Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “MURAMIDASE”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 343 records · Page 19Linked to original sources
PubMed1982

Effect of chloroquine on the stability of rat kidney lysosomes in vivo and in vitro.

1. Chronic administration of chloroquine to rats results in increased urinary excretion of lysosomal acid phosphatase, muramidase and cathepsin D. 2. Various concentrations of chloroquine caused lysosomal membrane swelling as shown by decrease of light absorbance in lysosomal suspensions. 3. Incubating lysosomal suspensions in the presence of chloroquine resulted in a marked lysosomal acid phosphatase release. 4. Addition of acetylsalicylic acid, a lysosomal membrane stabilizer, into a lysosomal suspension containing chloroquine, reduced the degree of lysosomal membrane swelling and acid phosphatase release. 5. The results suggest a labilizing effect of chloroquine on rat kidney lysosomes.

Acid Phosphatase↗
PubMed1982

Renal effects of an aminoglycoside antibiotic in the rat.

The renal effect of the daily administration of gentamicin to male albino rats (20 mg/kg body weight) for 6 consecutive days on some biochemical systems of the kidney was examined. Urine volume and urinary protein levels were found to be progressively raised following gentamicin. Urinary alkaline phosphatase, acid phosphatase, muramidase and glutamate dehydrogenase (GDH) activities were found to be markedly elevated. Acid phosphatase and GDH activities in urine were raised 24 h and 48 h, respectively, from the onset of gentamicin administration. The sequence in which some regions of the renal cells were involved in gentamicin nephrotoxicity was determined and the probable mechanism of interaction of gentamicin antibiotic with the renal tubular cells is proposed.

Acid Phosphatase↗
PubMed2004

Host defense proteins in vernix caseosa and amniotic fluid.

OBJECTIVE: This study was undertaken to define the spectrum, activity, and spatial distribution of antimicrobial peptides in vernix caseosa and amniotic fluid in the absence of clinical chorioamnionitis. STUDY DESIGN: Characterization of innate immune proteins in vernix and amniotic fluid obtained from pregnancies with gestational ages greater than 37 weeks by Western analysis, immunohistochemistry, and antimicrobial growth inhibition assay. RESULTS: Lysozyme, lactoferrin, human neutrophil peptides 1-3, and secretory leukocyte protease inhibitor were identified by Western analysis in vernix suspensions (n = 25) and amniotic fluid samples (n = 10). Three other important antimicrobial proteins, human beta defensin-2, lactoperoxidase, and LL-37 were not detected. Amniotic fluid and soluble extracts of vernix exhibited muramidase (lysozyme) activity, and there was selective efficacy in inhibiting growth of common perinatal pathogens. Antimicrobial peptides were concentrated in discrete, organized, acellular "granules" embedded in the vernix lipid matrix. CONCLUSION: In the absence of chorioamnionitis, vernix and amniotic fluid contain an organized pool of antimicrobial peptides with a defined spectrum of bioactivity against common bacterial and fungal pathogens.

Adolescent↗
PubMed1990

Multilayer adsorption of lysozyme on a hydrophobic substrate.

Macromolecular adsorption is known to occur as a complex process, often in a series of steps. Several models are discussed in the literature which describe the microscopic structure of the adsorbate. In the present study we investigated the adsorption of hen egg white lysozyme on alkylated silicon oxide surfaces. A combination of fluorescence excitation in the evanescent field and fluorescence recovery after photobleaching allowed us to measure the amount of adsorbed fluorescent lysozyme and the equilibrium exchange kinetics with molecules in solution. We found that a model with at least three classes of adsorbed molecules is necessary to describe the experimental results. A first layer is formed by the molecules which adsorb within a short time after the beginning of the incubation. These molecules make up approximately 65% of the final coverage. They are quasi-irreversibly adsorbed and do not measurably exchange with bulk molecules within one day even at temperatures up to 55 degrees C. A second layer, which reaches equilibrium only after several hours of incubation, shows a pronounced exchange with bulk molecules. The on-off kinetics show a distinct temperature dependence from which an activation barrier of delta E approximately 22 kcal/mol is derived. A third layer of molecules that exchange rapidly with the bulk can be seen to comprise approximately 10% of the total coverage. The exchange rate is on the order of fractions of a second. The binding of the latter two classes of adsorbed molecules is exothermic. From the temperature dependence of the coverage, the binding enthalpy of the slowly exchanging layer was estimated to be delta Hads approximately 3.8 kcal/mol. The second and third class of molecules remain enzymatically active as a muramidase, which was tested by the lysis of the cell walls of Micrococcus lysodeiktikus. The molecules in the first layer, on the other hand, showed no enzymatic activity.

4-Chloro-7-nitrobenzofurazan↗
PubMed1987

Fibronectin concentrations in lung lavage fluid after inhalation exposure to low levels of metals.

Groups of rabbits were exposed by inhalation to chlorides of cobalt, nickel, and manganese as well as to tri- and hexavalent chromium at metal concentrations ranging from 0.4 to 3.9 mg/m3 for 1-4 months (5 days/week, 6 hr/day). Fibronectin content and lysozyme (muramidase) activity in lavage fluid were measured after all treatments and in alveolar macrophages after treatment with nickel chloride. In the lavage fluid no marked changes were seen in fibronectin content and lysozyme activity after exposure to tri- or hexavalent chromium or manganese. Nickel exposure significantly decreased the lysozyme activity in the lavage fluid and in the macrophages whereas the fibronectin content was unchanged in the lavage fluid and significantly increased in the macrophages. Both fibronectin content and lysozyme activity were increased markedly in the lavage fluid after cobalt exposure.

Administration, Inhalation↗
PubMed2001

Genetic evidence that antibacterial activity of lysozyme is independent of its catalytic function.

A catalytically inactive mutant of hen egg white lysozyme was constructed by site-directed mutagenesis to elucidate the role of enzymatic activity on its antimicrobial activity against Gram-positive bacteria. The catalytic residue aspartic acid at position 52 of lysozyme was substituted with serine (D52S-Lz) and the mutant cDNA was inserted into a yeast expression vector, pYES-2. Western blot analysis indicated that the mutation did not affect secretion of the D52S-Lz lysozyme into the medium of the expressing Saccharomyces cerevisiae, INVSC1. In addition, circular dichroism and fluorescence spectral analysis revealed no change in the structure of D52S-Lz compared to that of wild-type (Wt-Lz) lysozyme. The mutation (D52S) abolished the catalytic activity of lysozyme. Antimicrobial tests against Staphylococcus aureus and Bacillus subtilis revealed that the catalytically inactive D52S-Lz was as bactericidal as the Wt-Lz lysozyme. Heat treatment leading to enzyme inactivation had no effect on the bactericidal activity of either wild-type or the mutant D52S-Lz lysozyme. The binding affinity of D52S-Lz to the isolated peptidoglycan of S. aureus was unaffected. Our results provide the first demonstration of direct genetic evidence that the antimicrobial activity of lysozyme is operationally independent of its muramidase activity, and strongly suggest the antimicrobial action of lysozyme is due to structural factors.

Anti-Bacterial Agents↗
PubMed1999

The non-enzymatic microbicidal activity of lysozymes.

T4 lysozyme was thought to destroy bacteria by its muramidase activity. However, we demonstrate here that amphipathic helix stretches in the C-terminus of T4 lysozyme mediate its bactericidal and fungistatic activities. In heat-denatured T4 lysozyme, the enzymatic activity is completely abolished but unexpectedly, the antimicrobial functions remain preserved. Small synthetic peptides corresponding to amphipathic C-terminal domains of T4 lysozyme show a microbicidal activity. Its membrane disturbing activity was directly demonstrated for bacterial, fungal and plant cells but not in a hemolysis assay. Comparable results were obtained with hen egg white lysozyme. This opens up many new opportunities for optimization of lysozymes as antimicrobial agents in various applications by protein engineering.

Animals↗
PubMed1988

Immunohistochemical observation of S-100 protein and neuron specific enolase in the tumour cells of granular cell tumour.

An immunohistochemical technique for the detection of S-100 protein, neuron specific enolase (NSE), carcinoembryonic antigen (CEA) and muramidase (lysozyme) was applied to a case of the granular cell tumour. S-100 protein was detected both in the nuclei and cytoplasma of the granular cells, and NSE was weakly positive in their cytoplasms. CEA and lysozyme were negative in the tumour cells. Our results supports the concept that granular cell tumours are derived from Schwann cells.

Adult↗
PubMed1984

Applications of immunohistochemistry to ophthalmic pathology.

Immunohistological techniques have been increasingly used, both in general and ophthalmic pathology, for identification of specific cell types that may not be possible on morphological grounds or by conventional histochemical methods alone. Enzyme conjugate techniques using the peroxidase-antiperoxidase (PAP) immune complex method and the avidin-biotin-horseradish peroxidase method (ABC) are particularly useful as they are highly sensitive, provide permanent results, allow the use of paraffin-embedded tissues and do not require a fluorescent microscope. Antibodies against glial fibrillary acidic protein (GFAP), factor VIII-related antigen, muramidase, S-100 protein, myoglobin, prostatic acid phosphatase and prostate-specific antigen are valuable tools in surgical pathology and their applicability to ophthalmic pathology have been clearly demonstrated.

Acid Phosphatase↗
PubMed1985

Sympathetic ophthalmia. An immunohistochemical study of epithelioid and giant cells.

There is controversy regarding the origin of the pigment-containing epithelioid cells in the uvea of eyes with sympathetic ophthalmia. The results of the present immunocytochemical study demonstrating the presence of muramidase and S-100 protein in these cells, and the binding of peanut lectin by the pigment-containing cells support the interpretation that the pigment-containing epithelioid cells and giant cells are of monocytic (histiocytic) origin. Our study also emphasizes the diverse functional capacity of these epithelioid cells.

Epithelium↗
PubMed1985

Acute monocytic leukemia recurring as bilateral perilimbal infiltrates. Immunohistochemical and ultrastructural confirmation.

A 28-year-old woman developed leukopenia and slight cervical lymphadenopathy. Bone marrow aspiration and special stains established the diagnosis of acute monocytic leukemia. Following chemotherapy a complete hematologic remission was elicited. Seven months later, she consulted an ophthalmologist because of bilateral conjunctival lesions. Ophthalmologic examination showed subconjunctival, perilimbal grayish-pink infiltrates. A conjunctival biopsy disclosed sheets of mononuclear cells consistent with acute monocytic leukemia. Four months later, she developed cutaneous lesions in the face and chest wall. Subsequent biopsies of conjunctiva and skin and immunohistochemical demonstration of muramidase in the tumor cells supported the diagnosis of monocytic leukemia. Electron microscopic studies were particularly valuable and disclosed that more than 80% of the leukemic cells contained two types of cytoplasmic complexes of rough endoplasmic reticulum that displayed both tubular and helical configurations. These complexes differed morphologically from the ribosome-lamellar complexes observed in hairy cell leukemia and other hematologic disorders.

Adult↗
PubMed1983

Differential staining pattern of lysozyme in palisading granulomas: an immunoperoxidase study.

Biopsies from palisading granulomas of granuloma annulare, necrobiosis lipoidica, and rheumatoid nodules were examined for the presence of lysozyme (muramidase). This enzyme was identified in paraffin-embedded tissues using a primary antibody to lysozyme and the peroxidase-antiperoxidase technic. Some inflammatory cells in the infiltrate of granuloma annulare stained abundantly for lysozyme, whereas those of necrobiosis lipoidica and rheumatoid nodule stained minimally and negatively, respectively. This pattern of staining may be of diagnostic value and suggests that the histiocytoid cells constituting the infiltrate of granuloma annulare are in some way different from the similar-appearing cells of necrobiosis lipoidica and rheumatoid nodule.

Granuloma↗
PubMed1999

Presence of the Streptococcus suis suilysin gene and expression of MRP and EF correlates with high virulence in Streptococcus suis type 2 isolates.

Nineteen Streptococccus suis type 2 isolates that had been analyzed previously for hemolysin production, ribotype, and virulence in pigs were examined for presence of the gene coding for suilysin by PCR amplification, and southern blot and hybridization techniques. Based on southern blot and hybridization analysis, all isolates tested contained at least a portion of the suilysin gene. PCR amplification of the entire gene resulted in gene fragments from five of the seven highly virulent isolates and none of the moderately virulent or avirulent isolates. Additional PCR analysis showed that mutation or deletions at the 5' end of the suilysin gene in the less virulent isolates prevented amplification of the sly gene fragment from those isolates. The MRP+ (muramidase-released protein) EF+ (extracellular protein) phenotype was also expressed by the same five highly virulent/sly+ isolates.

Animals↗
PubMed2005

Structural and functional modeling of human lysozyme reveals a unique nonapeptide, HL9, with anti-HIV activity.

We previously reported that lysozyme accounts for anti-HIV activity associated with the beta-core fraction of human chorionic gonadotropin [Lee-Huang, S., Huang, P. L., Sun, Y., Kung, H. F., Blithe, D. L. & Chen, H. C. (1999) Proc Natl Acad Sci U S A 96, 2678-81]. To define the structural and sequence requirements for anti-HIV activity, we carried out peptide fragmentation and activity mapping of human lysozyme. We identified two peptides that consist of 18 and 9 amino acids of human lysozyme (HL18 and HL9), corresponding to residues 98-115 and 107-115. HL18 and HL9 are potent inhibitors of HIV-1 infection and replication with EC(50)s of 50 to 55 nM, comparable to intact lysozyme. Scrambling the sequence or substitution of key arginine or tryptophan residues results in loss of antiviral activity. HL9, with the sequence RAWVAWRNR, is the smallest peptide we identified with full anti-HIV activity. It forms a pocket with its basic residues on the surface of the molecule. HL9 exists as an alpha-helix in native human lysozyme, in a region of the protein distinct from the muramidase catalytic site. Monte Carlo peptide folding energy minimizing simulation modeling and CD studies indicate that helical propensity does not correlate with antiviral activity. HL9 blocks HIV-1 viral entrance and replication, and modulates gene expression of HIV-infected cells, affecting pathways involved in survival, stress, TGFbeta, p53, NFkappaB, protein kinase C and hedgehog signaling.

Amino Acid Sequence↗
PubMed1982

Effects of tumour cell culture supernatants on some biochemical activities of macrophages.

The following enzyme activities were measured in cell lysates and supernatants from mouse peritoneal macrophages incubated with products of cultured tumour and other cells: acid phosphatase, beta-D-glucuronidase, N-acetyl-D-glucosaminidase, muramidase (lysozyme), lactic dehydrogenase (supernatant only) and plasminogen activator (supernatant only). There were no noteworthy changes in enzyme activities. Hydrogen peroxide production by appropriately stimulated mouse and/or guinea-pig peritoneal exudate macrophages was variably inhibited by supernatants from some tumour cells and some normal cells. Changes in these biochemical activities of macrophages do not appear to be closely related to the anti-inflammatory activity of tumour cell products.

Animals↗
PubMed1997

Identification and isolation of a bactericidal domain in chicken egg white lysozyme.

Chicken egg white lysozyme exhibits antimicrobial activity against both Gram-positive and Gram-negative bacteria. Fractionation of clostripain-digested lysozyme yielded a pentadecapeptide with antimicrobial activity but without muramidase activity. The peptide was isolated and its sequence found to be I-V-S-D-G-N-G-M-N-A-W-V-A-W-R (amino acids 98-112 of chicken egg white lysozyme). A synthesized peptide of identical sequence had the same bactericidal activity as the natural peptide. Replacement of Trp 108 with tyrosine significantly reduced the antibacterial capacity of the peptide. By replacement of Trp 111 with tyrosine the antibacterial activity was lost. Replacement of Asn 106 with the positively charged arginine strongly increased the antibacterial capacity of I-V-S-D-G-N-G-M-N-A-W-V-A-W-R. The peptide I-V-S-D-G-N-G-M consisting of the eight amino acids of the N-terminal side had no bactericidal properties, whereas the peptide N-A-W-V-A-W-R of the C-terminal side retained some bactericidal activity. Replacement of asparagine 106 by arginine (R-A-W-V-A-W-R) increased the bactericidal activity considerably. The D enantiomer of R-A-W-V-A-W-R was as active as the L form against five of the tested bacteria, but substantially less active against Serratia marcescens, Micrococcus luteus, Staphylococcus aureus, Staphylococcus epidermidis and Staphylococcus lentus. For these bacterial species some stereospecific complementarity between receptor structures of the bacteria and the peptide can be assumed.

Animals↗
PubMedDate not supplied

In vitro function of granulocytes isolated from blood of normal volunteers using continuous-flow centrifugation in the IBM-aminco celltrifuge and adhesion-filtration leukapheresis using nylon fiber.

Granulocytes were harvested from each of five healthy male volunteers once by continuous flow centrifugation with the IBM-Aminco Celltrifuge, and once by adhesion filtration leukapheresis with nylon fiber. Granulocyte recovery and purity were significantly better with the filtration leukapheresis system than with continuous flow centrifugation. Measurements of trypan blue dye exclusion and muramidase activity were similar to those in control granulocytes regardless of the method of isolation. Granulocyte-stimulated oxygen consumption was diminished in granulocytes prepared by the adhesion filtration method, but normal in those prepared by continuous flow centrifugation with the IBM-Aminco Celltrifuge.

Blood Transfusion↗
PubMedDate not supplied

Effect of microaggregate blood filtration on granulocyte concentrates in vitro.

To determine the effect of transfusing granulocyte concentrates through microaggregate blood filters, granulocytes prepared with a cell processor were passed through screen and depth microaggregate filters. Pre- and postfiltration evaluations were made of total granulocyte count, levels of muramidase, granulocyte viability, motility, phagocytosis, bactericidal activity, and hydrogen peroxide-forming capacity. Compared to prefiltration levels, a significant (p less than 0.05) decrease in postfiltration granulocyte counts was seen for all the depth filters studied but not for the standard 170 microns (control) or the 40 microns screen filter. For the various tests of granulocyte function evaluated prefiltration, no significant postfiltration differences (p greater than 0.05) were seen for any of the filters studied. Screen microaggregate filters retained only 1 to 3 percent of granulocytes contained in the concentrates, and thus appear satisfactory for use in clinical transfusions. The large percentage of neutrophils retained by the depth filters (20-62%), however, precludes their use for transfusion of granulocyte concentrates.

Blood↗