pH‐dependent changes in density of plasma membranes of growing <i>Mycoplasma laidlawii</i> cells

Kahane, Itzhak; Разин, С.Ю.

doi:10.1016/0014-5793(70)80643-3

Cited by 16 publications

(3 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Calculated on this basis, lipids will constitute about 30% of the total dry weight of the membrane. This value and the values obtained for the density of the S. citri membranes (Table 1) are well within the range found for mycoplasma membranes (21,34). The isolated S. citri membranes were somewhat contaminated with nucleic acids (Table 1) in spite of their treatment with deoxyribonuclease.…”

Section: S Citri Membrane Bfsupporting

confidence: 85%

Isolation, Chemical Composition, and Ultrastructural Features of the Cell Membrane of the Mycoplasma-Like Organism Spiroplasma citri

et al. 1973

View full text Add to dashboard Cite

Thin sections of Spiroplasma citri, a mycoplasma-like organism isolated from citrus infected with "Stubborn" disease, showed the organisms to be limited by a single trilaminar plasma membrane. An additional outer layer could, however, be frequently seen in freeze-etched preparations of unwashed cells. The organisms were found to be extremely sensitive to lysis by osmotic shock. The cell membrane of S. citri isolated in this way resembled that of mycoplasmas in ultrastructure and gross chemical composition. The isolated membranes showed the characteristic trilaminar shape in section and the typical particle-studded fracture faces in freeze-etched preparations. Protein and lipid formed over 80% of the total dry weight of the membrane, which had a density of-1.180 g/cm3. Cholesterol constituted over 20% of the total membrane lipid. Phosphatidylglycerol, synthesized by the organisms, was the major phospholipid. Significant amounts of hexosamine (15 to 35 ,ug/mg of membrane protein) could be found in the membrane preparations. Our results support the thesis that S. citri does not possess a cell wall, either of the gram-positive or the gram-negative type, though it may be coated by some other type of an envelope or by a slime layer, at least temporarily.

show abstract

Section: S Citri Membrane Bfsupporting

confidence: 85%

Isolation, Chemical Composition, and Ultrastructural Features of the Cell Membrane of the Mycoplasma-Like Organism Spiroplasma citri

et al. 1973

View full text Add to dashboard Cite

show abstract

“…The finding that purified M. pulmonis membrane preparations consisted of two populations of membrane vesicles, based on density, has also been reported for A. laidlawii membrane preparation (8). The purity of membranes was shown by the absence of cytoplasmic contaminants (i.e., hexokinase and nucleic acids) and by density gradient analysis.…”

Section: Discussionsupporting

confidence: 53%

Isolation of Mycoplasma pulmonis membranes and identification of surface antigens

Horowitz¹,

Garrett²,

Davis³

et al. 1987

Infect Immun

View full text Add to dashboard Cite

Labeling of Mycoplasma pulmonis cells by iodination with the Bolton-Hunter reagent was shown to efficiently label membrane-associated proteins without significant loss of viability. Labeled proteins proven to be surface exposed by differential proteolytic digestion were analyzed by autoradiography of two-dimensional polyacrylamide gel electrophoresis (PAGE), and seven labeled major polypeptides were identified. To identify all the membrane-associated antigens, pure membranes were isolated by using the surface-labeled proteins as markers. Analysis of the isolated membranes by autoradiography of both sodium dodecyl sulfate-PAGE and the two-dimensional PAGE indicated that the labeled surface proteins were retained in the pure membranes; by immunoblotting with sera from naturally infected animals, these surface proteins were shown to be the predominant antigens recognized by the host during natural infection.

show abstract

“…In the case of A . laidlawii, the composition of its membrane varies with the culture conditions and the age of the culture, which is reflected in its protein-lipid ratio (Kahane and Razin 1970;Pisetsky and Terry 1972). In this communication a simple and accurate spectrophotometric method that directly deter-'Present address: Department of Biophysics.…”

mentioning

confidence: 99%

Rapid spectrophotometric determination of Acholeplasma laidlawii membranes

Dresdner¹

1978

Can. J. Microbiol.

View full text Add to dashboard Cite

The amount of Acholeplasma laidlawii membranes can be accurately, rapidly, and simply determined by spectrophotometric measurements after solubilization in 0.02 M SDS, 0.02 M Tris-HCl (pH 8.0). Extinction coefficients from the 260- to 300-nm-absorption region are adequate for quantitative membrane determination. The following values were found: E1%1cm,280 = 9.11 +/- 0.63, E1%,S1cm,280 = 8.52 +/- 0.40 (corrected for light scattering), E1%1cm,280--310 = 8.15 +/- 0.35. The last value is the most satisfactory for routine analysis. These coefficients are not affected by large differences in the carotene and flavin contents of the membranes or by spectral changes that occur when the membranes are exposed to light. The precision obtained with this method is comparable with that achieved in spectrophotometric determinations of proteins. As little as 6 microgram of membrane can be measured in 50-microliter samples.

show abstract

pH‐dependent changes in density of plasma membranes of growing Mycoplasma laidlawii cells

Cited by 16 publications

References 21 publications

Isolation, Chemical Composition, and Ultrastructural Features of the Cell Membrane of the Mycoplasma-Like Organism Spiroplasma citri

Isolation, Chemical Composition, and Ultrastructural Features of the Cell Membrane of the Mycoplasma-Like Organism Spiroplasma citri

Isolation of Mycoplasma pulmonis membranes and identification of surface antigens

Rapid spectrophotometric determination of Acholeplasma laidlawii membranes

Contact Info

Product

Resources

About