Individual patterns of immediate skin reactivity to mold extracts.

One hundred atopic patients were skin tested intradermally over a 2-year period with 30 different mold extracts. Subjects were monitored for immediate reactions. Data suggest that to evaluate mold sensitivity in atopic patients one must use multiple mold extracts.

Structure and absolute configuration of pyrophen, a novel pryrone derivative of L-phenylalanine from Aspergillus niger.

Pyrophen, a novel 4-methoxy-2-pyrone derivative of L-phenylalanine isolated from cultures of Aspergillus niger, crystallizes in the orthorhombic space group P2(1)2(1)2(1), with a = 8.918(1), b = 9.199(3), and c = 18.092(4) A. The structure was solved by direct methods and the absolute configuration assigned by the Bijvoet method. Refinement gave R = 0.045 and S = 1.78 for 1677 reflections with I greater than 3 sigma (I). Though numerous other pyrone natural products are known, including other products of A. niger, this is the first report of an amino acid-pyrone derivative.

Identification of carboxylic acid residues in glucoamylase G2 from Aspergillus niger that participate in catalysis and substrate binding.

Functionally important carboxyl groups in glucoamylase G2 from Aspergillus niger were identified using a differential labelling approach which involved modification of the acarbose-inhibited enzyme with 1-ethyl-3-(4-azonia-4,4-dimethylpentyl)carbodiimide (EAC) and inactivation by [3H]EAC following removal of acarbose. Subsequent sequence localization of the substituted acidic residues was facilitated by specific phenylthiohydantoins. The acid cluster Asp176, Glu179 and Glu180 reacted exclusively with [3H]EAC, while Asp112, Asp153, Glu259 and Glu389 had incorporated both [3H]EAC and EAC. It is conceivable that one or two of the [3H]EAC-labelled side chains act in catalysis while the other fully protected residue(s) participates in substrate binding probably together with the partially protected ones. Twelve carboxyl groups that reacted with EAC in the enzyme-acarbose complex were also identified. Asp176, Glu179 and Glu180 are all invariant in fungal glucoamylases. Glu180 was tentatively identified as a catalytic group on the basis of sequence alignments to catalytic regions in isomaltase and alpha-amylase. The partially radiolabelled Asp112 corresponds in Taka-amylase A to Tyr75 situated in a substrate binding loop at a distance from the site of cleavage. A possible correlation between carbodiimide modification of an essential carboxyl group and its role in the glucoamylase catalysis is discussed.

Element localisation and distribution in the fungi Aureobasidium pullulans and Aspergillus niger, measured using the Oxford scanning proton microprobe.

The distribution and relative concentrations of essential elements were determined in germ tubes of Aureobasidium pullulans and hyphae of Aspergillus niger using the Oxford scanning proton microprobe. In both fungi, K, P and S were the major constituents, with Ca, Na and trace metals like Cu, Mn, Fe and Zn present at lower levels. In A. pullulans, elements were not distributed uniformly throughout the cells and, in general, the highest elemental concentrations occurred at the tip and in the older parts of the germ tube, particularly where there was yeast-like cell or branch development. In A. niger, elemental distribution was more uniform and there was a general gradient of increasing concentration away from the hyphal tip followed by a drop in levels in older regions. The scanning proton microprobe appears to have considerable potential for the investigation of fungal differentiation and morphogenesis.

Lipid profiles of conidia of Aspergillus niger and a fatty acid auxotroph.

Conidial lipids of the wild-type (V35) Aspergillus niger and its unsaturated fatty acid auxotroph (UFA2) were compared. The wild type contained lower levels (7.6%) of phospholipids and higher levels (28.4%) of glycolipids than the mutant (16.5 and 22.2%, respectively). Oleic (33.4%), linoleic (22.5%), palmitic (12.8%), stearic (7.4%), and linolenic (6.2%) were the main fatty acids of the wild type (V35). The mutant grew only in the presence of unsaturated fatty acid having at least one delta 9cis double bond, and its conidial fatty acid profile was influenced by the exogenous acid. Analyses of the fatty acids of UFA2 grown in the presence of different fatty acid supplements support the original view that the mutant is defective in delta 9-desaturase activity.

Evidence that the mechanisms of fungitoxicity of 8-quinolinol and its bischelate with copper(II) are different.

The copper(II) contents of the growth media, Sabouraud dextrose and Czapek-Dox broths, and of the spore inocula of Aspergillus niger (ATCC 1004), Aspergillus oryzae (ATCC 1011), Trichoderma viride (ATCC 8678), and Myrothecium verrucaria (ATCC 9095) were determined by atomic absorption spectrophotometry in a graphite furnace. The test systems composed of Sabouraud dextrose broth and spore inocula of the four fungi contained only a little over 3% of the copper(II) required to form a minimal inhibitory concentration of bis(8-quinolinolato)copper(II). The test system of Czapek-Dox broth and A. oryzae contained slightly less than 65% of the copper(II) required to form a minimal inhibitory concentration of the bischelate of 8-quinolinol with copper(II). When the minimal inhibitory concentrations of 8-quinolinol and bis(8-quinolinolato)copper(II) were added simultaneously to the test system of Czapek-Dox broth and A. oryzae, 10% of the combined mixture of toxicants caused complete inhibition of growth indicating synergism between the toxicants. These results together with the observation that alpha-lipoic acid as well as small aliphatic thiol-containing compounds (cysteine, glutathione, dithioerythritol, and dithiothreitol) reversed the toxicity of 8-quinolinol but not the toxicity of bis(8-quinolinolato)copper(II) led to the conclusion that the mechanisms of fungitoxicity of both toxicants are different.

Lipid profiles of Aspergillus niger and its unsaturated fatty acid auxotroph, UFA2.

A comparative study of the mycelial lipid composition of a wild strain (V35) and one unsaturated fatty acid auxotroph (UFA2) of Aspergillus niger has been performed. The lipid composition of both strains are qualitatively the same but quantitatively different. All the strains contain the following phospholipids: cardiolipin, phosphatidylethanolamine, phosphatidylcholine, lysophosphatidylethanolamine, lysophosphatidylcholine, and phosphatidylserine; and triglycerides, diglycerides, monoglycerides, ergosterol, and sterol esters as the neutral lipids; mono- and di-galactosyl diglyceride as the major glycolipids along with small amounts of the corresponding mannose analogs. Phosphatidylethanolamine and phosphatidylcholine constitute the bulk of the phospholipids. The mutant (UFA2) contains a higher level of glycerides and lower levels of sterol (both free and esterified form), phospholipids, and glycolipids than the wild type. Aspergillus niger contains C16 to C18 saturated and unsaturated fatty acids. Small amounts of long-chain (C20 to C24) and short-chain (C10 to C14) saturated and unsaturated acids are also present. Linoleic, oleic, and palmitic are the major acids, stearic and linolenic acids being minor ones. UFA2 grows only in the presence of unsaturated fatty acid (C16 or C18) and accumulates a higher concentration of supplemented acid which influences its fatty acid profile.

[Fatty acid composition of the lipids in fungi of the genus Aspergillus developing on mineral media with different carbon sources]. / Zhirnokislotnyi sostav lipidov gribov roda Aspergillus pri razvitii ikh na mineral'nykh sredakh s razlichnymi istochnikami ugleroda.

This work was aimed at studying the effect of different carbon sources in the composition of mineral media on the growth of fungi belonging to the Aspergillus genus and on the fatty acid composition of their lipids. A chemically-defined medium with glucose was shown to be optimal for the growth of 18 Aspergillus strains and for the synthesis of lipids by them. The fatty acid composition of lipids was studied when the fungi grew in media with different carbon sources. The lipids were shown to contain saturated and unsaturated fatty acids with the prevalence of oleic, linoleic and linolenic acids.

A thiol inhibitor produced by Aspergillus niger.

A low molecular weight inhibitor of the thiol proteases papain and bromelain has been identified and partially purified from the culture filtrates of Aspergillus niger. Further studies have shown that this inhibitor reacts with compounds containing a free thiol group and as such it is capable of inhibiting other enzymes that contain a functional thiol group at their active site.

Chelating, film-forming, and coagulating ability of the chitosan-glucan complex from Aspergillus niger industrial wastes.

Waste mycelia of Aspergillus niger from a citric acid production plant are simply treated with boiling 30-40% NaOH aqueous solutions for 4-6 hr to obtain the insoluble chitosan-glucan complex whose infrared, ESR, and x-ray diffraction spectra are reported. A number of transition- and post-transition-metal ions are chelated and collected by chitosan-glucan with higher yields than by animal chitosan. Immediate flocculation occurs upon mixing chitosan-glucan dispersions with alginate and polymolybdate solutions. Membranes are also obtained from chitosan-glucan dispersions in acetic acid or in chloral and dimethyl formamide mixtures.

Pyridine nucleotide levels and ratios in Aspergillus niger.

A reliable method for the extraction and assay of pyridine nucleotides (NAD, NADH, NADP, and NADPH) in filamentous fungi is presented. The method is applied to a study of the physiology of citric acid accumulation by Aspergillus niger. The measurement of "catabolic reduction change" (NADH/(NAD + NADH)) and "anabolic reduction charge" (NADPH/(NADP + NADPH)) as a means of characterizing the metabolic state is discussed.

[Paramagnetic properties of the conidial pigments of Aspergillus niger and Penicillium notatum fungi isolated from the mesosphere]. / Paramagnitnye svoistva konidial'nykh pigmentov gribov Aspergillus niger i Penicillium notatum, vydelennykh iz mezosfery.

The conidia of Aspergillus niger and Penicillium notatum detected in the upper atmospheric layers of the Earth (58--77 km) were found to contain stable paramagnetic centres (PMC) at concentrations of 0.2 X 10(18) and 1.6 X 10(18) per gram of dry biomass, respectively. Aspergillin, the black pigment of Asp. niger, was shown to have (0.1--0.6) X 10(18) PMC per gram of dry substance (depending on the fraction). Stable paramagnetism of the conidial pigments with respect to their active protecting action in vivo is discussed on the basis of these data.

13C nuclear magnetic resonance spectra of fungal melanins.

The 13C resonance spectra of fungal melanins from Aspergillus niger, Eurotium echinolatum, and Stachybotrys chartarum are reported. The spectra were taken in 5% W/W solution of the substances in 0.1 N NaOD in D2O using the Fourier-transform-technique. The spectra and possible assignments of the bands are discussed. The similarities of these spectra to those of soil humic acids are unexpectedly small.

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.

Isolation of isoflavones inhibiting DOPA decarboxylase from fungi and streptomyces.

By screening of culture filtrates of fungi and streptomyces for activity in inhibit dopa decarboxylase the following isoflavone compounds were obtained: psi-tectorigenen (I), genistein (II), orobol (IV), 8-hydroxygenistein (V) and a new compound (III). III was elucidated to be 3', 4', 5, 7-tetrahydroxy-8methoxy isoflavone. Among these isoflavones, IV and III showed the strongest activity in inhibiting dopa decarboxylase. All these isoflavones also inhibited histidine decarboxylase and catechol-O-methyltrasnferase. Activities of these compounds to inhibit tyrosine hydroxylase and dopamine beta-hydroxylase were examined. Orobol which showed no or only slight inhibition of tyrosine hydroxylase and dopamine beta-hydroxylase exhibited a significant hypotensive effect on spontaneously hypertensive rats.