 19 respond to treatment with the bacteriocin by stopping growth and cell division. Examination of macromolecular synthesis by measuring the incorporation of radioactive precursors revealed that S. aureus 140 stops synthesizing protein immediately. After exposure to staphylococcin 462, the synthesis of deoxyribonucleic acid and ribonucleic acid is quickly inhibited also, but not as completely. Treatment of S. aureus 140 with the inhibitor causes a rapid drop in cellular adenosine 5'-triphosphate level to about 60% of control levels. Of the 70 strains of gram-positive bacteria tested for susceptibility to staphylococcin 462, 24 (34%), distributed among 7 genera, were susceptible.

Bacteria↗
PubMed1975

Production and mode of action of lactocin 27: bacteriocin from a homofermentative Lactobacillus.

Lactobacillus helveticus strain LP27 produced a bacteriocin, lactocin 27, in dialyzable and nondialyzable forms. No evidence was obtained to indicate that lactocin 27 was under the control of extrachromosomal plasmids. Lactocin 27 had a bacteriostatic effect on the indicator, Lactobacillus helveticus strain LS18. It inhibited primarily protein synthesis without affecting deoxyribonucleic acid and ribonucleic acid synthesis or adenosine 5'-triphosphate levels. Treatment of susceptible cells with the lactocin did not cause leakage of ultraviolet-absorbing material, but caused the efflux of potassium ions and the influx of sodium ions. It adsorbed non-specifically to various bacterial species irrespective of their susceptibility to lactocin 27. However, the presence of specific receptors has not been ruled out.

Adenosine Triphosphate↗
PubMed1975

Alterations in mouse macrophage migration: a function of assay systems, lymphocyte activation product preparation, and fractionation.

Supernatants from mouse spleen cell and peritoneal cell cultures were tested for the presence of lymphocyte activation products. Supernatants from mouse spleen cell and peritoneal cell cultures incubated with brucella antigens contained a macrophage migration inhibition factor(s) and a macrophage spreading factor(s) only if the cells were harvested from Brucella-infected mice. After dialysis and freeze-drying, the supernatants were fractionated by preparative acrylamide-gel electrophoresis. Three fractions with lymphocyte activation product activity were obtained from the fractionated supernatants of mouse spleen cells and peritoneal cells harvested from Brucella-infected mice and cultured with brucella antigen. One fraction inhibited mouse macrophage migration from capillary tubes but not from agarose wells. A second fraction not only inhibited macrophage migration from both agarose wells and capillary tubes, but also contained an activity(s) that stimulated macrophage migration through Nuclepore filters and induced macrophage spreading. A third fraction timulated macrophage migration from agarose wells and also contained an activity(s) that stimulated macrophage migration through Nuclepore filters. Fractionated supernatants of mouse spleen cells and peritoneal cells harvested from uninfected mice incubated with and without brucella antigen, as well as of cells harvested from infected mice and not incubated with antigen, did not contain detectable lymphocyte activation products.

Antigens, Bacterial↗
PubMed1974

Isolation of substances responsible for lymphokine activity from sensitized mouse spleen cells.

Cultures of brucella-sensitized mouse spleen cells exposed to Brucella abortus antigens in vitro release macrophage migration inhibition factor (MIF) and macrophage spreading factor. Subjecting the supernatants from such cultures to preparative scale electrophoresis in acrylamide gel yields several fractions, one of which contains both MIF and macrophage spreading factor. This material has properties attributable to guinea pig MIF: it is nondialyzable, heat stable, nontoxic to macrophages from heterologous murine donors, and has a greater anodal electrophoretic mobility than guinea pig serum albumin. Another fraction from the gel column inhibits macrophage spreading; its electrophoretic mobility is similar to that of guinea pig gamma globulin. Neither brucella antigen nor skin reactive substances were detectable in any acrylamide gel column fraction when tested by the mouse footpad induration assay technique.

Animals↗
PubMed1973

Isolation and characterization of a bacteriocin from a homofermentative Lactobacillus.

Nearly 100 isolates of Lactobacillus were obtained from human and animal sources. Screening tests with the isolates revealed seven possible bacteriocinogenic strains and 26 strains sensitive to one or more of these inhibitory strains. Three homofermentative strains were selected for additional study after it was shown that their inhibitory substances differed in activity spectrum and in susceptibility to inactivation by proteolytic enzymes. One of these, L. helveticus strain LP27, was shown to produce a potent bacteriocin called lactocin 27. The lactocin was isolated from the culture supernatant fluid as a protein-lipopolysaccharide complex. In the presence of sodium dodecyl sulfate the complex was dissociated, and the activity was found to reside in a small glycoprotein (molecular weight 12,400). The amino acid composition of purified lactocin 27 is similar to that of the L. fermenti bacteriocin; neither requires disulfide bonds for activity.

Bacteriocins↗
PubMed1973

Characterization of a bacteriocin from Staphylococcus aureus strain 462.

Staphylococcus aureus 462 is one of three bacteriocin-producing strains selected for study from 200 isolates of staphylococci of animal origin. These bacteriocins are specific in their activity, inhibiting the growth of certain strains of S. aureus and other gram-positive species, but not gram-negative organisms. Staphylococcin 462 was not found in significant concentrations in the supernatant fluid of broth cultures, nor was it released into the suspending liquid when the cells were mechanically disrupted. However, extraction of the cells with 7 M urea resulted in the liberation of much of the activity. The material was purified by gel permeation chromatography by using Sephadex G-200 and by preparative electrophoresis on polyacrylamide gels in the presence of sodium dodecyl sulfate. Chemical analysis showed that the material consisted of roughly 90% protein and 3% lipid. The molecular weight of sodium dodecyl sulfate-dissociated staphylococcin 462 was calculated to be about 9,000.

Bacteriocins↗
PubMed1972

Recall of acquired cellular resistance in mice by antigens from killed Brucella.

Mice infected with Brucella abortus 19 were challenged intravenously with Listeria monocytogenes. Spleen assays to determine the number of viable Listeria cells present revealed that these mice were highly resistant to Listeria when challenged on day 17 of the Brucella infection. Resistance was absent in mice challenged on the 5th day and was declining in mice challenged on the 33rd day. Resistance could not be detected by day 49 of the Brucella infection but could be recalled by the injection of antigens from smooth B. abortus 2308. Thus, extracted antigens appeared to be as effective in recall as the live cells used in earlier studies. Similar injections of extracts from rough B. abortus 45/20, or from B. ovis REO 198, were also effective in recalling resistance; this suggests that the smooth surface agglutinogen may be relatively unimportant in recall.

Animals↗
PubMed1970

Characterization of a Staphylococcus aureus bacteriocin.

The bacteriocin produced by a strain of Staphylococcus aureus has been isolated and designated staphylococcin (414), and a study was made of its chemical, physical, and biological properties. The staphylococcin is released in appreciable quantities after breakage of the cells and can be purified through differential centrifugation and column chromatography. In the native state, it appears to be a lipoprotein-carbohydrate complex with a molecular weight in excess of 200,000. The complex can be dissociated by sodium dodecyl sulfate into smaller subunits which retain activity. The gross chemical and physical properties of the bacteriocin closely resemble those ascribed to certain preparations of cell membranes. Staphylococcin (414) is not a lytic enzyme like lysostaphin and does not have the same spectrum of activity. Like other bacteriocins from gram-positive microorganisms, it does not inhibit any gram-negative bacteria, but does inhibit several other genera.

Acridines↗
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

Colicine K. VII. The transfer to type K colicinogeny to Shigella sonnei.

1. The transfer of type K. colicinogeny to Shigella sonnei Phase II has been described. 2. The colicine elaborated by this microorganism is a lipopolysaccharide-protein complex which resembles the somatic antigen of the noncolicinogenic parent. 3. Although the colicine K of Escherichia coli K235 and of Sh. sonnei differ both chemically and serologically, they resemble each other in that both elicit type K colicine-neutralizing antibodies and both have the same bactericidal specificity. 4. The nature of the chemical changes brought about in the somatic antigen of Sh. sonnei through the acquisition of colicinogeny remains unknown

Colicins↗
PubMedDate not supplied

An analysis of risk from exposure to aldicarb using immune response of nonuniform populations of mice.

The immunomodulation response of mice to low levels of aldicarb in drinking water was investigated in four series of studies. The splenic plaque forming cell (PFC) response to red sheep cells were measured for treatment levels of 0.01 to 1,000 ppb (micrograms/kg). Based on their beginning and end body weights, the animal populations were uniform in all series of tests, but based on their net body weights and PFC counts they were highly nonuniform in the 30 and 60 day tests and uniform in the 90 and 180 day tests. The mean PFC counts for animals in each treatment were calculated and compared with the mean PFC counts for animals in the controls in all four series of tests. This approach ignores the variability and nonuniformity in the animal population. The outcomes using this approach were stimulatory for the 30 and 60 day tests and inhibitory for the 90 and 180 day tests. An alternative approach was developed based on the analysis of the distributions of the relative PFC counts of each animal in a treatment with each animal in a control, and specifically addresses the variability and nonuniformity in animal population as integral parts of the analysis. The distribution peaks were estimated by maximum likelihood and kernel/bootstrap procedures and were used to summarize the tests. The outcomes were consistently inhibitory, indicating immune suppression. The outcome of this approach converged to the outcome of the mean PFC approach for the 90 and 180 day tests where the animal populations were uniform.

Aldicarb↗