Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.2.1.17 (lysozyme)
21,489 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The properties of a smooth phage resistant variant of Brucella abortus were studied in an attempt to determine the mechanism of phage resistance. This strain was fully capable of adsorbing phage but penetration, and hence replication, did not occur. No evidence of lysogeny or a phage carrier state could be obtained and gross chemical differences between the resistant strain and its phage susceptible parent were not detected. The phage resistant variant showed increased resistance to lysis from without, either by phage or by lysozyme, in the presence of chelating agents. It was concluded that resistance was the result of a modification in cell wall structure conferring resistance to lysozyme-like enzymes, thus preventing penetration of phage.
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PMID:Studies on a smooth phage resistant variant of Brucella abortus II. Mechanism of phage resistance. 81 43

The concentration of lysozyme, total immunoglobulin and bactericidal activity were measured in sera of Bos indicus cattle, retrospectively screened for specific antibodies to Brucella abortus and classified as being positive reactors or negative reactors. In addition, the effect of complement in the sera was studied to demonstrate complement dependence of antibody-mediated bacterial killing. It was observed that, under the test conditions, serum bactericidal activity and concentration of total immunoglobulin were associated with high specific antibody levels (P less than 0.001). Furthermore, there was a slight decrease in the lytic activity of lysozyme in the sera of animals with high antibody titres.
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PMID:Humoral factors of natural resistance of Bos indicus cattle selected for antibody titre to Brucella abortus. 151 60

Brucella abortus injected into CBA mice replicated primarily in the spleen and liver, reaching a peak bacterial count in both organs about 7 days postinfection. The organism was eliminated from the liver but declined to a chronic phase in the spleen. The infection caused hepatosplenomegaly. An influx of macrophages into the two organs was monitored by quantitative Northern (RNA blot) analysis of the macrophage-specific marker lysozyme mRNA. Lysozyme mRNA was detectable in spleen and increased three- to fourfold during infection. In liver, lysozyme mRNA was initially undetectable, but at about the peak of infection it reached a level comparable to that in the spleen. Macrophage colony-stimulating factor 1 (CSF-1) has been reported to be elevated in the circulation of animals infected with B. abortus and is known to stimulate monocytopoiesis. To investigate the role of CSF-1 in pathogenesis, we studied the effect of further increasing the CSF-1 concentration by administration of recombinant human CSF-1. Since the infection is characterized by several distinct phases, recombinant human CSF-1 was administered at defined times relative to these phases. Pronounced effects were observed only when CSF-1 administration was begun during the developing acute phase. The consequences were decreased bacterial numbers in the spleen but an increase in the liver, reduced antibody generation, and increased hepatosplenomegaly. A feature of many chronic intracellular infections is immunosuppression. B. abortus caused a substantial diminution of responsiveness of spleen cells to T-cell mitogens, particularly concanavalin A. This action was mimicked by CSF-1 treatment of the animals prior to spleen cell isolation. The results suggest that CSF-1 plays a role in macrophage recruitment in brucellosis and that recruited macrophages contribute to the immunopathology and immunosuppression.
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PMID:Effect of recombinant human macrophage colony-stimulating factor 1 on immunopathology of experimental brucellosis in mice. 154 70

Both Brucella abortus lipopolysaccharide (LPS) and lipid A were low activators of nitroblue tetrazolium reduction and lysozyme release in human neutrophils. The stimulation was dose dependent and was higher in the presence of autologous plasma than in its absence. The comparison between Brucella LPS and lipid A versus Salmonella LPS revealed that at least 100 times more LPS and 1,000 times more lipid A of the former genus were required to induce significant nitroblue tetrazolium reduction and a corresponding lysozyme release in neutrophils. Low Brucella LPS-mediated superoxide and lysozyme production might contribute to the survival of these facultative intracellular bacteria in phagocytic cells.
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PMID:Effect of Brucella abortus lipopolysaccharide on oxidative metabolism and lysozyme release by human neutrophils. 154 94

Badakhsh, Fred F. (University of Georgia, Athens), and John W. Foster. Detoxification and immunogenic properties of endotoxin-containing precipitate of Brucella abortus. J. Bacteriol. 91:494-498. 1966.-Endotoxin-containing precipitates (ECP) were prepared from Brucella abortus strain 19A by aqueous ether extraction followed by ethyl alcohol precipitation. Lysozyme was the most effective of several enzymes tried for detoxification of endotoxin present in the precipitate. Trypsin was shown to reduce mouse lethal toxicity but not rabbit dermal toxicity. Immunological studies of ECP and enzyme-treated ECP demonstrated that lysozyme did not harm the immunogenic property of ECP, whereas heat, ribonuclease, lipase, and proteolytic enzymes had an adverse effect. Serological reactivity of ECP was increased after lysozyme treatment, whereas ribonuclease reduced serological activity.
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PMID:Detoxification and immunogenic properties of endotoxin-containing precipitate of Brucella abortus. 495 77

The supernatant fluids of batch and continuous cultures of Brucella strains contained up to 100 mg/l of soluble RNA which could be recovered by precipitation with lysozyme, This RNA fraction had many of the properties of ribosomal RNA and was single-stranded, sensitive to ribonuclease, with an approximate sedimentation constant of 5S, a molecular weight of about 35000 daltons and an adenine; guanine; cytosine; uracil content of 17.5; 26.5; 33; 23 mol% respectively. RNA fractions from lysozyme precipitates evoked high titres of Brucella agglutinins on injection into rabbits and induced acute inflammatory responses in guinea-pig skin. Highly purified RNA fractions prepared by phenol extraction of lysozyme precipitates did not evoke antibodies to Brucella abortus.
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PMID:Isolation and properties of an RNA fraction present in Brucella culture supernatants. 615 68

The ip inoculation of inactivated Brucella abortus, strain B19 R, protected mice against a subsequent graft of an ascites lymphoma. The bacterial components responsible for this effect were investigated. Centrifugation supernatants of sonicated bacteria supposed to contain mainly cytoplasmic products did not offer protection against the lymphoma. Cell walls (CW's) prepared by enzyme digestion of pellets of lysed bacteria and checked for purity by electron microscopy prolonged survival of mice and induced cytotoxic macrophages in their peritoneal cavities. CW peptidoglycan (PG) did not seem to play an important part in this effect. Enzyme digestion of CW, in particular by lysozyme, was found to reduce a PG characteristic component (diaminopimelic acid) without altering CW antitumor activity. Conversely, a purified PG preparation did not influence tumor growth. Extraction of CW by an ether:water mixture did not alter its antitumor activity, while incubation in NaOH abolished its activity almost completely. All CW preparations were found to elicit hypersensitivity reactions in Brucella-infected animals.
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PMID:Antitumor activity of cell walls from Brucella abortus. 641 57

Polypeptide and polysaccharide outer membrane components of Brucella abortus 99 (S) were investigated by analysis of cell-wall fractions by sodium dodecyl-sulfate polyacrylamide gel electrophoresis and staining with coomassie blue and periodic acid silver stain. Crude cell-walls were deprived by Triton X-100 treatment of most cytoplasmic material as seen by electron microscopy and cytochrome determination (cell-walls). They were submitted to hot SDS to obtain intentionally after centrifugation, peptidoglycan in the insoluble fraction: SDS-I fractions or peptidoglycan sacculi, and outer membrane components in the SDS soluble fraction as for Enterobacteriaceae. The SDS-soluble fraction contained two major components: a high molecular weight broad band of smooth lipopolysaccharide (S-LPS) and a 43k polypeptide band. The SDS-I fractions were treated by lysozyme to solubilize peptidoglycan before analysis. They contained two major polypeptide groups 36-37-38k, 25-26-27k, a minor one at 31k and variable amounts of high molecular weight S-LPS. The polypeptide and polysaccharide patterns of the entire outer membrane obtained from lysozyme hydrolysed cell-walls are the sum of both SDS soluble and insoluble fraction patterns. These results mean that 25-27k and 36-38k bands are strongly bound to peptidoglycan, probably covalently. The 25-26-27k bands heavily stained for polysaccharides would be glycopolypeptides. In addition, the polysaccharide patterns of S-LPS fraction appears as a high molecular weight broad band, contrary to the multiple regularly spaced bands of high molecular weight E. coli S-LPS. The B. abortus outer membrane is composed of four major components: LPS, 43k and 36-37-38k polypeptides and 25-26-27k glycopeptides.
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PMID:Evidence of three major polypeptide species and two major polysaccharide species in the Brucella outer membrane. 641 68

Macrophage spreading, surface receptor density/avidity, phagocytosis, random migration, chemotactic responsiveness, and serum lysozyme were examined during the course of infection (up to 60 days) of mice with Brucella abortus strain 19. Markedly enhanced in vitro spreading activity was observed throughout the period of study. The density/avidity of cell surface immunoglobulin G Fc receptors was increased for up to 60 days postinfection. Internalization of sheep erythrocytes via C3 receptors was significantly enhanced. Random locomotion and chemotactic responsiveness to lymphocyte-derived chemotactic factor and N-formyl-L-methionyl-L-leucyl-L-phenylalanine were markedly stimulated. Serum lysozyme was also elevated in infected animals. These changes indicated significant and prolonged enhancement of macrophage activity during Brucella infection. These findings are discussed in relation to previous reports describing macrophage activation by Brucella.
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PMID:Characterization of macrophage functions in mice infected with Brucella abortus. 678 6

The insoluble fraction, SDS-I, obtained by boiling cell-walls of Brucella abortus in sodium dodecyl sulfate (SDS) was hydrolyzed by lysozyme. Three major bands of apparent molecular weight 37000 (I), 25000 (II), 15000 (III) were isolated by gel slicing after polyacrylamide gel electrophoresis in the presence of SDS. The three bands were injected subcutaneously to mice using Freund incomplete adjuvant and immunity was tested one month later by intraperitoneal administration of a virulent strain of B. abortus. Fifteen days after challenge, numbers of viable brucella within the spleens were determined. The isolated bands, I, II and III were able to protect mice at a level corresponding to the killed whole-cells Brucella melitensis H38 reference vaccine.
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PMID:Isolation of three Brucella abortus cell-wall antigens protective in murine experimental brucellosis. 680 61


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