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At least 271 records · Page 15Linked to original sources
PubMed2005

Link between spatial structure of microbial communities and degradation of a complex mixture of volatile organic compounds in peat biofilters.

AIMS: To investigate the relationships between the operation of the volatile organic compound (VOC) removal biofilter and the structure of microbial communities, and to study the impact on degradation activities and the structuring of microbial communities of biofilter malfunctions related to the qualitative composition of the polluted air. METHODS AND RESULTS: A microbiological study and a measurement of biodegradation activities were simultaneously carried out on two identical peat-packed columns, seeded with two different inocula, treating polluted air containing 11 VOCs. For both reactors, the spatial structure of the microbial communities was investigated by means of single-strand conformation polymorphism (SSCP) analysis. For both reactors, stratification of degradation activities in function of depth was observed. Oxygenated compounds were removed at the top of the column and aromatics at the bottom. Comparison of SSCP patterns clearly showed a shift in community structure in function of depth inside both biofilters. This distribution of biodegradation activities correlates with the spatialization of microbial density and diversity. Although the operating conditions of both reactors were identical and the biodegradation activities similar, the composition of microflora differed for biofilters A and B. Subdivision of biofilter B into two independent parts supplied with polluted air containing the complex VOC mixture showed that the microflora having colonized the bottom of biofilter B retained their potential for degrading oxygenated compounds. CONCLUSIONS: This work highlights the spatialization of biodegradation functions in a biofilter treating a complex mixture of VOCs. This distribution of biodegradation activities correlates with the spatialization of microbial density and diversity. SIGNIFICANCE AND IMPACT OF THE STUDY: This vertical structure of microbial communities must be taken into consideration when dealing with the malfunctioning of bioreactors. These results are also useful information about changes in microbial communities following natural or anthropogenic alterations in different ecosystems (soils and sediments) where structuring of microbial communities according to depth has been observed.

Air Microbiology↗
PubMed2001

Pediatric emergency assessment tool (PEAT): a risk-adjustment measure for pediatric emergency patients.

OBJECTIVE: To develop a multivariable model predicting the level of care required by pediatric patients for use as a risk-adjustment tool in the evaluation of emergency medical services for children. METHODS: A random 10% sample of records of all visits over a 12-month period to a suburban, university-affiliated pediatric emergency department (PED) was selected and abstracted. The outcome variable, level of care received, was categorized in three levels: routine care only (R); diagnostic or therapeutic procedures performed in the ED but patient not admitted (EDT); and admission to hospital (ADM). Predictor variables included information routinely elicited and recorded at the time of triage. Using multinomial logistic regression, a predictive model was derived from a subset of 70% of the selected visits, and was validated in the remaining 30%. RESULTS: The total sample included 2,287 visits. The overall rate of each outcome was R-37%, EDT-53%, and ADM-10%. The final regression model included the following predictors significantly associated with the outcome: age, past medical history, temperature, abnormal respiratory rate or pulse oximetry in triage, chief complaint, and triage level (model likelihood ratio chi-square, 14 df = 332, p < 0.00001, R(2) = 0.14). The number of outcomes was well predicted by the model in both subsamples. Analysis of variance showed a significant association between Pediatric Emergency Assessment Tool (PEAT) score (weighted sum of the predicted probabilities of EDT and ADM) and both ED charges and time spent in the ED (p < 0.001). CONCLUSIONS: A model based on easily and routinely measured variables can accurately predict the level of care rendered in the PED. The predicted probabilities from such a model correlate well with other outcomes of care and may be useful in adjusting for differences in risk when evaluating quality of care.

Child, Preschool↗
PubMed1998

History of atmospheric lead deposition since 12,370 (14)C yr BP from a peat bog, jura mountains, switzerland

A continuous record of atmospheric lead since 12,370 carbon-14 years before the present (14C yr BP) is preserved in a Swiss peat bog. Enhanced fluxes caused by climate changes reached their maxima 10, 590 (14)C yr BP (Younger Dryas) and 8230 (14)C yr BP. Soil erosion caused by forest clearing and agricultural tillage increased lead deposition after 5320 (14)C yr BP. Increasing lead/scandium and decreasing lead-206/lead-207 beginning 3000 (14)C yr BP indicate the beginning of lead pollution from mining and smelting, and anthropogenic sources have dominated lead emissions ever since. The greatest lead flux (15.7 milligrams per square meter per year in A.D. 1979) was 1570 times the natural, background value (0.01 milligram per square meter per year from 8030 to 5320 (14)C yr BP).

Journal Article↗
PubMed1999

Mercury in a spanish peat bog: archive of climate change and atmospheric metal deposition

A peat core from a bog in northwest Spain provides a record of the net accumulation of atmospheric mercury since 4000 radiocarbon years before the present. It was found that cold climates promoted an enhanced accumulation and the preservation of mercury with low thermal stability, and warm climates were characterized by a lower accumulation and the predominance of mercury with moderate to high thermal stability. This record can be separated into natural and anthropogenic components. The substantial anthropogenic mercury component began approximately 2500 radiocarbon years before the present, which is near the time of the onset of mercury mining in Spain. Anthropogenic mercury has dominated the deposition record since the Islamic period (8th to 11th centuries A.D.). The results shown here have implications for the global mercury cycle and also imply that the thermal lability of the accumulated mercury can be used not only to quantify the effects of human activity, but also as a new tool for quantitative paleotemperature reconstruction.

Journal Article↗
PubMed2005

Effect of temperature on anaerobic ethanol oxidation and methanogenesis in acidic peat from a northern wetland.

The effects of temperature on rates and pathways of CH4 production and on the abundance and structure of the archaeal community were investigated in acidic peat from a mire in northern Scandinavia (68 degrees N). We monitored the production of CH4 and CO2 over time and measured the turnover of Fe(II), ethanol, and organic acids. All experiments were performed with and without specific inhibitors (2-bromoethanesulfonate [BES] for methanogenesis and CH3F for acetoclastic methanogenesis). The optimum temperature for methanogenesis was 25 degrees C (2.3 micromol CH4.g [dry weight](-1) . day(-1)), but the activity was relatively high even at 4 degrees C (0.25 micromol CH4. g [dry weight](-1) . day(-1)). The theoretical lower limit for methanogenesis was calculated to be at -5 degrees C. The optimum temperature for growth as revealed by real-time PCR was 25 degrees C for both archaea and bacteria. The population structure of archaea was studied by terminal restriction fragment length polymorphism analysis and remained constant over a wide temperature range. Hydrogenotrophic methanogenesis accounted for about 80% of the total methanogenesis. Most 16S rRNA gene sequences that were affiliated with methanogens and all McrA sequences clustered with the exclusively hydrogenotrophic order Methanobacteriales, correlating with the prevalence of hydrogenotrophic methanogenesis. Fe reduction occurred parallel to methanogenesis and was inhibited by BES, suggesting that methanogens were involved in Fe reduction. Based upon the observed balance of substrates and thermodynamic calculations, we concluded that the ethanol pool was oxidized to acetate by the following two processes: syntrophic oxidation with methanogenesis (i) as an H2 sink and (ii) as a reductant for Fe(III). Acetate accumulated, but a considerable fraction was converted to butyrate, making volatile fatty acids important end products of anaerobic metabolism.

Anaerobiosis↗
PubMed1996

Levels and identities of nonrhizobial microorganisms found in commercial legume inoculant made with nonsterile peat carrier.

Sixty samples of commercial North American legume inoculants manufactured for sale in 1994 using nonsterile peat as carrier were tested for Rhizobium (or Bradyrhizobium) content and non-Rhizobium biological contaminant load. Products of three major producers of such inoculants for sale in Canada were examined. Viable Rhizobium content varied from 5.6 x 10(5) to 8.1 x 10(9) cells/g, while the contaminant load varied from 1.8 x 10(8) to 5.5 x 10(10) cfu/g. Most of the inoculants contained more nonrhizobial organisms than they did rhizobia. Identifications were made of the most numerous nonrhizobial bacteria occurring in 100 samples of inoculants collected in 1993 and 1994. The most commonly identified contaminant was Xanthomonas maltophilia. Pseudomonas aeruginosa, Klebsiella pneumoniae, and Enterobacter cloacae were also found at high levels in some products. Contaminant organisms capable of inhibiting rhizobial growth in plate culture were found in the products of all three manufacturers.

Agriculture↗
PubMed2006

Insect biodiversity of boreal peat bogs.

Boreal peat bogs contain distinctive insects in addition to widely distributed generalists, including species restricted to bogs (tyrphobionts) and species characteristic of bogs but not confined to them (tyrphophiles). Bogs raised above the water table form characteristic habitat islands in southern boreal and temperate forest zones. Many bogs have persisted for hundreds and even thousands of years, preserving relict ecosystems related to subarctic biomes. The historical development and nature of individual bogs are reflected by differences among their insects, which are of great biogeographical and ecological interest. The environmental sensitivity of bogs also makes insects valuable as bioindicators. Moreover, few readily accessible bogs remain in a natural state. Given the scientific interest of bog insects and the fact that each relict bog habitat island is unique, further studies of the diversity of bog faunas are merited, and the conservation of these habitats should be strongly supported by entomologists.

Animals↗
PubMed2006

Trihalomethane reactivity of water- and sodium hydroxide-extractable organic carbon fractions from peat soils.

Certain organic carbon moieties in drinking source waters of the Sacramento-San Joaquin Delta can react with chlorine during disinfection to form potentially carcinogenic and mutagenic trihalomethanes. The properties of reactive organic carbon in Delta waters, particularly those of soil origin, have been poorly understood. This study attempts to characterize trihalomethane reactivity of soil organic carbon from three representative Delta peat soils. Soil organic carbon was extracted from all three soils with either deionized H2O or 0.1 M NaOH and sequentially separated into humic acids, fulvic acids, and nonhumic substances for quantitation of trihalomethane formation potential. Water-extractable organic carbon represented only 0.4 to 0.7% of total soil organic carbon, whereas NaOH extracted 38 to 51% of total soil organic carbon. The sizes and specific trihalomethane formation potential (STHMFP) of individual organic carbon fractions differed with extractants. Fulvic acids were the largest fraction in H2O-extractable organic carbon, whereas humic acids were the largest fraction in NaOH-extractable organic carbon. Among the fractions derived from H2O-extractable carbon, fulvic acids had the greatest specific ultraviolet absorbance and STHMFP and had the majority of reactive organic carbon. Among the fractions from NaOH-extractable organic carbon, humic acids and fulvic acids had similar STHMFP and, thus, were equally reactive. Humic acids were associated with the majority of trihalomethane reactivity of NaOH-extractable organic carbon. The nonhumic substances were less reactive than either humic acids or fulvic acids regardless of extractants. Specific ultraviolet absorbance was not a good predictor of trihalomethane reactivity of organic carbon fractions separated from the soils.

Carbon↗
PubMed2005

Micromonospora siamensis sp. nov., isolated from Thai peat swamp forest.

Morphological and chemotaxonomic characterization of actinomycete strain TT2-4T isolated from peat swamp forest soil in Pattaloong Province, Thailand, clearly demonstrated that this strain belongs to the genus Micromonospora. 16S rDNA sequence analysis for the strain supported the assignment of the strain to the genus Micromonospora and the similarity value of sequences between this strain and the closely related species, Micromonospora mirobrigensis was 99.1%, and M. carbonacea and M. matsumotoense were 98.8%. The DNA-DNA hybridization result and some physiological and biochemical properties indicated that strain TT2-4T was distinguished from the phylogenetically closest relatives. Based on these genotypic and phenotypic data, strain TT2-4T merits a new species in the genus Micromonospora and the name Micromonospora siamensis sp. nov. is proposed for the strain. The type strain is strain TT2-4T (=JCM 12769T =PCU 266T =TISTR 1554T).

Base Composition↗
PubMedDate not supplied

Directors' and officers' liability: a crisis in the making. A national survey conducted by Opinion Research Corporation and Research Strategies Corporation for Peat Marwick.

The survey upon which this column is based was mentioned in the last issue of VAL in the special report on H.R. 911, an important bill for the voluntary sector introduced by Representative John Porter (R-Ill.) in February. H.R. 911 encourages states to exempt all volunteers from civil liability except for acts of willful and wanton misconduct. The survey results are reprinted here with permission from the report, Directors' and Officers' Liability: A Crisis in the Making, which was based on a study of national not-for-profit voluntary organizations, undertaken by Peat Marwick in cooperation with INDEPENDENT SECTOR.

Administrative Personnel↗
PubMedDate not supplied

[Effect of oil on the size of number, biomass, and viability of fungi in highmoor peats].

Some microbiological parameters, such as the fungal mycelium length, the number of fungal spores, the distribution profiles of micromycetes, the viability of fungal propagules, the length distribution of micromycete hyphae, and the proportion between fungal spores and yeastlike cells, can be used to determine the degree of soil contamination with oil and the concentration that is inhibitory to the micromycete complexes of highmoor peats.

Biomass↗
PubMedDate not supplied

[Oribatid mites (Acariformes, Oribatei) as an index of postpyrogenous changes in podzol and peat soils of boreal forests].

Population changes of oribatid mites were studied in a bilberry-moss spruce stand and shrub-peat moss pine stand caused by ground fire. The fire resulted in a drop of population density and changes in the species composition of mites in both forest types. In the case of the spruce stand, the restoration of species composition proceeded parallel to the formation of a bilberry-moss cover and litter and became distinct four years after the fire. In the case of pine stand, the fire enveloped only the peripheral region. After the sphagnum cover burned out, the moor dehydration began and the mineralized organogenic substrate emerged. Here, the oribatid complex was significantly rearranged and the previously dominating moisture-loving species were replaced by the mesophilous-xerophilous species typical predominantly for mineralized soils. This explains why the oribatid species composition in the burned pine stand is more similar to that in the control spruce stand than to that in the control pine stand.

Animals↗
PubMed1992

[The effect of peat preparation on the release of histamine from basophils of atopic bronchial asthma].

Antigen-induced basophil histamine releasing (BHR) is an in vitro model of the immediate-type allergic reaction. We studied the influence of immunologically active peat preparation (PTT). On BHR induced with specific antigen or Con A. The highest concentration of PTT enhanced, but lower concentrations decreased antigen-induced BHR. Surprisingly, similar effect was observed with placebo, suggestions that immunologically inactive components of both preparations may be responsible for the modulatory activity.

Adult↗
PubMedDate not supplied

[Competing ability of Rhizobium trifolii strains and efficiency of clover nitraginization on spent peat mosses].

The competing ability of active strains of clover nodule bacteria was assayed in vegetation and field experiments. The competing ability of the industrial strains 311a and 347a was found to be sufficiently high. These strains increased the yield of clover on exhausted turf peats of the Kirovsk Region by 26--29%. The stimulating effect was observed also with new strains 313b and 329b. The optimal dose for inoculation of clover seeds in these conditions is 50,000 nodule bacteria per one seed. Inoculation should be conducted by a strain with a high competing ability.

Fertilizers↗
PubMed1992

[Assessment of the value of stimulation from a preparation of Tołpa peat for treatment of trauma related osteomyelitis].

Tołpa peat preparation at the dose of 5 mg per day was administered to 10 patients with chronic posttraumatic osteomyelitis for 6 weeks period of time. Good clinical result (ceasing of the inflammatory process) was found in 4 patients but 3 of them were concurrently treated surgically. Immunological examination (angiogenesis test and chemiluminescence test) performed before the onset and after completion of the treatment with Tołpa preparation did not reveal meaningful changes indicating immunomodulating action of the preparation on the course of posttraumatic osteomyelitis.

Adolescent↗
PubMed1997

[Fluorescence spectroscopic analysis of huminite of the peat and soft brown coal].

The huminite of the peat and soft brown coal in the Zhenan basin, western Yunnan, has been studied by means of fluorescence microscopy. The study reveals that the fluorescent features of the huminite are considerabably complicated: some huminite, like liptinites, can give out dark yellow to yellow fluorescent light, I546 ranging from 8.13 to 13.17; and the fluorescent spectrum having one peak or two peaks, lambdamax ranging from 555 to 585nm and Q650/500 from 0.60 to 2.93. Most of huminites do not give out fluorescent light or give out dark brown fluorescent light, I546 ranging from 0 to 5.38. Because of having extraordinarily weak fluorescent light, it is very difficult to obtain their fluorescent spectrum. Nevertherless, after being stimulated for several minutes, some huminites that do not give out fluorescent light or give out dark brown fluorescent light may give out yellowish brown to dark orange fluorescent light, I546 ranging from 6.12 to 12.17, lambdamax. from 590 to 615nm and Q650/600 from 3.49 to 4.31. With the stimulating time becoming longer (10 to 20min), some huminites,may give out sharper yellow fluorescent light, I546 ranging from 12.18 to 20.01, lambdamax from 555 to 595nm and Q650/500 from 0.87 to 1.60.

English Abstract↗
PubMed1998

[A fluorescence photometry study on the suberinite in the shallow burial peat].

A detailed study of the suberinite in the shallow burial peat from Zhenan basin, western Yunnan, has been carried out. The study has revealed that the suberinite is the most unstable maceral among all the stable macerals. It may be oxidized and/or decomposed, resulting in changes in the structure and, especially optical feature. The fluorescence light of the suberinite that has not been oxidized and decomposed is green with I546 ranging from 1.5 to 2.0; and the fluorescence spectrum has one peak: lambda(max) ranging from 480 to 510nm; Q500/650 ranging from 0.12 to 0.26; semi-wave width averaging 150nm. Nevertheless, those suberinites that are oxidized and/or decomposed give off yellow or yellowish brown fluorescent light and the I546 reduces to less than 1, even to 0.05 lambda(max) increases from 580 to 610nm; Q500/560 from 2.75 to 3.31. With illuminating time going by, the fluorescence feature of the suberinite could be changed, mainly in the fluorescence intensity and fluorescence spectrum. The suberinite that has been not oxidized and/or decomposed changes negetively in fluorescence intensity and its fluorescence spectrum moves towards red light wavelength. Nevertheless those suberinites that have been oxidized and/or decomposed change positively in fluorescence intensity and the fluorescent spectrum moves towards blue light wavelength.

English Abstract↗