Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.2.1.31 (beta-glucuronidase)
 7,680 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A substantial production of prostaglandin E2 (PGE2) was induced in primary cultures of rat Kupffer cells by zymosan, calcium ionophore A23187, phorbol ester and arachidonic acid, whereas contact with latex particles, glucan or immunocomplexes led to a minor PGE2 release only. Superoxide generation, on the other hand, was observed after administration of zymosan, glucan and the phorbol ester but not after treatment with the calcium ionophore, arachidonate, latex particles or immunocomplexes. Lysosomal enzymes like beta-glucuronidase and N-acetyl-beta-D-glucosaminidase were detected in the medium of rat Kupffer cells in primary culture after contact with zymosan or calcium ionophore A23187. Other particulate matter, e.g., latex particles, glucan and immunocomplexes, lipopolysaccharides or soluble agents such as phorbol ester, arachidonic acid and gamma-interferon did not provoke the release of lysosomal enzymes. The activities of beta-glucuronidase and N-acetyl-beta-D-glucosaminidase found following prolonged exposure to zymosan or to A23187 were accompanied by the appearance of typical cytosolic enzymes like lactate dehydrogenase and glucose-6-phosphate dehydrogenase in similar proportions and with the same time course. The release of lysosomal enzymes seen after administration of zymosan or calcium ionophore is thought to be the result of unspecific leakage rather than a specific response of elicited Kupffer cells.
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PMID:Release of lysosomal enzymes is not correlated with superoxide and prostaglandin production by stimulated rat Kupffer cells in primary culture. 284 90

Studies were undertaken to elucidate the active component in zymosan necessary to induce the delayed-onset synthesis and secretion of representative lysosomal hydrolases, hexosaminidase, and beta-glucuronidase in macrophages. Resident mouse peritoneal macrophages were challenged with zymosan particles and particulate beta-1,3-glucan, the major subcomponent of zymosan. Zymosan was found to induce a rapid secretion of preformed hexosaminidase with maximal release (75%) occurring 6 hr after the addition of zymosan. By contrast, beta-1,3-glucan was totally inactive in this respect. However, both zymosan and beta-1,3-glucan were found to induce the delayed-onset synthesis and secretion of hexosaminidase and beta-glucuronidase while maintaining constant cellular enzyme levels over a 5-day period following the addition of stimulus. These late responses were almost totally blocked by a noncytolytic concentration of cycloheximide, indicating their dependence on de novo protein synthesis. Mannan, the second major subcomponent of zymosan, had no effect on either immediate secretion or delayed-onset synthesis and secretion of hexosaminidase. These results suggest that the induction of the delayed-onset synthesis and secretion of the lysosomal hydrolases by zymosan may be dependent on the glucan subcomponent of zymosan. Moreover, it would also appear that the release of preformed lysosomal enzymes is not the trigger for the delayed-onset synthesis and secretion of hexosaminidase.
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PMID:Induction of macrophage lysosomal hydrolase synthesis and secretion by beta-1,3-glucan. 294 4

Serum amyloid P component (SAP) is a normal human serum protein with pentraxin structure that has morphological and immunochemical identity to the amyloid P component found in normal tissue and amyloid deposits. In the presence of calcium, SAP binds to certain complex polysaccharides, including agarose and zymosan. While the binding of SAP to agarose involves interaction with a galactose pyruvate acetal, the ligand in zymosan has not been defined. In the present study we determined that SAP binds to ligand(s) in a soluble extract of zymosan prepared by alkaline hydrolysis, which contains the mannose oligosaccharide sequences alpha DMan1----3DMan and alpha DMan1----6DMan. SAP did not bind to the alkali-insoluble fraction of zymosan, which is predominantly a glucan polymer, and its binding to zymosan extract which had been absorbed with concanavalin A was markedly reduced, suggesting that mannose residues are involved in the binding of SAP to zymosan. We also demonstrated that SAP binds to the glycoproteins ovalbumin, thyroglobulin, beta-glucuronidase and C3bi, which contain mannose-terminated sequences, while it did not bind to native and desialized preparations of ovomucoid, alpha 1-acid glycoprotein and glycophorin, which lack terminal mannose residues. SAP did not bind to pneumococcal C polysaccharide or to N-acetylglucosamine oligosaccharides covalently linked to a protein carrier. The binding of SAP to ligand(s) in zymosan extract or ovalbumin was inhibited by the preincubation of SAP with either zymosan extract or ovalbumin glycopeptides, both of which share similar mannose oligosaccharide sequences. All of the SAP binding reactions required calcium, were maximal at approximately 1 mM calcium, and gave similar results whether purified SAP or SAP in serum was used. These findings indicate that mannose-terminated oligosaccharides of polysaccharides and glycoproteins represent a new class of ligands for SAP and suggest that SAP may function as a mannose-binding protein.
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PMID:Evidence that serum amyloid P component binds to mannose-terminated sequences of polysaccharides and glycoproteins. 321 Nov 59

The objective of this study was to investigate the mechanisms that contribute to the generation of macrophage functional diversity. Exposure of mouse bone marrow-derived macrophages to beta-1,3-glucan, a particulate inflammatory stimulus, or polyinosinate-polycytidylate (poly[I:C]), a stimulus of macrophage cytocidal activation, induced distinct and stimulus-specific patterns of gene expression. These changes were characterized by an up-regulation of the expression of the acid hydrolase beta-glucuronidase and platelet-derived growth factor B following incubation with beta-1,3-glucan and a stimulation of the expression of the complement component Bf, beta-interferon, and the reactive nitrogen intermediates NO2/NO3 during incubation with poly[I:C]. The induction of Bf expression by poly[I:C] could not be explained on the basis of distinct subpopulations of cells since in situ hybridization with a mouse Bf cRNA probe revealed a uniform and substantial increase in Bf expression by the entire population of cells. Incubation of macrophages with beta-1,3-glucan before stimulation with poly[I:C] was found to strongly attenuate the expression of Bf and beta-interferon. Conversely, incubation with poly[I:C] prior to exposure to beta-1,3-glucan substantially blocked the stimulation of beta-glucuronidase and platelet-derived growth factor B expression, indicating that these two responses were expressed in a mutually antagonistic fashion. However, after removal of either stimulus and following a period in which the primary response was allowed to decay, the cells regained their capacity to subsequently respond to either the same stimulus or to a different stimulus. Collectively, these findings indicate, first, that the heterogeneity of gene expression seen in response to poly[I:C] represents an adaptive response of the entire macrophage population rather than the restricted responses of distinct subpopulations of cells. Second, macrophages respond to these stimuli in a sequential fashion. These findings thus have a significant bearing on our understanding of the regulation of macrophage heterogeneity in host defense.
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PMID:Development of functional diversity in mouse macrophages. Mutual exclusion of two phenotypic states. 834 4

Polygalacturonase-inhibiting proteins (PGIPs), leucine-rich repeat (LRR) proteins evolutionarily related to several plant resistance genes, bind to and regulate the action of fungal endopolygalacturonases. In Phaseolus vulgaris L., PGIPs are encoded by a gene family comprising at least five members. As a start for a systematic analysis of the regulation of the pgip family, we have analysed the ability of the promoter of the bean gene pgip-1 to direct expression of beta-glucuronidase (GUS) in transfected tobacco protoplasts, microbombarded bean and tobacco leaves, and transgenic tobacco plants. In protoplasts, the pgip-1 gene region from nucleotide (nt) -2004 to nt +27 directed a level of expression that was as high as that directed by the cauliflower mosaic virus (CaMV) 35S promoter and could not be further induced by elicitor treatment; alteration of the region immediately following the TATAA sequence at nt -29 abolished expression. Upon stable integration into tobacco plants of the pgip-1 promoter-GUS construct, as well as of a -394 deletion, expression was detected for both constructs mainly in the stigma and, to a lesser extent, in the anthers and in the conductive vascular tissue. The promoter responded to wounding but not to oligogalacturonides, fungal glucan, salicylic acid, cryptogein, or pathogen infection. This expression pattern does not mirror that of the whole pgip gene family.
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PMID:The promoter of a gene encoding a polygalacturonase-inhibiting protein of Phaseolus vulgaris L. is activated by wounding but not by elicitors or pathogen infection. 963 69

Starch branching enzymes (SBE) which catalyse the formation of alpha-1,6-glucan linkages are of crucial importance for the quantity and quality of starch synthesized in plants. In maize (Zea mays L.), three SBE isoforms (SBEI, IIa and IIb) have been identified and shown to exhibit differential expression patterns. As a first step toward understanding the regulatory mechanisms controlling their expression, we isolated and sequenced a maize genomic DNA (-2190 to +5929) which contains the entire coding region of SBEI (Sbe1) as well as 5'-and 3'-flanking sequences. Using this clone, we established a complete genomic organization of the maize Sbe1 gene. The transcribed region consists of 14 exons and 13 introns, distributed over 5.7kb. A consensus TATA-box and a G-box containing a perfect palindromic sequence, CCACGTGG, were found in the 5'-flanking region. Genomic Southern blot analysis indicated that two Sbe1 genes with divergent 5'-flanking sequences exist in the maize genome, suggesting the possibility that they are differentially regulated. A chimeric construct containing the 5'-flanking region of Sbe1 (-2190 to +27) fused to the beta-glucuronidase gene (pKG101) showed promoter activity after it was introduced into maize endosperm suspension cells by particle bombardment. 1998 Elsevier Science B.V.
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PMID:Genomic organization and promoter activity of the maize starch branching enzyme I gene. 972 5

Accumulated evidence links an important signal involved in glucose-stimulated insulin release to the activation of the islet lysosomal glycogenolytic enzyme acid glucan-1,4-alpha-glucosidase. We have analyzed the function of the lysosomal system/lysosomal enzyme activities in pancreatic islets of young (6-8 weeks), spontaneously diabetic, GK (Goto-Kakizaki) rats and Wistar control rats in relation to glucose-induced insulin release. The insulin secretory response to glucose was markedly impaired in the GK rat, but was restored by the adenylate cyclase activator forskolin. Islet activities of classical lysosomal enzymes, e.g.. acid phosphatase, N-acetyl-beta-D-glucosaminidase, beta-glucuronidase, and cathepsin D, were reduced by 20-35% in the GK rat compared with those in Wistar controls. In contrast, the activities of the lysosomal alpha-glucosidehydrolases, i.e.. acid glucan-1,4-alpha-glucosidase and acid alpha-glucosidase, were increased by 40-50%. Neutral alpha-glucosidase (endoplasmic reticulum) was unaffected. Comparative analysis of liver tissue showed that lysosomal enzyme activities were of the same magnitude in GK and Wistar rats. Notably, in Wistar rats, the activities of acid glucan-1,4-alpha-glucosidase and acid alpha-glucosidase were approximately 15-fold higher in islets than in liver. Other lysosomal enzymes did not display such a difference. Normalization of glycemia in GK rats by phlorizin administered for 9 days did not influence either the lysosomal alpha-glucosidehydrolase activities or other lysosomal enzyme activities in GK islets. Finally, the pseudotetrasaccharide acarbose, which accumulates in the lysosomal system, inhibited acid glucan-1,4-alpha-glucosidase activity in parallel with its inhibitory action on glucose-induced insulin release in intact Wistar islets, whereas no effect was recorded for either parameter in intact GK islets. In contrast, acarbose inhibited the enzyme activity equally in islet homogenates from both GK and Wistar rats, showing that the catalytic activity of the enzyme itself in disrupted cells was unaffected. We propose that dysfunction of the islet lysosomal/vacuolar system is an important defect impairing the transduction mechanisms for glucose-induced insulin release in the GK rat.
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PMID:Dysfunction of the islet lysosomal system conveys impairment of glucose-induced insulin release in the diabetic GK rat. 1038 96

alpha-1,4-Linked oligogalacturonides (OGs) inhibit auxin-regulated transcriptional activation of a rolB-beta-glucuronidase (GUS) gene fusion in tobacco (Nicotiana tabacum) leaf explants (D. Bellincampi, M. Cardarelli, D. Zaghi, G. Serino, G. Salvi, C. Gatz, F. Cervone, M. M. Altamura, P. Costantino, G. De Lorenzo [1996] Plant Cell 8: 477-487). In this paper we show that inhibition by OGs is very rapid, with a short lag time, and takes place even after rolB promoter activation has initiated. OGs also induce a transient and catalase-sensitive accumulation of H(2)O(2) in the leaf explant culture medium. OGs with a degree of polymerization from 12 to 15 are required for both the inhibition of the auxin-induced rolB-driven accumulation of GUS and the induction of H(2)O(2) accumulation(.) However, OG concentration for half-maximal induction of H(2)O(2) accumulation is approximately 3-fold higher than that for half-maximal inhibition of rolB promoter activity. The inhibition of rolB promoter activity is not influenced by the addition of catalase or superoxide dismutase, suggesting that H(2)O(2) and superoxide are not involved in this effect. A fungal oligo-beta-glucan elicitor induces extracellular H(2)O(2) accumulation at comparable or higher levels than those observed with OGs, but does not prevent the auxin-induced accumulation of GUS. We conclude that H(2)O(2) produced upon treatment with OGs is not involved in the inhibition of the auxin-induced expression of the rolB gene.
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PMID:Extracellular H(2)O(2) induced by oligogalacturonides is not involved in the inhibition of the auxin-regulated rolB gene expression in tobacco leaf explants. 1075 34

Laminarin, a beta-1,3 glucan with single beta-glucose branches at position 6, was chemically sulfated to produce PS3 with a degree of sulfation of 2.4. PS3 has previously been shown to activate the salicylic acid (SA) signaling pathway in infiltrated tobacco and Arabidopsis thaliana leaf tissues. Here, we investigated whether PS3 induces systemic defense and resistance responses in tobacco. Using a radiolabeled compound, it was first demonstrated that PS3 remains strictly localized to the infiltrated tissues. PS3 is also resistant to beta-glucanase degradation. In transgenic PR1-beta-glucuronidase (GUS) tobacco plants, PS3 causes a strong increase in GUS activity in treated tissues but none in untreated leaves. PS3-infiltrated tissues challenged with tobacco mosaic virus (TMV) 8 d after elicitor application show a decrease in both the lesion number and the lesion size, whereas treatment with laminarin, the unsulfated native glucan, affected only the lesion number. PS3 does not induce systemic acquired resistance to TMV. PS3 and laminarin show synergistic effects in promoting the oxidative burst in tobacco cell suspensions and in increasing the expression of genes encoding O-methyltransferases of the phenylpropanoid pathway in tobacco plants. No synergistic effect was observed on the expression of either the SA-dependent acidic PR1 gene or the ethylene-dependent basic PR5 gene in tobacco plants.
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PMID:Defense and resistance-inducing activities in tobacco of the sulfated beta-1,3 glucan PS3 and its synergistic activities with the unsulfated molecule. 1621 71

We have identified a number of ecto-glycanases (glycosylhydrolases) associated with the capsule and/or the cell wall of Cryptococcus neoformans. The enzyme activities detected included alpha-mannosidase, alpha-, and beta -glucosidase, alpha-, and beta-galactosidase, beta-xylosidase, beta-glucuronidase, and endo-beta-1,3-glucanase. Small portions of the enzymes were also secreted into the growth medium. Cell-wall associated endo-beta-1,3-glucanases exhibited highest activity in the acidic range between pH 2.5 and 5.0. The products of laminarin hydrolysis by the enzymes located on the cell surface were glucose and beta-1,3-linked glucooligosaccharides. The same products were released from isolated cell walls incubated in the buffer. Endo-beta-1,3-glucanase activity extracted from the cell surfaces by mild sonication consisted of six isoforms separable by isoelectric focusing. In spite of the presence of the whole array of glycanase activities on the cell surfaces, capsular polysaccharides released from C. neoformans cells into the growth medium were practically metabolically stable. From the defined polysaccharides tested, only laminarin (beta-1,3-glucan) and to some extent also mixed-linkage beta-1,3/beta-1,4-glucan and/or 4-O-methyl-D-glucurono-D-xylan were able to support the yeast growth. The activities of majority of identified ecto-glycanases were low when the yeast was grown on glucose but were considerably elevated when the cells were grown on glycerol indicating that their synthesis is regulated by catabolite repression.
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PMID:Ecto-glycanases and metabolic stability of the capsule in Cryptococcus neoformans. 1713 12


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