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PubMed2003

Colonisation of spruce roots by two interacting ectomycorrhizal fungi in wood ash amended substrates.

Interactions between two ectomycorrhizal fungal species, Piloderma croceum Erikss. and Hjortst. and Piloderma sp. 1 (found to colonise spruce roots and wood ash granules in the field), were investigated in wood ash amended substrates. The comparative ability of these fungi to colonise roots of non-mycorrhizal spruce (Picea abies (L.) Karst.) seedlings was studied in relation to factorial combinations of wood ash and N fertilisation. Non-mycorrhizal spruce seedlings (bait seedlings) were planted together with spruce seedlings colonised by P. croceum or Piloderma sp. 1. The growth substrate was a sand-peat mixture with wood ash or no ash and supplied with two levels of N, so that four substrate combinations were obtained. Piloderma sp. 1 mycelia colonised around 60% of the fine roots of bait seedlings in ash treatments regardless of N level and around 20-26% in treatments without ash. P. croceum only colonised 8% of the root tips in the presence of ash but 56% of the root tips in the low-N treatment without ash. However, in the high-N treatment without ash the colonisation level was reduced to around 30%. Total numbers of root tips per seedling did not vary significantly between the treatments. Possible reasons for the competitive advantage of Piloderma sp. 1 in wood ash fertilised substrate are discussed.

Basidiomycota↗

PubMed2000

[Did the Erve Valley in Mayenne (the Armoricain Massif, France) play the role of a refuge station during the last (Weichsélien) glaciation?].

Palynological analysis of the basal sedimentary sequence of a peat bog in the upper northeastern part of Mayenne (Massif Armoricain, France) revealed the existence of two temperate oscillations towards the end of the Weichselian glaciation, which were related chronologically by AMS C14 dating to the Kesselt and Tursac interstadials already reported at cave sites. Pollen diagrams recorded mesothermophilic arboreal taxa apparently disseminated from a refuge station possibly corresponding to the Erve valley.

Climate↗

PubMed2002

Perception of happy and sad facial expressions in chronic schizophrenia: evidence for two evaluative systems.

BACKGROUND: Persons suffering from schizophrenia have impaired perception of emotional expressions, but it is not clear whether this is part of a generalized deficit in cognitive function. AIM: To test for existence of emotion-specific deficits by studying the effects of valence on recognition of facial emotional expressions. METHODS: 24 male subjects suffering from chronic schizophrenia were examined with two tests of perception of emotion: the Penn Emotion Acuity Test (PEAT 40) and the Emotion Differentiation Task (EMODIFF). Clinical state was assessed with the Scale for the Assessment of Negative Symptoms (SANS) and Scale for the Assessment of Positive Symptoms (SAPS), visual memory with the Benton Visual Retention Test (BVRT) and motor function with the finger tapping test. RESULTS: Identification of happy facial expressions showed significant negative correlation with age, cumulated time in hospital and length of current hospitalization; positive correlations were found with visual retention and finger tapping scores. Identification of sad facial expressions showed significant correlation only with cumulated time in hospital while identification of neutral facial expressions showed no significant correlations. Discrimination between degrees of happy but not sad facial expression showed a positive correlation with negative symptoms. CONCLUSION: Perception of happy and sad emotion relates differently to significant illness parameters. This differentiability supports the existence of an emotion-specific deficit in perception of emotions in schizophrenia and of separate channels for processing positive and negative emotions.

Adult↗

PubMed2003

Microbial oxidation of methane from old landfills in biofilters.

Landfill gas emissions are among the largest sources of the greenhouse gas methane. For this reason, the possibilities of microbial methane degradation in biofilters were investigated. Different filter materials were tested in two experimental plants, a bench-scale plant (total filter volume 51 l) and a pilot plant (total filter volume 4 m3). Three months after the beginning of the experiment, very high degradation rates of up to 63 g CH4/(m3h) were observed in the bench-scale plant at mean methane concentrations of 2.5% v/v and with fine-grained compost as biofilter material. However, the degradation rates of the compost biofilter decreased in the fifth month of the experiment, probably due to the accumulation of exopolymeric substances formed by the microorganisms. A mixture of compost, peat, and wood fibers showed stable and satisfactory degradation rates around 20 g/(m3h) at mean concentrations of 3% v/v over a period of one year. In this material, the wood fibers served as a structural material and prevented clogging of the biofilter. Extrapolation of the experimental data indicates that biofilters for methane oxidation have to be at least 100 times the volume of biofilters for odor control to obtain the same cleaning efficiency per unit volume flow of feed gas.

Air Pollution↗

PubMed2001

Adapting substrate formulas used for shiitake for production of brown Agaricus bisporus.

A pasteurized, non-composted substrate (basal mixture) consisting of oak sawdust (28%), millet (29%), rye (8%), peat (8%), alfalfa meal (4%), soybean flour (4%), wheat bran (9%), and CaCO3 (10%) was adapted from shiitake culture to produce the common cultivated mushroom (brown; portabello), Agaricus bisporus. Percentage biological efficiency (ratio of fresh mushroom harvested/oven-dry substrate weight, %BE) ranged from a low of 30.1% (when wheat straw was substituted for sawdust) to 77.1% for the basal mixture. Special, high gas-exchange bags were required to optimize mycelial growth during spawn run. Our formula may allow specialty mushroom growers to produce portabello mushrooms on a modified, pasteurized (110 degrees C for 20 min) substrate commonly used for shiitake production without the added expense of compost preparation.

Agaricales↗

PubMed2002

Super blue box recycling (SUBBOR) enhanced two-stage anaerobic digestion process for recycling municipal solid waste: laboratory pilot studies.

The super blue box recycling (SUBBOR) process is an enhanced, multi-stage anaerobic digestion process for mixed municipal solid waste (MSW) and other biomass feedstock materials. The technology centers on enhanced high solids, thermophilic digestion after steam-pressure disruption of the ligno-cellulosic fiber components that are recalcitrant to conventional anaerobic digestion. Mixed MSW, rich in organic components but also containing inorganic materials, such as glass, aluminum and steel, as well as non-digestible plastic materials, has been laboratory pilot tested with a fully integrated process train designed to treat and recycle all of the MSW components. Methane yields from the MSW were 0.36 m3 CH4/kg volatile solids (VS) representing a 40% increase over the yield obtained from conventional single stage digestion. The secondary digestion step after steam pressure disruption also provided a 40% improvement in total solids and VS reduction. The residual organic fraction following two-stage digestion was fine in texture and was recovered as a clean peat fraction with reduced contents of heavy metal and other fugitive non-digested contaminants. Mass and energy balance determinations indicated a high degree of MSW diversion from landfill disposal (>80%) was achievable by the SUBBOR process as well as substantial net electrical and thermal energy production. Continuous long-term trials of the SUBBOR process at 25,000 tonnes/year are underway.

Anaerobiosis↗

PubMed2003

Effect of covering pig slurry stores on the ammonia emission processes.

The aim of this study was to evaluate the effects of different covers (oil, plastic film, perforated polystyrene float, peat and zeolites) on slurry settling characteristics and ammonia emission during storage and following surface application in the field. Laboratory trials were carried out for 15 days using a pilot scale device. Samples of 5 kg slurry were used. At the end of the storage period, distributions of dry matter, pH, total ammoniacal nitrogen and total Kjeldahl nitrogen in slurry were characterized. In the field, ammonia volatilisation was measured for three days using a wind tunnel system. Oil and plastic film retained all ammoniacal nitrogen forms in the slurry, whereas the others reduced ammonia volatilisation by reducing the emitting surface or by adsorbing/absorbing ammonia. Over the whole process studied (storage plus application) ammonia emissions were reduced by 40% by oil up to 65-71% by zeolites with different particle sizes.

Air Pollution↗

PubMed2003

Use of silica-immobilized humin for heavy metal removal from aqueous solution under flow conditions.

Humin extracted from Sphagnum peat moss was immobilized in a silica matrix and column experiments were performed in order to evaluate the removal and recovery of metal ions from aqueous solution under flow conditions. These experiments also allowed testing the recycling capacity of the column. Single-element solutions of Cu(II) and Pb(II), and a multi-metal solution containing Cd(II), Cu(II), Pb(II), Ni(II), and Cr(III) were passed through the columns at a flow rate of 2 ml/min. A 0.5 M sodium citrate solution was used as the stripping agent in the metal-ion recovery process. Humin immobilized in the silica matrix exhibited a similar, and in some cases, even a higher capacity than other biosorbents for the removal of metal ions from aqueous solutions under flow conditions. The sodium citrate was effective in removing Cu(II), Pb(II), Cd(II), and Ni(II) from the metal saturated column. The selectivity of the immobilized biomass was as follows: Cr(III)>Pb(II)>Cu(II)>Cd(II)>Ni(II). This investigation provides a new, environmentally friendly and cost-effective possibility to clean up heavy-metal contaminated wastewaters by using the new silica-immobilized humin material.

Adsorption↗

PubMed2001

Impacts of solar ultraviolet-B radiation on terrestrial ecosystems of Tierra del Fuego (southern Argentina). An overview of recent progress.

The southern part of Tierra del Fuego, in the southernmost tip of South America, is covered by dense Nothofagus spp. forests and Sphagnum-dominated peat bogs, which are subjected to the influence of ozone depletion and to increased levels of solar ultraviolet-B radiation (UV-B). Over the last 5 years we have studied some of the biological impacts of solar UV-B on natural ecosystems of this region. We have addressed two general problems: (i) do the fluctuations in UV-B levels under the influence of the Antarctic ozone 'hole' have any measurable biological impact, and (ii) what are the long-term effects of solar (ambient) UV-B on the Tierra del Fuego ecosystems? In this paper, we provide an overview of the progress made during the first 4 years of the project. We highlight and discuss the following results: (1) ambient UV-B has subtle but significant inhibitory effects on the growth of herbaceous and graminoid species of this region (growth reduction < or = 12%), whereas no consistent inhibitory effects could be detected in woody perennials; (2) in the species investigated in greatest detail, Gunnera magellanica, the inhibitory effect of solar UV-B is accompanied by increased levels of DNA damage in leaf tissue, and the DNA damage density in the early spring is clearly correlated with the dose of weighted UV-B measured at ground level; (3) the herbaceous species investigated thus far show little or no acclimation responses to ambient UV-B such as increased sunscreen levels and DNA repair capacity; and (4) ambient UV-B has significant effects on heterotrophic organisms, included marked inhibitory effects on insect herbivory. The results from the experiments summarized in this review clearly indicate that UV-B influences several potentially important processes and ecological interactions in the terrestrial ecosystems of Tierra del Fuego.

Animals↗

PubMed2001

Human cell mutagenicity of chlorinated and unchlorinated water and the disinfection byproduct 3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone (MX).

Extracts of three water samples--humic acid-enriched water-both peatland water and drinking water, both with and without chlorination were tested for mutagenicity at the tk locus in MCL-5 cells, a line of human B-lymphoblastoid cells that express cytochrome P450 enzymes and microsomal epoxide hydrolase. Our results show that chlorination caused a 5.5-fold increase (P<0.0001) in the mutagenicity of the humic acid-enriched water. The unchlorinated peatland water was mutagenic at the two highest doses (240 and 480 microg equivalent total organic carbon (TOC)/ml), possibly due to polycyclic aromatic hydrocarbons (PAH) that were measured in the peat. In contrast, the chlorinated peatland water was non-mutagenic at low doses, while at the highest dose (240 microg equivalent TOC/ml) the sample was so toxic that an insufficient number of cells survived treatment to allow plating. The chlorinated and unchlorinated drinking water were both non-mutagenic. 3-Chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone (MX), a potent bacterial mutagen and chlorine-disinfection byproduct, was also tested in MCL-5 cells as well as in two other human B-lymphoblastoid cell-lines, AHH-1 TK+/- and h1A1v2 cells, which differ from each other and from MCL-5 cells in the amounts of cytochrome P450 enzymes they can express. MX was mutagenic to all three cell-lines, but there was no apparent correlation between cytochrome P450 enzyme expression and the mutagenicity of MX. Overall, our results show that samples of chlorinated humic acid-enriched water and MX, a model chlorine-disinfection byproduct, are moderately mutagenic to human cells.

B-Lymphocytes↗

PubMed2003

[Role of man in the history of vegetation of the Ellero valley (maritime Alps, Italy)].

The pollen analysis of a sediment core from a peat bog (Rifugio Mondovi) at the mountain belt (1760 m) in the Ellero Valley (Italian Maritime Alps) shows the postglacial vegetation history. The sequence starts at 12,000 BP during a peak of pine pollen; this first phase shows a low representation of birch and the presence of Tilia. Younger Dryas is characterised by increasing percentages of Artemisia, showing the presence of deciduous Quercus, fir and beech. Elm appears at the beginning of the Holocene during the second pine peak (9800 BP). A 3000-year hiatus is present. Sedimentation resumes at 6000 BP in a Rhododendron fir-wood. The present timberline at 1500 m, at the limit of the beech wood, is a result of the decline of the fir-wood at 2600 BP, which allowed an expansion of beech. During this period, there was a continual increase in Gramineae and deciduous oak and the first occurrences of evergreen oak are observed. The development of larch occurs at 1800 BP, together with walnut, chestnut, cereals and vine.

Anthropology↗

PubMed2003

Heterobasidiomycetes form symbiotic associations with hepatics: Jungermanniales have sebacinoid mycobionts while Aneura pinguis (Metzgeriales) is associated with a Tulasnella species.

In order to evaluate substrate dependence of the symbiotic fungal associations in leafy liverworts (Jungermanniopsida), 28 species out of 12 families were investigated by transmission electron microscopy and molecular methods. Samples were obtained from the diverse substrates: from naked soil, from the forest floor on needle litter, from between peat moss, from rotten bark of standing trees, and from stumps and rotten wood. Associations with ascomycetes were found in most of the specimens independent from the substrate. Seven species sampled from soil were found to contain basidiomycete hyphae. Ultrastructure consistently showed dolipores with imperforate parenthesomes. Molecular phylogenetic studies revealed that three specimens belonging to the Jungermanniales were associated with members of Sebacinaceae, while Aneura pinguis (Metzgeriales) was associated with a Tulasnella species. These taxa are so far the only basidiomycetes known to be symbiotically associated with leafy liverworts. The probability that the associations with Sebacinaceae are evolutionary old, but the Tulasnella associations more derived is discussed. The sebacinoid mycobionts form a similar interaction type with the jungermannialian leafy liverworts as do the associated ascomycetes. The term 'jungermannioid mycorrhiza' is proposed for this distinctive symbiotic interaction type.

Basidiomycota↗

PubMed2002

Fast quantification of humic substances and organic matter by direct analysis of sediments using DRIFT spectroscopy.

A simple method based on diffuse reflectance coupled with infrared Fourier transform spectroscopy (DRIFTS) has been developed for the quantification and the characterization of sedimentary (or soil, peat, etc.) humic substances. Under optimized conditions, the quantification of humic substances or total organic matter is possible with DRIFTS at a frequency of 2930 cm(-1) using whole dry sediment samples. A study of the operational parameters that affect the DRIFTS signal shows the importance of normalizing analysis conditions, especially the diffuse reflectance accessory alignment, the particle size and compaction, and the homogeneity of the powdered samples, to obtain reproducible quantitative analyses. The quantification of total humic substances by DRIFTS correlates well with the concentrations determined using classical extraction methods. DRIFTS analysis requires only a few minutes instead of tedious extractions of humic substances. Moreover, the distribution of total organic matter and of fulvic acids, humic acids, and humin can also be obtained. Analysis of natural samples indicates that a calibration using humic material representative of the studied area provides the most accurate quantification. The fast screening of organic matter fractions by DRIFTS on intact natural samples provides useful quantitative and qualitative information that can be used in environmental or monitoring studies.

Algorithms↗

PubMed2003

Initial characterization of humic acids using liquid chromatography at the critical condition followed by size-exclusion chromatography and electrospray ionization mass spectrometry.

Structural information on humic acids is difficult to obtain because of the heterogeneity of the acids. Herein liquid chromatography at the critical condition, LCCC, is used to provide a sorting mechanism for the diverse types of molecules contained in humic acids. The critical condition of polymers that are believed to model some subunit of the humic acid is determined. Humic acids from three different terrestrial sources (soil, compost, and peat) are then separated under these chromatographic conditions. The portion of the humic acid that has structure similar to that of the model polymer elutes at the retention volume of the critical condition of the model. Next, fractions are collected and further characterized. This detailed characterization includes high-efficiency size-exclusion chromatography and electrospray mass spectrometry. The size-exclusion chromatograms of the fractions were found to be markedly different from that of the original humic acid sample. This is strong evidence that the LCCC separation mechanism is different from size fractionation. The mass spectra of the humic acid fractions were also markedly different from those of the bulk humic acids previously reported. The mass spectra of specific fractions collected had repeating clusters of m/z values, which is more evidence that the critical condition separation is a powerful sort function.

Journal Article↗

PubMed2005

Development of a proxy for past surface UV-B irradiation: a thermally assisted hydrolysis and methylation py-GC/MS method for the analysis of pollen and spores.

A method was developed for the analysis of the UV-absorbing sporopollenin monomers p-coumaric acid and ferulic acid in very low numbers of pollen. This enables the analysis of pollen or spores from cultured plants, from herbarium collections, and from sediment, soil, and peat cores. The method involves thermally assisted hydrolysis and methylation using tetramethylammonium hydroxide combined with gas chromatography and mass spectrometry. Pyrolysis, gas chromatographic, and mass spectrometric conditions were optimized for the analysis of minimal amounts of pollen. The method has a detection limit of approximately 60 fresh pollen of Alnus glutinosa and a relative standard deviation of approximately 10% between 100 and 600 pollen.

Alnus↗

PubMed2001

Americium binding to humic acid.

The binding of americium (Am) by peat humic acid (PHA) has been investigated at Am concentrations between 10(-1) and 10(-7) M at pH approximately 2.6 in the presence and absence of Cu as a competing ion. Cu-PHA binding was also investigated in order to derive independent binding constants for use in modeling the competitive binding studies. Humic ion-binding model VI was used to compare the acquired data with previously published binding data and to investigate the importance of high-affinity binding sites in metal-PHA binding. Am was not observed to bind to high-affinity, low-concentration binding sites. The model VI parameter deltaLK2 takes into accountthe small number of strong sites in PHA and was found to be important for Cu-PHA binding but not for Am-PHA binding, regardless of whether Cu was present. Analysis of the PHA sample revealed that it contained a considerable quantity of Fe not removed by the extraction procedure, much of which is believed to be present as Fe(III). Model VI was then used to investigate the possible importance of the presence of Fe(III) in the Am-PHA binding experiments. When Fe(III) was assumed to be present, improved descriptions of the data by model VI were obtained by assuming that all of the metals [Am, Cu, and Fe(III)] undergo strong binding. This highlights the importance of Fe(III) competition in metal-PHA binding studies and possible shortcomings in the extraction procedure used to extract PHA.

Americium↗

PubMed2001

Noncovalent interactions between monoaromatic compounds and dissolved humic acids: a deuterium NMR T1 relaxation study.

Deuterium nuclear magnetic resonance spectroscopy (2H NMR) spin-lattice relaxation (T1) experiments were used to examine solution-phase, noncovalent interactions between deuterated monoaromatic compounds (phenol-d5, pyridine-d5, benzene-d6) and Suwannee River, soil, and peat humic acids. Noncovalent interactions, in aqueous solution, were examined as a function of solution pH, monoaromatic hydrocarbon functional groups, and humic acid identity. Benzene interacted with dissolved humic acids at all pH values; however, these interactions increased with decreasing pH and generally were proportional with the humic acid percent aromaticity. Pyridine behaved similarly as benzene; however, two modes of interaction between pyridine and humic acids were detected as a function of pH and humic acid type: bonding with the lone pair of electrons of pyridine's nitrogen and pi-pi interactions between the aromatic ring of pyridine and aromatic components of humic acid. The latter interaction was favored by increasing humic acid percent aromaticity and decreasing solution pH. On the other hand, because of its strong capacity for hydrogen bonding, phenol interacted preferentially with water, except at pH values 5 or lower and with humic acids with 45% or greater aromaticity. Under these conditions, strong interactions between phenol and humic acids were observed. These results demonstrate that solution-phase, noncovalent interactions between monoaromatic compounds and humic acids are a function of solution pH, percent aromaticity, and the monoaromatic functional group.

Benzene↗

PubMed2001

New structural information on a humic acid from two-dimensional 1H-13C correlation solid-state nuclear magnetic resonance.

New information on the chemical structure of a peat humic acid has been obtained using a series of two-dimensional 1H-13C heteronuclear correlation solid-state NMR (HETCOR) experiments with different contact times and with spectral editing by dipolar dephasing and 13C transverse relaxation filtering. Carbon-bonded methyl groups (C-CH3) are found to be near both aliphatic and O-alkyl but not aromatic groups. The spectra prove that most OCH3 groups are connected directly with the aromatic rings, as is typical in lignin. As a result, about one-third of the aromatic C-O groups is not phenolic C-OH but C-OCH3. Both protonated and unprotonated anomeric O-C-O carbons are identified in the one- and two-dimensional spectra. COO groups are found predominantly in OCHn-COO environments, but some are also bonded to aromatic rings and aliphatic groups. All models of humic acids in the literature lack at least some of the features observed here. Compositional heterogeneity was studied by introducing 1H spin diffusion into the HETCOR experiment. Comparison with data for a synthetic polymer, polycarbonate, indicates that the separation between O-alkyl and aromatic groups in the humic acid is less than 1.5 nm. However, transverse 13C relaxation filtering under 1H decoupling reveals heterogeneity on a nanometer scale, with the slow-relaxing component being rich in lignin-like aromatic-C-O-CH3 moieties and poor in COO groups.

Carbon Isotopes↗