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)

Sixteen plant-derived or synthetic coumarins with various hydroxyl and other substitutions were tested for their ability to scavenge alkylperoxyl radicals generated in the aqueous phase by the controlled thermolysis of 2,2'-azo-bis-(2-amidinopropane) dihydrochloride (ABAP). Protection by coumarins against inactivation of lysozyme by the radicals was assayed by measuring the loss of turbidity of suspensions of M. lysodeikticus. Ten of the coumarins were potent scavengers of aqueous peroxyl radicals with activities comparable to n-propyl gallate, desferrioxamine, ferrioxamine and trolox c, yielding IC50 values in the range 21 to 92 micromolar. The presence of 6,7-ortho-dihydroxy functions gave compounds of the greatest potency. Scavenging activity was unrelated to ability to chelate iron ions. The active coumarins are attractive candidates for evaluation as protective agents against disorders in which oxidative stress is implicated.
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PMID:Peroxyl radical scavenging by a series of coumarins. 148 80

Both the immunoglobulins and non-specific antibacterial factors in milk from cows immunized with pathogenic oral bacteria have the potential to influence the oral microflora during passive immunization studies. The first six milks after calving were collected from 2 cows immunized with adjuvant and from 14 cows immunized with adjuvant and heat-killed strains of periodontopathic Actinomyces, Porphyromonas, Prevotella, and Fusobacterium. Analysis of the products from the first to the sixth milks revealed that the protein and lysozyme content decreased approximately 66 and 72%, respectively; the mean specific activity of the enzyme remained relatively constant. In contrast, the mean lactoperoxidase activity increased 2.3-fold in the second milking and increased further in the fourth and sixth milkings. The mean iron-binding activity increased 1.2-fold from the first to the second milkings and then decreased 3.6-fold through the sixth milking. Cows immunized with adjuvant alone showed similar responses. Per unit volume, the milk contained approximately 150 times less lysozyme than whole human saliva obtained from six subjects but higher concentrations of lactoperoxidase and iron-binding components. Purified bovine nonspecific factors prevented the growth of the bacteria used for immunization when bacteria were tested at concentrations similar to those found in saliva and milk. Because bovine nonspecific antibacterial factors could influence both the pathogenic target bacteria and the indigenous microflora in oral passive immunization studies with bovine immunoglobulins, the presence of these proteins should be considered.
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PMID:Nonspecific antibacterial factors in milk from cows immunized with human oral bacterial pathogens. 150 May 76

In gram-negative bacteria, numerous cell functions, including respiration-linked electron transport, have been ascribed to the cytoplasmic membrane. Gram-negative bacteria which use solid substrates (e.g., oxidized manganese or iron) as terminal electron acceptors for anaerobic respiration are presented with a unique problem: they must somehow establish an electron transport link across the outer membrane between large particulate metal oxides and the electron transport chain in the cytoplasmic membrane. When the metal-reducing bacterium Shewanella putrefaciens MR-1 is grown under anaerobic conditions and membrane fractions are purified from cells lysed by an EDTA-lysozyme-polyoxyethylene cetyl ether (Brij 58) protocol, approximately 80% of its membrane-bound cytochromes are localized in its outer membrane. These outer membrane cytochromes could not be dislodged by treatment with chaotropic agents or by increased concentrations of the nonionic detergent Brij 58, suggesting that they are integral membrane proteins. Cytochrome distribution in cells lysed by a French press protocol confirm the localization of cytochromes to the outer membrane of anaerobically grown cells. This novel cytochrome distribution could play a key role in the anaerobic respiratory capabilities of this bacterium, especially in its ability to mediate manganese and iron reduction.
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PMID:Localization of cytochromes to the outer membrane of anaerobically grown Shewanella putrefaciens MR-1. 159

To clarify the characteristics of mucosal and submucosal gastric cysts, five stomal cancers of the remnant stomach, two cancers with a diffuse cystic distribution and three ordinarily resected cancers were used to study mucinous patterns, proliferative cells and humoral defensive factors in the cystic epithelia. Most cysts showed a gastric appearance with relatively dominant ConA III (+) pyloric gland-like features, and were positively stained with high-iron diamine-alcian blue. Although a few cells positive for proliferative cell nuclear antigen (PCNA) were seen in epithelia, cysts generally revealed a low degree of proliferation, less than 2% of epithelial cells being PCNA (+). Cysts were formed from the isthmus or from ordinary glands, and showed an increase of IgA and secretory component in epithelia of the supranuclear, luminal or basolateral region and increased lysozyme (Ly) activity. Some cysts contained cells with strong positivity for Ly which could not be confirmed as Paneth cells by HE staining. Mucosal and submucosal cysts are considered to arise as a reaction to inflammation, and have a tendency to show both gastric and intestinal characteristics.
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PMID:Histopathological study of mucosal and submucosal cysts of stomach. 167 96

Since recognition during the last decade that certain renal carcinogens can initially cause an accumulation of hyaline (protein) droplets in proximal tubules of male rats, it has become appropriate to establish whether this phenomenon of protein overload can also occur in rodent kidneys unrelated to chemical treatment. Kidney tissue from a number of selected rodent studies held in the National Toxicology Program (NTP) or Food and Drug Administration (FDA) archives were evaluated for hyaline droplet accumulation in proximal tubules. The survey concentrated on rats and mice of both sexes bearing hematopoietic tumors, as our preliminary observations had suggested this direction of study. The tissues of 101 Sprague-Dawley, 25 Osborne-Mendel, and 70 Fischer 344 rats and 96 B6C3F1 mice were examined. These animals provided an assortment of tumors including histiocytic sarcoma, lymphocytic lymphoma, mononuclear cell leukemia, and sarcoma. Hyaline droplet accumulation, primarily involving the P2 segment of proximal tubules, was diagnosed in 96% of rats with histiocytic sarcoma (74/77 cases in Sprague-Dawley, 17/18 in Osborne-Mendels, 7/7 in Fischers) and in 55% of B6C3F1 mice with histiocytic sarcoma (18/33 cases). There appeared to be a qualitative correlation between hyaline droplet accumulation and degree of tumor burden. Thus, in cases negative for hyaline droplets, the tumor was often confined to a single location, while increasing involvement of proximal segments beyond P2 occurred with more extensive multi-organ dissemination of the tumor. By immunohistochemistry on 11 cases of rat and 8 cases of mouse histiocytic sarcoma, the protein in hyaline droplets was identified as lysozyme, a known major secretory product of monocytes and macrophages. The hyaline droplets were negative for alpha 1-antitrypsin, alpha 2u-globulin, rat or mouse immunoglobulin, and albumin. More sparsely scattered droplets and granules present in proximal tubules of Fischer rats with mononuclear cell leukemia were negative for lysozyme but positive for either iron or lipofuscin pigment. The study establishes a clear association between renal tubule hyaline droplet and lysozyme accumulation in rats and mice with histiocytic sarcoma. Hyaline droplets secondary to neoplasia should be distinguished from chemically-induced hyaline droplet nephropathy in the male rat involving alpha 2u-globulin.
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PMID:Hyaline droplet accumulation in rodent kidney proximal tubules: an association with histiocytic sarcoma. 172 1

The true nature of Nucleolar Organizer Regions Argyrophilic related proteins (AgNORs) is still unknown, but there is wide agreement that their number expresses the nuclear activity. We undertook an investigation on fifty cases of gastric adenocarcinomas (previously grouped morphologically into well and poorly differentiated) applying together with the AgNOR technique, histochemical (Alcian Blue/PAS, High Iron Diamine) and immunohistochemical methods (alpha-1-antitrypsin, alpha-1-antichymotrypsin and lysozyme). AB/PAS was more frequently positive in well-differentiated adenocarcinomas. On the contrary HID was prevailingly positive in poorly differentiated adenocarcinomas. alpha 1 ACT was expressed in all poorly differentiated adenocarcinomas and in a few well-differentiated adenocarcinomas, whereas lysozyme and alpha 1 AT were never expressed. The AgNORs were more numerous, larger, clumped and irregular in shape in poorly differentiated adenocarcinomas. Considering that alpha 1 ACT reactivity seems to be well correlated with survival and given that there is a good correlation between the aforementioned characteristics of AgNORs and the expression of alpha 1 ACT, our investigation suggests that the four techniques used in this study could be useful to predict the prognosis.
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PMID:Gastric carcinoma: histopathology, immunocytochemistry and variations of nucleolar organizer regions (AgNORs). 184 Jan 72

Polymorphonuclear leukocytes (PMN) exposed to highly purified human lactoferrin (from colostrum) exhibit an increased random motility (at least 2.5-fold) and are primed to produce more superoxide [12.1 +/- 1.2 nmol O2-/min/10(6) PMN preincubated with lactoferrin (0.5 mg/ml) against 6.4 +/- 2.3 with cells without lactoferrin after FMLP stimulation]. The action of lactoferrin seemed to be specific, because it could be abolished by simultaneous addition of antilactoferrin antibody. Addition of transferrin and iron salts to PMN was without effect. Between iron-poor and iron-saturated lactoferrin there was no difference in influence on PMN function except for a higher FMLP stimulated superoxide production by iron-saturated lactoferrin. Aggregation, degranulation (beta-glucuronidase, lysozyme), and bacterial killing were not influenced by lactoferrin. Incubation of monocytes and monocyte-derived macrophages with lactoferrin did not alter their motility or their superoxide production rates. Our findings indicate that PMN become more effective after exposure to lactoferrin by having a greater motility and producing superoxide at a faster rate.
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PMID:Influence of lactoferrin on the function of human polymorphonuclear leukocytes and monocytes. 184 51

Although lactoferrin has antimicrobial activity, its mechanism of action is not full defined. Recently we have shown that the protein alters the Gram-negative outer membrane. As this membrane protects Gram-negative cells from lysozyme, we have studied whether lactoferrin's membrane effect could enhance the antibacterial activity of lysozyme. We have found that while each protein alone is bacteriostatic, together they can be bactericidal for strains of V. cholerae, S. typhimurium, and E. coli. The bactericidal effect is dose dependent, blocked by iron saturation of lactoferrin, and inhibited by high calcium levels, although lactoferrin does not chelate calcium. Using differing media, the effect of lactoferrin and lysozyme can be partially or completely inhibited; the degree of inhibition correlating with media osmolarity. Transmission electron microscopy shows that E. coli cells exposed to lactoferrin and lysozyme at 40 mOsm become enlarged and hypodense, suggesting killing through osmotic damage. Dialysis chamber studies indicate that bacterial killing requires direct contact with lactoferrin, and work with purified LPS suggests that this relates to direct LPS-binding by the protein. As lactoferrin and lysozyme are present together in high levels in mucosal secretions and neutrophil granules, it is probable that their interaction contributes to host defense.
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PMID:Killing of gram-negative bacteria by lactoferrin and lysozyme. 191 65

Antigen processing involves endocytosis, proteolysis and denaturation of antigens to generate peptides that bind to major histocompatibility complex class II molecules (Ia) in a complex recognized by CD4+ T cells. Ia and antigen are internalized and processed intracellularly, but the exact subcellular site of antigen degradation and formation of the Ia-peptide complex remains unclear. The present studies utilized low-temperature incubation in an attempt to functionally block certain steps in the processing of the antigen hen egg white lysozyme (HEL) by peritoneal exudate cells (PEC) and TA3 B lymphoma cells. Ia endocytosis and uptake of HEL by PEC persisted at 18 degrees C, albeit at somewhat slower rates, but delivery of ligands to lysosomes was blocked. Under these conditions HEL catabolism and antigen processing were effectively blocked, although enough catabolism and antigen processing were effectively blocked, although enough HEL was internalized at 18 degrees C to provide effective presentation during a subsequent incubation at 37 degrees C. In TA3 cells transferrin endocytosis and recycling were notably slowed at 18 degrees C, and iron uptake from transferrin by TA3 cells was completely blocked, indicating that certain specifically endosomal functions were inhibited at 18 degrees C. Thus, intracellular steps in antigen processing were blocked at 18 degrees C, corresponding to deficits in endosomal processing and targeting. These results demonstrate that antigen endocytosis and certain temperature-sensitive endosomal and lysosomal processes are essential for antigen processing.
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PMID:Low-temperature inhibition of antigen processing and iron uptake from transferrin: deficits in endosome functions at 18 degrees C. 196 38

In a previous report from this laboratory (N. J. Laible and G. R. Germaine, Infect. Immun. 48:720-728, 1985), evidence was presented to suggest that the bactericidal actions of both reduced (i.e., muramidase-inactive) human placental lysozyme and the synthetic cationic homopolymer poly-D-lysine involved the activation of a bacterial endogenous activity that was inhibitable by N,N',N"-triacetylchitotriose (chitotriose). In the present investigation however, we found that the bactericidal and bacteriolytic action of poly-D-lysine could be prevented only by some commercially available chitotriose preparations and not by others. Analysis by physical and chemical methods failed to distinguish protective chitotriose (CTa) and nonprotective chitotriose (CTi) preparations. CTi and CTa preparations displayed equal capacities to competitively inhibit binding of [3H]chitotriose by immobilized lysozyme and were indistinguishable in their abilities to block the lytic activity of lysozyme against Micrococcus lysodeikticus cells. Elemental analysis revealed significantly higher levels of phosphorus, calcium, iron, sodium, manganese, and copper in CTa. Removal of metals from CTa by chelate chromatography completely abolished the poly-D-lysine-protective capacity. Of the metals detected, only ferric iron (5 to 10 microM) mimicked the protective action of CTa. A Fe(III) concentration of 50 microM was required to inhibit lysozyme (5 micrograms/ml). Both Fe(III) and CTa (but not CTi) quantitatively blocked the labeling of poly-D-lysine by fluorescamine, suggesting that the primary amino groups of the lysine residues participate in iron binding. Thus, it appears that the poly-D-lysine-protective capacity of certain chitotriose preparations was due not to the chitotriose itself but to contaminating metal ions which interact directly with the polycationic agent. In contrast, Fe(III) cannot account for inhibition of either the bactericidal or bacteriolytic activity of lysozyme by chitotriose.
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PMID:Inhibition of bactericidal and bacteriolytic activities of poly-D-lysine and lysozyme by chitotriose and ferric iron. 198 82


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