Measurement of the arylsulphatase of Patella vulgata with 4-methylumbelliferone sulphate

Silkworm arylsulfatase in the midgut content is expressed in the silk gland and fed via smearing on the food from the spinneret

We found the activity of arylsulfatase in the midgut contents of the silkworm, Bombyx mori. We identified a 60-kDa protein that comigrates with the activity on a column chromatography following ammonium sulfate precipitation. Based on its partial amino acid sequence, we searched for its coding gene using Basic Local Alignment Search Tool (BLAST) and identified KWMTBOMO05106. Transcriptional data suggest a specific expression of the gene in middle silk glands. The majority (80%) of arylsulfatase activity was found in the silk glands, concurring the specific transcription in the silk gland. Observing the feeding behaviour of the silkworm, we found that silkworms smear a mucus secretes from the spinneret on the food pellet as they feed on. Arylsulfatase activity was also detected in the food pellet bitten by the silkworm as well as in the gut content. Furthermore, arylsulfatase activity was not detected either in the food pellet and in the gut content when silkworms had obstructed the spinneret. These results suggest that arylsulfatase is secreted from the silk glands and may contribute to digestive function.

An Insect Counteradaptation against Host Plant Defenses Evolved through Concerted Neofunctionalization

Antagonistic chemical interactions between herbivorous insects and their host plants are often thought to coevolve in a stepwise process, with an evolutionary innovation on one side being countered by a corresponding advance on the other. Glucosinolate sulfatase (GSS) enzyme activity is essential for the Diamondback moth, Plutella xylostella, to overcome a highly diversified secondary metabolite-based host defense system in the Brassicales. GSS genes are located in an ancient cluster of arylsulfataselike genes, but the exact roles of gene copies and their evolutionary trajectories are unknown. Here, we combine a functional investigation of duplicated insect arylsulfatases with an analysis of associated nucleotide substitution patterns. We show that the Diamondback moth genome encodes three GSSs with distinct substrate spectra and distinct expression patterns in response to glucosinolates. Contrary to our expectations, early functional diversification of gene copies was not indicative of a coevolutionary arms race between host and herbivore. Instead, both copies of a duplicated arylsulfatase gene evolved concertedly in the context of an insect host shift to acquire novel detoxifying functions under positive selection, a pattern of duplicate gene retention that we call “concerted neofunctionalization.”

Synthesis and evaluation of turn-on fluorescent probes for imaging steroid sulfatase activities in cells

A self-immobilizing probe with the coumarin moiety is designed to detect the human steroid sulfatase intracellularly by fluorescence turn-on imaging.

Sulfatase-activated fluorophores for rapid discrimination of mycobacterial species and strains

Most current diagnostic tests for tuberculosis do not reveal the species or strain of pathogen causing pulmonary infection, which can lead to inappropriate treatment regimens and the spread of disease. Here, we report an assay for mycobacterial strain assignment based on genetically conserved mycobacterial sulfatases. We developed a sulfatase-activated probe, 7-hydroxy-9H-(1,3-dichloro-9,9-dimethylacridin-2-one)-sulfate, that detects enzyme activity in native protein gels, allowing the rapid detection of sulfatases in mycobacterial lysates. This assay revealed that mycobacterial strains have distinct sulfatase fingerprints that can be used to judge both the species and lineage. Our results demonstrate the potential of enzyme-activated probes for rapid pathogen discrimination for infectious diseases.

Expert recommendations for the laboratory diagnosis of MPS VI

Mucopolysaccharidosis VI (MPS VI) is a lysosomal storage disease caused by a deficiency of N-acetylgalactosamine 4-sulfatase (arylsulfatase B, ASB). This enzyme is required for the degradation of dermatan sulfate. In its absence, dermatan sulfate accumulates in cells and is excreted in large quantities in urine. Specific therapeutic intervention is available; however, accurate and timely diagnosis is crucial for maximal benefit. To better understand the current practices for diagnosis and to establish diagnostic guidelines, an international MPS VI laboratory diagnostics scientific summit was held in February of 2011 in Miami, Florida. The various steps in the diagnosis of MPS VI were discussed including urinary glycosaminoglycan (uGAG) analysis, enzyme activity analysis, and molecular analysis. The following conclusions were reached. Dilute urine samples pose a significant problem for uGAG analysis and MPS VI patients can be missed by quantitative uGAG testing alone as dermatan sulfate may not always be excreted in large quantities. Enzyme activity analysis is universally acknowledged as a key component of diagnosis; however, several caveats must be considered and the appropriate use of reference enzymes is essential. Molecular analysis supports enzyme activity test results and is essential for carrier testing, subsequent genetic counseling, and prenatal testing. Overall the expert panel recommends caution in the use of uGAG screening alone to rule out or confirm the diagnosis of MPS VI and acknowledges enzyme activity analysis as a critical component of diagnosis. Measurement of another sulfatase enzyme to exclude multiple sulfatase deficiency was recommended prior to the initiation of therapy. When feasible, the use of molecular testing as part of the diagnosis is encouraged. A diagnostic algorithm for MPS VI is provided.

DNA Binding Hydroxyl Radical Probes

The hydroxyl radical is the primary mediator of DNA damage by the indirect effect of ionizing radiation. It is a powerful oxidizing agent produced by the radiolysis of water and is responsible for a significant fraction of the DNA damage associated with ionizing radiation. There is therefore an interest in the development of sensitive assays for its detection. The hydroxylation of aromatic groups to produce fluorescent products has been used for this purpose. We have examined four different chromophores which produce fluorescent products when hydroxylated. Of these, the coumarin system suffers from the fewest disadvantages. We have therefore examined its behavior when linked to a cationic peptide ligand designed to bind strongly to DNA.

Leishmania mexicana: amastigote hydrolases in unusual lysosomes

Leishmania mexicana mexicana (M379) amastigotes were found to contain much higher activities than cultured promastigotes of five putative lysosomal enzymes: cysteine proteinase; arylsulfatase (EC 3.1.6.1); beta-glucuronidase (EC 3.2.1.31); DNase (EC 3.1.22.1), and RNase (EC 3.1.27.1). The release profiles of the first three of these enzymes from digitonin-permeabilized amastigotes suggests that they are located within organelles. Cytochemical staining for cysteine proteinase, using gold labeled antibodies and arylsulfatase, showed that both were present in large organelles previously named "megasomes." Comparative studies with L. mexicana amazonensis (LV78), L. donovani donovani (LV9), and L. major (LV39) revealed that L. mexicana amazonensis was similar to L. mexicana mexicana in possessing both high amastigote cysteine proteinase activity and large numbers of megasome organelles in amastigotes, whereas the other two species lacked both these features. The results suggest that the presence of numerous lysosome-like organelles in the amastigote is a characteristic of the L. mexicana group of parasites.

Isolation of a purified mitochondrial fraction from viable clonal insulin-producing cells (RINm5F) by Percoll density gradient centrifugation

A Percoll density gradient was employed for selecting large numbers of viable insulin-producing RINm5F cells. Homogenates of these cells were then subjected to gradient centrifugation and two clearly visible bands were obtained. The light fraction was essentially composed of mitochondria banded at a density of about 1.06 g/ml. The heavier fraction banded at 1.09 to 1.10 g/ml and contained lysosomes and a small number of secretory granules. The distribution of Percoll particles was restricted to the extracellular space and there was no adsorption to any membrane structures. The distribution pattern of marker enzymes for the mitochondria and lysosomes was similar to that of normal pancreatic beta-cells. With the use of a Percoll density gradient it was thus possible to isolate a purified mitochondrial fraction from viable RINm5F cells.

Glucose-induced retention of intracellular 45Ca in pancreatic islets

beta-Cell-rich pancreatic islets from ob/ob mice were loaded with 45Ca in the presence of 20 mM glucose. When the islets were transferred to a nonradioactive incubation medium depleted of Ca2+, most of the 45Ca was lost during the first 10 min of incubation irrespective of whether or not glucose was present. Isolation of subcellular fractions under conditions minimizing 45Ca redistribution disclosed that the presence of 20 mM glucose during the nonradioactive incubation increased the retention of 45Ca in the mitochondrial fraction. This effect was not reproduced by K+ depolarization of the islets. Exposure of islets to 4 mM glucose failed to affect the total content of 45Ca in the islets but increased the incorporation of the isotope into cellular organelles. These results suggest that glucose, even at concentrations below the threshold for stimulation of insulin secretion, enhances the intracellular trapping of calcium.

Assay of phenol sulphotransferase in human blood

An assay of phenol sulphotransferase in human blood with 4-hydroxy-3-methoxyphenylethylene glycol as partial substrate is described. The pH optimum with this substrate is 8.0. To demonstrate the heterogeneity of the enzyme in blood an alternative partial substrate, 4-methylumbelliferone, at an optimal pH of 7.4, is used. Enzyme activity is linear with time up to at least 60 minutes of incubation. With 4-hydroxy-3-methoxyphenylethylene glycol as the substrate a linear relation between phenol sulphotransferase activity and enzyme concentration exists. Phenol sulphotransferase activity shows no correlation with age or sex of healthy subjects. Varying ratios of the enzyme activities toward both substrates support the idea of two phenol sulphotransferases in blood. As nevertheless a significant correlation exists between both sulphotransferase activities we conclude that neither substrate is sulphated exclusively by one of the two enzymes. Because preparative procedures for platelets may lead to considerable losses of specific subpopulations with relatively low or high enzyme activity, one of the advantages of using whole blood is that the activity in the whole platelet population is determined.

Purification of mitochondria and secretory granules isolated from pancreatic beta cells using Percoll and Sephacryl S-1000 superfine

Mitochondria and secretory granules were isolated from beta-cell-rich pancreatic islets of ob/ob mice. Crude fractions obtained by differential centrifugation were subjected to centrifugation on isotonic Percoll. The gradient medium was removed from the resulting fractions by gel filtration on Sephacryl S-1000 Superfine. When compared to the crude fractions, the purified mitochondrial fraction exhibited a 4.5-fold increase in citrate synthase activity, a 70% reduction of lysosomal arylsulfatase, and a 40% decrease of contamination with granular insulin. In the purified secretory granule fraction, the insulin content was as high as 60% of the total protein (albumin standard) with arylsulfatase unchanged and no detectable citrate synthase activity.

The heterogeneous distribution of beta-glucuronidase in purified Golgi membranes

An improved procedure for the preparation of purified Golgi membranes by upward flotation is described. The mode of binding of membrane fragments to an affinity adsorbent specific for beta-glucuronidase shows that this enzyme has a heterogeneous distribution in Golgi membranes.

Arylsulphatases A and B in human diploid fibroblasts: differential assay with 4-methylumbelliferylsulphate and AgNO3

A new technique is introduced for the differential assay of arylsulphatases A and B in centrifuged homogenates of cultured human skin fibroblasts, using 4-methylumbelliferyl-sulphate as a substrate and AgNO3 as a selective inhibitor of arylsulphatase A. The method can be applied in the diagnosis of metachromatic leucodystrophy, mucopolysaccharidosis type VI and mucosulphatidosis. Normal arylsulphatase activities were found in fibroblasts derived from patients with mucopolysaccharidoses types II, III-A and IV, known to be caused by deficiencies of various other sulphatases.

Heterogeneity of lysosomes originating from rat liver parenchymal cells. Metabolic relationship of subpopulations separated by density-gradient centrifugation

1. A crude lysosomal fraction obtained by differential centrifugation of a rat liver homogenate was subjected to zonal centrifugation in iso-osmotic self-generating gradients composed of modified colloidal silica (Percoll). Analysis of relevant marker-enzyme activities shows a continuous band of considerably purified lysosomal particles in the density range 1.04--1.11 g/ml. 2. A relationship between age and buoyant density of the parenchymal lysosomal subpopulations is indicated by the distribution of 125I-labelled asialoglycoproteins in the heterogeneous lysosomes during the catabolism of the glycoprotein. The labelled asialoglycoprotein first appeared in lysosomal particles of low density, which with time progressively acquired a higher density. Furthermore, 30 min after administration the 125I-labelled asialocaeruloplasmin recovered in the light lysosomes was less degraded than the material recovered in the heavy lysosomes. 3. A lysosomal enzyme (arylsulphatase) was found to possess considerably higher isoelectric points in the heavy lysosomes than in the light lysosomes, which is consistent with a relationship between age and density of the lysosomes.

Comparative activity of sulphatases in human liver on two synthetic substrates

Ion-exchange chromatography and gel chromatography manifested the presence of three different forms of sulphatase activity in human liver using 4-methylumbelliferyl sulphate as substrate. Studies with the substrate 4-nitrocatechol sulphate and inhibition experiments with AgNO3 were also performed on these three different forms of sulphatases. This makes it possible to identify the three forms as arylsulphatase A, B, and C. The conclusion is drawn that the 4-methylumbelliferyl sulphate substrate is inadequate to measure the lysosomal arylsulphatases A and B, but it could be used to measure the microsomal arylsulphatase C.

A sensitive fluorescence assay for the simultaneous and separate determination of arylsulphatases A and B

A sensitive fluorometric assay utilizing 4-methylumbelliferyl sulphate has been developed for the simultaneous determination of arylsulphatases A and B from leucocytes, based on the differential effect of silver ions on the two enzymes. The procedure allows discrimination between normal cases and those with metachromatic leucodystrophy.

Comparative activity of arylsulphatases A and B on two synthetic substrates

Rat liver and human skin fibroblasts arylsulphatase A and B activities on both 4-methylumbelliferyl sulphate and 4-nitrocatechol sulphate were compared. The intracellular distribution of activity differed markedly when 4-methylumbelliferyl sulphate was used from that observed with 4-nitrocatechol sulphate. No discrimination between control and metachromatic leucodystrophy or mucopolysaccharidosis (type VI) could be achieved when 4-methylumbelliferyl sulphate was used as substrate. These results contrast sharply with those obtained with 4-nitrocatechol sulphate and cast doubt on the validity of 4-methylumbelliferyl sulphate as substrate for the determination of arylsulphatase A and B activities.

Characterisation of the lysosomal heterogeneity in Chinese-hamster fibroblasts

1. Homogenates of Chinese hamster fibroblasts have been fractionated by analytical centrifugation techniques. Lysosomes have been characterised and identified by the distinctive behaviour of specific marker constituents. 2. The acid hydrolases of hamster fibroblasts were located in two distinct organelles, characterised by differences in their equilibrium densities and rates of sedimentation. The lighter population of lysosomes with a modal density of 1.10 g cm-3, contained glycosidases, nucleases and acid phosphatase. The denser population, with a modal density of 1.15 g cm-3, contained proteases and arylsulphatase B. 3. Acid hydrolases in both populations showed similar degrees of latency and structure-linked sedimentability. 4. The heterophagic activity of hamster fibroblasts was investigated by growing the cells in the presence of [14C]sucrose, [14C]inulin and Triton WR 1339. These compounds are taken up by the cells and appear to be located in the denser population of lysosomes. 5. The low density of the lighter population of lysosomes appears to result from a high content of cholesterol esters and triacylglycerols. It is suggested that the lysosomes may be the site of storage of a considerable proportion of these lipids in cultured hamster cells.

Arylsulfatases A and B in metachromatic leukodystrophy and Maroteaux-Lamy syndrome: studies with 4-methylumelliferyl sulfate

Metachromatic leukodystrophy and Maroteaux-Lamy syndrome can be diagnosed by assay of leukocyte or fibroblast arylsulfatase A and B activity with the fluorogenic substrate 4-methylumbelliferyl sulfate. The arylsulfatases are extracted into a 27000 x g supernatant by sonication in 0.9% sodium chloride and then separated with CM-32 on columns or in test tubes. In 0.05 M sodium acetate pH 6.0, arylsulfatase A is not absorbed while arylsulfatase B is retained by the resin. The arylsulfatase B is then eluted from the resin with 0.3 M sodium chloride. The arylsulfatase A activity obtained from normal leukocytes and fibroblasts is linear for the initial 10 minutes of the reaction, is stimulated 3-fold by 6 mM lead acetate and inhibited 80% by 0.24 mM silver nitrate. After separation with CM-32, the arylsulfatase B activity is stimulated 3-fold by Triton X-100 (0.1%). Arylsulfatase A but not arylsulfatase B is destroyed by heat (60 degrees). Both leukocyte and fibroblast arylsulfatase A activity was reduced to 11% of control values in metachromatic leukodystrophy. Essentially no arylsulfatase B activity was detected in cells from patients with Maroteaux-Lamy syndrome. Metachromatic leukodystrophy heterozygotes but not Maroteaux-Lamy syndrome heterozygotes can also be distinguished by this method. A heat inactivation technique utilizing the differential thermal stabilities of the two enzymes for diagnosis of patients with Marotezux-Lamy syndrome is also described. The advantages of these 4-methylumbelliferyl sulfate assay procedures over the p-nitrocatechol sulfate method of assay are greater sensitivity, selectivity for the desired enzyme and potential for use in large scale testing.

The metabolism of foreign compounds in the cestode, Moniezia expansa, and the nematode, Ascaris lumbricoides var suum

1. The ability of the cestode Moniezia expansa and the nematode Ascaris lumbricoides var suum to metabolize foreign compounds has been assessed. 2. Both species were unable to oxidase aldrin, aniline, biphenyl, butylbenzene and nitrobenzene or to demethylate aminopyrine, and 4-nitroanisole. 3. M. expansa and A. lumbricoides var suum readily induced 4-nitroanisole, nitrobenzene, 4-nitrobenzoic acid and 4-nitrophenol to the corresponding amines. Azobenzene, dimethylaminoazobenzene, and 1,2-dimethyl-4-(4-carboxyphenylazo)-5-hydroxybenzene were also reduced. 4. Hydrolysis of esters, acetanilide, acetylsalicylic acid, aryl sulphates and aryl phosphates took place readily. However, beta-glucuronides were not hydrolysed. 5. The following reactions were not detected in either species: phosphate, sulphate, beta-glucuronide or beta-glycoside conjugation of phenolic compounds; acetylation of amino compounds, or the formation of glycine conjugates with 4-aminobenzoic acid or benzoic acid. 6. Male nematodes showed a higher rate of drug metabolism than female nematodes.

Electrophoresis of arylsulfatase from normal individuals and patients with metachromatic leukodystrophy

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