Oxidation of macrophage membrane cholesterol by intracellular Rhodococcus equi.

Phagocytic uptake by cultured mouse macrophages (PD388D1) of a virulent strain (ATCC 33701) of Rhodococcus equi producing substantial cholesterol oxidase was accompanied by intracellular survival of the bacteria, and enzymatic oxidation of macrophage membrane cholesterol. A non-virulent strain (4219) lacking cholesterol oxidase was largely eliminated from the macrophages and did not bring about oxidation of membrane cholesterol. When R.

Some aspects of the history of membrane-damaging toxins.

In this review the following topics are considered: (a) the character of biomedical research and how it has changed during the last six decades; (b) the early history of membrane-damaging toxins; (c) comparative toxinology as illustrated by similarity of the toxins of the brown recluse spider and the bacterial agent of peudotuberculosis, and by similarity of a toxin of a sea anemone and the thiol-activated membrane-damaging agents of bacteria; (d) examples of the diversity of membrane-damaging toxins; (e) cooperative or synergistic lytic systems; and (f) the outlook for the future.

Characterization and amino acid sequences of two lethal peptides isolated from venom of Wagler's pit viper, Trimeresurus wagleri.

Two lethal toxins were isolated from Trimeresurus wagleri venom by fast protein liquid chromatography (molecular sieve) and high performance liquid chromatography (reverse phase). The toxins (termed peptide I and II) had mol. wt of 2504 and 2530, respectively, pIs of 9.

Cytotoxicity of cholesterol oxidase to cells of hypercholesterolemic guinea pigs.

1. A high cholesterol diet caused guinea pig erythrocytes to become sensitive to lysis by cholesterol oxidase (CO), a protein not hemolytic to normal cells. 2.

Kinetics of hemolysis induced by a toxin from Bacillus thuringiensis israelensis.

The kinetics of hemolysis resulting from the action on rabbit erythrocytes of a highly purified cytolytic toxin (26,000 mol. wt) isolated from a spore-crystal mixture of Bacillus thuringiensis israelensis was studied. Course of hemolysis, as determined by release of hemoglobin, yielded sigmoid curves whose maximum slopes were taken as a measure of the rate of lysis.

Isolation of a hemolysin from a spore-crystal mixture of Bacillus thuringiensis israelensis (serotype H-14).

A hemolytic toxin from Bacillus thuringiensis israelensis was obtained by alkaline extraction and fast protein liquid chromatography (chromatofocusing followed by gel filtration). The toxin displayed a pI of 4.6-4.

Phospholipase D activity of Vibrio damsela cytolysin and its interaction with sheep erythrocytes.

Exposure of sheep erythrocytes to sublytic amounts of Vibrio damsela cytolysin markedly reduced their membrane sphingomyelin content and their sensitivity to lysis by the sphingomyelin-dependent cytolysins staphylococcal sphingomyelinase C (beta-toxin) and helianthin. The toxin was found to be a phospholipase D active against sphingomyelin.

Toxicity of enzymically-oxidized low-density lipoprotein.

Intravenous injection of cholesterol oxidase into hyperlipidemic rabbits in which aortic atheromatous lesions have been induced by dietary means is lethal within hours, whereas injection of the same enzyme into normal rabbits has no visible adverse effect. The lethal effect of the enzyme is explicable by the finding that injection of cholesterol-oxidase treated low-density lipoprotein kills normal rabbits, in contrast to untreated low-density lipoprotein which does not. Enzymically oxidized low-density lipoprotein was also found to be cytotoxic for two human cell lines and for cultured bovine aortic endothelial cells.

Isolation and characterization of a phospholipase B from venom of Collett's snake, Pseudechis colletti.

Phospholipase B in the venom of the Australian elapid snake, Pseudechis colletti, was purified to near homogeneity. By means of gel filtration it had an Mr of about 35,000, and by SDS-polyacrylamide gel electrophoresis an Mr of about 16,500. These presumably are dimeric and monomeric forms of the enzyme.

Some properties of flammutoxin from the edible mushroom Flammulina velutipes.

A cytolytic toxin from the basidiocarps of the edible mushroom Flammulina velutipes was purified to homogeneity. The lysin, flammutoxin, is a single polypeptide chain of Mr 32,000 and pK about 5.4.

Copurification of Leptospira interrogans serovar pomona hemolysin and sphingomyelinase C.

The hemolytic and sphingomyelinase C activities of supernatants of cultures of Leptospira interrogans serovar pomona tended to copurify when isoelectric fractionation was carried out. Both activities focused primarily at pH 8.1.

Interactions between membranes and cytolytic peptides.

The physico-chemical and biological properties of cytolytic peptides derived from diverse living entities have been discussed. The principal sources of these agents are bacteria, higher fungi, cnidarians (coelenterates) and the venoms of snakes, insects and other arthropods. Attention has been directed to instances in which cytolytic peptides obtained from phylogenetically remote as well as from related sources show similarities in nature and/or mode of action (congeneric lysins).

Isoelectric analysis of some Australian elapid snake venoms with special reference to phospholipase B and hemolysis.

Venoms of the Australian elapid snakes Austrelaps superbus and Pseudechis colletti were analyzed in an electrofocusing column. A. superbus venom, little studied in the past, was found to have a mouse i.

Comparative toxinology of Loxosceles reclusa and Corynebacterium pseudotuberculosis.

In contrast to other kinds of phospholipases, phospholipases D that are toxic for humans and animals are not commonly encountered as constituents of venoms or as products of pathogenic microorganisms. Toxic phospholipases D are present, however, in the venom of the brown recluse spider (Loxosceles reclusa) and in supernatants or filtrates of cultures of Corynebacterium pseudotuberculosis. Although the two enzyme toxins are derived from phylogenetically disparate entities, they are similar in molecular weight, charge, substrate specificity, and in several biological activities.

Properties of a cytolytic toxin from the sea anemone, Stoichactis kenti.

A cytolytic toxin (kentin) from the Indo-Pacific sea anemone, Stoichactis kenti, was purified to near homogeneity. The toxin is a basic polypeptide of molecular weight approximately 18,000. It broadly resembles cytotoxins from Stoichactis helianthus (helianthin), as well as similar toxins from a number of other anemones, namely Condylactis, Epiactis, Actinia, Pseudactinia, Tealia, Anthopleura, Radianthus and Gyrostoma.

Cross-reactions of polysaccharides of fungi, molds, and yeasts in anti-pneumococcal and other antisera.

Cross-reactions of a number of glycans and polysaccharides isolated from fungi, molds, and yeasts in anti-pneumococcal and other antisera are tabulated and discussed insofar as possible with relation to the chemical structures of the cross-precipitating substances and the polysaccharidic antigens giving rise to the reactive antibodies. For example, the slime of Physarum polycephalum precipitated antisera to pneumococcal type 4 and Klebsiella type K1. The polysaccharides of type 4 and K1 contain pyruvic acid in acetal linkage on hydroxyls 2 and 3 of sugars.

Action of bacterial cytotoxins on normal mammalian cells and cells with altered membrane lipid composition.

Cytotoxic proteins produced by a number of bacteria, as well as one from a marine invertebrate, were tested for their ability to disrupt the permeability barrier of mammalian cells. Agents were tested individually and in combination shown to have synergistic disruptive actions on erythrocytes. Toxins included the lipid-hydrolyzing enzymes sphingomyelinases C and D and cholesterol oxidase, as well as the non-enzymatic agents, helianthus toxin, streptolysin O and saponin.

Purification and properties of a toxin from the South African sea anemone, Pseudactinia varia.

A comparison was made of the hemolytic potency of aqueous extracts prepared from five species of intertidal sea anemones from the coast of South Africa. The active agent in an extract of Pseudactinia varia was purified by ammonium sulfate precipitation, gel permeation chromatography and isoelectric focusing. The hemolytic toxin, termed variolysin, is a protein having a molecular weight of 19,500 and an isoelectric pH of 9.

Annular structures in erythrocyte membranes of various animal species as revealed by electron microscopy.

Electron microscopic examination of negatively stained erythrocyte membranes revealed the presence of annular structures having an overall diameter of 33 nm and a ring-thickness of 9 nm. Each annular structure appeared to be composed of eleven globular subunits. The structures were most conspicuous in human erythrocyte membranes which showed, on the average, 160 per membrane.

Mechanism of hemolysis by Renalin, a CAMP-like protein from Corynebacterium renale.

Synergistic hemolysis of sheep erythrocytes caused by Staphylococcus aureus and Corynebacterium renale resulted from the combined action of extracellular staphylococcal sphingomyelinase C and a newly described extracellular agent of C. renale (renalin). The affinity of renalin for ceramide was considered to play a key role in causing hemolysis in erythrocytes in which ceramide had been generated through the action of sphingomyelinase C.