Showing papers on "Aspergillus niger published in 1973"
TL;DR: An identical glucan appears to be present in the cell walls of Penicillium chrysogenum as well as the spore cell Walls of both organisms, as evidenced by methylation studies.
73 citations
TL;DR: The findings indicate that gluconate is dehydrated into 2-keto-3-deoxy-gluconate (KDG), which then is cleaved into glyceraldehyde and pyruvate.
Abstract: A new nonphosphorylative pathway for gluconate degradation was found in extracts of a strain of Aspergillus niger. The findings indicate that gluconate is dehydrated into 2-keto-3-deoxy-gluconate (KDG), which then is cleaved into glyceraldehyde and pyruvate. 6-Phosphogluconate was not degraded under the same conditions. In addition, KDG was formed from glyceraldehyde and pyruvate. Very weak activity was obtained when glyceraldehyde 3-phosphate replaced glyceraldehyde in this reaction.
53 citations
53 citations
TL;DR: The action pattern and k2 values obtained with the oligouronides suggest that the binding site of the endopolygalacturonase contains four subsites and that the catalytic groups of the enzyme are located in the proximity of the first bond, counting from the reducing end, of the substrate segment bound in the complex.
Abstract: The action pattern and kinetics of an Aspergillus niger extracellular endopolygalacturonase were studied with oligogalacturoic acids (digalacturonic acid through hexagalacturonic acid) and their derivatives in which the terminal aldehyde group was reduced. The rate of hydrolysis catalyzed by the enzyme decreases with the shortening of oligogalacturonide chain length; digalacturonic acid is not hydrolyzed. With tetragalacturonic acid one productive complex is formed resulting in (1 + 3) cleavage. Two and three modes of cleavage occur with pentagalacturonic acid and hexagalacturonic acid, respectively. The enzyme is competitively inhibited by trigalacturonic acid whereas digalacturonic acid does not affect the activity. Reduced pentagalacturonic acid forms one productive complex. Reducing trigalacturonic acid and nonreducing digalacturonic acid are the products of the reaction. Lower reduced oligogalacturonic acids are not degraded by the enzyme.
The action pattern and k2 values obtained with the oligouronides suggest that the binding site of the endopolygalacturonase contains four subsites and that the catalytic groups of the enzyme are located in the proximity of the first bond, counting from the reducing end, of the substrate segment bound in the complex.
48 citations
TL;DR: A protein, purified from Red Kidney (Phaseolus vulgaris) beans for its ability to inhibit the endopolygalacturonase secreted by C. lindemuthianum, inhibits the A. niger endopoly Galactoruronase almost as efficiently as it inhibits the C.lindemUTHianum enzyme.
Abstract: Endopolygalacturonases have been purified from the extracellular enzymes of Colletotrichum lindemuthianum and Aspergillus niger. A protein, purified from Red Kidney (Phaseolus vulgaris) beans for its ability to inhibit the endopolygalacturonase secreted by C. lindemuthianum, inhibits the A. niger endopolygalacturonase almost as efficiently as it inhibits the C. lindemuthianum enzyme.
44 citations
TL;DR: Two hundred and fifty microorganisms were tested for their ability to produce β-D-xylopyranosidase and two of the best, Aspergillus niger and Penicillium wortmanni, were studied in greater detail for the first time.
Abstract: Two hundred and fifty microorganisms were tested for their ability to produce β-D-xylopyranosidase. Two of the best, Aspergillus niger and Penicillium wortmanni, were studied in greater detail for the effects of inducing compounds and of surfactants on yields. Under optimal conditions, culture filtrates were obtained which had specific activity values 10 to 60 times those of sources (sea snail, Bacillus, Chaetomium, hemicellulase) used by other investigators. In most instances, our unpurified filtrates had higher activities than did the extensively purified preparations from these other sources. The fungal β-D-xylopyranosidases hydrolyze aryl and alkyl β-D-xylopyranosides, oligomers of D-xylose, and L-serine β-D-xyloside. They do not hydrolyze β-D-xylosyl dextran, tomatin, or α-D-xylosides.
40 citations
28 citations
TL;DR: The maximum rate of hydrolysis (3.2 μmoles lactose/min per mg enzyme preparation) was obtained when lactose was 21% in whey concentrates.
25 citations
TL;DR: Chromatographic properties, presence of phosphorus, coloration with the anisaldehyde reagent and acid lability of the lipid suggest that this compound is a polyprenol-phosphate.
Abstract: Microsomal preparations from Aspergillus niger mediate transfer of mannosyl units from GDP-mannose to endogenous lipids. Mannosyltransferases require divalent cations for activity. Optimum pH, temperature maximal activity and optimal metal ion concentration are different whether Mn2+ or Mg2+ are used.
Km value for GDP-mannose is 0.2 μM in presence of Mg2+, while, with Mn2+, two values are obtained: 0.2 μM and 10 μM for low and high-substrate concentration.
The lipid acceptor is purified by fractionation of the lipid extract on silicic-acid column followed by thin-layer chromatography on silica gel.
Chromatographic properties, presence of phosphorus, coloration with the anisaldehyde reagent and acid lability of the lipid suggest that this compound is a polyprenol-phosphate.
23 citations
TL;DR: The results indicated that the microbial enzymes were specific for aromatic, or bulky and hydrophobic amino acid residues on both sides, as had been observed with pepsin.
23 citations
TL;DR: Only Aspergillus niger produced myrosinase, and the enzyme was unstable but was stabilized by coexistence with 2-mercaptoethanol and ascorbic acid.
Abstract: After Screening 100 micro-organisms to detect intracellular myrosinase, only Aspergillus niger produced myrosinase.Enzyme production was induced by the addition of ten percent of a mustard extract* to the culture medium. The enzyme was produced in considerable amounts on the first and second day of cultivation. L-Ascorbic acid was an excellent carbon source.The enzyme was unstable but was stabilized by coexistence with 2-mercaptoethanol (10−2 M) and ascorbic acid (10−3 M).
TL;DR: It is proposed that citric acid accumulation by Aspergillus niger may result from abnormal cyclic AMP metabolism, and theophylline enhanced the cyclicAMP effect.
TL;DR: Hydrolysis of lactose in acid whey by a β-galactosidase from Aspergillus niger followed by deproteinization at different pH values and subsequent incubation at low temperatures produced colorless to golden, sweet food syrups.
TL;DR: The enzyme-forming systems concerned with the amylase of Bacillus subtilis, and the glucamylase and acid protease of Aspergillus niger, have been shown to be highly stable in the cultural conditions applied owing to the low decay rate of mRNAs specific for these respective enzymes.
Abstract: The enzyme-forming systems (EFSs) concerned with the amylase of Bacillus subtilis, and the glucamylase and acid protease of Aspergillus niger, have been shown to be highly stable in the cultural conditions applied owing to the low decay rate of mRNAs specific for these respective enzymes. The quantity per cell of mRNAs for any of these enzymes is regarded as limiting the specific rate of enzyme production in the conditions used for enzyme production. Investigations on the repression, derepression and the preferential synthesis of these hydrolases have led to simple hypothetical relationships.
TL;DR: When a water-soluble polymer was added to the growth medium of Aspergillus niger, significant enhancement in the rates of cellular growth and amylase production were observed and the role of the polymer additive in the system was not due to its utilization as a source of energy or removal of toxic metabolic byproduct.
Abstract: When a water-soluble polymer ("Carbopol") was added to the growth medium of Aspergillus niger, significant enhancement in the rates of cellular growth and amylase production were observed. The role of the polymer additive in the system was not due to its utilization as a source of energy, neither to removal of toxic metabolic byproduct. Furthermore, it did not alter the respiratory quotient nor did it affect the overall enzyme system for respiration. Gross morphological changes from discrete pellets to filamentous growth was the only accountable parameter for yield enhancement.
TL;DR: The ability of 88 fungi, which had been obtained as high-potency strains for acid proteinase production, to produce a new type of acid carboxypeptidase (having on optimal pH of about 3 for hydrolysis of benzyloxycarbonyl-glutamyltyrosine) in surface koji culture was determined.
Abstract: The ability of 88 fungi, which had been obtained as high-potency strains for acid proteinase production, to produce a new type of acid carboxypeptidase (having on optimal pH of about 3 for hydrolysis of benzyloxycarbonyl-glutamyltyrosine) in surface koji culture was determined. Among the aspergilli, substantial amounts of this new acid carboxypeptidase were produced by Aspergillus saitoi, A. usamii, A. awamori, A. inuii, and A. niger. Maximum yields of acid carboxypeptidase per gram of substrate were obtained by submerged culture in a medium containing 0.9% defatted soybean and 0.6% wheat bran. However, the maximum enzyme concentration per milliliter was obtained with a medium containing 3% defatted soybean and 2% wheat bran. The terminal pH could be controlled by varying the concentrations of soybean oil meal and wheat bran. The maximum enzyme production was reached after 4 days or more at 30 C.
TL;DR: The enzymatic properties of intracellular myrosinase produced by Aspergillus niger AKU 3302 were investigated and this enzyme was neither activated nor inhibited by L-ascorbic acid.
Abstract: The enzymatic properties of intracellular myrosinase produced by Aspergillus niger AKU 3302 were investigated. Maximum activity occurred at pH 6.2, and the enzyme was stable in a pH range of 7.6 to 8.0 at 5°C for 24 hr. Optimum temperature was about 34°C. Enzyme activity was stimulated by copper (I), (II), manganese (II) and cobalt (II) and was inhibited by mercury (II) and stannous (II) ions. However, metal complexing agents and DFP had little effect, while PCMB was a strong inhibitor. In contrast to plant myrosinase, this enzyme was neither activated nor inhibited by L-ascorbic acid. Glucosides and δ-gluconolactone inhibited enzyme activity but sugars were ineffective. The Km value for sinigrin was 3.3×10-3M and that for p-nitrophenyl β-glucoside was 1.5×10-3M. The relation between fungous myrosinases and β-glucosidase is discussed in comparison to plant myrosinase.
TL;DR: Two proteinases of Aspergillus niger were purified 840- and 740-fold by (NH4)2SO4 precipitation Sephadex G-100, G-150 and G-200 gel chromatography and showed no cofactor requirements, was severely inhibited by HgCl2 and diisopropylphosphofluoridate and was also relatively inactive against low molecular weight synthetic substrates.
TL;DR: A cellulase preparation which exhibits the highest activity at a lower pH range, 2.3 to 2.5, was purified from a commercial cellul enzyme preparation from a culture filtrate of Asp.
Abstract: A cellulase preparation which exhibits the highest activity at a lower pH range, 2.3 to 2.5, was purified from a commercial cellulase preparation from a culture filtrate of Asp. niger and referred to as acid-cellulase.The purification involves ammonium sulfate fractionation, gel filtration and ion-exchange and adsorption chromatographies. The purified enzyme was revealed to be homogenous in ultracentrifugation and disc as well as ampholine electrophoreses and to be an acidic protein of which isoelectric point lied at pH 3.3. The sedimentation coefficient and molecular weight were determined to be 3.27 S and 46,000, respectively. The optical properties were also studied.
TL;DR: The activities of selected enzymes of the tricarboxylic acid and glyoxylate cycles were assayed at various points during the synchronous conidiation of Aspergillus niger and, in general, decreased in activity during conidiospore formation.
Abstract: The activities of selected enzymes of the tricarboxylic acid and glyoxylate cycles were assayed at various points during the synchronous conidiation of Aspergillus niger . With the exception of aconitase and malic dehydrogenase all the enzymes assayed were repressed during vegetative growth and early conidio-phore development. During vesicle and phialide formation all enzymes reached maximum activity and, in general, decreased in activity during conidiospore formation.
TL;DR: The present results indicate that a new pathway is operating in this strain of AspergiZZus niger, UBC 814 grown in the presence of phenylacetic acid.
TL;DR: The enzyme contained 378 residues of amino acids rich in acidic amino acids, 12 residues of glucosamine and 10 residues of arabinose per molecule, and N-terminus was not detected by DNP-method.
Abstract: Some properties of a purified acid-cellulase produced by Aspergillus niger were investigated. The acid-cellulase was stable at the pH range between 4.0 and 10.0 and exhibited the highest activity toward glycol cellulose at pH 2.5. The optimum temperature of activity was measured to be 50°C, while the enzyme was inactivated above 40°C by heating for 1 hr. Insoluble cellulose such as filter paper was difficult to be attacked by the enzyme. Mg2+ and Mn2+ ions inhibited the activity, while Co2+ ion caused a slight activation. The nitrogen content of the enzyme protein was determined to be 14.37%. The enzyme contained 378 residues of amino acids rich in acidic amino acids, 12 residues of glucosamine and 10 residues of arabinose per molecule. N-terminus was not detected by DNP-method.
01 Jan 1973
TL;DR: A model is described based on the existence of an intermetabolite accumulating in cells and acting as a growth-limiting factor for the prediction of continuous culture of the filamentous mold Aspergillus niger on the basis of batch culture data.
Abstract: A model is described based on the existence of an intermetabolite accumulating in cells and acting as a growth-limiting factor. This model is employed for the prediction of continuous culture of the filamentous mold Aspergillus niger on the basis of batch culture data.
TL;DR: Evidence for mono-oxygenase activity during the metabolism of thioethers by the fungus Aspergillus niger is presented and attempts to obtain selenoxides as microbial metabolic products are described.
Journal Article•
TL;DR: Anthranilate afforded protection against inhibition by o-phenanthroline, and was counteracted by ferric complexes such as ferric-ethylenediaminetetraacetic acid and ferric citrate.
Abstract: Evidence was obtained for the participation of iron in the double hydroxylation reaction catalyzed by anthranilate hydroxylase from Aspergillus niger (UBC 814). Omission of iron from the growth medium gave inactive preparations of anthranilate hydroxylase which could be reactivated by incubating the enzyme preparations with ferric citrate. The enzyme was susceptible to inhibition by metal chelating agents. The Ki for o-phenanthroline, which inhibited the enzyme activity non-competitively with respect to anthranilate, was calculated to be 0.9 mM. The inhibition by o-phenanthroline was counteracted by ferric complexes such as ferric-ethylenediaminetetraacetic acid and ferric citrate. Anthranilate afforded protection against inhibition by o-phenanthroline.
Journal Article•
01 Jan 1973-Zentralblatt für Bakteriologie, Parasitenkunde, Infektionskrankheiten und Hygiene. Zweite Naturwissenschaftliche Abteilung: Allgemeine, Landwirtschaftliche und Technische Mikrobiologie
TL;DR: Rhizoctonia solani seems to be the most affected fungus by the herbicides used, while Aspergillus niger and As pergillus flaves were completely resistant, except in rare cases.