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Kas-Deelen AM, Bakker WW, Olinga P, Visser J, de Maar EF, van Son WJ, The TH, Harmsen MC. Cytomegalovirus infection increases the expression and activity of ecto-ATPase (CD39) and ecto-5'nucleotidase (CD73) on endothelial cells. FEBS Lett 2001; 491:21-5. [PMID: 11226411 DOI: 10.1016/s0014-5793(01)02085-3] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We describe enhanced expression and enzymatic activity of ecto-ATPase and ecto-5'nucleotidase on CMV infected endothelial cells as compared to uninfected cells. These ectoenzymes play a major role in modulation of platelet activation and aggregation. Furthermore, adenosine has a modulatory effect upon inflammation. Addition of ATP, ADP or AMP to cultures of CMV infected or uninfected endothelial cells revealed increased turnover of AMP in CMV infected endothelial cells. In addition, the superoxide production by stimulated polymorphonuclear cells was inhibited in the presence of CMV infected endothelial cells as compared to uninfected cells, probably due to the enhanced activity of ecto-5'nucleotidase and associated to production of adenosine.
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Parenicová L, Skouboe P, Frisvad J, Samson RA, Rossen L, ten Hoor-Suykerbuyk M, Visser J. Combined molecular and biochemical approach identifies Aspergillus japonicus and Aspergillus aculeatus as two species. Appl Environ Microbiol 2001; 67:521-7. [PMID: 11157212 PMCID: PMC92616 DOI: 10.1128/aem.67.2.521-527.2001] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We examined nine Aspergillus japonicus isolates and 10 Aspergillus aculeatus isolates by using molecular and biochemical markers, including DNA sequences of the ITS1-5.8S rRNA gene-ITS2 region, restriction fragment length polymorphisms (RFLP), and secondary-metabolite profiles. The DNA sequence of the internal transcribed spacers (ITS1 and ITS2) and the 5.8S rRNA gene could not be used to distinguish between A. japonicus and A. aculeatus but did show that these two taxa are more closely related to each other than to other species of black aspergilli. Aspergillus niger pyruvate kinase (pkiA) and pectin lyase A (pelA) and Agaricus bisporus 28S rRNA genes, which were used as probes in the RFLP analysis, revealed clear polymorphism between these two taxa. The A. niger pkiA and pelA probes placed six strains in an A. japonicus group and 12 isolates in an A. aculeatus group, which exhibited intraspecific variation when they were probed with the pelA gene. The secondary-metabolite profiles supported division of the isolates into the two species and differed from those of other black aspergilli. The strains classified as A. japonicus produced indole alkaloids and a polar metabolite, while the A. aculeatus isolates produced neoxaline, okaramins, paraherquamidelike compounds, and secalonic acid. A. aculeatus CBS 114.80 showed specific RFLP patterns for all loci examined. The secondary-metabolite profile of strain CBS 114.80 also differed from those of A. japonicus and A. aculeatus. Therefore, this strain probably represents a third taxon. This study provides unambiguous criteria for establishing the taxonomic positions of isolates of black aspergilli, which are important in relation to industrial use and legal protection of these organisms.
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Fillinger S, Ruijter G, Tamás MJ, Visser J, Thevelein JM, d'Enfert C. Molecular and physiological characterization of the NAD-dependent glycerol 3-phosphate dehydrogenase in the filamentous fungus Aspergillus nidulans. Mol Microbiol 2001; 39:145-57. [PMID: 11123696 DOI: 10.1046/j.1365-2958.2001.02223.x] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
In filamentous fungi, glycerol biosynthesis has been proposed to play an important role during conidiospore germination and in response to a hyperosmotic shock, but little is known about the genes involved. Here, we report on the characterization of the major Aspergillus nidulans glycerol 3-phosphate dehydrogenase (G3PDH)-encoding gene, gfdA. G3PDH is responsible for the conversion of dihydroxyacetone phosphate (DHAP) into glycerol 3-phosphate (G3P), which is subsequently converted into glycerol by an as yet uncharacterized phosphatase. Inactivation of gfdA does not abolish glycerol biosynthesis, showing that the other pathway from DHAP, via dihydroxyacetone (DHA), to glycerol is also functional in A. nidulans. The gfdA null mutant displays reduced G3P levels and an osmoremediable growth defect on various carbon sources except glycerol. This growth defect is associated with an abnormal hyphal morphology that is reminiscent of a cell wall defect. Furthermore, the growth defect at low osmolarity is enhanced in the presence of the chitin-interacting agent calcofluor and the membrane-destabilizing agent sodium dodecyl sulphate (SDS). As inactivation of gfdA has no impact on phospholipid biosynthesis or glycolytic intermediates levels, as might be expected from reduced G3P levels, a previously unsuspected link between G3P and cell wall integrity is proposed to occur in filamentous fungi.
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van den Brand MGJ, van Deursen A, Heering J, de Jong HA, de Jonge M, Kuipers T, Klint P, Moonen L, Olivier PA, Scheerder J, Vinju JJ, Visser E, Visser J. The Asf+Sdf Meta-environment: A Component-Based Language Development Environment. LECTURE NOTES IN COMPUTER SCIENCE 2001. [DOI: 10.1007/3-540-45306-7_26] [Citation(s) in RCA: 97] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Benen JA, Kester HC, Parenicová L, Visser J. Characterization of Aspergillus niger pectate lyase A. Biochemistry 2000; 39:15563-9. [PMID: 11112543 DOI: 10.1021/bi000693w] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The Aspergillus niger plyA gene encoding pectate lyase A (EC 4.2.99. 3) was cloned from a chromosomal lambda(EMBL4) library using the Aspergillus nidulans pectate lyase encoding gene [Dean, R. A., and Timberlake, W. E. (1989) Plant Cell 1, 275-284] as a probe. The plyA gene was overexpressed using a promoter fusion with the A. niger pyruvate kinase promoter. Purification of the recombinant pectate lyase A resulted in the identification of two enzyme forms of which one appeared to be N-glycosylated and the other appeared to be free of N-glycosylation. The two enzyme forms showed identical specific activities. The N-glycosylation free pectate lyase A was further characterized with respect to product formation on polygalacturonic acid (alpha-1,4 linked D-galacturonic acid) and mode of action on oligogalacturonides of degree of polymerization 2-8. The bond cleavage frequencies for tetra-, penta-, and hexagalacturonides were studied as a function of [CaCl(2)]. The bond cleavage frequencies changed in a [CaCl(2)]-dependent way for penta- and hexagalacturonide. Kinetic studies using tetra- and hexagalacturonide revealed a strong sigmoidal [CaCl(2)]-dependent relation. The role of Ca(2+) ions in substrate binding is discussed.
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de Kleijn ED, de Groot R, Lafeber AB, Labadie J, van Limpt KC, Visser J, Berbers GA, van Alphen L, Rümke HC. Immunogenicity and safety of monovalent p1.7(h),4 meningococcal outer membrane vesicle vaccine in toddlers: comparison of two vaccination schedules and two vaccine formulations. Vaccine 2000; 19:1141-8. [PMID: 11137250 DOI: 10.1016/s0264-410x(00)00320-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The safety and immunogenicity of two PorA-based meningococcal outer membrane vesicle (OMV) vaccines against the P1.4 serosubtype adsorbed with AlPO(4) or Al(OH)(3) were studied in 134 toddlers. Vaccinations were given three times with an interval of 3-6 weeks or twice with an interval of 6-10 weeks. A vaccination was repeated after 20-40 weeks. Pre- and post-immunization sera were tested for bactericidal activity against an isogenic strain expressing P1.7(h), 4 PorA. Both meningococcal OMV vaccines were well tolerated. The percentage of children with a fourfold increase in bactericidal activity was 96% (AlPO(4)-adjuvated vaccine/2+1 schedule), 100% (AlPO(4)-adjuvated vaccine/3+1 schedule), 93% (Al(OH)(3)-adjuvated vaccine/2+1 schedule) and 97% (Al(OH)(3)-adjuvated vaccine/3+1 schedule). Adsorption with AlPO(4) makes the OMV vaccine more immunogenic than adsorption with Al(OH)(3). Bactericidal activity was highest after the 3+1 schedule, although the response shortly after the primary series was higher in the two-dose priming group.
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Decker CH, Visser J, Schreier P. beta-glucosidases from five black Aspergillus species: study of their physico-chemical and biocatalytic properties. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2000; 48:4929-36. [PMID: 11052758 DOI: 10.1021/jf000434d] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Five black Aspergillus strains (A. aculeatus, A. foetidus, A. japonicus, A. niger, and A. tubingensis) were cultivated on crude wheat arabinoxylan as the carbon source under defined pH, temperature, and oxygen conditions. Protein and beta-glucosidase content differed remarkably within the obtained culture filtrates, of which eleven beta-glucosidases were isolated. Seven beta-glucosidases were purified to apparent electrophoretic homogeneity using anion-exchange and gel-permeation chromatography. They were found to be acidic proteins and most of them appeared to be glycoproteins with a molecular mass between 93 and 142 kDa. Classification of the beta-glucosidases into four groups (I-A, I-B, II, and III) is suggested according to their physicochemical and biocatalytic properties. The major beta-glucosidases were assigned to groups I-A and I-B, the minor beta-glucosidases to groups II and III, comprising acid-tolerant and glucose-tolerant enzymes, respectively.
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Pagès S, Heijne WH, Kester HC, Visser J, Benen JA. Subsite mapping of Aspergillus niger endopolygalacturonase II by site-directed mutagenesis. J Biol Chem 2000; 275:29348-53. [PMID: 10893426 DOI: 10.1074/jbc.m910112199] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
To assess the subsites involved in substrate binding in Aspergillus niger endopolygalacturonase II, residues located in the potential substrate binding cleft stretching along the enzyme from the N to the C terminus were subjected to site-directed mutagenesis. Mutant enzymes were characterized with respect to their kinetic parameters using polygalacturonate as a substrate and with respect to their mode of action using oligogalacturonates of defined length (n = 3-6). In addition, the effect of the mutations on the hydrolysis of pectins with various degrees of esterification was studied. Based on the results obtained with enzymes N186E and D282K it was established that the substrate binds with the nonreducing end toward the N terminus of the enzyme. Asn(186) is located at subsite -4, and Asp(282) is located at subsite +2. The mutations D183N and M150Q, both located at subsite -2, affected catalysis, probably mediated via the sugar residue bound at subsite -1. Tyr(291), located at subsite +1 and strictly conserved among endopolygalacturonases appeared indispensable for effective catalysis. The mutations E252A and Q288E, both located at subsite +2, showed only slight effects on catalysis and mode of action. Tyr(326) is probably located at the imaginary subsite +3. The mutation Y326L affected the stability of the enzyme. For mutant E252A, an increased affinity for partially methylesterified substrates was recorded. Enzyme N186E displayed the opposite behavior; the specificity for completely demethylesterified regions of substrate, already high for the native enzyme, was increased. The origin of the effects of the mutations is discussed.
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Powell AL, van Kan J, ten Have A, Visser J, Greve LC, Bennett AB, Labavitch JM. Transgenic expression of pear PGIP in tomato limits fungal colonization. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2000; 13:942-50. [PMID: 10975651 DOI: 10.1094/mpmi.2000.13.9.942] [Citation(s) in RCA: 102] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Transgenic tomato plants expressing the pear fruit polygalacturonase inhibitor protein (pPGIP) were used to demonstrate that this inhibitor of fungal pathogen endopolygalacturonases (endo-PGs) influences disease development. Transgenic expression of pPGIP resulted in abundant accumulation of the heterologous protein in all tissues and did not alter the expression of an endogenous tomato fruit PGIP (tPGIP). The pPGIP protein was detected, as expected, in the cell wall protein fraction in all transgenic tissues. Despite differential glycosylation in vegetative and fruit tissues, the expressed pPGIP was active in both tissues as an inhibitor of endo-PGs from Botrytis cinerea. The growth of B. cinerea on ripe tomato fruit expressing pPGIP was reduced, and tissue breakdown was diminished by as much as 15%, compared with nontransgenic fruit In transgenic leaves, the expression of pPGIP reduced lesions of macerated tissue approximately 25%, a reduction of symptoms of fungal growth similar to that observed with a B. cinerea strain in which a single endo-PG gene, Bcpg1, had been deleted (A. ten Have, W. Mulder, J. Visser, and J. A. L. van Kan, Mol. Plant-Microbe Interact. 11:1009-1016, 1998). Heterologous expression of pPGIP has demonstrated that PGIP inhibition of fungal PGs slows the expansion of disease lesions and the associated tissue maceration.
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de Vries RP, Kester HC, Poulsen CH, Benen JA, Visser J. Synergy between enzymes from Aspergillus involved in the degradation of plant cell wall polysaccharides. Carbohydr Res 2000; 327:401-10. [PMID: 10990025 DOI: 10.1016/s0008-6215(00)00066-5] [Citation(s) in RCA: 169] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Synergy in the degradation of two plant cell wall polysaccharides, water insoluble pentosan from wheat flour (an arabinoxylan) and sugar beet pectin, was studied using several main-chain cleaving and accessory enzymes. Synergy was observed between most enzymes tested, although not always to the same extent. Degradation of the xylan backbone by endo-xylanase and beta-xylosidase was influenced most strongly by the action of alpha-L-arabinofuranosidase and arabinoxylan arabinofuranohydrolase resulting in a 2.5-fold and twofold increase in release of xylose, respectively. Ferulic acid release by feruloyl esterase A and 4-O-methyl glucuronic acid release by alpha-glucuronidase depended largely on the degradation of the xylan backbone by endo-xylanase but were also influenced by other enzymes. Degradation of the backbone of the pectin hairy regions resulted in a twofold increase in the release of galactose by beta-galactosidase and endo-galactanase but did not significantly influence the arabinose release by arabinofuranosidase and endo-arabinase. Ferulic acid release from sugar beet pectin by feruloyl esterase A was affected most strongly by the presence of other accessory enzymes.
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186
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Herron SR, Benen JA, Scavetta RD, Visser J, Jurnak F. Structure and function of pectic enzymes: virulence factors of plant pathogens. Proc Natl Acad Sci U S A 2000; 97:8762-9. [PMID: 10922032 PMCID: PMC34009 DOI: 10.1073/pnas.97.16.8762] [Citation(s) in RCA: 140] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The structure and function of Erwinia chrysanthemi pectate lysase C, a plant virulence factor, is reviewed to illustrate one mechanism of pathogenesis at the molecular level. Current investigative topics are discussed in this paper.
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187
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Willats WG, Limberg G, Buchholt HC, van Alebeek GJ, Benen J, Christensen TM, Visser J, Voragen A, Mikkelsen JD, Knox JP. Analysis of pectic epitopes recognised by hybridoma and phage display monoclonal antibodies using defined oligosaccharides, polysaccharides, and enzymatic degradation. Carbohydr Res 2000; 327:309-20. [PMID: 10945679 DOI: 10.1016/s0008-6215(00)00039-2] [Citation(s) in RCA: 177] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The structure of epitopes recognised by anti-pectin monoclonal antibodies (mAbs) has been investigated using a series of model lime-pectin samples with defined degrees and patterns of methyl esterification, a range of defined oligogalacturonides and enzymatic degradation of pectic polysaccharides. In immuno-dot-assays, the anti-homogalacturonan (HG) mAbs JIM5 and JIM7 both bound to samples with a wide range of degrees of methyl esterification in preference to fully de-esterified samples. In contrast, the anti-HG phage display mAb PAM1 bound most effectively to fully de-esterified pectin. In competitive inhibition ELISAs using fully methyl-esterified or fully de-esterified oligogalacturonides with 3-9 galacturonic acid residues, JIM5 bound weakly to a fully de-esterified nonagalacturonide but JIM7 did not bind to any of the oligogalacturonides tested. Therefore, optimal JIM5 and JIM7 binding occurs where specific but undefined methyl-esterification patterns are present on HG domains, although fully de-esterified HG samples contain sub-optimal JIM5 epitopes. The persistence of mAb binding to epitopes in pectic antigens, with 41% blockwise esterification (P41) and 43% random esterification (F43) subject to fragmentation by endo-polygalacturonase II (PG II) and endo-pectin lyase (PL), was also studied. Time course analysis of PG II digestion of P41 revealed that JIM5 epitopes were rapidly degraded, but a low level of PAM1 and JIM7 epitopes existed even after extensive digestion, indicating that some HG domains were more resistant to cleavage by PG II. The chromatographic separation of fragments produced by the complete digestion of P41 by pectin lyase indicated that a very restricted population of fragments contained the PAM1 epitope while a (1-->4)-beta-D-galactan epitope occurring on the side chains of pectic polysaccharides was recovered in a broad range of fractions.
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188
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Moolenaar F, Meijler WJ, Frijlink HW, Visser J, Proost JH. Clinical efficacy, safety and pharmacokinetics of a newly developed controlled release morphine sulphate suppository in patients with cancer pain. Eur J Clin Pharmacol 2000; 56:219-23. [PMID: 10952476 DOI: 10.1007/s002280000133] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
OBJECTIVE To compare the efficacy, safety and pharmacokinetics of a newly developed controlled-release suppository (MSR) with MS Contin tablets (MSC) in cancer patients with pain. METHODS In a double-blind, randomised, two-way cross-over trial, 25 patients with cancer pain were selected with a morphine (M) demand of 30 mg every 12 h. Patients were divided into two groups. Group 1 received active MSC (30 mg) and placebo MSR, followed by placebo MSC and active MSR (30 mg) each for a period of 5 days. Group 2 started with active MSR and placebo MSC, followed by active MSC and placebo MSR, each for a period of 5 days. Blood for determination of plasma concentration of morphine (M) and its 3- and 6-glucuronides (M3G, M6G) was collected, and area under the plasma concentration-time curve (AUC)0-12 h, peak plasma concentration (Cmax), time to reach Cmax (tmax), and CO and C12 of M, M6G and M3G were determined on day 5 and day 10. Intensity of pain experienced by each patient was assessed every 2 h on a 0-10 scale, while side effects and rescue medication were recorded. RESULTS Twenty patients (ten patients in each group) completed the study. A pronounced inter-patient variability in plasma concentrations of M, M3G and M6G was observed after administration of both forms. Apart from the C0 and C12, no significant differences in AUC0-12 h, tmax and Cmax of morphine between the rectal and oral route of administration were found. In the case of the metabolites, it was found that AUC0-12 h and Cmax of M6G, and AUC0-12 h, Cmax, C0 and C12 of M3G after rectal administration were significantly lower than after oral administration. However, apart from the tmax of M6G, none of the pharmacokinetic parameters of M, M6G or M3G met the criteria for bioequivalence. There were no significant (P = 0.44) differences in pain intensity score between the oral and rectal forms within the two groups, regardless of the treatment sequence. No treatment differences in nausea, sedation or the demand on escape medication (acetaminophen tablets) between the rectal and oral forms were observed. CONCLUSION The newly developed controlled-release M suppository is safe and effective and may be a useful alternative for oral morphine administration in patients with cancer pain.
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Airapetian A, Akopov N, Amarian M, Aschenauer EC, Avakian H, Avakian R, Avetissian A, Avetissian E, Bains B, Baumgarten C, Beckmann M, Belostotski S, Belz JE, Benisch T, Bernreuther S, Bianchi N, Blouw J, Böttcher H, Borissov A, Bouwhuis M, Brack J, Brauksiepe S, Braun B, Bray B, Brons S, Brückner W, Brüll A, Bruins EEW, Bulten HJ, Capitani GP, Carter P, Chumney P, Cisbani E, Court GR, Dalpiaz PF, De Sanctis E, De Schepper D, Devitsin E, de Witt Huberts PKA, Di Nezza P, Düren M, Dvoredsky A, Elbakian G, Ely J, Fantoni A, Fechtchenko A, Ferstl M, Fiedler K, Filippone BW, Fischer H, Fox B, Franz J, Frullani S, Funk MA, Gärber Y, Gao H, Garibaldi F, Gavrilov G, Geiger P, Gharibyan V, Golendukhin A, Graw G, Grebeniouk O, Green PW, Greeniaus LG, Grosshauser C, Guidal M, Gute A, Gyurjyan V, Haas JP, Haeberli W, Hansen JO, Hartig M, Hasch D, Häusser O, Heinsius FH, Henderson R, Henoch M, Hertenberger R, Holler Y, Holt RJ, Hoprich W, Ihssen H, Iodice M, Izotov A, Jackson HE, Jgoun A, Kaiser R, Kinney E, Kisselev A, Kitching P, Kobayashi H, Koch N, Königsmann K, Kolstein M, Kolster H, Korotkov V, Korsch W, Kozlov V, Kramer LH, Krivokhijine VG, Kurisuno M, Kyle G, Lachnit W, Lenisa P, Lorenzon W, Makins NCR, Martens FK, Martin JW, Masoli F, Mateos A, McAndrew M, McIlhany K, McKeown RD, Meissner F, Menden F, Metz A, Meyners N, Mikloukho O, Miller CA, Miller MA, Milner R, Most A, Muccifora V, Mussa R, Nagaitsev A, Naryshkin Y, Nathan AM, Neunreither F, Niczyporuk M, Nowak WD, Nupieri M, Oganessyan KA, O'Neill TG, Openshaw R, Ouyang J, Owen BR, Papavassiliou V, Pate SF, Pitt M, Potashov S, Potterveld DH, Rakness G, Reali A, Redwine R, Reolon AR, Ristinen R, Rith K, Rossi P, Rudnitsky S, Ruh M, Ryckbosch D, Sakemi Y, Savin I, Scarlett C, Schäfer A, Schmidt F, Schmitt H, Schnell G, Schüler KP, Schwind A, Seibert J, Shibata TA, Shibatani K, Shin T, Shutov V, Simani C, Simon A, Sinram K, Slavich P, Spengos M, Steffens E, Stenger J, Stewart J, Stoesslein U, Sutter M, Tallini H, Taroian S, Terkulov A, Teryaev O, Thomas E, Tipton B, Tytgat M, Urciuoli GM, van den Brand JFJ, van der Steenhoven G, van de Vyver R, van Hunen JJ, Vetterli MC, Vikhrov V, Vincter MG, Visser J, Volk E, Wander W, Wendland J, Williamson SE, Wise T, Woller K, Yoneyama S, Zohrabian H. Evidence for a single-spin azimuthal asymmetry in semi-inclusive pion electroproduction. PHYSICAL REVIEW LETTERS 2000; 84:4047-4051. [PMID: 10990607 DOI: 10.1103/physrevlett.84.4047] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/1999] [Indexed: 05/23/2023]
Abstract
Single-spin asymmetries for semi-inclusive pion production in deep-inelastic scattering have been measured for the first time. A significant target-spin asymmetry of the distribution in the azimuthal angle straight phi of the pion relative to the lepton scattering plane was formed for pi(+) electroproduction on a longitudinally polarized hydrogen target. The corresponding analyzing power in the sinstraight phi moment of the cross section is 0.022+/-0.005+/-0.003. This result can be interpreted as the effect of terms in the cross section involving chiral-odd spin distribution functions in combination with a chiral-odd fragmentation function that is sensitive to the transverse polarization of the fragmenting quark.
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Biely P, Vrsanská M, Visser J. Inverting character of alpha-glucuronidase A from Aspergillus tubingensis. BIOCHIMICA ET BIOPHYSICA ACTA 2000; 1474:360-4. [PMID: 10779688 DOI: 10.1016/s0304-4165(00)00029-5] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Alpha-glucuronidase A from Aspergillus tubingensis was found to be capable of liberating 4-O-methyl-D-glucuronic acid (MeGlcA) only from those beechwood glucuronoxylan fragments in which the acid is attached to the non-reducing terminal xylopyranosyl residue. Reduced aldotetrauronic acid, 4-O-methyl-D-glucuronosyl-alpha-1,2-D-xylopyranosyl-beta-1,4-xylopyranosyl-beta-1,4-xylitol, was found to be a suitable substrate to follow the stereochemical course of the hydrolytic reaction catalyzed by the purified enzyme. The configuration of the liberated MeGlcA was followed in a D(2)O reaction mixture by (1)H-NMR spectroscopy. It was unambiguously established that MeGlcA was released from the substrate as its beta-anomer from which the alpha-anomer was formed on mutarotation. This result represents the first experimental evidence for the inverting character of a microbial alpha-glucuronidase, a member of glycosyl hydrolase family 67 (EC 3.1.1.139).
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191
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Visser J, Kroeze JH, Kamps WA, Bijleveld CM. Testing taste sensitivity and aversion in very young children: development of a procedure. Appetite 2000; 34:169-76. [PMID: 10744906 DOI: 10.1006/appe.1999.0306] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Taste perception in 45 3- to 6-year-old children was tested using procedures specifically designed for this age group. Detection thresholds for sucrose and urea were measured by a staircase method and aversion to urea was assessed hedonically, using drawings of facial expressions. All children understood the task and could perform the necessary actions. A subgroup of 20 children participated in a second measurement after a mean interval of 9.5 days: there was a satisfactory degree of stability between the sessions. However, a third measurement, on a subgroup of 13 children after a somewhat longer interval, showed a marked drop in the stability of the urea thresholds. This drop was thought to arise from a decrease in the children's motivation, leading to increased distractibility. Mean threshold estimates were 31 mmol/l for sucrose detection, 59 mmol/l for urea detection and 134 mmol/l for urea aversion, but some children were extremely sensitive to the taste of urea. The findings show that it is possible to study taste perception in very young children if their age is taken into consideration in developing the test procedure. Valid data can be obtained if the procedures are short, easy to understand and intrinsically motivating.
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Hasper AA, Visser J, de Graaff LH. The Aspergillus niger transcriptional activator XlnR, which is involved in the degradation of the polysaccharides xylan and cellulose, also regulates D-xylose reductase gene expression. Mol Microbiol 2000; 36:193-200. [PMID: 10760176 DOI: 10.1046/j.1365-2958.2000.01843.x] [Citation(s) in RCA: 107] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Screening of an Aspergillus niger differential cDNA library, constructed by subtracting cDNA fragments of a xlnR loss-of-function mutant from wild-type cDNA fragments, resulted in the cloning of the gene encoding D-xylose reductase (xyrA). Northern blot analysis using an A. niger wild-type strain, a xlnR multiple-copy strain and a xlnR loss-of-function mutant confirmed that the xyrA gene is regulated by XlnR, the transcriptional activator of the xylanolytic enzyme system in A. niger. D-xylose reductase catalyses the NADPH-dependent reduction of D-xylose to xylitol, which is the first step in D-xylose catabolism in fungi. Until now, XlnR was shown to control the transcription of genes encoding extracellular hydrolytic enzymes involved in cellulose and xylan degradation. In the present study, we show that A. niger is able to harmonize its sugar metabolism and extracellular xylan degradation via XlnR by regulating the expression of XyrA.
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193
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Ruijter GJ, Panneman H, Xu D, Visser J. Properties of Aspergillus niger citrate synthase and effects of citA overexpression on citric acid production. FEMS Microbiol Lett 2000; 184:35-40. [PMID: 10689162 DOI: 10.1111/j.1574-6968.2000.tb08986.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Using a combination of dye adsorption and affinity elution we purified Aspergillus niger citrate synthase to homogeneity using a single column and characterised the enzyme. An A. niger citrate synthase cDNA was isolated by immunological screening and used to clone the corresponding citA gene. The deduced amino acid sequence showed high similarity to other fungal citrate synthases. After processing upon mitochondrial import, the calculated M(r) of A. niger citrate synthase is 48501, which agrees well with the estimated molecular mass of the purified protein (48 kDa). In addition to an N-terminal mitochondrial import signal, a peroxisomal target sequence (AKL) was found at the C-terminus of the protein. Whether both signals are functional in vivo is not clear. Strains overexpressing citA were made by transformation and cultured under citric acid-producing conditions. Up to 11-fold overproduction of citrate synthase did not increase the rate of citric acid production by the fungus, suggesting that citrate synthase contributes little to flux control in the pathway involved in citric acid biosynthesis by a non-commercial strain.
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194
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Kester HC, Benen JA, Visser J, Warren ME, Orlando R, Bergmann C, Magaud D, Anker D, Doutheau A. Tandem mass spectrometric analysis of aspergillus niger pectin methylesterase: mode of action on fully methyl-esterified oligogalacturonates. Biochem J 2000; 346 Pt 2:469-74. [PMID: 10677368 PMCID: PMC1220875] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
Abstract
The substrate specificity and the mode of action of Aspergillus niger pectin methylesterase (PME) was determined using both fully methyl-esterified oligogalacturonates with degrees of polymerization (DP) 2-6 and chemically synthesized monomethyl trigalacturonates. The enzymic activity on the different substrates and a preliminary characterization of the reaction products were performed by using high-performance anion-exchange chromatography at neutral pH. Electrospray ionization tandem MS (ESI-MS/MS) was used to localize the methyl esters on the (18)O-labelled reaction products during the course of the enzymic reaction. A. niger PME is able to hydrolyse the methyl esters of fully methyl-esterified oligogalacturonates with DP 2, and preferentially hydrolyses the methyl esters located on the internal galacturonate residues, followed by hydrolysis of the methyl esters towards the reducing end. This PME is unable to hydrolyse the methyl ester of the galacturonate moiety at the non-reducing end.
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195
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Fitzgerald SD, Visser J, Mosser T, Render AE. Clinical challenge. Acute necrotizing enteritis with microabscesses due to Yersinia pseudotuberculosis. J Zoo Wildl Med 2000; 31:129-30. [PMID: 10884139 DOI: 10.1638/1042-7260(2000)031[0129:cc]2.0.co;2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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196
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Parenicová L, Kester HC, Benen JA, Visser J. Characterization of a novel endopolygalacturonase from Aspergillus niger with unique kinetic properties. FEBS Lett 2000; 467:333-6. [PMID: 10675564 DOI: 10.1016/s0014-5793(00)01173-x] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
We isolated and characterized a new type of endopolygalacturonase (PG)-encoding gene, pgaD, from Aspergillus niger. The primary structure of PGD differs from that of other A. niger PGs by a 136 amino acid residues long N-terminal extension. Biochemical analysis demonstrated extreme processive behavior of the enzyme on oligomers longer than five galacturonate units. Furthermore, PGD is the only A. niger PG capable of hydrolyzing di-galacturonate. It is tentatively concluded that the enzyme is composed of four subsites. The physiological role of PGD is discussed.
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197
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Parenicová L, Benen JA, Kester HC, Visser J. pgaA and pgaB encode two constitutively expressed endopolygalacturonases of Aspergillus niger. Biochem J 2000; 345 Pt 3:637-44. [PMID: 10642523 PMCID: PMC1220799] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
Abstract
The nucleotide sequence data for pgaA and pgaB have been deposited with the EMBL, GenBank and DDBJ Databases under accession numbers Y18804 and Y18805 respectively. pgaA and pgaB, two genes encoding endopolygalacturonases (PGs, EC 3.2.1.15) A and B, were isolated from a phage genomic library of Aspergillus niger N400. The 1167 bp protein coding region of the pgaA gene is interrupted by one intron, whereas the 1234 bp coding region of the pgaB gene contains two introns. The corresponding proteins, PGA and PGB, consist of 370 and 362 amino acid residues respectively. Northern-blot analysis revealed that pgaA- and pgaB-specific mRNA accumulate in mycelia grown on sucrose. mRNAs are also present upon transfer to media containing D-galacturonic acid and pectin. Recombinant PGA and PGB were characterized with respect to pH optimum, activity on polygalacturonic acid, and mode of action and kinetics on oligogalacturonates of different chain length (n=3-7). At their pH optimum the specific activities in a standard assay for PGA (pH 4.2) and PGB (pH 5.0) were 16.5 mu+kat.mg(-1) and 8.3 mu+kat.mg(-1) respectively. Product progression analysis, using polygalacturonate as a substrate, revealed a random cleavage pattern for both enzymes and indicated processive behaviour for PGA. This result was confirmed by analysis of the mode of action using oligogalacturonates. Processivity was observed when the degree of polymerization of the substrate exceeded 6. Using pectins of various degrees of methyl esterification, it was shown that PGA and PGB both preferred partially methylated substrates.
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198
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Wubben JP, ten Have A, van Kan JA, Visser J. Regulation of endopolygalacturonase gene expression in Botrytis cinerea by galacturonic acid, ambient pH and carbon catabolite repression. Curr Genet 2000; 37:152-7. [PMID: 10743572 DOI: 10.1007/s002940050022] [Citation(s) in RCA: 89] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The phytopathogenic fungus Botrytis cinerea produces a set of endopolygalacturonases (endoPGs) which are involved in the enzymatic degradation of pectin in plant cell walls. The endoPG-encoding genes of B. cinerea are differentially expressed when the fungus is grown in liquid culture on different carbon sources. A basic constitutive expression level was observed for two genes, Bcpg1 and Bcpg2, which encode basic isozymes. Galacturonic acid was shown to induce the expression of Bcpg4 and Bcpg6. Low pH of the culture medium resulted in induced expression of the Bcpg3 gene. Expression of the Bcpg5 gene was inducible; however the inducing factors could not be identified. Finally, galacturonic acid-induced expression of the Bcpg4 gene was repressed by the presence of more-favourable carbon sources, such as glucose.
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Abstract
The Kinaesthetic Sensitivity Test (KST) was used to measure the development of kinaesthetic acuity in adolescent boys. Thirty boys were tested longitudinally, at intervals of 6 months, between the ages of 11 1/2 and 14 years. A second group of 20 boys was tested at the ages of 14 and 16 1/2 years. The findings were compared with existing normative data on 5- to 12-year-old children and young adults, and they indicated improvement in kinaesthetic acuity with age. Although the age effect is statistically significant only in the older group, confidence intervals show that the rate of improvement in both groups is comparable to improvement between the ages of 5 and 12 years. The reliability of the test is rather poor. The conclusion is that kinaesthetic development continues throughout adolescence. Further, development is quite robust and detectable even with a fairly unreliable measurement instrument. However, individual assessments should be interpreted with caution.
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