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)

Bovine factor VIII aggregates human platelets either in a strong single wave at high concentration (10 mug/ml platelet suspension) or in two waves at low concentration (0.2-I mug/ml). The strong single wave of aggregation is not associated with release of [14C]serotonin or beta-glucuronidase; the high concentration does not induce retraction of reptilase-clotted platelet-rich plasma. Wtih the low concentration, relase of [14C]serotonin is observed just prior to the onset of the second wave of aggregation; release of beta-glucuronidase does not occur at any moment. The low concentration of bovine factor VIII induces moderate retraction of reptilase-clotted platelet-clotted platelet-rich plasma, which is inhibited by acetylsalicylic acid, indomethacin and apyrase, indicating that it is a consequence of release of platelet adenosine-5'-diphosphate. It has previously been suggested tht carbohydrate groups are involved in the human platelet-bovine factor VIII interaction, since galactose oxidase and periodate oxidation abolish the platelet aggregating activity of bovine factor VIII. The present study shows that these oxidizing substances also induce a degradation of bovine factor VIII, so that the exact role of carbohydrate groups in the aggregation process remains to be established.
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PMID:Factor VIII and human platelet aggregation. II. Characteristics of aggregation of human platelets by bovine factor VIII. 98 97

Thrombocytopenia is a common accompaniment of disseminated histoplasmosis. The yeast form of Histoplasma capsulatum does not directly injure human platelets freed of plasma. Preincubation of H. capsulatum with plasma enabled it to induce prompt platelet aggregation and selective release of [3H]serotonin without release of lysosomal beta-glucuronidase and the cytoplasmic marker, lactate dehydrogenase. Platelet aggregation was mediated by adenosine diphosphate, as shown by the blocking of the reaction by apyrase. Indomethacin inhibited both aggregation and serotonin release, indicating their dependence on prostaglandin synthesis by platelets. Plasma IgG conferred [3H]serotonin-releasing activity after complexing with yeasts, and plasma fibrinogen was necessary for platelet aggregation; classical and alternative complement pathways were not involved. The interaction of H. capsulatum with human platelets, mediated by IgG and fibrinogen without complement, represents a new attribute of this fungal pathogen and may contribute to thrombocytopenia complicating disseminated histoplasmosis.
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PMID:Interaction of Histoplasma capsulatum with human platelets. 740 Jun 26

In Arabidopsis, we previously identified two highly similar apyrases, AtAPY1 and AtAPY2. Here, T-DNA knockout (KO) mutations of each gene were isolated in a reverse genetic approach. The single KO mutants lacked a discernible phenotype. The double KO mutants, however, exhibited a complete inhibition of pollen germination, and this correlated with positive beta-glucuronidase staining in the pollen of apyrase promoter:beta-glucuronidase fusion transgenic lines. The vast majority of the pollen grains of these mutants were identical to wild type in size, shape, and nuclear state and were viable as assayed by metabolic activity and plasma membrane integrity. Complementation with either AtAPY1 or AtAPY2 cDNA rescued pollen germination, confirming that the phenotype was apyrase specific. Despite the redundancy of the two apyrases in rescue potential, transmission analyses suggested a greater role for AtAPY2 in male gamete success. The effect of mutant apyrase on the transmission through the female gametophyte was only marginal, and embryo development appeared normal in the absence of apyrases. The male-specific double KO mutation is fully penetrant and shows that apyrases play a crucial role in pollen germination.
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PMID:Disruption of apyrases inhibits pollen germination in Arabidopsis. 1269 23

Expression of two Arabidopsis (Arabidopsis thaliana) apyrase (nucleoside triphosphate-diphosphohydrolase) genes with high similarity, APY1 and APY2, was analyzed during seedling development and under different light treatments using beta-glucuronidase fusion constructs with the promoters of both genes. As evaluated by beta-glucuronidase staining and independently confirmed by other methods, the highest expression of both apyrases was in rapidly growing tissues and/or tissues that accumulate high auxin levels. Red-light treatment of etiolated seedlings suppressed the protein and message level of both apyrases at least as rapidly as it inhibited hypocotyl growth. Adult apy1 and apy2 single mutants had near-normal growth, but apy1apy2 double-knockout plants were dwarf, due primarily to reduced cell elongation. Pollen tubes and etiolated hypocotyls overexpressing an apyrase had faster growth rates than wild-type plants. Growing pollen tubes released ATP into the growth medium and suppression of apyrase activity by antiapyrase antibodies or by inhibitors simultaneously increased medium ATP levels and inhibited pollen tube growth. These results imply that APY1 and APY2, like their homologs in animals, act to reduce the concentration of extracellular nucleotides, and that this function is important for the regulation of growth in Arabidopsis.
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PMID:Apyrases (nucleoside triphosphate-diphosphohydrolases) play a key role in growth control in Arabidopsis. 1743 87