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)

In a previous paper we reported the presence of components in human tear fluid that block the interaction of proteins with plastic surfaces, interfering with tear protein ELISA and proposed the term coating inhibiting activity. The purpose of the study presented here was to further analyse these components. Coating inhibitory activity in human reflex tears was analysed by lectin affinity chromatography, using the agarose bound lectin Artocarpus integrifolia agglutinin (Jacalin), gel filtration, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), blotting and Jacalin staining. For coating inhibitory activity assay in experimental tear samples, the binding of the protein Avidin-conjugated horseradish peroxidase to the polystyrene surface of ELISA micro-titer plate wells, preincubated with the experimental tear samples was measured. In addition, tears were incubated with scrapings of the ELISA plates used in the assay and with six different types of contact lenses (two rigid gas permeable and four hydrogel soft contact lenses) for analysis of adsorbed components. Lectin affinity chromatography of tears yielded a Jacalin-binding and a non-Jacalin-binding preparation, both exhibiting coating inhibitory activity but representing chemically different preparations as observed by SDS-PAGE. After performing gel filtration, coating inhibitory activity eluted with similar retention in both preparations. In fractions exhibiting activity, tear proteins of low molecular weight (< 40 kDa) were detected. Among these, two Jacalin-binding glycoproteins were detected; a major component of approximately 28 kDa and a somewhat smaller minor component. All low molecular weight components were also detected on the scrapings, incubated with tears. The possibility that coating inhibitory activity in tears might reside in a component of larger molecular size can however not be excluded. The human tear proteins secretory Immunoglobulin A, lactoferrin and lysozyme are not involved in coating inhibition. On one of the two rigid gas permeable contact lenses incubated with the tears, the 28 kDa glycoprotein was detected. From the data obtained in our study we conclude that coating inhibitory activity in tears seems to be associated with multiple components of low molecular weight.
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PMID:Analysis of human tear fluid components, inhibiting protein adhesion to plastic surfaces. 894 5

In human neutrophils, the chemotactic peptide, N-formyl-L-methionyl-L-leucyl-L-phenalalanine (fMLP), the Ca(2+)-ATPase inhibitor, thapsigargin, and the lectins, concanavalin A (Con A) and mistletoe lectin I (ML I), stimulate the entry of Ca2+ and Na+ with subsequent activation of exocytosis and superoxide anion (O2-) formation. We studied the role of actin in neutrophil activation. The actin filament-disrupting substances, dihydrocytochalasin B (dhCB) and botulinum C2 toxin (C2 toxin) potentiated fMLP- and lectin-stimulated Ca(2+)- and Na+ entry. Lectin-induced Mn2+ entry was enhanced by actin disruption, whereas fMLP-triggered Mn2+ entry was unaffected. dhCB and C2 toxin inhibited fMLP- and lectin-stimulated Ba2+ influx. The actin disrupters also inhibited fMLP- and ML I-induced Sr2+ influx, whereas Con A-stimulated Sr2+ entry was not influenced by dhCB and C2 toxin. Thapsigargin-stimulated cation entry was not altered by actin disruption. DhCB and botulinum C2 toxin potentiated lysozyme release induced by all four stimuli. Con A and ML I per se activated O2- formation only in the presence and not in the absence of dhCB. Con A potentiated the stimulatory effects of ML I on O2- formation in the presence of dhCB and primed neutrophils to respond to ML I in the absence of dhCB. Our data indicate the following: (1) dhCB and C2 toxin uncover the existence of multiple cation entry pathways in neutrophils; (2) actin disruption facilitates exocytosis and O2- formation by enhancement of Ca(2+)- and Na+ entry and by altering the function of proteins involved in activation of secretion and O2- formation; and (3) Con A and ML I, which possess different sugar specificities, activate different signaling pathways in neutrophils.
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PMID:Complex regulation of human neutrophil activation by actin filaments: dihydrocytochalasin B and botulinum C2 toxin uncover the existence of multiple cation entry pathways. 920 Dec 61

To study the secretory products and the proliferation of cells of the human respiratory surface epithelium, we established a miniorgan-culture system of bronchial tissue. Biopsies of large airways were grown on agar-coated dishes immersed in a serum-enriched medium. As determined by light and transmission electron microscopy, between 1 and 3 weeks, the organ cultures were covered by a differentiated epithelium consisting of secretory, ciliated, and basal cells. Immunohistochemistry, using antibodies to mucin and lysozyme, and lectin histochemistry revealed both mucous and serous secretory cells in the epithelium. Cell proliferation was studied in situ using antibodies to proliferating cell nuclear antigen (PCNA) and Ki-67. Whereas at the time of explantation the proliferation was low (2.5+/-1.7% of the epithelial cells were PCNA-positive, 1.7+/-0.6 were Ki-67-positive), at 24 h of cultivation, 30.4+/-5.1% or 25.2+/-4.9% of the epithelial cells were labeled with antibodies to PCNA or Ki-67. After 7 days, the number of dividing cells was low again. The results show that the organ-culture system of human respiratory surface epithelium produces a differentiated epithelium that is useful in the study of secretory processes, differentiation, and proliferation.
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PMID:Secretory cell types and cell proliferation of human bronchial epithelial cells in an organ-culture system. 971 48

Airway mucus hypersecretion is in part a response to infection and inflammation. Pseudomonas aeruginosa infection is nearly universal in advanced cystic fibrosis (CF) lung disease. Mucoid strains of P. aeruginosa produce an exopolysaccharide product called alginate. The purpose of this study was to determine whether P. aeruginosa alginate stimulates secretion from mucous or serous cells in the ferret trachea exposed to alginate at concentrations reported to be present in the CF airway. We used a sandwich enzyme-linked lectin assay (ELLA) to measure mucin secretion and spectrophotometry to measure lysozyme secretion from isolated ferret tracheal segments. Purified Pseudomonas aeruginosa alginate stimulated mucin and lysozyme secretion in a dose-dependent fashion (mucin = +111%: P = 0.003; lysozyme = +20%: P = 0.024 at 200 microg/mL). This stimulated secretion was not due to proteolytic activity, and alginate exposure did not produce ultrastructural damage to the trachea. We conclude that alginate may contribute to mucus hypersecretion and respiratory morbidity associated with P. aeruginosa infection in patients with CF.
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PMID:Pseudomonas aeruginosa alginate is a potent secretagogue in the isolated ferret trachea. 1021 55

The effect of alpha-NeuAc(2-->6)Gal/GalNAc-specific lectin from Sambucus nigra (SNA) on the release of lysozyme from human neutrophils was studied in vitro. Interaction of cells with the lectin was accompanied by dose-dependent release of lysozyme, which was increased in the presence of cytochalasin B. The involvement of intracellular signaling pathways in the lectin-induced degranulation of neutrophils was determined using a panel of specific inhibitors tested at concentrations in the range of 10-100 microM. Aristolochic acid (a phospholipase A2 inhibitor), indomethacin (a cyclooxygenase inhibitor), neomycin sulfate (a phospholipase C inhibitor), trifluoperazine (a calmodulin antagonist/protein kinase C inhibitor), N-ethylmaleimide (a sulfhydryl reagent), and guanosine-5;-O-(2-thiodiphosphate) (a G-protein inhibitor) were found to reduce SNA-induced lysozyme release from neutrophils by 20-45%. The treatment of cells with bisindolylmaleimide (a protein kinase C inhibitor), H-8 (an inhibitor of protein kinases A, C, G and of myosin light chain kinase), PD 98059 (a MAP kinase inhibitor), and (+/-)-methoxyverapamil (a Ca2+-channel blocker) failed to affect the release of lysozyme. These results indicate that only selective intracellular pathways associated with activation of G-proteins and phospholipid metabolism as well as the thiol-dependent signaling systems are apparently involved in the realization of the SNA-induced degranulation response of human neutrophils.
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PMID:Effect of signaling inhibitors on the release of lysozyme from human neutrophils activated by Sambucus nigra agglutinin. 1100 87

An 8-year-old male Tibetan Terrier showed prolonged astasia, complete paralysis, ticlike signs, and seizure and died 2 months after the onset of symptoms. Histopathologically, there was moderate to severe infiltration of pleomorphic histiocytic mononuclear cells bilaterally in the basiarachnoidal and ventricular areas of the brain. The spinal dura mater, arachnoidal space, and leptomeninges were also affected by infiltrative proliferation of these mononuclear cells. The infiltrating cells had the morphologic characteristics of histiocytes but exhibited moderate pleomorphism and atypia, with abundant mitotic figures. With immunohistochemistry and lectin histochemistry, most of the infiltrating cells were positive for lysozyme and lectin RCA-1 and negative for glial fibrillary acid protein, suggesting that they were of monocytic/histiocytic-origin. Positive proliferating cell nuclear antigen immunostaining demonstrated that most nuclei of the histiocytic cells were in the S phase of the cell cycle, consistent with a proliferating population of cells. Based on these findings, the case was diagnosed as diffuse leptomeningeal malignant histiocytosis.
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PMID:Diffuse leptomeningeal malignant histiocytosis in the brain and spinal cord of a Tibetan Terrier. 1128 Mar 79

Mucus hypersecretion is an important characteristic of many airway diseases. Mucin is the major component of mucus, and is secreted from surface goblet cells of the airway epithelium and mucous cells of submucosal glands. Lysozyme is an enzyme secreted by serous cells of airway submucosal glands. We hypothesized that secretagogues acting through different pathways would have different effects on tracheal mucin and lysozyme secretion. We used a sandwich enzyme-linked lectin assay (ELLA) to measure mucin-like glycoprotein secretion and a spectrophotometric method to measure lysozyme secretion from isolated ferret tracheal segments. We evaluated the secretory response to four secretagogues; prostaglandin F(2alpha) (PGF(2alpha)), adenosine triphosphate (ATP), methacholine (MCh), and human neutrophil elastase (HNE). Each agent stimulated mucin and lysozyme secretion. The relative potency was PGF(2alpha)< or =ATP<MCh<HNE for mucin and ATP< or =PGF(2alpha)<MCh<HNE for lysozyme secretion. We showed that there is an anatomic gradient for constitutive and stimulated mucin and lysozyme secretion with the distal tracheal segments secreting more mucin and lysozyme per gram of tissue than the proximal segments. This robust model system can be used to evaluate the regulation of airway mucous and serous cell secretion and to assess the effect of agents that might alter the secretory response. We confirm that on an equimolar basis, HNE is one of the most potent mucus secretagogues.
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PMID:Regulation of secretion from mucous and serous cells in the excised ferret trachea. 1134 43

The two major gram-positive bacterial (GPB) ligands are peptidoglycan (PGN) and lipoteichoic acid (LTA). These polymeric LTA and highly organized PGN contain repeating carbohydrate moieties, which are potential targets for pattern recognition molecules. The major pattern recognition proteins and receptors, which bind GPB, either have a lectin, PGN recognition, collagen or leucine-rich repeat (LRR) domain. The soluble innate immune proteins (IIPs) that bind to PGN and LTA include pulmonary collectins surfactant-associated proteins (SP-) A and D, lectin-like pentraxins C-reactive protein (CRP) and serum amyloid P component (SAP), and sCD14. Membrane-anchored lectin or lectin-like group members include macrophage mannose receptor (MR), complement receptor 3 (CR3, or Mac-1, or integrin CD11b/CD18), scavenger receptor A (SRCL-1), lectin-like oxidized LDL receptor 1 (LOX-1), and GPI-anchored CD14. Although Toll-like receptor (TLR) 2 and 4, and CD14 contain extracellular LRR domains, only TLRs have a cytoplasmic domain for signal transduction. Three of the four recently discovered human PGN recognition proteins (PGRP) have a transmembrane domain, and hence, considered as true receptors for GPB. Since lysozyme is the only known pulmonary enzyme that can lyse bacterial cell wall PGN, other innate immune molecules appear to be responsible for signalling and enhancing the clearance of GPB infection from the lung. Interestingly, pulmonary collectins bind not only to GPB ligands but also to the receptors, CD14 and TLR, and antigen processing cells such as dentritic cells. These complex interactions appear to play major roles in linking innate and adaptive immunity, and maintaining a pathogen-free lung with minimal, or no inflammation.
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PMID:Pulmonary innate immune proteins and receptors that interact with gram-positive bacterial ligands. 1239 17

High-sensitivity isothermal titration calorimetry was used to characterize the binding of the glycohydrolitic enzyme hen egg-white lysozyme to its natural saccharide inhibitors, chitobiose and chitrotriose. Measurements were done at a pH of 4.7, in the 15 degrees C -45 degrees C temperature range. Using a structural-energetic parameterization derived previously for lectin-carbohydrate associations, both binding enthalpies and entropies for the present systems and for the complex of chitobiose with turkey egg-white lysozyme from the literature were correctly accounted for. These observations suggest that both lysozymes and lectins follow the same structural-energetic behavior in the binding to their ligands. From the analysis of lysozyme data in conjunction with other binding data reported in the literature, an ad hoc parameterization of DeltaCp for protein-carbohydrate complexes was derived for the first time. The novel parameters for both polar and apolar surface areas differed significantly from correlations obtained previously from model compounds and protein-folding data. As DeltaCp is extremely sensitive to changes in solvent structure, this finding indicates that protein-carbohydrate complexes have distinctive hydration properties. According to our analysis, the dehydration of polar groups is the major cause for the observed decrease in DeltaCp, which implies that these groups behave hydrophobically. The contribution of apolar surface areas was found of the expected sign, but their specific weight is much smaller than those obtained in other correlations. This small contribution to DeltaCp is consistent with Lemieux's hypothesis of a low degree of hydration of apolar surfaces on carbohydrates.
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PMID:Structural energetics of protein-carbohydrate interactions: Insights derived from the study of lysozyme binding to its natural saccharide inhibitors. 1249 36

The yeast Saccharomyces cerevisiae is widely regarded as being only capable of producing N-linked glycans with high-mannose structures. To investigate the glycan structures made in different mutant strains, we made use of a reporter protein consisting of a version of hen egg lysozyme that contains a single site for N-linked glycosylation. Mass spectrometry analysis of the attached glycans revealed that a large proportion contained an unexpected extra mass corresponding to a single N-acetylhexosamine residue. In addition, the glycosylated lysozyme was recognized by an N-acetylglucosamine specific lectin. The genome of S. cerevisiae contains an uncharacterized open reading frame, YOR320c, that is related to a known N-acetylglucosaminyltransferase. Deletion of this ORF resulted in the disappearance of the extra mass on the N-linked glycans and loss of lectin binding. We show that the protein encoded by YOR320c (which we term Gnt1p) is localized to the Golgi apparatus and has GlcNAc-transferase activity in vitro. The physiological role of Gnt1p is unclear because mutants lacking the protein show no obvious growth or cell wall defects. Nonetheless, these results indicate that heterologous glycoproteins expressed in yeast can receive N-glycans with structures other than high mannose. In addition, they indicate that the lumen of the yeast Golgi contains UDP-GlcNAc, which may facilitate reconstitution of higher eukaryotic N-glycan processing.
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PMID:An N-acetylglucosaminyltransferase of the Golgi apparatus of the yeast Saccharomyces cerevisiae that can modify N-linked glycans. 1265 85


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