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D J RALSTON

Publications and source records attributed to D J RALSTON.

16 recordsLinked to original sources
PubMed1964

CELL-WALL LYSINS OF STAPHYLOCOCCUS AUREUS STRAINS INDUCED BY SPECIFIC TYPING PHAGES.

Ralston, Doris J. (University of California, Berkeley), and Mary McIvor. Cell-wall lysins of Staphylococcus aureus strains induced by specific typing phages. J. Bacteriol. 88:667-675. 1964.-At least 12 different phages induced the formation of soluble lysins (separable from the phages by ultracentrifugation). The lysins caused rapid clearing of heat-killed cells of all strains of Staphylococcus aureus tested, irrespective of the capacity of the phage to form plaques on living cells of the strain. The uninfected cells of the 12 strains contained a second lysin, an autolysin, released upon cellular autolysis. The autolysin preparations differed from the phage-induced lysins, in that they exhibited relatively high activity for lysing Micrococcus lysodeikticus and low activity for strain S. aureus K(1N), and were each specifically inhibited by antiserum prepared against purified autolysin from strain K(1). A third kind of lysin, virolysin, induced by polyvalent phage K, was differentiated from the lysins of the specific phages on the basis of its antigenic specificity and lack of action on M. lysodeikticus. All three kinds of lysins digested the mucopeptide portion of staphylococcal cell walls. No evidence was found that any of these lysins possessed specific host ranges which could be correlated with the lytic host range of the inducing phage.

Animals↗
PubMed1964

LYSIS-FROM-WITHOUT OF STAPHYLOCOCCUS AUREUS STRAINS BY COMBINATIONS OF SPECIFIC PHAGES AND PHAGE-INDUCED LYTIC ENZYMES.

Ralston, Doris J. (University of California, Berkeley) and Mary McIvor. Lysis-from-without of Staphylococcus aureus strains by combinations of specific phages and phage-induced lytic enzymes. J. Bacteriol. 88:676-681. 1964-Several typing phages, adsorbed in sufficient concentrations to their homologous propagating strains, altered the cell surface so as to render the cells sensitive to rapid and synergistic lysis by extra-cellular additions of wall lysins. Lysis was effected both by lysins induced by the individual phages and by phage K(1) virolysin. Phage K(1) also rendered cells sensitive to the lysins of the typing phages. With the exception of lysins from PS 53, 70, and 77, none of the lysins nor purified phages tested separately caused significant lysis of living cells. Lysis-from-without in Staphylococcus aureus appears to be a stepwise process: sensitization by phage followed by digestion of the wall by lysin.

Bacteriolysis↗
PubMed1963

STAPHYLOCOCCAL SENSITIZATION: SPECIFIC BIOLOGICAL EFFECTS OF PHAGE K ON THE BACTERIAL CELL WALL IN LYSIS-FROM-WITHOUT.

Ralston, Doris J. (University of California, Berkeley). Staphylococcal sensitization: specific biological effects of phage K on the bacterial cell wall in lysis-from-without. J. Bacteriol. 85:1185-1193. 1963.-Phage K, shown previously to sensitize staphylococcal-wall mucopeptide to the action of a phage-induced enzyme, virolysin, was found to act in a specific manner in that its sensitizing effects were restricted to chemical linkages affected by three staphylococcal lysins. These caused an immediate lysis, whereas egg-white lysozyme, which could also digest the wall mucopeptide, exerted variable effects, even when in the absence of phage it produced some lysis. Evidence was presented that the K(1) normal cell autolysin and the K phage virolysin could act synergistically with lysozyme on phage-sensitized cells, and that any effects observed with lysozyme were due to the simultaneous presence of trace amounts of these staphylococcal lysins. None of a series of lysozymelike agents from sea urchins, marine sepunculids, and from rabbit peritoneal histiocytes caused accelerated lysis of phage-sensitized cells, although like lysozyme they showed a slow lysis of phage-free living cells. Other enzymes which did not reduce the turbidity of sensitized cells included agents specific for intracellular components (proteins, lipids, nucleic acids), and enzymes, as decarboxylase, alkaline phosphatase, d-amino oxidase, and hyaluronidase. These results suggested that the main effects of the phage in sensitization were limited to areas of the cell wall involved in protection against the action of the staphylococcal lysins.

Animals↗
PubMed1963

INHIBITORY ACTION OF PHAGE K ON STAPHYLOCOCCAL DEHYDROGENASES. I. EFFECT ON VARIOUS STRAINS OF STAPHYLOCOCCUS AUREUS, INCLUDING MEMBERS OF THE PHAGE-TYPING SERIES.

Ralston, D. J. (University of California, Berkeley) and B. S. Baer. Inhibitory action of phage K on staphylococcal dehydrogenases. I. Effect on various strains of Staphylococcus aureus, including members of the phage-typing series. J. Bacteriol. 86:666-672. 1963.-The polyvalent phage K was found to depress the dehydrogenase activities of a large number of Staphylococcus aureus strains, as measured by the reduction of triphenyl tetrazolium chloride to the insoluble red formazan. The inhibition occurred immediately after the absorption of a multiplicity of phage particles, and was independent of the infectibility of the strains and of the killing ability of the phage. It appeared to be closely associated with the phenomenon of sensitization-a change in the cell surface which increased the susceptibility of the wall to digestion by soluble staphylococcal lysins and simultaneously abolished the capacity to synthesize phage. The inhibitory effect occurred both in nutrient media and in a nongrowth glucose - phosphate buffer supplemented with cysteine.

Bacteriophage Typing↗
PubMed1963

INHIBITORY ACTION OF PHAGE K ON STAPHYLOCOCCAL DEHYDROGENASES. II. ITS POSSIBLE RELATIONSHIP TO SENSITIZATION AND CELL LYSIS.

Ralston, D. J. (University of California, Berkeley) and M. D. Perry. Inhibitory action of phage K on staphylococcal dehydrogenases. II. Its possible relationship to sensitization and cell lysis. J. Bacteriol. 86:740-748. 1963.-By measuring the reduction of the dye triphenyl tetrazolium chloride to the insoluble red formazan, an analysis was made of the inhibition by phage K of the dehydrogenase capacity of populations of Staphylococcus aureus K(1), to determine to what extent this might be associated with the ability of phage K to sensitize the cells-a reaction characterized by the conversion of the cell wall to susceptibility to lysis by the staphylococcal enzyme, virolysin. Increasing multiplicities of phage progressively increased the fractions of sensitized cells and also caused increasing inhibition of the dehydrogenase activity of the populations. The dehydrogenase activities of the sensitized fractions were compared with those of the nonsensitized fractions. Over a wide range of phage-bacterium ratios, the dehydrogenase activities of the sensitized fractions were found to be lower than those of the nonsensitized fractions. Microscopically, this was reflected by the appearance of large numbers of cells with a reduced amount of visible formazan granules. When lysin was added to the phage-treated cells, lysis occurred mainly from cell fractions which possessed little or no tetrazolium-reducing capacity. The data indicated that sensitization by phage was accompanied by a marked decrease in cellular dehydrogenase activity but was not associated with a complete inhibition of these enzymes. A comparison was made between the dehydrogenases of phage-sensitized cells and cells found to be "spontaneously" sensitive to virolysin, i.e., lysed by the enzyme without any prior exposure to phage. Like phage-sensitized cells, the spontaneously sensitized staphylococci possessed low dehydrogenase activity and lacked the capacity to support phage synthesis. In tests of a given cell preparation, the dehydrogenase levels of the phage-sensitized fractions were found to be close to, or even lower than, the level of the spontaneously sensitized fraction, suggesting that in S. aureus K(1) the sensitized state is associated in some manner with a reduction of the dehydrogenase activity to a critical level. There is as yet no evidence for any direct causal relationship between sensitization and dehydrogenase inhibition.

Bacteriophages↗
PubMed1961

Lysis of brucellae by the combined action of glycine and a lysozyme-like agent from rabbit monocytes.

Ralston, Doris J. (University of California, Berkeley), B. S. Baer, and S. S. Elberg. Lysis of brucellae by the combined action of glycine and a lysozyme-like agent from rabbit monocytes. J. Bacteriol. 82:342-353. 1961.-An acid-extractable lytic material was obtained from rabbit monocytes. It acts on a substrate in the walls of brucellae and has properties similar to egg-white lysozyme. Brucella melitensis strain Rev Is is completely resistant to this agent and also to crystalline lysozyme, but when the cells are exposed to sufficient amounts of glycine, the surface is rendered susceptible to these lytic agents. Rough type Rev Is cells are more susceptible than smooth, and the virulent B. melitensis strain 6015 is most resistant.

Animals↗
PubMed1957

Lysis from without of S. aureus K1 by the combined action of phage and virolysin.

LYSIS FROM WITHOUT (LFW) OCCURS IN TWO STEPS: (1) sensitization of cells by phage, which renders the cells susceptible to (2) destruction of an essential cell structure by an extracellular lytic enzyme. Virolysin, from phage-infected cells, was used in these studies. Normal cell autolysin is also effective. Evidence is presented that: 1. Neither phage nor lysin alone causes LFW. 2. Sensitization requires phage adsorption. 3. It can be caused by non-infectious particles. This establishes a new biological activity of the particle. 4. Heat, U.V., detergents, penicillin, and other damaging agents also sensitize cells. 5. Sensitization involves a non-lethal, reversible reaction. 6. Sensitization by phage prevents virus synthesis. Following adsorption, a cell can undergo sensitization or infection but not simultaneously. When only a few particles are adsorbed, infection can occur; when sufficient particles are adsorbed, sensitization takes place. 7. Quantitative aspects of LFW are described. Lysis proceeds logarithmically. The lysis end-point depends upon the phage concentration but is independent of the enzyme concentration.

Bacteriophages↗
PubMed1957

Staphylococcal virolysin, a phage-induced lysin; its differentiation from the autolysis of normal cells.

Virolysin is a lysin which appears in Staphylococcus aureus K(1) cells infected with phage P(14); together with phage, virolysin is released from phage-infected cells at the time of lysis. Autolysin is a lysin formed by uninfected cells of the K(1) strain; autolysin is released from uninfected cells by autolysis. They show the following similarities: Both agents act within the genus Micrococcus. They lyse cells only after the cell has been subjected to a damaging or "sensitizing" treatment, such as heat, bacteriophage, acetone, or ultraviolet irradiation. The course of lysis of heated cells by both lysins has been found to proceed in a similar manner. A constant percentage of cells is lysed, independent of the concentration of lysin; the residual cells remain resistant to either lysin. Lysis proceeds logarithmically with time, and the velocity constants K are proportional to the lysin concentration. K increases with increasing temperature. Both lysins are unaffected by antiserum to the phage. They are inhibited alike by a number of chemicals, including known enzyme inhibitors. Both agents are destroyed by proteolytic enzymes and are precipitated by 40 per cent saturation with (NH(4))(2)SO(4). Both lysins are very thermolabile. The two lysins differ with respect to their pH optimum, antigenic relationship and specificity for Micrococcus lysodeikticus. These results suggest that (1) both lysins have many properties associated with enzymes, (2) the lysis of heated cells, which they produce, has some of the characteristics of a chemical reaction, (3) the lysin from the phage-infected cell is clearly different from the lysin of the uninfected cell.

Autolysis↗