Soil Filamentous Fungi Research Articles

Filamentous Soil Fungi from Ny-Ålesund, Spitsbergen, and Screening for Extracellular Enzymes

Soil filamentous fungi from Ny-Alesund, Spitsbergen, were studied. A total of 30 fungal isolates were identified by morpho-taxonomy, and the identity of some morpho-taxonomically complex isolates was authenticated by ITS1-5.8S and ITS2 rDNA domain sequence similarity. The isolates belonged to 19 species under 14 genera ( Acremonium , Arthrinium , Aspergillus , Cladosporium , Corynespora , Emericella , Geomyces , Mortierella , Mucor , Myrothecium , Penicillium , Phialophora , Preussia , Xylaria ). To the best of our knowledge, Acremonium roseolum , Aspergillus aculeatus , Emericella nidulans , and Preussia sp. are the first northernmost records from Arctic soils. The viable fungal count in different soil samples varied from 0.5 • 10 4 to 2.0 • 10 5 g -1 . Species richness in different soil samples was also calculated. Mortierella was one of the most dominant genera in Arctic soils. A temperature tolerance study was carried out for all the isolates, and representative species were screened for their extracellular enzyme activity (amylase, cellulase, phosphatase, and pectinase) at 4˚C and 20˚C. Among the 30 isolates, seven showed cellulolytic activity, two were phosphate solubilizers, three had amylolytic activity, and only one showed pectinolytic activity on solid media. CMCase (β1, 4-endoglucanase) activity was quantified in seven isolates that exhibited positive activity during preliminary screening. The records of enzyme activity for amylases, pectinases, and cellulases are the first from the fungi of Spitsbergen. The present study indicates the dominance in Ny-Alesund of cellulolytic strains, which may serve as potent decomposers in Arctic tundra. These isolates may be used to facilitate the mineralization of cellulolytic wastes generated by human activities in colder hilly areas across the world, including the Himalayas in India.

Interaction of soil filamentous fungi affects needle composition and nutrition of Norway spruce seedlings

The effects of the interactions of soil filamentous fungi (including saprotrophic, mycorrhizal and endophytic fungi) on several morphological and physiological parameters of Norway spruce seedlings [Picea abies (L.) Karst.] were studied in a pot experiment. Both mycorrhizal variants (Hebeloma bryogenes and Cadophora finlandica) were slightly inhibited with respect to the accumulation of aboveground biomass. However, these variants exhibited significantly improved foliar content of N, P, and Ca (H. bryogenes variant also K), compared to controls. The presence of the saprotrophic fungus Setulipes androsaceus attenuated the positive effect of mycorrhizal fungi on Ca, P, and K content, but did not reduce the positive effect of mycorrhizal fungi on the N content of the seedlings’ needles. Raman spectroscopy revealed that both mycorrhizal fungi increased the foliar content of carotenoids compared to the controls, but the effect diminished in the presence of S. androsaceus. In contrast, in the presence of the dark septate endophyte Phialocephala fortinii, needles exhibited significantly higher wax content and lower carotenoid content compared to the mycorrhizal variants. The presence of the saprotrophic isolate Serpula himantoides resulted in a decrease in needle waxes in comparison to controls. The needles’ carotenoid concentration was positively correlated with the levels of needle nutrients (N, P, K, Ca, Mg), while correlation of needle nutrients (N, P) with the needle wax concentration was negative. We conclude that not only individual fungi but also their interactions profoundly affect the nutrition and needle composition of Norway spruce seedlings.

Cathepsin B Inhibitory Tetraene Lactones from the Fungus Talaromyces wortmannii

Abstractmagnified imageWortmannilactones E–H (1–4), four new cathepsin B inhibitors, were produced and isolated from the culture of the soil filamentous fungus Talaromyces wortmannii. Their structures and relative configurations were elucidated on the basis of 1D‐ and 2D‐NMR techniques, three of them (1, 2, and 4) posses an oxabicyclo[2.2.1]heptane moiety. Compounds 1–4 showed inhibitory activities against cathepsin B with IC50 values of 4.3, 6.5, 13.0, and 6.0 μM, respectively.

Biodegradation of Electrospun Poly-(?-caprolactone) Non-woven Fabrics by Pure-Cultured Soil Filamentous Fungi

The biodegradation of electrospun nano-fibers of poly(ɛ-caprolactone) (PCL) was initially investigated with respect to the environmental application of PCL non-woven fabrics, using pure-cultured soil filamentous fungi, Aspergillus oryzae, Penicillium caseicolum, P. citrinum, Mucor sp., Rhizopus sp., Curvularia sp., and Cladosporium sp. Three kinds of non-woven PCL fabrics with different mean fiber diameters (330, 360, and 510 nm) were prepared by changing the viscosities of the pre-spun PCL solutions (150, 210, and 310 cPs, respectively). All of the pure-line soil filamentous fungi tested grew on the two fiber materials. Electron microscopy was used to observe the biodegradation processes revealing remarkable growth of two fungi, Rhizopus sp. and Mucor sp., along with the accompanying collapse of the nano-fiber matrices. In the biochemical oxygen demand (BOD) test, the biodegradation of the 330 nm PCL nano-fibers by Rhizopus sp. and Mucor sp. exceeded 20 and 30% carbon dioxide generation, respectively. The biodegradability of the PCL non-woven fabrics decreased with the mean fiber diameter and the 330 nm PCL nano-fiber that was made from 150 cPs solution (concentration, 7 wt%) exhibited the highest biodegradability. These results might offer some clues for the applications of the PCL non-woven fabrics having the controlled biodegradability in the environmental uses.

Electrospun Non‐Woven Fabrics of Poly(ϵ‐caprolactone) and Their Biodegradation by Pure Cultures of Soil Filamentous Fungi

AbstractThe biodegradation of electrospun nano‐fibers of poly(ϵ‐caprolactone) was firstly investigated, using pure‐cultured soil filamentous fungi. In the biochemical oxygen demand test, the biodegradation of the nano‐fiber exceeded 20‐30% carbon dioxide generation. The biodegradabilities decrease with increase of the mean fiber diameter.

Variations of lignocellulosic activities in dual cultures of Pleurotus ostreatus and Trichoderma longibrachiatum on unsterilized wheat straw

Trichoderma spp., soil filamentous fungi, are antagonists that can cause great losses in mushroom production. We have investigated the influence of T. longibrachiatum on the production of lignocellulolytic enzymes by Pleurotus ostreatus during its vegetative growth on a straw-based cultivation substrate that either had been sterilized, pasteurized or not heat treated. The variations in the lignocellulolytic activities and the electrophoretic patterns in single and dual cultures were used as a tool for perturbation assessment. The various heat treatments of the wheat straw before inoculation affected both the bacterial populations and the abilities of T. longibrachiatum and P. ostreatus to colonize the substrate and to produce extracellar lignocellulolytic enzymes. Interactions between T. longibrachiatum and the microflora of the substrate led to a great decrease of hydrolytic activities due to reduced colonization of the substrate. Pleurotus ostreatus also was affected but it was less sensitive than T. longibrachiatum. As a consequence, in dual cultures with P. ostreatus, the competitive ability of T. longibrachiatum was reduced by bacteria in the substrates. The presence of total microflora or thermotolerant microflora increased the production of phenoloxidase activities by P. ostreatus, despite reduced colonization of the substrate. This contributed to the improvement of the competitive ability of P. ostreatus in the pasteurized substrate. Furthermore, a direct effect of bacteria on T. longibrachiatum also was observed. In sterilized substrate, both laccase and Mn-peroxydase activities were increased dramatically in dual cultures due to a faster production of a laccase isoform, which was stimulated by T. longibrachiatum.

Fungal Decomposition of Natural Aromatic Structures and Xenobiotics: A Review

The review deals with transformation of natural and synthetic aromatic compounds by fungi (causative agents of white rot, brown rot, and soft rot, as well as soil filamentous fungi). Major enzyme types involved in the transformation of lignin and aromatic xenobiotics are discussed, with emphasis on activity regulation under the conditions of secondary metabolism and oxidative stress. Coupling of systems degrading polysaccharides and lignin and non-phenolic lignin structures (without the involvement of lignin peroxidase) is analyzed, together with nonenzymatic mechanisms involving lipoperoxide free radicals, cation radicals, quinoid mediators, or transition metal ions. Metabolic pathways resulting in the formation of aromatic and haloaromatic compounds in fungi are described. Consideration is given to the mechanisms of fungal adaptation to aromatic xenobiotics.

Unusual fatty acid composition of cerebrosides from the filamentous soil fungus Mortierella alpina

The cerebrosides produced by the soil filamentous fungus Mortierella alpina strain KG-1/95 account for about 13% of the total polar lipids extractable from lyophilised cells with chloroform/methanol mixtures. By means of 1H NMR and 13C NMR spectroscopy, matrix-assisted laser-desorption ionisation mass spectrometry, and chemical degradation experiment, they have been shown to be 1- O-β- d-glucopyranosyl-2- N-(2′- d-hydroxyalkanoyl)-9-methylsphinga-4( E),8( E)-dienines, the fatty acid composition of which is unusual and consists of 2-hydroxytridecanoic (4%), 2-hydroxytetradecanoic (60%), 2-hydroxypentadecanoic (20%), and 2-hydroxyhexadecanoic (16%) acids.

Photoresponsive Peptide and Polypeptide Systems, 14. Biodegradation of Photocrosslinkable Copolypeptide Hydrogels ContainingL-Ornithine andδ-7-Coumaryloxyacetyl-L-ornithine Residues

Copoly[Orn/Orn(Cou)] containing δ-7-coumaryloxyacetyl-L-ornithine [Orn(Cou)] and L-ornithine (Orn) residues was synthesized by the N-carboxyanhydride method. When aqueous solutions of copoly[Orn/Orn(Cou)] containing 5–10 mol-% of Orn(Cou) are irradiated, the photoinduced dimerization reaction between coumarin moieties in the side chains proceeds slowly, and after 24 h the solutions become transparent hydrogels. The gels exhibit solvent-induced reversible expansion and contraction behavior in both water and ethanol. The biodegradation of the hydrogels by proteolytic enzymes and soil filamentous fungi is investigated using photocrosslinked copoly[Orn/Orn(Cou)] gels. The copoly[Orn89/Orn(Cou)11] gel is degradable by protease type XXIII, but not by trypsin. In the biochemical oxygen demand test, the order of the microbial biodegradation (%) was Rhizopus sp. (92%) > A. oryzae (38%) > P. caseicolum (18%) > P. citrinum (11%) > Cladosporium sp. (6%). The order for the copoly[Orn89/Orn(Cou)11] hydrogel is inverse to that for a polylysine/glutaraldehyde gel. These results suggest that the biodegradabilities of photocrosslinked hydrogels can be controlled by the monomer ratio of Orn, Orn(Cou) and lysine (Lys) in the parent copoly(amino acid)s of the photocrosslinked hydrogels.

Two unusual glycerophospholipids from a filamentous fungus, Absidia corymbifera

The chloroform–methanol extractable lipids of the soil filamentous fungus Absidia corymbifera VKMF-965 account for about 20% by weight of dry cells and are composed of low-polarity constituents (about 75% of the total lipids), such as triacylglycerols (mainly), diacylglycerols, sterols and free fatty acids, as well as of glycolipids (about 3%) and phospholipids. The last consist largely of components common to the fungal lipids, namely, phosphatidylethanolamine (38% of the total phospholipids), phosphatidyl- myo-inositol (16%), diphosphatidylglycerol (12%), phosphatidylcholine (7%), phosphatidic acid (6%) and phosphatidylglycerol (3%), and two unusual phospholipids, PL1 (6%) and PL2 (9%). Based on the infrared (IR), 1H-nuclear magnetic resonance (NMR), 13C-NMR and mass spectra along with the results of degradation experiment, these two phospholipids have been established to be 1,2-diacyl- sn-glycero-3-phospho( N-acetylethanolamine), or N-acetyl phosphatidylethanolamine, and 1,2-diacyl- sn-glycero-3-phospho( N-ethoxycarbonyl-ethanolamine), respectively. These structures have been confirmed by preparing similar phospholipids from the phosphatidylethanolamine isolated from the same fungus and correlating their chromatographic behaviour, IR and 1H-NMR spectra with those of PL1 and PL2. So far N-acetyl phosphatidylethanolamine has been detected only in cattle and human brains and a human placenta but its structure was not rigorously proved. PL2 is a novel lipid; to our knowledge no natural phospholipid with an urethane group has yet been found. The main fatty acids of both the phospholipids are n-hexadecanoic, octadecanoic and octadecadienoic ones; PL2 contains in addition a considerable amount of octadecatrienoic acid with its greater portion located at the sn-1 position.

Biodegradation of Chitosan-Gellan and Poly(L-lysine)-Gellan Polyion Complex Fibers by Pure Cultures of Soil Filamentous Fungi

The degradation of two kinds of polyion complex (PIC) fibers, chitosan-gellan (CGF), and poly(L-lysine)-gellan (LGF) fibers, by seven species of soil filamentous fungi has been investigated. All of the pure-line soil filamentous fungi, Aspergillus oryzae, Penicillium caseicolum, P. citrinum, Mucor sp., Rhizopus sp., Curvularia sp., and Cladosporium sp. grew on the two fiber materials. Microscopic observation of the biodegradation processes revealed that P. caseicolum on the CGF and LGF grew, along with the accompanying collapse of the fiber matrices. In the biochemical oxygen-demand (BOD) test, the biodegradation of the LGF by P. caseicolum and Curvularia sp. exceeded 97% carbon dioxide generation and the biodegradation of the CGF by A. oryzae was 59%. These results might offer some clues to the applications of the PIC fibers as environmentally biodegradable materials.

Photoresponsive Peptide and Polypeptide Systems. 13. Photoinduced Cross-Linked Gel and Biodegradation Properties of Copoly(l-lysine) Containing ε-7-Coumaryloxyacetyl-l-lysine Residues

Copoly[LysLys(Cou)] containing e-7-coumaryloxyacetyl-l-lysine [Lys(Cou)] residues were synthesized by the N-carboxyanhydride method. When the aqueous solutions of copoly[LysLys(Cou)] containing 5−10 mol % of Lys(Cou) are irradiated by light, the photo-cross-linking reaction proceeds slowly between coumarin moieties in the side chains to give a cis head-to-head cyclocoumarin, and after 6−24 h the solutions become transparent hydrogels. The gels exhibit solvent-induced reversible expansion and contraction behavior in water and in ethanol. The biodegradation of the hydrogels by some proteolytic enzymes and soil filamentous fungi has been investigated using photo-cross-linked copoly[LysLys(Cou)] gels. The photo-cross-linked copoly[Lys90-95Lys(Cou)10-5] gels are degradable by trypsin and protease type XXIII or two microorganisms, Aspergillus oryzae and Penicillium citrinum, suggesting potential for a controlled biodegradation by the different cross-linking densities in the gel matrixes upon the controlled irra...

Biodegradation of ornithine-containing polylysine hydrogels

The degradation of the cross-linked cationic poly(amino acid)-glutaraldehyde (GA) hydrogels by two kinds of proteolytic enzymes, trypsin and Aspergillus Protease Type XXIII, and by seven species of soil filamentous fungi has been investigated using homo- and copolypeptides of lysine (Lys) and ornithine (Orn). Trypsin degraded the hydrogels prepared from poly(Lys) and copoly(Lys Orn)s but not poly(Orn), while Aspergillus protease degraded all of them. Degradation time of hydrogels by the two proteases became longer with increasing Orn content in the gel. Seven species of soil filamentous fungi were cultured with hydrogels on Czapeck medium to evaluate the degree of microbial degradation of the hydrogels, and the three species of the fungi, Aspergillus oryzae, Penicillium citrinum and Curvularia sp., were grown in culture with an accompanying degradation of the gel matrix, while the other four species, Mucor sp., Rhizopus sp., Cladosporium sp., and Trichoderma sp., were not. The degree of degradation of gel matrix with growth of the three fungi became lower with increasing Orn content in the gel matrix. The results might offer some clues to the applications for the controlled biodegradation of cationic poly(amino acid) hydrogel by introduction of Orn, suggesting that unnatural amino acid resists hydrolysis by proteases or microorganisms.

Filamentous soil fungi and unidentified bacteria in drinking water from wells and water mains near Bratislava

The occurence of filamentous fungi in 294 samples of drinking water taken from wells and taps near Bratislava was studied. Fungal contaminants were found in 192 samples (44%). 39 genera and 64 species of soil filamentous fungi were identified by routine isolation and cultivation methods. Most of them belong to the Deuteromycetes. In the course of fungal cultivation in Czapek-Dox agar supplemented with 20 mg · l -1 tetracycline, colonies of unknown yellow coloured bacteria were observed.