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 kinetics of the bactericidal activity of 80 vol% of fresh human serum against representative 'delayed serum-sensitive' (DSS) and 'promptly serum-sensitive' (PSS) strains of Serratia marcescens were further examined with regard to various chemical and absorption procedures known to affect various components of the alternative and classical pathways of human complement activation. Inulin treatment of fresh human serum failed to diminish serum bactericidal activity against DSS and PSS assay strains. Fresh human serum that had been depleted of properdin (factor P) through absorption with zymosan, was as active as control serum against DSS strains of S. marcescens; however, PSS strains were killed in a 'delayed' fashion. Human serum that had been heat-inactivated at 50 degrees C for minutes (depletion of factor B), no longer killed DSS strains, whereas PSS strains of S. marcescens and the PSS control strain Escherichia coli C were killed in a slightly delayed fashion. Hydrazine-hydrate treatment (inactivation of C3 of the complement system) and exposure of fresh human serum to dithiothreitol completely abolished serum bactericidal activity. Bentonite-absorbed fresh human serum no longer killed DSS strains of S. marcescens; some PSS strains of S. marcescens were killed in a delayed manner, whereas control strain E. coli C was as PSS as before. Addition of Seitz-filtered fresh human serum, that lacked beta-lysin and was deficient in lysozyme, to bentonite-absorbed human serum restored bactericidal activity against DSS and PSS strains of S. marcescens; addition to heat-inactivated or Seitz-filtered, heat-inactivated human serum failed to do so. Therefore, bentonite absorption removed to a heat-labile component from fresh human serum clearly different from beta-lysin and lysozyme. Furthermore, human serum beta-lysin and lysozyme were not required for serum-mediated killing of S. marcescens strains of either serum susceptibility category.
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PMID:Further characterization of "promptly" and "delayed" human serum-sensitive strains of Serratia marcescens. 4 45

The antibacterial activity of purified rabbit lysozyme was kinetically investigated at concentrations comparable to those in normal rabbit serum and plasma serum. The bactericidal capability, lysozyme content, and electrophoretic composition of "purified beta-lysin," fractionated from normal rabbit serum, were also examined. In contrast to the extensive antibacterial activity of dilute normal rabbit serum observed in vitro, rabbit lysozyme was only weakly bactericidal for Bacillus subtilis. Inhibition of lysozyme enzymatic and bactericidal activities in normal rabbit serum by antilysozyme immunoglobulin G slightly reduced the initial rate of killing. The addition of neutralizing antibody or histamine (another lysozyme inhibitor) to partially purified bactericidal serum fractions had no effect on killing kinetics. Increasing the ionic strength of reaction mixtures containing normal serum or partially purified bactericidal fractions to levels which completely inhibited lysozyme activity resulted in stimulation of their respective killing kinetics. The addition of inhibitors to normal rabbit plasma serum completely eliminated its bactericidal activity. With regard to the killing of B. subtilis by rabbit and human blood fractions, these analyses clearly demonstrated that (i) although lysozyme is not a significant antibacterial component of normal rabbit serum, it represents the principal factor in normal rabbit plasma serum; (ii) different primary bactericidal mechanisms which are not detectable by singlepoint analyses operate in the sera of different species; and (iii) purified beta-lysin isolated from normal rabbit serum by the classical procedure is a heterogenous mixture of components.
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PMID:Role of rabbit lysozyme in in vitro serum and plasma serum bactericidal reactions against Bacillus subtilis. 11 89

Normal fresh and heat-inactivated (56 degrees C, 30 min) human sera (80 vol%, i.e., 80% [vol/vol] of a 2-ml assay volume) killed Bacillus subtilis ATCC 6633 cell inocula of 1.5 x 10(4) colony-forming units per ml within 1 to 2 h after exposure. The B. subtilis assay strain proved slightly and reversibly susceptible to 5 mug of egg white lysozyme per ml. Seitz filtration of fresh human serum completely removed beta-lysin activity; significant amounts of serum lysozyme were removed as well, as determined with the bioassay strain Micrococcus lysodeikticus ATCC 4698. However, bactericidal activity of human serum via classical or alternative complement pathway activation remained intact. Addition of 0.01 M dithiothreitol to fresh human serum abolished beta-lysin activity, but not that of serum lysozyme. Chelation of fresh and heat-inactivated human serum with 0.01 M MgCl(2) + 0.01 M ethylene glycol tetraacetic acid, but not with 0.01 M ethylenediaminetetraacetic acid, markedly retarded beta-lysin activity; however, lysozyme activity remained unaffected. Chelation of serum with 0.01 M MgCl(2) + 0.01 M ethylene glycol tetraacetic acid + 0.01 M CaCl(2) completely abrogated beta-lysin activity, but not that of lysozyme. Absorption of human serum with 10 mg of bentonite per ml (10 min, 37 degrees C) completely removed beta-lysin and lysozyme activity, but failed to affect serum bactericidal activity against Escherichia coli control strain C. Reconstitution of 50 vol% of bentonite-absorbed serum with 40 vol% of heat-inactivated human serum restored both beta-lysin and lysozyme activity. Addition of either 63 to 500 mug of sodium polyanetholsulfonate per ml or 63 to 500 mug of sodium amylosulfate per ml to 80 vol% of fresh human serum completely neutralized beta-lysin activity for the entire observation period of 22 h.
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PMID:Neutralization of human serum beta-lysin by sodium polyanetholsulfonate and sodium amylosulfate. 22 18

Fresh, defibrinated human blood (80 vol%, i.e., 80% [vol/vol] of a 2-ml final assay volume) from two healthy adult donors killed "delayed serum-sensitive" (DSS) and "promptly serum-sensitive" (PSS) strains of Serratia marcescens, PSS control strain Escherichia coli C, Bacillus subtilis strain ATCC 6633, and Micrococcus lysodeikticus ATCC 4698 in a kinetic manner comparable to that of fresh human serum (80 vol%). However, heat-inactivated (56 degrees C, 30 min), defibrinated human blood revealed markedly reduced or a total lack of beta-lysin activity against the B. subtilis assay strain. Similarly, lysozyme activity of defibrinated blood was diminished somewhat by heat treatment, as determined with the M. lysodeikticus assay strain. Addition of 500 mug of sodium polyanetholsulfonate (SPS) per ml to 80 vol% of fresh, defibrinated human blood completely neutralized blood bactericidal activity against all assay strains of S. marcescens, E. coli C, and B. subtilis; however, SPS at this concentration failed to abolish lysozyme activity for prolonged periods of incubation. Addition of 500 mug of sodium amylosulfate (SAS) per ml to 80 vol% of fresh defibtinated human blood resulted in protection of cell inocula of DSS strains of S. marcescens only; SAS failed to protect cell inocula of the PSS strains of S. marcescens, E. coli C, B. subtilis, and M. lysodeikticus for extended periods of observation. Based on these data, it is recommended that blood culture specimens that are first drawn into specimen containers (such as Vacutainer tubes or the like) at the patient's bedside, and which contain >/=250 mug of SPS per ml, be diluted into suitable broth media with at least >/=250 mug of SPS per ml by the receiving laboratory within 2 to 4 h after procurement of the specimen. This procedure would ensure continued, adequate neutralization of the specimen's inherent beta-lysin, lysozyme, and complement- and antibody-mediated bactericidal activities.
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PMID:Variable neutralization of several nonspecific antibacterial systems in fresh, defibrinated human blood by sodium polyanetholsulfonate and sodium amylosulfate. 22 19

The external eye is continuously exposed to an environment containing potentially pathogenic microorganisms. One of the mechanisms which protects the eye from infection is the tear layer. We review the current knowledge of those antimicrobial substances known to be present in tears and the role they might play in preventing infection. These substances include lysozyme, lactoferrin, beta-lysin, and the antibody-complement system of proteins.
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PMID:Resistance to infection of the external eye: the role of tears. 38 73

Amnionic fluid (AF) specimens from 40 normal obstetric patients at 14 to 16 weeks' gestation and at 37 to 40 weeks' gestation were found to contain both lysozyme and a bactericidal substance identified as B-lysin. The concentrations of both lysozyme and B-lysin were significantly higher in the AF at 40 weeks' than at 14 weeks' gestation. B-lysin concentration in AF were also found to be significantly higher than in either cord or maternal blood.
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PMID:Identification of a bactericidal factor (B-lysin) in amnionic fluid at 14 and 40 weeks' gestation. 40 64

Small amounts of endotoxin injected intramuscularly into cows induced endotoxin pyrogenic tolerance and an increase in the rate at which the serum killed a strain of Escherichia coli. Most of the difference between normal serum and serum from the endotoxin-tolerant animal was shown to be due to a bentonite-adsorbable factor other than lysozyme or beta-lysin. The antibacterial activity was not completely removed from either type of serum after bentonite adsorption. Electron microscope studies and measurement of the rate of release of radioactively labeled cytoplasmic contents showed that the bentonite-adsorbable factor was important in the final breakdown of the cell membrane and release of cellular contents. The antibacterial system was totally dependent on complement, and the importance of antibodies could not be entirely ruled out because adsorption at O C with homologous cells eliminated the killing activity.
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PMID:Increased antibacterial activity against Escherichia coli in bovine serum after the induction of endotoxin tolerance. 78 Feb 75

An antibacterial factor, identical with or closely related to beta lysin, was measured in human tears, in human aqueous humor, and in fractions of each fluid after an absorption step involving cellulose-asbestos filters. Antibeta lysin was used to help distinguish whether bactericidal activity was due to lysozyme or beta lysin. Beta lysin activity was found in both human tears and aqueous humor in higher amounts than were present in serum; appreciable amounts of lysozyme were found in human tears but not in aqueous humor. Beta lysin is a normal constituent of human tears and aqueous humor and its role in these fluids is that of an antibacterial agent that may also act in concert with lysozyme to destroy bacteria in tears.
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PMID:Identification of a nonlysozymal bactericidal factor (beta lysin) in human tears and aqueous humor. 125 73

Although ampicillin is often only bacteriostatic for Listeria monocytogenes in vitro, serum from ampicillin-treated patients was bactericidal. The bactericidal effect of serum was partly removed by bentonite, Seitz-filtration, and addition of FeCl3, suggesting it is mediated by lysozyme and beta-lysin. Partly purified human beta-lysin plus purified human lysozyme or either protein plus ampicillin were bactericidal for L. monocytogenes. Hen egg white lysozyme was not active. Lysozyme and beta-lysin were not synergistic with tetracycline, trimethoprim/sulfamethoxazole, or chloramphenicol. Thus, lysozyme and beta-lysin may play a role in the natural resistance to L. monocytogenes, and these serum proteins could contribute to the effectiveness of ampicillin in vivo.
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PMID:Synergistic effect of human lysozyme plus ampicillin or beta-lysin on the killing of Listeria monocytogenes. 189 73

Tear samples were collected from 1 eye of each of 40 cows, 27 sheep, 5 goats, and 5 human beings. Additionally, 10 bovine tear samples were pooled and concentrated. Spectrophotometric assays, using Micrococcus lysodeikticus, were performed on each sample to detect lysozyme activity expressed in hen egg lysozyme (HEL) equivalents. Lysozyme activity was not detected in tears of cows, but 158.8 +/- 159.3 mg of HEL/ml was detected in tears of sheep, 220.7 +/- 37.5 mg of HEL/ml in tears of goats, and 216.3 +/- 86.2 mg of HEL/ml in tears of human beings. In pooled bovine tear samples, lysozyme activity was not detected on plate assay and lysozyme protein was not detected on polyacrylamide gel electrophoresis, column chromatography, or immunoelectrophoresis with rabbit anti-bovine tear antibodies. On the basis of these observations, we concluded that the basic ocular protective mechanism in bovine tears is not lysozyme. Other anti-bacterial proteins such as lactoferrin, transferrin, complement, or beta-lysin may, therefore, be of primary importance in protecting the bovine eye.
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PMID:Lysozyme concentrations in the tears of cattle, goats, and sheep. 202 Dec 61


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