| incidence and significance of aspergillus cultures following liver and kidney transplantation. | aspergillus infection is a rare but devastating complication following solid organ transplantation, with mortality rates that approach 100%. aspergillus species (sp) are also ubiquitous in our environment and may contaminate culture plates. to determine the significance of positive aspergillus cultures, we analyzed all positive cultures from the liver and kidney transplant services at our center for the treatments used and clinical outcomes. aspergillus sp. were cultured from 4.5% of liver and 2 ... | 1996 | 8610402 |
| two distinct quinoprotein amine oxidases are induced by n-butylamine in the mycelia of aspergillus niger aku 3302. purification, characterization, cdna cloning and sequencing. | two distinct quinoprotein amine oxidases were found in aspergillus niger mycelia grown on n-butylamine medium and purified using chromatographic techniques. the respective enzymes were termed ao-i, which had already been isolated, and ao-ii, a new enzyme found in this study. hplc indicated that their molecular masses are 150 kda and 80 kda, respectively. on sds/page, the enzymes gave a similar but distinct mobility, which corresponds to 75 kda for the subunit dimeric ao-i and 80 kda for monomeri ... | 1996 | 8620882 |
| identification and cloning of a mobile transposon from aspergillus niger var. awamori. | aspergillus niger var. awamori contains multiple copies of a transposable element, vader. this element was detected as a 437-bp insertion in four independently isolated spontaneous mutants of the niad (nitrate reductase) gene. the vader element is present in approximately 15 copies in both a. niger var. awamori and a. niger. a single copy of vader was detected from only one of the two laboratory strains of a. nidulans which were also examined. insertion of the vader element into the niad gene of ... | 1996 | 8625427 |
| expression of an erwinia pectate lyase in three species of aspergillus. | transgenic filamentous fungi of the species aspergillus niger, a. nidulans and a. awamori expressing and secreting erwinia carotovora subsp. atroseptica pectate lyase 3 (pl3) were generated. correct processing of the pre-enzyme was achieved using the a. niger pectin lyase a (pel a) signal peptide. with the prepro-peptide of a. niger polygalacturonase ii, secreted enzymes still possessed the 6- aa pro-sequence, indicating the importance of the conformation of the precursor protein for correct cle ... | 1996 | 8625428 |
| isolation and molecular characterisation of the gene encoding eburicol 14 alpha-demethylase (cyp51) from penicillium italicum. | the cyp51 gene encoding eburicol 14 alpha-demethylase (p450(14dm)) was cloned from a genomic library of the filamentous fungal plant pathogen penicillium italicum, by heterologous hybridisation with the corresponding gene encoding lanosterol 14 alpha-demethylase from the yeast candida tropicalis. the nucleotide sequence of a 1739-bp genomic fragment and the corresponding cdna clone comprises an open reading frame (orf) of 1545 bp, encoding a protein of 515 amino acids with a predicted molecular ... | 1996 | 8628233 |
| dietary aspergillus niger phytase increases iron absorption in humans. | phytate is an inhibitor of iron absorption that can be removed before the intestinal site of absorption by microbial phytase, thereby increasing iron absorption from a meal. the effects of two kinds of dietary phytase, cereal phytase and microbial phytase from aspergillus niger, on iron absorption were investigated. iron absorption was measured from single meals containing white wheat rolls supplemented with wheat bran with or without phytase activity (expt. 1) and phytase-deactivated wheat bran ... | 1996 | 8632221 |
| catalytic mechanism of glucoamylase probed by mutagenesis in conjunction with hydrolysis of alpha-d-glucopyranosyl fluoride and maltooligosaccharides. | the catalytic mechanism of glucoamylase (ga) is investigated by comparing kinetic results obtained using alpha-d-glucosyl fluoride (gf) and maltooligosaccharides as substrates for wild-type and four active site mutant gas, tyr116-->ala, trp120-->phe, asp176-->asn, and glu400-->gln. these replacements decreased the activity (kcat/km) toward maltose by 6-320-fold. toward gf, however, tyr116-->ala and trp120-->phe gas, showed wild-type and twice wild-type level activity, while asp176-->asn and glu4 ... | 1996 | 8639668 |
| heterologous expression and site-directed mutagenesis studies on the activation mechanism and the roles of the basic residues in the prosegment of aspergillopepsinogen i. | to study the structure/function relationship of the prosegment of aspartic proteinase, a putative proform of aspergillopepsin i (or proteinase b) from aspergillus niger var. macrosporus was expressed by escherichia coli, refolded in vitro, and purified. the conversion of the purified proenzyme (aspergillopepsinogen i, proproteinase b) into the active mature form occurred at ph < or = 4.5 and was completely inhibited by pepstatin a, a specific inhibitor for aspartic proteinase, suggesting autopro ... | 1996 | 8647118 |
| the use of differential measurements with a glucose biosensor for interference compensation during glucose determinations by flow injection analysis. | a novel detection system for the determination of glucose in the presence of clinically important interferents, based on the use of dual sensors and flow-injection analysis (fia), is described. the normalisation methodology involves measurement of the interference signal at a reference sensor; this signal can then be subtracted from the glucose sensor signal (post-run) to give a corrected measurement of the glucose concentration. the detection system consists of a thin layer with dual glassy car ... | 1995 | 8652108 |
| initial oxidative and subsequent conjugative metabolites produced during the metabolism of phenanthrene by fungi. | three filamentous fungi were examined for the ability to biotransform phenanthrene to oxidative (phase i) and conjugative (phase ii) metabolites. phenanthrene metabolites were purified by high-performance liquid chromatography (hplc) and identified by uv/visible absorption, mass, and 1h nmr spectra. aspergillus niger atcc 6275, syncephalastrum racemosum ut-70, and cunninghamella elegans atcc 9245 initially transformed [9-(14)c]phenanthrene to produce metabolites at the 9,10-, 1,2-, and 3,4-posit ... | 1996 | 8652115 |
| influence of the carbohydrate moiety on the stability of glycoproteins. | to study the role of oligosaccharides on the properties of glycoproteins, five glycoproteins (yeast external invertase, bovine serum fetuin, glucoamylase from aspergillus niger, and chicken egg white ovotransferrin and avidin) of previously established glycan patterns were purified to homogeneity and deglycosylated with endo- and exo-glycosidases in native conditions. thermal stability and conformational changes were measured by high-resolution differential scanning microcalorimetry and circular ... | 1996 | 8652506 |
| [cyclosporin a and the permeability of the cytoplasmic membrane in aspergillus niger]. | cyclosporine a was shown to impair selective permeability of cytoplasmic membranes in aspergillus niger thus inducing leakage of low molecular components of the intracellular fond from the cells. in this respect lyposomal cyclosporine had a more pronounced action than the free form. cyclosporine was compared with amphotericin b and the latter in the free and lyposomal forms demonstrated a higher effect on the cell membranes of asp. niger. in combination with amphotericin b cyclosporine markedly ... | 1995 | 8660115 |
| selection of multiple disruption events in aspergillus fumigatus using the orotidine-5'-decarboxylase gene, pyrg, as a unique transformation marker. | a 8.6-kb disruption cassette, referred to here as a pyrg-blaster and consisting of the aspergillus niger pyrg gene flanked by a direct repeat that encodes the neomycin phosphotransferase of transposon tn5 was constructed. following transformation of a uridine/uracil auxotrophic pyrg strain of a. fumigatus, genomic insertions of the pyrg-blaster were obtained either by targeted gene replacement at the roda locus, resulting in the formation of hydrophilic spores, or by ectopic integration. in both ... | 1996 | 8662213 |
| isolation and characterization of the versicolorin b synthase gene from aspergillus parasiticus. expansion of the aflatoxin b1 biosynthetic gene cluster. | versicolorin b synthase catalyzes the side chain cyclization of racemic versiconal hemiacetal to the bisfuran ring system of(-)-versicolorin b, an essential transformation in the aflatoxin biosynthetic pathway of aspergillus parasiticus. the dihydrobisfuran is key to the mutagenic nature of aflatoxin b1. the protein, which shows 58% similarity and 38% identity with glucose oxidase from aspergillus niger, possesses an amino-terminal sequence homologous to the adp-binding region of other flavoenzy ... | 1996 | 8662689 |
| trehalose-6-phosphate synthase a affects citrate accumulation by aspergillus niger under conditions of high glycolytic flux. | accumulation of citric acid by aspergillus niger depends on a high flux through glycolysis. we have investigated the possibility of control of this flux by trehalose 6-phosphate, an inhibitor of hexokinase of saccharomyces cerevisiae and other eukaryotes (blasquez et al., febs lett. (1993) 329, 51-54). hexokinase of a. niger was shown in vitro to be only weakly inhibited by trehalose 6-phosphate (ki 1.5-2 mm). to investigate the in vivo relevance of this inhibition, we used isogenic strains of a ... | 1996 | 8666204 |
| production, characterization and application of the cellulase-free xylanase from aspergillus niger. | the effects of carbon source on xylanase and cellulase production were studied. the extract of steam-exploded corn stover was found to be the best raw material for producing cellulase-free xylanase. the xylanolytic enzymes of aspergillus niger an-76 were purified by chromatography, and the properties of the four purified components were analyzed. when the enzyme was used to treat the birch kraft pulp, and followed by a subsequent ceh bleaching, a brightness of 6.8% sbd more than that of the untr ... | 1996 | 8669904 |
| efficient production from aspergillus niger of a heterologous protein and an individual protein domain, heavy isotope-labelled, for structure-function analysis. | aspergillus niger has been used successfully to secrete proteins labelled with 13c and/or 15n to a specific activity of > 99% for high resolution nmr analysis. in the case of a heterologous protein, hen egg-white lysozyme, 15n single-labelled and 13c, 15n double-labelled forms were secreted at yields of 100-200 mg l-1 by optimising the type of carbon source used and the ratio of carbon to nitrogen. another protein, the glucoamylase starch-binding domain from a. niger, was also produced as the 15 ... | 1996 | 8672288 |
| do not drink mate. an additional source of infection in south american neutropenic patients. | | 1996 | 8673047 |
| organic acid production by aspergillus niger in recycling culture analyzed by capillary electrophoresis. | wild-type aspergillus niger n402 and glucoamylase++ overproducing transformant a. niger n402[pab6-10]b1 have grown in maltodextrin- and xylose-limited recycling culture at ph 4.5 on mineral medium. the only products formed were organic acids and proteins, among which glucoamylase. the production of organic acids by the fungus has been analyzed qualitatively and quantitatively using capillary electrophoresis. the only organic acids produced in these cultures were substantial amounts of citric aci ... | 1995 | 8678298 |
| effect of phytic acid and microbial phytase on cd accumulation, zn status, and apparent absorption of ca, p, mg, fe, zn, cu, and mn in growing rats. | three groups of individually housed albino rats (n = 6, initial average weight = 47 g) were fed diets based on egg white and cornstarch (basal diet 8 g ca, 5.2 g p, 0.76 g mg, 100 mg zn, 100 mg fe, 50 mg mn, 7 mg cu, and 5 mg cd per kilogram diet) over a 4-week period. group i (controls) was fed the basal diet free of phytic acid (pa) and microbial phytase. in groups ii and iii cornstarch was replaced by 0.5% pa from napa (molar pa/zn ratio approximately 5). in group iii, 2,000 u of microbial ph ... | 1995 | 8678472 |
| purification and characterization of a novel esterase induced by growth of aspergillus niger on sugar-beet pulp. | an inducible esterase has been isolated from a liquid culture of aspergillus niger grown on sugar-beet pulp. the enzyme was active on methyl esters of cinnamic acids, caffeic > p-coumaric > ferulic, and is therefore termed a cinnamoyl esterase. the enzyme was not active on methyl sinapinate, a good substrate for ferulic acid esterase iii, which was purified previously from a. niger [faulds and williamson (1994) microbiology 140, 779-787]. with methyl caffeate as substrate the enzyme had temperat ... | 1996 | 8679110 |
| release of ferulic acid from sugar-beet pulp by using arabinanase, arabinofuranosidase and an esterase from aspergillus niger. | aspergillus niger cinnamoyl esterase (cinnae) is shown to be active towards a wide range of feruloylated oligosaccharides derived from sugar-beet pulp (sbp). the esterase hydrolysed ferulic acid ester-linked to either c-2 of arabinose or c-6 of galactose residues, and demonstrated the highest activity towards the feruloylated arabinose trisaccharide. however, cinnae was able to release only 0.88% of total alkali-extractable ferulic acid from sbp in 24 h when acting alone. to determine whether ce ... | 1996 | 8679111 |
| two amine oxidases from aspergillus niger aku 3302 contain topa quinone as the cofactor: unusual cofactor link to the glutamyl residue occurs only at one of the enzymes. | amine oxidases (ec 1.4.3.6) from aspergillus niger, ao-i (2 x 75 kda) and ao-ii (80 kda), were examined to determine the cofactor structure. inactivated with p-nitrophenylhydrazine, they showed absorption and fluorescence spectra similar to those published for other copper amine oxidases and to topa hydantoin p-nitrophenylhydrazone. after digestion by thermolysin and pronase, cofactor peptides were purified by hplc and sequenced. for thermolytic peptides, a typical topa consensus sequence, asn-x ... | 1996 | 8679675 |
| solution structure of the granular starch binding domain of glucoamylase from aspergillus niger by nuclear magnetic resonance spectroscopy. | the solution structure of the granular starch binding domain (sbd) of glucoamylase 1 from aspergillus niger has been determined by heteronuclear multidimensional nuclear magnetic resonance spectroscopy and simulated annealing. a total of 1092 nuclear overhauser enhancement-derived 1h-1h distance constraints, 137 dihedral constraints and 86 hydrogen bond constraints were incorporated into an x-plor simulated annealing and refinement protocol. the family of calculated structures shows a well defin ... | 1996 | 8683599 |
| inhibition of polyphenol oxidase by copper-metallothionein from aspergillus niger. | metallothionein from aspergillus niger was found to be an inhibitor, in a model system, for the enzymic activity of a commercially purified mushroom tyrosinase. the inhibitory effect of metallothionein was higher on catechin oxidation compared with that on chlorogenic acid. the degree of inhibition of enzymic colour formation by metallothionein, using catechin as substrate, was lower than that of oxygen uptake; however, a reverse pattern was observed with chlorogenic acid as substrate. the demet ... | 1996 | 8688193 |
| kitchens as a source of aspergillus niger infection. | in this study we investigated the epidemiology of a cluster of cutaneous infections owing to aspergillus niger, which occurred in neutropenic patients in a bone marrow transplant unit. heavy environmental contamination with the mould was found in the ward kitchen adjacent to the unit. the clinical and environmental isolates were typed by random amplification of polymorphic dna (rapd), which showed one of the patients was infected with the same strain as that isolated repeatedly from the kitchen ... | 1996 | 8690882 |
| comparison of antimicrobial properties of monoterpenes and their carbonylated products. | some monoterpenes and their carbonylated products were evaluated for their antibacterial and antifungal properties. the carbonylation of tested monoterpenes was shown to increase the bacteriostatic and fungistatic activities specifically by the contact method. concerning the killing effects, only (1r,2s,5r)-isopulegol, its carbonylated products, and (r)-carvone showed significant bactericidal activities, particularly against enterococcus faecium and escherichia coli above a concentration of 10 m ... | 1996 | 8693045 |
| reversible inhibition and irreversible inactivation of catalase in presence of hydrogen peroxide. | spectroscopic and kinetic investigations have been carried out on catalase from bovine liver and from aspergillus niger to address the mechanism of activity loss at high hydrogen peroxide concentrations (0.01 to 2 m). the mammalian enzyme was both reversibly inhibited and irreversibly inactivated in the presence of hydrogen peroxide, whereas the fungal enzyme did not show any reversible inhibition. a comparison of reaction rates with catalase preparations containing different proportions of comp ... | 1996 | 8695649 |
| trapping of different lipase conformers in water-restricted environments. | based on a recently reported strategy to rationally activate lipolytic enzymes for use in nonaqueous media [mingarro, i., et al. (1995) proc. natl. acad. sci. u.s.a. 92, 3308-3312], we compared the behavior in water-restricted environments of activated vs nonactivated forms of different lipases toward their natural substrates, triacylglycerols. to this end, nine lipases from varied origins (mammalian, fungal, and bacterial) were assayed using simple acidolyses as nonaqueous model reactions. the ... | 1996 | 8703968 |
| rapid and sensitive screening of antifungal activity in medicinal plants by a single-cell biosensing system. | a biosensing system based on the response of fungal cells was used for the evaluation of antifungal activity of medicinal plants against aspergillus niger. this system measured the hyphal growth rate in real time in the presence or absence of chinese herbal extracts. the sensitivity of this system was 100-fold higher than that of conventional methods, and is advisable for the screening of antifungal compounds. | 1996 | 8704324 |
| regulation of acid phosphatases in an aspergillus niger pacc disruption strain. | an aspergillus niger strain has been constructed in which the ph-dependent regulatory gene, pacc, was disrupted. the pacc gene of a. niger, like that of a. nidulans, is involved in the regulation of acid phosphatase expression. disruptants were identified by a reduction in acid phosphatase staining of colonies. southern analysis demonstrated integration of the disruption plasmid at the pacc locus and northern analysis showed that the disruption strain produced a truncated pacc mrna of 2.2 kb (as ... | 1996 | 8709960 |
| influence of fungi associated with bananas on nutritional content during storage. | botryodiplodia theobromae, rhizopus oryzae, aspergillus niger, a. flavus and fusarium equiseti were found to be associated with the ripening of bananas and also caused rot during storage. bananas stored in baskets with ash fire wood ripened 2-3 days earlier than bananas stored in fibre sacks and under constant light. the infected bananas showed a decrease in the quantity of total soluble sugars, protein, lipid, crude fibre, ash, ascorbic acid and mineral elements when compared with the control f ... | 1996 | 8711953 |
| the single-batch bioconversion of wheat straw to ethanol employing the fungus trichoderma viride and the yeast pachysolen tannophylus. | we have developed and optimized a single-batch process of the production of ethanol from wheat straw employing the fungus trichoderma viride and the yeast pachysolen tannophylus. t. viride and aspergillus niger were examined for their ability to produce fermentable sugars from cellulosic waste materials, e.g. different kinds of straw and wood waste. t. viride most efficiently saccharified delignified wheat straw within 3 days at 25-30 degrees c with a yield of reducing sugars of 27 g from 50 g d ... | 1996 | 8737576 |
| integration of glucoamylase gene from aspergillus niger into saccharomyces cerevisiae genome and its stable expression. | starch digestible delta-integrants were constructed by integrative transformation of a linear yip plasmid carrying aspergillus niger glucoamylase cdna under the control of the mf alpha 1 promoter and its prepro signal and the delta sequence of the ty element from yeast. the integration of glucoamylase cdna into saccharomyces cerevisiae was identified by southern analysis. the secreted glucoamylase activity of integrants in the medium with soluble starch as a carbon source reached 2.5 u/ml. after ... | 1995 | 8739101 |
| [sero-diagnosis for pulmonary aspergillosis--its utility in early diagnosis]. | the clinical utility of pastorex aspergillus, a commercially available circulating aspergillus galactomannan antigen detection kit was evaluated. in animal models of pulmonary aspergillosis, it was extremely sensitive for detection of not only a. fumigatus antigen but also antigens of a. flavus and a. niger both in serum and urine. in a preliminary study in autopsied or clinically proven cases with aspergillus infections a high positive rate of antigen detection was obtained when it was applied ... | 1996 | 8752728 |
| the cu,zn superoxide dismutases of aspergillus flavus, aspergillus niger, aspergillus nidulans, and aspergillus terreus: purification and biochemical comparison with the aspergillus fumigatus cu,zn superoxide dismutase. | cu,zn superoxide dismutases (sods) have been purified to homogeneity from aspergillus flavus and a. niger, which are significant causative agents of aspergillosis, and from a. nidulans and a. terreus, which are much rarer causative agents of disease, using a combination of isoelectric focusing and gel filtration fast protein liquid chromatography. the purified enzymes have been compared with the previously described sod from the most important pathogen in the genus, a. fumigatus (m. d. holdom, r ... | 1996 | 8757871 |
| expression pattern of aspartic proteinase antigens in aspergilli. | sporulating colonies of aspergillus fumigatus, a. flavus, and a. niger were subjected to immunofluorescence using specific polyclonal antibodies against the aspergillopepsin pep (ec 3.4.23.18), a secretory aspartic proteinase produced by a. fumigatus. the proteinase antigen was found mainly in developing conidiophores of aspergilli, in submerged mycelia and on the tips of growing aerial mycelia. mature aerial hyphae and spores showed no immunofluorescence at all. sporulating conidiophores reveal ... | 1996 | 8767001 |
| [effect of zinc oxide on aspergillus species: a possible cause of local noninvasive aspergillosis of the maxillary sinus]. | during the last years the appearance of radiopaque concrements in the maxillary sinus was reported. these 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 development of a local, non-invasive aspergillosis. therefore, we tested aspergillus fumigatus, a. flavus, a. terreus, a. nidulans and a. niveus for the influence of zinc oxide. cza-pek-do ... | 1996 | 8767264 |
| enhancement and repression of cyanide-insensitive respiration in aspergillus niger. | the biosynthesis of the alternative oxidase protein consisting of cyanide-insensitive and salicylhydroxamic acid-sensitive respiration in aspergillus niger was investigated. cyanide-insensitive respiration was enhanced by addition of antimycin a to the incubation mixture, but repressed by the addition of cycloheximide, emetine, puromycin (cytosolic translation inhibitors), carbonylcyanide-m-chlorophenylhydrazone (uncoupler) and actinomycin d (transcription inhibitor). these results show that the ... | 1996 | 8768530 |
| fungal fermentation of whey incorporated with certain supplements for the production of proteases. | the pattern and the extent of formation of proteases and secretion varied with the fungus, age and/or the nature of the co-supplement. addition of yeast extract induced the best yield of proteases from both aspergillus niger and a. terreus. proteases from a. niger were highly induced by glutamic acid, alanine or albumin, with minor differences, whereas gelatin, peptone, aspartic acid, casein or acetamide stimulated the accumulation of proteases in the culture medium of a. terreus. galactose stim ... | 1996 | 8771776 |
| the efficacy of an enzymic cocktail and a fungal mycelium in dephosphorylating corn-soybean meal-based feeds fed to growing turkeys. | a study was conducted to determine the efficacy of phytase, an enzymic cocktail, and a waste aspergillus niger mycelium to hydrolyze phytate present in corn-soybean meal diets. one hundred turkey poults were assigned to dietary treatments for 2 wk (days 7 to 21). dietary treatments included: 1) nrc (1994) diet (nrc), with recommended concentration of 0.6% available p (ap) and 1.2% ca; 2) phytase diet (phyt), 1,000 units phytase/kg diet, 0.16% ap, and 0.84% ca; 3) cocktail diet (coc), 1,000 units ... | 1996 | 8778733 |
| isolation by genetic complementation of two differentially expressed genes for beta-isopropylmalate dehydrogenase from aspergillus niger. | we have constructed an aspergillus niger cdna library with a yeast expression vector. the library dna complemented a leucine auxotroph of saccharomyces cerevisiae (strain bwg1-7a) at a frequency of 4x10(-4). plasmids rescued from the yeast prototrophs also complemented escherichia coli (strain mc1066) deficient in leucine biosynthesis. sequence determination of the rescued plasmids revealed two genes for beta-isopropylmalate dehydrogenase, which we called leu2a and leu2b. genomic-blot analysis s ... | 1996 | 8781173 |
| production of cytokines by alveolar and peritoneal macrophages stimulated by aspergillus fumigatus conidia or hyphae. | aspergillus fumigatus is an opportunistic pathogen responsible for severe, invasive infections in neutropenic hosts. lung clearance of a. fumigatus conidia seems to be mediated by phagocytic cells and oxygen radicals. it is not known if cytokines or nitrogen radicals are also involved. we tested for the production of tnf alpha, il-1 and nitric oxide (no) after stimulation of mouse macrophages with the fungus. we found that both cytokines, but not no, were produced in a dose-dependent manner duri ... | 1996 | 8786471 |
| analysis of heterologous protein production in defined recombinant aspergillus awamori strains. | a study was carried out to obtain more insight into the parameters that determine the secretion of heterologous proteins from filamentous fungi. a strategy was chosen in which the mrna levels and protein levels of a number of heterologous genes of different origins were compared. all genes were under control of the aspergillus awamori 1,4-beta-endoxylanase a (exla) expression signals and were integrated in a single copy at the a. awamori pyrg locus. a northern (rna) analysis showed that large di ... | 1996 | 8787393 |
| preliminary characterization of a new exo-beta-(1,4)-galactanase with transferase activity. | as a prerequisite to the study of the fine chemical structure of the branched region of pectin, an exo-beta-(1,4)-galactanase was purified from a commercial preparation (pectinex ar). purification was carried out by precipitation with 70% saturated ammonium sulfate, preparative electrofocusing, anion-exchange chromatography and affinity chromatography on cross-linked alginate. exogalactanase specific activity was 992 nkat mg-1 and the enzyme was devoid of beta-(1,3)- or beta-(1,6)-galactanase, a ... | 1995 | 8789338 |
| influence of medium components and metabolic inhibitors on glucose oxidase production by aspergillus niger mycelium. | the effect of some medium components and metabolic inhibitors on glucose oxidase (god) production by mutant aspergillus niger was studied in shaken culture. altering the composition of the basal medium, particularly substitution of (nh4)2hpo4 for nano3, and lack of mg2+ ions caused an increase in god activity by 269.6%. the highest yield of extracellular god activity of a. niger mycelium was obtained in the presence of hematin (1 mm), choline (40 mm) and tween 80 (0.1%), which improved the activ ... | 1996 | 8795255 |
| control of microbial contamination in unpreserved eyedrops. | preservatives are added to multidose eyedrop containers to ensure that the eyedrops do not become heavily contaminated during patient use. this enables eyedrops to be used for up to 1 month after opening. however, patients are frequently required to use unpreserved eyedrops as their eyes are unable to tolerate these preservatives. some commercial unpreserved unit dose eyedrops are available, but the range is limited, and they cannot be used in all cases. twenty one different unpreserved eyedrop ... | 1996 | 8795368 |
| effect of fermentation conditions on the production of citric acid from cheese whey by aspergillus niger. | the effect of ph value, methanol, and salt concentration on the production of citric acid from cheese whey by two strains of aspergillus niger, i.e. caim 111 and caim 167, was investigated. lactose concentration, utilized lactose, citric acid concentration, conversion coefficient of lactose to citric acid, and mycelial dry weight were measured during the fermentation process. the maximum citric acid concentration (1.06 and 0.82 g/l), and conversion coefficient (5.58 and 7.45%) were obtained at p ... | 1996 | 8796442 |
| three alpha-galactosidase genes of trichoderma reesei cloned by expression in yeast. | three alpha-galactosidase genes, agl1, agl2 and agl3, were isolated from a cdna expression library of trichoderma reesei rutc-30 constructed in the yeast saccharomyces cerevisiae by screening the library on plates containing the substrate 5-bromo-4-chloro-3-indolyl-alpha-d-galactopyranoside. the genes agl1, agl2 and agl3 encode 444, 746 and 624 amino acids, respectively, including the signal sequences. the deduced amino acid sequences of agli and agliii showed similarity with the alpha-galactosi ... | 1996 | 8797842 |
| lysis and biological control of aspergillus niger by bacillus subtilis af 1. | a biocontrol rhizobacterial strain of bacillus subtilis af 1 grown for 6 h was coinoculated with aspergillus niger at different time intervals and microscopic observations revealed adherence of bacterial cells to the fungal mycelium. bacterial cells multiplied in situ and colonized the mycelial surface. growth of af 1 resulted in damage to the cell wall, followed by lysis. af 1 inoculation into media containing a. niger at 0, 6, and 12 h suppressed > 90% fungal growth, while in 18- and 24-h cult ... | 1996 | 8801004 |
| characteristics of streptomyces strains isolated from soils in two landfill areas in north jordan. | a total of 114 streptomyces strains were isolated and purified from soils collected from al akider (53) and from al kafeer (61) landfill areas in north jordan. the al akider strains were classified into 5 colour series gray (27), white (18), yellow (3), violet (3) and green (2); while the al kafeer strains were classified into 6 colour series white (26), gray (16), yellow (9), red (2), green (7) and blue (1). melanin pigment was produced by 21 and 25% of the al akider and al kafeer strains, resp ... | 1996 | 8806943 |
| fungal contamination of potential medical interest in spanish grain stores. | a one-year study was made of fungal spores detected in the air and in the grain of two silos and two seed stores near córdoba, spain. gravimetric and volumetric methods were used simultaneously on culture mediums to sample the air. the dilution method was employed to analyze seed contamination. a total of 70 taxa were isolated, 67 of these from the air and 46 in seeds. the most abundant airborne taxa were: aspergillus oryzae, cladosporium cladosporioides and yeast, while yeast, a. niger and a. o ... | 1996 | 8807511 |
| influence of sundrying on the chemical composition, aflatoxin content and fungal counts of two pepper varieties--capsicum annum and capsicum frutescens. | samples of sundried, matured red pepper, capsicum annum with a moisture content (mc) of 12.7-26.8 percent had on dry weight basis, vitamin c, 5.0-6.4 mg/100 g; crude protein, 0.8-1.2 percent; total soluble solids, 3.3-4.1 percent, and fungal counts of log 4.4-4.5/g. ordinary matured red c. annum had mc, 75.7-78.2 percent vitamin c, 36.1-38.5 mg/100 g; crude protein, 2.4-2.8 percent; total soluble solids, 9.3-9.9 percent and fungal count of log 3.32-3.39/g. sundried matured red c. frutescens had ... | 1996 | 8811723 |
| a homologous and self-replicating system for efficient transformation of fusarium oxysporum. | a highly efficient transformation system has been developed for fusarium oxysporum f. sp. lycopersici based on the complementation of a nitrate-reductase mutant with the homologous nit1 gene and on the presence of ars and telomeric sequences in the vector. preliminary transformation experiments with the niad gene from aspergillus niger generated self-replicating plasmids within the transformed entity that contained extra-fungal dna. a fragment of the extra dna was inserted into puc19 together wi ... | 1996 | 8821667 |
| n-terminal sequence of amino acids and some properties of an acid-stable alpha-amylase from citric acid-koji (aspergillus usamii var.). | an acid-stable alpha-amylase (aa) was purified from an acidic extract of citric acid-koji (a. usamii var.). the n-terminal sequence of the first 20 amino acids of the enzyme was identical with that of aa from a. niger, but the two enzymes differed in molecular weight. hplc analysis for identifying the anomers of products indicated that the aa hydrolyzed maltopentaose (g5) at the third glycoside bond predominantly, which differed from taka-amylase a and the neutral alpha-amylase (na) from the cit ... | 1996 | 8824843 |
| novel hexacyanoferrate (iii)-modified carbon electrodes: application in miniaturized biosensors with potential for in vivo glucose sensing. | we adapted a new technology for the modification of carbon base electrodes for use as probe-type, potentially implantable glucose sensors. carbon rods (diameter 0.3 mm) were modified by repeated potential cycling in 0.1 m potassium hexacyanoferrate (iii). the modified-carbon electrodes were sealed in plastic pipette tips with an exposed reaction area where glucose oxidase was immobilized using glutaraldehyde. an outer membrane of nafion, followed by 15% (w/v) polyurethane, was applied over the e ... | 1996 | 8828167 |
| [ultrastructural study of the action of cyclosporine on cells of the fungus aspergillus niger]. | electron microscopy of the ultrastructure of the aspergillus niger cells exposed to cyclosporine in acute experiments revealed changes in the mycelium morphology, hyphae growth and cell structure in the organism sensitive to cyclosporine. the analysis of the changes showed that the primary target of the cyclosporine action was the cell cytoplasmic membrane. the changes in the matrix of the cytoplasmic membrane, mitochondria and cell wall were likely mediated or secondary after the impairment of ... | 1995 | 8830638 |
| cinnamon bark oil, a potent fungitoxicant against fungi causing respiratory tract mycoses. | cinnamic aldehyde has been identified as the active fungitoxic constituent of cinnamon (cinnamomum zeylanicum) bark oil. the fungitoxic properties of the vapours of the oil/active constituent against fungi involved in respiratory tract mycoses, i.e., aspergillus niger, a. fumigatus, a. nidulans a. flavus, candida albicans, c. tropicalis, c. pseudotropicalis, and histoplasma capsulatum, were determined in vitro as minimum inhibitory concentration (mic), minimum lethal concentration (mlc), inoculu ... | 1995 | 8834832 |
| raw-starch-digesting and thermostable alpha-amylase from the yeast cryptococcus sp. s-2: purification, characterization, cloning and sequencing. | a starch-degrading enzyme produced by the yeast cryptococcus sp. s-2 was purified in only one step by using an alpha-cyclodextrin-sepharose 6b column, and was characterized as an alpha-amylase (ec 3.2.1.1). the molecular mass and isoelectric point of purified alpha-amylase (amy-cs2) were estimated to be 66 kda and 4.2 respectively. amy-cs2 has raw-starch-digesting and raw-starch-absorbing activities. furthermore it was shown to be thermostable. an open reading frame of the cdna specified 611 ami ... | 1996 | 8836148 |
| molecular polymorphism and phenotypic variation in aspergillus carbonarius. | thirteen collection strains and field isolates of aspergillus carbonarius were examined by using various genotypic and phenotypic approaches. restriction fragment length polymorphism analysis of the ribosomal rna gene cluster and the mitochondrial dna of the strains revealed only slight variations, except for one field isolate (in7), which exhibited completely different ribosomal rna gene cluster and mitochondrial dna patterns. the mitochondrial dnas of these strains were found to be much larger ... | 1996 | 8836442 |
| microbial hydroxylation of 13-ethyl-17 beta-hydroxy-18,19-dinor-17 alpha-pregn-4-en-20-yn-3-one. | the microbial transformation of the racemic mixture of 13-ethyl-17 beta-hydroxy-18,19-dinor-17 alpha-pregn-4-en-20-yn-3-one (1) was investigated. rhizopus nigricans (as 3.2050), r. arrhizus (as 3.4523), aspergillus niger (as 3.2744), a. ochraceus (as 3.1408), and curvularia lunata (nrrl 4381) transformed 1 into its 10 beta-hydroxy derivative (2) as a major metabolite. biotransformation of 1 by aspergillus ochraceus as 3.1408 afforded 7 beta-hydroxy derivative (3) as the only product. | 1996 | 8837292 |
| tailing of thermal inactivation curve of aspergillus niger spores. | the nonlinear thermal inactivation of aspergillus niger spores in phosphate-citrate buffer was studied. the thermal inactivation pattern of the spore consisted of a shoulder, an accelerated decline, and a tail at various constant temperatures around 60 degrees c. the pattern fitted a thermotolerant subpopulation model. in the model, we postulated that some spores in the initial population had become thermotolerant at a certain ratio during heating. the model parameters including the rate coeffic ... | 1996 | 8837430 |
| cloning of genes encoding alpha-l-arabinofuranosidase and beta-xylosidase from trichoderma reesei by expression in saccharomyces cerevisiae. | a cdna expression library of trichoderma reesei rutc-30 was constructed in the yeast saccharomyces cerevisiae. two genes, abf1 and bxl1, were isolated by screening the yeast library for extracellular alpha-l-arabinofuranosidase activity with the substrate p-nitrophenyl-alpha-l-arabinofuranoside. the genes abf1 and bxl1 encode 500 and 758 amino acids, respectively, including the signal sequences. the deduced amino acid sequence of abfi displays high-level similarity to the alpha-l-arabinofuranosi ... | 1996 | 8837440 |
| comparative fungicidal activity of a new quaternary ammonium salt, n-alkyl-n-2-hydroxyethyl-n,n-dimethylammonium butyl phosphate and commonly used disinfectants. | we synthesized a new quaternary ammonium salt, n-alkyl-n-2-hydroxyethyl-n, n-dimethylammonium butyl phosphate (abp) that does not precipitate in the presence of anionic surfactants by incorporating a paired butyl phosphate anion into cationic surfactants. abp showed much greater bactericidal activities and antirusting effects than benzalkonium chloride (bac). in this study, the fungicidal effects of abp were evaluated in comparison with common disinfectants [bac, chlorhexidine digluconate (chx) ... | 1996 | 8850330 |
| antimicrobial activity of pseudomonas spp. against food poisoning bacteria and moulds. | the present study demonstrates the siderophore production of two strains of pseudomonas fluorescens and two of ps. chlororaphis. the antimicrobial activities of these strains were studied against salmonella typhimurium, staphylococcus aureus, fusarium culmorum, f. oxysporum and aspergillus niger. despite equal siderophore activities with various pseudomonas spp. as measured by the chrome azurol s assay, the study shows how siderophore activity does not correlate with the antibacterial activity a ... | 1996 | 8852350 |
| cloning and biochemical characterisation of an aspergillus niger glucokinase. evidence for the presence of separate glucokinase and hexokinase enzymes. | the aspergillus niger glucokinase gene glka has been cloned using a probe generated by polymerase chain reaction with degenerate oligonucleotides. the dna sequence of the gene was determined, and the deduced amino acid sequence shows significant similarity to other eukaryotic hexokinase and glucokinase proteins, in particular to the saccharomyces cerevisiae glucokinase protein. the encoded protein was purified from a multicopy glka transformant, and extensively characterised. the protein has a m ... | 1996 | 8856049 |
| primary structure and characterization of an exopolygalacturonase from aspergillus tubingensis. | from the culture fluid of the hyphal fungus aspergillus tubingensis, an exopolygalacturonase with a molecular mass of 78 kda, an isoelectric point in the ph-range 3.7-4.4 and a ph optimum of 4.2 was purified. the enzyme has been characterized as an exopolygalacturonase [poly(1,4-alpha-d-galacturonide)galacturonohydrolase] that cleaves monomer units from the non-reducing end of the substrate molecule. k(m) and vmax for polygalacturonic acid hydrolysis were 3.2 mg ml-1 and 3.1 mg ml-1 and 255 u mg ... | 1996 | 8856078 |
| purification and properties of carnitine acetyltransferase from citric acid producing aspergillus niger. | carnitine acetyltransferase was purified from the citric acid producing a. niger mycelium with a protein band showing a relative molecular weight of 77,000 and a ph optimum of 7.3. the k(m) values for the purified enzyme for acetyl-coa and for carnitine were 0.1 mm and 1 mm, respectively. carnitine acetyltransferase was located both in the mitochondria and in the cytosol. both mitochondrial and cytosolic enzyme were purified using ammonium sulfate precipitation, mono q and superose 12 separation ... | 1996 | 8856942 |
| phytase. | of all the sources of phytase that have been studied (plant, animal, and microorganisms), the highest yields are produced by a wild-type strain a. niger nrrl 3135 (12.7 mg p/hr/ml = 6.8 microns p/ml/min = 113.9 nkat/ml) in a mineral salt medium in which total phosphate (4 mg %) is limiting for growth and cornstarch and glucose are the carbon sources. synthesis of the enzyme is repressed by phosphate in the wild-type strain. aspergillus niger nrrl 3135 produces two phytases one with ph optima at ... | 1996 | 8865587 |
| comparison of kinetic properties between plant and fungal amine oxidases. | kinetic properties of novel amine oxidases isolated from a mold aspergillus niger aku 3302 were compared to those of typical plant amine oxidase from pea seedling (ec 1.4.3.6). pea amine oxidase showed highest affinity with diamines, such as putrescine and cadaverine, while fungal enzymes oxidized preferably n-hexylamine and tyramine. all enzymes were inhibited by carbonyl reagents, copper chelating agents, some substrate analogs and alkaloids, but there were quite significant differences in the ... | 1996 | 8872745 |
| an attempt on using the method of r-q double-factor analysis to identify and group fusants. | a subsequent numeric taxonomy method for identifying and grouping the fusants was explored on the basis of characterization of the protein profiles of the fusants. by these two means, several typical excellent candidates of recombinants could be searched out quickly. among the fusants from a definite fusion-cross, the different sister-strains were regarded as the samples of observation (n = n), the positions of the all bands of protein profiles as the objects (p = p), and the photometer-scanning ... | 1996 | 8877112 |
| raw starch digestion. | | 1996 | 8878926 |
| a major bioactive component of plant cell walls, ferulic acid, influences feruloyl esterase production in aspergillus niger. | | 1996 | 8878930 |
| increased resistance to 14 alpha-demethylase inhibitors (dmis) in aspergillus niger by coexpression of the penicillium italicum eburicol 14 alpha-demethylase (cyp51) and the a. niger cytochrome p450 reductase (cpra) genes. | in this paper we describe the effects of over-expression of the penicillium italicum gene encoding eburicol 14 alpha-demethylase (cyp51), in aspergillus niger strains with one or multiple copies of the gene encoding cytochrome p450 reductase (cpra), on the eburicol 14 alpha-demethylase activity. eburicol 14 alpha-demethylase activity was determined by measuring the resistance of transformants against some eburicol 14 alpha-demethylase inhibitors (dmis). dmis are widely used as fungicides in crop ... | 1996 | 8879162 |
| glycerol is not an inhibitor of mitochondrial citrate oxidation by aspergillus niger. | we have re-assessed the hypothesis that an accumulation of intracellular glycerol triggers the accumulation of citric acid by aspergillus niger by inhibiting the activity of the mitochondrial nadp-dependent isocitrate dehydrogenase isoenzyme. to this end, we have incubated mycelia of a. niger with 0.5 m glycerol, which resulted in a maximal intracellular glycerol pool level of 0.92 m, comparable to that determined during the early phase of citrate accumulation. this addition affected neither the ... | 1996 | 8885410 |
| the spectrum of orbital aspergillosis: a clinicopathological review. | orbital aspergillosis is an uncommon but serious infection that may first present to the ophthalmologist. usually arising from the paranasal sinuses, it may present in manifold ways within the orbit. some presentations, such as optic nerve involvement, can respond to systemic corticosteroids, leading to delays in diagnosis and possibly iatrogenic potentiation of the infectious process. in this review, pertinent clinical and radiographic findings are discussed, and the literature is summarized. c ... | 1996 | 8890440 |
| three-dimensional structure of endo-1,4-beta-xylanase i from aspergillus niger: molecular basis for its low ph optimum. | the crystal structure of endo-1,4-beta-xylanase i from aspergillus niger has been solved by molecular replacement and was refined to 2.4 a resolution. the final r-factor for all data from 6 to 2.4 a is 17.9%. the a. niger xylanase has a characteristic fold which is unique for family g xylanases (root-mean-square deviation = 1.1 a to trichoderma reesei xylanase i, which has 53% sequence identity). it consists of a single domain composed predominantly of beta-strands. two beta-sheets are twisted a ... | 1996 | 8890913 |
| structure and energetics of the glucoamylase-isomaltose transition-state complex probed by using modeling and deoxygenated substrates coupled with site-directed mutagenesis. | molecular recognition, site-directed mutagenesis, and molecular modeling are combined to describe hydrogen bonds important for formation and catalysis of the aspergillus niger glucomylase-isomaltose complex. this analysis of the energetics of the transition-state complex identified oh-4', -6', and -4 as critical for isomaltose hydrolysis. side-chains hydrogen bonded to isomaltose oh-4 (reducing end unit, i.e. at glucoamylase binding subsite 2) induced substrate conformation adjustment to optimiz ... | 1996 | 8890914 |
| construction of a promoter probe vector autonomously maintained in aspergillus and characterization of promoter regions derived from a. niger and a. oryzae genomes. | we used a plasmid carrying a sequence for autonomous maintenance in aspergillus (ama1) and the e. coli uida gene as a reporter gene to search the a. oryzae and a. niger genomes for dna fragments having strong promoter activity. beta-glucuronidase (gus)-producing a. oryzae transformants containing the no. 8an derived from a. niger, or the no. 9ao derived from a. oryzae, were constitutive for the expression of the uida gene when cultivated in the presence of a variety of carbon and nitrogen source ... | 1996 | 8901095 |
| detection of endogenous beta-glucuronidase activity in aspergillus niger. | an endogenous beta-glucuronidase that hydrolyses the chromogenic substrate 5-bromo-4-chloro-3-indolyl-beta-d-glucuronide (x-gluc) in aspergillus niger is reported. the activity was induced when the fungus was grown in media containing xylan, but was either very low, or absent, when grown on glucose. endogenous beta-glucuronidase was primarily located in newly formed hyphae, and was apparent at ph values between 3 and 6. hydrolysis of x-gluc was sensitive to the inhibitor d-saccharic acid 1,4-lac ... | 1996 | 8920195 |
| pectin methyl esterase from aspergillus aculeatus: expression cloning in yeast and characterization of the recombinant enzyme. | seventeen full-length cdnas encoding pectin methyl esterase i (pme i) have been isolated from the filamentous fungus aspergillus aculeatus by expression cloning in yeast. yeast colonies expressing functional pme i were identified on agar plates containing highly esterified pectin, and a cdna encoding pme i was isolated. the deduced amino acid sequence of pme i is highly similar (74% identity) to the pme from aspergillus niger. a full-length cdna encoding pme i was cloned into an aspergillus expr ... | 1996 | 8920970 |
| modification of tomato and aspergillus niger pectinesterases with diethyl pyrocarbonate. | the role of histidine residues in pectinesterases was evaluated by monitoring the sensitivity to modification with diethyl pyrocarbonate in the tomato and aspergillus niger enzymes. different and incomplete losses of enzyme activity were obtained. inactivation of the enzymes was proportional to the histidine content (two in the tomato t1 form, six in the aspergillus form), suggesting that accessible histidine residues do not have active-site functions in these pectinesterases, but contribute to ... | 1996 | 8924197 |
| attenuated virulence of uridine-uracil auxotrophs of aspergillus fumigatus. | aspergillus fumigatus mutants that are deficient in the de novo ump biosynthesis pathway because of a mutation in the pyrg gene encoding orotidine-5'-phosphate decarboxylase (and therefore auxotrophic for uridine or uracil) were evaluated in a murine model of invasive aspergillosis. these mutants were entirely nonpathogenic, and mutant conidia remained ungerminated in alveolar macrophages. both the germination and virulence defects could be restored by supplementing the drinking water of the ani ... | 1996 | 8926121 |
| identification of regulatory mutants of aspergillus aculeatus affected in rhamnogalacturonan hydrolase expression. | rhamnogalacturonan hydrolase expression in a. aculeatus can be induced by pectin, but also by a combination of two constituent monosaccharides of pectin, rhamnose and galacturonic acid. the rhga promoter was fused to the a. niger glucose oxidase coding sequence and a single copy of the hybrid gene was integrated at the rhga locus in the genome of a. aculeatus. the gene product was subsequently used as reporter in a screening assay for the selection of rhamnogalacturonan hydrolase-overproducing m ... | 1996 | 8929397 |
| protein partitioning equilibrium between the aqueous poly(ethylene glycol) and salt phases and the solid protein phase in poly(ethylene glycol)-salt two-phase systems. | true partitioning behaviour, which is independent of the protein concentration in aqueous two-phase systems, only occurs at relatively low protein concentration. the actual concentration limit depends on the properties of the protein. when the concentration of a protein exceeds relatively low values, precipitation at the interface can be observed. this protein precipitate is in equilibrium with the protein solubilized in each of the phases. this paper discusses the effect of protein solubility i ... | 1996 | 8930748 |
| cloning and expression of the alpha-l-arabinofuranosidase gene (abf2) of aspergillus niger in saccharomyces cerevisiae. | first-strand cdna was prepared from mrna of aspergillus niger mrc11624 induced on oat spelts xylan. using the cdna as a template, the alpha-l-arabinofuranosidase gene (abfb) was amplified with the polymerase chain reaction technique. the abfb dna fragment was inserted between the yeast phosphoglycerate kinase i gene promoter (pgk1p) and terminator (pgk1t) sequences on a multicopy episomal plasmid. the resulting construct pgk1p-abfb-pgk1t was designated abf2. the abf2 gene was expressed successfu ... | 1996 | 8933843 |
| isolation of a tannin-protein complex-degrading fungus from faeces of hill cattle. | faecal samples of 52 hill cattle fed largely on oak leaves were screened for tannin-protein complex-degrading micro-organisms under different culture conditions using tannin-treated brain heart infusion agar medium. none of the animals were found to harbour tannin-protein complex-degrading enterobacteria. however, a fungus identified as aspergillus niger van tieghem having tannin-protein complex-degrading activity, was consistently isolated from the faeces of such animals. optimum growth and spo ... | 1996 | 8934781 |
| [zinc, pregnancy and the fetus]. | | 1996 | 8935673 |
| hypersensitivity reactions and specific antibodies in workers exposed to industrial enzymes at a biotechnology plant. | thirty-six employees who produced industrial enzymes from selected strains of bacteria and fungi were evaluated by epicutaneous threshold testing and enzyme-linked immunosorbent assays (elisa) for specific ige and igg antibodies. the workers complained of 'asthma- and flu-like' symptoms, which generally lessened away from work. the enzymes evaluated were: alpha-amylase (1,4-alpha-d-glucan glucanohydrolase) from bacillus licheniformis (alpha abl), b. subtilis formation 1 (alpha a1bs) and b. subti ... | 1996 | 8935788 |
| triorganosilicon (iv) compounds: synthesis, structural study, and biological activity. | a few coordination compounds of silicon (iv) have been synthesized by the interaction of trimethyl- and triphenyl-chlorosilane with nitrogen-sulphur donor ligands. these compounds are monomeric, as indicated by molecular weight determination, and they behave as nonelectrolytes in dry dmf. from the electronic, infrared, 1h, and 13c nmr spectral results, it has been concluded that in these compounds, silicon is penta-coordinated in a trigonal bipyramidal environment. an assessment of biological ac ... | 1996 | 8936423 |
| substrate binding mechanism of glu180-->gln, asp176-->asn, and wild-type glucoamylases from aspergillus niger. | glucoamylase (1,4-alpha-glucan glucohydrolase, ec 3.2.1.3) from aspergillus, of which the 3d structure is known, releases beta-d-glucose from the non-reducing ends of starch and other related oligo and polysaccharides, cleaving the alpha-1,4-bond positioned between subsites 1 and 2 in the enzyme-substrate complex. the presteady and steady state kinetics of two of the existing mutants, glu180-->gln and asp176-->asn, are presented here. the kinetic results are analyzed according to two reaction mo ... | 1996 | 8942667 |
| stereochemical course of hydrolysis catalyzed by arabinofuranosyl hydrolases. | the stereochemical course of hydrolysis catalyzed by various enzymes acting on arabinofuranosyl linkages has been determined. 1h-nmr analysis of the action of endo-(1-->5)-alpha-l-arabinanases from aspergillus niger and aspergillus aculeatus showed that both hydrolyze linear arabinan with inversion of configuration, and may therefore act via a single displacement mechanism. this is consistent with the a. niger enzyme's classification in glycosyl hydrolase family 43. the catalytic mechanisms of a ... | 1996 | 8946944 |
| sequence analysis and expression of the penicillium chrysogenum nitrate reductase encoding gene (niad). | the nitrate reductase gene (niad) of the filamentous fungus penicillium chrysogenum encodes a protein of 864 amino acids. the derived protein sequence shows 78% and 72% sequence identity to the corresponding aspergillus niger and a. nidulans proteins, respectively. the coding region of the penicillium gene is interrupted by six small introns, as deduced by comparison with the niad sequences of a. niger and a. nidulans, whereby the positions of the introns are perfectly conserved between these th ... | 1996 | 8950182 |
| localization of an endoglucanase and a xylanase from aspergillus niger in soybean by immunogold-cytochemical labeling. | | 1996 | 8958089 |
| [a study of otomycoses in yaoundé]. | the authors report the results of a six-month evaluation of otomycoses in the ent department of chu and the central hospital of yaoundé. we examined 2 592 patients of both sexes presenting with ear affections. the prevalence of otomycoses is 6,09%. this is an adult problem with both sexes equally affected. clinically the main symptoms were burning sensation in the ears, pruritus, sensation of fullness in the ear, hypoacousia and otorrhea. clinical lesions are of many types including myringitis, ... | 1996 | 8959931 |
| expression of human recombinant beta 2-microglobulin by aspergillus nidulans and its activity. | the light chain of hla class i protein (beta 2m) has been expressed in aspergillus nidulans. the cdna of beta 2m was modified using the polymerase chain reaction to include overlapping extensions for its subsequent fusion into an aspergillus vector. this fusion resulted in beta 2m cdna being flanked by the aspergillus awamori glucoamylase promoter and the aspergillus niger glucoamylase terminator. expression of beta 2m was induced by the addition of starch to the culture medium. in preliminary m ... | 1996 | 8960907 |
| expression in a wine yeast strain of the aspergillus niger abfb gene. | a recombinant wine yeast strain has been constructed expressing the gene coding for alpha-l-arabinofuranosidase b from aspergillus niger under the control of the yeast actin gene promoter. the protein is efficiently secreted by the recombinant yeast, allowing its purification and characterisation. the heterologous alpha-l-arabinofuranosidase b shows similar physico-chemical properties to the native enzyme. the wine produced in microvinification experiments using the recombinant yeast presents th ... | 1996 | 8961556 |
| deglycosylation of proteins for crystallization using recombinant fusion protein glycosidases. | obtaining high quality protein crystals remains a rate-limiting step in the determination of three-dimensional x-ray structures. a frequently encountered problem in this respect is the high or heterogeneous carbohydrate content of many eukaryotic proteins. a number of reports have demonstrated the use of enzymatic deglycosylation in the crystallization of certain glycoproteins. although this is an attractive tool, there are some problems that hinder the more widespread use of glycosidases in cry ... | 1996 | 8976570 |
| an aspergillus niger esterase (ferulic acid esterase iii) and a recombinant pseudomonas fluorescens subsp. cellulosa esterase (xy1d) release a 5-5' ferulic dehydrodimer (diferulic acid) from barley and wheat cell walls. | diferulate esters strengthen and cross-link primary plant cell walls and help to defend the plant from invading microbes. phenolics also limit the degradation of plant cell walls by saprophytic microbes and by anaerobic microorganisms in the rumen. we show that incubation of wheat and barley cell walls with ferulic acid esterase from aspergillus niger (fae-iii) or pseudomonas fluorescens (xy1d), together with either xylanase i from aspergillus niger, trichoderma viride xylanase, or xylanase from ... | 1997 | 8979352 |
| high incidence of aspergillus flavus and aflatoxins in stored groundnut in ghana and the use of a microbial assay to assess the inhibitory effects of plant extracts on aflatoxin synthesis. | groundnut samples from 21 selected markets in the 10 regions of ghana yielded high levels of the aflatoxigenic fungus aspergillus flavus on half-strength potato dextrose agar. the fungus was associated with 31.7 and 12.8%, respectively, of all damaged and undamaged kernels assayed. only 0.24% of total kernels assayed yielded a. parasiticus. other fungi detected from total kernels assayed were a. niger (34%), a. candidus (1.45%), a. tamarii (3.93%), a. ochraceous (5.26%), fusarium spp. (1.7%) pen ... | 1996 | 8981776 |