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PubMed2002

Strategies for new antimicrobial proteins and peptides: lysozyme and aprotinin as model molecules.

The increasing development of bacterial resistance to traditional antibiotics has reached alarming levels, thus necessitating the strong need to develop new antimicrobial agents. These new antimicrobials should possess both novel modes of action as well as different cellular targets compared with the existing antibiotics. Lysozyme, muramidase, and aprotinin, a protease inhibitor, both exhibit antimicrobial activities against different microorganisms, were chosen as model proteins to develop more potent bactericidal agents with broader antimicrobial specificity. The antibacterial specificity of lysozyme is basically directed against certain Gram-positive bacteria and to a lesser extent against Gram-negative ones, thus its potential use as antimicrobial agent in food and drug systems is hampered. Several strategies were attempted to convert lysozyme to be active in killing Gram-negative bacteria which would be an important contribution for modern biotechnology and medicine. Three strategies were adopted in which membrane-binding hydrophobic domains were introduced to the catalytic function of lysozyme, to enable it to damage the bacterial membrane functions. These successful strategies were based on either equipping the enzyme with a hydrophobic carrier to enable it to penetrate and disrupt the bacterial membrane, or coupling lysozyme with a safe phenolic aldehyde having lethal activity toward bacterial membrane. In a different approach, proteolytically tailored lysozyme and aprotinin have been designed on the basis of modifying the derived peptides to confer the most favorable bactericidal potency and cellular specificity. The results obtained from these strategies show that proteins can be tailored and modelled to achieve particular functions. These approaches introduced, for the first time, a new conceptual utilization of lysozyme and aprotinin, and thus heralded a great opportunity for potential use in drug systems as new antimicrobial agent.

Anti-Bacterial Agents↗

PubMed2003

Detection and localization of a peptidoglycan hydrolase in Lactobacillus delbrueckii subsp. bulgaricus.

Peptidoglycan hydrolase activities in Lactobacillus delbrueckii subsp. bulgaricus were detected by analysis of bacterial extracts on denaturing polyacrylamide gel electrophoresis containing lyophilized Micrococcus lysodeikticus cells as substrate. A hydrolase with an estimated molecular mass of 80 kDa was found to cross-react on Western blot with monoclonal antibodies raised against muramidase-2 of Enterococcus hirae. These antibodies were also used to demonstrate that the method of cell sample preparation affected protein detection. Slot and Western blots indicate that the peptidoglycan hydrolase from L. bulgaricus is bound to the cell wall. Immuno-labeling followed by optical and electron microscopic observations suggest that this hydrolase is intracellular and restricted mainly to the space between the membrane and the cell wall.

Antibodies, Monoclonal↗

PubMed1975

Antipyretic effect of cycloheximide, and inhibitor of protein synthesis, in patients with Hodgkin's disease or other malignant neoplasms.

Infusion of cycloheximide i.v., an antibiotic known to inhibit synthesis of protein, at a rate of 0.2 mg/kg/hr, reliably caused lysis of fever in 15 chronically febrile patients with Hodgkin's disease who did not have detectable bacterial, fungal, or viral infection. Antipyretic effects were also seen in some patients with reticulum cell sarcoma, lymphosarcoma, acute leukemia, histiocytic medullary reticulosis, plasma cell myeloma, carcinoma of the lung, and carcinoma of the cervix. The drug failed to produce defervescence in four patients with normal granulocyte reserves, who were febrile due to bacterial infection. When infused at a rate of 0.2 mg/kg/hr, the drug apparently caused an acute alteration of protein metabolism in man in that plasma amino acid nitrogen rose acutely while plasma levels of muramidase and ribonuclease fell during the period of the infusion. The data suggest that continuing synthesis of protein may be involved in nonbacterial fever of neoplastic disease. Mammalian granulocytes and monocytes are known to elaborate a pyrogenic protein following appropriate stimulation; it is suggested that in some types of neoplastic disease, particularly Hodgkin's disease, tumor cells may produce and release a pyrogenic protein and that drug-induced inhibition of its synthesis is responsible for the observed lysis of fever.

Bacterial Infections↗

PubMedDate not supplied

Lysozyme-rich muciphages surrounding colorectal adenomas.

Muciphages are mucin-rich phagocytes believed to evolve as a result of the disruption of colorectal crypts. In a previous work we found, in rectal biopsies from patients with chronic ulcerative colitis, muciphages having not only mucin but also lysozyme, an enzyme with a potent antimicrobial activity. Recently we detected lysozyme-rich muciphages in the normal mucosa of the stalk of colonic adenomas. Filed hematoxylin and eosin (H&E)-stained sections from 30 consecutive colorectal adenomas with a stalk (lined by normal colorectal mucosa) were stained with PAS (for mucopolysaccharides), with CD68 (to label macrophages) and with lysozyme (Muramidase). Of the 30 adenomas, 16 (40%) showed muciphages in the mucosa of the stalk. Those muciphages were PAS- CD68- and lysozyme-positive. Although the significance of these findings remains elusive, it is conceivable that lysozyme-rich muciphages mirror increased cell destruction in colorectal adenomas with a high cell turnover. The possibility that lysozyme-rich muciphages surrounding adenomas are instrumental in a novel molecular mechanism of host defense, effective at the early stages of colorectal carcinogenesis, was also entertained. Such a mechanism would prevent the lateral expansion of the dysplastic epithelium of the adenoma into the surrounding normal mucosa of the stalk.

Adenoma↗

PubMed1975

Isolation and partial characterization of human eosinophil granules. Comparison to neutrophils.

Human blood eosinophils obtained from untreated patients with large numbers of circulating eosinophils were purified and lysed. An eosinophil contains 2.65 times as much peroxidase, 2.44 times as much beta-glucuronidase, approximately two times as much acid beta-glycerophosphatase, and 1.2 times as much protein as a neutrophil. Lysate filtration allowed isolation of eosinophil granules by isopycnic ultracentrifugation in sucrose. The granules had a mean density of rho 1.24 g/ml, and contained peroxidase, beta-glucuronidase, and acid beta-glycerophosphatase. They totally lacked muramidase and alkaline phosphatase. Electron micrography confirmed the isolation.

Acid Phosphatase↗

PubMed1976

Probenecid and the rat kidney: investigations by renal enzyme excretion technique.

Probenecid in doses of 640 mg/kg was administered to rats by the oral route, and the changes in five important enzymatic activities of urine were recorded thereafter for two days. The resluts exclude that probenecid impairs tubular reabsorption of low molecular weight protein, as urinary muramidase activity was not found increased. On the other hand, increased activities were encountered in those enzymatic activities in urine which derive from the renal tubular cells (ALD, G-6-PDH, LDH). These observations point towards a nephrotoxic effect of probenecid, which, however, is only of very low degree, as other "standard" enzymatic activities of urine, such as alkaline phosphatase, remained unchanged.

Animals↗

PubMed1976

Serum lysozyme in Crohn's disease and ulcerative colitis.

Serum lysozyme (muramidase) was determined in 72 patients with Crohn's disease or ulcerative colitis. Serum lysozyme was elevated in both disease groups. The mean enzyme level was significantly higher in Crohn's disease than in ulcerative colitis, but there was a considerable overlapping between the groups, which makes serum lysozyme determination of dubious value in the differential diagnosis between Crohn's disease and ulcerative colitis. No correlation was found between the serum lysozyme concentration and the activity of the diseases.

Adolescent↗

PubMed1976

Serum lysozyme in inflammatory bowel disease.

Serum lysozyme (muramidase) concentrations were measured in three groups of patients: control, ulcerative colitis and proctitis, and Crohn's disease. The mean +/-SD for each group was: control, 7 +/- 2; ulcerative colitis and proctitis, 7 +/- 2; and Crohn's disease, 10 +/- 4. Although a significant difference was seen between values in patients with Crohn's disease and values observed in those with ulcerative colitis or control patients, an important overlap was found between these groups. Further studies are necessary to explain the disparate results between this study and previous reports.

Adolescent↗

PubMedDate not supplied

Colorectal adenomas produce lysozyme.

Lysozyme is an innate non-immunologic antibacterial enzyme produced by the Paneth cells of the upper intestinal tract. Lysozyme is not normally secreted in the lower intestinal tract. Previous reports indicate, however, that lysozyme may be secreted by colorectal neoplasias. The aim was to audit lysozyme expression in colorectal diseases including neoplasias. For that purpose, sections were stained with lysozyme (Muramidase), Ki67 (MIB1) and CD 68. Intense lysozyme overexpression (+++) was compared among 177 colorectal tissues: 35 having normal mucosa, 20 regenerative mucosa in inflammatory bowel disease (IBD), 2 inflammatory polyps, 3 collagenous colitis, 2 melanosis coli, 21 hyperplastic polyps, 42 tubular adenomas, 9 serrated adenomas, 30 villous adenomas and 13 invasive carcinomas. Intense lysozyme overexpression (+++) was found in 9.5% of the hyperplastic polyps, in 97.6% of the tubular adenomas, in 88.9% of the serrated adenomas, in 93.3% of the villous adenomas, in 76.9% of the carcinomas, but in none of the other tissues investigated. Neoplastic colorectal cells may acquire the capacity to produce lysozyme. The presence of that enzyme may not be a haphazard, capricious event in mutated colorectal epithelial cells but part of a more elaborate molecular behavior, not necessarily antibacterial. Recently, it was demonstrated that patients having lysozyme-secreting breast carcinomas were associated with a favorable prognosis. Whether lysozyme expression has any bearing on the biological behavior of colorectal carcinomas remains to be elucidated. Lysozyme overexpression (+++) also occurred in 2 of the 21 hyperplastic polyps, suggesting that intense lysozyme production might herald a possible dysplastic evolution in some hyperplastic polyps.

Adenocarcinoma↗

PubMedDate not supplied

[Microbial inhibitors of lysozyme].

Lysozyme is one of the most important factors of innate immunity, possessing anti-microbial action against a wide range of microorganisms due to cationic nature of protein and, in a lesser degree, due to muramidase activity. In the process of evolution, different mechanisms of lysozyme inhibition, defined as anti-lysozyme activity (ALA), were formed in microorganisms. The usage of the delayed antagonism principle allowed to reveal anti-lysozyme sign in microorganisms of different phylogenetic groups. In the review, data on the occurrence and level of anti-lysozyme activity in pathogens and representatives of normal microflora were presented; findings on nature and genetic determinants of lysozyme inhibitors are given. questions on drug regulation of ALA of the causative agents in infectious diseases and dysbiotic conditions are discussed.

Animals↗

PubMed1990

Immunocytochemical characteristics of perivascular and intratumoral foam cells in neoplasms of neuroectodermal origin with lysozyme, alfa1-antitrypsin, protein S-100 and GFAP.

Investigations were performed to become acquainted with the immunohistochemical features of foam cells localized perivascular and intratumoral in neoplasms of neuroectodermal origin. Antibodies against lysozyme (muramidase) (LO), alfa 1-antitrypsin (AT), protein S-100 and glial fibrillary acid protein (GFAP) were used. A weak or medium intense reaction result has been obtained in the cytoplasm of the foam cells if antibodies against LO, and alfa 1-antitrypsin and almost negative result if antibodies against protein S-100 and GFAP were used. Only very few cells which differ from the foam cells morphologically were very intense stained with primary antibodies against LO and alfa 1-antitrypsin. In accordance with the present views the LO and AT positive cells were recognized as macrophages. The application of macrophage markers did not allow us to ascribe unequivocally the foam cells macrophage-like or histiocyte-like properties. May be that the foam cells in tumors of perivascular and intratumoral localization present another phenotypic defined group of histiocytes, despite their morphological similarity to those cells derived from smooth muscle cells of arterial blood vessels observed in arteriosclerosis.

Astrocytoma↗

PubMed1978

Constitutive and inducible granulocyte-macrophage functions in mouse, rat, and human myeloid leukemia-derived continuous tissue culture lines.

Fourteen continuous tissue culture cell lines derived from mouse, rat, or human granulocyte-macrophage cancers were studied for expression of spontaneous and inducible markers of differentiated cells. Five cell lines (two mouse, two rat, and one human) synthesized myeloperoxidase spontaneously, and a fifth mouse line showed biochemically inducible enzyme. Twelve lines (6 mouse, 3 rat, and 3 human) produced lysozyme (muramidase), and all had detectable beta-glucuronidase. Superoxide generation was detected in one mouse, and three human cell lines following stimulation with phorbol myristate acetate. Maturation to differentiated polymorphonuclear leukocyte or macrophage morphology was induced in 3 cell lines (2 mouse and 1 human) following culture in diffusion chambers in total-body-irradiated rats. In vitro morphological differentiation was inducible in one (mouse) cell line exposed to casein, thioglycolate, or plasma from irradiated rats or mice. These findings indicate that mammalian cell lines derived from granulocyte-macrophage cancers stably express several combinations of differentiation markers. The patterns of expression of these markers did not always correlate with the morphological stage of differentiation.

Animals↗

PubMed1990

[The physicochemical and biochemical characteristics of the cell walls in M+ and M- variants of Streptococcus group A type 29].

The amino acid composition of cell walls and surface proteins, isolated from virulent (M+) and avirulent (M-) streptococcal strains (group A, type 29) has been determined by the method of E. H. Beachey et al. The kinetics of the lysis and proteolysis of streptococcal cell walls with muramidase and protease obtained from Actinomyces levoris and streptolysin has been studied. The constants describing the progress rates of these processes has been determined; their values in case of both lysis and proteolysis are higher in virulent strains than in avirulent ones.

Amino Acids↗

PubMed1990

Synthesis and release of phospholipase A2 by unstimulated human articular chondrocytes.

High activity of proinflammatory, type II phospholipase A2 (PLA2) was found in synovial fluids (SF) in inflammatory arthritis. In search for the sources of this PLA2, we cultured human articular chondrocytes and cartilage explants from healthy, osteoarthritic and rheumatoid joints. All cultures, unstimulated by cytokines, released PLA2 extracellularly. Cultures obtained from the deep layers of the cartilage released more PLA2 than those obtained from the superficial layers. Deep layer explants released 0.38 to 18.16 pmol/min/mg protein PLA2/day, whereas superficial layer explants released 0.39-3.18 pmol/min/mg/day. Chondrocyte cell cultures continuously released PLA2, in the first day 909-46347 pmol/min/(10)6 cells and after 9-26 days of culture 166-2115 pmol/min/10(6) cells. PLA2 released from chondrocytes was calcium dependent and had optimum activity at pH 7.5. Cycloheximide markedly inhibited its release. Chondrocyte cultures also released muramidase (LZM) but there was no correlation between PLA2 and LZM release. It may be concluded that cytokine unstimulated human articular chondrocytes synthesize and release PLA2 extracellularly which is similar to that found in the SF. Thus, chondrocytes may possibly serve as one of the sources of intraarticular PLA2.

Arthritis, Rheumatoid↗

PubMed1975

Purification and characterization of a Streptomyces albus endo-N-acetylmuramidase lytic for group A and other beta haemolytic streptococci.

The purification and characterization of the streptolytic exo-enzyme from the Maxted-McCarty strain of Streptomyces albus is described. This enzyme was shown to be an endo-N-acetylmuramidase with a molecular weight of 10 to 12,000 and optimal activity at pH 8 and 45 degrees C. The enzyme is lytic for streptococci of various groups, Micrococcus lysodeikticus, Staphylococcus aureus, as well as Escherichia coli. It closely resembles the F1 endo-N-acetylmuramidase described by Ghuysen et al. (1966) except for small differences in the products of lysis of streptococcal cell walls and the resistance of Escherichia coli to lysis by the F1 enzyme. Lysates of group A and A variant streptococcal cell walls prepared with purified Streptomyces albus muramidase contained serologically active M protein and C carbohydrate-peptidoglycan complexes. The chemical and immunological characteristics of these enzymmatic products of streptococcal cell walls are reported and their utility as immunologic reagents is described.

Bacterial Proteins↗

PubMed1985

Enzymuria in aminoglycoside-induced kidney damage. Comparative study of gentamicin, amikacin, sisomicin and netilmicin.

Forty-one patients with urinary tract infections were randomly assigned to receive for six days gentamicin, amikacin, sisomicin or netilmicin. The dose for each patient was calculated according to creatinine clearance and lean body mass in order to avoid overdosages. Urinary enzymes (alpha-glucosidase, gamma-glutamyltranspeptidase and muramidase), serum creatinine and creatinine clearance, proteinuria and urinary sediment were evaluated for nephrotoxicity. None of the patients developed nephrotoxicity, but urinary enzymes rose significantly in all. The statistical analysis of enzymuria during the treatment permitted the definition of a rank order of the nephrotoxic potential of the aminoglycosides studied.

Adolescent↗

PubMed1986

Inflammatory fibrous histiocytoma of bone.

An 11-year-old patient with inflammatory fibrous histiocytoma of the iliac bone is presented. In addition to routine histopathological procedures the lesion was studied by enzyme-histochemical and immuno-histochemical methods. The results of acid phosphatase, alpha-naphthyl-acetate esterase and intracytoplasmic muramidase demonstration in tumour cells supported the histiocytic nature of the presented case.

Bone Neoplasms↗

PubMed1985

[The physiological and diagnostic importance of lysozyme in cow's milk].

The enzyme lysozyme (earlier muramidase) is one of the factors of the non-specific defense mechanism of the mammary gland. It represents a regular constituent of milk, which despite its very low content in milk determines the health condition of the udder and its defending ability against infectious agents. Therefore, a review is given on the factors influencing the lysozyme content in bovine milk, its significance for the bactericidal effects of milk, its changes in mastitis and the resulting possibility of its introduction in diagnostic work, and the therapeutical use of milk rich in lysozyme.

Animals↗