The detailed chemical composition and microstructure of freshly deposited bone mineral, and how these properties change with maturation of the mineral, have been studied intensively and still remain controversial. For example, current analytical technology is inadequate for the unambiguous characterization of the monohydrogen phosphate ions in bone mineral. Using a ...

Venoms from two related Australian ants, a jumper ant (Myrmecia pilosula) and a bulldog ant (Myrmecia pyriformis), were quantitatively analysed for the following enzymic activities: phospholipase A2, phospholipase B, phospholipase C, hyaluronidase, esterase, acid phosphatase, alkaline phosphatase and phosphodiesterase. Both venoms contained phospholipase A2, phospholipase B, hyaluronidase, acid phosphatase and ...

Hemolymph phenoloxidase activity of sugar-fed and blood-fed females of Anopheles quadrimaculatus and Aedes aegypti showed similar characteristics. Phenoloxidase was present as an inactive proenzyme in both mosquito species and was partially activated during collection of the hemolymph. In both mosquito species, phenoloxidase activity was modulated by different buffers and activated ...

Three secreted acid phosphatases had previously been characterized from Aspergillus ficuum grown under conditions of limited phosphate. One of these could not be readily separated from AFPhyB, a pH 2.5 optimum acid phosphatase with phytase activity. From extensive protein sequence analysis and subsequent cloning of the gene, we have shown ...

The effects of parenteral glucose, cyclic AMP and caffeine on the breakdown of glycogen in the lysosomes of newborn rat hepatocytes, were studied by using biochemical assays, electron microscopy and quantitative morphometry. Glucose prevented the normal postnatal increase in lysosomal volume, acid alpha 1,4 glucosidase activity and lysosomal glycogen breakdown. ...

In this work, an attempt was made to asses possible regional specializations in the llama ductus epididymidis. According to histological and histochemical criteria, six segments (I-VI) were identified. Segment I was a short region where ductuli efferentes joined the ductus epididymidis. Segments II and III showed maximal epithelial height and ...

A Citrobacter sp. was reported previously to accumulate heavy metals as cell-bound heavy metal phosphates. Metal uptake is mediated by the activity of a periplasmic acid-type phosphatase that liberates inorganic phosphate to provide the precipitant ligand for heavy metals presented to the cells. Amino acid sequencing of peptide fragments of ...

The specificity of five mouse monoclonal antibodies to okadaic acid was studied for use in an enzyme-linked immunosorbent assay of okadaic acid and its analogs. OA8-2 and OA22-22 antibodies (IgG2a-kappa), which bind more strongly to dinophysistoxin-1 and 7-O-palmitoyl-dinophysistoxin-1 than to okaic acid or 7-O-palmitoyl-okadaic acid in 50% aqueous methanol, were ...

Red cell acid phosphatase (ACP1), adenylate kinase 1 (AK1), and aminolevulinate dehydratase (ALAD) polymorphisms were studied in a population sample from Northern Portugal. The gene frequency estimates found were: ACP1*A = 0.2825, ACP1*B = 0.6625, ACP1*C = 0.0547, ACP1*R = 0.0003 (N = 1517); AK1*1 = 0.9778, AK1*2 = 0.0213, ...

The cytochemical characterization of head-kidney and peripheral blood leucocytes of gilthead seabream (Sparus aurata L.) was studied by light and electron microscopy. Neutrophilic granulocytes show some cytoplasmic granules, which are positive for alkaline phosphatase and peroxidase but acid phosphatase negative. The scarce granules found in the cytoplasm of the circulating ...

In this work we report that superoxide dismutase is entrapped in a microbody-like organelle, the glycosome, present in Leishmania spp. Studies on the sensitivity of the enzyme to various inhibitors indicated that glycosomal superoxide dismutase is predominantly of the Cu/Zu type. Localization of superoxide dismutase in glycosomes points to the ...

Phosphatidylglycerolphosphate (PGP) synthase and PGP phosphatase catalyze the sequential synthesis of phosphatidylglycerol from cytidine-5'-diphosphate 1,2-diacyl-sn-glycerol (CDP-DG) and glycerol-3-phosphate. PGP synthase and PGP phosphatase activities were characterized in rat heart mitochondrial fractions, and the effect of fatty acids on the activity of these enzymes was determined. PGP synthase was observed to ...

The effects of meso-2,3-dimercaptosuccinic acid (DMSA) and 2,3-dimercaptopropane sulphonate (DMPS) on body beryllium burden, hepatic lipid peroxidation, glutathione, alkaline and acid phosphatase and some biochemical variables of porphyrin metabolism were studied in beryllium-poisoned rats. It was observed that beryllium poisoning is associated with a slight increase in lipid peroxidation, significant ...

Erythrogenic toxin type C (ETC) from different streptococcal group A strains was successively purified by absorption on phenylsepharose, acidic dialysis of the eluate at 40% saturated ammonium sulphate solution, CM-Sepharose chromatography, finally by immunoaffinity chromatography on monoclonal antibodies. Second, after growing of bacteria in the presence of [32P]orthophosphate to phosphorylate ...

Phosphatase activities were investigated in Morganella morganii, which is one of the few enterobacterial species producing high-level phosphate-irrepressible acid phosphatase activity (HPAP phenotype), and the gene encoding the major phosphate-irrepressible acid phosphatase was cloned, sequenced, and its product characterized. Using p-nitrophenyl phosphate as substrate, Morganella produced a major phosphate-irrepressible acid ...

Ceramide is ubiquitously present in plasma membranes and plays a pivotal role in metabolism of sphingolipids. In addition, ceramide and its hydrolytic product, sphingosine, may have important roles as second messengers for cell function and survival. Ceramide is hydrolyzed by both acid and alkaline ceramidase. In this investigation, saposin D ...

Lysosome-disrupting enzyme substrates have been used to distinguish between lysosomal and prelysosomal compartments along the endocytic pathway in isolated rat hepatocytes. The cells were incubated for various periods of time with 125I-labelled tyramine cellobiose (125I-TC) covalently coupled to asialoorosomucoid (AOM) (125I-TC-AOM); this molecule is internalized by receptor-mediated endocytosis and degraded ...

Tetrahydrobiopterin (BH4), the obligatory cofactor of the aromatic amino acid hydroxylases, decreased the in situ 32P-phosphorylation of tyrosine hydroxylase (TH) in rat striatal synaptosomes. Incubation of pre-32P-labeled synaptosomes with BH4 in the presence of a permeant analogue of cAMP decreased the cAMP-stimulated level of 32P label incorporation into TH by ...

Effects of single doses of kumari asav, kumari kalp, arogyavardhini and tamra bhasma on lysosomal enzymes (acid phosphatase and beta-glucuronidase) of rat liver and kidney were studied during hepatitis induced by single 0.3 ml/kg body wt dose of CCl4. Histologically all the drugs showed significant hepatoprotection. While acid phosphatase activities ...

Three soluble forms of membrane attack complex inhibitory factor (MACIF or CD59) were prepared using recombinant baculovirus-infected insect cells. They consisted of 70, 77 and 86 amino acids, starting from the amino terminus of naturally occurring CD59, and were designated recombinant (r) CD59 70, 77 and 86, respectively. All three ...

In previous studies, we demonstrated that while okadaic acid stimulates glucose metabolism, it suppresses the bioresponses of insulin itself in rat adipocytes (Shisheva and Shechter, Endocrinology 129: 2279-2288, 1991). Both stimulation and suppression were attributed to okadaic acid-dependent inhibition of protein phosphatases 1 and 2A. We report here that exposure ...

Dystrophic axons (DAs) in rat gracile nuclei were largely classified into two types. One type had a focal swelling measuring about 2-8 microns in diameter, and contained greatly increased numbers of various cellular organelles. Numerous reaction products of acid phosphatase (ACPase) cytochemistry were deposited in the cytoplasmic matrix and the ...

In the regenerating limbs of Korean salamanders, Hynobius leechii, retinoic acid (RA) induces duplication of skeletal structures in the proximodistal (PD) axis and often in the transverse axes. In the present study, the stage-dependent effects of RA for the duplication of limb skeletal structures at two amputation levels, the distal ...

Type 5 acid phosphatase is a lysosomal enzyme expressed in cells of monocyte/macrophage lineage frequently used as a marker of osteoclastic differentiation. Oligonucleotide primers for DNA amplification were designed following sequence alignment of rat bone and human macrophage type 5 acid phosphatases. DNA (330 bp in length) obtained using these ...

The effects of ammonia loading in the terrestrial isopod Porcellio scaber were studied by exposing animals to atmospheres of high PNH3. Isopods show a remarkable tolerance of elevated ambient PNH3, with an LD50 of 89 Pa for a 7-day exposure. However, haemolymph total ammonia concentrations generally remained below 5 mmol ...

Protein-tyrosine phosphatases (PTPases) contain an evolutionarily conserved segment of 250 amino acids referred to as the PTPase catalytic domain. The recombinant PTPase domain from Yersinia enterocolitica enhances the rate of hydrolysis of p-nitrophenyl phosphate, a phosphate monoester, by approximately 10(11) over the non-enzyme-catalyzed rate by water. Specific amino acid residues ...

The murine polyether fatty acid, okadaic acid, is a potent inhibitor of serine/threonine phosphatases in eukaryotic cells. This compound inhibits both protein phosphatase 1 (PP1) and phosphatase 2A (PP2A). Here we have examined the potential of okadaic acid as an activator of fresh peripheral CD3- large granular lymphocytes (LGL). We ...

Twenty seven biopsies of articular cartilage taken intraoperatively from patients with Rheumatoid arthritis (RA) and from control patients with traumas were examined using histopathological techniques (HE, VG, PAS-Alcian, Gömöri, Safranine 0) and histoenzymological techniques (Acid phosphatase-lysomal marker, Chondroitinsulphatase, Peroxidase). Histopathologically, the rheumatoid articular cartilage appears with superficial and deep cartilaginous ...

The oxidative metabolites have been implicated in the aetiology and pathology of rheumatoid arthritis. In our work we endeavoured to deal with polymorphonuclear leukocytes (PMNLs) ability to generate oxygen free radicals (OFRs). PMNLs metabolic activity was assessed by the means of chemiluminescence (CL) method. We observed significantly higher PMNLs metabolic ...

The effect of the protein phosphatase inhibitor okadaic acid on phospholipase C (PLC)-linked signal transduction processes was investigated in intact hepatocytes. A short (5 min) pretreatment of the hepatocytes with okadaic acid (1 mu M) markedly inhibited a subsequent stimulation of PLC by ethanol as well as by receptor-mediated stimuli ...

A method was developed for fractionation and isolation of toxic components present in extracts prepared from Dinophysis-contaminated mussels. The major toxin present in French mussels was identified as okadaic acid by its chromatographic properties and spectral data. Large amounts of mussel tissue (digestive glands and remaining meat) can be treated ...

It is shown here that treatment of metaphase-arrested HeLa cells with okadaic acid (0.15-2.5 microM) leads to dephosphorylation of histone H1. This effect is presumably due to the specific ability of okadaic acid to inhibit protein phosphatases 1 and/or 2A, because okadaic acid tetraacetate, which is not a phosphatase inhibitor, ...

Inclusion of salmon calcitonin in the culture medium of rat ventral prostate explants diminished l-tartarate-sensitive acid phosphatase activity in the tissues with a concomitant increment of the enzyme activity in the medium. The effect of the hormone was dose-dependent for a dose range of 10(-12)-10(-6) M. Acid phosphatase activity in ...

We report the syntheses of two new fluorescein derivatives, 3',6'-dihydroxy-3-oxo-2-[(phosphonothio)-acetyl]spiro[isobenzof uran- 1(3H),9'-9H-xanthene]-6-carboxylic acid hydrazide, disodium salt, a phosphorothioate fluorescein, and 3',6'-dihydroxy-3-oxo-2-(mercaptoacetyl)spiro[isobenzofuran-1(3H), 9'-9H- xanthene]-6-carboxylic acid hydrazide, a mercaptoacetyl fluorescein. The latter is derived from the first compound by hydrolysis of the phosphate. Direct nonenzymatic labeling of the maleimide-derivatized IgG molecule by ...

Glucocorticoids induce apoptosis in murine T cell hybridomas. It was inhibited by okadaic acid and calyculin A, potent inhibitors of protein phosphatase 1 and 2A, but not by 1-norokadaone, a structural analog of okadaic acid without phosphatase inhibitory activity. The inhibitory effect of okadaic acid was significant even when it ...

Hepatotoxic microcystins produced by cyanobacteria in freshwater lakes represent a significant health hazard to humans and agricultural livestock. Liquid chromatography (LC)-linked protein phosphatase (PPase) bioassay analysis of blooms of Microcystis aeruginosa produced in a Canadian drinking water lake identified several PPase inhibitors with significantly greater hydrophobicity than microcystin-LR, based on ...

We have detected phosphohistidine and phospholysine phosphatase activities in rat tissue extracts using partially phosphorylated, high-molecular-mass (> 10 kDa) polymers of histidine and lysine as substrates. Multiple phosphohistidine- and phospholysine-specific phosphatases were present in these extracts based on observed differences in heat stability, sensitivity to bivalent metal ions and thiol ...

The effects of the phosphatase inhibitors calyculin A and okadaic acid were investigated to determine the roles of protein phosphatases type 1 and 2A in the regulation of the activities of glycogen synthase and phosphorylase by glucose in a primary culture of hepatocytes. Glycogen synthesis, as measured by the incorporation ...

The content of the large vacuoles present in chicken thrombocytes was analyzed by the use of cytochemical techniques which indicated the presence of basic proteins, unsaturated fatty acids, sugars rich in viccinal hydroxyl groups, linked to proteins or lipids and acid phosphatase. These substances perform one of the most conspicuous ...

The tumor promoter okadaic acid is a potent inhibitor of the serine/threonine protein phosphatases 1 and 2A. Addition of okadaic acid to v-Src-transformed BALB/c 3T3 cells reverted them to a flat morphology, increased fibronectin levels in the extracellular matrix, reduced saturation density, and inhibited the formation of colonies in soft ...

The protein phosphatase inhibitor okadaic acid was used to investigate the role of protein phosphatases in regulating the release of amino acids from synaptosomes. Okadaic acid increased the basal release of the amino acids glutamate, aspartate and GABA. The effect was specific in that taurine was not released by either ...

Okadaic acid, a cell-permeant inhibitor of serine/threonine phosphatases (PP) was found to attenuate the IgE-mediated release of both performed (histamine) and newly formed (leukotriene C4) mediators from human lung mast cells (HLMC). Optimal inhibition (82 +/- 6%) of the IgE-triggered release of histamine was observed after a 2-h incubation of ...

High concentrations of okadaic acid, sufficient to inhibit phosphatase 1 and 2A activities, induces formation of diplochromosomes in HeLa cells. It has been shown that this is due to a failure of sister chromatid separation in earlier mitosis in the presence of okadaic acid in the medium and not due ...

A method is described for large-scale purification of glycosylphosphatidylinositol-anchored alkaline phosphatase from intestinal mucosa and chyme to homogeneity. Both enzyme preparations contain approximately 2 mol fatty acid/mol subunit and exhibit a very similar fatty acid composition with octadecanoate and hexadecanoate as prevalent components. No significant differences between native glycosylPtdIns-anchored and ...

Liver lysosomes were isolated from untreated rats and rats pretreated with Triton WR-1339. Purified lysosomes were also separated into lysosomal matrix and membrane fractions. With freshly prepared and frozen biological material, the lysosomal catabolism of various stereospecifically radiolabeled amino alcohol-containing glycerophospholipids and their potential metabolites was studied. Basically there was ...

A comparative study of the spectral, electrophoretic and isoelectric properties of the haemoglobins of three trematodes, Paramphistomum epiclitum, Gigantocotyle explanatum and Gastrothylax crumenifer was carried out. A high absorption in the beta band region indicates that trematode haemoglobins have high oxygen affinities. Electrophoretic mobilities of all trematode and their host ...

Okadaic acid (OA), the main toxin responsible for diarrheic shellfish poisoning (DSP) has toxicity for Daphnia magna (EC50 = 15 +/- 1.8 micrograms/l). A Daphnia bioassay was developed and used to analyse okadaic acid in mussel extracts. A linear correlation was found between OA concentration determined by the Daphnia bioassay ...

Okadaic acid, a newly recognized protein phosphatase inhibitor and a non-TPA type tumor promoter, enhanced 1 alpha 25(OH)2D3(D3)-induced HL-60 cell differentiation into monocyte/macrophage lineage but did not affect dibutyryl cyclic AMP (dbcAMP)-induced differentiation into granulocytic lineage. Okadaic acid alone did not induce any differentiation. The process of D3-induced HL-60 cell ...

Okadaic acid exerts a positive inotropic effect in cardiac preparations. We studied whether the positive inotropic effect of okadaic acid in cardiac preparations could be due to phosphatase inhibition and whether this inhibition affects the phosphorylation of cardiac proteins. In papillary muscles from guinea pigs, 30 microM okadaic acid increased ...

To understand the bone resorption and lysosomal proteinases in osteoclasts, we examined by immunohistochemistry the localization of lysosomal cysteine and aspartic proteinases, acid phosphatase, and cystatin-beta in the rat tibial bone. Immunoreactivity for cathepsins B, C, H, and L, cathepsin D, acid phosphatase, and cystatin-beta was demonstrated in various cells ...