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At least 757 records · Page 42Linked to original sources
PubMed1965

POLYRIBOSOMES FROM ESCHERICHIA COLI: ENZYMATIC METHOD FOR ISOLATION.

Polyribosomes can be rapidly extracted from Escherichia coli by sequential passage of the cells through solutions of a chelating agent and lysozyme in a centrifugal field. Biosynthesis of protein in whole cells and in a cell-free system occurs almost exclusively in the polyribosomes.

Animals↗
PubMed1965

DEOXYRIBONUCLEIC ACID BASE COMPOSITION OF SOME MEMBERS OF THE SUBGENERA BETABACTERIUM AND STREPTOBACTERIUM.

The base composition of deoxyribonucleic acid (DNA) prepared from four Betabacterium strains and four Streptobacterium strains was determined. Per cent GC values (guanine + cytosine/total bases) of the DNA were evaluated from the "melting-temperatures" (Tm) of the nucleic acids. For the Betabacterium strains, these values ranged from 44 to 51.5% GC, and those for the Streptobacterium strains ranged from 43 to 47.5% GC. The taxonomic division into these two subgenera is not, therefore, supported by these findings.

Base Composition↗
PubMed1962

Formation of protoplasts from Streptococcus faecalis by lysozyme.

Bibb, William R. (University of North Carolina, Chapel Hill) and W. R. Straughn. Formation of protoplasts from Streptococcus faecalis by lysozyme. J. Bacteriol. 84:1094-1098. 1962.-Incubation of whole cells of Streptococcus faecalis F24 in the presence of the crystalline egg-white lysozyme and appropriate sucrose concentration resulted in the formation of discrete spherical structures. On dilution, these osmotically fragile structures lysed immediately. Methyl pentose determinations on isolated cell walls and protoplast membranes verified the presence of rhamnose in the cell walls and its essentially complete absence in protoplast membranes. Cell walls were rendered soluble by lysozyme. After lysozyme treatment of cell walls, 96% of the rhamnose present was not sedimented by centrifugation at 12,500 x g for 30 min. No cell-wall structures were recognized by phasecontrast or electron microscopy. After direct lysis of whole cells of S. faecalis F24 by lysozyme, protoplast membranes were isolated. It is concluded that, in the strain of group D streptococcus studied, lysozyme effectively removes the cell wall.

Anti-Infective Agents, Local↗
PubMed1963

Mechanism of protection of cells by spermine against lysozyme-induced lysis.

Grossowicz, Nathan (Hebrew University Hadassah Medical School, Jerusalem, Israel) and Miriam Ariel. Mechanism of protection of cells by spermine against lysozyme-induced lysis. J. Bacteriol. 85:293-300. 1963.-Spermine (1 to 5 x 10(-3)m) was found to prevent lysis of Micrococcus lysodeikticus cells by lysozyme. This protection is due to the rapid and efficient stabilization by spermine of the protoplasts formed by lysozyme, and not to interference with the enzymatic activity. This conclusion concerning the spermine effect is based on chemical and microscopic evidence: (i) the amount of hexosamine, released from lysozyme-treated cells, was equal to or even higher in the presence of spermine than in its absence; (ii) microscopic and electron microscopic pictures showed clearly that the spermine-protected structures resembled protoplasts. On the other hand, the "spermine protoplasts" showed a high stability against hypotonic conditions in comparison with "sucrose protoplasts." The spermine-protoplast complex was very stable and could not be destroyed by water and various agents (NaCl, KCl, MgCl(2), cadaverine, and putrescine). A number of bases such as histamine, d-histidine, and streptomycin exhibited an effect similar to that of spermine, while diamines like cadaverine, putrescine, basic amino acids (lysine, arginine, l-histidine), as well as cations like magnesium, were virtually inactive.

Bacteriolysis↗
PubMed1963

PREPARATION OF SPHEROPLASTS FROM VIBRIO COMMA.

Chatterjee, B. R. (Baylor University College of Medicine, Houston, Texas), and Robert P. Williams. Preparation of spheroplasts from Vibrio comma. J. Bacteriol. 85:838-841. 1963.-Spheroplasts were prepared from several strains of Vibrio comma by lysozyme treatment combined with freezing and thawing of the organisms. The optimal concentration of lysozyme was 50 mug/ml, although some spheroplasts formed at a concentration of 10 mug/ml. Higher concentrations (200 mug/ml) caused lysis of cells along with spheroplast formation. Treatment was carried out in broth cultures containing 15% sucrose, and if the osmotic tension was lowered the spheroplasts lysed. Some motile, spherical cells were present in every preparation. Addition of 3% glycine to broth cultures resulted in rapid transformation of the vibrios into large, spherical bodies. However, these were actively motile, and were not sensitive to a lower osmotic tension. Therefore, they could not be considered as spheroplasts.

Bacteriological Techniques↗
PubMed1963

CORRELATION OF SPECIATION WITH LYTIC RESPONSES OF THE ACHROMOBACTER.

Surdy, Theodore E. (Purdue University, Lafayette, Ind.) and S. E. Hartsell. Correlation of speciation with lytic responses of the Achromobacter. J. Bacteriol. 85:1011-1016. 1963.-Lysozymic lysis of six species of Achromobacter was investigated. Three of the six species were lysed with 33, 50, or 100 mug/ml of lysozyme; if higher concentrations of lysozyme were used, precipitation of cells occurred. "Insensitive" cells could be sensitized by the addition of potassium hydroxide, n-butanol, steapsin, or urea, as demonstrated by the subsequent addition of lysozyme. Not all species were sensitive to these agents in the same degree; hence, a spectrum was obtained after the use of the pretreating agents and lysozyme. Optimal clearing of suspensions was observed when cells were suspended in pH 6.6 physiological saline or 0.15 m phosphate buffer and incubated at 45 C. Heat treatment (75 C for 10 min) or freezing (-32 C) and thawing (room temp, 25 C) for one cycle did not increase the sensitivity of the cells to lysozyme. Injury to the cells was evident by the increased amount of lysis noted after pretreatment with potassium hydroxide. When cells were frozen and thawed for three cycles, four of the six species were sensitive to the action of lysozyme. Isolated cell walls elicited a similar lytic pattern to that of whole cells. Individuality of the lytic response of the species (from most sensitive to least sensitive-A. aquamarinus, A. butyri, A. viscosus, A. parvulus, A. guttatus, A. hartlebii) produced a separation scheme. Exhaustive tests proved it to be stable and reliable for these species. The organisms were identified, with the use of the separation scheme, by a person initially unfamiliar with the scheme or the culture.

Achromobacter↗
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↗