Composition of the membranes isolated from several gram-positive bacteria

Saltón, M. R. J.; Freer, John H.

doi:10.1016/0304-4165(65)90197-2

Cited by 131 publications

(46 citation statements)

References 20 publications

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“…Examination of the products in the ultracentrifuge in both our studies (Salton and Netschey, 1965) and those of Razin et al (1965) suggested a surprising degree of apparent homogeneity, with components possessing sedimentation coefficients of about 2-3S. Although there is some doubt as to what the physicochemical behavior of the dissociated products means in terms of the size of lipid-protein associations in the native cell membrane (Engelman, Terry, and Morowitz, 1967;Salton, 1967 b), at least these studies have established that surface-active agents break down the membranes into relatively small lipid-protein-detergent aggregates.…”

Section: Time (Min)mentioning

confidence: 73%

“…Of immediate relevance to the lytic activity of surface-active compounds are the observations on the dissociation of isolated membranes from Grampositive bacteria (Salton and Netschey, 1965), envelopes (or "walls") from Gram-negative organisms (Shafa and Salton, 1960), and the membranes from Mycoplasma species (Razin et al, 1965). The disaggregation of the mem- …”

Section: Concentration Of Ctab (G/ml) In Supernatantmentioning

confidence: 99%

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Lytic Agents, Cell Permeability, and Monolayer Penetrability

Saltón

1968

The Journal of General Physiology

143

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Cell lysis induced by lytic agents is the terminal phase of a series of events leading to membrane disorganization and breadkdown with the release of cellular macromolecules. Permeability changes following exposure to lytic systems may range from selective effects on ion fluxes to gross membrane damage and cell leakage. Lysis can be conceived as an interfacial phenomenon, and the action of surface-active agents on erythrocytes has provided a model in which to investigate relationships between hemolysis and chemical structure, ionic charge, surface tension lowering, and ability to penetrate monolayers of membrane lipid components. Evidence suggests that lysis follows the attainment of surface pressures exceeding a "critical collapse" level and could involve membrane cholesterol or phospholipid. Similarities of chemical composition of membranes from various cell types could account for lytic responses observed on interaction with surface-active agents. Cell membranes usually contain about 20-30 % lipid and 50-75 % protein. One or two major phospholipids are present in all cell membranes, but sterols are not detectable in bacterial membranes other than those of the Mycoplasma group. The rigid cell wall in bacteria has an important bearing on their response to treatment with lytic agents. Removal of the wall renders the protoplast membrane sensitive to rapid lysis with surfactants. Isolated membranes of erythrocytes and bacteria are rapidly dissociated by surface-active agents. Products of dissociation of bacterial membranes have uniform behavior in the ultracentrifuge (sedimentation coefficients 2-3S). Dissociation of membrane proteins from lipids and the isolation and characterization of these proteins will provide a basis for investigating the specificity of interaction of lytic agents with biomembranes.The lysis or clearing of cell suspensions by lytic agents and lytic systems is the terminal phase of what has long been regarded as an interfacial phenomenon and has been the subject of intensive investigations for many decades. Much valuable information about the nature of cell surfaces had been deduced from these studies, at a time when the cellular membranes and walls were not amenable to the techniques of isolation now commonly employed. With the tremendous growth of our knowledge of the chemistry and structural organization of cell surfaces during the past 10 years, we are in a position to 227 s

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Section: Time (Min)mentioning

confidence: 73%

Section: Concentration Of Ctab (G/ml) In Supernatantmentioning

confidence: 99%

Lytic Agents, Cell Permeability, and Monolayer Penetrability

Saltón

1968

The Journal of General Physiology

143

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“…Before estimating the protein and RNA contents of membrane preparations, the membranes were suspended (4 mg./ml.) in deionized water and dispersed by ultrasonic disintegration (Salton & Freer, 1965). Protein was estimated by the method of Itzhaki & Gill (I964), except that the mixtures of membranes and reagents were centrifuged at about 5000 g for IO rain.…”

Section: Adsorption Of Phage (A) By Viable Streptococci Cultures Ofmentioning

confidence: 99%

The Adsorption of Phage to Group N Streptococci. The Specificity of Adsorption and the Location of Phage Receptor Substances in Cell-wall and Plasma-membrane Fractions

Oram

Reiter

1968

Journal of General Virology

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SUMMARYThe specificities of adsorption and multiplication of phages attacking some strains of lactic streptococci (serological group N) were investigated. At multiplicities of infection (m.o.i.) of o. I to I p.f.u./coccus, the specificity of adsorption was similar to that of multiplication, but some strains also adsorbed one or more h¢terotogous phages. At m.o.i. ~ IOO both homologous and heterologous strains of streptococci were lysed from without. The specificity of adsorption to cell walls was the same as to whole cocci and, with the exception of 2 phages, was irreversible at 3o °. Three types of phage receptors, with different specificities, were recognized in the cell wall. Extraction of streptococci with lipid-solvents did not affect the adsorption of those phages which were irreversibly adsorbed to cell walls but reduced the adsorption of other phages. The plasma membrane of Streptococcus lactis strain ML 3, but not the cell wall, inactivated phage ml 3 but not heterologous phages in the presence of electrolytes. The plasma membrane of a phage-resistant mutant of this strain did not inactivate phage although it was similar in chemical composition to that of the parent strain.

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“…Autolytic enzymes are suitable for preparing spheroplasts and protoplasts (Mohan et al, 1965; Joseph & Shockman, 1974) and for isolating bacterial membranes (Salton & Freer, 1965). Autolysis under controlled conditions is also an effective and gentle method for disintegration of cells to extract cell products (Linder, 19746; Davis & Salton, 1975).…”

Section: Introductionmentioning

confidence: 99%

Autolysis in Strains of Viridans Streptococci

Sund

Linder

1976

Journal of General Microbiology

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S U M M A R YSeven strains of viridans streptococci of the species Streptococcus sanguis, S. mutans and S. mitis were investigated for autolysis. The effect of pH, salt concentration and temperature on the autolytic process was studied in Na,HPO,/ NaH,PO, buffer. Whole cells and walls of all strains autolysed most rapidly at pH values above 7. Autolysis of whole cells of S. sanguis and one strain of S. mitis (ATCCI5909) was maximal in 0.05 to 0-2 M buffer, while the two S. mutans strains and S. mitis ATCCI5912 showed maximal autolysis in 0.5 and 1.0 M buffers.Cultures harvested in the stationary phase of growth possessed only slightly decreased autolytic activity compared with those from the exponential phase. Whole cells autolysed more rapidly at 37 "C than at 45 "C and 10 "C. Autolysis of isolated walls of three strains of S. mitis (ATCC903, A T C C I~~O~ and ATCCI5912) was maximal at pH 7.0 and 7.5 and in 1.0 M buffers. Streptococcus mitis A T C C I~~O~ also showed maximal lysis in 0.01 M and 0.5 M buffers. An endopeptidase action of the autolytic system of S. mitis ATCCI5912 was indicated by the progressive release of soluble amino groups during autolysis of the walls. No release of reducing groups was observed. Several free amino acids were released during autolysis of these walls, alanine, lysine and glutamic acid being in greatest quantity.

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Composition of the membranes isolated from several gram-positive bacteria

Cited by 131 publications

References 20 publications

Lytic Agents, Cell Permeability, and Monolayer Penetrability

Lytic Agents, Cell Permeability, and Monolayer Penetrability

The Adsorption of Phage to Group N Streptococci. The Specificity of Adsorption and the Location of Phage Receptor Substances in Cell-wall and Plasma-membrane Fractions

Autolysis in Strains of Viridans Streptococci

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