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Biomedical subjects

H Brandis

Publications and source records attributed to H Brandis.

At least 73 records · Page 4Linked to original sources
PubMed1975

Purification and Characterization of two bacteriocins from Streptococcus faecium.

Two bacteriocins were found in the supernatant fluid and in an extract of Streptococcus faecium strain EI. The small soluble enterocin EIA represented more than 90% of the total activity in the supernatant fluid, and was purified 400-fold by ammonium sulphate fractionation, gel filtration on Sephadex G-75 and chromatography on DEAE-cellulose. Enterocin EIB, with a particle weight greater than 4 x 10(6), was the predominant type in the extract. It was released in appreciable quantities after breakage of the bacteria and was purified 100-fold by differential centrifugation, chromatography on Sepharose 4B and density gradient ultracentrifugation. Enterocin EIA, a basic substance with a molecular weight of about 10000, was resistant to heat and was attacked by trypsin, whereas enterocin EIB was less thermostable and insensitive to proteolytic enzymes. The activity of enterocin EIB was unchanged by treatment with DNAase. Sensitivity to enterocin action was confined to certain strains of various enterococcus species, Streptococcus salivarius and Listeria monocytogenes; all the other Gram-positive and Gram-negative bacteria tested for sensitivity were unaffected by either enterocin.

Ammonium Sulfate↗
PubMed1975

Mode of action of two streptococcus faecium bacteriocins.

The mechanism of action of enterocins E1A and E1B, bacteriocins produced by Streptococcus faecium E1, was studied. The enterocins killed susceptible cells rapidly, but cell lysis does not appear to be involved directly. Susceptible cells could be rescued from the lethal damage by trypsin treatment only within 2 to 3 min after addition of enterocin E1A. Enterocins E1A and E1B inhibited protein synthesis and drastically reduced biosynthesis of deoxyribonucleic acid (DNA) and ribonucleic acid (RNA) but did not cause degradation of DNA or RNA. Enterocin E1A strongly inhibited the accumulation of isoleucine and caused rapid exit of previously accumulated isoleucine.

Bacteriocins↗
PubMed1975

[Phage typing and biotyping of salmonella typhi-murium (author's transl)].

1998 strains of Salmonella typhi-murium from two different regions of West-Germany were investigated according to their biotype and phagetype. 132 strains were isolated from sewage, 320 strains from animals and the others from human beings. 60 different phagetypes were found. The phagetype 49 occurred most often (11,9% resp. 10,3%). A correlation between biotype and phagetype could not be observed. Nearly every phagetype could be divided into several biotypes. However, only few biotypes prevaled. These comprised the biotypes 1, 10 and 17. The examination of the splitting of trehalose was useful in the biochemical differentiation. Concerning strains of animal origin it was remarkable that most strains from cattle resp. calves belonged to the phagetype 49. Among 145 strains from pigeons 95,9% could be classified as phagetype 2. With exception of 3 strains all the other strains from pigeons did not possess the O-antigen 5. The majority of the strains belonged to the biotype 8. All these strains could not split maltose.

Animals↗
PubMed1975

Cytotoxicity mediated by soluble macrophage product(s).

The soluble macrophage product(s) released by nonimmune mouse peritoneal macrophages exposed to endotoxin or from listeria-immune macrophages after incubation with specific antigen mediated cytotoxic activity against malignant cell types and, to a lesser extent, against normal cells. Only undiluted supernatants from nonimmune or listeria-immune macrophages cultured with medium 199 alone exerted some degree of cytotoxicity on the different target cell types tested. The macrophage product(s) retained cytotoxic activity storage at minus 20 degrees C, was stable when heated at 56 degrees C for 30 minutes, but was completely inactivated when exposed at 100 degrees C for 5 minutes. In the presence of 15 mug exogenous lysozyme/ml, the cytotoxic activity of the macrophage product(s) was significantly enhanced.

Animals↗
PubMed1975

Immunity to Toxoplasma gondii induced in vitro in non-immune mouse macrophages with specifically immune lymphocytes.

Male and female CBA mice were used to study in vitro the mechanisms involved in the development and expression of cellular immunity to toxoplasma infection. The lag phase preceding toxoplasma division was delayed in nonimmune macrophages obtained from peritoneal cavities stimulated with thioglycollate. Specific anti-toxoplasma activity was conferred on nonimmune macrophages incubated with toxoplasma-immune spleen lymphocytes and soluble toxoplasma antigen. Treatment of immune spleen cell populations with anti-theta serum plus complement abolished completely their activity of conferring anti-toxoplasma activity on nonimmune macrophages, demonstrating that the essential cells were T lymphocytes. The mediator(s) responsible for the acquisition of immunity to toxoplasma in the nonimmune macrophages were soluble. Heat-inactivated, toxoplasm-immune macrophages of fibroblasts. The findings are related to previous investigations of induced immunity in animals and man.

Animals↗
PubMed1974

In vitro antilisterial activity of soluble product(s) released from Listeria-immune murine peritoneal macrophages.

The importance of macrophages as effector cells in cellular reactions of immunity and hypersensitivity is well established (8). Macrophages activated as a result of specific immunological events exhibit increased microbicidal activity not only for the primary organism used for immunization purposes but also against unrelated intracellular pathogens (7). It is believed that the acquisition of this bactericidal or bacteriostatic activity is conferred on macrophages by materials released during the interaction of specifically immune lymphocytes with the antigen (Fowles et al., 1973; Godal et al., 1971; Jones and Youmans, 1973; Krahenbuhl and Remington, 1971; Mackaness, 1971; Patterson and Youmans, 1970). The antimicrobial activity in these studies refers to the intracellular inhibition and/or killing of the organisms; no attempts were made to assess the effect of activated macrophages on the extracellularly residing organisms. In an earlier study with the pathogenic yeastlike fungus Cryptococcus neoformans, we observed that freshly collected peritoneal macrophages from mice pretreated with a variety of nonspecific agents or from specifically immune mice possessed the capacity to exert anti-cryptococcal effect both on intracellular yeasts as well as those present in the extracellular milieu (Sethi et al., 1971; Sethi and Pelster, in press). Our results suggest that soluble product(s) released from mouse macrophages immune to Listeria monocytogenes can exert antilisterial activity under in vitro conditions.

Animals↗
PubMed1973

Neuraminidase induced loss in the transplantability of murine leukaemia L 1210, induction of immunoprotection and the transfer of induced immunity to normal DBA-2 mice by serum and peritoneal cells.

Leukaemia L 1210 cells preincubated in vitro with neuraminidase preparations derived either from Vibrio cholerae (VCN) or Clostridium perfringens (CPN) lost their i.p. transplantability for normal DBA/2 mice. This loss of transplantability could not be observed when the enzyme treated cells were implanted in mice whose immune status was suppressed by prior cyclophosphamide treatment. Mice receiving i.p. implants of enzyme treated leukaemia cells developed immunity to subsequent i.p. challenge with untreated L 1210 cells but not to a challenge with Ehrlich ascites tumour cells. The magnitude of immune response evoked by L 1210 cells preincubated with 250 u/ml of VCN or 35 μg/ml of CPN for 60 minutes was of relatively low level when compared with the immunity induced by leukaemia cells preincubated with 50 u/ml of VCN or 15 μg/ml of CPN for 30 or 60 minutes. Evidence is presented to show that the induced immunity can be transferred passively with the serum and with the peritoneal cells from the mice implanted with VCN treated L 1210 cells to normal DBA/2 mice. The significance of the neuraminidase induced increase in the immunogenicity of treated tumour cells is discussed.

Animals↗