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PubMed1992

Autolysis of Clostridium acetobutylicum ATCC 824.

The optimum conditions for autolysis of Clostridium acetobutylicum ATCC 824 were determined. Autolysis was optimal at pH 6.3 and 55 degrees C in 0.1 M-sodium acetate/phosphate buffer. The ability of cells to autolyse decreased sharply at the end of the exponential phase of growth. Lysis was stimulated by monovalent cations and compounds that complex divalent cations, and inhibited by divalent cations. The autolysin of C. acetobutylicum, which was mainly cytoplasmic, was purified to homogeneity and characterized as a muramidase. The enzyme was identical to the extracellular muramidase in terms of M(r), isoelectric point and NH2-terminal amino acid sequence. The autolysin was inhibited by lipoteichoic acids and cardiolipin but not by phosphatidylethanolamine and phosphatidylglycerol. A mechanism of regulation and fixation involving lipoteichoic acid, cardiolipin and divalent cations is proposed.

Amino Acid Sequence↗
PubMed1992

Bactericidal activities of lysozyme and aprotinin against gram-negative and gram-positive bacteria related to their basic character.

Bactericidal properties of aprotinin, a proteinase inhibitor and possibly a defence molecule in bovine species, and of chicken egg white lysozyme, known as muramidase, were investigated. Incubation of various bacteria in the presence of either aprotinin or lysozyme showed that both proteins killed Gram-positive as well as Gram-negative bacteria without addition of complement or EDTA. Denaturation of the two proteins by dithiothreitol did not lead to loss of their bactericidal potency. Electron microscopic examination of Escherichia coli incubated either with lysozyme or aprotinin revealed that the bacterial cytoplasms gradually disintegrated. Both aprotinin and lysozyme were demonstrated within the affected cytoplasm by immunogold labelling. The results suggest that the bactericidal potency of lysozyme is not only due to muramidase activity but also to its cationic and hydrophobic properties. The bactericidal activity of aprotinin is probably also related to both these properties rather than to its activity as proteinase inhibitor.

Animals↗
PubMed1999

Germination-specific cortex-lytic enzymes from Clostridium perfringens S40 spores: time of synthesis, precursor structure and regulation of enzymatic activity.

Germination-specific enzymes, an amidase and a muramidase, of Clostridium perfringens S40 were synthesized at the time of forespore formation during sporulation. The amidase had a unique precursor structure consisting of four domains: the N-terminal pre-sequence, the N-terminal pro-sequence, mature enzyme and the C-terminal pro-sequence. The N-terminal pre-sequence and the C-terminal pro-sequence were sequentially processed at the time of development of phase-bright spores, and the resulting inactive pro-enzyme was activated by cleavage of the N-terminal pro-sequence with a specific protease during germination. A possible mechanism for the regulation of activity of muramidase, which is produced as a mature form and does not need processing for activation, is presented.

Amidohydrolases↗
PubMed1998

Multibacillary leprosy: lesions with macrophages positive for S100 protein and dendritic cells positive for Factor 13a.

In the defense against Mycobacterium leprae, macrophages play an essential part in the mechanism of bacterial lysis but require the presence of cytokines such as interleukin 2 and gamma interferon from lymphocytes in order to effectively kill the organisms in any number. While there have been many studies of the lymphocytes in lesions of leprosy, less attention has been given to the immunohistochemical characterization of the macrophage populations. In this study, the cutaneous lesions of 69 patients with leprosy (42 lepromatous, 5 mid-borderline, and 22 tuberculoid) were evaluated by immunohistochemistry for the expression of S100 protein, CD1a, CD68, muramidase, HLA-DR, and Factor 13a. The macrophages from lesions of polar, subpolar, and borderline lepromatous leprosy patients expressed S100 protein intensely and constantly. In contrast, the lesions of polar and subpolar tuberculoid leprosy had very few cells that were immunoreactive for S100 protein ('S100+') in the granulomas in the dermis. The macrophages in all lesions were reactive for CD68 and muramidase. In paraffin sections, macrophages of lepromatous lesions failed to stain for HLA-DR, whereas in tuberculoid lesions, they were strongly positive for HLA-DR. Three patients with histoid leprosy (relapse lesions) had lesions that were strongly positive for Factor 13a and were negative for S100 protein ('S100-'). Given the possible chemotactic and migration inhibition effects of the calcium-binding proteins of the S100 family, these data suggest a possibly important role for S100 protein in the accumulation of macrophages in lepromatous leprosy, and also reveal infection of Factor 13a + dermal dendritic cells in histoid leprosy.

Antigens, CD↗
PubMed1987

Penicillin tolerance in Streptococcus faecium ATCC 9790.

Tolerant strains of Streptococcus faecium had higher levels of muramidase 2 and lower levels of trypsinactivable muramidase 1 than did susceptible strains. Susceptible strains lysed faster than did tolerant strains in buffer and at some antibiotic concentrations. The addition of Triton X-100 produced equal lysis rates for susceptible and tolerant cultures.

Bacteriolysis↗
PubMed1987

Structure of Bordetella pertussis peptidoglycan.

Bordetella pertussis Tohama phases I and III were grown to the late-exponential phase in liquid medium containing [3H]diaminopimelic acid and treated by a hot (96 degrees C) sodium dodecyl sulfate extraction procedure. Washed sodium dodecyl sulfate-insoluble residue from phases I and III consisted of complexes containing protein (ca. 40%) and peptidoglycan (60%). Subsequent treatment with proteinase K yielded purified peptidoglycan which contained N-acetylglucosamine, N-acetylmuramic acid, alanine, glutamic acid, and diaminopimelic acid in molar ratios of 1:1:2:1:1 and less than 2% protein. Radiochemical analyses indicated that 3H added in diaminopimelic acid was present in peptidoglycan-protein complexes and purified peptidoglycan as diaminopimelic acid exclusively and that pertussis peptidoglycan was not O acetylated, consistent with it being degraded completely by hen egg white lysozyme. Muramidase-derived disaccharide peptide monomers and peptide-cross-linked dimers and higher oligomers were isolated by molecular-sieve chromatography; from the distribution of these peptidoglycan fragments, the extent of peptide cross-linking of both phase I and III peptidoglycan was calculated to be ca. 48%. Unambiguous determination of the structure of muramidase-derived peptidoglycan fragments by fast atom bombardment-mass spectrometry and tandem mass spectrometry indicated that the pertussis peptidoglycan monomer fraction was surprisingly homogeneous, consisting of greater than 95% N-acetylglucosaminyl-N-acetylmuramyl-alanyl-glutamyl-diaminopimelyl++ +-alanine.

Acetylation↗
PubMed1996

Evidence that the PBP 5 synthesis repressor (psr) of Enterococcus hirae is also involved in the regulation of cell wall composition and other cell wall-related properties.

psr has been reported by M. Ligozzi, F. Pittaluga, and R. Fontana, (J. Bacteriol. 175:2046-2051, 1993) to be a genetic element located just upstream of the structural gene for the low-affinity penicillin-binding protein 5 (PBP 5) in the chromosome of Enterococcus hirae ATCC 9790 and to be involved in the repression of PBP 5 synthesis. By comparing properties of strains of E. hirae that contain a full-length, functional psr with those of strains that possess a truncated form of the gene, we have obtained data that indicate that psr is involved in the regulation of several additional surface-related properties. We observed that cells of strains that possessed a truncated psr were more sensitive to lysozyme-catalyzed protoplast formation, autolyzed more rapidly in 10 mM sodium phosphate (pH 6.8), and, in contrast to strains that possess a functional psr, retained these characteristics after the cultures entered the stationary growth phase. Cellular lytic properties did not correlate with differences in the cellular contents of muramidase-1 or muramidase-2, with the levels of PBP 5 produced, or with the penicillin susceptibilities of the strains. However, a strong correlation was observed with the amounts of rhamnose present in the cell walls of the various strains. All of the strains examined that possessed a truncated form of psr also possessed approximately one-half of the rhamnose content present in the walls of strains that possessed a functional psr. These data suggest that psr is also involved in the regulation of the synthesis of, or covalent linkage to the cell wall peptidoglycan of, a rhamnose-rich polysaccharide. These differences in cell wall composition could be responsible for the observed phenotypic differences. However, the multiple effects of psr suggest that it is part of a global regulatory system that, perhaps independently, affects several cell surface-related properties.

Bacterial Proteins↗
PubMed1987

Cloning, purification, and biochemical characterization of the pneumococcal bacteriophage Cp-1 lysin.

Cp-1, a small virulent bacteriophage infecting Streptococcus pneumoniae, encodes its own lytic enzyme (CPL). A fragment of Cp-1 DNA containing the gene cpl coding for CPL was cloned and expressed in high amounts in Escherichia coli. CPL was purified to electrophoretic homogeneity by using affinity chromatography on choline-Sepharose (T. Briese and R. Hakenbeck, Eur. J. Biochem. 146:417-427, 1985), and the enzyme showing a Mr of 39,000 was characterized as a muramidase. This muramidase required for in vivo and in vitro activity the presence of choline in the teichoic acids of the pneumococcal cell walls. Free choline or lipoteichoic acid noncompetitively inhibited the activity of CPL.

Bacteriophages↗
PubMed1977

Lysozyme: a brief review.

Serum lysozyme (muramidase) estimation is a simple, convenient and useful laboratory investigation. A review of the literature shows that lysozyme has been implicated as an aetiological factor in various disorders, and credited with being a prognostic indicator in acute myeloid leukaemia, but these promises have not been fulfilled. This low molecular weight protein is found in the urine of some patients with renal tubular disorders, but some workers have emphasized its importance as a causal agent in hypokalaemia of acute myeloid leukaemia. Research should be concentrated on muramidase as an expression of cell functions rather than as an aetiological factor. Hypokalaemia in acute myeloid leukaemia may be caused by an unidentified substance of molecular weight similar to that of lysozyme.

Animals↗
PubMed1973

Periodic hematopoiesis in human cyclic neutropenia.

Human cyclic neutropenia is characterized by severe depression of blood neutrophil levels approximately every 21 days. To investigate the mechanism of cyclic neutropenia four patients were studied with daily complete blood counts, serial bone marrow examinations, marrow reserve testing, serum muramidase determinations, DF(22)P granulocytokinetic studies, and, in one patient, in vivo [(3)H]TdR labeling. Periodogram analysis of the serial blood counts in the latter patient and visual inspection of multiple cycles in the others revealed periodic fluctuations in the levels of blood neutrophils, monocytes, lymphocytes, reticulocytes, and platelets. Rhythmic changes in the morphologic and radioisotopic studies as well as the marrow reserve tests and muramidase measurements were consonant with a mechanism of periodic failure of marrow production rather than peripheral destruction. Human cyclic neutropenia is analogous to cyclic neutropenia in the grey collie dog and may be viewed as the consequence of cyclic hematopoiesis.

Agranulocytosis↗
PubMed2000

Intracellular glucosaminidase of the bacterium Xanthomonas campestris IBPM B-124: purification and properties.

A system of intracellular autolytic enzymes of the bacterium Xanthomonas campestris IBPM B-124 was found to include enzymes with muramidase and glucosaminidase activities, while a system of extracellular bacteriolytic enzymes of the same bacterium includes muramidase, muramoylalanine amidase, and endopeptidase. Using a purification technique including fractional precipitation with ammonium sulfate, gel-filtration on Toyopearl HW-55F, and FPLC ion-exchange chromatography on Mono Q, a preparation of intracellular glucosaminidase was purified 435-fold with 16% yield (SDS-PAGE data indicated the presence of minor protein contaminants). Some physicochemical properties of the purified enzyme were determined: molecular mass 26 kD, Km = 5.6 x 10(-4) M with p-nitrophenyl-2-acetamido-2-deoxy-beta-D-glucopyranoside as the substrate, and pH optimum 8.0-8.5. The enzyme is active over a wide range of Tris-HCl buffer concentrations (0.01-0.5 M) and has temperature optimum at 37-40 degrees C. The glucosaminidase activity is sensitive to p-chloromercuribenzoate (PCMB), phenylmethylsulfonyl fluoride (PMSF), and the disodium salt of ethylenediamine tetraacetic acid (EDTA). The properties of this glucosaminidase markedly differ from those of all extracellular bacteriolytic enzymes of Xanthomonas campestris. These findings indicate that the system of autolytic enzymes of this bacterium functions independently and is not connected with the system of extracellular bacteriolytic enzymes.

Ammonium Sulfate↗
PubMed1991

[Immunological study of lysates from the cell wall of group A Streptococcus].

The chemical composition and presence of immunogenic components in the lysates of the cell walls of group A Streptococcus, type M29, were studied. The lysates were prepared with the use of muramidase. Fc-Receptors were detected in the lysates. Within the first 30 minutes of cell wall lysis by muramidase, 4 times higher amounts of the protein reacting with fibrinogen excreted than in the subsequent 4 hours. The lysates contained immunogenic proteins. Fraction III isolated by chromatography of the 30-minute lysate on DEAE-trisacryl formed a single precipitation band with lysate antiserum. The lysate Fraction IV forming three precipitation bands contained a protein not specific of the type. The protein was identical to the protein antigen from Triton X-100 extracts of group A Streptococcus, types M1, M12 and M29. The group-specific polysaccharide was detected in the lysate Fraction I and Fraction II of the 4-hour lysate.

Bacterial Proteins↗
PubMed1990

Antibacterial mechanisms of lysozyme on Streptococcus mutans.

Lysozyme is a dominant member of the antibacterial complex of human saliva and has the potential to kill bacteria by direct lysis or by mechanisms (not completely understood) that are independent of its muramidase activity. The muramidase-independent bactericidal activity appears to depend upon its cationic character. Bacterial death may be due to inhibition of nutrient transport (eg. glucose) and disruption of membrane integrity. This review also describes common bactericidal mechanisms of several cationic peptides/proteins to support the cationic-dependent bactericidal model of lysozyme.

Cations↗
PubMed1989

Differences in virulence between two strains of Streptococcus suis type II after experimentally induced infection of newborn germ-free pigs.

Fifteen newborn germ-free pigs were inoculated with 2 strains, D-282 and T-15, of Streptococcus suis type II. Some pigs also were preinoculated with Bordetella bronchiseptica, which successfully predisposed them to S suis infection. The 2 streptococcal strains were differentiated by muramidase treatment, which released certain high molecular-weight proteins, termed muramidase-released proteins (MRP), from the cell wall of strain D-282, but not from the cell wall of strain T-15. Only strain D-282 (MRP-positive) induced clinical signs of disease and markedly increased neutrophil numbers in pigs. Streptococci were more frequently isolated from fecal swab specimens obtained from pigs inoculated with strain D-282 (MRP-positive) than from specimens obtained from pigs inoculated with strain T-15 (MRP-negative). Both strains were isolated from nasal swab specimens obtained from all infected pigs. Postmortem examination revealed fibrinopurulent meningitis, polyserositis, and polyarthritis in pigs inoculated with strain D-282; this strain was isolated from the CNS, serosae, visceral organs, heart, and joints. Whereas strains D-282 caused several pathologic changes, strain T-15, isolated from the lungs, caused only pneumonia. Both strains were isolated from the tonsils of all pigs. Virulence differed distinctly between the MRP-positive and the MRP-negative strains.

Animals↗
PubMed1983

[Methodological error in clinical lysozyme determinations].

In 152 sera and 40 synovial fluids of 192 patients from 3 different diagnostic groups the level of muramidase was studied comparatively with the lysoplate method. Despite the similar correlations of mean values and standard deviations of the results in the single groups, en detail these are significantly different. With an increasing mean value of 1 U (mg/l) the standard deviation is elevated by 0.1-0.25 U, for an elevation of s by 1 U mean varied between 3.8 and 9.7 U. This might be of interest for the clinical interpretation esp. of low muramidase values.

Humans↗
PubMed1980

Giant cell myocarditis.

Giant cell myocarditis (GCM) as a distinct disease entity has been questioned. The superficial morphologic resemblance to cardiac sarcoidosis and incomplete histopathologic assessment of extracardiac organ systems in reported cases has suggested that GCM represents a predominant cardiac manifestation of generalized sarcoidosis. The morphologic and immunocytochemical features at autopsy of this rare disorder were seen in a 15-year-old boy. All other organs were free of granulomatous inflammation. Transition from normal myocardial fibers to giant cells was observed, without a limiting plasma membrane between the two different aspects of the fiber. Immunocytochemistry for cytoplasmic muramidase (CM) showed CM in neutrophils and tissue macrophages. Cytoplasmic muramidase was distinctly absent from the characteristic giant cells. The classification of GCM as a disease separate from generalized sarcoidosis may be justified.

Adolescent↗
PubMed1976

Stimulatory effect of staphylococcal leukocidin on granulopoiesis disturbed by cytostatic agents.

Functional tests of granulopoiesis (leukocytosis, bone marrow picture, incubation in vitro of bone marrow with [3H]thymidine followed by radioautography and counting of labeled promyelocytes and myelocytes, serum muramidase level, liberation of granulocyte bone marrow reserve, Nitro-BT reduction in blood granulocytes, enzyme cytochemistry, and phagocytosis) were performed in rabbits given bubulphan (10 mg/kg) or 5-fluorouracil (200 mg/kg). Determinations were carried on serially during treatment with cytostatics. Some of the cytostatic-treated animals received intravenous (i.v.) injections of purified staphylococcal leukocidin in daily doses of 0.1 mg/kg. In control animals, theleukocidin resulted in stimulation of granulopoiesis (leukocytosis, increased number of [3H]thymidine-labeled myelocytes, elevated serum muramidase level). Animals receiving cytostatics suffered from marked inhibition of granulopoiesis accompanied by decrease of bone marrow granulocyte reserve. Injection of staphylococcal leukocidin during the period of myelosuppression evoked by cytostatics resulted in partial protection of granylopoiesis and faster regeneration of the leukocyte system.

Animals↗
PubMed1987

Cardiac myxoma. A retrospective immunohistochemical study.

Seven cardiac myxomas were studied by immunoperoxidase and immunofluorescence in formalin fixed and paraffin embedded tissues. Specific antisera to factor VIII related antigens, vimentin, myosin of smooth muscle, actin, desmin, alpha-1-antitrypsin, muramidase, fibrin and prekeratin antigens were used. All myxoma cells reacted positively with antibodies to vimentin and showed no staining reaction with antibodies to alpha-1-antitrypsin, muramidase, myosin, or prekeratin. Factor VIII related antigen was found only in endothelial cells and not in myxoma cells proper. Fibrin was found in patchy areas within the stroma. Antisera to actin and desmin failed to react with formalin fixed tissue. Our results suggest that the main cellular component of cardiac myxoma is a primitive mesenchymal cell without immunohistochemical evidence of more specific differentiation.

Actins↗