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 action of certain substances known to induce cellular alterations, or encounted in the oral cavity, on the accumulation of 18F by Streptococcus mutans GS-5 has been investigated. A 62-67% inhibition in the number of 18F atoms bound per mg dry weight of cells could be induced by a 15 min pretreatment with 2.7 X 10(-4) M cetyltrimethylammoniumbromide, 1 X 10(-1) M acetic anhydride, or 7 X 10(-2) M HCl. Plate counts indicated that alteration of the cellular composition rather than viability was responsible for this diminution in 18F accumulation. Prior exposure for 15 min of this organism to 1 M HCHO or 0.1 M NaOH did not alter 18F accumulation. Of the common salts encountered in the oral cavity, CaCl2 enhanced 18F binding. Pretreatment of the assay cells for 15-160 min with 0.1-10 mg/ml of trypsin, pronase, protease, alpha-glucosidase, dextranase, or lactoferrin had no significant effect on the accumulation of 18F. However, pre-exposure of cells for 60 min to 1-10 mg/ml of either amylase or lipase induced a 40-67% inhibition in the binding of 18F, while lysozyme enhanced the binding of 18F by the cells. It would appear then that the binding of 18F by S. mutans may be altered by certain substances encountered in the oral cavity.
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PMID:The action of selected agents on the accumulation of 18F by Streptococcus mutans. 618 42

The clinical course of giardiasis is variable, and serum antibodies do not appear to be protective. We propose that natural factors either produced by intestinal tissue, transported into the intestine, or ingested (ie, by breast-fed babies) might promote resistance to this disease. Human milk is very rich in secretory IgA (S-IgA) antibodies, as well as nonspecific antibacterial factors (eg, lactoferrin, lysozyme). Previous studies showed that Giardia lamblia trophozoites were killed by nonimmune human milk (NHM) in a time- and concentration-dependent manner. Removal of greater than 99% of the S-IgA from NHM did not decrease its Giardia-cidal activity. Thus, the killing was not antibody dependent. This is the first demonstration of nonimmune antiparasitic defenses in human milk. The present studies show that in the presence of NHM, trophozoites lost motility, swelled, and lysed. The Giardia-cidal activity (GCA) may be specific to human milk, since unheated cow's and goat's milk were virtually devoid of activity. Much, but not all, of the GCA was lost when NHM was heated or reacted with diisopropylfluorophosphate (DIFP), a specific esterase inhibitor. Activity of the major human milk lipase (BSL, bile salt-stimulated lipase, a fatty acid esterase) was lost after heat or DIFP treatment and was absent from cow's or goat's milk. The parasites were also killed by pure BSL. These studies suggest that BSL may be a heat-labile Giardia-cidal component of NHM.
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PMID:Killing of Giardia lamblia trophozoites by normal human milk. 667 55

A variable population of fat-filled "foam" cells in diet-induced experimental arterial intimal plaques of rabbits and monkeys were analyzed for several features characteristic of macrophages. These included: 1) surface binding and phagocytosis of antibody-coated or complement-coated erythrocytes to detect specific surface receptors; 2) cytochemical tests and ultrastructural features to evaluate cell function and structure; and 3) rapid adherence to glass, a feature of macrophage activity, to isolate and identify a homogeneous population of fat-filled foam cells from excised and disrupted arterial lesions. Mixed populations of cells grown in culture from explants of lesions were also analyzed and lipid-filled cells were studied in histologic sections of adjacent lesions. Eighty to ninety percent of the easily dislodged glass-adherent cells from lesions had surface receptors for the Fc portion of immunoglobulin G and for the third component of complement. Coated red blood cells were readily phagocytized, but noncoated cells were not. Acid lipase activity was demonstrated in the Fc-receptor-positive cells. These cells were also devoid of ultrastructural features of smooth muscle. Among the cells growing or migrating out of explants, a population of large round foam cells possessed all of the macrophage features found in the glass-adherent cells from lesions and lacked ultrastructural characteristics of smooth muscle. Fusiform lipid vacuolated cells also grew out of the explants but did not exhibit surface receptors, failed to phagocytize coated or noncoated erythrocytes and did not stain for acid lipase activity; these cells showed distinctive morphologic features of smooth muscle. In histologic sections of nearby lesions foam cells that showed macrophage characteristics, ie, acid lipase activity and the presence of lysozymelike antigen, lacked ultrastructural smooth muscle features. Smooth muscle cells in lesion sections often contained lipid but demonstrated no lysozyme or acid lipase activity. The occurrence of a population of cells with several functional and structural features of macrophages among the lipid-laden cells of experimental diet-induced arterial lesions suggests that some foam cells may be derived from monocytes. An alternative explanation, that metabolically altered autochthonous arterial wall cells assume one or more characteristics of mononuclear phagocytes is less likely, since some of the markers used in these experiments are unrelated. Both explanations deserve further careful study.
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PMID:Arterial foam cells with distinctive immunomorphologic and histochemical features of macrophages. 677 35

Experimental otitis media was produced in chinchillas by eustachian tube obstruction or pneumococcal infection. Sequential changes in the histology of the middle ear mucosa and enzyme profile of the middle ear effusions (MEE) were studied. In serous otitis media (SOM) which followed tubal obstruction, the subepithelial space was widened by edema and capillary dilatation, and the middle ear space was filled with serous fluid. Slight hyperplasia of epithelial cells was also observed. The subepithelial space remained widened with mild fibrous change and capillary dilatation, and slight hyperplasia of epithelial cells persisted 42 days after obstruction. In purulent otitis media (POM), which followed inoculation of pneumococci into the middle ears, metaplasia of the epithelial layer from flat to columnar cells was observed. The subepithelial space was widened with loose fibrous connective tissue proliferation, vascular dilatation and inflammatory cell infiltration. Both lactate dehydrogenase (LDH) and lysozyme levels in MEE were higher in the POM group than in the SOM group. When bacterial enzymes, hyaluronidase and lipase activity were measured in MEE and plotted together with the percentage of positive culture of the MEE at different times after the experimental infection, the enzyme activities decreased with the clearing of bacteria and along with the resorption of inflammatory changes of middle ear mucosa evidenced by histology. In human MEE studies, immunoglobulins (IgG, IgA, IgM) of MEE were higher than in serum except IgM in serous MEE. The IgG content of MEE in the culture-negative group was higher than in the culture-positive group. Possible mechanisms for this difference were discussed.
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PMID:Biochemical and immunochemical characteristics of middle ear effusions in relation to bacteriological findings. 677

The effect of the infection with M. lepraemurium on the activity of several lysosomal enzymes of mouse peritoneal cells was studied. The enzymes studies were acid- and alkaline-phosphatases, acid (cathepsin D-type) proteinase, beta-glucuronidase, deoxyribonuclease, a nonspecific lipase, and lysozyme. Enzyme determinations were carried out four months and six months after the infection with 15.5 X 10(7) bacilli per mouse. Clear differences between M. lepraemurium-infected and normal animals were observed at four months of infection, with all of the mentioned enzyme activities well above the normal values. At six months of infection, a tendency to decrease to normal values of the enzyme activities was observed. It is suggested that this biochemical activation of mouse peritoneal cells reflects the effect of the cell-mediated immune response triggered by the infection with the murine leprosy bacillus. M. lepraemurium-infected mice possess macrophages in a high state of biochemical activation; yet, they are unable to get rid of the infecting microorganism.
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PMID:Phagocytosis in leprosy. 5. The effect of the infection with Mycobacterium lepraemurium on the level of diverse hydrolytic lysosomal enzymes of murine peritoneal macrophages. 689 May 33

An esterase activity hydrolyzing palmitoyl-CoA was released into the culture medium from Mycobacterium smegmatis. Although another esterase activity hydrolyzing Tween 20 (polyoxyethylene sorbitan monolaurate) was also found in the culture medium, the bulk of the esterase activity was retained in the cells. However, treatment of early-log phase cells with lysozyme to prepare ghosts released 80% of the Tween 20 hydrolyzing activity, indicating the localization of the esterase in the periplasmic space or the cell envelope fraction. The presence of two different esterases hydrolyzing palmitoyl-CoA and Tween 20, suggested by the above results, was confirmed by the separation of these esterases on phenyl-Sepharose column chromatography. Palmitoyl-CoA hydrolase (thioesterase) was purified 630-fold from lysozyme-treated supernatant fluid to homogeneity, by means of Sephadex G-100 gel filtration, and DEAE-cellulose, phenyl-Sepharose and Blue-Agarose column chromatographies. Its molecular weight was approximately 42,000. Tween hydrolase was partially purified 150-fold by the same purification procedure up to the step of phenyl-Sepharose chromatography and its molecular weight was found to be about 51,000. These activities were stable against heating at 60 degrees C and treatment with non-ionic detergents. Thioesterase hydrolyzed long chain acyl-CoAs (C12-C20), but not Tween 20-80 or beta-naphthyl acetate. On the other hand, Tween hydrolase hydrolyzed Tween 20-80 and beta-naphthyl acetate. On the other hand, Tween hydrolase hydrolyzed Tween 20-80 and beta-naphthyl acetate, but not acyl-CoAs. Both esterases hydrolyzed monoolein, but not diolein, triolein, or phosphatidylcholine.
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PMID:Two esterases released from Mycobacterium smegmatis from the hydrolysis of long chain acyl-CoAs and Tween. 733 1

Although human milk generally contains higher levels of enzymes than bovine milk, little definitive information is available concerning their role or significance. The enzyme levels in human milk as compared to bovine milk and levels in human colostrum versus normal milk are summarized. The few most widely studied human milk enzymes are discussed in more detail. Evidence is presented to support the views that 1) lipoprotein lipase and ribonuclease are probably spilled into the milk from the blood; 2) lysozyme is spilled from the secretory epithelial cells; 3) lactate and malate dehydrogenases, glucose-6-phosphate dehydrogenase, and lactose synthetase are synthesized in the mammary gland in response to hormonal stimuli; and 4) bile salt stimulated lipase, diastase, protease, and lysozyme are present in sufficient quantities to aid infants in growth and nutrition. Consideration must be given to standardizing the various enzyme assay procedures and activity units so that meaningful comparisons between various studies could be made.
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PMID:Role and significance of enzymes in human milk. 740 88

The growth of group A human, bovine, equine and porcine rotaviruses were enhanced by pretreatment of virus with pancreatin, trypsin, protease, alkaline phosphatase or pepsin and incorporation of these enzymes in maintenance medium. In contrast, alpha-amylase or lipase inhibited the growth of equine and porcine rotaviruses. The other enzymes, adenosine deaminase, lactase, lysozyme, ribonuclease or triose-phosphate isomerase gave little or no change in the growth of all four rotaviruses.
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PMID:Effect of enzymes on the growth of human and animal rotaviruses. 754 24

Xylose-inducible vectors have been constructed for extracellular production of antibody fragments in Staphylococcus carnosus. The pre-pro sequence of S. hyicus lipase was taken as secretional signal sequence, and the S. xylosus Xyl repressor was used to confer xylose inducibility of transcription. Cleavage sites for the IgA protease were engineered between the pre-pro sequence and the antibody fragments to permit removal of the pro sequence. Extracellular expression of the light chain and the Fd fragment of a chimeric Fab fragment containing the variable regions of the anti-lysozyme antibody D1.3 was achieved with these vectors. The pro sequence could be removed from the expression product by IgA protease treatment. When the light chain and the Fd fragment were co-secreted as a protein fusion they accumulated in a structure capable of heterodimerization after IgA cleavage. This fusion contains the pre-pro sequence followed by the light chain, a second IgA site and the Fd fragment.
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PMID:Extracellular expression of native human anti-lysozyme fragments in Staphylococcus carnosus. 760 92

In an earlier report, we had described the isolation and characterization of autolysis-defective mutants of Staphylococcus aureus (N. Mani, P. Tobin, and R.K. Jayaswal, J. Bacteriol. 175:1493-1499, 1993). In the study reported here, an autolysis-defective mutant showed attenuated virulence in a rat model of experimental endocarditis, supporting the role of autolysins in pathogenicity. Transmission electron micrographs of the mutant cells revealed a rough outermost surface as compared with the parent strain, ISP2018. Treatment of mutant cells with lysozyme, proteases, and lipase failed to alter this rough appearance. Physical and genetic data locate the site of mutation between the omega 1100 and ilv loci on the S. aureus chromosome.
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PMID:Autolysis-defective mutant of Staphylococcus aureus: pathological considerations, genetic mapping, and electron microscopic studies. 790 80


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