| in vitro evaluation of 2,4-dihydroxythiobenzanilides against various moulds. | the antimycotic potency of 2,4-dihydroxythiobenzanilide derivatives was tested. the mic assessments by an agar dilution method were used for the estimation of potential activity in vitro against the four mould strains: scopulariopsis brevicalis, aspergillus niger, aspergillus fumigatus and penicillium sp. the strongest fungistatic activity was observed for 3'-fluoro-derivative (mic 7.82 microg/ml). it was stated that the inhibition action of these compounds depends mainly on lipophilicity of mol ... | 2001 | 11384846 |
| [spatial peculiarities of rhizoplane colonization by microscopic fungi]. | spatial peculiarities in the colonization of the tomato, cucumber, and barley rhizoplanes by microscopic fungi were studied. the apical zone of roots was colonized with a limited number of r strategists (the order mucorales, fusarium sp., aspergillus niger, and mycelia sterilia). the fungal population of the root hairs and the basal zone of roots was 2- to 3-fold more dense due to the prevalence of k strategists. fusaria, fusarium oxysporum in particular, colonized roots in earlier terms than th ... | 2001 | 11386053 |
| molecular cloning and characterization of the fructooligosaccharide-producing beta-fructofuranosidase gene from aspergillus niger atcc 20611. | the fopa gene encoding a fructooligosaccharide-producing beta-fructofuranosidase was isolated from aspergillus niger atcc 20611. the primary structure deduced from the nucleotide sequence showed considerable similarity to those of two other beta-fructofuranosidases from a. niger, but the fopa gene product had several amino acid insertions and an extra c-terminal polypeptide consisting of 38 amino acids that could not be found in the two others. we could successfully express the fopa gene in s. c ... | 2001 | 11388451 |
| recombinant microdochium nivale carbohydrate oxidase and its application in an amperometric glucose sensor. | biosensors containing recombinant carbohydrate oxidase from microdochium nivale (rmno) were developed by means of either chemically modified carbon paste or graphite electrode. 1-(n,n-dimethylamine)-4-(4-morpholine)benzene (amb) and 1,1'-dimethylferrocene (dmfc) have been used as mediators. the biosensors showed a linear calibration graph up to 18 mm of glucose when operated at 0.04-0.36 v versus a saturated calomel electrode. almost no change was detected in the sensitivity of the biosensors at ... | 2001 | 11390220 |
| allergic bronchopulmonary mycosis in patients with asthma: period prevalence at a university hospital in saudi arabia. | allergic bronchopulmonary mycosis (abpm) is a known complication of asthma and can result in progressive lung damage, respiratory failure and death. asthma is a common disease in saudi arabia and until now the prevalence of abpm has not been investigated. the aim of this study was to estimate the period prevalence of abpm due to aspergillus and candida in patients with asthma. the setting was an outpatient pulmonary clinic at a university hospital in the central region of saudi arabia. two hundr ... | 2001 | 11392574 |
| preparation of levoglucosan by pyrolysis of cellulose and its citric acid fermentation. | levoglucosan (lg), 1,6-anhydro-beta-d-glucopyranose, was produced by pyrolysis of cellulose. a response surface method was used to optimize the reaction parameters: x1, temperature; x2, time required for heating cellulose from room temperature to the designed pyrolysis temperature; and x3, vacuum, and a box-behnken design was employed for this purpose. the optimal temperature and time were found to be 388 degrees c and 26.2 min by fixing the vacuum at 1 mm hg. the levoglucosan prepared was ferme ... | 2001 | 11396909 |
| main glucosidase conversion products of the gluco-alkaloids dolichantoside and palicoside. | the enzymatic glucose cleavage of palicoside revealed the biosynthetic pathway to akagerine, whereas the conversion of dolichantoside led to a new quaternary heteroyohimbine alkaloid named n(b)-methyl-21-beta-hydroxy-mayumbine. the hypothetical models of reactions occurring after the conversion of both substrates are proposed. dolichantoside and palicoside, as well as strychnos mellodora stem bark crude ethanol extract, exhibit significant antimycotic activity against human pathogens in presence ... | 2001 | 11397430 |
| enhancement of taxol production and excretion in taxus chinensis cell culture by fungal elicitation and medium renewal. | an endophytic fungus, aspergillus niger, isolated from the inner bark of a taxus chinensis tree, was used as an elicitor to stimulate the taxol (paclitaxel) production in a taxus chinensis cell suspension culture. different elicitor doses and elicitation times were tested in a batch culture; and the highest volumetric taxol yield was achieved when 40 mg of the fungal elicitor (carbohydrate equivalent) l(-1) was added to the culture during the late exponential-growth phase. the elicitation result ... | 2001 | 11398918 |
| selective and sensitive detection of pectin lyase activity using a colorimetric test: application to the screening of microorganisms possessing pectin lyase activity. | several methods have been described for the detection and quantification of polygalacturonase (pg) and pectin lyase (pl) activities. the most frequently used tests are the nelson method using copper(ii) and an arsenomolybdate reagent to detect pg activity, and the colorimetric method using thiobarbituric acid (tba) to detect pl activity. we observed that none of these methods are suitable to differentiate between these two enzymatic activities. therefore, we optimized the test conditions of the ... | 2001 | 11401303 |
| current importance of ochratoxin a-producing aspergillus spp. | ochratoxin a (oa) is receiving attention worldwide because of the hazard it poses to human and animal health. oa contamination of commodities, such as cereals or pork and poultry meat, is well recognized. nevertheless, there is an increasing number of articles reporting oa contamination in other food commodities, such as coffee, beer, wine, grape juice, and milk, in the last few years. this continuous and increasing exposure to oa that humans experience is reflected in the high incidence of oa i ... | 2001 | 11403149 |
| characterization of two genes encoding the mitochondrial alternative oxidase in chlamydomonas reinhardtii. | two cdna clones (aox1 and aox2) and the corresponding genes encoding the alternative oxidases (aoxs) from chlamydomonas reinhardtii were isolated and sequenced. the cdnas, aox1 and aox2, contained open reading frames (orfs) encoding putative proteins of 360 amino acids and 347 amino acids, respectively. for each of the orfs, a potential mitochondrial-targeting sequence was found in the 5'-end regions. in comparison to aox enzymes from plants and fungi, the predicted amino acid sequences of the o ... | 2001 | 11405094 |
| role of pencycuron in aflatoxin production and cotton seed protection. | the research is conducted on the effect of pencycuron and pencycuron-c on cotton seed mycoflora, aflatoxin production and viability. at 8% seed moisture content (mc), pencycuron and pencycuron-c promoted aspergillus niger, a. flavus, and penicillium corylophilum growth count at 1 g/kg, but exerted inhibitory effect at 3 and 5 g/kg. at 15% mc, pencycuron enhanced seed-borne fungi at all three doses after most treatment periods (1, 2, 3, 4, and 5 months), whereas pencycuron-c induced inhibition ef ... | 2001 | 11405276 |
| deterioration and spoilage of peanuts and desiccated coconuts from two sub-saharan tropical east african countries due to the associated mycobiota and their degradative enzymes. | a broad variety of fungi (84 species belonging to 36 genera) were identified with more taxa infesting peanut seed samples from two tropical countries (29 genera and 61 species) compared to those found in desiccated coconuts (20 genera and 55 species) on both drbc and dg18 media. this may be due to the higher moisture levels in peanuts (5.07-7.97%) compared with coconuts (1.5-4.17%). more taxa and propagules were recovered on dg18 in both cases. the dominant fungi from both substrates on both iso ... | 2001 | 11407493 |
| influence of metham sodium on suppression of collar rot disease of peanut, in vitro antibiosis, siderophore production and root colonization by a fluorescent pseudomonad strain fpo4. | a hydroxamate type siderophore producing fluorescent pseudomonas strain, isolated from the rhizoplane of paddy root showing plant growth promoting activity, exhibited a decreased in vitro antibiosis, production of siderophore and suppression of collar rot in presence of metham sodium. use of herbicide had a detrimental effect on the plant growth promoting activity of this organism. the multiple drug resistant mutant strain derived from this rhizobacteria colonized the roots, but the herbicide ap ... | 2000 | 11411048 |
| phenotypic and genotypic characterization of reference strains of the genus aspergillus. | twenty-five culture collection strains from four aspergillus species (a. fumigatus n = 8, a. flavus n = 8, a. niger n = 4, a. nidulans n = 5) were characterized by four methods: (i) determination of patterns in an assimilation assay; (ii) protein pattern of whole mycelial cell lysates in the sodium dodecyl sulphate (sds)-polyacrylamide gel electrophoresis (page); (iii) reactivity of a pool serum obtained from cystic fibrosis patients with mycelial lysates in the immunoblot; and (iv) random ampli ... | 2001 | 11413925 |
| copper removal from aqueous solution using aspergillus niger mycelia in free and polyurethane-bound form. | this study assesses the ability of mycelia of aspergillus niger b-77 (both free and immobilized on polyurethane foam) to remove copper from single-ion solution. all experiments were conducted using 0.5 mm solutions of cuso4.5h2o. mycelia immobilized on polyurethane foam cells showed a three-fold increase in uptake, compared with that of free cells. the efficiency of copper removal (mg cu2+ removed/mg cu2+ added) in a column system reached more than 99% before the break-through point was attained ... | 2001 | 11414333 |
| molecular diagnosis of microbial contamination in cosmetic and pharmaceutical products: a review. | molecular methodologies such as adenosine triphosphate (atp) bioluminescence and polymerase chain reaction (pcr)-based assays provide rapid quality control analysis of cosmetic and pharmaceutical finished products and raw materials. using a single enrichment broth for bacteria, yeast, and mold, atp bioluminescence detected microbial contamination within 27 h. samples were automatically lysed to release microbial atp and light production was quantitated using the celsis optocomp. however, to main ... | 2001 | 11417629 |
| ecg of the month. cardiac tamponade secondary to a. niger-induced constrictive pericarditis. | | 2001 | 11417731 |
| predicting vegetative inoculum performance to maximize phytase production in solid-state fermentation using response surface methodology. | microbial phytase is used to reduce the environmental loading of phosphorus from animal production facilities. the limiting factors in the use of this enzyme in animal feeds can be overcome by solid-state fermentation (ssf), which is a promising technology for commercial enzyme production with lower production costs. inoculum quality and the influence of inoculum quality on phytase production are important factors which need in-depth investigation before scaling-up of high-yielding fermentation ... | 2001 | 11420657 |
| purification and characterization of a beta-glucuronidase from aspergillus niger. | a beta-glucuronidase from pectinex ultra sp-l, a commercial pectolytic enzyme preparation from aspergillus niger, was purified 170-fold by ion-exchange chromatography and gel filtration. apparent m(r) of the purified enzyme, estimated by denaturing gel electrophoresis and size-exclusion chromatography, were 68,000 and 71,000, respectively, indicating that the enzyme is a monomeric protein. it released uronic acids not only from p-nitrophenyl beta-glucosiduronic acid (pnp-glca) but also from acid ... | 2001 | 11423108 |
| identification, classification and phylogeny of the aspergillus section nigri inferred from mitochondrial cytochrome b gene. | the partial mitochondrial cytochrome b gene from 32 strains of 12 species belonging to aspergillus section nigri was amplified by the polymerase chain reaction and sequenced directly. using 402 nucleotide characters, nucleotide-based and amino acid-based phylogenetic trees were inferred and the genetic divergence among the species was evaluated. based on analyses of the 402-bp nucleotide and 133-amino acid sequences, strains were divided into 11 dna types and five amino acid types. aspergillus n ... | 2001 | 11425482 |
| genetic analysis in the asexual fungus aspergillus niger. | the genetics of a. niger has been developed since 1980. an overview is presented of the advances in developing methods and collecting data. important tools have been a) the application of essentially different methods to isolate mutants, b) the adaptation to a. niger ofa. nidulans methodology for analysis of the parasexual cycle, c) the choice of marker genes, and in some cases the artificial introduction of such genes, to select homozygous segregants arising from mitotic recombination. with the ... | 2001 | 11426868 |
| evidence for a non-phosphorylated route of galactose breakdown in cell-free extracts of aspergillus niger. | aspergillus niger could utilize d-galactose as sole source of carbon. cell-free extracts of d-galactose-grown mycelia were able to catalyze the oxidation of d-galactose to d-galactonic acid-gamma-lactone (gala-gamma-lact) in the presence of nad, followed by the appearance of 2-keto-3-deoxy-d-galactonate (kdgal), pyruvate and glyceraldehyde. from 10 &mgr;moles only 6.6 &mgr;moles of gala-gamma-lact were disappeared after 60 min of reaction indicating the presence of gala-gamma-lactonase. identifi ... | 2001 | 11427238 |
| assessment of effects of experimental imprecision on optimized biochemical systems. | metabolic pathways may be optimized with s-system models that prescribe profiles of control variables leading to optimal output while keeping metabolites and enzyme activities within predefined ranges. monte carlo simulations show how much the yield and the corresponding metabolite concentrations would be affected by inaccuracies in the experimental implementation of the prescribed profiles. for a recent model of citric acid production in aspergillus niger, the yield is roughly normally distribu ... | 2001 | 11427946 |
| evaluation of the microbicidal efficacy of steris system i for digestive endoscopes using germande and astm validation protocols. | in the light of more and more invasive procedures being carried out in digestive endoscopy using sterile devices, it appears necessary to put in place a process of endoscope reprocessing capable of ensuring the complete elimination of micro-organisms contaminating the device. we undertook a study of the microbial efficacy of steris system 1 (ss1) which purports to achieve this objective. the channels of a gastroscope and a colonoscope were contaminated with suspensions of pseudomonas aeruginosa, ... | 2001 | 11428881 |
| microbiological transformations. 47. a step toward a green chemistry preparation of enantiopure (s)-2-, -3-, and -4-pyridyloxirane via an epoxide hydrolase catalyzed kinetic resolution. | the biocatalyzed hydrolytic kinetic resolution of 2-, 3-, and 4-pyridyloxirane by the aspergillus niger epoxide hydrolase (eh) has been explored. this was used to perform a gram scale preparation of these epoxides of (s) absolute configuration using a process performed at a concentration as high as 10 g/l (82 mm). all three epoxides have been obtained in a nearly enantiopure form (ee > 98%). interestingly, it was shown that this biotransformation could be achieved using plain water instead of bu ... | 2001 | 11429826 |
| survival of microorganisms under the extreme conditions of the atacama desert. | spores of bacillus subtilis, conidia of aspergillus niger, versicolor and ochraceus and cells of deinococcus radiodurans have been exposed in the dark at two locations (at about 23 degrees s and 24 degrees s) in the atacama desert for up to 15 months. b. subtilis spores (survival approximately 15%) and a. niger conidia (survival approximately 30%) outlived the other species. the survival of the conidia and spores species was only slightly poorer than that of the corresponding laboratory controls ... | 2001 | 11434107 |
| [dependence of the activity of l-amino acid oxidase in the fungus aspergillus niger r-3 on the source of nitrogen in growth media]. | various populations of peroxisomes in cells of aspergillus niger r-3 were formed under the growth in media containing 0.5% glucose and various sources of nitrogen (1/4 of optimal concentrations of (nh4)2so4, l-alanine, and l-methionine). different levels of of l-amino acid oxidase activity were found in these populations of peroxisomes. | 2001 | 11443898 |
| beta-galactofuranoside glycoconjugates on conidia and conidiophores of aspergillus niger. | galactose in the furanoic conformation appears to be limited to bacteria and lower eukaryotes. galactofuranoic (galf)-containing glycoconjugates that occur in organisms pathogenic or allergenic to man are frequently antigenic and immunodominant. we have used an immunochemical approach, employing a monoclonal antibody that recognises galf epitopes, to investigate the presence of galf-containing glycoconjugates within conidia and conidiophores of aspergillus niger. elisa and immunofluorescence mic ... | 2001 | 11445162 |
| changing a single amino acid residue switches processive and non-processive behavior of aspergillus niger endopolygalacturonase i and ii. | processivity, also known as multiple attack on a single chain, is a feature commonly encountered only in enzymes in which the substrate binds in a tunnel. however, of the seven aspergillus niger endopolygalacturonases, which have an open substrate binding cleft, four enzymes show processive behavior, whereas the other endopolygalacturonases are randomly acting enzymes. in a previous study (benen, j.a.e., kester, h.c.m., and visser, j. (1999) eur. j. biochem. 259, 577-585) we proposed that the hi ... | 2001 | 11445590 |
| antimicrobial activity of fabaceae species used in yucatan traditional medicine. | the methanol and water extracts of six fabaceae species, traditionally used in mayan medicine for the treatment of diarrhoea and eye infections, were phytochemically screened and tested for in vitro antimicrobial activity. four species showed activity against gram positive bacteria, five exhibited some activity against candida albicans, two exhibited activity against aspergillus niger and only one, mimosa pigra, inhibited growth of pseudomonas aeruginosa. none of the extracts was active against ... | 2000 | 11449511 |
| identification and characterization of a gene encoding a subtilisin-like serine protease induced during the vegetative incompatibility reaction in podospora anserina. | in the filamentous fungi, cell fusion between unlike individuals generally triggers a cell-death reaction known as vegetative incompatibility. in podospora anserina, it was shown that, during this cell-death reaction, there is a strong increase in proteolytic activity. here, we report the purification of a 36-kda protease that is induced during the incompatibility reaction. an internal peptide of this protein displayed a strong similarity with the pepc subtilisin-like serine protease from asperg ... | 2001 | 11453254 |
| antimicrobial activity of essential oils from plants against selected pathogenic and saprophytic microorganisms. | the beneficial health effects of extracts from many types of plants that are used as seasoning agents in foods and beverages have been claimed for centuries. the purpose of this study was to examine the effectiveness of selected herb and spice essential oils for control of growth and survival of microorganisms. inhibition of growth was tested by the paper disc agar diffusion method. antibiotic susceptibility discs were used as control. minimum lethal concentration (mlc) was determined by the tub ... | 2001 | 11456186 |
| study of fungicidal and antibacterial effect of the cu(ii)-complexes of thiophene oligomers synthesized in zsm-5 zeolite channels. | the influence of the cu(ii)-complexes of thiophene oligomers synthesized by oxidative polymerization of thiophene with cu2+ ions in zsm-5 zeolite channels on fungicidal and antimicrobial properties was studied. it has been found that the heterogeneous system culture medium-modified zeolite increases sporulation of the tested fungus (aspergillus niger) and concurrently kills yeast (candida albicans). these effects are attributed to a slow release of cu2+ ions and thiophene oligomers into the cult ... | 2001 | 11459134 |
| characterization of a novel allele of glucose oxidase from a korean wild type strain of aspergillus niger. | we have identified a novel allele of the glucose oxidase (go, ec1.1.3.4) gene (go) from a korean wild type strain of aspergillus niger, acmo4, with an increased go activity in culture filtrate. southern blot analyses of go from acmo4 (go-acmo4) revealed that the gene was present as a single copy in the genome of a. niger. however, its sequence differs from that of go from a. niger atcc 9029 (go-atcc9029). go-acmo4 appears to be a functional gene based on the fact that it is enzymatically active ... | 2001 | 11459216 |
| optimization of citric acid production from candida lipolytica y-1095 using n-paraffin. | currently, the majority of worldwide microbial production of citric acid utilizes aspergillus niger in a carbohydrate based submerged fermentation. due to their high carbon content, hydrocarbons also have the potential of producing high concentrations of citric acid. initial lab experiments conducted using 1875 ml batch fermentations with n-paraffin found that candida lipolytica nrrl-y-1095 assimilated the feedstock and had a citric acid productivity of 47 mg l(-1) h(-1). to determine the optimu ... | 2001 | 11472797 |
| purification and characterization of a dimethoate-degrading enzyme of aspergillus niger zhy256, isolated from sewage. | a dimethoate-degrading enzyme from aspergillus niger zhy256 was purified to homogeneity with a specific activity of 227.6 u/mg of protein. the molecular mass of the purified enzyme was estimated to be 66 kda by gel filtration and 67 kda by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. the isoelectric point was found to be 5.4, and the enzyme activity was optimal at 50 degrees c and ph 7.0. the activity was inhibited by most of the metal ions and reagents, while it was induced by cu( ... | 2001 | 11472959 |
| real-time monitoring of enzymatic hydrolysis of galactomannans. | enzymatic hydrolysis was monitored in real-time using time dependent static light scattering (tdsls) for a variety of galactomannans from native brazilian flora. alpha-galactosidase, which strips only the (1-6)alpha-d galactose side groups, and beta-mannanase, which hydrolyses only the (1-4)beta-d mannan main chain into oligosaccharides were investigated separately and in combination. the time-dependent signatures matched those describing side-chain stripping for galactosidase, whereas those res ... | 2001 | 11473348 |
| stability and function of interdomain linker variants of glucoamylase 1 from aspergillus niger. | several variants of glucoamylase 1 (ga1) from aspergillus niger were created in which the highly o-glycosylated peptide (aa 468--508) connecting the (alpha/alpha)(6)-barrel catalytic domain and the starch binding domain was substituted at the gene level by equivalent segments of glucoamylases from hormoconis resinae, humicola grisea, and rhizopus oryzae encoding 5, 19, and 36 amino acid residues. variants were constructed in which the h. resinae linker was elongated by proline-rich sequences as ... | 2001 | 11478902 |
| the effect of ph on glucoamylase production, glycosylation and chemostat evolution of aspergillus niger. | the effect of ambient ph on production and glycosylation of glucoamylase (gam) and on the generation of a morphological mutant produced by aspergillus niger strain b1 (a transformant containing an additional 20 copies of the homologous gam glaa gene) was studied. we have shown that a change in the ph from 4 to 5.4 during continuous cultivation of the a. niger b1 strain instigates or accelerates the spontaneous generation of a morphological mutant (lb). this mutant strain produced approx. 50% les ... | 2001 | 11479027 |
| [a case of mucoid impaction of bronchi (mib) due to schizophyllum commune]. | a 51-year-old woman was admitted because of a productive cough. atelectasis of the left upper lobe and eosinophilia were noted. the atelectasis was resolved after bronchoscopic removal of the mucous plug. pathologically, it consisted of eosinophil accumulation with hyphae. cultures of sputum samples revealed schizophyllum commune. we diagnosed this case as mucoid impaction of bronchi due to s. commune. eight months later, a productive cough developed again. chest radiography showed atelectasis o ... | 2001 | 11481826 |
| free polymeric bioligands in aqueous two-phase affinity extractions of microbial xylanases and pullulanase. | two reversibly soluble-insoluble polymers (viz. eudragit s-100 and alginate) were used as free macroaffinity bioligands in polyethylene glycol (peg)/salt two-phase systems for separation of enzymes. incorporation of eudragit s-100 and alginate in the peg phase led to considerable selectivity in separation of microbial xylanases and pullulanase, respectively. xylanase from aspergillus niger was recovered 93% with 56-fold purification, whereas the enzyme from trichoderma reesei and bacillus amylol ... | 2001 | 11483013 |
| preparation of stable, highly active and immobilized glucose oxidase using the anti-enzyme antibodies and f(ab)'2. | immobilization of the aspergillus niger glucose oxidase in high yield was achieved using an immunoaffinity-based procedure. for this purpose iggs, isolated from the sera of rabbits immunized with glucose oxidase, were favourably oriented by binding on to cobalt-charged iminodiacetate-sepharose. large amounts of glucose oxidase could be immobilized by incubating the igg-bound matrix alternately with the enzyme and either intact igg or f(ab)2 derived thereof, leading to the formation of multiple e ... | 2001 | 11483149 |
| galactofuranoic-oligomannose n-linked glycans of alpha-galactosidase a from aspergillus niger. | extracellular alpha-galactosidase a was purified from the culture filtrate of an over-producing strain of aspergillus niger containing multiple copies of the encoding agla gene under the control of the glucoamylase (glaa) promoter. endoglycosidase digestion followed by sds/page, lectin and immunoblotting suggested that glycosylation accounted for approximately 25% of the molecular size of the purified protein. monosaccharide analysis showed that this was composed of n-acetyl glucosamine, mannose ... | 2001 | 11488905 |
| identification and characterization of a family of secretion-related small gtpase-encoding genes from the filamentous fungus aspergillus niger: a putative sec4 homologue is not essential for growth. | dna fragments containing genetic information for five secretion-related small gtpases of aspergillus niger (srga-e) were isolated and identified as members of different rab/ypt subfamilies. this isolation and the search for similar sequences in fungal genomic and est databases showed that, in contrast to saccharomyces cerevisiae, filamentous fungi also possess homologues of mammalian rab2 gtpases. multiple transcripts with unusually long 5' and 3' untranslated regions were found for all srg gene ... | 2001 | 11489135 |
| aspergillus spinal epidural abscess. | spinal abscess due to aspergillus is rare. a young boy with chronic granulomatous disease and aspergillosis of the rib had been treated with antifungal treatment 3 months earlier. the patient presented with a brief history of progressive paraparesis. imaging showed d9--11 vertebral involvement and destruction of the d10 vertebral body with angulation and a large dorsally placed, multiloculated epidural abscess extending from d6 to l2. there was also extensive granulation anterior to and on eithe ... | 2001 | 11490186 |
| enzymatic activity of micro-organisms isolated from cork wine stoppers. | the production of enzymes by micro-organisms which are found on vegetal substrates is important due to their ability to decompose cellulose, lignin and other components, which guarantee the integrity of the vegetal cell. the objective of this study was to determine the enzymatic activity of filamentous fungi, yeasts and bacteria, isolated from natural cork stoppers for bottles of still and sparkling wines. suspensions of fungal conidia, yeasts and bacterial cells of micro-organisms were establis ... | 2001 | 11491526 |
| exopectinases produced by aspergillus niger in solid-state and submerged fermentation: a comparative study. | exopectinase production by aspergillus niger was compared in submerged fermentation (smf) and solid-state fermentation (ssf). ssf was carried out using polyurethane foam (puf) as the solid support. the purpose was to study the effect of sucrose addition (0 or 40 g/l) and water activity level (a(w)=0.99 or 0.96) on the level of enzyme activity induced by 15 g/l of pectin. mycelial growth, as well as extracellular protease production, was also monitored. sucrose addition in smf resulted in catabol ... | 2001 | 11494101 |
| production of tannase by aspergillus niger aa-20 in submerged and solid-state fermentation: influence of glucose and tannic acid. | tannase production by aspergillus niger aa-20 was studied in submerged (smf) and solid-state (ssf) fermentation systems with different tannic acid and glucose concentrations. tannase activity and productivity were at least 2.5 times higher in ssf than in smf. addition of high tannic acid concentrations increased total tannase activity in ssf, while in smf it was decreased. in smf, total tannase activity increased from 0.57 to 1.03 iu/ml, when the initial glucose concentration increased from 6.25 ... | 2001 | 11494106 |
| lysine aminopeptidase of aspergillus niger. | conserved regions within the m1 family of metallo-aminopeptidases have been used to clone a zinc aminopeptidase from the industrially used fungus aspergillus niger. the derived amino acid sequence of apsa is highly similar to two yeast zinc aminopeptidases, lapi and aapi (53.3 and 50.9% overall similarity, respectively), two members of the m1 family of metallo-aminopeptidases. the encoding gene was successfully overexpressed in a. niger and the overexpressed product was purified and characterize ... | 2001 | 11495983 |
| case records of the massachusetts general hospital. weekly clinicopathological exercises. case 24-2001. a 46-year-old woman with chronic sinsusitis, pulmonary nodules, and hemoptysis. | | 2001 | 11496856 |
| a novel pi index and its applications to qspr/qsar studies. | a novel topological index, pi (padmakar-ivan index), is derived in this paper. the index is very simple to calculate and has disseminating power similar to that of the wiener (w) and the szeged (sz) indices. the comprehensive studies show that the proposed pi index correlates highly with w and sz as well as with physicochemical properties and biological activities of a large number of diversified and complex compounds. the proposed pi index promises to be a useful parameter in the qspr/qsar stud ... | 2001 | 11500110 |
| fungal flora of the digestive tract of 5 species of triatomines vectors of trypanosoma cruzi, chagas 1909. | a study of the mycobiota in the digestive tract of 5 important species of triatomines, triatoma brasiliensis, t infestans, t. sordida, t. pseudomaculata and t. vitticeps, was made. the digestive tracts of 164 adults and 535 nymphs of those triatomines were studied and 393 fungal strains were isolated. the genera with the greatest number of species were penicillium (19 species), aspergillus (17 species) and acremonium (5 species) and the most frequent species, in decreasing order, were penicilliu ... | 2001 | 11502063 |
| production of tissue plasminogen activator (t-pa) in aspergillus niger. | a protease-deficient strain of aspergillus niger has been used as a host for the production of human tissue plasminogen activator (t-pa). in defined medium, up to 0.07 mg t-pa (g biomass)(-1) was produced in batch and fed-batch cultures and production was increased two- to threefold in two-phase batch cultures in which additional glucose was provided as a single pulse at the end of the first batch growth phase. production was increased [up to 1.9 mg t-pa (g biomass)(-1)] by the addition of soy p ... | 2001 | 11505386 |
| occurrence of ochratoxin a-producing fungi in raw brazilian coffee. | ochratoxin a (oa)-producing fungi were identified in coffee at different stages of maturation. the toxin was quantified in coffee during terrace drying and in coffee stored in barns. by direct plating, a high level of contamination (100%) was found in the coffee beans studied, with the genus aspergillus representing 33.2%, of which aspergillus ochraceus and aspergillus niger represented 10.3 and 22.9%, respectively, of the strains isolated from the coffee beans. the capacity to produce ochratoxi ... | 2001 | 11510665 |
| [renal abscess in patients with hiv infection in the era of highly active antiretroviral therapy]. | renal abscess is a very rare complication of hiv infection, usually occurs in patients with severe immune deficiency. the immune status is the main factor that predict disease advancement. highly activate antiretroviral therapy (haart) improve the cd4 cell count. we present a case of renal abscess for aspergillus niger in a hiv+ patient who complained of right flank mass and fever. we review relevant literature and the management of these patients. | 2001 | 11512268 |
| factors affecting d-galactonate degradation by extracts of aspergillus niger. | biochemical studies on the degradation of d-galactonate by cell-free extracts of aspergillus niger indicated that the ph value and temperature optima were 8.0 and 7.5 and 40 degrees c and 50 degrees c for the two enzymes responsible for this degradation namely d-galactonate dehydratase and 2-keto-3-deoxy-d-galactonate (kdgal) aldolase respectively. the effects of the nature of the buffer substance, buffer molarity and enzyme concentration were also studied. thermal stability behaviour studies sh ... | 2001 | 11512447 |
| c-terminal propeptide of the caldariomyces fumago chloroperoxidase: an intramolecular chaperone? | the caldariomyces fumago chloroperoxidase (cpo) is synthesised as a 372-aa precursor which undergoes two proteolytic processing events: removal of a 21-aa n-terminal signal peptide and of a 52-aa c-terminal propeptide. the aspergillus niger expression system developed for cpo was used to get insight into the function of this c-terminal propeptide. a. niger transformants expressing a cpo protein from which the c-terminal propeptide was deleted failed in producing any extracellular cpo activity, a ... | 2001 | 11513866 |
| [occupational allergic asthma in greenhouses. report of a clinical case]. | the authors report a particular case of occupational asthma observed in a greenhouse worker. they describe the diagnostic procedure followed after identification on the cultivated plants of colonies of aspergillus niger, a fungus identified as an etiologic agent of the allergic disease. the peculiarity of the causative agent is stressed and it is recommended that environmental and health prevention measures be improved for this poorly protected class of workers. | 2001 | 11515153 |
| [overexpression of artificial synthetic gene of aspergillus niger nrrl3135 phytase in pichia pastoris]. | the phytase gene of aspergillus niger nrrl3135 was modified with a deletion of intron and signal coding sequence. then, according to the codon preference of pichia pastoris, modified phya gene was artificially synthesized and cloned into expression vector of ppicz alpha a. the recombinant plasmid was transformed into chromosome of pichia pastoris x-33 strain by electroporation. the results of sds-page and enzymatic kinetic analysis proved that the recombinant phytase was secreted into culture me ... | 2001 | 11517595 |
| the x-ray structure of aspergillus aculeatus polygalacturonase and a modeled structure of the polygalacturonase-octagalacturonate complex. | polygalacturonases hydrolyze the alpha-(1-4) glycosidic bonds of de-esterified pectate in the smooth region of the plant cell wall. crystal structures of polygalacturonase from aspergillus aculeatus were determined at ph 4.5 and 8.5 both to 2.0 a resolution. a. aculeatus polygalacturonase is a glycoprotein with one n and ten o-glycosylation sites and folds into a right-handed parallel beta-helix. the structures of the three independent molecules are essentially the same, showing no dependency on ... | 2001 | 11518536 |
| the epidemiology of invasive pulmonary aspergillosis at a large teaching hospital. | to characterize the epidemiology of invasive pulmonary aspergillosis (ipa). | 2001 | 11519915 |
| a case study of preservation of semi-solid preparations using the european pharmacopoeia test: comparative efficacy of antimicrobial agents in zinc gelatin. | the present study was undertaken with the aim of finding an alternative preservative system to methyl parahydroxybenzoate in zinc gelatin, which was described in the monographs of the swiss pharmacopoeia (until ph. helv. 8) and in previous editions of the german pharmacopoeia (until dab 7). this antimicrobial agent has now been withdrawn in the dab, because of its potential allergy risks. as for the usp and dab-ddr zinc gelatin preparations, they have always been devoid of any preservative agent ... | 2001 | 11522494 |
| induction of jlba mrna synthesis for a putative bzip protein of aspergillus nidulans by amino acid starvation. | the jlba (jun-like hzip) gene of aspergillus nidulans was isolated. the deduced amino acid motif of the c-terminal region of jlha encodes a putative dna-binding site composed of a basic amino acid domain and an adjacent leucine zipper motif. this region shares highest similarities to the c-terminal dna-binding domain and the basic zipper (bzip)-motifs of transcription factors like cpca from a. niger, gcn4p from saccharomyces cerevisiae, human junb and c-jun. the putative jlba protein contains a ... | 2001 | 11525406 |
| use of the chemiluminescent probe lucigenin to monitor the production of the superoxide anion radical in a recombinant aspergillus niger (b1-d). | direct detection of intracellular superoxide anion radical (o(2)(.-)) production is of critical importance for investigating the responses of filamentous fungi to oxidative stress in bioprocesses. the purpose of this study is to establish a reliable method to monitor the o(2)(.-) production within pellets of aspergillus niger. addition of pure oxygen and the redox cycling agent paraquat to fungal pellet suspensions resulted in a considerable increase in lucigenin-derived chemiluminescence (ldcl) ... | 2001 | 11536143 |
| survival rates of some terrestrial microorganisms under simulated space conditions. | in connection with planetary quarantine, we have been studying the survival rates of nine species of terrestrial microorganisms (viruses, bacteria, yeasts, fungi, etc.) under simulated interstellar conditions. if common terrestrial microorganisms cannot survive in space even for short periods, we can greatly reduce expenditure for sterilizing space probes. the interstellar environment in the solar system has been simulated by low temperature, high vacuum (77 k, 4 x 10(-6) torr), and protons irra ... | 1992 | 11538148 |
| fundamental studies concerning planetary quarantine in space. | if there is a possibility that the organisms carried from earth to space can live for a significant period on planets, the contamination of planets should be prevented for the purpose of future life-detection experiments. in connection with quarantine for interplanetary missions, we have examined the survivabilities of terrestrial microorganisms under simulated space conditions. in this study, examined the survivabilities of terrestrial organisms under simulated mars conditions. the mars cond ... | 1996 | 11538982 |
| studies in the search for life on mars. | the ability of living organisms to survive extraterrestrial conditions has implications for the origins of life in the solar system. we have therefore studied the survival of viruses, bacteria, yeast, and fungi under simulated martian conditions. the environment on mars was simulated by low temperature, proton irradiation, ultraviolet irradiation, and simulated martian atmosphere (co2 95.46%, n2 2.7%, water vapor 0.03%) in a special cryostat. after exposure to these conditions, tobacco mosaic ... | 1995 | 11539227 |
| [warning! a crucial period of searching for life on mars--why international criterion for space quarantine is now required]. | in connection with quarantine for interplanetary mission, we have examined the survivalities of terrestrial microorganisms under simulated mars condition. in this study, the mars conditions were simulated by ultraviolet and proton irradiation under similar low temperature, high vacuum and gaseous conditions by using cryostat vehicle. after exposure to the simulated mars conditions, the survivabilities of the organisms were examined. from the results, the spores of bacillus subtilis, the spores o ... | 1996 | 11540349 |
| planetary quarantine in the solar system. survival rates of some terrestrial organisms under simulated space conditions by proton irradiation. | we have been studying the survival rates of some species of terrestrial unicellular and multicellular organism (viruses, bacteria, yeasts, fungi, algae, etc.) under simulated interstellar conditions, in connection with planetary quarantine. the interstellar environment in the solar system has been simulated by low temperature, high vacuum (77 k, 4 x 10(-8) torr), and proton irradiation from a van de graaff generator. after exposure to a barrage of protons corresponding to about 250 years of irra ... | 1993 | 11541644 |
| chitin-supplemented formulations improve biocontrol and plant growth promoting efficiency of bacillus subtilis af 1. | formulations of a chitinolytic biocontrol and a plant growth promoting bacillus subtilis af 1 were prepared in peat, in peat supplemented with either 0.5% chitin or aspergillus niger mycelium, or in spent compost obtained from agaricus bisporus cultivation and were evaluated for biocontrol of two fungal pathogens and plant growth promoting activities on pigeon pea and groundnut. a steady increase in cell numbers of introduced b. subtilis af 1 was observed in all the formulations at 30 degrees c. ... | 2001 | 11547881 |
| transcriptional autoregulation and inhibition of mrna translation of amino acid regulator gene cpca of filamentous fungus aspergillus nidulans. | the cpca protein of the filamentous fungus aspergillus nidulans is a member of the c-jun-like transcriptional activator family. it acts as central transcription factor of the cross-pathway regulatory network of amino acid biosynthesis and is functionally exchangeable for the general control transcriptional activator gcn4p of saccharomyces cerevisiae. in contrast to gcn4, expression of cpca is strongly regulated by two equally important mechanisms with additive effects that lead to a fivefold inc ... | 2001 | 11553722 |
| molecular cloning of kpca gene encoding a kex2p-like endoprotease from aspergillus nidulans. | we cloned and sequenced a gene, kpca (kex2p-like proprotein convertase a), from a genomic library of aspergillus nidulans. the kpca gene encodes an 820-residue protein, named kpca, which contains a putative subtilisin-like catalytic domain (residues 136-466) homologous to that of the subtilisin serine protease family. kpca shows 56, 73, and 47% amino acid identities with saccharomyces cerevisiae kex2p, aspergillus niger kexb, and mouse furin within the subtilisin-like catalytic domain, respectiv ... | 2001 | 11561725 |
| total synthesis of asperazine. | | 2001 | 11562240 |
| validation of the sterilization procedure of allogeneic avital bone transplants using peracetic acid-ethanol. | different procedures are available to inactivate bacteria and fungi, including their spores, as well as viruses in human bone transplants. the most efficient methods are considered to be gamma irradiation and thermal inactivation as well as chemical sterilization methods like the peracetic acid-ethanol treatment (pes). following national and international standards or draft standards, the antimicrobial effectiveness of this procedure was evaluated. due to the standardizable size as well as the c ... | 2001 | 11580210 |
| identification of the catalytic nucleophile of the family 31 alpha-glucosidase from aspergillus niger via trapping of a 5-fluoroglycosyl-enzyme intermediate. | the mechanism-based reagent 5-fluoro-alpha-d-glucopyranosyl fluoride (5f alpha glcf) was used to trap a glycosyl-enzyme intermediate and identify the catalytic nucleophile at the active site of aspergillus niger alpha-glucosidase (family 31). incubation of the enzyme with 5f alpha glcf, followed by peptic proteolysis and comparative liquid chromatography/ms mapping allowed the isolation of a labelled peptide. fragmentation analysis of this peptide by tandem ms yielded the sequence wydmse, with t ... | 2001 | 11583585 |
| improvement in enzyme productivities from mold cultivations using the liquid-phase oxygen supply strategy. | cultivations of aspergillus niger cells in which oxygen was provided through the liquid-phase oxygen supply strategy (which involves the need-based decomposition of h2o2 pulses to yield the necessary oxygen) were studied. concentrations of h2o2 in the range of 1 to 5 mm were found to be suitable for use in cultivations. the growth rate constant of 0.17 h(-1) obtained in the h2o2-based cultivation, was comparable to that obtained in the cultivation with aeration; however, the maximum cell concent ... | 2001 | 11587571 |
| isolation of uv-induced mutations in the area nitrogen regulatory gene of aspergillus niger, and construction of a disruption mutant. | the area gene of filamentous fungi encodes a positive-acting transcriptional factor required for the expression of genes involved in the utilisation of nitrogen sources other than ammonium and glutamine. in aspergillus niger we have isolated three uv-induced area mutants and constructed a well-defined disruption allele of the area gene. the area gene was genetically localised on linkage group iii, 3.6 map units (m.u.) from bioa1 and 4.5 m.u. from lysa7. analysis of the expression of the nitrate ... | 2001 | 11589576 |
| purification and characterization of benzoate-para-hydroxylase, a cytochrome p450 (cyp53a1), from aspergillus niger. | benzoate-para-hydroxylase (cyp51a or bph) and nadph:cytochrome p450 reductase from the filamentous fungus aspergillus niger were purified to apparent homogeneity, using an overproducing a. niger strain. this is the first membrane-bound fungal cytochrome p450 to be isolated and characterized. combining bph with nadph:cytochrome p450 oxidoreductase in the presence of the phospholipid dilauryl phosphatidylcholine restored the bph activity, although to only a minor extent. spectral analysis of bph s ... | 2001 | 11594739 |
| detection of fungi in sinus fluid of patients with allergic fungal rhinosinusitis. | we aim to develop a rapid, accurate and sensitive diagnostic assay with which to detect the surface antigens of fungi thought to be involved in allergic fungal rhinosinusitis (afrs), by assessing the usefulness of immunofluorescence microscopy (imf) and enzyme linked immuno-absorbent assays (elisa). the age, sex, clinical symptoms and signs, imaging (ct and/or mri), microbiological subculture data, sinus contents, blood eosinophilia, aspergillosis precipitins, radioallergoabsorbent technology (r ... | 2000 | 11603793 |
| an antifungal cadinanolide from pseudoelephantopus spicatus. | a new sesquiterpene lactone was obtained from the chloroform extract of pseudoelephantopus spicatus. its structure was elucidated by extensive one dimentional (1d) and 2d nmr spectroscopy and mass spectrometry. it was found to exhibit moderate antifungal activity against c albicans and a. niger, and low activity against t. mentagrophytes, s. aureus, e. coli and p. aeruginosa. it was inactive against b. subtilis. | 2001 | 11605672 |
| the aspergillus niger d-xylulose kinase gene is co-expressed with genes encoding arabinan degrading enzymes, and is essential for growth on d-xylose and l-arabinose. | the aspergillus niger d-xylulose kinase encoding gene has been cloned by complementation of a strain deficient in d-xylulose kinase activity. expression of xkia was observed in the presence of l-arabinose, l-arabitol and d-xylose. expression of xkia is not mediated by xlnr, the xylose-dependent positively-acting xylanolytic regulator. although the expression of xkia is subject to carbon catabolite repression, the wide domain regulator crea is not directly involved. the a. niger d-xylulose kinase ... | 2001 | 11606204 |
| microbiological transformations. 33. fungal epoxide hydrolases applied to the synthesis of enantiopure para-substituted styrene oxides. a mechanistic approach. | the biohydrolysis of differently para-substituted styrene oxide derivatives was studied, using whole cells of the fungi aspergillus niger or beauveria sulfurescens. these microorganisms proved to be equipped with epoxide hydrolases which are able to achieve these hydrolyses with high enantioselectivity. this allowed the preparation of the optically active epoxides and of the corresponding vicinal diols which were obtained with good to excellent enantiomeric purity. these two microorganisms prove ... | 1996 | 11667667 |
| enzyme microgels in packed-bed bioreactors with downstream amperometric detection using microfabricated interdigitated microsensor electrode arrays. | in this article, we describe the use of ph- responsive hydrogels as matrices for the immobilization of two enzymes, glucose oxidase (gox) and glutamate oxidase (glutox). spherical hydrogel beads were prepared by inverse suspension polymerization and the enzymes were immobilized by either physical entrapment or covalent immobilization within or on the hydrogel surface. packed-bed bioreactors were prepared containing the bioactive hydrogels and these incorporated into flow injection (fi) systems f ... | 2001 | 11668448 |
| asperazine, a selective cytotoxic alkaloid from a sponge-derived culture of aspergillus niger. | | 1997 | 11671801 |
| synthesis and fungicidal activity of substituted pyrazolo[5,4-b] pyridine/pyrid-6-ones and pyrazolo[5,4-d]thiazines. | 6-amino-1-aryloxyaceto-4-aryl-5-cyano-4,5-dihydro-3-methy-l-1h-pyrazolo [5,4-b] pyridines (3)/pyrid-6-ones (4) and 1-aryloxyaceto-6-amino-4-aryl-3-methyl-4h-pyrazolo[5,4-d]-1,3-thiazines (5), have been prepared by michael addition between a,b-unsaturated ketones (2) and malononitrile/ethyl cyanoacetate and thiourea respectively. the antifungal activity against aspergillus niger, helminthosporium oryzae and pyricularia oryzae have been evaluated and compared with commercial fungicide carbendazim ... | 2001 | 11680084 |
| hydrogen peroxide generation with immobilized glucose oxidase for textile bleaching. | glucose oxidase was covalently immobilized on commercially available alumina and glass supports, with a high level of protein recovery. the operational stability of the alumina carrier was an advantage over the glass support, though the rate of generation of hydrogen peroxide in the case of the latter was higher. the immobilization technique provided repeated application of the enzyme even in low concentration, and the hydrogen peroxide generated in the enzymatic reaction was successively used f ... | 2002 | 11690697 |
| [optimization of culture conditions of aspergillus niger for the synthesis of alpha-n-acetylgalactosaminidase and alpha-galactosidase]. | different factors have been investigated for their effect on the process of biosynthesis of alpha-n-acetylgalactosaminidase and alpha-galactosidase of aspergillus niger under deep-water cultivation. optimal sources and concentrations of carbon (soy flour--25 g/l) and nitrogen (pepton--7.5 g/l) were estimated. it has been established that temperature of 25 degrees c, ph 6.0, growing in 50 ml medium at the swing velocity 220 rev/min. for 6-8 days are optimal cultivation parameters. it has been sho ... | 2001 | 11692674 |
| both binding sites of the starch-binding domain of aspergillus niger glucoamylase are essential for inducing a conformational change in amylose. | the interaction of the two binding sites of the starch-binding domain (sbd) of aspergillus niger glucoamylase 1 (ga-i) with substrate has been investigated by using atomic force microscopy (afm) and uv difference spectroscopy in combination with site-specific mutants of both sbd and ga-i. the sbd possesses two binding sites with distinct affinities towards the soluble linear substrate maltoheptaose; dissociation constants (k(d)) of 17 and 0.95 microm were obtained for w563 k (binding site 2 muta ... | 2001 | 11700070 |
| [cloning and expression of aspergillus niger glucose oxidase gene in methylotrophic yeast]. | the dna fragment encoding a. niger glucose oxidase was amplified by pcr using a. niger genomic dna as template, and was cloned into vector of ppic9 for expression in pichia pastoris. when transformed into methylotrophic yeast pichia pastoris gs115, the constructed plasmid ppicgod1 directed the synthesis and secretion of functionally active god. after induction in mm medium for 4 days, the god activity in the medium reached 30-40 u/ml. sds-page revealed that recombinant yeast god was expressed up ... | 2001 | 11702696 |
| pectin degrading glycoside hydrolases of family 28: sequence-structural features, specificities and evolution. | family 28 belongs to the largest families of glycoside hydrolases. it covers several enzyme specificities of bacterial, fungal, plant and insect origins. this study deals with all available amino acid sequences of family 28 members. first, it focuses on the detailed analysis of 115 sequences of polygalacturonases yielding their evolutionary tree. the large data set allowed modification of some of the existing family 28 sequence characteristics and to draw the sequence features specific for bacte ... | 2001 | 11707607 |
| determination of fe(ii) and fe(iii) in water by flame atomic absorption spectrophotometry after their separation with aspergillus niger immobilized on sepiolite. | | 2001 | 11708128 |
| degradation of mannan i and ii crystals by fungal endo-beta-1,4-mannanases and a beta-1,4-mannosidase studied with transmission electron microscopy. | we have used the endo-beta-1,4-mannanase from trichoderma reesei (tr man5a), the endo-beta-1,4-mannanase from aspergillus niger (an man5a) and the exo-beta-1,4-mannosidase from a. niger (an mnd2a) to follow the enzymatic degradation of mannan i and ii crystals. the degradation process was studied by transmission electron microscopy and also followed by analysis of the released soluble reducing sugars. the mannan crystals were degraded by the endo-beta-1,4-mannanases and to a lesser extent by the ... | 2001 | 11710023 |
| triggered enzymatic degradation of a water-soluble polymer solution using a novel inhibitor. | controlled enzymatic degradation of solutions of guar galactomannan, a naturally occurring polysaccharide, offers a powerful tool to enhance its usage in a variety of applications. in this study, we use viscometry to investigate the use of tris(hydroxymethyl)aminomethane (tris) as a reversible, ph-dependent inhibitor to control the degradation of guar galactomannan by aspergillus niger beta-mannanase. viscosity measurements of ph 9 guar solutions containing 25 mm tris show no reduction in the vi ... | 2000 | 11710199 |
| solid state nmr for determination of degree of acetylation of chitin and chitosan. | the degree of acetylation (da) of various samples has been evaluated by 1h liquid-state nmr and 13c and 15n cp-mas solid-state nmr over the whole range of da. a good agreement has been found for all the experiments. the 13c and 15n cp-mas experiments have permitted the evaluation of the chitin da and content in the structural polysaccharides in a fungus named aspergillus niger. the fungus structural carbohydrates mainly consist in pure chitin associated with glucans. comparison of the 13c cp-mas ... | 2000 | 11710206 |
| enzymatic degradation of guar and substituted guar galactomannans. | enzymatic degradation of guar galactomannan is studied using gel permeation chromatography (gpc) and steady shear viscometry. in very dilute polymer solutions, reaction rate increases with first-order kinetics with substrate concentration. in the intermediate concentration regime, the enzyme/polymer binding saturates, and the degradation kinetics is zero-order. the observations are in accord with a michaelis-menton kinetics model. the michaelis-menton parameter, km and vmax, were determined to b ... | 2000 | 11710212 |
| use of fungal phytase to improve breadmaking performance of whole wheat bread. | the possible use of phytase as a breadmaking improver has been tested in whole wheat breads by adding different amounts of fungal phytase. the effect of phytase addition on the fermentation stage and the final bread quality was analyzed. the phytase addition shortened the fermentation period, without affecting the bread dough ph. regarding the whole wheat bread, a considerable increase of the specific bread volume, an improvement of the crumb texture, and the width/height ratio of the bread slic ... | 2001 | 11714342 |
| a spectrophotometric method to assay epoxide hydrolase activity. | the aspergillus niger epoxide hydrolase activity was assayed by spectrophotometric using (rac) p-nitrostryrene oxide (pnso) as substrate. both the substrate (pnso) and the reaction product, p-nitrostryrene diol (pnsd), had a strong absorbance in uv at 280 nm. the assay was based on the measure of the pnsd absorbance of the water phase after extraction of the non-reacted pnso with a solvent. among the five solvents tested, chloroform was selected since it extracted more than 99% of the epoxide an ... | 2001 | 11714507 |
| construction of a fusion enzyme system by gene splicing as a new molecular recognition element for a sequence biosensor. | a bifunctional fusion enzyme system constructed by gene splicing is proposed as a new model to develop sequence biosensors, taking maltose biosensor as an example. the cdna fragment of aspergillus niger glucoamylase (e.c 3.2.1.3, ga) was fused to the 3' end of aspergillus niger glucose oxidase (e.c 1.1.3.4, god) gene with the insertion of a flexible linker peptide [-(ser-gly)5-] coding sequence. the fusion gene was cloned into the vector ppic9 and expressed in pichia pastoris gs115 under the con ... | 2001 | 11716683 |
| new synthesis and new bio-application of cyclometalated ruthenium(ii) complexes for fast mediated electron transfer with peroxidase and glucose oxidase. | | 2001 | 11720516 |