| comparison of the thermostability properties of three acid phosphatases from molds: aspergillus fumigatus phytase, a. niger phytase, and a. niger ph 2.5 acid phosphatase. | enzymes that are used as animal feed supplements should be able to withstand temperatures of 60 to 90 degrees c, which may be reached during the feed pelleting process. the thermostability properties of three histidine acid phosphatases, aspergillus fumigatus phytase, aspergillus niger phytase, and a. niger optimum ph 2.5 acid phosphatase, were investigated by measuring circular dichroism, fluorescence, and enzymatic activity. the phytases of a. fumigatus and a. niger were both denatured at temp ... | 1998 | 9797305 |
| morphogenetic and biochemical effects of dissolved carbon dioxide on filamentous fungi in submerged cultivation. | the inhibitory effects of elevated co2 in submerged fermentation processes involving bacteria and yeasts have been extensively examined. however, until recently, there have been few similar studies involving filamentous fungi, despite the economic importance of this group of organisms. many of the investigations that have been carried out have involved inappropriate simulation methods and, as a result, may have overestimated the morphogenetic and biochemical effects of elevated co2 on filamentou ... | 1998 | 9802213 |
| an enzyme-linked immunosorbent assay for the estimation of fungal biomass during solid-state fermentation. | an enzyme-linked immunosorbent assay for sensitive, specific and quantitative estimation of fungal biomass during solid-state fermentation is described. using this method, differential growth rates and colonization of the substrate can be studied. the assay has potential application for the efficient monitoring of solid-state fermentation involving specific fungus, for which available methods are not adequate. | 1998 | 9802214 |
| softwood hemicellulose-degrading enzymes from aspergillus niger: purification and properties of a beta-mannanase. | the enzymes needed for galactomannan hydrolysis, i.e., beta-mannanase, alpha-galactosidase and beta-mannosidase, were produced by the filamentous fungus aspergillus niger. the beta-mannanase was purified to electrophoretic homogeneity in three steps using ammonium sulfate precipitation, anion-exchange chromatography and gel filtration. the purified enzyme had an isoelectric point of 3.7 and a molecular mass of 40 kda. ivory nut mannan was degraded mainly to mannobiose and mannotriose when incuba ... | 1998 | 9803534 |
| [the evaluation of antigens and antisera for their use in the serodiagnosis of aspergillosis]. | aspergillosis became an important opportunistic mycosis during the last years, with a great variety of clinical manifestations. to contribute to the replenishing of this mycosis serodiagnosis, biologic reactives (antigens and antisera) were prepared from strains of the species aspergillus niger, aspergillus flavus and aspergillus terreus for their use in immunoprecipitation assays. the reactives were assessed by double immunospreading versus a reference commercial system; satisfactory results we ... | 1995 | 9805081 |
| molecular cloning and sequence analysis of two endoinulinase genes from aspergillus niger. | two genomic dnas encoding endoinulinase from aspergillus niger 12 were cloned and sequenced. open reading frames (orfs) of the endoinulinase genes, inua and inub, both consisted of 1,548 nucleotides encoding 516 amino acids. it was suggested that the coding regions were not interrupted by introns. the orfs differed from each other by 23 nucleotide substitutions or by eight amino acid replacements, indicating that the inua and inub genes arose by gene duplication. each mature enzyme of 493 amino ... | 1998 | 9805373 |
| enzymatic synthesis and characterization of 6-o-beta-d-xylopyranosyl-2-acetamido-2-deoxy-d-glucopyranose, a structural analog of primeverose. | the synthesis of the disaccharide 6-o-beta-d-xylopyranosyl-2-acetamido-2-deoxy-d-glucopyranose (n-acetylprimeverosamine), structurally related to the natural disaccharide 6-o-beta-d-xylopyranosyl-d-glycopyranose (primeverose), was obtained via a transglycosylation reaction catalyzed by a crude preparation of beta-d-xylosidase from aspergillus niger, using p-nitrophenyl beta-d-xylopyranoside as the donor and 2-acetamido-2-deoxy-d-glucopyranose as the acceptor. the yield of the reaction was 36% on ... | 1998 | 9821268 |
| studies on toxigenic fungi in roasted foodstuff (salted seed) and halotolerant activity of emodin-producing aspergillus wentii. | commercial roasted salted peanuts (3% nacl), popcorn (1% nacl), summer-squash (9% nacl), sunflower (3% nacl) and wild-melon (3% nacl) seeds are polluted with fungi, mostly aspergillus flavus, a. niger, penicillium chrysogenum, p. corylophilum and rhizopus stolonifer. contamination of popcorn with the fungi is about 10 times higher than in the other foods. these fungi, common also on unsalted seeds, are significantly inhibited in seeds (30% moisture content) treated with 9-21% nacl. the halotoler ... | 1998 | 9821293 |
| synthesis, antifungal activity and antibacterial evaluation of some 3-piperazinylmethyl-5-aryl-1h-1,2,4-triazoles. | some new 3-piperazinylmethyl-5-aryl-1h-1,2,4-triazoles have been prepared and tested for their antifungal and antimicrobial activity. among them, compounds 3g and 3h exhibited higher antifungal activity than ketoconazole against cladosporium cladosporoides and aspergillus niger respectively. | 1998 | 9825120 |
| characterization of antigenic epitopes in anti-ulcer pectic polysaccharides from bupleurum falcatum l. using several carbohydrases. | a polyclonal antibody (anti-bupleuran 2iic/pg-1-igg) against the "ramified" region (pg-1) of an anti-ulcer pectic polysaccharide was prepared and its antigenic epitopes were analyzed by using several carbohydrases. enzymatic removal of arabinosyl residues from pg-1 by endo-(1-->5)-alpha-l-arabinanase (from aspergillus niger) did not reduce the binding ability of anti-bupleuran 2iic/pg-1-igg to pg-1. when the endo-(1-->5)-alpha-l-arabinanase-resistant fraction (ea-1) was digested with rhamnogalac ... | 1998 | 9825524 |
| [scanning electron microscope sudy of the morphology of fungi isolated from patients at the aristide la dantec hospital in dakar, senegal]. | in order to improve the identification of fungi usually isolated among some patients at dantec hospital, a study by scanning electron microscopy has been carried out. it deals with four species of yeasts (candida albicans, candida parapsilosis, rhodotorula rubra sacharomyces cerevisiae) six species of dermatophytes (trichophyton rubrum, trichophyton soudanense, trichophyton interdigitale, microsporum canis, trichophyton violaceum, microsporum audouinii); two species of mildew, (aspergullus flavu ... | 1996 | 9827085 |
| endocarditis caused by aspergillus niger: case report. | | 1998 | 9827292 |
| colonization of maize grain by fusarium moniliforme and fusarium proliferatum in the presence of competing fungi and their impact on fumonisin production. | this study was carried out to determine the effect of water activity (aw) and temperature on the patterns of colonization of maize grain by isolates of fusarium moniliforme and f. proliferatum in the presence of interacting spoilage fungi, such as aspergillus flavus, a. niger, a. ochraceus, and penicillium implicatum, over 4-week incubation periods. the impact that such interactions have on fusarium infection of maize grain and populations and on the production of fumonisins were all evaluated. ... | 1998 | 9829191 |
| microorganism inactivation using high-pressure generation in sealed vessels under sub-zero temperature. | in order to test the possibility of utilizing high pressure in bioscience and biotechnology, a simple method for high-pressure generation and its use for microbial inactivation have been studied. when a pressure vessel was filled with water, sealed tightly and cooled to sub-zero temperatures, high pressure was generated in the vessel. the pressure generation was 60 mpa at -5 degrees c, 103 mpa at -10 degrees c, and 140 mpa at -15 degrees c, -20 degrees c, and -22 degrees c. the high pressure gen ... | 1998 | 9830091 |
| analysis of the role of the gene bipa, encoding the major endoplasmic reticulum chaperone protein in the secretion of homologous and heterologous proteins in black aspergilli. | the function of the endoplasmic-reticulum-localized chaperone binding protein (bip) in relation to protein secretion in filamentous fungi was studied. it was shown that the overproduction of several homologous and heterologous recombinant proteins by aspergillus strains induces the expression of bipa, the bip-encoding gene from aspergillus niger and aspergillus awamori. as this result could imply that bip plays a role in protein overproduction, the effect of modulation of bipa gene expression on ... | 1998 | 9830095 |
| aspects of the mechanism of catalysis of glucose oxidase: a docking, molecular mechanics and quantum chemical study. | the complex structure of glucose oxidase (gox) with the substrate glucose was determined using a docking algorithm and subsequent molecular dynamics simulations. semiempirical quantum chemical calculations were used to investigate the role of the enzyme and fad co-enzyme in the catalytic oxidation of glucose. on the basis of a small active site model, substrate binding residues were determined and heats of formation were computed for the enzyme substrate complex and different potential products ... | 1998 | 9834905 |
| [ocular perforation in the agrarian environment]. | | 1998 | 9835155 |
| stability of porcine and microbial lipases to conditions that approximate the proventriculus of young birds. | in vitro experiments were conducted to characterize the activity and the stability of lipase from animal (crude porcine, cpl; lyophilized porcine, lpl), fungal (rhizopus arrhizus, ral; aspergillus niger, anl), and bacterial (two pseudomonas spp., pl1, pl2; and chromobacterium viscosum, cvl) sources when exposed to conditions associated with the glandular stomach. activity was measured at ph 3 to 8, 40 c and then monitored in response to temperature (40 c), time of exposure (0 and 30 min), ph (3 ... | 1998 | 9835341 |
| stability of porcine and microbial lipases to conditions that approximate the small intestine of young birds. | in vitro experiments were conducted to study the stability of lipase activities from bacterial, fungal, and animal sources under conditions that approximate the small intestine. in the first experiment, the effects of preincubation with trypsin (500, 1,000, and 2,000 u/ml), chymotrypsin (200, 400, and 800 u/ml), and trypsin plus chymotrypsin (tc; 2,000 u/ml trypsin + 800 u/inl chymotrypsin) for 30 min at 40 c, on lipase activities from sources of pseudomonas spp. (pl1, pl2), chromobacterium visc ... | 1998 | 9835342 |
| role of physical properties of glycidyl methacrylate- pentaerythritol triacrylate copolymers on immobilization of milk clotting protease from aspergillus niger mc4 | the effect of cross-link density and amount of porogen on physical properties of the glycidyl methacrylate-pentaerythritol triacrylate (gma-peta) copolymer and intern on the immobilization of milk clotting protease from aspergillus niger mc4 was studied. almost quantitative expression of the milk clotting protease was achieved with copolymer of 251% cross-link density and generated with 65.4 ml of cyclohexanol as porogen. the ph of 4.0 and 18 h period were the best conditions for binding the mil ... | 1998 | 9841650 |
| continuous production of cheese by immobilized milk-clotting protease from aspergillus niger mc4 | milk clotting protease from aspergillus niger mc4 immobilized on glycidyl methacrylate-pentaerythritol triacrylate copolymer gp4 was used for continuous production of cheese using a packed bed reactor. factors affecting the hydrolysis of kappa-casein and clot formation were studied. acidified milk (ph 5.8) preincubated at 37 degreesc when passed through the column at a flow rate of 80 ml/min attained the required degree of hydrolysis of kappa-casein for the coagulation in a single pass. fortific ... | 1998 | 9841651 |
| o-glycbase version 4.0: a revised database of o-glycosylated proteins. | o-glycbase is a database of glycoproteins with o-linked glycosylation sites. entries with at least one experimentally verified o-glycosylation site have been compiled from protein sequence databases and literature. each entry contains information about the glycan involved, the species, sequence, a literature reference and http-linked cross-references to other databases. version 4.0 contains 179 protein entries, an approximate 15% increase over the last version. sequence logos representing the ac ... | 1999 | 9847232 |
| preliminary antifungal and cytotoxicity studies of extracts of ritchiea capparoides var. longipedicellata. | crude extracts obtained from the leaves, stem bark and roots of ritchiea capparoides var. longipedicellata were screened for in vitro antifungal activity using the agar tube dilution method. the leaf hexane, leaf methanol, stem bark methanol and root methanol extracts were tested using ten clinical strains of fungi at a concentration of 200 and 400 microg/ml, respectively. at 400 microg/ml, all four extracts inhibited the growth of six of the ten test fungi used in the study. inhibition of the g ... | 1998 | 9849635 |
| enumeration and identification of aspergillus group and penicillium species in poultry feeds from argentina. | a total of 180 samples of poultry feeds were collected during 1996 and 1997 from different factories in the south of the province of córdoba-argentina. they were examined for the occurrence of penicillium spp. and aspergillus group species. likewise, the capacity to produce aflatoxins by the aspergillus section flavi group was determined. the predominant species of aspergillus were a. flavus and a. parasiticus. for penicillium spp., p. brevicompactum, p. purpurogenum and p. oxalicum were identif ... | 1998 | 9850595 |
| determinants of the fidelity of processing glucoamylase-lysozyme fusions by aspergillus niger. | fusion proteins are used to enhance the yields of heterologous proteins secreted from filamentous fungi. in aspergillus niger, the target protein is normally fused downstream of the carrier protein glucoamylase with a lys-arg kex2-like cleavage site at the junction. this is cleaved in vivo to release mature protein but the processing is not always accurate. we have used n-terminal mutant lysozymes to vary the sequence immediately downstream of the kex site, and also varied the amino acid sequenc ... | 1998 | 9851698 |
| cloning and biochemical characterisation of aspergillus niger hexokinase--the enzyme is strongly inhibited by physiological concentrations of trehalose 6-phosphate. | the aspergillus niger hexokinase gene hxka has been cloned by heterologous hybridisation using the aspergillus nidulans hexokinase gene as a probe. the dna sequence of the gene was determined, and the deduced amino acid sequence showed significant similarity to other eukaryotic hexokinase and glucokinase proteins, in particular to those of the budding yeasts. the encoded protein was purified from a multicopy hxka transformant, and extensively characterised. the hexokinase protein has a molecular ... | 1998 | 9851713 |
| carob pod: a new substrate for citric acid production by aspergillus niger. | the production of citric acid from carob pod extract by a. niger in surface fermentation was investigated. a maximum citric acid concentration (85.5 g/l), citric acid productivity (4.07 g/l/d), specific citric acid production rate (0.18 g/g/d), and specific sugar uptake rate (0.358 g/g/d) was achieved at an initial sugar concentration of 200 g/l, ph of 6.5, and a temperature of 30 degrees c. other kinetic parameters, namely, citric acid yield, biomass yield, specific biomass production rate, and ... | 1998 | 9854802 |
| study on splitting of sucrose glycoside bonds by beta-fructosidase of aspergillus niger vkm f-801. | functional groups of beta-fructosidase of aspergillus niger vkm f-801 were identified. based on the ph dependence of the enzyme, the calculated heat of ionization, the photoinactivation of the enzyme in the presence of methylene blue photosensitizer, and also the enzyme inactivation by diethyl pyrocarbonate, the catalytic center of the beta-fructosidase was found to include carboxyl and imidazole groups of amino acid residues. the glycoside bond in the sucrose molecule is apparently cleaved by t ... | 1998 | 9864459 |
| an immunoaffinity procedure for determination of enzyme activity at elevated temperatures. | | 1998 | 9866696 |
| the occurrence of fungi along the red sea coast and variability among isolates of fusarium as revealed by isozyme analysis. | nineteen identified species which belong to nine fungal genera were recovered from 14 samples collected from different sites of the red sea governorate. the aquatic fungal genera were allomyces, dictyuchus, saprolegnia and pythium while, the terrestrial fungal genera were aspergillus, penicillium, fusarium, neurospora and rhizopus. aspergillus was the most frequent genus, represented by seven species, of which a. niger, a. flavus and a. ustus were the most common. penicillium was of occurred les ... | 1998 | 9871328 |
| sequence analysis, overexpression, and antisense inhibition of a beta-xylosidase gene, xyla, from aspergillus oryzae kbn616. | beta-xylosidase secreted by the shoyu koji mold, aspergillus oryzae, is the key enzyme responsible for browning of soy sauce. to investigate the role of beta-xylosidase in the brown color formation, a major beta-xylosidase, xyla, and its encoding gene were characterized. beta-xylosidase xyla was purified to homogeneity from culture filtrates of a. oryzae kbn616. the optimum ph and temperature of the enzyme were found to be 4.0 and 60 degrees c, respectively, and the molecular mass was estimated ... | 1999 | 9872754 |
| investigation of the glycosyltransferase enzymes involved in the initial stages of the n-linked protein glycosylation pathway in aspergillus niger. | a protocol has been developed to produce functional microsomes from mycelium of aspergillus niger. using these preparations, radioactive biochemical assays have been designed and optimised to measure the in vitro activities of three of the enzymes of the n-linked dolichol phosphate (dol-p) glycosylation pathway: udp-n-glcnac:dolichol-p glcnac-1-p transferase (gpt), dol-p mannose synthase (dpms) and dol-p glucose synthase (dpgs). exogenous dol-p and triton x-100 are essential for in vitro activit ... | 1999 | 9878696 |
| colonisation and competitiveness of aspergillus and penicillium species on maize grain in the presence of fusarium moniliforme and fusarium proliferatum. | the effects of different steady-state water activity levels (a(w), 0.93, 0.95 and 0.98) and temperature (15 and 25 degrees c) on colonisation patterns of aspergillus and penicillium spp., when colonising irradiated maize grain in the presence of fusarium moniliforme and fusarium proliferatum were assayed in terms of populations (colony forming units, cfus g grain(-1)), seed infection and colonisation rates. the activity of f. moniliforme and f. proliferatum in grain reduced the presence of asper ... | 1998 | 9924941 |
| biophysical characterization of fungal phytases (myo-inositol hexakisphosphate phosphohydrolases): molecular size, glycosylation pattern, and engineering of proteolytic resistance. | phytases (myo-inositol hexakisphosphate phosphohydrolases) are found naturally in plants and microorganisms, particularly fungi. interest in these enzymes has been stimulated by the fact that phytase supplements increase the availability of phosphorus in pig and poultry feed and thereby reduce environmental pollution due to excess phosphate excretion in areas where there is intensive livestock production. the wild-type phytases from six different fungi, aspergillus niger, aspergillus terreus, as ... | 1999 | 9925554 |
| biochemical characterization of fungal phytases (myo-inositol hexakisphosphate phosphohydrolases): catalytic properties. | supplementation with phytase is an effective way to increase the availability of phosphorus in seed-based animal feed. the biochemical characteristics of an ideal phytase for this application are still largely unknown. to extend the biochemical characterization of wild-type phytases, the catalytic properties of a series of fungal phytases, as well as escherichia coli phytase, were determined. the specific activities of the fungal phytases at 37 degreesc ranged from 23 to 196 u. (mg of protein)-1 ... | 1999 | 9925555 |
| production, properties, and application of xylanase from aspergillus niger a3. | | 1998 | 9928094 |
| stability in organic solvent mixtures of beta-glucosidase and beta-fructofuranosidase as dry powder and entrapped in poly-hema. | | 1998 | 9928095 |
| horizontal gene transfer involved in the convergent evolution of the plasmid-encoded enantioselective 6-hydroxynicotine oxidases. | the d- and l-specific nicotine oxidases are flavoproteins involved in the oxidative degradation of nicotine by the gram-positive soil bacterium arthrobacter nicotinovorans. their structural genes are located on a 160-kbp plasmid together with those of other nicotine-degrading enzymes. they are structurally unrelated at the dna as well as at the protein level. each of these oxidases possesses a high degree of substrate specificity; their catalytic stereoselectivity is absolute, although they are ... | 1999 | 9929386 |
| crystallographic and mutational analyses of an extremely acidophilic and acid-stable xylanase: biased distribution of acidic residues and importance of asp37 for catalysis at low ph. | xylanase c from aspergillus kawachii has an optimum ph of 2.0 and is stable at ph 1.0. the crystal structure of xylanase c was determined at 2.0 a resolution (r-factor = 19.4%). the overall structure was similar to those of other family 11 xylanases. asp37 and an acid-base catalyst, glu170, are located at a hydrogen-bonding distance (2.8 a), as in other xylanases with low ph optima. asp37 of xylanase c was replaced with asparagine and other residues by site-directed mutagenesis. analyses of the ... | 1998 | 9930661 |
| cloning and expression of the cdna encoding an alternative oxidase gene from aspergillus niger wu-2223l. | a cdna fragment encoding the mitochondrial alternative oxidase, the enzyme responsible for cyanide-insensitive and salicylhydroxamic acid (sham)-sensitive respiration, from the citric acid-producing fungus aspergillus niger wu-2223l was cloned and expressed in escherichia coli as a host strain. synthetic primers were designed from the conserved nucleotide sequences of the alternative oxidase genes from higher plants and a yeast. the 210-bp dna fragment was amplified by pcr with these primers usi ... | 1999 | 9933359 |
| glaa promoter controlled production of a mutant green fluorescent protein (s65t) by recombinant aspergillus niger during growth on defined medium in batch and fed-batch cultures | the first successful expression of the aequorea victoria green fluorescent protein (gfp) gene in aspergillus niger is described. when the wild-type gfp gene was expressed in a. niger, neither the fluorescence nor the full translation product of the wtgfp gene was detectable. however, the expression of a mutant form of the green fluorescent protein (s65tgfp) gene resulted in the formation of a functional fluorescent polypeptide. the synthesis of s65tgfp was used to study glaa promoter controlled ... | 1999 | 9933512 |
| immobilization of polymethylgalacturonase producing aspergillus niger on luffa sponge material. | the vegetable sponge of luffa cylindrica was studied as a matrix for the immobilization of aspergillus niger 26, producer of polymethylgalacturonase (pmg). entrapped spores could grow and multiply within the lattice of the sponge. the influence of loofa sponge inoculum content, initial spore inoculum content, and duration of the growth cycle on the enzyme activity and mycelium growth was studied. the best yield of pmg was reached with 1 piece of loofa sponge (approx. 0.10 g dry weight), 10(9) sp ... | 1998 | 9933964 |
| utility of wiring nitrate reductase by alkylpyrroleviologen-based redox polymers for electrochemical biosensor and bioreactor applications. | the purpose of this work was to see if the alkylpyrroleviologen redox polymer technology previously developed for a reagentless nitrate biosensor based on nitrate reductase (nar) from escherichia coli (cosnier, s.; innocent, c.; jouanneau, y. anal. chem. 1994, 66, 3198-3201) could be applied to the isozyme from aspergillus niger. in particular, the enzyme viability after immobilization was of great interest, as cosnier et al. reported a residual activity of only 0.33% of the amount initially app ... | 1999 | 9949735 |
| thermal unfolding of the starch binding domain of aspergillus niger glucoamylase. | a fragment of the starch-binding domain (sbdf) of aspergillus niger glucoamylase was prepared using recombinant dna techniques, and its thermal unfolding was investigated by high-sensitivity differential scanning calorimetry (dsc). thermal unfolding of sbdf was found to be reversible at ph 7 as expected from a dsc study of the whole enzyme molecule [tanaka a. et al., j. biochem., 117, 1024-1028 (1995)] but not reversible at acidic region. numerical analysis of the dsc curves showed that the dena ... | 1998 | 9972233 |
| effects of carbohydrate chain on surface net charge and hydrophobicity of glycoenzymes. | three different carbohydrate-depleted enzymes were prepared from an endo-beta-1,4-glucanase of aspergillus niger ifo31125 by treatment with endo-beta-n-acetylglucosaminidase or alpha-mannosidase. the molecular sizes of these enzymes decreased from 40 kda containing about 8.9% carbohydrate to 39, 38, and 37 kda with carbohydrate at 4.5, 1.3, and 0.8% (w/w), respectively. the surface net charges on these enzyme preparations were calculated from their electrophoretic mobilities measured by capillar ... | 1998 | 9972237 |
| recombinant glucoamylase production by aspergillus niger b1 in chemostat and ph auxostat cultures. | the production of glucoamylase (gam) by aspergillus niger b1, a genetic transformant containing an additional 20 copies of the homologous glucoamylase gene (glaa) was studied in nutrient (maltodextrin)-limited chemostat and nutrient-excess ph auxostat cultures. in these culture systems the specific production rate of gam increased with dilution rate and reached a maximum (up to 15.0 mg gam [g biomass]-1 h-1) when a. niger b1 was grown at its maximum specific growth rate in ph auxostat culture, i ... | 1998 | 9974221 |
| molecular diagnosis and epidemiology of fungal infections. | a variety of methods are utilized for dna strain subtyping of candida spp. because no 'gold standard' exists. random amplified polymorphic dna (rapd) or restriction enzyme analysis (rea) are useful to determine the source of an outbreak, but more reproducible and discriminatory methods such as southern hybridization and pulsed field gel electrophoresis (pfge) may be required. when applied to some nosocomial candida infections, multiple strains and species have been identified. microevolution of ... | 1998 | 9988514 |
| effect of chemical nutrients on aconitase activity during citric acid fermentation by a mutant strain of aspergillus niger. | an ethyleneimine and uv irradiated mutant strain aspergillus niger ab 1801 was explored for its aconitase activity, citric acid production and cell growth during citric acid fermentation. 10% sucrose and 0.25% urea served as the best carbon and nitrogen sources, respectively. fe2+ stimulated aconitase activity and co2+ (upto 5 micrograms/ml) and ni2+ (10 micrograms/ml) strongly depressed enzyme activity. boric acid (0.5 mg/l) had very good stimulatory response towards citric acid production. aco ... | 1998 | 9990708 |
| specific, uncompetitive inhibition of beta-galactosidases by a 5,6-isopropylidenedioxyfuro[2,3-d]isoxazole-3-methanol derivative. | (-)-(3as,5s,6s.6ar)-3a,5,6,6a-tetrahydro-5,6-isopropylide nedioxyfuro [2,3-d]isoxazole-3-methanol ((-)-5) has been tested toward 25 glycohydrolases and found to inhibit beta-galactosidase from aspergillus niger (ki = 18 microm) and that from aspergillus orizae (ki = 72 microm). hydrolysis of the acetonide or exchange of ch2oh group for a cho, ch2ome or a ch2omom group suppresses the inhibitory activity. | 1999 | 10021944 |
| baker's asthma due to the enzyme xylanase -- a new occupational allergen. | the asthmatic baker showed ige-mediated sensitization to xylanase of aspergillus niger used as a baking additive. inhalative challenge with approximately 0.5 microg of the enzyme resulted in an immediate-type asthmatic reaction. this case, as well as a preliminary screening of symptomatic bakers, shows that xylanase is a further relevant type i-sensitizer in the baking industry. | 1998 | 10024232 |
| a novel class of protein from wheat which inhibits xylanases. | we have purified a novel class of protein that can inhibit the activity of endo-beta-1,4-xylanases. the inhibitor from wheat (triticum aestivum, var. soisson) is a glycosylated, monomeric, basic protein with a pi of 8.7-8.9, a molecular mass of 29 kda and a unique n-terminal sequence of aggktgqvtvfwgrn. we have shown that the protein can inhibit the activity of two family-11 endo-beta-1, 4-xylanases, a recombinant enzyme from aspergillus niger and an enzyme from trichoderma viride. the inhibitor ... | 1999 | 10024521 |
| pectin methylesterase gene (pmea) from aspergillus oryzae kbn616: its sequence analysis and overexpression, and characterization of the gene product. | a gene (pmea) encoding pectin methylesterase was isolated from a shoyu koji mold, aspergillus oryzae kbn616, and characterized. the structural gene comprised 1,370 bp with six introns. the pmea protein consisted of 331 amino acids with a putative signal peptide of 17 amino acids. the deduced amino acid sequence was very similar to those of aspergillus niger pmea and aspergillus aculeatus pme1. the pmea gene was efficiently expressed under control of the a. oryzae tef1 gene promoter for purificat ... | 1999 | 10052131 |
| purification and characterization of methylamine oxidase induced in aspergillus niger aku 3302. | crude extract of aspergillus niger aku 3302 mycelia incubated with methylamine showed a single amine oxidase activity band in a developed polyacrylamide gel that weakly cross-reacted with the antibody against a copper/topa quinone-containing amine oxidase (ao-ii) from the same strain induced by n-butylamine. since the organism cannot grow on methylamine and the already known quinoprotein amine oxidases of the organism cannot catalyze oxidation of methylamine, the organism was forced to produce a ... | 1999 | 10052132 |
| citric acid production from xylan and xylan hydrolysate by semi-solid culture of aspergillus niger. | citric acid production from xylan and xylan hydrolysate was done by aspergillus niger yang no. 2 cultivated in a semi-solid culture using bagasse as a carrier. yang no. 2 produced 72.4 g/l and 52.6 g/l of citric acid in 5 d from 140 g/l of xylose and arabinose, respectively. yang no. 2 produced 51.6 g/l of citric acid in 3 d from a concentrated xylan hydrolysate prepared by cellulase treatment, containing 100 g/l of reducing sugars. moreover, yang no. 2 directly produced 39.6 g/l of citric acid ... | 1999 | 10052148 |
| study of the micro-organisms associated with the fermented bread (khamir) produced from sorghum in gizan region, saudi arabia. | traditional bread (khamir) was made from sorghum flour of two local varieties, bayadh and hamra. the bread was prepared by mixing the sorghum flour with water and spices (onion, garlic, lemon juice and fenugreek) in a 1:0.8 (w/w) ratio and fermented for 24 h at 30 degrees c. two other fermentations were carried out using an inoculum from the previous fermentation. the micro-organisms were isolated from different plates and identified using different characterization systems. both total bacterial ... | 1999 | 10063620 |
| production of specific monoclonal antibodies to aspergillus species and their use in immunohistochemical identification of aspergillosis. | two anti-aspergillus murine monoclonal antibodies (mabs), designated 164g and 611f, have been produced; both specifically recognize cytoplasmic antigens of a. fumigatus, a. flavus, and a. niger by enzyme-linked immunosorbent assay. the mabs can identify aspergillus spp. both in frozen sections by immunofluorescence and in paraffin-embedded clinical specimens by immunofluorescence and immunoperoxidase staining. | 1999 | 10074559 |
| fungicidal and binding properties of the natural peptides cecropin b and dermaseptin. | in vitro fungicidal properties of cecropin b and dermaseptin were explored using non-germinating and germinating conidia from aspergillus flavus, a. fumigatus, a. niger, fusarium n2oniliforme and f oxysporum. cecropin b produced ld50 values for germinating a. flavus, a. fumigatus and a. niger conidia of 30, 0.5 and 2.0 microm, respectively, while dermaseptin gave ld50 values of 4.0, 0.05 and 2.0 microm, respectively. cecropin b produced an ld50 value of 0.2 microm for non-germinating f. monilifo ... | 1998 | 10075498 |
| aspergillus fumigatus catalases: cloning of an aspergillus nidulans catalase b homologue and evidence for at least three catalases. | the presence of catalases in the water soluble fractions of three aspergillus fumigatus strains was investigated using non-denaturing and denaturing polyacrylamide gel electrophoresis and western analysis. using non-denaturing polyacrylamide gel electrophoresis and staining for catalase activity, three separate catalases were identified. an a. fumigatus catalase gene (catb) was cloned from genomic dna using the aspergillus niger catr gene as a probe. polyclonal antibodies were raised to a glutat ... | 1999 | 10076909 |
| a group of alpha-1,4-glucan lyases and their genes from the red alga gracilariopsis lemaneiformis: purification, cloning, and heterologous expression. | we present here the first report of a group of alpha-1,4-glucan lyases (ec 4.2.2.13) and their genes. the lyases produce 1, 5-anhydro-d-fructose from starch and related oligomers and polymers. the enzymes were isolated from the red alga gracilariopsis lemaneiformis from the pacific coasts of china and usa, and the atlantic coast of venezuela. three lyase isozymes (glq1, glq2 and glq3) from the chinese subspecies, two lyase isozymes (gls1 and gls2) from the usa subspecies and one lyase (gla1) fro ... | 1999 | 10082967 |
| mono- and sesquiterpenes and antifungal constituents from artemisia species. | in addition to beta-sitosterol and alpha-amyrin detected in all the investigated species, the extract of the aerial parts of artemisia giraldii var. giraldii gave stigmasterol, daucosterol, sesamine, luteolin, eupafolin, hispidulin, eupatilin, belamcanidin, pinitol, artemin, ridentin, and a new antifungal monoterpene (named santolinylol) while that of the aerial parts of a. mongolica afforded sesamine, eupafolin, eupatilin, matricarin, and a new germacranolide (3-oxo-11 alpha h-germacra-1(10)e,4 ... | 1999 | 10083848 |
| molecular cloning, characterization, and expression of the m antigen of histoplasma capsulatum. | the major diagnostic antigens of histoplasma capsulatum are the h and m antigens, pluripotent glycoproteins that elicit both humoral and t-cell-mediated immune responses. these antigens may play a role in the pathogenesis of histoplasmosis. m antigen is considered immunodominant because antibodies against it are the first precipitins to arise in acute histoplasmosis and are commonly present during all phases of infection. the biological activity of monomolecular m antigen and its ability to elic ... | 1999 | 10085041 |
| role of glycosylation in the functional expression of an aspergillus niger phytase (phya) in pichia pastoris. | economical and thermostable phytase enzymes are needed to release phytate-phosphorus in plant foods for human and animal nutrition and to reduce phosphorus pollution of animal waste. our objectives were to determine if a methylotrophic yeast, pichia pastoris, was able to express a phytase gene (phya) from aspergillus niger efficiently and if suppression of glycosylation by tunicamycin affected its functional expression. the gene (1.4 kb) was inserted into an expression vector ppiczalphaa with a ... | 1999 | 10087168 |
| effect of spumol k on the ultrastructure of aspergillus niger strains sensitive or resistant to toxic compounds of beet molasses. | aspergillus niger strains sensitive and resistant to toxic compounds of beet molasses grown in the presence of spumol k were the object of the present studies. the antifoamer used diminished the number of mitochondria in both groups of strains and caused the reduction of their cristae in the sensitive ones. the disturbances in the ultrastructure of nucleus and mitochondria appeared mostly in sensitive strains. on the other hand, spumol k presence in resistant strains not only increased the numbe ... | 1999 | 10091948 |
| cloning, sequencing, and expression of an escherichia coli acid phosphatase/phytase gene (appa2) isolated from pig colon. | bacterial strains were isolated from the pig colon to screen for phytase and acid phosphatase activities. among 93 colonies, colony 88 had the highest activities for both enzymes and was identified as an escherichia coli strain. using primers derived from the e. coli ph 2.5 acid phosphatase appa sequence (dassa et al. (1990), j. bacteriol. 172, 5497-5500), we cloned a 1482 bp dna fragment from the isolate. in spite of 95% homology between the sequenced gene and the appa, 7 amino acids were diffe ... | 1999 | 10092520 |
| kinetic characterization of aspergillus niger n400 endopolygalacturonases i, ii and c. | endopolygalacturonases i, ii and c isolated from recombinant aspergillus niger strains 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). apparent vmax values using polygalacturonate as a substrate at the ph optimum, ph 4.1, were calculated as 13.8 mukat.mg-1, 36.5 mukat.mg-1 and 415 nkat.mg-1 for endopolygalacturonases i, ii and c, respectively. k(m) values were < 0.15 mg.ml ... | 1999 | 10092840 |
| comparison of kinetic properties of amine oxidases from sainfoin and lentil and immunochemical characterization of copper/quinoprotein amine oxidases. | kinetic properties of novel amine oxidase isolated from sainfoin (onobrychis viciifolia) were compared to those of typical plant amine oxidase (ec 1.4.3.6) from lentil (lens culinaris). the amine oxidase from sainfoin was active toward substrates, such as 1,5-diaminopentane (cadaverine) with k(m) of 0.09 mm and 1,4-diaminobutane (putrescine) with k(m) of 0.24 mm. the maximum rate of oxidation for cadaverine at saturating concentration was 2.7 fold higher than that of putrescine. the amine oxidas ... | 1999 | 10092944 |
| optimization and stability of glucoamylase production by recombinant strains of aspergillus niger in chemostat culture. | when grown on a medium containing 5 g maltodextrin l-1, aspergillus niger transformant n402[pab6-10]b1, which has an additional 20 copies of the glucoamylase (glaa) gene, produced 320 +/- 8 mg (mean +/- s.e.) glucoamylase (gam) l-1 in batch culture and 373 +/- 9 mg gam l-1 in maltodextrin-limited chemostat culture at a dilution rate of 0.13 h-1. these values correspond to specific production rates (qp) of 5.6 and 16.0 mg gam [g biomass]-1 h-1, respectively. in maltodextrin-limited chemostat cult ... | 1998 | 10099354 |
| validation of a model describing two-dimensional heat transfer during solid-state fermentation in packed bed bioreactors. | a two-dimensional heat transfer model was validated against two experimental studies from the literature which describe the growth of aspergillus niger during solid-state fermentation in packed bed bioreactors. with the same set of model parameters, the two-dimensional model was able to describe both radial temperature gradients, which dominated in one of the studies, and axial temperature gradients, which dominated in the other study. the sensitivity of the model predictions to the characterist ... | 1998 | 10099483 |
| crosslinking of glucoamylases via carbohydrates hardly affects catalysis but impairs stability. | mild oxidation of glucoamylases from aspergillus niger (e.c.3.2.1.3. ) with periodate, followed by incubation with adipic acid dihydrazide, covalently linked enzyme molecules via their glycosyl groups. size exclusion chromatography demonstrated and electron microscopy confirmed the formation of tetramers and octamers. heat inactivation studies in the range of 60 degrees to 80 degrees c indicated that, in contrast to a priori expectations, crosslinking via the carbohydrates decreased rather than ... | 1999 | 10099626 |
| first evaluation of the brazilian microorganisms biocatalytic potential. | the biocatalytic potential of two novel brazilian strains of aspergillus niger and rhodotorula glutinis, revealed enantioselective epoxide hydrolase activity in the asymmetrization of meso-epoxide and monosubstituted epoxides respectively. these two types of oxirane derivatives are not usually good substrates for biocatalytic enantioselective conversion. | 1999 | 10101864 |
| an aureobasidin a resistance gene isolated from aspergillus is a homolog of yeast aur1, a gene responsible for inositol phosphorylceramide (ipc) synthase activity. | the aur1 gene of saccharomyces cerevisiae, mutations in which confer resistance to the antibiotic aureobasidin a, is necessary for inositol phosphorylceramide (ipc) synthase activity. we report the molecular cloning and characterization of the aspergillus nidulans aura gene, which is homologous to aur1. a single point mutation in the aura gene of a. nidulans confers a high level of resistance to aureobasidin a. the a. nidulans aura gene was used to identify its homologs in other aspergillus spec ... | 1999 | 10102364 |
| availability of phosphorus and sulfur of insecticide origin by fungi. | thirteen fungal species isolated from soil treated with pesticides were tested for their ability to mineralize and degrade three organophosphate insecticides currently used in egypt (cyolan, malathion and dursban) in liquid media free from phosphorus (p) and sulfur (s). all fungal species grew successfully on the culture media treated with the three used doses of insecticides (10, 50 and 100 ppm active ingredient) but the growth rate varied with the species, the insecticide and the doses. at 10 ... | 1998 | 10192894 |
| possibility for discriminating between two representative non two-state thermal unfolding models of proteins by dsc. | possible differences between two representative non two-state thermal unfolding mechanisms of protein are discussed concerning differential scanning calorimetry. numerical simulations showed that, by dsc measurement, it is hard to discriminate between the independent model, which assumes independent unfolding domains in a protein, and the sequential model, which assumes intermediate(s) between native and denatured states, especially when values of molecular weight, denaturation enthalpy, and dif ... | 1999 | 10192925 |
| comparison of e-test and broth microdilution methods for antifungal drug susceptibility testing of molds. | we compared the e test with a broth microdilution method, performed according to national committee for clinical laboratory standards document m27-a guidelines, for determining the in vitro susceptibilities of 90 isolates of pathogenic molds (10 absidia corymbifera, 10 aspergillus flavus, 10 aspergillus fumigatus, 10 aspergillus niger, 10 aspergillus terreus, 10 exophiala dermatitidis, 10 fusarium solani, 10 scedosporium apiospermum, 5 scedosporium prolificans, and 5 scopulariopsis brevicaulis). ... | 1999 | 10203509 |
| pseudoepidemic of aspergillus niger infections traced to specimen contamination in the microbiology laboratory. | we report a pseudo-outbreak of aspergillus niger that followed building construction in our clinical microbiology laboratory. because outbreaks of invasive aspergillosis have been linked to hospital construction, strategies to minimize dust in patient care areas are common practice. we illustrate that the impact of false-positive cultures on patient care should compel laboratories to prevent specimen contamination during construction. | 1999 | 10203538 |
| sequencing of partially methyl-esterified oligogalacturonates by tandem mass spectrometry and its use to determine pectinase specificities. | complex mixtures of acidic oligosaccharides were produced by enzymatic digestion of partially methyl-esterified pectin with aspergillus niger pectin lyase, endopolygalacturonase ii, and exopolygalacturonase. to determine the specificities of these pectolytic enzymes toward non-esterified and methyl-esterified galacturonic acid residues, we have studied the methyl esterification patterns of selected oligomers in unseparated pectin digests. collision-induced dissociation in a nanoelectrospray ioni ... | 1999 | 10204041 |
| oxidation of medium-chain acyl-coa esters by extracts of aspergillus niger: enzymology and characterization of intermediates by hplc. | the activities of beta-oxidation enzymes were measured in extracts of glucose- and triolein-grown cells of aspergillus niger. growth on triolein stimulated increased enzyme activity, especially for acyl-coa dehydrogenase. no acyl-coa oxidase activity was detected. hplc analysis after incubation of triolein-grown cell extracts with decanoyl-coa showed that beta-oxidation was limited to one cycle. octanoyl-coa accumulated as the decanoyl-coa was oxidized. beta-oxidation enzymes in isolated mitocho ... | 1999 | 10206707 |
| correlation between fungi isolated from burn wounds and burn care units. | a comparison was made prospectively between fungal isolates from patients and burn care units. aspergillus niger was the most frequent isolate in both patients and burn care units whereas ulocladium was the commonest isolate in the control group. aspergillus terreus, penicillium and zygomycetes, which were recovered from burned patients, were also found more frequently in the burn care units than in the control group (other areas in the hospital). these findings indicate a potential risk of fung ... | 1999 | 10208389 |
| [fungal flora in chicken stalls and its etiopathogenic importance for humans and animals]. | in order to find out the mycoflora prevailing in chicken pens, and to appreciate the health hazards for employees (incl. veterinarians) and animals, twenty litter samples and 6 sedimented dust trials were analysed mycologically. the following results were found: bedding and dust samples all contained between 3.57 and 1.30 x 10(7) c.f.u./g dw. the commonest fungus is a. fumigatus with 3.41 x 10(4) - 1.30 x 10(7) c.f.u./g dw in bedding and 2.70 x 10(5) - 3.30 x 10(6) c.f.u./g dw in sedimented dust ... | 1999 | 10209909 |
| environmental factors and nutritional utilization patterns affect niche overlap indices between aspergillus ochraceus and other spoilage fungi. | the total number, and the type of c source utilized in common by an ochratoxin producing strain of aspergillus ochraceus and six other spoilage fungi varied with the range used (95, biolog gn plates, or 18 major c sources found in maize). the niche size and niche overlap index (noi) were markedly influenced by water availability (water activity, aw) and temperature. with freely available water (0.995 aw) there was ecological similarity between a. ochraceus, a. alternata, a. candidus and a. flavu ... | 1999 | 10212444 |
| nasosinus aspergillosis in sudanese patients: clinical features, pathology, diagnosis, and treatment. | the objective of this study was a prospective analysis of the clinical features, pathology, diagnosis, and treatment of patients treated between 1993 and 1996 for nasosinus aspergillosis in the sudan. | 1999 | 10212875 |
| conformational transitions accompanying oligomerization of yeast alcohol oxidase, a peroxisomal flavoenzyme. | alcohol oxidase (ao) is a homo-octameric flavoenzyme which catalyzes methanol oxidation in methylotrophic yeasts. ao protein is synthesized in the cytosol and subsequently sorted to peroxisomes where the active enzyme is formed. to gain further insight in the molecular mechanisms involved in ao activation, we studied spectroscopically native ao from hansenula polymorpha and pichia pastoris and three putative assembly intermediates. fluorescence studies revealed that both trp and fad are suitable ... | 1999 | 10213606 |
| biotransformation of (1-phenyl)ethyl hydroperoxide with aspergillus niger: a model study on enzyme selectivity and on the induction of peroxidase activity. | the biocatalytic enantioselective reduction of (1-phenyl)ethyl hydroperoxide (1) by the fungus aspergillus niger to the corresponding alcohol 2 involves a multi-enzyme biotransformation of the hydroperoxide 1, as revealed by the change in the enantioselectivity as a function of incubation times. this unusual behavior is not exhibited by other fungi and seems to be restricted to a. niger. furthermore, the peroxidase and other oxidoreductase activities of a. niger depend on the availability of met ... | 1999 | 10216240 |
| 1.8 and 1.9 a resolution structures of the penicillium amagasakiense and aspergillus niger glucose oxidases as a basis for modelling substrate complexes. | glucose oxidase is a flavin-dependent enzyme which catalyses the oxidation of beta-d-glucose by molecular oxygen to delta-gluconolactone and hydrogen peroxide. the structure of the enzyme from aspergillus niger, previously refined at 2.3 a resolution, has been refined at 1.9 a resolution to an r value of 19.0%, and the structure of the enzyme from penicillium amagasakiense, which has 65% sequence identity, has been determined by molecular replacement and refined at 1.8 a resolution to an r value ... | 1999 | 10216293 |
| separation and direct detection of raw and gelatinized starch hydrolyzing activities of glucoamylase on isoelectric focusing gels. | a procedure to detect raw and gelatinized starch activities of glucoamylase on isoelectric focusing (ief) gels by using 2, 3, 5-triphenyltetrazolium chloride is described. the reagent reacts with the reducing group of glucose released by glucoamylase from the substrate starch. using the reaction, production of glucoamylase by aspergillus niger was detected on 10% ief gels within a ph range of 2.5-9.5. since the method can detect raw and gelatinized starch activities of glucomylase associated wit ... | 1999 | 10217158 |
| study of the glucoamylase promoter in aspergillus niger using green fluorescent protein. | an aspergillus niger strain expressing a red-shifted green fluorescent protein (gfp) in the cytoplasm under the control of the glucoamylase promoter (pgiaa) was characterized with respect to its physiology and morphology. although xylose acted as a repressor carbon source during batch cultivations, pgiaa-driven gfp expression by the glucoamylase promoter could be demonstrated in xylose-limited continuous cultures. in these cultivations, the xylose concentration was therefore too low to cause rep ... | 1999 | 10217507 |
| the abfb gene encoding the major alpha-l-arabinofuranosidase of aspergillus nidulans: nucleotide sequence, regulation and construction of a disrupted strain. | using a dna fragment containing the aspergillus niger abfb gene as a probe, the homologous aspergillus nidulans gene, designated abfb, has been cloned from a genomic library containing size-selected hindiii fragments. the nucleotide sequence of the a. nidulans abfb gene shows strong homology with the a. niger abfb, trichoderma reesei abf-1 and trichoderma koningii alpha-l-arabinofuranosidase/beta-xylosidase genes. regulation of abfb expression has been investigated in cultures induced with l-ara ... | 1999 | 10217508 |
| the starch-binding domain from glucoamylase disrupts the structure of starch. | the full-length glucoamylase from aspergillus niger, g1, consists of an n-terminal catalytic domain followed by a semi-rigid linker (which together constitute the g2 form) and a c-terminal starch-binding domain (sbd). g1 and g2 both liberate glucose from insoluble corn starch, although g2 has a rate 80 times slower than g1. following pre-incubation of the starch with sbd, the activity of g1 is uniformly reduced with increasing concentrations of sbd because of competition for binding sites. howev ... | 1999 | 10218582 |
| influence of microbial concentration on the rheology of non-newtonian fermentation broths. | the objective of this study was to quantify the effect of fungal biomass concentration on the rheology of non-newtonian fermentation systems. batch fermentations of penicillium chrysogenum were carried out with glucose as the sole carbon source. the flow behavior of the system was characterized at various fermentation times and was adequately described by the power-law model. the apparent viscosity of the fermentation broth was significantly affected by biomass concentrations in the fermenter. f ... | 1999 | 10222579 |
| expression of two major chitinase genes of trichoderma atroviride (t. harzianum p1) is triggered by different regulatory signals. | regulation of the expression of the two major chitinase genes, ech42 (encoding the chit42 endochitinase) and nag1 (encoding the chit73 n-acetyl-beta-d-glucosaminidase), of the chitinolytic system of the mycoparasitic biocontrol fungus trichoderma atroviride (= trichoderma harzianum p1) was investigated by using a reporter system based on the aspergillus niger glucose oxidase. strains harboring fusions of the ech42 or nag1 5' upstream noncoding sequences with the a. niger goxa gene displayed a gl ... | 1999 | 10223970 |
| expression of an aspergillus niger phytase gene (phya) in saccharomyces cerevisiae. | phytase improves the bioavailability of phytate phosphorus in plant foods to humans and animals and reduces phosphorus pollution of animal waste. our objectives were to express an aspergillus niger phytase gene (phya) in saccharomyces cerevisiae and to determine the effects of glycosylation on the phytase's activity and thermostability. a 1.4-kb dna fragment containing the coding region of the phya gene was inserted into the expression vector pyes2 and was expressed in s. cerevisiae as an active ... | 1999 | 10223979 |
| a sandwiched-culture technique for evaluation of heterologous protein production in a filamentous fungus. | aspergillus niger is known for its efficient excretion machinery. however, problems have often arisen in obtaining high amounts of heterologous proteins in the culture medium. here we present a quick method using sandwiched colonies to evaluate transgenic strains for secretion of heterologous proteins. expressing the abh1 hydrophobin of agaricus bisporus in a. niger, we showed that low production levels of the heterologous protein are probably due to extracellular proteolytic degradation of the ... | 1999 | 10224030 |
| the specificity of polygalacturonase-inhibiting protein (pgip): a single amino acid substitution in the solvent-exposed beta-strand/beta-turn region of the leucine-rich repeats (lrrs) confers a new recognition capability. | two members of the pgip gene family (pgip-1 and pgip-2) of phaseolus vulgaris l. were expressed separately in nicotiana benthamiana and the ligand specificity of their products was analysed by surface plasmon resonance (spr). polygalacturonase-inhibiting protein-1 (pgip-1) was unable to interact with pg from fusarium moniliforme and interacted with pg from aspergillus niger; pgip-2 interacted with both pgs. only eight amino acid variations distinguish the two proteins: five of them are confined ... | 1999 | 10228150 |
| post-traumatic endophthalmitis: causative organisms and visual outcome. | post-traumatic endophthalmitis makes up a distinct subset of intraocular infections. the purpose of the present study was to identify the causative organisms and record the visual outcome after infectious endophthalmitis in eyes with penetrating trauma. | 1999 | 10230588 |
| microbial conversion of jasmonates-hydroxylations by aspergillus niger. | aspergillus niger is able to hydroxylate the pentenyl side chain of (-)-jasmonic acid (ja) leading to (11s)-(-)-hydroxy-ja/(11r)- (-)-hydroxy-ja (2:1) and (-)-11,12-didehydro-ja. methyl (-)-jasmonate (ja-me) is converted upon hydrolysis. during prolonged cultivation or at non-optimized isolation procedures, the 11-hydroxy-(9z)-pentenyl side chain may isomerize to (10e)-9-hydroxy- and (9e)-11-hydroxy-compounds by allylic rearrangement. the fungus hydroxylates (+/-)-9,10-dihydro-ja at position c-1 ... | 1999 | 10234859 |
| thermodynamics of reversible and irreversible unfolding and domain interactions of glucoamylase from aspergillus niger studied by differential scanning and isothermal titration calorimetry. | the stability of three forms of glucoamylase from aspergillus niger has been investigated by differential scanning and isothermal titration calorimetry: glucoamylase 1 (ga1), which consists of a catalytic domain and a starch-binding domain (sbd) connected by a heavily o-glycosylated linker region; glucoamylase 2 (ga2), which lacks sbd; and a proteolytically cleaved glucoamylase (gacd), which contains the catalytic domain and part of the linker region. the structures of the catalytic domain with ... | 1999 | 10320360 |
| purification and properties of three cellobiases from aspergillus niger a20. | three cellobiases, here called cellobiase a, b, and c, from the culture filtrate of aspergillus niger a20, were purified by precipitation with ammonium sulphate, gel filtration through sephadex g-75, and column chromatography of deae-cellulose. the purified enzymes were homogeneous on polyacrylamide disk electrophoresis. the mol wt of the purified enzymes were estimated by sds-gel electrophoresis to be 88,000, 80,000, and 71,000 for cellobiases a, b, and c, respectively. the enzymes were active ... | 1999 | 10327588 |
| different sensitivity of recombinant aspergillus niger phytase (r-phya) and escherichia coli ph 2.5 acid phosphatase (r-appa) to trypsin and pepsin in vitro. | proteolysis of two purified recombinant enzymes, namely, the aspergillus niger phytase (r-phya) and the escherichia coli ph 2.5 acid phosphatase (r-appa), by pepsin and trypsin was investigated in this study. after r-phya and r-appa were incubated with different concentrations of pepsin or trypsin, their residual phytase activities and amounts of inorganic phosphorus released from soybean meal were determined. both enzymes retained more than 85% of their original activities at the trypsin/phytas ... | 1999 | 10328821 |
| crystal structure of aspergillus niger ph 2.5 acid phosphatase at 2. 4 a resolution. | the crystal structure of aspergillus niger ph 2.5 acid phosphatase (ec 3.1.3.2) has been determined at 2.4 a resolution. in the crystal, two dimers form a tetramer in which the active sites are easily accessible to substrates. the main contacts in the dimer come from the n termini, each lying on the surface of the neighbouring molecule. the monomer consists of two domains, with the active site located at their interface. the active site has a highly conserved catalytic center and a charge distri ... | 1999 | 10329192 |
| simultaneous production of catalase, glucose oxidase and gluconic acid by aspergillus niger mutant. | the production of gluconic acid, extracellular glucose oxidase and catalase in submerged culture by a number of biochemical mutants has been evaluated. optimization of stirrer speed, time cultivation and buffering action of some chemicals on glucose oxidase, catalase and gluconic acid production by the most active mutant, am-11, grown in a 3-l glass bioreactor was investigated. three hundred rpm appeared to be optimum to ensure good growth and best glucose oxidase production, but gluconic acid o ... | 1998 | 10333558 |