Gerhard Gramss - Academia.edu (original) (raw)

Papers by Gerhard Gramss

Mycological Research, 1998

Microbial Ecology, May 28, 2008

Non-symbiotic microorganisms engineered or expensively selected to degrade xenobiotic hydrocarbon... more Non-symbiotic microorganisms engineered or expensively selected to degrade xenobiotic hydrocarbons or modify heavy-metal uptake of plants in soil remediations die back after their introduction into the target soils. Mycelia of saprobic basidiomycetes were therefore inoculated into soil samples of 1 l in glass vessels to record mycelial growth and reproduction in the immediate rhizosphere of up to 11 herbaceous plant species, or to study their responses to the separate volatiles from whole plant swards or their root balls whose emanations had been collected in 1.5-l plastic bags fixed to the glass vessels. Excess CO 2 was controlled with NaOH solution. Volatiles from root balls of parsley and pea but not wheat, from unplanted soils, from the funguspermeated, unplanted substrate soil itself, and from the rooting soil of whole wheat sward increased mycelial densities in Clitocybe sp. more than in Agaricus macrocarpus and indicated thus a higher nutrient state of the mycelia. Organic volatiles proved therefore to be a significant carbon source for certain basidiomycetes in poor natural soils. The contemporary decline in the number of basidiocarp initials to 0 to 36% in both fungi relative to the unplanted and aerated controls was caused by volatiles from rooted and unplanted soil and pointed thus to their ecological role as antibiotics, fumigants, toxins, and hormonal compounds. Aqueous extracts from root balls of wheat stimulated mycelial density and fruiting in A. macrocarpus contemporarily because of their contents in soil-derived macronutrients. They suppressed once more fruiting in the more sensitive Clitocybe sp. by active agents in the aqueous phase. Within plant rhizospheres, densities of Clitocybe sp. mycelia were stimulated in the presence of alfalfa, carrot, red clover, ryegrass, and spinach, whereas those of A. macrocarpus were halved by 7 of 10 plant species including alfalfa, red clover, ryegrass, and spinach. Mycelia of A. macrocarpus may thereby have responded to differences in concentration and composition of volatile compounds. The contemporary repression of fruiting in both fungi and in nearly all treatments was not due to plant competition for macronutrients. Mycelia of basidiomycetes over-compensated for losses in macronutrients to the plant by decomposing soil matrix constituents. It is concluded that organic volatiles emitted by several plant organs and natural soils improved the nutritional state of A. macrocarpus and Clitocybe sp. but not of Agaricus bisporus mycelia and could therefore help establish certain ground fungi in the field. The contemporary and general suppression of fruiting by constituents of the gaseous (and liquid) phase in all fungi examined suggests interference with basic physiological processes and recommends an urgent re-examination of the degradative ability of basidiomycetes in the presence of volatiles.

J Basic Microb, 2005

Factors influencing water solubility and plant availability of mineral compounds in the tripartit... more Factors influencing water solubility and plant availability of mineral compounds in the tripartite fairy rings of Marasmius oreades (BOLT.: FR.) FR.

Plant Growth Regulation, 2005

Effects of unfavourable environmental conditions (stresses) induce stressor specific and unspecif... more Effects of unfavourable environmental conditions (stresses) induce stressor specific and unspecific shortand long-term responses in plants. Long-term responses depend on intensity and duration of the stress. Short-term effects comprise the accumulation of reactive oxygen species (ROS), membrane damages by the oxidation of fatty acids, and the release of amino alcohols. They can incite higher stress tolerance in plants.

Uranium - Past and Future Challenges, 2014

Uranium in the Aquatic Environment, 2002

The New Uranium Mining Boom, 2011

Biological trace element research, 2013

Several fungal species are notorious for the preferential acquisition of toxicants such as AsCdHg... more Several fungal species are notorious for the preferential acquisition of toxicants such as AsCdHgPbU in their wild-grown basidiomes, but it is not known how, or whether at all, mineral uptake is regulated. In this study, basidiomes of Kuehneromyces mutabilis, Pleurotus ostreatus, and Hypholoma fasciculare were grown on Fagus sylvatica logs embedded in sand, uranium-overburden soil, and garden soil (SIO) at a lab scale to raise the accessible mineral resources 30 to >1,000 times over those available in the timber alone. Non-embedded logs and a field culture established on SIO served as controls. Concentrations of 22 minerals were determined by inductively coupled plasma mass spectrometry from microwave-digested samples of timber, soils, whole and dissected mushrooms, and basidiospores. It was the goal to determine whether mineral uptake rates vary simply with their concentration in the substrate or undergo selections which indicate the ability of metal sensing and optimizing/delim...

Biodegradation, 1999

Seven commercial 3- to 7-ring (R) polycyclic aromatic hydrocarbons (PAH) as well as PAH derived f... more Seven commercial 3- to 7-ring (R) polycyclic aromatic hydrocarbons (PAH) as well as PAH derived from lignite tar were spiked into 3 soils (0.8 to 9.7% of organic carbon). The disappearance of the original PAH was determined for the freshly spiked soils, for soils incubated for up to 287 d with their indigenous microflora, and for autoclaved, unsterile and pasteurized soils inoculated with basidiomycetous and ascomycetous fungi. Three to 12 d after spiking, 22 to 38% of the PAH could no longer be recovered from the soils. At 287 d, 88.5 to 92.7%, 83.4 to 87.4%, and 22.0 to 42.1% of the 3-, 4-, and 5- to 7-R PAH, respectively, had disappeared from the unsterile, uninoculated soils. In 2 organic-rich sterile soils, the groups of wood- and straw-degrading, terricolous, and ectomycorrhizal fungi reduced the concentration of 5 PAH by 12.6, 37.9, and 9.4% in 287 d. Five- to 7-R PAH were degraded as efficiently as most of the 3- to 4-R PAH. In organic-rich unsterile soils inoculated with wo...

Uranium in the Environment, 2006

Page 1. Variation in heavy metal uptake by crop plants Hans Bergmann, Klaus-Dieter Voigt, Bernd M... more Page 1. Variation in heavy metal uptake by crop plants Hans Bergmann, Klaus-Dieter Voigt, Bernd Machelett, Gerhard Gramss Friedrich-Schiller-University, Institute of Nutrition, Dornburger Strasse 25, D-07743 Jena, Germany Abstract. ...

Uranium in the Environment, 2006

Page 1. Soil treatment with nitrogen facilitates continuous phytoextraction of heavy metals Gerha... more Page 1. Soil treatment with nitrogen facilitates continuous phytoextraction of heavy metals Gerhard Gramss1, Georg Büchel2, Hans Bergmann1 1Friedrich-Schiller-University, Institute of Nutrition, Dornburger Strasse 25, D-07743 ...

Biodegradation, 1999

Seven commercial 3- to 7-ring (R) polycyclic aromatic hydrocarbons (PAH) as well as PAH derived f... more Seven commercial 3- to 7-ring (R) polycyclic aromatic hydrocarbons (PAH) as well as PAH derived from lignite tar were spiked into 3 soils (0.8 to 9.7% of organic carbon). The disappearance of the original PAH was determined for the freshly spiked soils, for soils incubated for up to 287 d with their indigenous microflora, and for autoclaved, unsterile and pasteurized

New Phytologist, 1998

Aqueous extracts of homogenized shoot and root tissue of alfalfa (Medicago sativa L.), white must... more Aqueous extracts of homogenized shoot and root tissue of alfalfa (Medicago sativa L.), white mustard (Sinapis alba L.), and cress (Lepidium sativum L.), with the exudates of sterile roots of these crop plants, were examined spectrophotometrically for the activities of 20 oxidoreductase enzymes by standard procedures. In tissue extracts and root exudates, the reactions of laccase (EC 1;10;3;2), ascorbate oxidase (EC 1;10;3;3), monophenol monooxygenase (EC 1;14;18;1), and phenol 2-monooxygenase (EC 1;14;13;7) were readily detected. Of the aromatic-ring cleavage dioxygenases, those of the meta-cleavage pathway (EC 1;13;11;2 and 1;13;11;8) could also be detected. Guaiacol peroxidase (EC 1;11;1;7) was dominant in all samples. In sterile root exudates of alfalfa, this enzyme was represented by at least seven acidic isoforms. The formation of the ligninolytic Mn$ + \malonate and Mn$ + \citrate complexes from Mn# + occurred in all tissue extracts and in root exudates of alfalfa. In root extracts of soybean (Glycine max L.), the rate of Mn$ + generation correlated (P l 0n993) with the activities of endogenous plant guaiacol peroxidase and horseradish peroxidase (HRP) supplements and also with the total phenol content in tissue extracts (P l 0n984). Plant guaiacol peroxidase and purified HRP decolorized four aromatic dyes, an activity reported to be involved in ligninolysis. Although no enzymes capable of generating H # O # as a consequence of the oxidation of simple sugars, amino acids, organic acids, and aldehydes were found, traces of peroxide were detected in tissue extracts and in the root exudate of alfalfa. It is concluded that the oxidoreductases found in plant tissues also occur in root exudates of aseptic whole plants. The significance of interrelations between oxidoreductase enzymes and enzymically generated higher-valency metal ions is discussed in the context of the oxidative conversion of phenolic compounds in soil and plant tissue.

Microbial Ecology, 1999

An alkaline humic extract (HE) of a black calcareous forest mull was exposed to 36 fungal and 9 e... more An alkaline humic extract (HE) of a black calcareous forest mull was exposed to 36 fungal and 9 eubacterial isolates in liquid standing culture. At 21 d in fungi, and 4 d in bacteria, the groups of wood-degrading basidiomycetes, terricolous basidiomycetes, ectomycorrhizal fungi, soil-borne microfungi, and eubacteria had reduced the absorbance (A 340 ) of HE media by 57, 28, 19, 26 and 5%, respectively. Gel permeation chromatography revealed that the large humic acid molecules were more readily degraded than the smaller fulvic acid molecules and served as a sole source of carbon and energy. The more active HE degraders reduced the overall molecular weight of humic and fulvic acids by 0.25 to 0.47 kDa. They also reduced the chemical reactivity of HE to tetrazotized odianisidine, indicating the degradation of hydroxylated aromatic molecules (which are responsible for this reaction). Decreases in absorbance, molecular weight, and reactivity were caused by fungal manganese peroxidase, horseradish peroxidase, ␤-glucosidase, and abiotic oxidants such as H 2 O 2 and Mn(III) acetate. It is concluded that fungi, some of which are propagated in contaminated soils to control xenobiotics, metabolize HE compounds enzymatically. They use enzymes which are also involved in the degradation of soil xenobiotics. Because of reductions in the molecular weight of HE, which is a potential carrier of heavy metal ions and xenobiotics, solubility and motility of humic substances in soil and surface waters are increased.

Microbial Ecology, 2008

Non-symbiotic microorganisms engineered or expensively selected to degrade xenobiotic hydrocarbon... more Non-symbiotic microorganisms engineered or expensively selected to degrade xenobiotic hydrocarbons or modify heavy-metal uptake of plants in soil remediations die back after their introduction into the target soils. Mycelia of saprobic basidiomycetes were therefore inoculated into soil samples of 1 l in glass vessels to record mycelial growth and reproduction in the immediate rhizosphere of up to 11 herbaceous plant species, or to study their responses to the separate volatiles from whole plant swards or their root balls whose emanations had been collected in 1.5-l plastic bags fixed to the glass vessels. Excess CO 2 was controlled with NaOH solution. Volatiles from root balls of parsley and pea but not wheat, from unplanted soils, from the funguspermeated, unplanted substrate soil itself, and from the rooting soil of whole wheat sward increased mycelial densities in Clitocybe sp. more than in Agaricus macrocarpus and indicated thus a higher nutrient state of the mycelia. Organic volatiles proved therefore to be a significant carbon source for certain basidiomycetes in poor natural soils. The contemporary decline in the number of basidiocarp initials to 0 to 36% in both fungi relative to the unplanted and aerated controls was caused by volatiles from rooted and unplanted soil and pointed thus to their ecological role as antibiotics, fumigants, toxins, and hormonal compounds. Aqueous extracts from root balls of wheat stimulated mycelial density and fruiting in A. macrocarpus contemporarily because of their contents in soil-derived macronutrients. They suppressed once more fruiting in the more sensitive Clitocybe sp. by active agents in the aqueous phase. Within plant rhizospheres, densities of Clitocybe sp. mycelia were stimulated in the presence of alfalfa, carrot, red clover, ryegrass, and spinach, whereas those of A. macrocarpus were halved by 7 of 10 plant species including alfalfa, red clover, ryegrass, and spinach. Mycelia of A. macrocarpus may thereby have responded to differences in concentration and composition of volatile compounds. The contemporary repression of fruiting in both fungi and in nearly all treatments was not due to plant competition for macronutrients. Mycelia of basidiomycetes over-compensated for losses in macronutrients to the plant by decomposing soil matrix constituents. It is concluded that organic volatiles emitted by several plant organs and natural soils improved the nutritional state of A. macrocarpus and Clitocybe sp. but not of Agaricus bisporus mycelia and could therefore help establish certain ground fungi in the field. The contemporary and general suppression of fruiting by constituents of the gaseous (and liquid) phase in all fungi examined suggests interference with basic physiological processes and recommends an urgent re-examination of the degradative ability of basidiomycetes in the presence of volatiles.

Journal of Plant Nutrition and Soil Science, 2003

Journal of Plant Nutrition and Soil Science, 2004

Page 1. ã 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim 1436-8730/04/0408-417 J. Pl... more Page 1. ã 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim 1436-8730/04/0408-417 J. Plant Nutr. Soil Sci. 2004, 167, 417±427 DOI: 10.1002/jpln.200421353 Plant availability and leaching of (heavy) metals from ammonium ...

Journal of Basic Microbiology, 2005

Factors influencing water solubility and plant availability of mineral compounds in the tripartit... more Factors influencing water solubility and plant availability of mineral compounds in the tripartite fairy rings of Marasmius oreades (BOLT.: FR.) FR.

Journal of Basic Microbiology, 2011

Liquid and volatile emanations in interactions of soil basidiomycetes with herbs affect fungal ox... more Liquid and volatile emanations in interactions of soil basidiomycetes with herbs affect fungal oxidoreductases and stress-related plant peroxidases (PO). In this study, gnotobiotic co-cultures between 6 non-pathogenic saprobes and 2 ectomycorrhizal basidiomycetes with the non-host plant white mustard were established on glucose-salt medium with the respective controls. Determined were oxidoreductase activities for culture fluids and plant tissues at initial fungal idiophase and degradation rates of Remazol-BBR and 5 PAHs. In culture fluids of Agaricus arvensis, A. porphyrizon, Lepista nebularis, Stropharia rugoso-annulata, and Hypholoma fasciculare (group-5), the laccase-deficient plant enabled activity increases in fungal laccase (by 2300-fold), in extracellular (fungal and?) plant-derived peroxidases (by 21-fold), and in the dissipation of phenanthrene and anthracene. Oxidative activities in roots rose by 46000-fold during adsorption of fungal laccases. Increases in the stress-related shoot-PO (by 4.1-fold) were exclusively elicited by group-5 saprobes and correlated with plant-phenolic-mediated formations of Mn(III) and increases in Remazol BBR bleaching. Agaricus bisporus and the ectomycorrhizal Hebeloma crustuliniforme and Suillus granulatus did not respond to plant emanations with elevated laccase activities but solubilized apparently root-surface PO. They failed to elicit stress-related activity increases of PO in white mustard shoot and prevented Mn(III) formation in several tissues. It is concluded that white mustard emanations promoted the catabolic performance of the plantstress eliciting group-5 saprobes but not of A. bisporus and the ectomycorrhizal fungi with their low stress-inducing potential. The nature of the plant-released stimuli and the classes of fungus-released stress agents discussed must be determined in further studies.

Mycological Research, 1998

Microbial Ecology, May 28, 2008

Non-symbiotic microorganisms engineered or expensively selected to degrade xenobiotic hydrocarbon... more Non-symbiotic microorganisms engineered or expensively selected to degrade xenobiotic hydrocarbons or modify heavy-metal uptake of plants in soil remediations die back after their introduction into the target soils. Mycelia of saprobic basidiomycetes were therefore inoculated into soil samples of 1 l in glass vessels to record mycelial growth and reproduction in the immediate rhizosphere of up to 11 herbaceous plant species, or to study their responses to the separate volatiles from whole plant swards or their root balls whose emanations had been collected in 1.5-l plastic bags fixed to the glass vessels. Excess CO 2 was controlled with NaOH solution. Volatiles from root balls of parsley and pea but not wheat, from unplanted soils, from the funguspermeated, unplanted substrate soil itself, and from the rooting soil of whole wheat sward increased mycelial densities in Clitocybe sp. more than in Agaricus macrocarpus and indicated thus a higher nutrient state of the mycelia. Organic volatiles proved therefore to be a significant carbon source for certain basidiomycetes in poor natural soils. The contemporary decline in the number of basidiocarp initials to 0 to 36% in both fungi relative to the unplanted and aerated controls was caused by volatiles from rooted and unplanted soil and pointed thus to their ecological role as antibiotics, fumigants, toxins, and hormonal compounds. Aqueous extracts from root balls of wheat stimulated mycelial density and fruiting in A. macrocarpus contemporarily because of their contents in soil-derived macronutrients. They suppressed once more fruiting in the more sensitive Clitocybe sp. by active agents in the aqueous phase. Within plant rhizospheres, densities of Clitocybe sp. mycelia were stimulated in the presence of alfalfa, carrot, red clover, ryegrass, and spinach, whereas those of A. macrocarpus were halved by 7 of 10 plant species including alfalfa, red clover, ryegrass, and spinach. Mycelia of A. macrocarpus may thereby have responded to differences in concentration and composition of volatile compounds. The contemporary repression of fruiting in both fungi and in nearly all treatments was not due to plant competition for macronutrients. Mycelia of basidiomycetes over-compensated for losses in macronutrients to the plant by decomposing soil matrix constituents. It is concluded that organic volatiles emitted by several plant organs and natural soils improved the nutritional state of A. macrocarpus and Clitocybe sp. but not of Agaricus bisporus mycelia and could therefore help establish certain ground fungi in the field. The contemporary and general suppression of fruiting by constituents of the gaseous (and liquid) phase in all fungi examined suggests interference with basic physiological processes and recommends an urgent re-examination of the degradative ability of basidiomycetes in the presence of volatiles.

J Basic Microb, 2005

Factors influencing water solubility and plant availability of mineral compounds in the tripartit... more Factors influencing water solubility and plant availability of mineral compounds in the tripartite fairy rings of Marasmius oreades (BOLT.: FR.) FR.

Plant Growth Regulation, 2005

Effects of unfavourable environmental conditions (stresses) induce stressor specific and unspecif... more Effects of unfavourable environmental conditions (stresses) induce stressor specific and unspecific shortand long-term responses in plants. Long-term responses depend on intensity and duration of the stress. Short-term effects comprise the accumulation of reactive oxygen species (ROS), membrane damages by the oxidation of fatty acids, and the release of amino alcohols. They can incite higher stress tolerance in plants.

Uranium - Past and Future Challenges, 2014

Uranium in the Aquatic Environment, 2002

The New Uranium Mining Boom, 2011

Biological trace element research, 2013

Several fungal species are notorious for the preferential acquisition of toxicants such as AsCdHg... more Several fungal species are notorious for the preferential acquisition of toxicants such as AsCdHgPbU in their wild-grown basidiomes, but it is not known how, or whether at all, mineral uptake is regulated. In this study, basidiomes of Kuehneromyces mutabilis, Pleurotus ostreatus, and Hypholoma fasciculare were grown on Fagus sylvatica logs embedded in sand, uranium-overburden soil, and garden soil (SIO) at a lab scale to raise the accessible mineral resources 30 to >1,000 times over those available in the timber alone. Non-embedded logs and a field culture established on SIO served as controls. Concentrations of 22 minerals were determined by inductively coupled plasma mass spectrometry from microwave-digested samples of timber, soils, whole and dissected mushrooms, and basidiospores. It was the goal to determine whether mineral uptake rates vary simply with their concentration in the substrate or undergo selections which indicate the ability of metal sensing and optimizing/delim...

Biodegradation, 1999

Seven commercial 3- to 7-ring (R) polycyclic aromatic hydrocarbons (PAH) as well as PAH derived f... more Seven commercial 3- to 7-ring (R) polycyclic aromatic hydrocarbons (PAH) as well as PAH derived from lignite tar were spiked into 3 soils (0.8 to 9.7% of organic carbon). The disappearance of the original PAH was determined for the freshly spiked soils, for soils incubated for up to 287 d with their indigenous microflora, and for autoclaved, unsterile and pasteurized soils inoculated with basidiomycetous and ascomycetous fungi. Three to 12 d after spiking, 22 to 38% of the PAH could no longer be recovered from the soils. At 287 d, 88.5 to 92.7%, 83.4 to 87.4%, and 22.0 to 42.1% of the 3-, 4-, and 5- to 7-R PAH, respectively, had disappeared from the unsterile, uninoculated soils. In 2 organic-rich sterile soils, the groups of wood- and straw-degrading, terricolous, and ectomycorrhizal fungi reduced the concentration of 5 PAH by 12.6, 37.9, and 9.4% in 287 d. Five- to 7-R PAH were degraded as efficiently as most of the 3- to 4-R PAH. In organic-rich unsterile soils inoculated with wo...

Uranium in the Environment, 2006

Page 1. Variation in heavy metal uptake by crop plants Hans Bergmann, Klaus-Dieter Voigt, Bernd M... more Page 1. Variation in heavy metal uptake by crop plants Hans Bergmann, Klaus-Dieter Voigt, Bernd Machelett, Gerhard Gramss Friedrich-Schiller-University, Institute of Nutrition, Dornburger Strasse 25, D-07743 Jena, Germany Abstract. ...

Uranium in the Environment, 2006

Page 1. Soil treatment with nitrogen facilitates continuous phytoextraction of heavy metals Gerha... more Page 1. Soil treatment with nitrogen facilitates continuous phytoextraction of heavy metals Gerhard Gramss1, Georg Büchel2, Hans Bergmann1 1Friedrich-Schiller-University, Institute of Nutrition, Dornburger Strasse 25, D-07743 ...

Biodegradation, 1999

Seven commercial 3- to 7-ring (R) polycyclic aromatic hydrocarbons (PAH) as well as PAH derived f... more Seven commercial 3- to 7-ring (R) polycyclic aromatic hydrocarbons (PAH) as well as PAH derived from lignite tar were spiked into 3 soils (0.8 to 9.7% of organic carbon). The disappearance of the original PAH was determined for the freshly spiked soils, for soils incubated for up to 287 d with their indigenous microflora, and for autoclaved, unsterile and pasteurized

New Phytologist, 1998

Aqueous extracts of homogenized shoot and root tissue of alfalfa (Medicago sativa L.), white must... more Aqueous extracts of homogenized shoot and root tissue of alfalfa (Medicago sativa L.), white mustard (Sinapis alba L.), and cress (Lepidium sativum L.), with the exudates of sterile roots of these crop plants, were examined spectrophotometrically for the activities of 20 oxidoreductase enzymes by standard procedures. In tissue extracts and root exudates, the reactions of laccase (EC 1;10;3;2), ascorbate oxidase (EC 1;10;3;3), monophenol monooxygenase (EC 1;14;18;1), and phenol 2-monooxygenase (EC 1;14;13;7) were readily detected. Of the aromatic-ring cleavage dioxygenases, those of the meta-cleavage pathway (EC 1;13;11;2 and 1;13;11;8) could also be detected. Guaiacol peroxidase (EC 1;11;1;7) was dominant in all samples. In sterile root exudates of alfalfa, this enzyme was represented by at least seven acidic isoforms. The formation of the ligninolytic Mn$ + \malonate and Mn$ + \citrate complexes from Mn# + occurred in all tissue extracts and in root exudates of alfalfa. In root extracts of soybean (Glycine max L.), the rate of Mn$ + generation correlated (P l 0n993) with the activities of endogenous plant guaiacol peroxidase and horseradish peroxidase (HRP) supplements and also with the total phenol content in tissue extracts (P l 0n984). Plant guaiacol peroxidase and purified HRP decolorized four aromatic dyes, an activity reported to be involved in ligninolysis. Although no enzymes capable of generating H # O # as a consequence of the oxidation of simple sugars, amino acids, organic acids, and aldehydes were found, traces of peroxide were detected in tissue extracts and in the root exudate of alfalfa. It is concluded that the oxidoreductases found in plant tissues also occur in root exudates of aseptic whole plants. The significance of interrelations between oxidoreductase enzymes and enzymically generated higher-valency metal ions is discussed in the context of the oxidative conversion of phenolic compounds in soil and plant tissue.

Microbial Ecology, 1999

An alkaline humic extract (HE) of a black calcareous forest mull was exposed to 36 fungal and 9 e... more An alkaline humic extract (HE) of a black calcareous forest mull was exposed to 36 fungal and 9 eubacterial isolates in liquid standing culture. At 21 d in fungi, and 4 d in bacteria, the groups of wood-degrading basidiomycetes, terricolous basidiomycetes, ectomycorrhizal fungi, soil-borne microfungi, and eubacteria had reduced the absorbance (A 340 ) of HE media by 57, 28, 19, 26 and 5%, respectively. Gel permeation chromatography revealed that the large humic acid molecules were more readily degraded than the smaller fulvic acid molecules and served as a sole source of carbon and energy. The more active HE degraders reduced the overall molecular weight of humic and fulvic acids by 0.25 to 0.47 kDa. They also reduced the chemical reactivity of HE to tetrazotized odianisidine, indicating the degradation of hydroxylated aromatic molecules (which are responsible for this reaction). Decreases in absorbance, molecular weight, and reactivity were caused by fungal manganese peroxidase, horseradish peroxidase, ␤-glucosidase, and abiotic oxidants such as H 2 O 2 and Mn(III) acetate. It is concluded that fungi, some of which are propagated in contaminated soils to control xenobiotics, metabolize HE compounds enzymatically. They use enzymes which are also involved in the degradation of soil xenobiotics. Because of reductions in the molecular weight of HE, which is a potential carrier of heavy metal ions and xenobiotics, solubility and motility of humic substances in soil and surface waters are increased.

Microbial Ecology, 2008

Non-symbiotic microorganisms engineered or expensively selected to degrade xenobiotic hydrocarbon... more Non-symbiotic microorganisms engineered or expensively selected to degrade xenobiotic hydrocarbons or modify heavy-metal uptake of plants in soil remediations die back after their introduction into the target soils. Mycelia of saprobic basidiomycetes were therefore inoculated into soil samples of 1 l in glass vessels to record mycelial growth and reproduction in the immediate rhizosphere of up to 11 herbaceous plant species, or to study their responses to the separate volatiles from whole plant swards or their root balls whose emanations had been collected in 1.5-l plastic bags fixed to the glass vessels. Excess CO 2 was controlled with NaOH solution. Volatiles from root balls of parsley and pea but not wheat, from unplanted soils, from the funguspermeated, unplanted substrate soil itself, and from the rooting soil of whole wheat sward increased mycelial densities in Clitocybe sp. more than in Agaricus macrocarpus and indicated thus a higher nutrient state of the mycelia. Organic volatiles proved therefore to be a significant carbon source for certain basidiomycetes in poor natural soils. The contemporary decline in the number of basidiocarp initials to 0 to 36% in both fungi relative to the unplanted and aerated controls was caused by volatiles from rooted and unplanted soil and pointed thus to their ecological role as antibiotics, fumigants, toxins, and hormonal compounds. Aqueous extracts from root balls of wheat stimulated mycelial density and fruiting in A. macrocarpus contemporarily because of their contents in soil-derived macronutrients. They suppressed once more fruiting in the more sensitive Clitocybe sp. by active agents in the aqueous phase. Within plant rhizospheres, densities of Clitocybe sp. mycelia were stimulated in the presence of alfalfa, carrot, red clover, ryegrass, and spinach, whereas those of A. macrocarpus were halved by 7 of 10 plant species including alfalfa, red clover, ryegrass, and spinach. Mycelia of A. macrocarpus may thereby have responded to differences in concentration and composition of volatile compounds. The contemporary repression of fruiting in both fungi and in nearly all treatments was not due to plant competition for macronutrients. Mycelia of basidiomycetes over-compensated for losses in macronutrients to the plant by decomposing soil matrix constituents. It is concluded that organic volatiles emitted by several plant organs and natural soils improved the nutritional state of A. macrocarpus and Clitocybe sp. but not of Agaricus bisporus mycelia and could therefore help establish certain ground fungi in the field. The contemporary and general suppression of fruiting by constituents of the gaseous (and liquid) phase in all fungi examined suggests interference with basic physiological processes and recommends an urgent re-examination of the degradative ability of basidiomycetes in the presence of volatiles.

Journal of Plant Nutrition and Soil Science, 2003

Journal of Plant Nutrition and Soil Science, 2004

Page 1. ã 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim 1436-8730/04/0408-417 J. Pl... more Page 1. ã 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim 1436-8730/04/0408-417 J. Plant Nutr. Soil Sci. 2004, 167, 417±427 DOI: 10.1002/jpln.200421353 Plant availability and leaching of (heavy) metals from ammonium ...

Journal of Basic Microbiology, 2005

Factors influencing water solubility and plant availability of mineral compounds in the tripartit... more Factors influencing water solubility and plant availability of mineral compounds in the tripartite fairy rings of Marasmius oreades (BOLT.: FR.) FR.

Journal of Basic Microbiology, 2011

Liquid and volatile emanations in interactions of soil basidiomycetes with herbs affect fungal ox... more Liquid and volatile emanations in interactions of soil basidiomycetes with herbs affect fungal oxidoreductases and stress-related plant peroxidases (PO). In this study, gnotobiotic co-cultures between 6 non-pathogenic saprobes and 2 ectomycorrhizal basidiomycetes with the non-host plant white mustard were established on glucose-salt medium with the respective controls. Determined were oxidoreductase activities for culture fluids and plant tissues at initial fungal idiophase and degradation rates of Remazol-BBR and 5 PAHs. In culture fluids of Agaricus arvensis, A. porphyrizon, Lepista nebularis, Stropharia rugoso-annulata, and Hypholoma fasciculare (group-5), the laccase-deficient plant enabled activity increases in fungal laccase (by 2300-fold), in extracellular (fungal and?) plant-derived peroxidases (by 21-fold), and in the dissipation of phenanthrene and anthracene. Oxidative activities in roots rose by 46000-fold during adsorption of fungal laccases. Increases in the stress-related shoot-PO (by 4.1-fold) were exclusively elicited by group-5 saprobes and correlated with plant-phenolic-mediated formations of Mn(III) and increases in Remazol BBR bleaching. Agaricus bisporus and the ectomycorrhizal Hebeloma crustuliniforme and Suillus granulatus did not respond to plant emanations with elevated laccase activities but solubilized apparently root-surface PO. They failed to elicit stress-related activity increases of PO in white mustard shoot and prevented Mn(III) formation in several tissues. It is concluded that white mustard emanations promoted the catabolic performance of the plantstress eliciting group-5 saprobes but not of A. bisporus and the ectomycorrhizal fungi with their low stress-inducing potential. The nature of the plant-released stimuli and the classes of fungus-released stress agents discussed must be determined in further studies.