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)

Basophilic granulocytes were purified from the blood of normal individuals by successive isopyknic centrifugation and elutriation centrifugation. Starting with the leukocyte-rich fraction of 500 ml of blood, we recovered 31 to 80% (mean 51%, n = 20) of the basophils in 45 to 87% purity (mean 69%, n = 23). The contaminating cells were mainly lymphocytes. The basophils were greater than 98% vital (exclusion of ethidium bromide and hydrolysis of fluorescein diacetate). The histamine content of the basophils was 1.1 to 2 pg/cell (mean 1.6 pg/cell, n = 22). With anti-IgE, 30 to 50% of the histamine was released; with phorbol myristic acetate (PMA) or the calcium ionophore A23187, 70 to 100% of the histamine was released. Serum-opsonized zymosan (STZ) did not induce histamine release. Reactions with monoclonal antibodies revealed that the basophils expressed the C3bi receptor (CR3) and the leukocyte function-associated antigen 1 (LFA1), but not the gp 150,95 antigen, the C3b receptor (CR1), or the low avidity Fc gamma receptor. Basophils carry class I but not class II HLA antigens. During incubation of the basophils with serum-opsonized Staphylococcus aureus or Escherichia coli, these bacteria were neither phagocytized nor killed. STZ, PMA, A23187, or anti-IgE did not initiate an "oxidative burst" in the basophils. This was tested with oxygen consumption, cytochrome c reduction, NBT reduction, chemiluminescence, and release of hydrogen peroxide. Moreover, we did not detect cytochrome b558, superoxide dismutase, catalase, or peroxidase in the basophils. Of the typical granule-associated enzymes lysozyme, Vitamin B12-binding protein, and beta-glucuronidase, only beta-glucuronidase was present in the basophils in detectable amounts. This enzyme was released, together with histamine, on incubation of the cells with PMA, A23187, or anti-IgE, but not with STZ. We conclude that basophils from normal human blood are not phagocytes and are probably not involved in the oxidative defense of the host against foreign antigens.
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PMID:Metabolic comparison between basophils and other leukocytes from human blood. 300 19

We have investigated the interaction between quartz and granulocytes with respect to complement receptor expression. When N-formylmethionyl-leucyl-phenylalanine (fMLP)-stimulated leukocytes were exposed to quartz at 37 degrees C, CR1 was down-regulated but CR3 was not affected. This was a direct effect on granulocytes because it occurred in a similar fashion when mixed leukocyte suspensions and isolated granulocyte populations were used as targets for quartz. The observed down-regulation by quartz was not affected by the microfilament-disrupting agent cytochalasin B and the total detectable pool of CR1 was reduced after quartz exposure. When protease inhibitors, such as aprotinin or phenylmethanesulfonyl fluoride, were present during quartz exposure, the down-regulation of CR1 was less pronounced, but this was not the case not when protease inhibitors such as EDTA-Na2 and pepstatin were present. Exposure to quartz was not accompanied by a pronounced release of beta-glucuronidase (marker for the primary granules) or vitamin B12 binding protein (marker for the secondary granules). In contrast to quartz, exposure to alumina did not affect the expression of CR1 and CR3. The spontaneous mobilization of CR1 at 37 degrees C was reduced when quartz was present but the CR3 mobilization was unaffected. Our results indicate that quartz induces a granule protease-dependent selective shedding of CR1 but not CR3 despite a low degree of degranulation.
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PMID:Quartz selectively down-regulates CR1 on activated human granulocytes. 767 48

Two winter barley (Hordeum vulgare L. cv. Igri) genomic clones, lambda gblt101.1 and lambda gblt101.2, encoding the blt101 gene family, were isolated from a genomic library. Deletion analysis of the blt101.1 promoter, using transient beta-glucuronidase (GUS) reporter expression assays, indicated that it contains at least three regulatory regions. A 107-bp region between nucleotides -168 and -275 with respect to the translation initiation codon, confers high-level GUS reporter expression at low temperature and contains a sequence (designated CR1) that is highly conserved in equivalent positions within the promoters of both members of the blt101 gene family. A 10-bp motif contained within CR1 binds proteins present in nuclear extracts from both control and low-temperature-treated barley tissue. Loss-of-function experiments, using transient-expression analysis, confirmed that this motif acts as a previously unreported low-temperature-responsive element. Nuclease sensitivity analysis of intact chromatin indicated that the blt101.1 promoter becomes more susceptible to DNase and micrococcal nuclease at low temperature, consistent with chromatin reorganisation upon transcriptional induction. It is proposed that both the 10-bp motif and chromatin reorganisation are involved in the regulation of blt101.1 at low temperature. This is the first detailed analysis of a low-temperature-specific plant promoter and identifies a novel low-temperature-response element.
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PMID:Identification of a novel low-temperature-response element in the promoter of the barley (Hordeum vulgare L) gene blt101.1. 1167 82