The Effect of Pyruvate and Acetate on the Rate of Decrease in Optical Density of Suspensions of Pseudomonas aeruginosa in Sodium, Potassium or Sodium-Potassium Phosphate Buffers

Bernheim, Frederick

doi:10.1099/00221287-34-2-327

Cited by 5 publications

(2 citation statements)

References 4 publications

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“…FIG. 4. Optical density increase in a suspension of Rickettsia mooseri as a function ofsucrose osmolality, and demonstration of necessity to use Ficoll refractive Index correction values to detect optical density (OD) rise.…”

Section: Refractive Indexmentioning

confidence: 99%

Permeability Properties of Rickettsia mooseri

1967

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The passive permeability properties of Rickettsia mooseri to both inorganic and organic solutes have been examined. Visual observations by phase-contrast microscopy of rickettsiae in macerated yolk sacs taken directly from heavily infected eggs revealed plasmolysis with hypertonic NaCl and KCl as well as with sucrose solutions. In contrast, similar visual studies of rickettsiae which had been subjected to freezing or to a purification process, or both, were plasmolyzed by hypertonic sucrose but not by hypertonic NaCl and KC1. These primary observations were extended to a variety of solutes and were placed on a quantitative basis by use of optical density and radioisotope dilution methods. Intracellular Na+ and K+ concentrations in processed rickettsiae, measured by flame photometry, closely paralleled the concentration of these ions in the suspending medium. It was concluded that R. mooseri appears to possess an osmotically active, functional, and structural membrane distinct from the cell wall, located at the surface of a structure analogous to the bacterial protoplast. In the intact organism, this membrane is passively impermeable to sucrose, NaCl, and KCl. However, altered permeability properties, especially to inorganic electrolytes, may be expected in rickettsiae which have been stored in the frozen state and subjected to a lengthy purification process. The basis for the apparent obligate nature of intracellular parasitism among pathogenic rickettsiae remains unknown. With their relatively

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Section: Refractive Indexmentioning

confidence: 99%

Permeability Properties of Rickettsia mooseri

1967

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“…The swelling is the result of the influx of ions because isosmolar sucrose, to which the cells are impermeable, causes an equivalent shrinkage but little or no subsequent swelling occurs unless ions are added (1). The rate of swelling is the result of a metabolically aided diffusion of ions (2,7) both into and out of the cells. As shown below, cells incubated under semianaerobic conditions swell to a greater extent than those fully oxygenated.…”

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confidence: 98%

A comparison between the effects of a surfactant (chenodeoxycholamine) and freezing and thawing on some properties of the membrane of Pseudomonas aeruginosa

Bernheim¹

1968

Can. J. Microbiol.

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Chenodeoxycholamine, a bile acid conjugated with a quaternary amine, increases the rate of swelling of cells of a strain of Pseudoinonas aer~ginosa suspended in 0.05 M Na-K phosphate buffer, pH 7.7. It also inhibits benzoate oxidase induction but only when the concentration of the buffer is increased. The rate of swelling in normal and treated cells apparently depends on the rate of influx of ions. Ion efflux may also occur in the presence of an oxidizable substrate. Freezing and thawing has effects similar to those of the drug. Low concentrations of ninhydrin or mercuric chloride inhibit the induction of benzoate oxidase. The inhibition is markedly decreased in drug-treated and frozen and thawed cells.

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Preparation and characterization of mouse intestinal phospholipase

Ottolenghi

1973

Lipids

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Phospholipase has been prepared in a stable, partially purified form from the small intestine of mice infected with the tapewormHymenolepis nana. The enzyme(s) attacks diacylphosphatides with liberation of free fatty acids and a corresponding decrease in phospholipid phosphorus, without accumulation of lysophosphatides. The reactivity with various substrates is strongly influenced by their physical state, the presence of other lipids, proteins or detergents. The phospholipids of some biomembranes (mitochondria, microsomes, red cell ghosts) are readily hydrolyzed under customary reaction conditions. The ensuing biochemical, morphological and functional alterations have been documented. In contrast, the diacylphospholipids of the cell membrane (intact erythrocytes,Pseudomonas aerunginosa) are not accessible to phospholipase action unless some alteration of the integrity of the cell is induced by physical or chemical means (hemolysis, polymyxin). The enzyme is proposed as a tool for the investigation of biomembranes and as a model for the study of phospholipase activity.

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The Effect of Pyruvate and Acetate on the Rate of Decrease in Optical Density of Suspensions of Pseudomonas aeruginosa in Sodium, Potassium or Sodium-Potassium Phosphate Buffers

Cited by 5 publications

References 4 publications

Permeability Properties of Rickettsia mooseri

Permeability Properties of Rickettsia mooseri

A comparison between the effects of a surfactant (chenodeoxycholamine) and freezing and thawing on some properties of the membrane of Pseudomonas aeruginosa

Preparation and characterization of mouse intestinal phospholipase

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