| immunochemical detection of ochratoxin a in black aspergillus strains. | one hundred and fifty-seven strains belonging to aspergillus section nigri were tested for ochratoxin a production using three different methods: a relatively new immunochemical method based on an enzyme-linked immunosorbent assay (elisa), thin-layer chromatography (tlc) and high-performance liquid chromatography (hplc). the monoclonal antibody-based elisa technique was successfully used to screen for low levels of ochratoxin a in the black aspergilli without concentrating the culture filtrates. ... | 1996 | 8981783 |
| control of pellet morphology of filamentous fungi in fluidized bed bioreactors by means of a pulsing flow. application to aspergillus niger and phanerochaete chrysosporium. | the application of a pulsing flow to fluidized-bed bioreactors in order to control pellet morphology of filamentous fungi was investigated. the operation at an optimum pulsation frequency allowed two effects: a narrower pellet size distribution which improves fluidization quality, and an enhanced production of citric acid by aspergillus niger and manganese peroxidase by phanerochaete chrysosporium. in the case of a. niger, the pellet diameter corresponding to the pulsed system operated at 0.35 s ... | 1996 | 8987486 |
| o-demethylation of 7,7'-epoxylignans by aspergillus niger. | biotransformation of the 7,7'-epoxylignans, (+)-veraguensin, (+)-galbelgin and galgravin by aspergillus niger has been investigated. these lignans were converted to their corresponding 4,4'-o-demethyl derivatives, (+)-verrucosin, (+)-fragransin a2 and nectandrin b. | 1996 | 8987506 |
| an expression system based on the promoter region of the aspergillus awamori 1,4-beta-endoxylanase a gene. | a new, highly inducible fungal promoter derived from the aspergillus awamori 1,4-beta-endoxylanase a (exla) gene is described. induction analysis, carried out with the wild-type strain in shake flasks, showed that exla expression in regulated at the transcriptional level. using a beta-glucuronidase (uida) reporter strategy, d-xylose was shown to be an efficient inducer of the exla promoter, whereas sucrose or maltodextrin were not. upon d-xylose induction, the exla promoter was threefold more ef ... | 1996 | 8987532 |
| a two-step bioconversion process for vanillin production from ferulic acid combining aspergillus niger and pycnoporus cinnabarinus. | a two-step bioconversion process of ferulic acid to vanillin was elaborated combining two filamentous fungi, aspergillus niger and pycnoporus cinnabarinus. in the first step, a. niger transformed ferulic acid to vanillic acid and in the second step vanillic acid was reduced to vanillin by p. cinnabarinus. ferulic acid metabolism by a. niger occurred essentially via the propenoic chain degradation to lead to vanillic acid, which was subsequently decarboxylated to methoxyhydroquinone. in 3-day-old ... | 1996 | 8987621 |
| partitioning of beta-mannanase and alpha-galactosidase from aspergillus niger in ucon/reppal aqueous two-phase systems and using temperature-induced phase separation. | enzyme partitioning and recovery with a new aqueous two-phase system based on commercially available hydroxypropyl starch reppal pes 200 and the thermo-separating polymer ucon 50-hb-5100 was studied. ucon is an ethylene oxide-propylene oxide random copolymer. a culture supernatant of aspergillus niger containing extracellular beta-mannanase and alpha-galactosidase was partitioned in two steps. the primary aqueous two-phase system contained ucon and reppal as phase forming polymers. the effect on ... | 1996 | 8987681 |
| antimicrobial effects of hydrophilic extracts of pelargonium species (geraniaceae). | methanolic extracts of representative species and cultivars of pelargonium (geraniaceae) were assessed for activity against 25 different species of bacteria and aspergillus niger. all samples were active against at least 18 bacterial species and some were active against all 25 species, although there was very poor antifungal action. antioxidant action was very pronounced, and this together with the strong antibacterial activity indicates that there is a potential usage in the food or other indus ... | 1996 | 8987691 |
| associated mycoflora of rye bread. | penicillium roqueforti (27%), p. corylophilum (20%) and eurotium species (15%) made up the important mycoflora associated with rye bread on 3425 identified fungi isolates. these fungi were dominant as spoilers of packaged rye bread in almost every month of a 4 year investigation. penicillium decumbens (3%), paecilomyces variotti (8%) and aspergillus flavus (5%) were found more rarely, but were the major species found over periods of a few months. penicillium commune (5%), p. solitum (4%), a. nig ... | 1996 | 8987693 |
| optimization of the benzoate-inducible benzoate p-hydroxylase cytochrome p450 enzyme system in aspergillus niger. | introduction in the fungus aspergillus niger of multiple copies of the a. niger bpha gene, encoding the cytochrome p450 enzyme benzoate p-hydroxylase, did not result in increased activities of this enzyme [gorcom rfm van, et al. mol gen genet (1990) 223: 192-197] probably because of low expression levels of the gene encoding the second component of the microsomal cytochrome p450 enzyme system, cytochrome p450 reductase. for improvement of this and other cytochrome-p450-dependent reactions, a. ni ... | 1996 | 8987724 |
| a new glucose oxidase from aspergillus niger: characterization and regulation studies of enzyme and gene. | a new glucose oxidase from aspergillus niger was isolated and characterized. the enzyme showed different kinetic and stability characteristics when compared to a commercially available batch of a. niger glucose oxidase. the gene encoding the new glucose oxidase was isolated and dna sequence analysis of the coding region showed 80% identity to the sequence of a glucose oxidase gene previously published. however, the similarity of the non-coding sequences up- and downstream of the open reading fra ... | 1996 | 8987726 |
| two components of cell-bound isopullulanase from aspergillus niger atcc 9642--their purification and enzymatic properties. | cell-bound isopullulanase (pullulan 4-glucanohydrolase: ec 3.2.1.57, ipu) from aspergillus niger atcc9642 [y. sakano et al., denpun kagaku, 37, 39-41 (1990)] was separated into two active components, ipu f1 (pi = 5.0) and ipu f2 (pi = 4.9), using a mono-p hr 5/20 column. the substrate specificity on pullulan and panose, specific activity, optimum ph, ph stability, and susceptibility to certain chemical reagents were similar between ipu f1 and ipu f2. ipu f1 and f2 had an identical n-terminal ami ... | 1996 | 8987855 |
| purification and characterization of glucoamylase produced by aspergillus niger in solid state fermentation. | glucoamylases produced by aspergillus niger grown on wheat brain in solid cultures were purified. four different forms, ga i, ga i', ga ii and ga iii, were found having apparent molecular weights of 112,000, 104,000, and 74,000 and 61,000 da respectively. the enzymes are glycoproteins with a carbohydrate content of 16%, and optimal activity at 60 degrees c and ph 4.4. activity was strongly inhibited by hg2+ while mn2+ and fe2+ were stimulatory. the km values for the degradation of starch and mal ... | 1996 | 8987901 |
| effect of microbial phytase on cadmium accumulation in pigs. | 2 x 6 pigs continuously housed in metabolic cages from 25-100 kg weight were fed n-reduced diets based on barley, maize and soybean meal. diet i (control) contained in fm (fresh matter) 0.56%, 0.48% and 0.46% p (feeding phases a: 25-50 kg, b: 50-75 kg, c: 75-100 kg weight) and 0.76%, 0.71% and 0.68% ca. diet ii was low in p (0.46%, 0.40%, 0.32%) and ca (0.69%, 0.62%, 0.52%) and 800 u aspergillus-phytase per kg were added. analyzed cadmium concentrations in diet i were 23.4, 19.9 and 13.7 microgr ... | 1996 | 8988314 |
| cloning and function determination of promoter region of glucoamylase gene from aspergillus niger t21. | a 850 bp fragment of the 5' flanking region of the glucoamylase gene (glaa) was synthesized from a. niger t21 genome using pcr. the function detection vector was constructed by fusing this fragment to e. coli hygromycin b phosphotransferase gene (hph) and was used to transform a. niger. the high hygromycin resistance transformants thus obtained verified that the synthesized fragment functioned as a promoter in filamentous fungi. southern blot analysis showed the hph gene has been integrated into ... | 1996 | 8988359 |
| steady-state kinetic and calorimetric studies on the binding of aspergillus niger glucoamylase with gluconolactone, 1-deoxynojirimycin, and beta-cyclodextrin. | binding equilibria of aspergillus niger glucoamylase with its several ligands were observed to analyze the binding modes of the ligands. steady-state kinetic studies using p-nitrophenyl alpha-glucoside as a substrate showed that 1-deoxynojirimycin, which is a mixed type inhibitor for rhizopus glucoamylase, was a competitive type inhibitor bound at the active site of the enzyme, but gluconolactone, which is also a mixed type inhibitor for rhizopus glucoamylase, was a non-competitive type inhibito ... | 1996 | 8988638 |
| lucigenin (bis-n-methylacridinium) as a mediator of superoxide anion production. | lucigenin (bis-n-methylacridinium) (luc2+) has frequently been used for the luminescent detection of o2-. in fact, the pathway leading to this luminescence requires univalent reduction of luc2+ to luch.+ followed by formation of an unstable dioxetane by reaction of luch.+ with o2-. it is now shown that luch.+ rapidly autooxidizes and so produces o2-. luc2+ can thus mediate o2- production in systems, such as glucose plus glucose oxidase, in which there is ordinarily no o2- production. luc2+ lumin ... | 1997 | 8990275 |
| dna topoisomerase inhibitors as antifungal agents. | | 1994 | 8996610 |
| sorption of cadmium by filamentous soil fungi. | the article presents the evaluation of the short-term sorption of cd by selected soil fungi. the freundlich adsorption isotherm method for metal sorption modelling was applied. fungal strains belonging to two classes, zygomycetes and ascomycetes, were used. altogether, six species from ascomycetes (a. niger, a. nidulans, ps. boydii, t. koningii, p. janthinellum, p. verrucosum) and three from zygomycetes (r. rhizopodiformis, r. oryzae, r. pusillus) were examined. these fungi were selected for exp ... | 1996 | 8997697 |
| synthesis and antifungal activities of myristic acid analogs. | myristic acid analogs that are putative inhibitors of n-myristoyl-transferase were tested in vitro for activity against yeasts (saccharomyces cerevisiae, candida albicans, cryptococcus neoformans) and filamentous fungi (aspergillus niger). several (+/-)-2-halotetradecanoic acids including (+/-)-2-bromotetradecanoic acid (14c) exhibited potent activity against c. albicans (mic = 39 microm), c. neoformans (mic = 20 microm), s. cerevisiae (mic = 10 microm), and a. niger (mic < 42 microm) in rpmi 16 ... | 1996 | 8997896 |
| arabinoxylan degradation by fungi: characterization of the arabinoxylan-arabinofuranohydrolase encoding genes from aspergillus niger and aspergillus tubingensis. | the genes encoding the enzyme arabinoxylan arabinofuranohydrolase, which releases l-arabinose from arabinoxylan, have been cloned from the closely related fungi aspergillus niger and aspergillus tubingensis and were shown to be functional in a. niger. integration of multiple copies in the genome resulted in over-expression of the enzymes. the arabinofuranohydrolases encoded comprise 332 amino acids and have 94% amino acid identity. their primary structure is not related to those of other alpha-l ... | 1997 | 9000377 |
| the transposable element tan1 of aspergillus niger var. awamori, a new member of the fot1 family. | aspergillus niger var. awamori has transposable elements that we refer to as vader and tan1 (transposon a. niger). vader was identified by screening unstable nitrate reductase (niad) mutants for insertions. four of the isolated niad mutants were shown to contain a small insertion element. this 437 bp insertion element, vader, is flanked by 44 bp inverted repeats (ir) and is present in approximately 15 copies in the genomes of two a. niger strains examined. a synthetic 44 bp oligomer of the inver ... | 1996 | 9003286 |
| the aspergillus niger gcn4 homologue, cpca, is transcriptionally regulated and encodes an unusual leucine zipper. | the general control transcriptional regulator gene cpca of aspergillus niger was cloned by complementation of a saccharomyces cerevisiae delta gcn4 mutant strain. the encoded protein conferred resistance to amino acid analogues when expressed in yeast. disruption of cpca in a. niger resulted in a strain which is sensitive towards 3-aminotriazole and fails to respond to amino acid starvation, cpca encodes a transcript of approximately 2400 nucleotides in length that includes a 5' leader region of ... | 1997 | 9004217 |
| metabolism of goniothalamin in animal and microbial system. | of the twenty microorganisms screened for metabolism of goniothalamin only streptomyces aurofaciens atcc 10762 and nocardia species nrrl 5646 produced two metabolites, 3,4-dihydrogoniothalamin and 3,4,7,8 tetrahydrogoniothalamin. the identity of the isolated metabolites were established using tlc, hplc, ms, ir, and 1h- and 13c-nmr spectroscopy. in addition, the substrate had been transformed into two unknown metabolites by aspergillus niger atcc 11394 and septomyxa affinis atcc 6737 in low yield ... | 1996 | 9004738 |
| the filamentous fungus aspergillus niger contains two "differentially regulated" trehalose-6-phosphate synthase-encoding genes, tpsa and tpsb. | two genes encoding trehalose-6-phosphate synthase were cloned from aspergillus niger. tpsa was cloned using the saccharomyces cerevisiae ggs1/tps1 gene as a probe. it encodes a 517-amino acid polypeptide with 64-70% similarity to trehalose-6-phosphate synthase of s. cerevisiae, kluyveromyces lactis, and schizosaccharomyces pombe. its transcription occurs constitutively and is enhanced on carbon-derepressing carbon sources, coinciding with the presence of a crea-binding nucleotide motif in the 5' ... | 1997 | 9006911 |
| otomycosis--a clinico-mycological study and efficacy of mercurochrome in its treatment. | a total of 110 patients of symptomatic otomycosis was investigated, prospectively. aural swabs were collected on 1st, 7th and 14th day and examined by direct microscopy and culture for fungi. of these, 80 patients found to be having pure fungal infection, were taken up for mycological and therapeutic study. fungi belonging to genus aspergillus were isolated in 76 (95.0%) patients of which aspergillus niger was the commonest isolate in 46 (57.5%), followed by a. flavus in 27 (33.7%), a. fumigatus ... | 1996 | 9008878 |
| influence of zinc oxide on aspergillus species: a possible cause of local, non-invasive aspergillosis of the maxillary sinus. | recently the appearance of radiopaque 'concrements' in the maxillary sinus was reported. these radiodense objects could be identified as root-filling material for teeth of the upper jaw containing zinc oxide. this suggested that excess root-filling material containing zinc oxide in the maxillary sinus could favour the formation of a local, non-invasive aspergillosis. to verify this hypothesis in vitro, we tested the influence of zinc oxide on aspergillus fumigatus, a. flavus, a. terreus, a. nidu ... | 1996 | 9009659 |
| fine substrate specificities of four exo-type cellulases produced by aspergillus niger, trichoderma reesei, and irpex lacteus on (1-->3), (1-->4)-beta-d-glucans and xyloglucan. | to investigate the fine substrate specificities of four highly purified exo-type cellulases (exo-a from aspergillus niger, cbhi and cbhii from trichoderma reesei, and ex-1 from irpex lacteus), water-soluble substrates such as barley glucan, xyloglucan from tamarind (tamarindus indica l.), and their oligosaccharides were employed. four exo-type cellulases immediately hydrolyzed 3-o-beta-d-cellotriosylglucose to produce cellobiose and laminaribiose. in contrast, cbhii showed no hydrolytic activity ... | 1996 | 9010760 |
| chemical basis of the resistance of barley seeds to pathogenic fungi. | the 5-(n)-alkylresorcinol fraction of the epicuticular waxes of hordeum vulgare seeds appeared to be responsible for their in-born resistance to pathogenic fungi such as aspergillus niger and penicillium crysogenum. the antifungal properties of this fraction were evaluated qualitatively and quantitatively with a novel bioassay where the extreme lipophilicity of these compounds was taken into account. the minimum inhibitory concentration in the fungi tested ranged from 5.6 to 10 micrograms cm-2 f ... | 1997 | 9014369 |
| special transformation processes using fungal spores and immobilized cells. | although many microbial processes have been described which are able to produce interesting aroma compounds, the number of industrial applications are limited. reasons for this are in most cases low final product yield, low biotransformation rates, substrates and/or end-products inhibition, toxicity towards the microorganisms themselves and difficulties of recovery from the bioreaction mixture. this means that the development of specific catalysts and processes is an important challenge for rese ... | 1997 | 9017927 |
| flourishing otomycosis. | | 1997 | 9018926 |
| isolation and characterisation of a gene encoding protein disulphide isomerase, pdia, from aspergillus niger. | current strategies to improve the secretion of heterologous proteins from aspergillus niger include the manipulation of chaperones and foldases specific to the endoplasmic reticulum (er). here we report the isolation of a gene, pdia, encoding a putative protein disulphide isomerase (pdi) from a. niger using the saccharomyces cerevisiae pdi gene as a probe. sequencing of a genomic clone and rt-pcr products predict a 515-aa protein comprising a 20-aa er-translocation signal sequence and a 495-aa m ... | 1997 | 9021130 |
| in situ hybridization for aspergillus and penicillium in allergic fungal sinusitis: a rapid means of speciating fungal pathogens in tissues. | allergic fungal sinusitis (afs) is a serious form of sinonasal fungal disease that is commonly associated with aspergillus or dematiaceous fungi. this study was performed to determine the incidence of aspergillus or penicillium in afs by using in situ hybridization (ish) for aspergillus and penicillium ribosomal rna (rrna). the fontana-masson melanin stain (fmms) was also used to detect pigmented fungi (a. niger and dematiaceous fungi). ish was performed on 26 patients: 17 afs cases with histolo ... | 1997 | 9023249 |
| glucoamylase gene fusions alleviate limitations for protein production in aspergillus awamori at the transcriptional and (post) translational levels. | in this study we have analyzed the effects of a glucoamylase gene fusion on the mrna levels and protein levels for the human interleukin-6 gene (hil6) and the guar alpha-galactosidase gene (agla). previously it was shown that production of nonfused alpha-galactosidase and hil-6 in aspergillus awamori was limited at transcriptional and (post)translational levels, respectively (r. j. gouka, p. j. punt, j. g. m. hessing, and c. a. m. j. j. van den hondel, appl. environ. microbiol. 62:1951-1957, 199 ... | 1997 | 9023927 |
| the phytase subfamily of histidine acid phosphatases: isolation of genes for two novel phytases from the fungi aspergillus terreus and myceliophthora thermophila. | phytases catalyse the hydrolysis of phytate (myo-inositol hexakisphosphate) to myo-inositol and inorganic phosphate. in this study genes encoding novel phytases from two different filamentous fungi, aspergillus terreus strain 9a-1 and myceliophthora thermophila were isolated. the encoded phya phytase proteins show 60% (a. terreus) and 48% (m. thermophila) identity, respectively, to the phya of aspergillus niger and have 21-29% identity compared to other histidine acid phosphatases. all three phy ... | 1997 | 9025298 |
| development of murine monoclonal antibodies for the immunohistochemical diagnosis of systemic bovine aspergillosis. | murine monoclonal antibodies (mabs) against water-soluble somatic antigens (wssa) and the wall fraction (wf) from aspergillus fumigatus were produced by fusion of splenocytes from immunized balb/c mice with mouse myeloma x63-ag 8.653 cells. the supernatants of in vitro cultured hybridomas were initially screened for reactivity with the wssa and the wf from a. fumigatus and wssa of other fungi in an enzyme-linked immunosorbent assay (elisa). supernatants reacting only with a. fumigatus antigens w ... | 1996 | 9026084 |
| the fungus gibberella fujikuroi produces copper/topaquinone-containing amine oxidase when induced by n-butylamine. | crude extract of gibberella fujikuroi aku 3802 mycelium induced with n-butylamine showed a single amine oxidase activity band in a non-denaturing gel that cross-reacted with the antibody against copper/topaquinone-containing amine oxidase from aspergillus niger. the enzyme was purified by a procedure involving four chromatographic steps. purified enzyme was pink with an absorption maximum at 490 nm. molecular mass of 135 kda estimated by gel chromatography and 70 kda found by sds-page confirmed ... | 1997 | 9043630 |
| glucoamylase mutants in the conserved active-site segment trp170-tyr175 located at a distance from the site of catalysis. | to mimic the structure of the 1.8-fold more active (k(cat)) rhizopus oryzae glucoamylase (ga), aspergillus niger ga was subjected to site-directed mutagenesis in the trp170-tyr175 segment of the third of the six well-conserved alpha-->alpha connecting loops of the catalytic (alpha/alpha)6-barrel. while the trp170-->phe, gln172-->asn and tyr175-->phe mutants showed an up to 1.7-fold increased k(cat) and gly174-->cys ga and approximately 2-fold reduced k(cat) towards maltotriose and longer substra ... | 1997 | 9051738 |
| effects of protein glycosylation on catalysis: changes in hydrogen tunneling and enthalpy of activation in the glucose oxidase reaction. | three glycoforms of glucose oxidase, which vary in their degree of glycosylation and resulting molecular weight, have been characterized with regard to catalytic properties. focusing on 2-deoxyglucose to probe the chemical step, we have now measured the temperature dependence of competitive h/t and d/t kinetic isotope effects and the enthalpy of activation using [1-2h]-2-deoxyglucose. the d/t isotope effect on the arrhenius preexponential factor (ad/at) is 1.47 (+/-0.09), 1.30 (+/-0.10), and 0.8 ... | 1997 | 9054567 |
| overexpression and characterization of aspergillus awamori wild-type and mutant glucoamylase secreted by the methylotrophic yeast pichia pastoris: comparison with wild-type recombinant glucoamylase produced using saccharomyces cerevisiae and aspergillus niger as hosts. | glucoamylase from aspergillus niger (identical to aspergillus awamori glucoamylase) is an industrially important, multidomain n- and o-glycosylated starch-hydrolase. to produce protein-engineered glucoamylase, heterologous expression is established in the methylotrophic yeast pichia pastoris. using the vector phil-d2, the cdna encoding a. awamori glucoamylase is inserted in the yeast genome downstream of the 5' aox1 promoter to replace the aox1 gene. induction by 0.75% methanol for 48 h led to s ... | 1997 | 9056481 |
| the specificity of peptide bond cleavage of acid proteinase a from aspergillus niger var. macrosporus toward oxidized ribonuclease a. | in order to investigate the specificity of peptide bond cleavage by acid proteinase a from aspergillus niger var. macrosporus (aspergillopepsin ii), performic acid-oxidized bovine pancreatic ribonuclease a was digested by the enzyme at ph 1.8 or 5.5, and the resulting peptides were separated by hplc and analyzed. among the total 123 peptide bonds approximately thirty and thirteen bonds were cleaved at ph 1.8 for 2 h and at ph 5.5 for 20 h, respectively. cleavages occurred fairly specifically at ... | 1997 | 9058983 |
| cloning and characterization of a cdna encoding a maize seedling phytase. | during germination, maize seedlings express a phytase able to hydrolyse the large amount of phytin stored in the dry seed. previous studies allowed purification and characterization of this enzyme as a homodimer of 38 kda subunits [laboure, gagnon and lescure, biochem. j. (1993) 295, 413-419]. in the present work, an antibody against the purified maize phytase has been used to screen a maize seedling cdna expression library. several positive clones containing an insert of about 1400 bp were isol ... | 1997 | 9065771 |
| survival of selected bacteria and fungi in hypertonic (7.2%) saline. | | 1997 | 9066973 |
| novel antifungal agents which inhibit lanosterol 14alpha-demethylase in candida albicans cch442. | we have identified four non-azole inhibitors of lanosterol 14a-demethylase in candida albicans cch442. the most potent compound, a-39806, had ic50 values for ergosterol inhibition of 0.9 microm (0.3 mg/l) and 1.9 microm (0.6 mg/l) in whole cell and cell-free extract assays, respectively. a-39806 demonstrated broad in-vitro antifungal activity against several candida species as well as against cryptococcus albidus and aspergillus niger. in-vitro antifungal activity was also demonstrated against a ... | 1997 | 9069550 |
| subsite structure of the beta-glucosidase from aspergillus niger, evaluated by steady-state kinetics with cello-oligosaccharides as substrates. | the beta-glucosidase from a commercially available preparation from aspergillus niger was highly purified. the michaelis constant km and the molar activity k0 for cello-oligosaccharide substrates gn (n = 2-6) were obtained by steady-state kinetic analysis on the beta-glucosidase-catalyzed hydrolysis at 25 degrees c and ph 5.0. stoichiometric production of gn-1 by the beta-glucosidase reaction for gn was confirmed by hplc techniques. based on km and k0 for gn, subsite affinities (ai, i = 1-6) wer ... | 1997 | 9076931 |
| effect of water activity, modified atmosphere packaging and storage temperature on spore germination of moulds isolated from prunes. | the combined effect of medium water activity (aw) modified atmosphere packaging (map) on the conidial germination of aspergillus niger, eurotium amstelodami, penicillium chrysogenum and fusarium oxysporum was studied by applying response surface methodology (rsm) for 45 days incubation at 20, 30 and 40 degrees c. oxytetracycline glucose yeast extract (ogye) agar media were prepared over a wide range of aw (0.80-0.95), controlled by glucose. the headspace atmosphere composition varied from 0-20% ... | 1997 | 9081224 |
| secretion of active human mucus proteinase inhibitor by aspergillus niger after kex2-like processing of a glucoamylase-inhibitor fusion protein. | we report the production of human mucus proteinase inhibitor (mpi) by the filamentous fungus aspergillus niger to test the ability of this host organism to secrete low molecular weight, highly disulfide-bonded proteins in biologically active conformation. fungal transformants have been obtained with an expression cassette consisting of a chimeric gene founded on a mpi cdna, encoding mature mpi, fused in frame to sequences encoding a. niger glucoamylase (glaa), separated by a kex2-like processing ... | 1996 | 9084209 |
| enantioselective accumulation of (--)-pinoresinol through o-demethylation of (+/-)-eudesmin by aspergillus niger. | microbial transformation of (+/-)-eudesmin by aspergillus niger was investigated. enantioselective accumulation of (--)-pinoresinol was shown through o-demethylation of (+/-)-eudesmin. this fungus o- demethylated both enantiomers of eudesmin, but the conversion rates for each enantiomer were clearly different. | 1997 | 9094220 |
| identification of essential ionizable groups in active site of aspergillus niger alpha-glucosidase. | a kinetic study was done to identify the ionizable groups in the active site of aspergillus niger alpha-glucosidase (angase). from dependence of v and km values on ph, we obtained the ionization constants of essential ionizable groups 1 and 2 of free enzyme; pke1 = 3.2 and pke2 = 6.4. when the dielectric constant of the reaction mixture was decreased, the pke1 and pke2 were shifted to higher values. the ionization heats (delta h's) of ionizable groups 1 and 2 were measured to be -0.4 kcal/mol an ... | 1997 | 9095552 |
| effect of the copper concentration on citric acid productivity by an aspergillus niger strain. | | 1996 | 9100359 |
| overexpression of phosphofructokinase and pyruvate kinase in citric acid-producing aspergillus niger. | phosphofructokinase and pyruvate kinase were overexpressed in the filamentous fungus aspergillus niger. moderate overexpression of these glycolytic enzymes in a. niger n400 (3-5-fold the wild-type level), either individually or simultaneously, did not increase citric acid production by the fungus significantly. thus, phosphofructokinase and pyruvate kinase do not seem to contribute in a major way to flux control of the metabolism involved in the conversion of glucose to citric acid. overexpressi ... | 1997 | 9101728 |
| chlorine inactivation of fungal spores on cereal grains. | although 0.4% chlorine for 2 min has been recommended for surface disinfection of food samples before direct plating for fungal enumeration, this procedure may not be adequate for highly contaminated products. the effectiveness of a range of chlorine solutions was investigated using barley samples artificially contaminated with four different concentrations of aspergillus flavus. a. niger, a. ochraceus, eurotium repens, penicillium brevicompactum p. chrysogenum and cladosporium cladosporioides. ... | 1997 | 9105923 |
| supplemental phytases of microbial and cereal sources improve dietary phytate phosphorus utilization by pigs from weaning through finishing. | this experiment was conducted to measure the nutritional and metabolic responses of pigs fed diets with continuous supplementation of microbial and cereal phytase from weaning to finishing, and to determine the feasibility of complete replacement of inorganic p addition by supplemental phytase in swine diets. forty-eight landrace x hampshire x meishan pigs were divided into four groups. in phase 1 (10 to 50 kg bw), pigs in groups 1, 2, 3, and 4 were fed a low-p, corn-soybean meal basal diet (bd) ... | 1997 | 9110215 |
| inactivation of yeast and filamentous fungi by the lactoperoxidase-hydrogen peroxide-thiocyanate-system. | the antifungal activity of the lactoperoxidase (lpo) system with glucose oxidase (god) as source of hydrogen peroxide was determined in salt solution and in apple juice. the test organisms rhodutorula rubra and saccharomyces cerevisiae were cultivated aerobically in apple juice, mucor rouxii was grown on wort agar adjusted to ph 4.5. aspergillus niger and byssochlamys fulva were kept on malt extract agar. spores of the filamentous fungi were harvested by suspension in salt solution supplemented ... | 1997 | 9113668 |
| selection of biochemical mutants of aspergillus niger with enhanced catalase production. | the production of extracellular catalase in a submerged culture by a number of biochemical mutants has been evaluated. eight of these mutants showed increased extracellular catalase, the level of which ranged widely in individual cases from 44% to over 94% in comparison with the parental strain. studies of the relationship between a criterion of selection and the frequency of mutation showed that the highest frequency of positive mutations (15.8% and 24.2%) was obtained with respect to mutants r ... | 1997 | 9114519 |
| nonaldehyde sterilization of biologic tissue for use in implantable medical devices. | biologic tissue stabilized by dye-mediated photooxidation has found application in implantable devices. the desire to avoid aldehydes in the processing of photooxidized tissues led to the development of a nonaldehyde, iodine based sterilant. the interaction of tissue with iodine was indicated by a change in tissue shrinkage temperature, dependent upon solution and incubation parameters. the amino acid tyrosine also was altered, presumably because of aromatic ring iodination. transmission electro ... | 1997 | 9116349 |
| [uses of microbial beta-galactosidases to reduce lactose content in milk and dairy products]. | the commercial sources of microbial beta-galactosidases (lactases) include the yeasts species kluyveromyces marxianus, kluyveromyces lactis and candida kefyr which are used to hydrolyse lactose in milk due to their optimum ph. on the other hand, lactases obtained from the moulds aspergillus niger and aspergillus oryzae have an acid optimum ph and therefore are used to hydrolyse lactose in whey to obtain whey syrups to be used as raw materials in the food industry. the lactose intolerance problem ... | 1996 | 9122548 |
| production of gibberellic acid by aspergillus niger using some food industry wastes. | the production of gibberellic acid by aspergillus niger and the possibility of utilizing food industry waste and residues as the sources of carbon in media were investigated. media prepared from molasses, vinasse, whey, sugar-beet waste and fruit pomace were used and ga3 yields were found in concentrations 310, 273.14, 120, 73, 118.13 mg/l in such media, respectively. it was observed that food industry wastes can be used as cheap sources of carbon for gibberellic acid production by aspergillus n ... | 1996 | 9127484 |
| beta-xylosidase activity, encoded by xlnd, is essential for complete hydrolysis of xylan by aspergillus niger but not for induction of the xylanolytic enzyme spectrum. | two proteins exhibiting beta-d-xylosidase activity were identified upon fractionation and purification of a culture filtrate of an arabinoxylan-grown aspergillus niger. a single band of 110 kda by sds/page was obtained in both cases and these were active on xylo-oligosaccharides and on xylan. partial xlnd cdna clones were immunochemically identified and isolated from a lambda cdna expression library. sequence analysis showed that all cdna clones correspond to a single gene. a genomic clone was i ... | 1997 | 9128738 |
| the stability of extracellular beta-glucosidase from aspergillus niger is significantly enhanced by non-covalently attached polysaccharides. | the removal of noncovalently bound polysaccharide coating from the extracellular enzymes of aspergillus niger, by the technique of compartmental electrophoresis, had a very dramatic effect on the stability of beta-glucosidase. the polysaccharide-beta-glucosidase complex was extremely resistant to proteinases and far more stable against urea and temperature as compared with polysaccharide-free beta-glucosidase. the beta-glucosidase-polysaccharide complex was 18-, 36-, 40- and 82-fold more stable ... | 1996 | 9131791 |
| purification and properties of two forms of glucoamylase from aspergillus niger. | a. niger produced alpha-glucosidase, alpha-amylase and two forms of glucoamylase when grown in a liquid medium containing raw tapioca starch as the carbon source. the glucoamylases, which formed the dominant components of amylolytic activity manifested by the organism, were purified to homogeneity by ammonium sulfate precipitation, ion-exchange and two cycles of gel filtration chromatography. the purified enzymes, designated ga1 and ga2, a raw starch digesting glucoamylase, were found to have mo ... | 1996 | 9138312 |
| characterization and overexpression of the aspergillus niger gene encoding the camp-dependent protein kinase catalytic subunit. | the gene pkac encoding the catalytic subunit of camp-dependent protein kinase has been isolated from the industrially important filamentous fungus aspergillus niger. a probe for screening a. niger phage libraries was generated by a polymerase chain reaction using degenerate primers. cdna and genomic dna clones were isolated and sequenced. an open reading frame of 1440 bp, interrupted by three short introns, encodes a polypeptide of 480 amino acids with a calculated molecular mass of 53813 da. th ... | 1997 | 9141684 |
| gene cloning, purification, and characterization of a heat-stable phytase from the fungus aspergillus fumigatus. | the finding of heat-stable enzymes or the engineering of moderately thermostable enzymes into more stable ones by random or site-directed mutagenesis has become a main priority of modern biotechnology. we report here for the first time a heat-stable phytase able to withstand temperatures up to 100 degrees c over a period of 20 min, with a loss of only 10% of the initial enzymatic activity. the gene (phya) encoding this heat-stable enzyme has been cloned from aspergillus fumigatus and overexpress ... | 1997 | 9143104 |
| onychomycosis in rome, italy. | this report presents the results of a study conducted between 1985 and 1994 on onychomycosis observed in the city of rome. six thousand six hundred and eighty eight patients were examined during this period. among them 1,762 (26.3%) were affected by fungal nail infections. because the etiologic agents could not be isolated in 105 cases (6%), the results refer to 1,657 subjects (24.8% of the total), presenting with positive microscopic and cultural examinations. thirty eight patients (2.3%) had o ... | 1996 | 9144955 |
| characterization of aspergillus isolates by pyrolysis mass spectrometry. | pyrolysis mass spectrometry (pyms) is a useful typing method for many bacterial and candida species. we attempted to type aspergillus spp. by pyms. four distinct a. fumigatus isolates could not be distinguished from each other, whereas one a. niger and one a. terreus could. poor reproducibility was shown using multiple identical cultures of a single a. fumigatus isolate and several isolates of the same dna type. pyms is obviously an unsuitable typing method for aspergillus spp. | 1996 | 9144999 |
| allergic fungal sinusitis: clinicopathological characteristics. | allergic fungal sinusitis is a comparatively new disease entity in paranasal sinus mycoses. it is not a very rare condition, but diagnosis is difficult to establish. of 28 consecutive cases of allergic nasal polyposis during a 2-year period, 11 patients had allergic fungal sinusitis and the diagnosis was based on the presence of type i hypersensitivity, eosinophilic mucus without tissue invasion of fungi on histopathology and detection of septate hyphae on direct microscopy. on culture, aspergil ... | 1996 | 9145000 |
| biodegradation of wool by trichophyton simii and aspergillus niger. | the amount of protein released into liquid culture medium and weight loss were taken as measures of wool degradation by trichophyton simii and aspergillus niger. protein released into the culture medium was observed to be greater after t. simii treatment than after a. niger treatment. sulphitolysis was shown by t. simii, whereas it was absent in the case of a. niger, ph was found to be alkaline with an increase in soluble protein in the culture medium in the case of both uniculture and dual cult ... | 1996 | 9145010 |
| hydrolysis of xylan by aspergillus niger immobilized on non-woven fabrics. | aspergillus niger, which produces xylan-degrading enzymes, was immobilized on non-woven fabrics. the maximum xylan hydrolysis activity (15 u/cm3-support) and the highest stability were obtained when the fungus was immobilized on non-woven fabric made of silk. the enzymatic properties of the immobilized preparation were similar to those of the free enzyme. ten times repeated batch hydrolysis of birch-wood xylan was done over a period of 450 h. hydrolysis of different xylan substrates such as oat ... | 1997 | 9145514 |
| synthesis by an alpha-glucosidase of glycosyl-trehaloses with an isomaltosyl residue. | glycosyl-trehaloses with an isomaltosyl residue were synthesized by alpha-glucosidase from aspergillus niger by using maltotetraose as a glucosyl donor and trehalose as the acceptor. the one trisaccharide and two tetrasaccharides formed were isolated by successive column chromatography. the results of an enzymatic digestion, methylation analysis, and 13c-nmr studies indicated that these oligosaccharides were alpha-isomaltosyl alpha-glucoside, alpha-isomaltotriosyl alpha-glucoside and alpha-isoma ... | 1997 | 9145529 |
| prevalence of phthioic acid in aspergillus species. | we examined fast atom bombardment mass spectra (fab-ms) of 29 clinical isolates of aspergillus, from five pathogenic species, for the presence of phthioic acid anions (m/z 395.6) when grown at 37 degrees c. phthioic acid was detected in only one of 12 a. fumigatus, three of nine a. terreus and one of four a. niger isolates. phthioic acid is unlikely to be a major pathogenicity determinant of aspergillus. | 1997 | 9147275 |
| two divergent catalase genes are differentially regulated during aspergillus nidulans development and oxidative stress. | catalases are ubiquitous hydrogen peroxide-detoxifying enzymes that are central to the cellular antioxidant response. of two catalase activities detected in the fungus aspergillus nidulans, the cata gene encodes the spore-specific catalase a (cata). here we characterize a second catalase gene, identified after probing a genomic library with cata, and demonstrate that it encodes catalase b. this gene, designated catb, predicts a 721-amino-acid polypeptide (catb) showing 78% identity to an aspergi ... | 1997 | 9150225 |
| positive vitreous cultures from eyes without signs of infectious endophthalmitis. | there is little information on the rate of false-positive vitreous cultures, because cultures from presumably sterile vitreous are not routinely taken in clinical practice. the objective of this study was to determine the rate of positive vitreous cultures from patients who have no signs of endophthalmitis. | 1997 | 9150519 |
| optimization of catalase biosynthesis in submerged cultures of aspergillus niger mutant. | the effect of some medium components, viscous substances and metabolic inhibitors, on catalase production by mutant aspergillus niger has been studied in shake culture. altering the composition of the basal medium, particularly substituting nano3 for kno3, and peptone for yeast extract brought an increase in extra- and intracellular catalase activity by 1.5- and 3-fold, respectively. the addition of 2.0-6.0 mg sodium alginate or pectin/ml as viscous additive to the medium, containing glucose as ... | 1997 | 9151421 |
| soaking increases the efficacy of supplemental microbial phytase in a low-phosphorus corn-soybean meal diet for growing pigs. | sixty-three crossbred barrows averaging 18.7 kg initial bw were used in a 6-wk study of the effects of soaking on the efficacy of supplemental microbial phytase (natuphos, basf) in a low-p corn-soybean meal diet. the basal corn-soybean meal diet contained .06% available p, .32% total p, and .55% ca with no added inorganic p. the basal diet was supplemented with 0, 250, or 500 phytase units (pu)/kg of diet. the diet was fed dry or soaked (2 parts water:1 part diet and mixed for 2 h at 30 degrees ... | 1997 | 9159276 |
| arabinanase a from pseudomonas fluorescens subsp. cellulosa exhibits both an endo- and an exo- mode of action. | pseudomonas fluorescens subsp. cellulosa expressed arabinanase activity when grown on media supplemented with arabinan or arabinose. arabinanase activity was not induced by the inclusion of other plant structural polysaccharides, and was repressed by the addition of glucose. the majority of the pseudomonas arabinanase activity was extracellular. screening of a genomic library of p. fluorescens subsp. cellulosa dna constructed in lambda zapii, for recombinants that hydrolysed red-dyed arabinan, i ... | 1997 | 9163351 |
| factors affecting the spread of double-stranded rna viruses in aspergillus nidulans. | viruses are common in asexual aspergilli but not in sexual aspergilli. we found no viruses in 112 isolates of the sexual aspergillus nidulans. we have investigated factors that could play a role in preventing the spread of mycoviruses through populations of a. nidulans. experiments were performed with a. nidulans strains infected with viruses originating from a. niger. horizontal virus transmission was restricted but not prevented by somatic incompatibility. viruses were transmitted vertically v ... | 1997 | 9164170 |
| production of aspergillus niger pectolytic enzymes by solid state bioprocessing of apple pomace. | the aim of this work was to develop a low cost process for apple pomace utilisation. accordingly this production of pectynolitic enzymes based on solid state bioprocessing of this actual waste, was developed. production of pectolytic enzymes of aspergillus niger, pectinesterase and polygalacturonase as well as the activity of pectolytic enzymatic complex by solid state bioprocessing were studied. the results of preliminary substrate optimization, on open trays in laboratory scale experiments, we ... | 1997 | 9165759 |
| cloning and sequencing of an alpha-glucosidase gene from aspergillus niger and its expression in a. nidulans. | we have cloned an extracellular alpha-glucosidase gene from aspergillus niger with oligonucleotide probes synthesized on the basis of the determined peptide sequences. the nucleotide sequence revealed an open reading frame of 985 amino acids split with three introns, and the deduced amino acid sequence was nearly identical to that of the alpha-glucosidase previously determined. the cloned gene was introduced into aspergillus nidulans, and its expression in the transformants was shown to be regul ... | 1997 | 9165762 |
| cloning of a protopectinase gene of trichosporon penicillatum and its expression in saccharomyces cerevisiae. | a protopectinase (ppase)-encoding gene, pse3, from trichosporon penicillatum was cloned by colony hybridization using two oligonucleotide probes synthesized from the n-terminal amino acid sequences of native ppase se1 and one peptide from a lysyl endopeptidase digest. nucleotide sequencing revealed that pse3 contains an orf encoding a 367 amino acid protein. mature ppase se3 is composed of 340 amino acids and the n-terminus of the orf appeared to correspond to a signal peptide and a propeptide p ... | 1997 | 9168614 |
| molecular cloning and heterologous expression of the isopullulanase gene from aspergillus niger a.t.c.c. 9642. | isopullulanase (ipu) from aspergillus niger a.t.c.c. (american type culture collection) 9642 hydrolyses pullulan to isopanose. ipu is important for the production of isopanose and is used in the structural analysis of oligosaccharides with alpha-1,4 and alpha-1,6 glucosidic linkages. we have isolated the ipua gene encoding ipu from the filamentous fungi a. niger a.t.c.c. 9642. the ipua gene encodes an open reading frame of 1695 bp (564 amino acids). ipu contained a signal sequence of 19 amino ac ... | 1997 | 9169610 |
| a classification of dextran-hydrolysing enzymes based on amino-acid-sequence similarities. | | 1997 | 9169623 |
| selective isolation of aspergillus niger mutants with enhanced glucose oxidase production. | after mutagenization and selection, mutant aspergillus niger strains resistant to certain agents were obtained. seven of the mutants showed increased extracellular glucose oxidase (god), the level for individual cases ranged widely from 8.8 to over 138.5% in comparison with the parental strain. studies of the relationship between method of selection and frequency of mutation showed that the highest frequency of positive mutations (15.8% and 17.3%) was obtained from mutants resistant to ethidium ... | 1997 | 9172408 |
| all-aqueous, regiospecific transglycosylation synthesis of 3-o-alpha-l-fucopyranosyl-2-acetamido-2-deoxy-d-glucopyranose, a building block for the synthesis of branched oligosaccharides. | a transglycosylation reaction, carried out in an aqueous medium and catalyzed by a crude preparation of alpha-fucosidase (e.c. 3.2.1.51) from aspergillus niger, allowed for the regiospecific synthesis of the disaccharide 3-o-alpha-l-fucopyranosyl-2-acetamido-2-deoxy-d-glucopyranose using p-nitrophenyl-alpha-l-fucopyranose as the donor and 2-acetamido-2-deoxy-d-glucopyranose as the acceptor. the chemical identity of the product obtained was demonstrated by hplc, ion spray mass spectrometry and nm ... | 1997 | 9177275 |
| a simplified procedure for a rapid and reliable assay of both glycogen and trehalose in whole yeast cells. | | 1997 | 9177741 |
| recombination of mitochondrial dnas following transmission of mitochondria among incompatible strains of black aspergilli. | successful intra- and interspecific mitochondrial transfers were performed by polyethylene glycol (peg)-induced protoplast fusion among incompatible strains belonging to the aspergillus niger species aggregate. the mitochondrial dnas (mtdnas) of the strains examined were of three main types based on their restriction fragment length polymorphism (rflp) profiles. mtdna types 1 and 2 correspond to a. niger and a. tubingensis species, respectively, while type 3 is represented by some brazilian wild ... | 1997 | 9180691 |
| molecular cloning and nucleotide sequence of an endo-1,5-alpha-l-arabinase gene from bacillus subtilis. | the nucleotide sequence of the gene encoding an endo-1,5-alpha-l-arabinase (protopectinase c) of bacillus subtilis was determined by sequencing fragments amplified by the cassette-ligation-mediated pcr (clm-pcr). the gene covering the start and stop codon was amplified by pcr with two specific primers, which were designed from the sequence data determined by clm-pcr. an approximately 1.5-kb amplification product was cloned into the vector puc119, forming a plasmid termed pppc. an orf that encode ... | 1997 | 9183009 |
| construction of a brewing yeast having glucoamylase activity and its fermentation characteristics. | the brewing yeast having glucoamylase activity was constructed by integrating glucoamylase cdna from asapergillus niger into the genome of brewing yeast b48. the integration was achieved by cotransformation of yep type plasmid pkg1 carrying glucoamylase expression-secretion element and was verified by southern blot analysis. the engineered yeast was stable, and the fermentation test demonstrated that the lower residual dextrin level was obtained compared with control strain b48. thus the ferment ... | 1996 | 9187499 |
| solution structure of the granular starch binding domain of aspergillus niger glucoamylase bound to beta-cyclodextrin. | carbohydrate-binding domains are usually small and physically separate from the catalytic domains of hydrolytic enzymes. glucoamylase 1 (g1) from aspergillus niger, an enzyme used widely in the food and brewing industries, contains a granular starch binding domain (sbd) which is separated from the catalytic domain by a semi-rigid linker. the aim of this study was to determine how the sbd binds to starch, and thereby more generally to throw light on the role of carbohydrate-binding domains in the ... | 1997 | 9195884 |
| two crystal structures of pectin lyase a from aspergillus reveal a ph driven conformational change and striking divergence in the substrate-binding clefts of pectin and pectate lyases. | microbial pectin and pectate lyases are virulence factors that degrade the pectic components of the plant cell wall. the homogalacturan backbone of pectin varies in its degree of methylation from the highly methylated and relatively hydrophobic form known as pectin, to the fully demethylated and highly charged form known as pectate. methylated and demethylated regions of pectin are cleaved by pectin lyase and calcium-dependent pectate lyases, respectively. protein engineering of lyases specific ... | 1997 | 9195887 |
| the acetate regulatory gene facb of aspergillus nidulans encodes a zn(ii)2cys6 transcriptional activator. | genetic studies have indicated that the facb gene of aspergillus nidulans is a major regulatory gene involved in acetamide and acetate utilisation. sequencing of the facb gene revealed that it encodes a protein that contains an n-terminal gal4-like zn(ii)2cys6 (or c6 zinc) binuclear cluster for dna binding, leucine zipper-like heptad repeat motifs and central and c-terminal acidic alpha-helical regions, consistent with a function as a dna-binding transcriptional activator. the zn(ii)2cys6 cluste ... | 1997 | 9197408 |
| function of conserved tryptophans in the aspergillus niger glucoamylase 1 starch binding domain. | nuclear magnetic resonance (nmr) and ultraviolet (uv) difference spectroscopy were used to assess the role of a number of tryptophan residues in the granular starch binding domain (sbd) of glucoamylase 1 from aspergillus niger. wild-type sbd and three variant (w563k, w590k, and w615k) proteins were produced using an a. niger expression system. titration studies were conducted with beta-cyclodextrin (betacd), a cyclic analogue of starch, as the ligand. the nmr studies show that the w563k and w590 ... | 1997 | 9200704 |
| investigation of pulsed light for terminal sterilization of wfi filled blow/fill/seal polyethylene containers. | a study was performed to assess the ability of pulsed light to sterilize water for injection in blow/fill/seal polyethylene containers. pulsed light uses intense, short duration flashes of broad spectrum white light to produce high levels of microbial kill. in a first phase of testing, containers of 0.5, 5, 15, and 120 ml nominal volume were inoculated with bacillus pumilus endospores, bacillus subtilus variety niger strain globigii endospores, bacillus stearothermophilus endospores, and aspergi ... | 1997 | 9203823 |
| synthesis of isopropyl-1-thio-beta-d-glucopyranoside (iptglc), an inducer of aspergillus niger b1 beta-glucosidase production. | production of beta-glucosidase in aspergillus niger b1 is subjected to catabolic repression by glucose. aspergillus niger b1 grown on bran as a carbon source secreted beta-glucosidase. the maximum level of the enzyme was reached after 7 d of fermentation. addition of 1% glucose to the medium suppressed beta-glucosidase production to undetectable levels. in this study, the organic synthesis of a potential inducer of beta-glucosidase production by a. niger b1's reported. isopropyl-1-thio-beta-d-gl ... | 1997 | 9204516 |
| chemical and biological characterization of two fk506 analogs produced by targeted gene disruption in streptomyces sp. ma6548. | two genetically engineered mutant strains of streptomyces sp. ma6548 produced two fk506 analogs, 9-deoxo-31-o-demethylfk506 and 31-o-demethylfk506. the structures were determined by a combination of nmr and mass spectrometry. these compounds exhibited immunosuppressive and antifungal activities, albeit reduced, compared to fk506. both compounds contain a free hydroxyl group at c-31 for the synthesis of novel fk506 derivatives. | 1997 | 9207912 |
| fungi associated with post-harvest rot of black plum (vitex doniana) in nigeria. | the fungi associated with rot of vitex doniana fruits (blackplum) were isolated and identified. aspergillus niger, botryodiplodia theobromae, candida spp. penicillium chrysogenum, rhizopus stolonifer, fusarium pallidoroseum f. oxysporum and mucor mucedo were the primary rot causing fungi in contrast to cladosporium herbarum and mucor circinelloides which were just present as secondary colonizers. the rot fungi penetrated mainly through wounds and bruises on the surface of fruits. mature green fr ... | 1996 | 9208478 |
| fungi associated with herbal drug plants during storage. | samples of sundried herbal drug plant parts stored for sale were purchased from four herbal markets located in ibadan, nigeria. the plant parts were analysed for mycoflora associated with their storage. fungal colony counts ranged from 0.60 x 10(2) to 3.50 x 10(2) within the period of the survey. twenty eight fungal species were isolated with the species of aspergillus niger, a. flavus, fusarium moniliforme, trichoderma viride, penicillium expansum and mucor fragilis being the dominant ones. the ... | 1996 | 9208479 |
| structural and biochemical properties of glycosylated and deglycosylated glucose oxidase from penicillium amagasakiense. | glucose oxidase from penicillium amagasakiense was purified to homogeneity by ion-exchange chromatography and deglycosylated with endoglycosidase h. on the basis of gas chromatography and sodium dodecyl sulphate/polyacrylamide gel electrophoretic (sds-page) analyses, the protein-bound high-mannose-type carbohydrate moiety corresponded to 13% of the molecular mass of glycosylated glucose oxidase. a total of six n-glycosylation sites per dimer were determined from the n-acetylglucosamine content. ... | 1997 | 9210339 |
| cloning and characterization of two rhamnogalacturonan hydrolase genes from aspergillus niger. | a rhamnogalacturonan hydrolase gene of aspergillus aculeatus was used as a probe for the cloning of two rhamnogalacturonan hydrolase genes of aspergillus niger. the corresponding proteins, rhamnogalacturonan hydrolases a and b, are 78 and 72% identical, respectively, with the a. aculeatus enzyme. in a. niger cultures which were shifted from growth on sucrose to growth on apple pectin as a carbon source, the expression of the rhamnogalacturonan hydrolase a gene (rhga) was transiently induced afte ... | 1997 | 9212401 |
| a spontaneous change in the intracellular cyclic amp level in aspergillus niger is influenced by the sucrose concentration in the medium and by light. | a spontaneous rise in intracellular cyclic amp (camp) levels was observed in the early stages of aspergillus niger growth under conditions yielding large amounts of citric acid. the amount of camp formed was found to depend on the initial concentration of sucrose in the medium. under higher-sucrose conditions, the camp peak appeared earlier and was higher, while in lower-sucrose media a flattened peak was observed later in fermentation. since in media with higher concentrations of sucrose intrac ... | 1997 | 9212431 |
| novel metabolites in phenanthrene and pyrene transformation by aspergillus niger. | aspergillus niger, isolated from hydrocarbon-contaminated soil, was examined for its potential to degrade phenanthrene and pyrene. two novel metabolites, 1-methoxyphenanthrene and 1-methoxypyrene, were identified by conventional chemical techniques. minor metabolites identified were 1- and 2-phenanthrol and 1-pyrenol. no 14co2 evolution was observed in either [14c]phenanthrene or [14c]pyrene cultures. | 1997 | 9212437 |
| purification and characterization of a glucose-tolerant beta-glucosidase from aspergillus niger ccrc 31494. | an extracellular glucose-tolerant beta-glucosidase was purified to homogeneity by alcohol fractionation and preparative isoelectric focusing from aspergillus niger ccrc 31494. the enzyme was a dimeric protein with a subunit of 49,000, and had its optimum activity at ph 5.0 and 55 degrees c. the enzyme was completely inhibited by 5 mm ag+. thiol groups and serine residues were not essential for its activity. low concentrations of alcohols (10%) except for methanol could activate the enzyme. it wa ... | 1997 | 9214755 |