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PubMed1986

Inhibition of wall autolysis of staphylococci by sodium polyanethole sulfonate "liquoid".

Liquoid (polyanethole sulfonate) was neither capable of influencing the growth nor the viability of staphylococci. But liquoid induced a suppression of the activity of different autolytic wall systems of normally growing staphylococci, i.e., autolysins which participate in cross wall separation as well as autolysins which are responsible for cell wall turnover. Additionally, the lysostaphin-induced wall disintegration of staphylococci was inhibited by liquoid. However, no indication could be found for a direct inhibition of lytic wall enzymes by liquoid; rather an interaction of liquoid with the target structure for the autolytic wall enzymes, the cell wall itself, was postulated. On the basis of the experimental data with the teichoic acid- mutant S. aureus 52A5 the sites of wall teichoic acid were supposed to be an important target for the binding of liquoid to the staphylococcal cell wall.

Bacteriolysis↗
PubMed1976

Alterations in the cell wall of Spirillum serpens VHL early in its association with Bdellovibrio bacteriovorus 109D.

In both freeze-etched and critical-point dried preparations examined by transmission and scanning electron microscopy, respectively, the outer surfaces of the cells of Spirillum serpens VHL assume a wrinkled appearance 10-15 min after challenge by Bdellovibrion bacteriovorus 109D. This wrinkling effect is believed (on circumstantial evidence) to be caused by the bdellovibrio's disruption of the cell wall lipoprotein of the Spirillum. With the exception of those topological changes caused by wrinkling, the outer membrane of the Spirillum cell wall retains a normal appearance, as viewed in freeze-etched preparations, even after the Spirillum cell has been converted into a bdelloplast. Although the peptidoglycan layer of the Spirillum cell presumably is weakened somewhat by the invading Bdellovibrio, evidence obtained from freeze-fractured preparations of Spirillum bdelloplasts suggests that the peptidoglycan remains as a discrete cell wall layer, even though the Spirillum cell wall apparently has lost much of its rigidity. That the peptidoglycan backbone remains essentially intact, even after the Spirillum cell has been entered by the Bdellovibrio, is supported by the observation that the soluble amino sugar content of the culture medium, as determined by chemical analysis, does not rise even 5.0 h after the association of the Bdellovibrio with the Spirillum has begun.

Amino Sugars↗
PubMed1975

Energy metabolism of Bdellovibrio bacteriovorus. I. Energy production, ATP pool, energy charge.

Bdellovibrio bacteriovorus, strain Bd. 109 Sa, generates ATP mainly by oxidative phosphorylation during electron transport. During exponential growth the ATP pool is constant (9 mmoles/100 mugN) indicating that energy-producing and energy-consuming reactions are well balanced. The ratio of substrate respiration/endogenous respiration is approx. 2.5/1. Energy charge is constant both in endogenous and substrate respiration at values of 0.62 to 0.64. During endogenous respiration (starvation) the ATP pool oscillates at regular intervals. ATP over-production is started after the ATP pool has decreased to a minimum level of 6 nmoles/100 mug N. The alternating over- and under-production of ATP is interpreted as a special regulation which enables the organism to make economic use of its own cellular materials. Addition of substrate (glutamate) to starving cells does not influence the type of ATP pool oscillation as observed in endogenous respiration. The parasitic strain Bd. 109 Pa exhibits the same periodicity of ATP overproduction as does it saprophytic derivative, Bd. 109 Sa. Decrease of viability during starvation is paralleled by a decrease of the ATP pool.

Adenine Nucleotides↗
PubMed1977

Acidostability of speroplasts prepared from Thiobacillus thiooxidans.

Thiobacillus thiooxidans was acidostable even in the absence of its respiratory substrate, elementary sulfur. This suggests that the acidostability of the bacterium was enery-independent. The organism was subjected to osmotic shock with 0.75 M sucrose at 0 degrees C and then treated with snail intestinal juice in the presence of 0.3 M sucrose. The decrease in the optical density of the sample thus prepared on dilution with deionized water and electron microscopic observation of the sample showed that spheroplasts were formed from the bacterium by this procedure. Spheroplasts were able to respire sulfur and their respiratory activity was acidostable. Spheroplasts, when treated with Nagase, proteolytic enzyme, lost their acidostability, and some protein components disappeared from the membrane fraction. This suggests that the acidostability of the bacterium may be related to protein conponents of the membrane.

Acidithiobacillus thiooxidans↗
PubMed1975

Protoplasts of Trichoderma viride: formation and regeneration.

High yields of protoplasts from the 18-hr old mycelium of Trichoderma viride were obtained by using the lytic system, produced by Streptomyces venezuelae RA and Micromonospora chalcea grown on a synthetic medium containing laminarin and chitin, when 0.7 M MgSO4 or (NH4)2SO4 were used as osmotic stabilizers. Regeneration of these protoplasts occurred through the production of an abortive tube and direct germination of the protoplasts. Regeneration could also take place in the medium used to produce protoplasts, but the process was different in many details.

Bacteriolysis↗
PubMed1975

A study of complement components C3, C5, C6, C7, C8 and C9 in chronic membranoproliferative glomerulonephritis, systemic lupus erythematosus, poststreptococcal nephritis, idiopathic nephrotic syndrome and anaphylactoid purpura.

In a comparative study the hemolytic activity of C3, C5, C6, C7, C8, C9 and the C3 proactivator (C3PA) were measured in sera of 22 patients with chronic membrano-proliferative glomerulonephritis (CMPGN), 15 patients with idiopathic nephrotic syndrome, 10 patients with systemic lupus erythematosus, 7 patients with anaphylactoid purpura and 10 patients with acute poststreptococcal nephritis. In CMPGN, C3, C5, C6, C7 and C8 were low in the majority of the patients, whereas C9 and C3PA were depressed only in 21% and 11% of the patients, respectively. By contrast, C3PA and C8 showed striking depressions in the idiopathic nephrotic syndrome. In lupus erythematosus, all the C factors, including C3PA were found to be low with the exception of C9, which was normal in 80% of the patients studied. C3, C5, C6 and C7 were found to be depressed in acute glomerulonephritis; C8 and C9 titers were normal. In all patients studied with anaphylactoid purpura, CH50 and C3 titers were elevated markedly.

Adolescent↗
PubMed1975

Characterization of Rhodopseudomonas capsulata.

Thirty-three strains of Rhodopseudomonas capsulata have been studied in order to develop a more comprehensive characterization of the species. On the basis of morphological, nutritional, physiological and other properties, the characteristics of an "ideal biotype" have been defined, which can be used to distinguish Rps. capsulata from similar purple bacteria. In this connection, two properties of Rps. capsulata are of particular note: a) sensitivity to penicillin G is 10(3)-10(5) times greater than that shown by closely related species, and b) all strains examined are susceptible to lysis by one or more strains of host species-specific virulent bacteriophages. It appears that members of the species Rps. capsulata form a stringent taxonomic grouping.

Anaerobiosis↗
PubMed1976

Degeneration of the Gonococcus (in various media).

The ultrastructure of the gonococcus cultivated in different synthetic media and inoculated into the peritoneal cavity of the mouse makes it possible to distinguish the various degenerative morphological states of the microbe. A comparative study of phagocytosis and transformation of the gonococcus by leukocytes together with the changes observed in artificial media discloses a certain resemblance between the different stages of the progression towards L forms. Reversion to normal forms is only possible if gonococcal degeneration has not reached an extreme point and if the new medium compensates for the unfavourable conditions which produced L transformation.

Animals↗
PubMed1994

The antidote and autoregulatory functions of the F plasmid CcdA protein: a genetic and biochemical survey.

The ccd operon of the F plasmid contributes to the high stability of the episome by postsegregational killing of plasmid-free bacteria. It contains two genes, ccdA and ccdB, which are negatively autoregulated at the level of transcription, probably by a complex comprising the two gene products. Using the bacterial gyrA462 CcdB resistance mutation and a Pccd-lacZ transcriptional fusion, we have obtained evidence that the CcdB protein by itself has no regulatory activity or operator DNA-binding affinity and needs CcdA in order to effect transcriptional control. The ccd killing mechanism is based on the poison-antidote principle. The CcdB protein is cytotoxic, poisoning DNA-gyrase complexes, while CcdA antagonizes this activity. In order to define functional domains of the CcdA antidote involved in the anti-killer effect, autoregulation or both, we introduced several missense or amber mutations into the CcdA protein by directed mutagenesis. We report on missense CcdA proteins that have lost their autoregulatory properties but are still able to antagonize the lethal activity of CcdB. We show that the five carboxy-terminal amino acid residues of the antidote protein are not required for the antidote effect or for autoregulation. Several missense CcdA polypeptides were generated by suppression of nonsense codons. Two substitutions lead to CcdB-promoted killing: glutamine 33-->cysteine and glutamine 33-->phenylalanine.

Bacterial Proteins↗
PubMed1975

Interaction between Bdellovibrio bacteriovorus and the cytoplasmic membrane of Escherichia coli B.

Adsorption of Bdellovibrio bacteriovours (Bdv) on the surface of Escherichia coli is accompanied by a sharp decrease in the initial rate of entry of alpha-methylglucoside-C-14 and thiomethlgalactopyranoside-C-14 into the host cell. Interaction between the parasite and E. coli leads to the rapid departure of previously accumulated labeled glucosides and beta-galactosides from the bacteria. Meanwhile the ATPcontent in E. coli falls sharply. Adsorption Bdv E.coli spheroplasts was established as a fact. The possible mechanisms of interaction between Bvd and the host cell at the cytoplasmic membrane level are discussed.

Adenosine Triphosphate↗
PubMed1995

Bacteriolytic activities of the free-living soil amoebae, Acanthamoeba castellanii, Acanthamoeba polyphaga and Hartmannella vermiformis.

Bacteriolytic activities of axenically grown free-living soil amoebae Acanthamoeba castellanii, Acanthamoeba polyphaga and Hartmannella vermiformis towards various Gram-positive and Gram-negative bacteria were determined. A spectrophotometric assay revealed that the specific bacteriolytic activities of both Acanthamoeba species were higher as those of the three Hartmannella strains. Bacillus megaterium, Bacillus subtilis, Chromatium vinosum, Micrococcus luteus and Pseudomonas fluorescens were more easily lysed than the other bacteria tested. Agrobacterium tumefaciens, Klebsiella aerogenes and Serratia marcescens were hardly affected at all by the amoebal bacteriolytic activities. Among the Gram-negative bacteria we observed differences in lysis sensitivity while the Gram-positive bacteria tested were sensitive to lysis. Isoelectric focusing (IEF) gel-electrophoresis in the pH range 3-10 was performed to separate the bacteriolytic isoenzymes of amoebae. Bacteriolytic patterns were shown by using an activity assay in which lysis bands were formed in the agar/bacteria gel-overlay. The activity assay revealed remarkable differences in typical banding patterns for bacteriolytic activities among amoebae. Distinct differences between typical pI points of bacteriolytic activities in Acanthamoeba and Hartmannella were shown. Bacteriolytic activities of Hartmannella were more pronounced and observed in the isoelectric points (pI) range of 4.0-9.3 while for Acanthamoeba the range was pI 4.5-8.9.

Acanthamoeba↗
PubMed1979

Effect of leukocyte hydrolases on bacteria. XIV. Bacteriolytic effects of human sera, synovial fluids, and purulent exudates on Staphylococcus aureus and Streptococcus faecalis: modulation by Cohn's fraction II and by polyelectrolytes.

Normal sera and plasma, derived from humans, calves, rats, rabbits, horses, human synovial fluids, inflammatory exudates, and leukocyte extracts, when sufficiently diluted are highly bacteriolytic for Staph, aureus, Strep. faecalis, B. sutilis and to a variety of gram-negative rods. On the other hand, concentrated serum or the other body fluids are usually not bacteriolytic for these bacterial species. While the lysis of Staph, aureus and B. subtilis by diluted serum is not lysozyme dependent, lysis of Strep. faecalis is absolutely dependent on the concentration of lysozyme. The lytic factor in human serum is present in Cohn's fractions III, IV, and V. It is nondialyzable, resistant to heating for 75 degrees C and 20 min, and acts optimally at pH 5.0. Like leukocyte extracts, synovial fluids, and inflammatory exudates, it lyses only young staphylococci. The inability of concentrated serum to lyse Staph. aureus and Strep. faecalis is due to the presence in the gamma globulin fraction of a potent inhibitor, which can be partly removed by dilution of by adsorption upon the homologous bacteria. Lysis of the bacteria is also strongly inhibited by Cohn's fraction II (gamma globulin) by high-molecular-weight DNA, heparin, liquoid, and histone. The possible role played by serum globulin in the protection of bacteria against degradation by leukocyte is discussed.

Animals↗
PubMed1980

Bacteriolytic activity of human gingival exudate.

We investigated the bacteriolytic activity of gingival crevicular fluid (CF) on 14C-labeled Streptococcus faecalis, Streptococcus mutans, Staphylococcus aureus, and on whole dental plaque. CF was collected from 100 healthy donors pooled and centrifuged at 200 g. CF supernate and a frozen and thawed extract of the pellet were interacted with the different bacterial strains, while Streptococcus faecalis and Staphylococcus aureus released 60% and 75% of the radioactive label, only 38% of it was solubilized from Streptococcus mutans, following their incubation with the CF supernate. The findings agreed with results obtained by interacting bacteria with a frozen and thawed lysate of human peripheral blood leukocytes. On the other hand, extracts from frozen and thawed CF pellet were inactive. Further, lipoteichoic acid and lipopolysaccharide were released by CF from Gram-positive and Gram-negative bacteria, respectively. The role of bacteriolytic factors, present in CF, as a result of the interaction between microorganisms and leukocytes at inflammatory sites is discussed.

Actinomyces↗
PubMed1991

Comparison of group I and II soluble phospholipases A2 activities on phagocytic functions of human polymorphonuclear and mononuclear phagocytes.

Soluble phospholipase A2 (PLA2) purified from rheumatoid synovial fluid (group II) and repurified Naja naja venom PLA2 (group I) were compared for their influence on phagocytic activity of human polymorphonuclear (PMN) and mononuclear (MO) phagocytes. Group II PLA2 reduced chemotaxis, adhesiveness, and intracellular bactericidal activity (ICBA) and induced release of muramidase from PMNs. Group I PLA2 suppressed chemotaxis, and enhanced ICBA but had no influence on other phagocytic functions. Group II PLA2 purified from synovial fluid or from placenta caused marked spontaneous superoxide generation followed by inhibition of phagocytosis-induced burst of energy. Group I Naja naja and porcine pancreatic PLA2 had no effect on superoxide generation. Group II but not group I PLA2 reduced markedly ICBA of monocytes. It may be concluded that human group II soluble PLA2, in concentrations comparable to those present in inflamed joints or in sera of patients with active arthritis or septic shock, causes spontaneous formation of the oxygen radical superoxide and release of lysosomal enzymes, and suppresses conventional phagocytic activities of PMNs and monocytes. Marked differences between group I and group II PLA2s may mean that these enzymes exert different influences on cell membrane.

Arthritis, Rheumatoid↗