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)

Ampicillin, fusidic acid, gentamicin, imipenem, mezlocillin, ofloxacin, penicillin G, piperacillin, and vancomycin were examined for inhibitory and bactericidal activity in various broth media against 7 clinical isolates of Streptococcus faecalis. On a weight-for-weight basis, ampicillin, imipenem, mezlocillin, and ofloxacin proved to be more efficacious. All enterococcal isolates were resistant against gentamicin; fusidic acid and vancomycin lacked bactericidal activity. The combinations of either ampicillin, imipenem, mezlocillin, ofloxacin, piperacillin, or vancomycin with a subinhibitory concentration (4 micrograms/ml) of gentamicin, with or without added 65% (v/v) fresh defibrinated human blood, respectively, yielded additive effects against all enterococcal isolates. The addition of fresh human blood failed to enhance the antienterococcal activity of 4 micrograms/ml of gentamicin; in contrast, addition of 65% (v/v) fresh or heat-inactivated (56 degrees C, 30 min) normal rabbit, bovine, and human sera augmented the activity of gentamicin, an effect that was ablated through the addition of either 0.005 M DTT or 0.01 M MgCl2 + 0.01 M EGTA + 0.01 M CaCl2, supplements known to antagonize human serum beta-lysin, but not lysozyme activity.
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PMID:Streptococcus faecalis: in vitro susceptibility to antimicrobial drugs, single and combined, with and without defibrinated human blood. 308 51

The conditions for the efficient polyethylene glycol (PEG)-induced spheroplast transformation of three strains of Streptococcus thermophilus have been established. This required the careful optimization of various experimental parameters, the most important being the choice of the lytic enzyme (lysozyme versus mutanolysin), the extent of cell wall digestion and the conditions for the PEG shock which were found to be strain-specific. The transfection assay we had previously developed for S. thermophilus represented a key step and powerful tool in our transformation studies. It allowed individual and stepwise adjustment of the above mentioned factors, but was also compulsory for the establishment of an effective regeneration medium for the strains we examined. Among various potential osmotic protectors tested, raffinose in combination with CaCl2 and MgCl2 was most efficient and routinely supported regeneration with up to 10% efficiency, after PEG treatment. With the spheroplast transformation procedure described in this paper, shuttle vectors and recombinant plasmids could be introduced into three industrial yogurt starters, with maximal efficiencies of 7.5 x 10(4) transformants/micrograms of liposome encapsulated, covalently closed circular DNA. A striking, yet unexplained, reduction in transformation rates was observed when erythromycin rather than chloramphenicol was used as the selecting agent.
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PMID:Development of an efficient spheroplast transformation procedure for S. thermophilus: the use of transfection to define a regeneration medium. 313 74

Lysozyme release from purified human polymorphonuclear leukocytes was found to be uniquely enhanced by 2.5-20 mM LiCl. This effect was dose dependent and was not detected when the media was supplemented with NaCl, KCl, MgCl2, or CaCl2. The purified isotopes of Li+, 6Li, and 7Li were equally effective in enhancing lysozyme release from the cells at 10 and 20 mM, but 6Li was more effective than 7Li at 5 mM. The enhancement of enzyme release in the presence of Li+ was comparable to the enhancement observed in the presence of N-formylmethionylleucylphenylalanine (fMLP). Addition of LiCl plus fMLP did not result in lysozyme release in excess of each stimulant alone, except when the cells were incubated with 20 mM 6Li + 10(-5) M fMLP. In addition, enzyme release induced by these two agents could be further enhanced to the same degree by addition of cytochalasin D to the incubation mixtures. While similarities between enzyme release induced by LiCl and fMLP were detected, optimal stimulation of enzyme release by Li+ was much more sensitive to inhibition by pertussis toxin than was maximal fMLP stimulation. Therefore, the intracellular events altered by Li+ and the peptide may share some metabolic steps, but they differ in their sensitivity to alterations in cAMP metabolism.
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PMID:Characterization of lithium-induced enzyme release from human polymorphonuclear leukocytes. 377 61

Drug-induced nephrotoxicity (NT) has become an increasingly significant clinical problem. An in vitro model of drug-induced NT was therefore developed using gentamicin and the effects of ATP-MgCl2 on reduction or prevention of NT were determined. To study this, non-pulsatile perfusion in isolated rat kidneys was maintained at 100 mm Hg during 2 hr of perfusion at 37 degrees C. The oxygenated Krebs-HCO3 perfusate contained 7.5 g/dl albumin as colloid, glucose, creatinine, amino acids, trace amounts of [3H]inulin and 125I-lysozyme, and either 0, 0.4, 0.8, or 1.2 mg/ml of gentamicin. In some studies, 2 mM ATP-MgCl2 was added with 0.8 mg/ml of gentamicin at 0 and 60 min of perfusion. During each 10-min clearance period, glomerular filtration rates, sodium absorption, water absorption, and fractional clearance of TCA-precipitable lysozyme were measured. The results indicate that renal perfusate flow, glomerular filtration rate, urinary flow and tubular absorption of protein (a sensitive indicator of tubular function), sodium, and water were affected by gentamicin in a dose-dependent manner. An isolated kidney preparation can therefore be used to study gentamicin-induced NT. Higher in vitro perfusate concentrations of the drug were needed, however, to acutely mimic the in vivo cumulative effects. Nonetheless, renal perfusate flow, glomerular filtration rate, and the depression in protein reabsorption which occurred with gentamicin treatment were markedly improved by simultaneous treatment with ATP-MgCl2. Thus, ATP-MgCl2 may be useful in reducing drug-induced nephrotoxicity.
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PMID:Reduction of the drug-induced nephrotoxicity by ATP-MgCl2. II. Effects on gentamicin-treated isolated perfused kidneys. 387 64

Xanthomonas oryzae was shown to contain a constitutive alkaline phosphatase (EC 3.1.3.1.). The enzyme was detectable in intact cells and releasable by osmotic shock or spheroplast formation indicating its periplasmic location in the cell. Sonication released about 85% of the total enzyme, and the releasable amount was increased to 97% when lysozyme was added to the sonicated cells prior to centrifugation. These changes suggest an association of the enzyme with peptidoglycan; the enzyme is not released unless the polymer is digested to small units. Adapted usual method of spheroplast formation released 85%, while modified osmotic shock procedure released about 75% of the enzyme. These procedures released decreased amounts of the enzyme following cell growth reflecting that some changes were taking place toward a tighter association between the enzyme and the cell envelope during aging of the culture. During osmotic shock, the major portion of the released enzyme distributed in supernatant of the first stage (S1) hypertonic solution. The enzyme was inhibited by EDTA, whereas the inhibition was partially removed by dialysis and completely reversed by addition of MgCl2. Data obtained also indicated that X. oryzae seems to have relatively high content of periplasmic protein.
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PMID:Release of alkaline phosphatase from cells of Xanthomonas oryzae by manipulation of surface permeability. 679 31

A simple procedure for the selective isolation of the protective species-specific protein antigens (SPAs) of Rickettsia typhi and Rickettsia prowazekii was developed to permit use of the SPAs in the immunodiagnosis and immunoprophylaxis of typhus infections. Although the SPAs were readily extracted from lysozyme- or detergent-treated rickettsiae, as measured by rocket immunoelectrophoresis, other polypeptides were also present, as shown by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. In contrast, both water and seven buffers, each at a 10 mM concentration and pH 7.6, were nearly equally effective in the selective release of the SPAs from whole cells by extraction for 30 min at 45 degrees C. High-ionic-strength buffers and MgCl2 abolished this SPA release, thus suggesting that divalent cations were important in the binding of the SPAs to the cell envelope. The efficacy of the dilute buffer extraction procedure for isolation of large amounts of SPAs was tested by further characterization of the supernatants obtained by centrifugation (200,000 x g) of two successive tris-(hydroxymethyl)aminomethane-hydrochloride buffer (Tris) extracts. With this procedure, between 10 and 15 mg of SPA was obtained from 100 mg of purified rickettsiae. Although low-molecular-weight ribonucleic acid fragments were released into the Tris extracts in significant amounts, only the SPAs were detected, in significant quantities, as measured by polyacrylamide gel electrophoresis and rocket immunoelectrophoresis. The Tris extracts contained the same major and minor SPA polypeptides as those observed previously in SPA preparations obtained by extensive diethylaminoethyl-cellulose column chromatography, but the Tris SPAs were more satisfactory antigens in an enzyme-linked immunosorbent assay.
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PMID:Isolation of species-specific protein antigens of Rickettsia typhi and Rickettsia prowazekii for immunodiagnosis and immunoprophylaxis. 679 20

Polymyxin-resistant pmrA mutants of Salmonella typhimurium differed from their parents in that they were resistant to tris(hydroxymethyl)aminomethane-ethylenediaminetetraacetate-lysozyme, tris(hydroxymethyl)aminomethane-ethylenediaminetetraacetate-deoxycholate, and tris(hydroxymethyl)aminomethane-ethylenediaminetetraacetate-bacitracin. Tris(hydroxymethyl)aminomethane-ethylenediaminetetraacetate released about 50% less lipopolysaccharide from the pmrA strains than from the parental strains when the bacteria were grown in L-broth containing 2 mM Ca2+. Protamine, polylysine, octapeptin, benzalkonium chloride, cold NaCl, cold MgCl2, or cold tris(hydroxymethyl)aminomethane hydrochloride (pH 7.2) caused no leakage or markedly less leakage of periplasmic beta-lactamase from a pmrA mutant than from its parent strain. pmrA mutants were more resistant than their parent strains to protamine and polylysine but not to octapeptin or benzalkonium chloride, as measured by the ability of these agents to kill the bacteria or to sensitize them to deoxycholate-induced lysis. The pmrA strains did not differ from their parent strains in sensitivity to several antibiotics, in porin function (as measured by cephaloridine diffusion across the outer membrane), or in outer membrane-associated phospholipase A activity.
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PMID:Increased outer membrane resistance to ethylenediaminetetraacetate and cations in novel lipid A mutants. 679 77

The N-acetylglutamate deacetylase (EC 3.5.1.-) from Pseudomonas aeruginosa, strain PAO1, was purified 15,000-fold to electrophoretic homogeneity. The enzyme was distinct from acetylornithinase and formylglutamate hydrolase. Its molecular weight was estimated to be 90,000 by gel filtration and by sedimentation in sucrose gradients. Electrophoresis in sodium-dodecyl sulphate gels gave a single band corresponding to a molecular weight of 44,000. N-Acetylglutamate deacetylase was L-specific and showed no peptidase activity. Among 17 N-acetyl-L-amino acids tested as substrates, N-acetyl-L-glutamine, N-acetyl-L-methionine and N-acetylglycine were hydrolysed at 20% of the rate of N-acetyl-L-glutamate whereas other N-acetyl-L-amino acids were deacetylated at a rate of less than 10%. The catalytic activity depended on Co2+. The Km of the enzyme with respect to N-acetylglutamate was 1.43 mM. Preparation of spheroplasts with lysozyme in the presence of 0.2 M-MgCl2 led to the release of 80% of the enzyme activity from the cells, indicating the periplasmic localization of N-acetylglutamate deacetylase. Its localization in the periplasmic space explains the inability of P. aeruginosa argA mutants to grow on N-acetylglutamate, which is utilized by the wild-type as a carbon and nitrogen source.
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PMID:Properties and localization of N-acetylglutamate deacetylase from Pseudomonas aeruginosa. 680 Nov 90

Proteins extracted from wheat germ 60 S ribosomal subunits and rat liver 60 S and 40 S ribosomal subunits with 3 M NH4Cl/75 mM MgCl2 were able to prevent the ricin A chain-mediated inactivation of untreated 80 S rat liver ribosomes. The protection of polyphenylalanine synthetic capability of 80 S ribosomes was saturable and reached 100% protection in the presence of about 20 micrograms of extracted protein using a uniform set of assay conditions. No protection was observed using proteins extracted from wheat germ 40 S subunits or the core fraction of rat liver 60 S subunits or protein extracted from Escherichia coli ribosomes or ribosomal subunits. The conclusion that the protective effect of extracted 60 S subunit proteins was specific, was further strengthened by showing that unrelated proteins such as alpha-lactalbumin, bovine serum albumin and lysozyme, and polypeptides such as polylysine and poly(aspartic acid), also showed no protection. If 80 S ribosomes were first treated with ricin A chain and then incubated with proteins extracted from rat liver 60 S subunits, no protection was observed. Proteins extracted with NH4Cl/MgCl2 from 60 S rat liver subunits were applied to carboxymethylcellulose column equilibrated with 6 M urea. Stepwise elution with increasing concentrations of LiCl resulted in seven fractions. One fraction (D) contained most of the protective factor; one fraction (E) contained a lesser amount of the protective factor. Two-dimensional polyacrylamide gel electrophoresis of fraction D showed the presence of ten proteins. These data are consistent with the idea that the enzymatic target of ricin A chain is protein is nature and that fraction D contains one or more proteins that appear to act as a inhibitor against ricin A chain.
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PMID:Protection of rat liver 80 S ribosomes against ricin A chain inactivation by proteins extracted from rat liver and wheat germ ribosomal subunits with ammonium chloride/magnesium chloride. 728 85

Purified recombinant poly(hydroxyalkanoic acid) (PHA) synthase from Chromatium vinosum (PhaECCv) was used to examine in vitro the specific synthase activity, turnover of R-(-)-3-hydroxybutyryl coenzyme A (3HB-CoA) and poly(3-hydroxybutyric acid) formation under various conditions. The 3HB-CoA consumption was terminated by a reaction-dependent inactivation of the PHA synthase. Salts (MgCl2, CaCl2, NaCl), proteins (bovine serum albumin, lysozyme, phasine) or detergent (Tween 20) increased the 3HB-CoA turnover to 2.5-fold. Specific PHA synthase activity was only partially affected by the added components. In general, a higher concentration of salt often inhibited the activity of PhaECCv without affecting the yield according to 3HB-CoA turnover. NAD+ and NADP+ (2 mM) inhibited PhaECCv completely, whereas NADH and NADPH did not. Macroscopic poly(3HB) granules were formed in vitro if PhaECCv was incubated in the presence of sufficient amounts of 3HB-CoA and if MgCl2 was present. The form and size of the granules synthesized in vitro were affected by the concentration of the PHA synthase protein as well as by bovine serum albumin and the GA24 protein, a poly(3HB)-granule-associated protein of Alcaligenes eutrophus. Scanning electron micrographs from the synthesized granules were obtained. The granules consisted of poly(3HB) that had a molar mass in the range (1-2) x 10(6) g/mol.
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PMID:In vitro biosynthesis of poly(3-hydroxybutyric acid) by using purified poly(hydroxyalkanoic acid) synthase of Chromatium vinosum. 958 Dec 89


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