Cell Wall Of Aspergillus Niger Research Articles

Three-dimensional porous Na4MnV(PO4)3 constructed by Aspergillus niger biological template as a high performance cathode for sodium ion batteries

The sodium super ion conductor (NASICON) structure materials have attracted extensive attention because of its open three-dimensional crystal network framework and fast sodium ion migration rate. However, the poor electronic conductivity due to the presence of phosphate groups and the consequent high cost have been a barrier to commercialization. In this work, Na4MnV(PO4)3 (NMVP) with three-dimensional porous structure is synthesized in situ using Aspergillus niger as a biological template (noted as NMVP/ANDC). The cell wall of Aspergillus niger is rich in hydroxyl groups, which can adsorb metal ions well, so that NMVP particles can be synthesized on Aspergillus niger without stacking and agglomeration. NMVP grows along Aspergillus niger mycelium has a spongy-like three-dimensional porous network structure, which helps the contact between active materials and electrolyte, reduces the migration distance of sodium ions, and improves the conductivity of active materials. Therefore, NMVP/ANDC has good rate performance and cycle stability. It can provide 109 mAh g−1 at 0.5 C and 79.6% capacity retention after 3000 cycles at 5 C. The biological template method is proposed in this paper opens up a simple way for the preparation of other three-dimensional porous network structural materials.

Development of high concentration hexavalent chromium resistant strain of Aspergillus niger for improved Cr6+ biosorption : Scanning Electron Microscopic and spectrophotometric studies

Hexavalent chromium (Cr 6+ ) is one of the most potent heavy metal pollutant released from various industries into water bodies. Most commonly used physico-chemical methods, for the removal of Cr 6+ from waste waters are inefficient, expensive and also produces unmanagable toxic sludge. Recent studies showed that biosorption, based on metal-biomass interaction can be an alternative to commonly employed methods for Cr 6+ removal from waste waters. Among the various biosorbent, bacteria, yeast, algae and fungi have potential for Cr 6+ biosorption. In this study, Bacillus circulans MTCC 3161, Saccharomyces cerevisiae and Aspergillus niger were screened for high Cr 6+ concentration tolerant strain isolation. It was found that, Bacillus circulans MTCC 3161 and Saccharomyces cerevisiae are resistant up to 800 ppm of initial Cr 6+ concentration present in the fermentation media, whereas, Aspergillus niger can resist up to 900 ppm of initial Cr 6+ concentration. Moreover, it was also found that Cr 6+ resistant Aspergillus niger have better biosorption potential (48% at 800 ppm) than that of Cr 6+ resistant Bacillus circulans MTCC 3161 and Saccharomyces cerevisiae (40% and 38% respectively at 800 ppm). Scanning Electron Microscopic studies of mycelia with spores of parent cells of Aspergillus niger, Cr 6+ resistant Aspergillus niger and Cr 6+ loaded Cr 6+ resistant Aspergillus niger revealed that exposure of parent Aspergillus niger to high Cr 6+ concentration induces morphological changes. Moreover, Cr 6+ loaded Cr 6+ resistant Aspergillus niger shows further changes in mycelial and hyphal morphology which occurs may be due to biosorption of Cr 6+ onto Cr 6+ resistant Aspergillus niger. Metal-biomass interaction was confirmed by Fourier Transform Infra Red (FTIR) spectroscopic study which also indicates the presence of hydroxyl, amine, amide, carbonyl or carboxyl groups, on cell wall of Aspergillus niger.

Spore cell wall components ofAspergillus niger elicit downy mildew disease resistance in pearl millet

Elicitors derived from the cell wall of fungi are shown to be active in eliciting resistance in plants against a wide range of pathogens. In the present study carbohydrate components from the autoclaved spore cell wall ofAspergillus niger were prepared as aqueous suspensions and tested for defense response in pearl millet (Pennisetum glaucum (L.) R.Br.) against the oomycetous downy mildew pathogenSclerospora graminicola (Sacc.) Schroet. The aqueous suspension derived from the spore cell wall ofA. niger was used as a seed soak treatment at concentrations of 0.25, 0.5, 1.0, 1.5 and 2.0 mg ml−1 for time intervals of 3, 6, 9 and 12 h. The concentration of 0.5 mg ml−1 for a 6 h soaking period offered 94% seed germination and seedling vigor index increased to 1526. The seed germination and the seedling vigor were significantly higher than the untreated check. Spore cell wall suspension as seed treatment at a concentration of 0.5 mg ml−1 required a 3-day time interval to provide 67% protection against downy mildew. Histological and biochemical studies were conducted to elucidate the mechanism of defense response in treated seedlings uponS. graminicola infection. Resistance host response was detected in the form of lignin and callose deposition in the epidermal cell wall of pearl millet seedlings, which is the site ofS. graminicola infection. A time course study showed rapid and localized deposition of lignin and callose in epidermal cell wall of carbohydrate components-treated pearl millet seedling coleoptiles. Increased levels of the defense-related enzyme peroxidase were detected in the treated seedlings. Peroxidase activity in elicitor-treated samples reached a peak at 8 h post-infection, which was 45% more than in their respective uninoculated control. Characterization of peroxidase isoforms by isoelectric focusing revealed 16 different isoforms, of which pI 6.8, 7.2 and 8.7 increased in elicitor-treated samples uponS. graminicola infection.

O 2− from elicitor-induced oxidative burst is necessary for triggering phenylalanine ammonia-lyase activation and catharanthine synthesis in Catharanthus roseus cell cultures

Elicitor, derived from the cell walls of Aspergillus niger, induced rapid generation of reactive oxygen intermediates (ROI), including superoxide anion (O 2 −) and hydrogen peroxide (H 2O 2), sequentially followed by phenylalanine ammonia-lyase (PAL) activation and catharanthine biosynthesis in Catharanthus roseus suspension cells. The elicitor-induced PAL activation and catharanthine biosynthesis were blocked by NAD(P)H oxidase inhibitor, diphenylene iodonium (DPI). O 2 − generated by the reaction of xanthine/xanthine oxidase (X/XO) triggered PAL activation and catharanthine biosynthesis of C. roseus cells in the absence of elicitor and reversed the inhibitory effect of DPI on elicitor-induced PAL activation and catharanthine biosynthesis. External application of H 2O 2 and catalase had no effect on PAL activity and catharanthine contents of C. roseus cells. The results demonstrated a causal relationship between elicitor-induced oxidative burst and PAL activation in C. roseus suspension cells and suggested a sequence of signaling events from ROI production to PAL activation and catharanthine synthesis. Within this sequence, O 2 − rather than H 2O 2 appeared to trigger the subsequent reactions.

Ultrasonic depolymerization of the chitin–glucan complex from Aspergillus niger and antimutagenic activity of its product

Sonication was effective for the depolymerization of carboxymethylated chitin–glucan complex (CM–CG) isolated from the cell wall of Aspergillus niger. After 10 min of sonication and subsequent gel filtration, two samples (CM–CG I and CM–CG II) with significantly distinct molecular weights ( 660 kDa and 19 kDa, respectively) and different nitrogen contents (3.02 and 1.69%) were obtained. CM–CG II with lower M w was also effective against cyclophosphamide mutagenicity by oral administration in mice.

Purification and Properties of Mycodextranase fromStreptomycessp. J-13-3

An enzyme hydrolyzing nigeran (alternating alpha-1,3- and alpha-1,4-linked glucan) was purified from the culture filtrate of Streptomyces sp. J-13-3, which lysed the cell wall of Aspergillus niger, by percipitation with ammonium sulfate and column chromatographies on DEAE-Sephadex A-50, CM-Sephadex C-50, chromatofocusing, and Sephadex G-100. The final preparation was homogenous in polyacrylamide gel electrophoresis (PAGE). The molecular weight of the enzyme was 68,000 by SDS-PAGE and gel filtration. The optimum pH and temperature for the enzyme activity were 6.0 and 50 degrees C, respectively. The enzyme was stable in the pH range from 6.0 to 8.0 and up to 50 degrees C. The enzyme activity was inhibited significantly by Hg+, Hg2+, and p-chloromercuribenzoic acid. The Km (mg/ml) for nigeran was 3.33. The enzyme specifically hydrolyzed nigeran into nigerose and nigeran tetrasaccharide by an endo-type of action, indicating it to be a mycodextranase (EC 3.2.1.61) that splits only the alpha-1,4-glucosidic linkages in nigeran.

Behaviour of the cell walls of Aspergillus niger during the autolytic phase of growth

Behaviour of the cell walls of Aspergillus niger during the autolytic phase of growth

Chemical structure of the galactomannan from the cell wall of Aspergillus niger.

The galactomannan of surface grown Aspergillus niger has been isolated by alkaline extraction of hyphal walls and characterized structurally. Its elution profile, from a column of Bio-Gel P-150, reveals a broad range of molecular sizes grouped into two fractions. Gas chromatographic and colorimetric analyses indicate that each fraction is composed of approximately equimolar quantities of galactose and mannose plus 12 to 14% glucose. Both have similar low optical rotations and contain acid labile galactose. Methylation, Smith degradation, acetolysis, reactivity with concanavalin A and beta-D-galactofuranosidase, plus digestionof galactose with D-galactose oxidase, were techniques employed to determine the polysaccharide's covalent structure. Results of these studies indicate that it is composed of a series of chains, 5 to 9 hexose units in length, connected by alpha1 leads to 6 bonds between mannopyranosyl moieties. The external portion of each chain consists of a galactose tri- or tetrasaccharide of the general structure Galf beta1 leads to 4 Galp(1-2) 1 leads to 4 Galp1 leads to. This segment is connected via a (1 leads to 2) linkage to the internal portion which is a di- to pentasaccharide of mannopyranosyl units joined in alpha1 leads to 2 glycoside linkage. Combination mild acid hydrolysis and methylation experiments indicate galactofuranosyl terminal units are attached only to galactose. The organization of glucose into the overall structure of the polymer has not been determined. Structural relationships of this polysaccharide to both fungal and yeast galactomannans are discussed.

Galactosaminogalactan from cell walls of Aspergillus niger

A new heteropolysaccharide has been isolated by alkaline extraction of hyphal walls of Aspergillus niger NRRL 326 grown in surface culture. Its composition by weight, as determined by paper and gas chromatography and colorimetric analyses, is 70% galactose, 20% galactosamine, 6% glucose, and 1% acetyl. Two independent experiments have been used to ascertain copolymer structure: permeation chromatography in 6 M guanidinium hydrochloride, with controlled-pore glass columns of two fractionation ranges, and nitrous acid deaminative cleavage of galactosaminogalactan followed by reduction of fragments with [3H]borohydride and gel filtration chromatography. One of the tritiated fragments is tentatively identified as the disaccharide derivative galactopyranosyl 2,5-anhydrotalitol, on the basis of chromatographic properties and by kinetics of its acid hydrolysis. Smith degradation, methylation, deamination, and optical rotation studies indicate that the galactosaminogalactan consists of a linear array of hexopyranosyl units joined almost exclusively by alpha-(1 leads to 4) linkages. Hexosaminyl moieties are distributed randomly along the chains, which have an average degree of polymerization of about 100. The possible significance of this macromolecule in hyphal structure is considered.

The characterization of a chitin-associated D-glucan from the cell walls of Aspergillus niger

Exhaustive extraction of the cell walls of Aspergillus niger with 10% NaOH solution leaves an alkali-resistant residue containing chitin and glucan as the major components. The glucan in this residue comprises 58.7% of the total cell wall glucan and was characterized by permethylation, and identification of the resulting O- methyl- D-glucoses obtained after hydrolysis by gas-liquid chromagtography and mass spectrometry of the derived partially acetylated, partially methylated, [1- 2H]alditols. The glucan was separated from the chitin by acetylation of the alkali-resistance material, a procedure which separates a large portion of the total glucan as a chloroformsoluble acetate, abd by treatment of the alkali-insoluble residue with nitrous acid, a procedure which was found to render the complex soluble in dimethylsulfoxide and amenable, therefore, to permethylation. The data collected suggests that the preparation is an essentially linear glucan containing 85–95% 1 → 3 linkages and 10–15% 1 → 4 linkages. An analysis of the glycosidic linkages using NMR spectroscopy indicate that both α and β linkages are present in the ratio of 4:1. 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.

The parasitism of the mould Penicillium purpurogenum on Aspergillus niger. 3. The determination of the part of some enzymes of Penicillium purpurogenum in the mycelium lysis of the mould Aspergillus niger.

The enzymatic composition of thePenicillium purpurogenum preparation cultivated on Czapek medium (PCz), and on the medium prepared from the mycelium of the mouldAspergillus niger (PAn), has been followed, causing the lysis ofAspergillus niger cell walls.Penicillium purpurogenum forms cellulolytic enzymes, enabling the utilization of cellulose as a sole carbon source.In vitro experiments with enzymatic preparations (PAn) indicated a rapid decrease inviscosity of carboxymethylcellulose at a negligible increase in reduction. The enzymatic preparations (PCz), causing also cell wall lysis inAspergillus niger, were however cellulolytically inactive, their presence in the systems causing their lysis is therefore not assumed.Penicillium purpurogenum also forms amylases, in cell walls ofAspergillus niger however no corresponding substrate is present. Proteases are synthetized only adaptively, and the results indicate that even lipases, also present in the substrate, are not a part of the lytic system. Chitinases are of the constitutive type, and are presumably a part of the enzymatic complex causing cell lysis. The main factor is anyhow an enzyme, or an enzymatic system, which is subjected to further investigation.

The partial acid hydrolysis of a highly dextrorotatory fragment of the cell wall of Aspergillus niger. Isolation of the alpha-(1-3)-linked dextrin series.

1. A highly dextrorotatory polysaccharide (alpha(D)+232 degrees in n-sodium hydroxide), previously isolated as a fragment of Aspergillus niger cell walls, was prepared from whole mycelium and subjected to partial acid hydrolysis. 2. Fractionation of the hydrolysate on a charcoal column with a linear gradient of ethanol yielded a series of oligosaccharides. The disaccharide member was shown to be nigerose (3-O-alpha-d-glucopyranosyl-alpha-d-glucopyranose), although a small proportion of the disaccharide peak (10%) was present as maltose despite the fact that all the nigeran had been removed from the starting material. 3. The oligosaccharides forming the main peaks from the column were shown to be members of a polymer-homologous series (nigerodextrins) by (a) the relationship between the logarithm of their chromatographic mobility and degree of polymerization, (b) obeying the Freudenberg relationship, and (c) partial acid hydrolysis.

The composition of the cell wall of Aspergillus niger.

1. The cell-wall composition of Aspergillus niger has been investigated. Analysis shows the presence of six sugars, glucose, galactose, mannose, arabinose, glucosamine and galactosamine, all in the d-configuration, except that a small amount of l-galactose may be present. Sixteen common amino acids are also present. 2. The wall consists chiefly of neutral carbohydrate (73-83%) and hexosamine (9-13%), with smaller amounts of lipid (2-7%), protein (0.5-2.5%) and phosphorus (less than 0.1%). The acetyl content (3.0-3.4%) corresponds to 1.0mole/mole of hexosamine nitrogen. 3. A fractionation of the cell-wall complex was achieved, with or without a preliminary phenol extraction, by using n-sodium hydroxide. Though this caused some degradation, 30-60% of the wall could be solubilized (depending on the preparation). Analyses on several fractions suggest that fractionation procedures bring about some separation of components although not in a clear-cut fashion. 4. Cell-wall preparations were shown to yield a fraction having [alpha](D) approx. +240 degrees (in n-sodium hydroxide) and consisting largely of glucose. This was separated into two subfractions, one of which had [alpha](D)+281 degrees (in n-sodium hydroxide) and had properties resembling the polysaccharide nigeran; the other had [alpha](D) +231 degrees (in n-sodium hydroxide). It is suggested that nigeran is a cell-wall component.