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)

The virulence plasmid pYVe of Yersinia enterocolitica codes for the production of the outer membrane protein YadA and the secretion of several proteins, called Yops, which may protect this bacterium against killing by human granulocytes. Granulocytes kill ingested microorganisms by oxygen-dependent and oxygen-independent mechanisms, the latter including antimicrobial polypeptides. The aim of this study was to determine whether virulent (pYVe+) Y. enterocolitica and plasmid-cured avirulent (pYVe-) Y. enterocolitica differ in susceptibility to antimicrobial polypeptides extracted from granules of human granulocytes. The acetic acid granule extract contained several polypeptides with antimicrobial activity against Y. enterocolitica as determined by gel overlay and radial diffusion assays. Two of these polypeptides were identified as lysozyme and defensins. pYVe+ Y. enterocolitica was less susceptible than pYVe- Y. enterocolitica to the antimicrobial activity of granule extract, lysozyme, and defensins as determined in a suspension assay, which indicated that the pYVe plasmid mediates a reduced susceptibility to these polypeptides. The role of YadA in the resistance to antimicrobial polypeptides was analyzed by using mutants of Y. enterocolitica that specifically lack or express YadA. The results demonstrated that YadA conferred resistance to the killing of Y. enterocolitica by the granule extract. Together, these results indicate that the plasmid-encoded factor YadA contributes to the resistance of Y. enterocolitica to the killing by antimicrobial polypeptides of human granulocytes.
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PMID:Role of YadA in resistance to killing of Yersinia enterocolitica by antimicrobial polypeptides of human granulocytes. 861 74

Pesticin of Yersinia pestis is the only bacteriocin that converts sensitive cells to stable spheroplasts. The amino acid sequence of pesticin as derived from the nucleotide sequence shows no similarity to those of any of the bacteriocins. The unique properties of pesticin prompted an investigation of its mode of action. Since the pesticin plasmid does not encode a lysis protein for release of pesticin into the culture medium, pesticin was isolated from cells and purified to electrophoretic homogeneity. Highly purified pesticin degraded murein and murein glycan strands lacking the peptide side chains to products that were similar to those obtained by lysozyme, as revealed by high-resolution high-pressure liquid chromatography. After reduction of the murein degradation products with tritium-labeled sodium borohydride, acid hydrolysis, and separation of the products by thin-layer chromatography, radiolabeled muraminitol was identified. This indicates that pesticin is a muramidase, and not an N-acetyl-glucosaminidase, that converts cells into stable spheroplasts by slowly degrading murein.
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PMID:Pesticin displays muramidase activity. 904 16

The action of bactericidal polycationic peptides was compared in Yersinia spp. by testing peptide binding to live cells and changes in outer membrane (OM) morphology and permeability. Moreover, polycation interaction with LPS was studied by measuring the dependence of dansylcadaverine displacement and zeta potential on polycation concentration. When growth at 37 degrees C, Yersinia pestis and Yersinia pseudotuberculosis bound less polymyxin B (PMB) than pathogenic or non-pathogenic Yersinia enterocolitica, regardless of virulence plasmid expression. Y. pseudotuberculosis OMs were unharmed by PMB concentrations causing extensive OM blebbing in Y. enterocolitica. The permeability to lysozyme caused by PMB was greater in Y. enterocolitica than in Y. pseudotuberculosis or Y. pestis and differences increased at 37 degrees C. Similar observations were made with other polycations using a polymyxin/novobiocin permeability assay. With LPS of cells grown at 26 degrees C, polycation binding was highest for Y. pseudotuberculosis and lowest for Y. pestis, with Y. enterocolitica yielding intermediate results which were lower for pathogenic than for non-pathogenic strains. With LPS of cells grown at 37 degrees C, polycation binding remained unchanged for Y. pestis and pathogenic Y. enterocolitica, increased for non-pathogenic Y. enterocolitica and decreased for Y. pseudotuberculosis to Y. pestis levels. Polycation binding related in part to differences in charge density (zeta potential) of LPS aggregates, suggesting similar effects at bacterial surfaces. It is suggested that species and temperature differences in polycation resistance relate to infection route, invasiveness and intracellular multiplication of Yersinia spp.
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PMID:Yersinia pseudotuberculosis and Yersinia pestis are more resistant to bactericidal cationic peptides than Yersinia enterocolitica. 963 21

In the range of 4-20 degrees C, growth temperature did not influence the heat resistance at 54-66 degrees C for Yersinia enterocolitica at pH 7 in citrate phosphate buffer. However, when cells were grown at 37 degrees C. the D62 increased from 0.044 to 0.17 min. This increase was constant at all heating temperatures tested (z = 5.7-5.8). Growth temperature did not influence the proportion of heat-damaged cells after a heat treatment, as measured by their response to a 2% of sodium chloride added to the recovery medium. The sensitivity of heat treated cells to nisin or lysozyme depended on growth temperature: Whereas the number of cells grown at 4 degrees C surviving heat treatment was the same regardless of the presence of 100 IU/ml of nisin or 100 microg/ml of lysozyme in the recovery medium, that of cells grown at 37 degrees C was, in these media, lower. The pH of maximum heat resistance in citrate phosphate buffer was pH 7 for cells grown at 37 degrees C, but pH 5 for those grown at 4 degrees C. In both suspensions the magnitude of the effect of pH on heat resistance was constant at all heating temperatures. For cells grown at 4 degrees C the heat resistance at 54-66 degrees C, in skimmed milk or pH 7 buffer, was the same. For cells grown at 37 degrees C this also applied for heat treatment at 66 degrees C but at 56 degrees C the heat resistance in skimmed milk was higher.
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PMID:Heat resistance of Yersinia enterocolitica grown at different temperatures and heated in different media. 1035 74

Bacteriophage phiYeO3-12 is a T7/T3-related lytic phage that naturally infects Yersinia enterocolitica serotype O:3 strains by using the lipopolysaccharide O polysaccharide (O antigen) as its receptor. The phage genome is a 39,600-bp-long linear, double-stranded DNA molecule that contains 58 genes. The roles of many of the genes are currently unknown. To identify nonessential genes, the isolated phage DNA was subjected to MuA transposase-catalyzed in vitro transposon insertion mutagenesis with a lacZ' gene-containing reporter transposon. Following electroporation into Escherichia coli DH10B and subsequent infection of E. coli JM109/pAY100, a strain that expresses the Y. enterocolitica O:3 O antigen on its surface, mutant phage clones were identified by their beta-galactosidase activity, manifested as a blue color on indicator plates. Transposon insertions were mapped in a total of 11 genes located in the early and middle regions of the phage genome. All of the mutants had efficiencies of plating (EOPs) and fitnesses identical to those of the wild-type phage when grown on E. coli JM109/pAY100. However, certain mutants exhibited altered phenotypes when grown on Y. enterocolitica O:3. Transposon insertions in genes 0.3 to 0.7 decreased the EOP on Y. enterocolitica O:3, while the corresponding deletions did not, suggesting that the low EOP was not caused by inactivation of the genes per se. Instead, it was shown that in these mutants the low EOP was due to the delayed expression of gene 1, coding for RNA polymerase. On the other hand, inactivation of gene 1.3 or 3.5 by either transposon insertion or deletion decreased phage fitness when grown on Y. enterocolitica. These results indicate that phiYeO3-12 has adapted to utilize Y. enterocolitica as its host and that these adaptations include the products of genes 1.3 and 3.5, DNA ligase and lysozyme, respectively.
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PMID:Nonessential genes of phage phiYeO3-12 include genes involved in adaptation to growth on Yersinia enterocolitica serotype O:3. 1568 5

The antibacterial working range of six lysozymes was tested under ambient and high pressure, on a panel of five gram-positive (Enterococcus faecalis, Bacillus subtilis, Listeria innocua, Staphylococcus aureus and Micrococcus lysodeikticus) and five gram-negative bacteria (Yersinia enterocolitica, Shigella flexneri, Escherichia coli O157:H7, Pseudomonas aeruginosa and Salmonella typhimurium). The lysozymes included two that are commercially available (hen egg white lysozyme or HEWL, and mutanolysin from Streptomyces globisporus or M1L), and four that were chromatographically purified (bacteriophage lambda lysozyme or LaL, bacteriophage T4 lysozyme or T4L, goose egg white lysozyme or GEWL, and cauliflower lysozyme or CFL). T4L, LaL and GEWL were highly pure as evaluated by silver staining of SDS-PAGE gels and zymogram analysis while CFL was only partially pure. At ambient pressure each gram-positive test organism displayed a specific pattern of sensitivity to the six lysozymes, but none of the gram-negative bacteria was sensitive to any of the lysozymes. High pressure treatment (130-300 MPa, 25 degrees C, 15 min) sensitised several gram-positive and gram-negative bacteria for one or more lysozymes. M. lysodeikticus and P. aeruginosa became sensitive to all lysozymes under high pressure, S. typhimurium remained completely insensitive to all lysozymes, and the other bacteria showed sensitisation to some of the lysozymes. The possible applications of the different lysozymes as biopreservatives, and the possible reasons for the observed differences in bactericidal specificity are discussed.
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PMID:Comparison of bactericidal activity of six lysozymes at atmospheric pressure and under high hydrostatic pressure. 1648 12

Carnobacterium maltaromaticum B26 and Carnobacterium divergens B33, which were isolated from the intestine of healthy rainbow trout (Oncorhynchus mykiss, Walbaum), were selected as being potentially useful as probiotics with effectiveness against Aeromonas salmonicida and Yersinia ruckeri. Thus, rainbow trout administered with feed supplemented with B26 or B33 dosed at >10(7) cells g(-1) feed conferred protection against challenge with virulent cultures of the pathogens. Moreover, both cultures persisted in the gut for up to 3 weeks after administration. The cultures enhanced the cellular and humoral immune responses. Specifically, fish fed with B26 demonstrated significantly increased phagocytic activity of the head kidney macrophages, whereas the use of B33 led to significant increases in respiratory burst and serum lysozyme activity. Also, the gut mucosal lysozyme activity for fish fed with both cultures was statistically higher than the controls.
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PMID:Innate immune responses in rainbow trout (Oncorhynchus mykiss, Walbaum) induced by probiotics. 1663 79

The effect of hen egg white lysozyme (HEWL) and bacteriophage lambda lysozyme (LaL) in combination with high pressure (HP) treatment on the inactivation of four gram-negative bacteria (Escherichia coli O157:H7, Shigella flexneri, Yersinia enterocolitica and Salmonella typhimurium), was studied in skim milk (pH 6.8; a(w) 0.997) and in banana juice (pH 3.8; a(w) 0.971). In the absence of lysozymes, S. flexneri was more sensitive to HP in milk than in banana juice, while the opposite was observed for the other three bacteria. In combination with HP treatment, LaL was more effective than HEWL on all bacteria in both milk and banana juice. Depending on the bacteria, inactivation levels in banana juice were increased from 0.4-2.7 log units by HP treatment alone to 3.6-6.5 log units in the presence of 224 U/ml LaL. Bacterial inactivation in milk was also enhanced by LaL but only by 0.5-2.1 log units. Under the experimental conditions used, LaL was more effective in banana juice than in milk, while the effectiveness of HEWL under the same conditions was not significantly affected by the food matrix. This effect could be ascribed to the low pH of the banana juice since LaL was also more effective on E. coli in buffer at pH 3.8 than at pH 6.8. Since neither LaL nor HEWL are enzymatically active at pH 3.8, we analysed bacterial lysis after HP treatment in the presence of these enzymes, and found that inactivation proceeds through a non-lytic mechanism at pH 3.8 and a lytic mechanism at pH 6.8. Based on these results, LaL may offer interesting perspectives for use as an extra hurdle in high pressure food preservation.
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PMID:Inactivation of gram-negative bacteria in milk and banana juice by hen egg white and lambda lysozyme under high hydrostatic pressure. 1684 61

JB-1 and GC2, which were equated with Bacillus sp. and Aeromonas sobria respectively, were recovered from the digestive tract of rainbow trout, Oncorhynchus mykiss and ghost carp, Cyprinus sp. respectively, and demonstrated effectiveness as probiotics for the control of infections caused by Aeromonas salmonicida, Lactococcus garvieae, Streptococcus iniae, Vibrio anguillarum, Vibrio ordalii and Yersinia ruckeri. When administered to rainbow trout (average weight = 12 g) for 14 days in feed dosed at 2 x 10(8) cells g(-1) of feed, JB-1 led to a reduction in mortalities to 0-13% after challenge with a range of bacterial pathogens compared to 80-100% mortalities of the controls. Similarly, use of GC2 reduced mortalities to 0-16% following the challenge compared to 80-100% mortalities of the controls. The mode of action reflected nutrition, production of inhibitory substances and stimulation of the innate immune responses. Specifically, JB-1 and especially GC2 were positive for siderophore and chitinase production, and increased lysozyme, phagocytic and respiratory burst activity.
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PMID:The development of probiotics for the control of multiple bacterial diseases of rainbow trout, Oncorhynchus mykiss (Walbaum). 1785 May 73

Strain NRRL B-30745, isolated from chicken ceca and identified as Enterococcus durans, Enterococcus faecium, or Enterococcus hirae, was initially identified as antagonistic to Campylobacter jejuni. The isolate produced a 5,362-Da bacteriocin (enterocin) that inhibits the growth of Salmonella enterica serovar Enteritidis, S. enterica serovar Choleraesuis, S. enterica serovar Typhimurium, S. enterica serovar Gallinarum, Escherichia coli O157:H7, Yersinia enterocolitica, Citrobacter freundii, Klebsiella pneumoniae, Shigella dysenteriae, Pseudomonas aeruginosa, Proteus mirabilis, Morganella morganii, Staphylococcus aureus, Staphylococcus epidermidis, Listeria monocytogenes, Campylobacter jejuni, and 20 other Campylobacter species isolates. The enterocin, E-760, was isolated and purified by cation-exchange and hydrophobic-interaction chromatographies. The proteinaceous nature of purified enterocin E-760 was demonstrated upon treatment with various proteolytic enzymes. Specifically, the antimicrobial peptide was found to be sensitive to beta-chymotrypsin, proteinase K, and papain, while it was resistant to lysozyme and lipase. The enterocin demonstrated thermostability by retaining activity after 5 min at 100 degrees C and was stable at pH values between 5.0 and 8.7. However, activity was lost below pH 3.0 and above pH 9.5. Administration of enterocin E-760-treated feed significantly (P < 0.05) reduced the colonization of young broiler chicks experimentally challenged and colonized with two strains of C. jejuni by more than 8 log(10) CFU. Enterocin E-760 also significantly (P < 0.05) reduced the colonization of naturally acquired Campylobacter species in market age broiler chickens when administered in treated feed 4 days prior to analysis.
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PMID:Isolation and purification of enterocin E-760 with broad antimicrobial activity against gram-positive and gram-negative bacteria. 1808 39


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