Leaf Litter Mixtures Alter Microbial Community Development: Mechanisms for Non-Additive Effects in Litter Decomposition

PubMed Central

Chapman, Samantha K.; Newman, Gregory S.; Hart, Stephen C.; Schweitzer, Jennifer A.; Koch, George W.

2013-01-01

To what extent microbial community composition can explain variability in ecosystem processes remains an open question in ecology. Microbial decomposer communities can change during litter decomposition due to biotic interactions and shifting substrate availability. Though relative abundance of decomposers may change due to mixing leaf litter, linking these shifts to the non-additive patterns often recorded in mixed species litter decomposition rates has been elusive, and links community composition to ecosystem function. We extracted phospholipid fatty acids (PLFAs) from single species and mixed species leaf litterbags after 10 and 27 months of decomposition in a mixed conifer forest. Total PLFA concentrations were 70% higher on litter mixtures than single litter types after 10 months, but were only 20% higher after 27 months. Similarly, fungal-to-bacterial ratios differed between mixed and single litter types after 10 months of decomposition, but equalized over time. Microbial community composition, as indicated by principal components analyses, differed due to both litter mixing and stage of litter decomposition. PLFA biomarkers a15∶0 and cy17∶0, which indicate gram-positive and gram-negative bacteria respectively, in particular drove these shifts. Total PLFA correlated significantly with single litter mass loss early in decomposition but not at later stages. We conclude that litter mixing alters microbial community development, which can contribute to synergisms in litter decomposition. These findings advance our understanding of how changing forest biodiversity can alter microbial communities and the ecosystem processes they mediate. PMID:23658639

Microbial activity and community composition during bioremediation of diesel-oil-contaminated soil: effects of hydrocarbon concentration, fertilizers, and incubation time.

PubMed

Margesin, Rosa; Hämmerle, Marion; Tscherko, Dagmar

2007-02-01

We investigated the influence of three factors-diesel oil concentration [2500, 5000, 10,000, 20,000 mg total petroleum hydrocarbons (TPH) kg(-1) soil], biostimulation (unfertilized, inorganic fertilization with NPK nutrients, or oleophilic fertilization with Inipol EAP22), and incubation time-on hydrocarbon removal, enzyme activity (lipase), and microbial community structure [phospholipid fatty acids (PLFA)] in a laboratory soil bioremediation treatment. Fertilization enhanced TPH removal and lipase activity significantly (P < or = 0.001). The higher the initial contamination, the more marked was the effect of fertilization. Differences between the two fertilizers were not significant (P > 0.05). Microbial communities, as assessed by PLFA patterns, were primarily influenced by the TPH content, followed by fertilization, and the interaction of these two factors, whereas incubation time was of minor importance. This was demonstrated by three-factorial analysis of variance and multidimensional scaling analysis. Low TPH content had no significant effect on soil microbial community, independent of the treatment. High TPH content generally resulted in increased PLFA concentrations, whereby a significant increase in microbial biomass with time was only observed with inorganic fertilization, whereas oleophilic fertilization (Inipol EAP22) tended to inhibit microbial activity and to reduce PLFA contents with time. Among bacteria, PLFA indicative of the Gram-negative population were significantly (P < or = 0.05) increased in soil samples containing high amounts of diesel oil and fertilized with NPK after 21-38 days of incubation at 20 degrees C. The Gram-positive population was not significantly influenced by TPH content or biostimulation treatment.

In-Situ 13C-Labeling of Microbial Phospholipid Fatty Acids: Tracing Substrate Assimilation in a Petroleum-Contaminated Aquifer

NASA Astrophysics Data System (ADS)

Pombo, S. A.; Schroth, M. H.; Pelz, O.; Zeyer, J.

2001-12-01

Stable isotope analysis of phospholipid-derived fatty acids (PLFA) is a novel tool to trace assimilation of organic carbon in microbial communities. The 13C-labeling of biomarker fatty acids allows the identification of specific microbial populations involved in the metabolism of particular substrates, supplemented in 13C-labeled form. The goal of this study was to investigate the feasibility of 13C-labeling of PLFA and produced dissolved inorganic carbon (DIC) in a petroleum hydrocarbon (PHC)-contaminated aquifer during an in-situ experiment. To this end, we performed a single-well "push-pull" test in a monitoring well located in the denitrifying zone of a PHC-contaminated aquifer in Studen, Switzerland. During the experiment, we injected 500 L of site groundwater that was amended with 13C-labeled acetate (50% [2-13C]) and nitrate as reactants, and bromide as conservative tracer. Following the injection, we extracted a total of 1000 L of test solution/groundwater mixture after 4, 23 and 46 h from the same location. Concentrations of anions were measured in samples collected during the extraction. From these data, we computed first order rate coefficients for consumption of acetate (0.70 +/- 0.05 1/d) and nitrate (0.63 +/- 0.08 1/d). In addition, we extracted and identified PLFA, and measured \\delta13C values of PLFA and DIC. After only 4 h of incubation, we detected 13C-enrichment of certain PLFA in suspended biomass of extracted groundwater. After 46 h, we measured enrichments of up to 5000 per mil in certain PLFA (e.g. 16:1ω 7c), and up to 1500 per mil in the produced DIC. Our results demonstrate the feasibility of in-situ 13C-labeling of PLFA and DIC using push-pull tests to determine microbial activities in-situ in a natural ecosystem.

Structure of a microbial community in soil after prolonged addition of low levels of simulated acid rain

PubMed

Pennanen; Fritze; Vanhala; Kiikkila; Neuvonen; Baath

1998-06-01

Humus samples were collected 12 growing seasons after the start of a simulated acid rain experiment situated in the subarctic environment. The acid rain was simulated with H2SO4, a combination of H2SO4 and HNO3, and HNO3 at two levels of moderate acidic loads close to the natural anthropogenic pollution levels of southern Scandinavia. The higher levels of acid applications resulted in acidification, as defined by humus chemistry. The concentrations of base cations decreased, while the concentrations of exchangeable H+, Al, and Fe increased. Humus pH decreased from 3.83 to 3.65. Basal respiration decreased with decreasing humus pH, and total microbial biomass, measured by substrate-induced respiration and total amount of phospholipid fatty acids (PLFA), decreased slightly. An altered PLFA pattern indicated a change in the microbial community structure at the higher levels of acid applications. In general, branched fatty acids, typical of gram-positive bacteria, increased in the acid plots. PLFA analysis performed on the bacterial community growing on agar plates also showed that the relative amount of PLFA specific for gram-positive bacteria increased due to the acidification. The changed bacterial community was adapted to the more acidic environment in the acid-treated plots, even though bacterial growth rates, estimated by thymidine and leucine incorporation, decreased with pH. Fungal activity (measured as acetate incorporation into ergosterol) was not affected. This result indicates that bacteria were more affected than fungi by the acidification. The capacity of the bacterial community to utilize 95 different carbon sources was variable and only showed weak correlations to pH. Differences in the toxicities of H2SO4 and HNO3 for the microbial community were not found.

Constraining carbon sources and cycling of endolithic microbial communities in the Atacama Desert

NASA Astrophysics Data System (ADS)

Ziolkowski, L. A.; Slater, G. F.; Davila, A.; Wierzchos, J.

2010-12-01

The Atacama Desert, one of the driest places on Earth, is considered a suitable analog for the extremely arid, oxidizing conditions on the surface of Mars. Recent observations suggest the presence of evaporitic deposits on the surface of Mars, such as those found in the Atacama. Halites in the Atacama have been shown to be hygroscopic and are colonized by photosynthetic microbes. While there is considerable evidence for the decrease in abundance and diversity of microbes closer to the hyper-arid core of the Atacama, experimental studies have thus far have yet to estimate the sources of carbon to these communities and the rate at which they cycle. To address these questions, we characterized the isotopic composition (13C and 14C) microbial community biomarkers from four distinct sites in the Atacama. Sites ranged from halites in the hyper-arid core (Yungay, Salar Grande) to volcanic rock and gypsum near the Monturaqui Crater. Our analysis of the phospholipids fatty acids (PLFA) and glycolipid fatty acid (GLFA) methyl esters of the endoliths agreed with previous studies: the abundance and diversity of microbes decreases approaching the hyper-arid core. The total PLFA and GLFA concentrations were lower at Yungay than Salar Grande and higher in the gypsum and volcanic rock samples. Changes in the mole percentage distribution of the PLFA and GLFA illustrated that the endolithic communities inhabiting the volcanic rock and gypsum were more complex than those inhabiting the halites. ∂13C of both PLFA and GLFA showed that non-halite lipids were less depleted in 13C than halite-lipids. This suggested a difference in carbon source or cycling. The 14C content of PLFA and GLFA varied by up to 250 per mil. Endolith PLFA and GLFA from the gypsum had radiocarbon signatures comparable to the modern atmosphere, which suggests that the predominant source of carbon to the system is the modern atmosphere and that lipids are cycling rapidly in this system. However, at the other three locations both PLFA and GLFA were more depleted in 14C relative to the gypsum, indicative of a difference in carbon sources and cycling. This may relate to the presence of inputs of older carbon to these endolithic environments, or to the persistence of biosignature compounds for significant lengths of time notwithstanding the generally oxidizing nature of the Atacama environment. This persistence may be related to differences in moisture levels and therefore hydrolysis of these compounds. Applied to Mars, our results suggest the potential that biosignatures of photosynthesis may be preserved in low-moisture, high salt endolithic environments. Ongoing work to understand the sources of isotopic variation within the Atacama analogue system will help identify the potential for target biosignatures in similar systems on Mars.

Microbial Substrate Usage Indicated by C-14 Contents of Phospholipid Fatty Acids From Soil Organic Matter

NASA Astrophysics Data System (ADS)

Rethemeyer, J.; Nadeau, M. J.; Grootes, P. M.; Kramer, C.; Gleixner, G.

2004-05-01

Phospholipid fatty acids (PLFA's) are generally associated with viable (bacterial) cell membranes. They are thought to be short-lived under normal soil conditions. We compare the C-14 levels in PLFA's obtained from soil samples from the,clean" experimental site at Rotthalmünster (Germany) with those from the agricultural research station at Halle (Germany), where the soil is contaminated with,old" carbon from lignite mining and industry. The most abundant PLFA's were isolated via preparative capillary gas chromatography of their methyl-esters at the Max-Planck Institute, Jena, and their C-14 concentration was determined via accelerator mass spectrometry at the Leibniz-Labor, Kiel. The C-14 levels of three mono-unsaturated fatty acids (n-C17:1, n-C18:1 (and n-C16:1)) are not statistically significant different from those of the contemporaneous atmosphere, indicating these fatty acids were derived from fresh plant material. C-14 levels significantly above those of the atmosphere in three saturated fatty acids (i/a-C15:0, n-C16:0 and cy-C18:0) from the surface soil of Rotthalmünster must derive from carbon fixed from the atmosphere several years earlier, when levels of bomb-C-14, remaining from the atmospheric nuclear weapons tests, especially of the early 1960's, were still higher. Lower C-14 levels in the same compounds from the Halle surface soil indicate the incorporation of "old" contaminant carbon. A below- atmospheric C-14 concentration in n-C18:0 in Rotthalmünster surface soil may reflect the partial incorporation of carbon from older, pre-bomb times. The C-14 concentrations show these PLFA's were synthesized predominantly from recent to sub-recent photosynthetic compounds, while the significant differences in C-14 concentration, observed between the PLFA's, indicate their production from soil organic matter fractions of different (recent) age and C-14 content. The Halle results show "old" carbon may be incorporated into PLFA's and thus reenter the soil carbon cycle.

Priming alters soil carbon dynamics during forest succession

NASA Astrophysics Data System (ADS)

Qiao, Na; Xu, Xingliang; Wang, Juan; Kuzyakov, Yakov

2017-04-01

The mechanisms underlying soil carbon (C) dynamics during forest succession remain challenged. We examined priming of soil organic matter (SOM) decomposition along a vegetation succession: grassland, young and old-growth forests. Soil C was primed much more strongly in young secondary forest than in grassland or old-growth forest. Priming resulted in large C losses (negative net C balance) in young-forest soil, whereas C stocks increased in grassland and old-growth forest. Microbial composition assessed by phospholipid fatty acids (PLFA) and utilization of easily available organics (13C-PLFA) indicate that fungi were responsible for priming in young-forest soils. Consequently, labile C inputs released by litter decomposition and root exudation determine microbial functional groups that decompose SOM during forest succession. These findings provide novel insights into connections between SOM dynamics and stabilization with microbial functioning during forest succession and show that priming is an important mechanism for contrasting soil C dynamics in young and old-growth forests.

Soil microbial community structure and function responses to successive planting of Eucalyptus.

PubMed

Chen, Falin; Zheng, Hua; Zhang, Kai; Ouyang, Zhiyun; Li, Huailin; Wu, Bing; Shi, Qian

2013-10-01

Many studies have shown soil degradation after the conversion of native forests to exotic Eucalyptus plantations. However, few studies have investigated the long-term impacts of short-rotation forestry practices on soil microorganisms. The impacts of Eucalyptus successive rotations on soil microbial communities were evaluated by comparing phospholipid fatty acid (PLFA) abundances, compositions, and enzyme activities of native Pinus massoniana plantations and adjacent 1st, 2nd, 3rd, 4th generation Eucalyptus plantations. The conversion from P. massoniana to Eucalyptus plantations significantly decreased soil microbial community size and enzyme activities, and increased microbial physiological stress. However, the PLFA abundances formed "u" shaped quadratic functions with Eucalyptus plantation age. Alternatively, physiological stress biomarkers, the ratios of monounsaturated to saturated fatty acid and Gram+ to Gram- bacteria, formed "n"' shaped quadratic functions, and the ratio of cy17:0 to 16:1omega7c decreased with plantation age. The activities of phenol oxidase, peroxidase, and acid phosphatase increased with Eucalyptus plantation age, while the cellobiohydrolase activity formed "u" shaped quadratic functions. Soil N:P, alkaline hydrolytic nitrogen, soil organic carbon, and understory cover largely explained the variation in PLFA profiles while soil N:P, alkaline hydrolytic nitrogen, and understory cover explained most of the variability in enzyme activity. In conclusion, soil microbial structure and function under Eucalyptus plantations were strongly impacted by plantation age. Most of the changes could be explained by altered soil resource availability and understory cover associated with successive planting of Eucalyptus. Our results highlight the importance of plantation age for assessing the impacts of plantation conversion as well as the importance of reducing disturbance for plantation management.

Pasture degradation modifies soil organic matter properties and biochemical functioning in Tibetan grasslands

NASA Astrophysics Data System (ADS)

Spielvogel, Sandra; Steingräber, Laura; Schleuß, Per; Kuzyakov, Yakov; Guggenberger, Georg

2015-04-01

Kobresia pastures of the Tibetan Plateau represent the world's largest alpine ecosystem. Moderate husbandry on Kobresia pastures is beneficial for the storage of soil organic carbon (OC), nitrogen (N) and other nutrients and prevents erosion by establishment of sedge-turf root mats with high OC allocation rates below ground. However, undisturbed root mats are affected by freezing and thawing processes, which cause initial ice cracks. As a consequence decomposition of root mat layers will be accelerated and current sedentarization programs with concomitant increased grazing intensity may additionally enhance root mat degradation. Finally, cracks are enlarged by water and wind erosion as well as pika activities until bare soil surface areas without root mat horizons occur. The aim of this study was to understand the impact of the root mat layer on soil organic carbon stabilization and microbial functioning depending on soil depths and to predict future changes (OC, N and nutrient losses, soil microbial functioning in SOM transformation) by overgrazing and climate change. We investigated the mineral soil below Kobresia root mats along a false time degradation sequence ranging from stage 1 (intact root mat) to stage 4 (mats with large cracks and bare soil patches). Vertical gradients of δ13C values, neutral sugar, cutin and suberin contents as well as microbial biomass estimated by total phospholipid fatty acid (PLFA), microbial community composition (PLFA profiles) and activities of six extracellular enzymes involved in the C, N, and P cycle were assessed. Soil OC and N contents as well as C/N ratios indicate an increasing illuviation of topsoil material into the subsoil with advancing root mat degradation. This was confirmed by more negative δ13C values as well as significantly (p ≤ 0.05) increasing contributions of cutin derived hydroxy fatty acids to OC in the subsoils from degradation stages 1 to 4. PLFA profiles were surprisingly similar in the subsoils of degradation stages 1, 2 and 3 although OC contents and composition in the subsoil changed progressively from stage 1 to 4. Only the PLFA profiles of stage 4 differed from those of the other subsoils, suggesting that microbial communities were mainly controlled by other factors than C and N contents and SOM composition. These findings were also confirmed by the activities of β-glucosidase, xylanase, amino-peptidases and proteases. Those enzyme activities were highest in the subsoil of degradation stage 4, whereas degradation stages 2 and 3 showed low enzyme activities in the subsoil if related to soil OC amount and composition. We conclude that pasture degradation decreases not only mechanical protection of soil surface by Kobresia root mats, but also changes their biochemical and microbial functions.

Comparison of whole-cell fatty acid (MIDI) or phospholipid fatty acid (PLFA) extractants as biomarkers to profile soil microbial communities.

PubMed

Fernandes, Marcelo F; Saxena, Jyotisna; Dick, Richard P

2013-07-01

The whole-cell lipid extraction to profile microbial communities on soils using fatty acid (FA) biomarkers is commonly done with the two extractants associated with the phospholipid fatty acid (PLFA) or Microbial IDentification Inc. (MIDI) methods. These extractants have very different chemistry and lipid separation procedures, but often shown a similar ability to discriminate soils from various management and vegetation systems. However, the mechanism and the chemistry of the exact suite of FAs extracted by these two methods are poorly understood. Therefore, the objective was to qualitatively and quantitatively compare the MIDI and PLFA microbial profiling methods for detecting microbial community shifts due to soil type or management. Twenty-nine soil samples were collected from a wide range of soil types across Oregon and extracted FAs by each method were analyzed by gas chromatography (GC) and GC-mass spectrometry. Unlike PLFA profiles, which were highly related to microbial FAs, the overall MIDI-FA profiles were highly related to the plant-derived FAs. Plant-associated compounds were quantitatively related to particulate organic matter (POM) and qualitatively related to the standing vegetation at sampling. These FAs were negatively correlated to respiration rate normalized to POM (RespPOM), which increased in systems under more intensive management. A strong negative correlation was found between MIDI-FA to PLFA ratios and total organic carbon (TOC). When the reagents used in MIDI procedure were tested for the limited recovery of MIDI-FAs from soil with high organic matter, the recovery of MIDI-FA microbial signatures sharply decreased with increasing ratios of soil to extractant. Hence, the MIDI method should be used with great caution for interpreting changes in FA profiles due to shifts in microbial communities.

Elucidating carbon sources driving microbial metabolism during oil sands reclamation.

PubMed

Bradford, Lauren M; Ziolkowski, Lori A; Goad, Corey; Warren, Lesley A; Slater, Gregory F

2017-03-01

Microbial communities play key roles in remediation and reclamation of contaminated environments via biogeochemical cycling of organic and inorganic components. Understanding the trends in in situ microbial community abundance, metabolism and carbon sources is therefore a crucial component of effective site management. The focus of this study was to use radiocarbon analysis to elucidate the carbon sources driving microbial metabolism within the first pilot wetland reclamation project in the Alberta oil sands region where the observation of H 2 S had indicated the occurrence of microbial sulphate reduction. The reclamation project involved construction of a three compartment system consisting of a freshwater wetland on top of a sand cap overlying a composite tailings (CT) deposit. Radiocarbon analysis demonstrated that both dissolved and sediment associated organic carbon associated with the deepest compartments (the CT and sand cap) was primarily fossil (Δ 14 C = -769 to -955‰) while organic carbon in the overlying peat was hundreds to thousands of years old (Δ 14 C = -250 to -350‰). Radiocarbon contents of sediment associated microbial phospholipid fatty acids (PLFA) were consistent with the sediment bulk organic carbon pools (Peat: Δ 14 C PLFA  = -257‰; Sand cap Δ 14 C PLFA  = -805‰) indicating that these microbes were using sediment associated carbon. In contrast, microbial PLFA grown on biofilm units installed in wells within the deepest compartments contained much more modern carbon that the associated bulk carbon pools. This implied that the transfer of relatively more modern carbon was stimulating the microbial community at depth within the system. Correlation between cellular abundance estimates based on PLFA concentrations and the Δ 14 C PLFA indicated that the utilization of this more modern carbon was stimulating the microbial community at depth. These results highlight the importance of understanding the occurrence and potential outcomes of the introduction of relatively bioavailable carbon to mine wastes in order to predict and manage the performance of reclamation strategies. Copyright © 2016 Elsevier Ltd. All rights reserved.

Near infrared spectroscopy for determination of various physical, chemical and biochemical properties in Mediterranean soils.

PubMed

Zornoza, R; Guerrero, C; Mataix-Solera, J; Scow, K M; Arcenegui, V; Mataix-Beneyto, J

2008-07-01

The potential of near infrared (NIR) reflectance spectroscopy to predict various physical, chemical and biochemical properties in Mediterranean soils from SE Spain was evaluated. Soil samples (n=393) were obtained by sampling thirteen locations during three years (2003-2005 period). These samples had a wide range of soil characteristics due to variations in land use, vegetation cover and specific climatic conditions. Biochemical properties also included microbial biomarkers based on phospholipid fatty acids (PLFA). Partial least squares (PLS) regression with cross validation was used to establish relationships between the NIR spectra and the reference data from physical, chemical and biochemical analyses. Based on the values of coefficient of determination (r(2)) and the ratio of standard deviation of validation set to root mean square error of cross validation (RPD), predicted results were evaluated as excellent (r(2)>0.90 and RPD>3) for soil organic carbon, Kjeldahl nitrogen, soil moisture, cation exchange capacity, microbial biomass carbon, basal soil respiration, acid phosphatase activity, β-glucosidase activity and PLFA biomarkers for total bacteria, Gram positive bacteria, actinomycetes, vesicular-arbuscular mycorrhizal fungi and total PLFA biomass. Good predictions (0.81

Diversity, composition, and geographical distribution of microbial communities in California salt marsh sediments

USGS Publications Warehouse

Cordova-Kreylos, A. L.; Cao, Y.; Green, P.G.; Hwang, H.-M.; Kuivila, K.M.; LaMontagne, M.G.; Van De Werfhorst, L. C.; Holden, P.A.; Scow, K.M.

2006-01-01

The Pacific Estuarine Ecosystem Indicators Research Consortium seeks to develop bioindicators of toxicant-induced stress and bioavailability for wetland biota. Within this framework, the effects of environmental and pollutant variables on microbial communities were studied at different spatial scales over a 2-year period. Six salt marshes along the California coastline were characterized using phospholipid fatty acid (PLFA) analysis and terminal restriction fragment length polymorphism (TRFLP) analysis. Additionally, 27 metals, six currently used pesticides, total polychlorinated biphenyls and polycyclic aromatic hydrocarbons, chlordanes, nonachlors, dichlorodiphenyldichloroethane, and dichlorodiphenyldichloroethylene were analyzed. Sampling was performed over large (between salt marshes), medium (stations within a marsh), and small (different channel depths) spatial scales. Regression and ordination analysis suggested that the spatial variation in microbial communities exceeded the variation attributable to pollutants. PLFA analysis and TRFLP canonical correspondence analysis (CCA) explained 74 and 43% of the variation, respectively, and both methods attributed 34% of the variation to tidal cycles, marsh, year, and latitude. After accounting for spatial variation using partial CCA, we found that metals had a greater effect on microbial community composition than organic pollutants had. Organic carbon and nitrogen contents were positively correlated with PLFA biomass, whereas total metal concentrations were positively correlated with biomass and diversity. Higher concentrations of heavy metals were negatively correlated with branched PLFAs and positively correlated with methyl- and cyclo-substituted PLFAs. The strong relationships observed between pollutant concentrations and some of the microbial indicators indicated the potential for using microbial community analyses in assessments of the ecosystem health of salt marshes. Copyright ?? 2006, American Society for Microbiology. All Rights Reserved.

Diversity, Composition, and Geographical Distribution of Microbial Communities in California Salt Marsh Sediments

PubMed Central

Córdova-Kreylos, Ana Lucía; Cao, Yiping; Green, Peter G.; Hwang, Hyun-Min; Kuivila, Kathryn M.; LaMontagne, Michael G.; Van De Werfhorst, Laurie C.; Holden, Patricia A.; Scow, Kate M.

2006-01-01

The Pacific Estuarine Ecosystem Indicators Research Consortium seeks to develop bioindicators of toxicant-induced stress and bioavailability for wetland biota. Within this framework, the effects of environmental and pollutant variables on microbial communities were studied at different spatial scales over a 2-year period. Six salt marshes along the California coastline were characterized using phospholipid fatty acid (PLFA) analysis and terminal restriction fragment length polymorphism (TRFLP) analysis. Additionally, 27 metals, six currently used pesticides, total polychlorinated biphenyls and polycyclic aromatic hydrocarbons, chlordanes, nonachlors, dichlorodiphenyldichloroethane, and dichlorodiphenyldichloroethylene were analyzed. Sampling was performed over large (between salt marshes), medium (stations within a marsh), and small (different channel depths) spatial scales. Regression and ordination analysis suggested that the spatial variation in microbial communities exceeded the variation attributable to pollutants. PLFA analysis and TRFLP canonical correspondence analysis (CCA) explained 74 and 43% of the variation, respectively, and both methods attributed 34% of the variation to tidal cycles, marsh, year, and latitude. After accounting for spatial variation using partial CCA, we found that metals had a greater effect on microbial community composition than organic pollutants had. Organic carbon and nitrogen contents were positively correlated with PLFA biomass, whereas total metal concentrations were positively correlated with biomass and diversity. Higher concentrations of heavy metals were negatively correlated with branched PLFAs and positively correlated with methyl- and cyclo-substituted PLFAs. The strong relationships observed between pollutant concentrations and some of the microbial indicators indicated the potential for using microbial community analyses in assessments of the ecosystem health of salt marshes. PMID:16672478

Membrane Lipids as Indicators for Viable Bacterial Communities Inhabiting Petroleum Systems.

PubMed

Gruner, Andrea; Mangelsdorf, Kai; Vieth-Hillebrand, Andrea; Horsfield, Brian; van der Kraan, Geert M; Köhler, Thomas; Janka, Christoph; Morris, Brandon E L; Wilkes, Heinz

2017-08-01

Microbial activity in petroleum reservoirs has been implicated in a suite of detrimental effects including deterioration of petroleum quality, increases in oil sulfur content, biofouling of steel pipelines and other infrastructures, and well plugging. Here, we present a biogeochemical approach, using phospholipid fatty acids (PLFAs), for detecting viable bacteria in petroleum systems. Variations within the bacterial community along water flow paths (producing well, topside facilities, and injection well) can be elucidated in the field using the same technique, as shown here within oil production plants in the Molasse Basin of Upper Austria. The abundance of PLFAs is compared to total cellular numbers, as detected by qPCR of the 16S rDNA gene, to give an overall comparison between the resolutions of both methods in a true field setting. Additionally, the influence of biocide applications on lipid- and DNA-based quantification was investigated. The first oil field, Trattnach, showed significant PLFA abundances and cell numbers within the reservoir and topside facilities. In contrast, the second field (Engenfeld) showed very low PLFA levels overall, likely due to continuous treatment of the topside facilities with a glutaraldehyde-based antimicrobial. In comparison, Trattnach is dosed once per week in a batch fashion. Changes within PLFA compositions across the flow path, throughout the petroleum production plants, point to cellular adaptation within the system and may be linked to shifts in the dominance of certain bacterial types in oil reservoirs versus topside facilities. Overall, PLFA-based monitoring provides a useful tool to assess the abundance and high-level taxonomic diversity of viable microbial populations in oil production wells, topside infrastructure, pipelines, and other related facilities.

Key Edaphic Properties Largely Explain Temporal and Geographic Variation in Soil Microbial Communities across Four Biomes.

PubMed

Docherty, Kathryn M; Borton, Hannah M; Espinosa, Noelle; Gebhardt, Martha; Gil-Loaiza, Juliana; Gutknecht, Jessica L M; Maes, Patrick W; Mott, Brendon M; Parnell, John Jacob; Purdy, Gayle; Rodrigues, Pedro A P; Stanish, Lee F; Walser, Olivia N; Gallery, Rachel E

2015-01-01

Soil microbial communities play a critical role in nutrient transformation and storage in all ecosystems. Quantifying the seasonal and long-term temporal extent of genetic and functional variation of soil microorganisms in response to biotic and abiotic changes within and across ecosystems will inform our understanding of the effect of climate change on these processes. We examined spatial and seasonal variation in microbial communities based on 16S rRNA gene sequencing and phospholipid fatty acid (PLFA) composition across four biomes: a tropical broadleaf forest (Hawaii), taiga (Alaska), semiarid grassland-shrubland (Utah), and a subtropical coniferous forest (Florida). In this study, we used a team-based instructional approach leveraging the iPlant Collaborative to examine publicly available National Ecological Observatory Network (NEON) 16S gene and PLFA measurements that quantify microbial diversity, composition, and growth. Both profiling techniques revealed that microbial communities grouped strongly by ecosystem and were predominately influenced by three edaphic factors: pH, soil water content, and cation exchange capacity. Temporal variability of microbial communities differed by profiling technique; 16S-based community measurements showed significant temporal variability only in the subtropical coniferous forest communities, specifically through changes within subgroups of Acidobacteria. Conversely, PLFA-based community measurements showed seasonal shifts in taiga and tropical broadleaf forest systems. These differences may be due to the premise that 16S-based measurements are predominantly influenced by large shifts in the abiotic soil environment, while PLFA-based analyses reflect the metabolically active fraction of the microbial community, which is more sensitive to local disturbances and biotic interactions. To address the technical issue of the response of soil microbial communities to sample storage temperature, we compared 16S-based community structure in soils stored at -80°C and -20°C and found no significant differences in community composition based on storage temperature. Free, open access datasets and data sharing platforms are powerful tools for integrating research and teaching in undergraduate and graduate student classrooms. They are a valuable resource for fostering interdisciplinary collaborations, testing ecological theory, model development and validation, and generating novel hypotheses. Training in data analysis and interpretation of large datasets in university classrooms through project-based learning improves the learning experience for students and enables their use of these significant resources throughout their careers.

Key Edaphic Properties Largely Explain Temporal and Geographic Variation in Soil Microbial Communities across Four Biomes

PubMed Central

Borton, Hannah M.; Espinosa, Noelle; Gebhardt, Martha; Gil-Loaiza, Juliana; Gutknecht, Jessica L. M.; Maes, Patrick W.; Mott, Brendon M.; Parnell, John Jacob; Purdy, Gayle; Rodrigues, Pedro A. P.; Stanish, Lee F.; Walser, Olivia N.

2015-01-01

Soil microbial communities play a critical role in nutrient transformation and storage in all ecosystems. Quantifying the seasonal and long-term temporal extent of genetic and functional variation of soil microorganisms in response to biotic and abiotic changes within and across ecosystems will inform our understanding of the effect of climate change on these processes. We examined spatial and seasonal variation in microbial communities based on 16S rRNA gene sequencing and phospholipid fatty acid (PLFA) composition across four biomes: a tropical broadleaf forest (Hawaii), taiga (Alaska), semiarid grassland-shrubland (Utah), and a subtropical coniferous forest (Florida). In this study, we used a team-based instructional approach leveraging the iPlant Collaborative to examine publicly available National Ecological Observatory Network (NEON) 16S gene and PLFA measurements that quantify microbial diversity, composition, and growth. Both profiling techniques revealed that microbial communities grouped strongly by ecosystem and were predominately influenced by three edaphic factors: pH, soil water content, and cation exchange capacity. Temporal variability of microbial communities differed by profiling technique; 16S-based community measurements showed significant temporal variability only in the subtropical coniferous forest communities, specifically through changes within subgroups of Acidobacteria. Conversely, PLFA-based community measurements showed seasonal shifts in taiga and tropical broadleaf forest systems. These differences may be due to the premise that 16S-based measurements are predominantly influenced by large shifts in the abiotic soil environment, while PLFA-based analyses reflect the metabolically active fraction of the microbial community, which is more sensitive to local disturbances and biotic interactions. To address the technical issue of the response of soil microbial communities to sample storage temperature, we compared 16S-based community structure in soils stored at -80°C and -20°C and found no significant differences in community composition based on storage temperature. Free, open access datasets and data sharing platforms are powerful tools for integrating research and teaching in undergraduate and graduate student classrooms. They are a valuable resource for fostering interdisciplinary collaborations, testing ecological theory, model development and validation, and generating novel hypotheses. Training in data analysis and interpretation of large datasets in university classrooms through project-based learning improves the learning experience for students and enables their use of these significant resources throughout their careers. PMID:26536666

Abnormal octadeca-carbon fatty acids distribution in erythrocyte membrane phospholipids of patients with gastrointestinal tumor.

PubMed

Lin, Shaohui; Li, Tianyu; Liu, Xifang; Wei, Shihu; Liu, Zequn; Hu, Shimin; Liu, Yali; Tan, Hongzhuan

2017-06-01

Fatty acid (FA) composition is closely associated with tumorigenesis and neoplasm metastasis. This study was designed to investigate the differences of phospholipid FA (PLFA) composition in erythrocyte and platelet cell membranes in both gastrointestinal (GI) tumor patients and healthy controls.In this prospective study, 50 GI tumor patients and 33 healthy volunteers were recruited between the years 2013 and 2015. Blood samples were collected from healthy volunteers and patients, and FA composition was assessed using gas chromatography-mass spectrometer (GC-MS), and data were analyzed by multifactor regression analysis.Compared with healthy controls, the percentages of C18:0 (stearic acid, SA), C22:6 (docosahexaenoic acid, DHA), and n-3 polyunsaturated FAs (n-3 PUFA) were significantly increased, while C18:1 (oleic acid, OA), C18:2 (linoleic acid, LA), and monounsaturated FAs (MUFA) decreased in erythrocyte membranes of GI tumor patients. Also, patient's platelets revealed higher levels of C20:4 (arachidonic acid, AA) and DHA, and lower levels of OA and MUFA.Our study displayed a remarkable change in the FA composition of erythrocyte and platelet membranes in GI tumor patients as compared with healthy controls. The octadeca-carbon FAs (SA, OA, and LA) in erythrocyte membranes could serve as a potential indicator for GI tumor detection.

Distance-dependent varieties of microbial community structure and metabolic functions in the rhizosphere of Sedum alfredii Hance during phytoextraction of a cadmium-contaminated soil.

PubMed

Yang, Wenhao; Zhang, Taoxiang; Lin, Sen; Ni, Wuzhong

2017-06-01

The recovery of microbial community and activities is crucial to the remediation of contaminated soils. Distance-dependent variations of microbial community composition and metabolic characteristics in the rhizospheric soil of hyperaccumulator during phytoextraction are poorly understood. A 12-month phytoextraction experiment with Sedum alfredii in a Cd-contaminated soil was conducted. A pre-stratified rhizobox was used for separating sub-layer rhizospheric (0-2, 2-4, 4-6, 6-8, 8-10 mm from the root mat)/bulk soils. Soil microbial structure and function were analyzed by phospholipid fatty acid (PLFA) and MicroResp™ methods. The concentrations of total and specified PLFA biomarkers and the utilization rates for the 14 substrates (organic carbon) in the 0-2-mm sub-layer rhizospheric soil were significantly increased, as well as decreased with the increase in the distance from the root mat. Microbial structure measured by the ratios of different groups of PLFAs such as fungal/bacterial, monounsaturated/saturated, ratios of Gram-positive to Gram-negative (GP/GN) bacterial, and cyclopropyl/monoenoic precursors and 19:0 cyclo/18:1ω7c were significantly changed in the 0-2-mm soil. The PLFA contents and substrate utilization rates were negatively correlated with pH and total, acid-soluble, and reducible fractions of Cd, while positively correlated with labile carbon. The dynamics of microbial community were likely due to root exudates and Cd uptake by S. alfredii. This study revealed the stimulations and gradient changes of rhizosphere microbial community through phytoextraction, as reduced Cd concentration, pH, and increased labile carbons are due to the microbial community responses.

Distinctive Sediment and Adjacent Groundwater Microbial Communities in Bangladesh Aquifers Suggested Through Microbial Lipid Distribution and δ13C Analysis

NASA Astrophysics Data System (ADS)

Martin, K. J. W.; van Geen, A.; Bostick, B. C.; Mailloux, B. J.; Ahmed, K. M.; Choudhury, I.; Slater, G.

2016-12-01

Arsenic groundwater contamination throughout shallow aquifer sediments in Southern Asia has resulted in a large-scale human health crisis. There is a strong consensus that microbial iron reduction coupled to organic carbon oxidation is the predominant mechanism driving this arsenic release. However, limited research has examined the composition and functioning of the indigenous microbial communities. Further, such research has varied between studies targeting microbial communities associated with groundwater versus those associated with sediments. The overall aim of this research study was to use microbial lipid biomarkers of bacterial and micro-eukaryal (phospholipid fatty acids (PLFA)) and archaea (di- and tetra- bound ether lipids) distributions and δ13C analysis to compare the indigenous sedimentary-associated microbial communities with the groundwater-associated microbial communities in Bangladesh aquifers. Field sampling was carried out at four locations (Site B, F, SAM and CAT) in the Araihazar Upazila, Bangladesh in 2013 and 2015. A significant difference (p<0.00001) was found between the cell abundances in the groundwater-associated (2.8 x 101 to 3.0 x 102 cells/mL) (n=9) and the sediment-associated communities (averaging 1.1 x 107 cells/gram (n=19). Long-chain fatty acid methyl esters (FAME's) (C22-C29) derived from micro-eukaryotes were present in the sediments of both Site B and F comprising up to 17 % and 7% (mole %) of the total FAME distribution respectively but not detected in any of the groundwater filters. Shallow Site B sedimentary PLFA showed a progressive depletion in δ13C with depth from -24 to -31 ‰, whereas Site F sedimentary PLFA from similar depths did not show the same trend. Groundwater PLFA from Site B (14 m) contained FAME 18:1 with an average δ13C of -41‰, possibly indicating methanogenic activity (methanogen lipid analysis is ongoing). The results of this study highly suggests that Bangaldesh aquifer sediment and groundwater microbial communties are distinctive and cannot be used interchangably within future research studies investigating microbal arsenic release in these systems.

[Ozone effects on soil microbial community of rice investigated by 13C isotope labeling].

PubMed

Chen, Zhan; Wang, Xiao-Ke; Shang, He

2014-10-01

This study was initiated to explore the effects of dynamic ozone (O3) exposure on soil microbial biomass and phospholipid fatty acids (PLFAs) under potted rice. A pulse-chase labeling experiment was designed to expose potted rice with 13CO2 for 6 h after one and two months, the rice were fumigated by elevated O3 concentration with an 8 h mean of 110 nL · L(-1) (O3). The allocation of the assimilated 13C to soil microorganisms was estimated by analyzing the 13C profile of microbial phospholipid fatty acids (PLFAs). After one month O3 exposure, the soil microbial biomass carbon was not affected, while the 13C-microbial biomass was significantly decreased with elevated O3. Both the total and 13C microbial biomass carbon was remarkably lower than that of control treatment after two months O3 exposure. Principal components analysis of 13C-PLFA data showed that elevated O3 significantly changed soil microbial structure after two month exposures, while there was no difference of 13C-PLFA structure between control and elevated O3 treatments after one month exposure. Δδ13C per hundred thousand of individual PLFA was significantly affected by O3 after both one and two month exposures. Only did ozone change the relative abundance of individual 13C-PLFA (13C%) of bacterial fatty acids after one month exposure, while after two month exposures, the 13C% of fungal and actinomycetic fatty acids were markedly changed by elevated O3.

Effects of Different Organic Manures on the Biochemical and Microbial Characteristics of Albic Paddy Soil in a Short-Term Experiment

PubMed Central

Zhang, Qian; Zhou, Wei; Liang, Guoqing; Wang, Xiubin; Sun, Jingwen; He, Ping; Li, Lujiu

2015-01-01

This study aimed to evaluate the effects of chemical fertilizer (NPK), NPK with livestock manure (NPK+M), NPK with straw (NPK+S), and NPK with green manure (NPK+G) on soil enzyme activities and microbial characteristics of albic paddy soil, which is a typical soil with low productivity in China. The responses of extracellular enzyme activities and the microbial community diversity (determined by phospholipid fatty acid analysis [PLFA] and denaturing gradient gel electrophoresis [DGGE]) were measured. The results showed that NPK+M and NPK+S significantly increased rice yield, with NPK+M being approximately 24% greater than NPK. The NPK+M significantly increased soil organic carbon (SOC) and available phosphate (P) and enhanced phosphatase, β-cellobiosidase, L-leucine aminopeptidase and urease activities. The NPK+S significantly increased SOC and available potassium (K) and significantly enhanced N-acetyl-glucosamidase, β-xylosidase, urease, and phenol oxidase activities. The NPK+G significantly improved total nitrogen (N), ammonium N, available P, and N-acetyl-glucosamidase activity. The PLFA biomass was highest under NPK+S, followed by NPK+M and NPK+G treatments. Principal component analysis (PCA) of the PLFA indicated that soils with NPK+M and NPK+S contained higher proportions of unsaturated and cyclopropane fatty acids (biomarkers of fungi and gram-negative bacteria) and soil under NPK+G contained more straight chain saturated fatty acids (representing gram-positive bacteria). PCA of the DGGE patterns showed that organic amendments had a greater influence on fungal community. Cluster analysis of fungal DGGE patterns revealed that NPK+G was clearly separated. Meanwhile, the bacterial community of NPK+M treatment was the most distinct. RDA analysis revealed changes of microbial community composition mostly depended on β-xylosidase, β-cellobiosidase activities, total N and available K contents. The abundances of gram-negative bacterial and fungal PLFAs probably effective in improving fertility of low-yield albic paddy soil because of their significant influence on DGGE profile. PMID:25879759

Effects of different organic manures on the biochemical and microbial characteristics of albic paddy soil in a short-term experiment.

PubMed

Zhang, Qian; Zhou, Wei; Liang, Guoqing; Wang, Xiubin; Sun, Jingwen; He, Ping; Li, Lujiu

2015-01-01

This study aimed to evaluate the effects of chemical fertilizer (NPK), NPK with livestock manure (NPK+M), NPK with straw (NPK+S), and NPK with green manure (NPK+G) on soil enzyme activities and microbial characteristics of albic paddy soil, which is a typical soil with low productivity in China. The responses of extracellular enzyme activities and the microbial community diversity (determined by phospholipid fatty acid analysis [PLFA] and denaturing gradient gel electrophoresis [DGGE]) were measured. The results showed that NPK+M and NPK+S significantly increased rice yield, with NPK+M being approximately 24% greater than NPK. The NPK+M significantly increased soil organic carbon (SOC) and available phosphate (P) and enhanced phosphatase, β-cellobiosidase, L-leucine aminopeptidase and urease activities. The NPK+S significantly increased SOC and available potassium (K) and significantly enhanced N-acetyl-glucosamidase, β-xylosidase, urease, and phenol oxidase activities. The NPK+G significantly improved total nitrogen (N), ammonium N, available P, and N-acetyl-glucosamidase activity. The PLFA biomass was highest under NPK+S, followed by NPK+M and NPK+G treatments. Principal component analysis (PCA) of the PLFA indicated that soils with NPK+M and NPK+S contained higher proportions of unsaturated and cyclopropane fatty acids (biomarkers of fungi and gram-negative bacteria) and soil under NPK+G contained more straight chain saturated fatty acids (representing gram-positive bacteria). PCA of the DGGE patterns showed that organic amendments had a greater influence on fungal community. Cluster analysis of fungal DGGE patterns revealed that NPK+G was clearly separated. Meanwhile, the bacterial community of NPK+M treatment was the most distinct. RDA analysis revealed changes of microbial community composition mostly depended on β-xylosidase, β-cellobiosidase activities, total N and available K contents. The abundances of gram-negative bacterial and fungal PLFAs probably effective in improving fertility of low-yield albic paddy soil because of their significant influence on DGGE profile.

Shifts in microbial community composition following surface application of dredged river sediments.

PubMed

Baniulyte, Dovile; Favila, Emmanuel; Kelly, John J

2009-01-01

Sediment input to the Illinois River has drastically decreased river depth and reduced habitats for aquatic organisms. Dredging is being used to remove sediment from the Illinois River, and the dredged sediment is being applied to the surface of a brownfield site in Chicago with the goal of revegetating the site. In order to determine the effects of this drastic habitat change on sediment microbial communities, we examined sediment physical, chemical, and microbial characteristics at the time of sediment application to the soil surface as well as 1 and 2 years after application. Microbial community biomass was determined by measurement of lipid phosphate. Microbial community composition was assessed using phospholipid fatty acid (PLFA) analysis, terminal restriction fragment length polymorphism (T-RFLP) analysis of 16S rRNA genes, and clone library sequencing of 16S rRNA genes. Results indicated that the moisture content, organic carbon, and total nitrogen content of the sediment all decreased over time. Total microbial biomass did not change over the course of the study, but there were significant changes in the composition of the microbial communities. PLFA analysis revealed relative increases in fungi, actinomycetes, and Gram positive bacteria. T-RFLP analysis indicated a significant shift in bacterial community composition within 1 year of application, and clone library analysis revealed relative increases in Proteobacteria, Gemmatimonadetes, and Bacteriodetes and relative decreases in Acidobacteria, Spirochaetes, and Planctomycetes. These results provide insight into microbial community shifts following land application of dredged sediment.

The Effects of Mineral Matrices and Extraction Method on Quantification of Bacterial Phospholipid Fatty Acids.

NASA Astrophysics Data System (ADS)

Ford, S. E.; McKelvie, J. R. M.; Sherwood Lollar, B.; Slater, G. F.

2017-12-01

Understanding the distribution, abundances and metabolic activities of microbial life in the subsurface is fundamental to our understanding of biogeochemical cycling on Earth. Given that the most likely environments for life to still exist, or be preserved, on other planets and moons in the solar system are in the subsurface, a better understanding of subsurface life on Earth is also a key factor in our ability to search for life beyond the Earth. While we have made progress in investigating life in the continental subsurface in recent years, significant challenges remain. In particular, the low biomass abundance, heterogeneous distribution of biomass, and the potential for matrix effects during sampling and analysis mean that further development and optimization of methods to study subsurface life are needed. Phospholipid fatty acids (PLFA) are a useful biosignature of extant, viable microbial communities that are applied in a wide range of environments. Here we test the sensitivity of two methods of PLFA analysis (modified Bligh and Dyer, Microwave Assisted Extraction) to detect known numbers of cells doped into two distinct matrices (bentonite, crushed granite). Samples were prepared by adding known cellular concentrations of Basciullus subtilis subtilis (ATCC 6051) to crushed bentonite, or to granite, respectively, to create dilution series. Samples were extracted for PLFA using a dichloromethane-methanol modified Bligh & Dyer (mBD) or Microwave Assisted Extraction (MAE) and then quantified using GC - MS and GC - FID. Pure culture extractions yielded a linearly decreasing trend to the level of the process blank. The ratio of cells to PLFA for this trend was 2.4x104 +/- 1.9x104 cells/pmol at the lower end of the generic range of 2 to 6 x105 cells/pmol. For bentonite the PLFA results were lower than for the pure culture. PLFA results for bentonite followed a linear trend at higher concentrations, but departed from this at low concentrations indicating the potential for interference for low biomass samples. The ratio of cells to PLFA for the bentonite was to 6.2x104 +/- 4.5x104 cells/pmol, at the upper end of generic range. Ongoing comparison of the efficiency of microwave extraction and the effect of different matrices (e.g. granite) aims to optimize detection of PLFA for low biomass samples relevant to subsurface systems.

Dynamics of a pasture soil microbial community after deposition of cattle urine amended with [13C]urea.

PubMed

Petersen, Søren O; Roslev, Peter; Bol, Roland

2004-11-01

Within grazed pastures, urine patches are hot spots of nitrogen turnover, since dietary N surpluses are excreted mainly as urea in the urine. This short-term experiment investigated 13C uptake in microbial lipids after simulated deposition of cattle urine at 10.0 and 17.1 g of urea C m(-2). Confined field plots without or with cattle urine amendment were sampled after 4 and 14 days, and soil from 0- to 5-cm and 10- to 20-cm depths was analyzed for content and composition of phospholipid fatty acids (PLFAs) and for the distribution of urea-derived 13C among individual PLFAs. Carbon dioxide emissions were quantified, and the contributions derived from urea were assessed. Initial changes in PLFA composition were greater at the lower level of urea, as revealed by a principal-component analysis. At the higher urea level, osmotic stress was indicated by the dynamics of cyclopropane fatty acids and branched-chain fatty acids. Incorporation of 13C from [13C]urea was low but significant, and the largest amounts of urea-derived C were found in common fatty acids (i.e., 16:0, 16:1omega7c, and 18:1omega7) that would be consistent with growth of typical NH4(+)-oxidizing (Nitrosomonas) and NO2(-)-oxidizing (Nitrobacter) bacteria. Surprisingly, a 20 per thousand depletion of 13C in the cyclopropane fatty acid cy17:0 was observed after 4 days, which was replaced by a 10 to 20 per thousand depletion of that in cy19:0 after 14 days. Possible reasons for this pattern are discussed. Autotrophic nitrifiers could not be implicated in urea hydrolysis to any large extent, but PLFA dynamics and the incorporation of urea-derived 13C in PLFAs indicated a response of nitrifiers which differed between the two urea concentrations.

Dynamics of a Pasture Soil Microbial Community after Deposition of Cattle Urine Amended with [13C]Urea

PubMed Central

Petersen, Søren O.; Roslev, Peter; Bol, Roland

2004-01-01

Within grazed pastures, urine patches are hot spots of nitrogen turnover, since dietary N surpluses are excreted mainly as urea in the urine. This short-term experiment investigated 13C uptake in microbial lipids after simulated deposition of cattle urine at 10.0 and 17.1 g of urea C m−2. Confined field plots without or with cattle urine amendment were sampled after 4 and 14 days, and soil from 0- to 5-cm and 10- to 20-cm depths was analyzed for content and composition of phospholipid fatty acids (PLFAs) and for the distribution of urea-derived 13C among individual PLFAs. Carbon dioxide emissions were quantified, and the contributions derived from urea were assessed. Initial changes in PLFA composition were greater at the lower level of urea, as revealed by a principal-component analysis. At the higher urea level, osmotic stress was indicated by the dynamics of cyclopropane fatty acids and branched-chain fatty acids. Incorporation of 13C from [13C]urea was low but significant, and the largest amounts of urea-derived C were found in common fatty acids (i.e., 16:0, 16:1ω7c, and 18:1ω7) that would be consistent with growth of typical NH4+-oxidizing (Nitrosomonas) and NO2−-oxidizing (Nitrobacter) bacteria. Surprisingly, a 20‰ depletion of 13C in the cyclopropane fatty acid cy17:0 was observed after 4 days, which was replaced by a 10 to 20‰ depletion of that in cy19:0 after 14 days. Possible reasons for this pattern are discussed. Autotrophic nitrifiers could not be implicated in urea hydrolysis to any large extent, but PLFA dynamics and the incorporation of urea-derived 13C in PLFAs indicated a response of nitrifiers which differed between the two urea concentrations. PMID:15528493

Study of the mineralization effect on the distribution of lipids in sediments from the Cretan Sea: Evidence for hydrocarbon degradation and starvation stress

NASA Astrophysics Data System (ADS)

Polymenakou, Paraskevi N.; Tselepides, Anastasios; Stephanou, Euripides G.

2005-11-01

Sedimentary diagenetic processes alter the composition and distribution of different lipid compounds. In the present study alterations mediated by microbial communities were investigated along a bathymetric gradient (100 m at 35°23'N-25°09'E, 617 m at 35°33'N-25°08'E, 1494 m at 35°44'N-25°08'E) over the continental margin of northern Crete (Greece, Eastern Mediterranean Sea). Bacterial abundances and distribution were studied using phospholipid linked fatty acids (PLFA), in the range of C 8-C 22, released from intact phospholipids. Lipid components (aliphatic hydrocarbons, free fatty acids, glycerides and glycolipids) were studied over a 2-month incubation period. Carbon mineralization rates at all stations indicated an uneven distribution of active aerobic bacteria with values decreasing towards the deeper stations. PLFA homologue profiles denoted that aerobic gram negative and sulfur oxidizing bacteria dominated microbial communities while the anaerobic, gram positive and sulfate reducing bacteria occurred only in traces. The n-alkane (NA) composition revealed a strong predominance of homologues with odd carbon numbers suggesting an important terrestrial contribution to the sediments. The estimated descriptive ratios of NA, the sum of short chain NA (C 15-C 20) and long chain NA (C 21-C 36) to 17 α( H),21 β( H)-C 30-hopane, before and after a two-month incubation period, indicated the occurrence of hydrocarbon degradation processes. Increased ratios of saturated to unsaturated fatty acids were also recorded after the incubation indicating the starvation of bacterial communities by the end of the experiments.

[Influence of Different Straws Returning with Landfill on Soil Microbial Community Structure Under Dry and Water Farming].

PubMed

Lan, Mu-ling; Gao, Ming

2015-11-01

Based on rice, wheat, corn straw and rape, broad bean green stalk as the research object, using phospholipid fatty acid (PLFA) method, combining principal component analysis method to study the soil microbial quantity, distribution of flora, community structure characteristics under dry and water farming as two different cultivated land use types. The PLFA analysis results showed that: under dry farming, total PLFA quantity ranged 8.35-25.15 nmol x g(-1), showed rape > broad bean > corn > rice > wheat, rape and broad bean significantly increased total PLFA quantity by 1.18 and 1.08 times compared to the treatment without straw; PLFA quantity of bacterial flora in treatments with straws was higher than that without straw, and fungal biomass was significantly increased, so was the species richness of microbial community. Under water faming, the treatments of different straws returning with landfill have improved the PLFA quantity of total soil microbial and flora comparing with the treatment without straw, fungi significantly increased, and species richness of microbial communities value also increased significantly. Total PLFA quantity ranged 4.04-22.19 nmol x g(-1), showed rice > corn > wheat > broad bean > rape, which in rape and broad bean treatments were lower than the treatment without straw; fungal PLFA amount in 5 kinds of straw except broad bean treatment was significantly higher than that of the treatment without straw, bacteria and total PLFA quantity in broad bean processing were significantly lower than those of other treatments, actinomycetes, G+, G- had no significant difference between all treatments; rice, wheat, corn, rape could significantly increase the soil microbial species richness index and dominance index under water faming. The results of principal component analysis showed that broad bean green stalk had the greatest impact on the microbial community structure in the dry soil, rape green stalk and wheat straw had the biggest influence on soil microbial community structure in water soil.

[Effects of Organic and Inorganic Slow-Release Compound Fertilizer on Different Soils Microbial Community Structure].

PubMed

Wang, Fei; Yuan, Ting; Gu, Shou-kuan; Wang, Zheng-yin

2015-04-01

As a new style fertilizer, slow-control release fertilizer had been an important subject in recent years, but few researches were about soil microbial community structure diversity. Phospholipid fatty acid method was used to determined the microbial community structure diversity of acid soil and slight alkaline soil applied with slow-release compound fertilizer (SRF), chemical fertilizer (CF) and common compound fertilizer (CCF) at the 10th, 30th, 60th and 90th day under the constant temperature incubation condition. Results indicated that various bacteria (i. e 13:0, i14:0,14:0, i15:0, a15:0, i16:0, 16:12OH, 16:1w5c,16:0, i17:0, a17:0, cy17:0, 17:02OH, i18:0, 18:0 and cy19:0w8c), two actinomycetes (10Me17:0 and 10Me18:0) and only one fungus (18:1 w9c) were detected in two soils after applying slow-release compound fertilizer and other fertilizers during the whole incubation period. SRF could significantly increase the fungi PLFA content by 8.3% and 6.8% at the early stage (the 10th day and 30th day) compared with CF, as well as significantly increase by 22.7% and 17.1% at the late stage (the 60th day and 90th day) compared with CCF in acid soil. SRF significantly increased bacteria, fungi and gram positive bacteria compared with CF and CCF in incubation period (except at the 30th day) in slight alkaline soil. SRF could significantly improve the ratio of normal saturated fatty acid and monounsaturated fatty acid at the 30th day and 90th days in acid soil compared with no fertilizer (CK), CF and CCF, while as to slight alkaline soil, SRF was significantly greater than that of CK, CF and CCF only at the 60th day. SRF could significantly decrease the ratio of iso PLFA and anteiso PLFA in acid soil (in 30-90 days) and slight alkaline soil (in 10-60 days). For two soils PLFA varieties, contents and ratios of microbial community, slow-release compound fertilizer increased soil microbial PLFA varieties and contents, and decreased the influence to microbial survival environment, especially for the acid soil. Through the research of slow-release compound fertilizer on soil microbial community structure diversity, it could provide a scientific basis for widely application of slow-release compound fertilizer in agricultural production.

Community structure and soil pH determine chemoautotrophic carbon dioxide fixation in drained paddy soils.

PubMed

Long, Xi-En; Yao, Huaiying; Wang, Juan; Huang, Ying; Singh, Brajesh K; Zhu, Yong-Guan

2015-06-16

Previous studies suggested that microbial photosynthesis plays a potential role in paddy fields, but little is known about chemoautotrophic carbon fixers in drained paddy soils. We conducted a microcosm study using soil samples from five paddy fields to determine the environmental factors and quantify key functional microbial taxa involved in chemoautotrophic carbon fixation. We used stable isotope probing in combination with phospholipid fatty acid (PLFA) and molecular approaches. The amount of microbial (13)CO2 fixation was determined by quantification of (13)C-enriched fatty acid methyl esters and ranged from 21.28 to 72.48 ng of (13)C (g of dry soil)(-1), and the corresponding ratio (labeled PLFA-C:total PLFA-C) ranged from 0.06 to 0.49%. The amount of incorporationof (13)CO2 into PLFAs significantly increased with soil pH except at pH 7.8. PLFA and high-throughput sequencing results indicated a dominant role of Gram-negative bacteria or proteobacteria in (13)CO2 fixation. Correlation analysis indicated a significant association between microbial community structure and carbon fixation. We provide direct evidence of chemoautotrophic C fixation in soils with statistical evidence of microbial community structure regulation of inorganic carbon fixation in the paddy soil ecosystem.

Soil microbial community response to land use change in an agricultural landscape of western Kenya.

PubMed

Bossio, D A; Girvan, M S; Verchot, L; Bullimore, J; Borelli, T; Albrecht, A; Scow, K M; Ball, A S; Pretty, J N; Osborn, A M

2005-01-01

Tropical agroecosystems are subject to degradation processes such as losses in soil carbon, nutrient depletion, and reduced water holding capacity that occur rapidly resulting in a reduction in soil fertility that can be difficult to reverse. In this research, a polyphasic methodology has been used to investigate changes in microbial community structure and function in a series of tropical soils in western Kenya. These soils have different land usage with both wooded and agricultural soils at Kakamega and Ochinga, whereas at Ochinga, Leuro, Teso, and Ugunja a replicated field experiment compared traditional continuous maize cropping against an improved N-fixing fallow system. For all sites, principal component analysis of 16S rRNA gene denaturing gradient gel electrophoresis (DGGE) profiles revealed that soil type was the key determinant of total bacterial community structure, with secondary variation found between wooded and agricultural soils. Similarly, phospholipid fatty acid (PLFA) analysis also separated wooded from agricultural soils, primarily on the basis of higher abundance of monounsaturated fatty acids, anteiso- and iso-branched fatty acids, and methyl-branched fatty acids in the wooded soils. At Kakamega and Ochinga wooded soils had between five 5 and 10-fold higher levels of soil carbon and microbial biomass carbon than agricultural soils from the same location, whereas total enzyme activities were also lower in the agricultural sites. Soils with woody vegetation had a lower percentage of phosphatase activity and higher cellulase and chitinase activities than the agricultural soils. BIOLOG analysis showed woodland soils to have the greatest substrate diversity. Throughout the study the two functional indicators (enzyme activity and BIOLOG), however, showed lower specificity with respect to soil type and land usage than did the compositional indicators (DGGE and PLFA). In the field experiment comparing two types of maize cropping, both the maize yields and total microbial biomass were found to increase with the fallow system. Moreover, 16S rRNA gene and PLFA analyses revealed shifts in the total microbial community in response to the different management regimes, indicating that deliberate management of soils can have considerable impact on microbial community structure and function in tropical soils.

RHIZOSPHERE MICROBIOLOGY OF CHLORINATED ETHENE CONTAMINATED SOILS: EFFECTS ON PHOSPHOLIPID FATTY ACID CONTENT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brigmon, R. L.; Stanhopc, A.; Franck, M. M.

2005-05-26

Microbial degradation of chlorinated ethenes (CE) in rhizosphere soils was investigated at seepline areas impacted by CE plumes. Successful bioremediation of CE in rhizosphere soils is dependent on microbial activity, soil types, plant species, and groundwater CE concentrations. Seepline soils were exposed to trichloroethylene (TCE) and perchloroethylene (PCE) in the 10-50 ppb range. Greenhouse soils were exposed to 2-10 ppm TCE. Plants at the seepline were poplar and pine while the greenhouse contained sweet gum, willow, pine, and poplar. Phospholipid fatty acid (PLFA) analyses were performed to assess the microbial activity in rhizosphere soils. Biomass content was lowest in themore » nonvegetated control soil and highest in the Sweet Gum soil. Bacterial rhizhosphere densities, as measured by PLFA, were similar in different vegetated soils while fungi biomass was highly variable. The PLFA soil profiles showed diverse microbial communities primarily composed of Gram-negative bacteria. Adaptation of the microbial community to CE was determined by the ratio of {omega}7t/{omega}7c fatty acids. Ratios (16:1{omega}7v16:1{omega}7c and 18:l{omega}7t/18:1{omega}7c) greater than 0.1 were demonstrated in soils exposed to higher CE concentrations (10-50 ppm), indicating an adaptation to CE resulting in decreased membrane permeability. Ratios of cyclopropyl fatty acids showed that the vegetated control soil sample contained the fastest microbial turnover rate and least amount of environmental stress. PLFA results provide evidence that sulfate reducing bacteria (SRB) are active in these soils. Microcosm studies with these soils showed CE dechlorinating activity was occurring. This study demonstrates microbial adaptation to environmental contamination and supports the application of natural soil rhizosphere activity as a remedial strategy.« less

Long-term variation in above and belowground plant inputs alters soil organic matter biogeochemistry at the molecular-level

NASA Astrophysics Data System (ADS)

Simpson, M. J.; Pisani, O.; Lin, L.; Lun, O.; Simpson, A.; Lajtha, K.; Nadelhoffer, K. J.

2015-12-01

The long-term fate of soil carbon reserves with global environmental change remains uncertain. Shifts in moisture, altered nutrient cycles, species composition, or rising temperatures may alter the proportions of above and belowground biomass entering soil. However, it is unclear how long-term changes in plant inputs may alter the composition of soil organic matter (SOM) and soil carbon storage. Advanced molecular techniques were used to assess SOM composition in mineral soil horizons (0-10 cm) after 20 years of Detrital Input and Removal Treatment (DIRT) at the Harvard Forest. SOM biomarkers (solvent extraction, base hydrolysis and cupric (II) oxide oxidation) and both solid-state and solution-state nuclear magnetic resonance (NMR) spectroscopy were used to identify changes in SOM composition and stage of degradation. Microbial activity and community composition were assessed using phospholipid fatty acid (PLFA) analysis. Doubling aboveground litter inputs decreased soil carbon content, increased the degradation of labile SOM and enhanced the sequestration of aliphatic compounds in soil. The exclusion of belowground inputs (No roots and No inputs) resulted in a decrease in root-derived components and enhanced the degradation of leaf-derived aliphatic structures (cutin). Cutin-derived SOM has been hypothesized to be recalcitrant but our results show that even this complex biopolymer is susceptible to degradation when inputs entering soil are altered. The PLFA data indicate that changes in soil microbial community structure favored the accelerated processing of specific SOM components with littler manipulation. These results collectively reveal that the quantity and quality of plant litter inputs alters the molecular-level composition of SOM and in some cases, enhances the degradation of recalcitrant SOM. Our study also suggests that increased litterfall is unlikely to enhance soil carbon storage over the long-term in temperate forests.

Changes in rhizosphere bacterial gene expression following glyphosate treatment.

PubMed

Newman, Molli M; Lorenz, Nicola; Hoilett, Nigel; Lee, Nathan R; Dick, Richard P; Liles, Mark R; Ramsier, Cliff; Kloepper, Joseph W

2016-05-15

In commercial agriculture, populations and interactions of rhizosphere microflora are potentially affected by the use of specific agrichemicals, possibly by affecting gene expression in these organisms. To investigate this, we examined changes in bacterial gene expression within the rhizosphere of glyphosate-tolerant corn (Zea mays) and soybean (Glycine max) in response to long-term glyphosate (PowerMAX™, Monsanto Company, MO, USA) treatment. A long-term glyphosate application study was carried out using rhizoboxes under greenhouse conditions with soil previously having no history of glyphosate exposure. Rhizosphere soil was collected from the rhizoboxes after four growing periods. Soil microbial community composition was analyzed using microbial phospholipid fatty acid (PLFA) analysis. Total RNA was extracted from rhizosphere soil, and samples were analyzed using RNA-Seq analysis. A total of 20-28 million bacterial sequences were obtained for each sample. Transcript abundance was compared between control and glyphosate-treated samples using edgeR. Overall rhizosphere bacterial metatranscriptomes were dominated by transcripts related to RNA and carbohydrate metabolism. We identified 67 differentially expressed bacterial transcripts from the rhizosphere. Transcripts downregulated following glyphosate treatment involved carbohydrate and amino acid metabolism, and upregulated transcripts involved protein metabolism and respiration. Additionally, bacterial transcripts involving nutrients, including iron, nitrogen, phosphorus, and potassium, were also affected by long-term glyphosate application. Overall, most bacterial and all fungal PLFA biomarkers decreased after glyphosate treatment compared to the control. These results demonstrate that long-term glyphosate use can affect rhizosphere bacterial activities and potentially shift bacterial community composition favoring more glyphosate-tolerant bacteria. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

The relative contribution of methanotrophs to microbial communities and carbon cycling in soil overlying a coal-bed methane seep

USGS Publications Warehouse

Mills, Christopher T.; Slater, Gregory F.; Dias, Robert F.; Carr, Stephanie A.; Reddy, Christopher M.; Schmidt, Raleigh; Mandernack, Kevin W.

2013-01-01

Seepage of coal-bed methane (CBM) through soils is a potential source of atmospheric CH4 and also a likely source of ancient (i.e. 14C-dead) carbon to soil microbial communities. Natural abundance 13C and 14C compositions of bacterial membrane phospholipid fatty acids (PLFAs) and soil gas CO2 and CH4 were used to assess the incorporation of CBM-derived carbon into methanotrophs and other members of the soil microbial community. Concentrations of type I and type II methanotroph PLFA biomarkers (16:1ω8c and 18:1ω8c, respectively) were elevated in CBM-impacted soils compared with a control site. Comparison of PLFA and 16s rDNA data suggested type I and II methanotroph populations were well estimated and overestimated by their PLFA biomarkers, respectively. The δ13C values of PLFAs common in type I and II methanotrophs were as negative as −67‰ and consistent with the assimilation of CBM. PLFAs more indicative of nonmethanotrophic bacteria had δ13C values that were intermediate indicating assimilation of both plant- and CBM-derived carbon. Δ14C values of select PLFAs (−351 to −936‰) indicated similar patterns of CBM assimilation by methanotrophs and nonmethanotrophs and were used to estimate that 35–91% of carbon assimilated by nonmethanotrophs was derived from CBM depending on time of sampling and soil depth.

Characterization of fulvic acid fractions of dissolved organic matter during ice-out in a hyper-eutrophic, coastal pond in Antarctica

NASA Astrophysics Data System (ADS)

Cawley, Kaelin M.; McKnight, Diane M.; Miller, Penney; Cory, Rose; Fimmen, Ryan L.; Guerard, Jennifer; Dieser, Markus; Jaros, Christopher; Chin, Yu-Ping; Foreman, Christine

2013-12-01

Dissolved humic material (HDOM) is ubiquitous to all natural waters and its source material influences its chemical structure, reactivity, and bioavailability. While terrestrially derived HDOM reference materials distributed by the International Humic Substances Society (IHSS) have been readily available to engineering and scientific communities, a microbially derived reference HDOM was not, despite the well-characterized differences in the chemistry and reactivity of HDOM derived from terrestrial versus microbial sources. To address this gap, we collected a microbial reference fulvic acid from Pony Lake (PLFA) for distribution through the IHSS. Pony Lake is a saline coastal pond on Ross Island, Antarctica, where the landscape is devoid of terrestrial plants. Sample collection occurred over a 17-day period in the summer season at Pony Lake. During this time, the dissolved organic carbon (DOC) concentrations increased nearly two-fold, and the fulvic acid fraction (collected using the XAD-8 method) accounted for 14.6% of the DOC. During the re-concentration and desalting procedures we isolated two other chemically distinct fulvic acid fractions: (1) PLFA-2, which was high in carbohydrates and (2) PLFA-CER, which was high in nitrogen. The chemical characteristics (elemental analysis, optical characterization with UV-vis and fluorescence spectroscopy, and 13C NMR spectroscopy) of the three fulvic acid fractions helped to explain their behavior during isolation.

Successional and seasonal variations in soil and litter microbial community structure and function during tropical postagricultural forest regeneration: a multiyear study.

PubMed

Smith, A Peyton; Marín-Spiotta, Erika; Balser, Teri

2015-09-01

Soil microorganisms regulate fundamental biochemical processes in plant litter decomposition and soil organic matter (SOM) transformations. Understanding how microbial communities respond to changes in vegetation is critical for improving predictions of how land-cover change affects belowground carbon storage and nutrient availability. We measured intra- and interannual variability in soil and forest litter microbial community composition and activity via phospholipid fatty acid analysis (PLFA) and extracellular enzyme activity across a well-replicated, long-term chronosequence of secondary forests growing on abandoned pastures in the wet subtropical forest life zone of Puerto Rico. Microbial community PLFA structure differed between young secondary forests and older secondary and primary forests, following successional shifts in tree species composition. These successional patterns held across seasons, but the microbial groups driving these patterns differed over time. Microbial community composition from the forest litter differed greatly from those in the soil, but did not show the same successional trends. Extracellular enzyme activity did not differ with forest succession, but varied by season with greater rates of potential activity in the dry seasons. We found few robust significant relationships among microbial community parameters and soil pH, moisture, carbon, and nitrogen concentrations. Observed inter- and intrannual variability in microbial community structure and activity reveal the importance of a multiple, temporal sampling strategy when investigating microbial community dynamics with land-use change. Successional control over microbial composition with forest recovery suggests strong links between above and belowground communities. © 2015 John Wiley & Sons Ltd.

Biodegradation of spilled diesel fuel in agricultural soil: effect of humates, zeolite, and bioaugmentation.

PubMed

Kuráň, Pavel; Trögl, Josef; Nováková, Jana; Pilařová, Věra; Dáňová, Petra; Pavlorková, Jana; Kozler, Josef; Novák, František; Popelka, Jan

2014-01-01

Possible enhancement of biodegradation of petroleum hydrocarbons in agricultural soil after tank truck accident (~5000 mg/kg dry soil initial concentration) by bioaugmentation of diesel degrading Pseudomonas fluorescens strain and addition of abiotic additives (humates, zeolite) was studied in a 9-month pot experiment. The biodegradation process was followed by means of analytical parameters (hydrocarbon index expressed as content of C10-C40 aliphatic hydrocarbons, ratio pristane/C17, and total organic carbon content) and characterization of soil microbial community (content of phospholipid fatty acids (PLFA) as an indicator of living microbial biomass, respiration, and dehydrogenase activity). The concentration of petroleum hydrocarbons (C10-C40) was successfully reduced by ~60% in all 15 experiment variants. The bioaugmentation resulted in faster hydrocarbon elimination. On the contrary, the addition of humates and zeolite caused only a negligible increase in the degradation rate. These factors, however, affected significantly the amount of PLFA. The humates caused significantly faster increase of the total PLFA suggesting improvement of the soil microenvironment. Zeolite caused significantly slower increase of the total PLFA; nevertheless it aided in homogenization of the soil. Comparison of microbial activities and total PLFA revealed that only a small fraction of autochthonous microbes took part in the biodegradation which confirms that bioaugmentation was the most important treatment.

Metaproteomics to investigate the impact of sampling-site biogeochemistry on structure and functionality of leaf-litter degrading microbial communities

NASA Astrophysics Data System (ADS)

Schneider, Thomas; Keiblinger, Katharina; Gerrits, Bertran; Schmid, Emanuel; Eberl, Leo; Zechmeister-Boltenstern, Sophie; Riedel, Kathrin

2010-05-01

The composition of organic matter in natural ecosystems is strongly influenced by the microorganisms present. Conversely, bacteria and fungi are limited by the amount and type of organic matter available in a given environment, most of which is ultimately derived from plants. Changes in the stoichiometry and biochemical constituents of plant litter may therefore alter species composition and elicit changes in the activities of microbial communities and their component parts. The identification of the microbial proteins of a given habitat together with the analysis of their phylogenetic origin and their spatial and temporal distribution are expected to provide fundamentally new insights into the role of microbial diversity in biogeochemical processes. To relate structure and functionality of microbial communities involved in leaf-litter decomposition we determined biogeochemistry, community structure by phospholipid fatty acid (PLFA)-analyses, enzymatic activities, and analysed the protein complement of different litter types, which were collected in winter and spring at various Austrian sampling sites, in a semi-quantitative proteomics approach by one dimensional polyacrylamide gel electrophoresis (1-D-SDS-PAGE) combined with liquid chromatography/tandem mass-spectrometry (LC-MS/MS). Protein abundances were determined by counting the number of MS/MS spectra assigned to each protein. In samples with high manganese and phosphor content a significant increase of fungal proteins from February to May was observed, which was in good agreement with the PLFA-analyses showing similar trends towards an increase of the fungal community. In contrast, the PLFA analysis revealed no temporal changes in the community at Achenkirch and even a decrease in the fungal/bacterial ratio at Klausen-Leopoldsdorf, two sampling sites low in P and Mn; similar trends are reflected in our spectral counts. In conclusion, semi-quantitative proteome- and PLFA-analyses suggest that fungal and bacterial abundance positively correlates with the total amount of P and Mn within the different litter types. Spectral counts of extracellular enzymes demonstrated a significant increase of these enzymes in the May, which was also mirrored by measurements of total enzymatic activities. The finding that almost all hydrolytic enzymes identified from litter were of fungal origin suggests a prominent role of fungi during aerobic litter decomposition.

Phospholipid Fatty Acids as Physiological Indicators of Paracoccus denitrificans Encapsulated in Silica Sol-Gel Hydrogels

PubMed Central

Trögl, Josef; Jirková, Ivana; Kuráň, Pavel; Akhmetshina, Elmira; Brovdyová, Tat′jána; Sirotkin, Alexander; Kirilina, Tatiana

2015-01-01

The phospholipid fatty acid (PLFA) content was determined in samples of Paracoccus denitrificans encapsulated in silica hydrogel films prepared from prepolymerized tetramethoxysilane (TMOS). Immediately after encapsulation the total PLFA concentration was linearly proportional to the optical density (600 nm) of the input microbial suspension (R2 = 0.99). After 7 days this relationship remained linear, but with significantly decreased slope, indicating a higher extinction of bacteria in suspensions of input concentration 108 cells/mL and higher. trans-Fatty acids, indicators of cytoplasmatic membrane disturbances, were below the detection limit. The cy/pre ratio (i.e., ratio of cyclopropylated fatty acids (cy17:0 + cy19:0) to their metabolic precursors (16:1ω7 + 18:1ω7)), an indicator of the transition of the culture to a stationary growth-phase, decreased depending on co-immobilization of nutrients in the order phosphate buffer > mineral medium > Luria Broth rich medium. The ratio, too, was logarithmically proportional to cell concentration. These results confirm the applicability of total PLFA as an indicator for the determination of living biomass and cy/pre ratio for determination of nutrient limitation of microorganisms encapsulated in sol-gel matrices. This may be of interest for monitoring of sol-gel encapsulated bacteria proposed as optical recognition elements in biosensor construction, as well as other biotechnological applications. PMID:25690547

Soil warming alters microbial substrate use in alpine soils.

PubMed

Streit, Kathrin; Hagedorn, Frank; Hiltbrunner, David; Portmann, Magdalena; Saurer, Matthias; Buchmann, Nina; Wild, Birgit; Richter, Andreas; Wipf, Sonja; Siegwolf, Rolf T W

2014-04-01

Will warming lead to an increased use of older soil organic carbon (SOC) by microbial communities, thereby inducing C losses from C-rich alpine soils? We studied soil microbial community composition, activity, and substrate use after 3 and 4 years of soil warming (+4 °C, 2007-2010) at the alpine treeline in Switzerland. The warming experiment was nested in a free air CO2 enrichment experiment using depleted (13)CO2 (δ(13)C = -30‰, 2001-2009). We traced this depleted (13)C label in phospholipid fatty acids (PLFA) of the organic layer (0-5 cm soil depth) and in C mineralized from root-free soils to distinguish substrate ages used by soil microorganisms: fixed before 2001 ('old'), from 2001 to 2009 ('new') or in 2010 ('recent'). Warming induced a sustained stimulation of soil respiration (+38%) without decline in mineralizable SOC. PLFA concentrations did not reveal changes in microbial community composition due to soil warming, but soil microbial metabolic activity was stimulated (+66%). Warming decreased the amount of new and recent C in the fungal biomarker 18:2ω6,9 and the amount of new C mineralized from root-free soils, implying a shift in microbial substrate use toward a greater use of old SOC. This shift in substrate use could indicate an imbalance between C inputs and outputs, which could eventually decrease SOC storage in this alpine ecosystem. © 2013 John Wiley & Sons Ltd.

Molecular characterization of phytoplankton dissolved organic matter (DOM) and sulfur components using high resolution Orbitrap mass spectrometry.

PubMed

Mangal, Vaughn; Stock, Naomi L; Guéguen, Celine

2016-03-01

Orbitrap high resolution mass spectrometry (HRMS) with electrospray ionization in both positive and negative polarity was conducted on Suwannee River fulvic acid (SRFA), Pony Lake fulvic acid (PLFA) standards, and dissolved organic matter (DOM) released by freshwater phytoplankton (Scenedesmus obliquus, Euglena mutabilis, and Euglena gracilis). Three-dimensional van Krevelen diagrams expressing various oxygenation states of sulfur molecules and abundance plots of sulfur-containing species were constructed. Orbitrap HRMS analysis of SRFA found a high density of peaks in the lignin region (77 %) and low density of protein material (6.53 %), whereas for PLFA, 25 % of the total peaks were lignin related compared to 56 % of peaks in protein regions, comparable with other HRMS studies. Phytoplankton-derived DOM of S. obliquus, E. mutabilis, and E. gracilis was dominated by protein molecules at respective percentages of 36, 46, and 49 %, and is consistent with previous experiments examining phytoplankton-derived DOM composition. The normalized percentage of SO-containing compounds was determined among the three phytoplankton to be 56 % for Scenedesmus, 54 % for E. mutabilis, and 47 % for E. gracilis, suggesting variation between sulfur content in phytoplankton-derived DOM and differences in metal binding capacities. These results suggest the level of resolution by Orbitrap mass spectrometry is sufficient for preliminary characterization of phytoplankton DOM at an affordable cost relative to other HRMS techniques.

Effects of ammonium-based ionic liquids and 2,4-dichlorophenol on the phospholipid fatty acid composition of zebrafish embryos.

PubMed

Piotrowska, Aleksandra; Syguda, Anna; Wyrwas, Bogdan; Chrzanowski, Lukasz; Luckenbach, Till; Heipieper, Hermann J

2018-01-01

Ionic liquids consisting of a combination of herbicidal anions with a quaternary ammonium cation act as efficient herbicides, which are under consideration to be used in the agriculture. In the present study, we used embryos of the zebrafish (Danio rerio) as a model to assess the toxic potential of ammonium-based ionic liquids for aquatic organisms. As we assumed interference of the partially hydrophobic ionic liquid cation with lipids, we investigated the adaptation response in the lipid composition of the zebrafish embryos, triggered by the ionic compound. Therefore, the impact of ammonium-based ionic liquids with different lengths of the alkyl chain ([C6,C6,C1,C1N][Br], [C8,C8,C1,C1N][Br]) on the phospholipid fatty acid (PLFA) profile of zebrafish embryos up to 72 hours post fertilization (hpf) was examined. Furthermore, the changes in the unsaturation index (UI) of PLFAs, as the sum parameter of membrane fluidity in eukaryotic cells, were presented. The PLFA's UI in the zebrafish embryos upon exposure to quaternary ammonium salts was compared to the UI of the embryos upon exposure to nonionic 2,4-dichlorophenol, which has a similar hydrophobicity but is structurally different to [C8,C8,C1,C1N][Br]. It was shown that for ammonium-based ionic liquid precursors non-specific mode of action occurs and the toxic effect on lipid composition of zebrafish embryos can be well predicted based on chemical properties, like hydrophobicity. Furthermore, the changes in PLFAs, expressed by the UI, can be useful to study toxic effects of organic contamination. However, for zebrafish embryos, after ionic liquids and 2,4-DCP exposure, the changes were observed at high lethal concentrations, which caused the incidence of lethality of 30 and 50% of a group of test animals.

Biodegradation of Spilled Diesel Fuel in Agricultural Soil: Effect of Humates, Zeolite, and Bioaugmentation

PubMed Central

Kuráň, Pavel; Nováková, Jana; Pilařová, Věra; Dáňová, Petra; Pavlorková, Jana; Kozler, Josef; Novák, František

2014-01-01

Possible enhancement of biodegradation of petroleum hydrocarbons in agricultural soil after tank truck accident (~5000 mg/kg dry soil initial concentration) by bioaugmentation of diesel degrading Pseudomonas fluorescens strain and addition of abiotic additives (humates, zeolite) was studied in a 9-month pot experiment. The biodegradation process was followed by means of analytical parameters (hydrocarbon index expressed as content of C10–C40 aliphatic hydrocarbons, ratio pristane/C17, and total organic carbon content) and characterization of soil microbial community (content of phospholipid fatty acids (PLFA) as an indicator of living microbial biomass, respiration, and dehydrogenase activity). The concentration of petroleum hydrocarbons (C10–C40) was successfully reduced by ~60% in all 15 experiment variants. The bioaugmentation resulted in faster hydrocarbon elimination. On the contrary, the addition of humates and zeolite caused only a negligible increase in the degradation rate. These factors, however, affected significantly the amount of PLFA. The humates caused significantly faster increase of the total PLFA suggesting improvement of the soil microenvironment. Zeolite caused significantly slower increase of the total PLFA; nevertheless it aided in homogenization of the soil. Comparison of microbial activities and total PLFA revealed that only a small fraction of autochthonous microbes took part in the biodegradation which confirms that bioaugmentation was the most important treatment. PMID:24672346

Response of microbial community composition and function to soil climate change

USGS Publications Warehouse

Waldrop, M.P.; Firestone, M.K.

2006-01-01

Soil microbial communities mediate critical ecosystem carbon and nutrient cycles. How microbial communities will respond to changes in vegetation and climate, however, are not well understood. We reciprocally transplanted soil cores from under oak canopies and adjacent open grasslands in a California oak-grassland ecosystem to determine how microbial communities respond to changes in the soil environment and the potential consequences for the cycling of carbon. Every 3 months for up to 2 years, we monitored microbial community composition using phospholipid fatty acid analysis (PLFA), microbial biomass, respiration rates, microbial enzyme activities, and the activity of microbial groups by quantifying 13C uptake from a universal substrate (pyruvate) into PLFA biomarkers. Soil in the open grassland experienced higher maximum temperatures and lower soil water content than soil under the oak canopies. Soil microbial communities in soil under oak canopies were more sensitive to environmental change than those in adjacent soil from the open grassland. Oak canopy soil communities changed rapidly when cores were transplanted into the open grassland soil environment, but grassland soil communities did not change when transplanted into the oak canopy environment. Similarly, microbial biomass, enzyme activities, and microbial respiration decreased when microbial communities were transplanted from the oak canopy soils to the grassland environment, but not when the grassland communities were transplanted to the oak canopy environment. These data support the hypothesis that microbial community composition and function is altered when microbes are exposed to new extremes in environmental conditions; that is, environmental conditions outside of their "life history" envelopes. ?? 2006 Springer Science+Business Media, Inc.

Response of the soil microbial community to imazethapyr application in a soybean field.

PubMed

Xu, Jun; Guo, Liqun; Dong, Fengshou; Liu, Xingang; Wu, Xiaohu; Sheng, Yu; Zhang, Ying; Zheng, Yongquan

2013-01-01

The objective of this study was to determine the effects of imazethapyr on soil microbial communities combined with its effect on soybean growth. A short-term field experiment was conducted, and imazethapyr was applied to the soil at three different doses [1-fold, 10-fold, and 50-fold of the recommended field rate (H1, H10, H50)] during the soybean seedling period (with two leaves). Soil sampling was performed after 1, 7, 30, 60, 90, and 120 days of application to determine the imazethapyr concentration and microbial community structure by investigating phospholipid fatty acids (PLFA) and microbial biomass carbon (MBC). The half-lives of the imazethapyr in the field soil varied from 30.1 to 43.3 days. Imazethapyr at H1 was innocuous to soybean plants, but imazethapyr at H10 and H50 led to a significant inhibition in soybean plant height and leaf number. The soil MBC, total PLFA, and bacterial PLFA were decreased by the application of imazethapyr during the initial period and could recover by the end of the experiment. The ratio of Gram-negative/Gram-positive (GN/GP) bacteria during the three treatments went through increases and decreases, and then recovered at the end of the experiment. The fungal PLFA of all three treatments increased during the initial period and then declined, and only the fungal PLFA at H50 recovered by the end of the treatment. A principal component analysis (PCA) of the PLFA clearly separated the treatments and sampling times, and the results demonstrate that imazethapyr alters the microbial community structure. This is the first systemic study reporting the effects of imazethapyr on the soil microbial community structure under soybean field conditions.

A soil alteration index based on phospholipid fatty acids.

PubMed

Puglisi, Edoardo; Nicelli, Marco; Capri, Ettore; Trevisan, Marco; Del Re, Attilio A M

2005-12-01

Phospholipid fatty acid (PLFA) analysis has gained great importance in the study of soil microbial community structure. This structure can give indication of the soil status. Purpose of the present paper is to analyse PLFA patterns in altered agricultural soils in order to develop a soil status alteration index. Soils subjected either to intensive agricultural exploitation, or to overflow by municipal and industrial wastes, or to irrigation with saline waters were analysed for PLFA content and compared to adjacent untreated soils by means of different statistical techniques. Principal component analysis separated PLFAs in three groups: unsaturated PLFAs (first axis, 48% of total variance), monounsaturated and cyclopropane PLFAs (second axis, 28% of total variance) and polyunsaturated PLFAs (third axis, 24% of total variance). By means of canonical discriminant analysis, a soil alteration index (SAI) was produced from 15 PLFAs using two data sets. A third data set was used to test the SAI general validity together with other data sets reported in literature. The index validity was confirmed in most cases: SAI gave higher scores for control soils and was generally able to classify soils according to their reported degree of alteration.

The role of dissolved organic matter (DOM) quality in the growth enhancement of Alexandrium fundyense (Dinophyceae) in laboratory culture(1).

PubMed

Cawley, Kaelin M; Koerfer, Verena; McKnight, Diane M

2013-06-01

Several algal species responsible for harmful algal blooms (HABs), such as Alexandrium fundyense, are mixotrophic under certain environmental conditions. The ability to switch between photosynthetic and heterotrophic modes of growth may play a role in the development of HABs in coastal regions. We examined the influence of humic dissolved organic matter (HDOM) derived from terrestrial (plant/soil) and microbial sources on the growth of A. fundyense. We found that a terrestrially derived HDOM, Suwannee River humic acid (SRHA), did enhance A. fundyense growth; however, a microbially derived HDOM, Pony Lake fulvic acid (PLFA) did not enhance growth. A. fundyense grows in association with bacteria in culture and we observed that bacterial cell densities were much lower in A. fundyense cultures than in bacteria-only cultures, consistent with bacterial grazing by A. fundyense in culture. In bacteria-only cultures with added algal exudates (EX), the addition of PLFA and SRHA resulted in a slight increase in bacterial cell density compared to cultures without HDOM added. Changes over time in the chemical quality of the HDOM in the A. fundyense cultures reflected contributions of microbially derived material with similar characteristics as the PLFA. Overall, these results suggest that the chemical differences between SRHA and PLFA are responsible for the greater effect of SRHA on A. fundyense growth, and that the differential effect is not a result of an effect on the growth of associated bacteria. © 2013 Phycological Society of America.

A comparison of sole carbon source utilization patterns and phospholipid fatty acid profiles to detect changes in the root microflora of hydroponically grown crops.

PubMed

Khalil, S; Bååth, E; Alsanius, B; Englund, J E; Sundin, P; Gertsson, U E; Jensén, P

2001-04-01

Sole carbon source utilization (SCSU) patterns and phospholipid fatty acid (PLFA) profiles were compared with respect to their potential to characterize root-inhabiting microbial communities of hydroponically grown crops. Sweet pepper (Capsicum annum cv. Evident), lettuce (Lactuca sativa cv. Grand Rapids), and four different cultivars of tomato (Lycopersicon esculentum cvs. Gitana, Armada, Aromata, and Elin) were grown in 1-L black plastic beakers placed in a cultivation chamber with artificial light. In addition to the harvest of the plants after 6 weeks, plants of one tomato cultivar, cv. Gitana, were also harvested after 4 and 8 weeks. The cultivation in this study was performed twice. Principal component analysis was used to analyze the data. Both characterization methods had the ability to discriminate between the root microflora of different plant species, cultivars, and one tomato cultivar at different ages. Differences in both SCSU patterns and PLFA profiles were larger between plant species than between cultivars, but for both methods the largest differences were between the two cultivations. Still, the differences between treatments were always due to differences in the same PLFAs in both cultivations. This was not the case for the SCSU patterns when different plant ages were studied. Furthermore, PLFA profiles showed less variation between replicates than did SCSU patterns. This larger variation observed among the SCSU data indicates that PLFA may be more useful to detect changes in the root microflora of hydroponically grown crops than the SCSU technique.

Phosphorus status and microbial community of paddy soil with the growth of annual ryegrass (Lolium multiflorum Lam.) under different phosphorus fertilizer treatments*

PubMed Central

Guo, Hai-chao; Wang, Guang-huo

2009-01-01

Annual ryegrass (Lolium multiflorum Lam.) was grown in paddy soil in pots under different phosphorus (P) fertilizer treatments to investigate changes of P fractions and microbial community of the soil. The treatments included Kunyang phosphate rock (KPR) applications at 50 mg P/kg (KPR50) and 250 mg P/kg (KPR250), mono-calcium phosphate (MCP) application at 50 mg P/kg (MCP50), and the control without P application. The results showed that KPR50, KPR250, and MCP50 applications significantly increased the dry weight of the ryegrass by 13%, 38%, and 55%, and increased P uptake by 19%, 135%, and 324%, respectively. Compared with MCP50, the relative effectiveness of KPR50 and KPR250 treatments in ryegrass production was about 23% and 68%, respectively. After one season of ryegrass growth, the KPR50, KPR250, and MCP50 applications increased soil-available P by 13.4%, 26.8%, and 55.2%, respectively. More than 80% of the applied KPR-P remained as HCl-P fraction in the soil. Phospholipid fatty acid (PLFA) analysis showed that the total and bacterial PLFAs were significantly higher in the soils with KPR250 and MCP50 treatments compared with KPR50 and control. The latter had no significant difference in the total or bacterial PLFAs. The KPR50, KPR250, and MCP50 treatments increased fungal PLFA by 69%, 103%, and 69%, respectively. Both the principal component analysis and the cluster analysis of the PLFA data suggest that P treatments altered the microbial community composition of the soils, and that P availability might be an important contributor to the changes in the microbial community structure during the ryegrass growth in the paddy soils. PMID:19817001

Do temperate tree species diversity and identity influence soil microbial community function and composition?

PubMed

Khlifa, Rim; Paquette, Alain; Messier, Christian; Reich, Peter B; Munson, Alison D

2017-10-01

Studies of biodiversity-ecosystem function in treed ecosystems have generally focused on aboveground functions. This study investigates intertrophic links between tree diversity and soil microbial community function and composition. We examined how microbial communities in surface mineral soil responded to experimental gradients of tree species richness (SR), functional diversity (FD), community-weighted mean trait value (CWM), and tree identity. The site was a 4-year-old common garden experiment near Montreal, Canada, consisting of deciduous and evergreen tree species mixtures. Microbial community composition, community-level physiological profiles, and respiration were evaluated using phospholipid fatty acid (PLFA) analysis and the MicroResp ™ system, respectively. The relationship between tree species richness and glucose-induced respiration (GIR), basal respiration (BR), metabolic quotient (qCO 2 ) followed a positive but saturating shape. Microbial communities associated with species mixtures were more active (basal respiration [BR]), with higher biomass (glucose-induced respiration [GIR]), and used a greater number of carbon sources than monocultures. Communities associated with deciduous tree species used a greater number of carbon sources than those associated with evergreen species, suggesting a greater soil carbon storage capacity. There were no differences in microbial composition (PLFA) between monocultures and SR mixtures. The FD and the CWM of several functional traits affected both BR and GIR. In general, the CWM of traits had stronger effects than did FD, suggesting that certain traits of dominant species have more effect on ecosystem processes than does FD. Both the functions of GIR and BR were positively related to aboveground tree community productivity. Both tree diversity (SR) and identity (species and functional identity-leaf habit) affected soil microbial community respiration, biomass, and composition. For the first time, we identified functional traits related to life-history strategy, as well as root traits that influence another trophic level, soil microbial community function, via effects on BR and GIR.

Incorporation of dietary n-3 fatty acids into selective phosphatidylcholine lipids in human plasma after salmon intake

USDA-ARS?s Scientific Manuscript database

Elevated intake of n-3 long chain polyunsaturated fatty acids (n-3 LCPUFA) is associated with reduced risk for cardiovascular disease. Intake of n-3 LCPUFA is often quantified by analysis of plasma phospholipid fatty acids (PLFA); however, the typical analysis by gas chromatography does not allow fo...

A comparison of stable-isotope probing of DNA and phospholipid fatty acids to study prokaryotic functional diversity in sulfate-reducing marine sediment enrichment slurries.

PubMed

Webster, Gordon; Watt, Lynsey C; Rinna, Joachim; Fry, John C; Evershed, Richard P; Parkes, R John; Weightman, Andrew J

2006-09-01

Marine sediment slurries enriched for anaerobic, sulfate-reducing prokaryotic communities utilizing glucose and acetate were used to provide the first comparison between stable-isotope probing (SIP) of phospholipid fatty acids (PLFA) and DNA (16S rRNA and dsrA genes) biomarkers. Different 13C-labelled substrates (glucose, acetate and pyruvate) at low concentrations (100 microM) were used over a 7-day incubation to follow and identify carbon flow into different members of the community. Limited changes in total PLFA and bacterial 16S rRNA gene DGGE profiles over 7 days suggested the presence of a stable bacterial community. A broad range of PLFA were rapidly labelled (within 12 h) in the 13C-glucose slurry but this changed with time, suggesting the presence of an active glucose-utilizing population and later development of another population able to utilize glucose metabolites. The identity of the major glucose-utilizers was unclear as 13C-enriched PLFA were common (16:0, 16:1, 18:1omega7, highest incorporation) and there was little difference between 12C- and 13C-DNA 16S rRNA gene denaturing gradient gel electrophoresis (DGGE) profiles. Seemingly glucose, a readily utilizable substrate, resulted in widespread incorporation consistent with the higher extent of 13C-incorporation (approximately 10 times) into PLFA compared with 13C-acetate or 13C-pyruvate. 13C-PLFA in the 13C-acetate and 13C-pyruvate slurries were similar to each other and to those that developed in the 13C-glucose slurry after 4 days. These were more diagnostic, with branched odd-chain fatty acids (i15:0, a15:0 and 15:1omega6) possibly indicating the presence of Desulfococcus or Desulfosarcina sulfate-reducing bacteria (SRB) and sequences related to these SRB were in the 13C-acetate-DNA dsrA gene library. The 13C-acetate-DNA 16S rRNA gene library also contained sequences closely related to SRB, but these were the acetate-utilizing Desulfobacter sp., as well as a broad range of uncultured Bacteria. In contrast, analysis of DGGE bands from 13C-DNA demonstrated that the candidate division JS1 and Firmicutes were actively assimilating 13C-acetate. Denaturing gradient gel electrophoresis also confirmed the presence of JS1 in the 13C-DNA from the 13C-glucose slurry. These results demonstrate that JS1, originally found in deep subsurface sediments, is more widely distributed in marine sediments and provides the first indication of its metabolism; incorporation of acetate and glucose (or glucose metabolites) under anaerobic, sulfate-reducing conditions. Here we demonstrate that PLFA- and DNA-SIP can be used together in a sedimentary system, with low concentrations of 13C-substrate and overlapping incubation times (up to 7 days) to provide complementary, although not identical, information on carbon flow and the identity of active members of an anaerobic prokaryotic community.

Succession of Phenotypic, Genotypic, and Metabolic Community Characteristics during In Vitro Bioslurry Treatment of Polycyclic Aromatic Hydrocarbon-Contaminated Sediments

PubMed Central

Ringelberg, David B.; Talley, Jeffrey W.; Perkins, Edward J.; Tucker, Samuel G.; Luthy, Richard G.; Bouwer, Edward J.; Fredrickson, Herbert L.

2001-01-01

Dredged harbor sediment contaminated with polycyclic aromatic hydrocarbons (PAHs) was removed from the Milwaukee Confined Disposal Facility and examined for in situ biodegradative capacity. Molecular techniques were used to determine the successional characteristics of the indigenous microbiota during a 4-month bioslurry evaluation. Ester-linked phospholipid fatty acids (PLFA), multiplex PCR of targeted genes, and radiorespirometry techniques were used to define in situ microbial phenotypic, genotypic, and metabolic responses, respectively. Soxhlet extractions revealed a loss in total PAH concentrations of 52%. Individual PAHs showed reductions as great as 75% (i.e., acenapthene and fluorene). Rates of 14C-PAH mineralization (percent/day) were greatest for phenanthrene, followed by pyrene and then chrysene. There was no mineralization capacity for benzo[a]pyrene. Ester-linked phospholipid fatty acid analysis revealed a threefold increase in total microbial biomass and a dynamic microbial community composition that showed a strong correlation with observed changes in the PAH chemistry (canonical r2 of 0.999). Nucleic acid analyses showed copies of genes encoding PAH-degrading enzymes (extradiol dioxygenases, hydroxylases, and meta-cleavage enzymes) to increase by as much as 4 orders of magnitude. Shifts in gene copy numbers showed strong correlations with shifts in specific subsets of the extant microbial community. Specifically, declines in the concentrations of three-ring PAH moieties (i.e., phenanthrene) correlated with PLFA indicative of certain gram-negative bacteria (i.e., Rhodococcus spp. and/or actinomycetes) and genes encoding for naphthalene-, biphenyl-, and catechol-2,3-dioxygenase degradative enzymes. The results of this study suggest that the intrinsic biodegradative potential of an environmental site can be derived from the polyphasic characterization of the in situ microbial community. PMID:11282603

Soil water availability and microsite mediate fungal and bacterial phospholipid fatty acid biomarker abundances in Mojave Desert soils exposed to elevated atmospheric CO2

NASA Astrophysics Data System (ADS)

Jin, V. L.; Schaeffer, S. M.; Ziegler, S. E.; Evans, R. D.

2011-06-01

Changes in the rates of nitrogen (N) cycling, microbial carbon (C) substrate use, and extracellular enzyme activities in a Mojave Desert ecosystem exposed to elevated atmospheric CO2 suggest shifts in the size and/or functional characteristics of microbial assemblages in two dominant soil microsites: plant interspaces and under the dominant shrub Larrea tridentata. We used ester-linked phospholipid fatty acid (PLFA) biomarkers as a proxy for microbial biomass to quantify spatial and temporal differences in soil microbial communities from February 2003 to May 2005. Further, we used the 13C signature of the fossil CO2 source for elevated CO2 plots to trace recent plant C inputs into soil organic matter (SOM) and broad microbial groups using δ13C (‰). Differences between individual δ13CPLFA and δ13CSOM for fungal biomarkers indicated active metabolism of newer C in elevated CO2 soils. Total PLFA-C was greater in shrub microsites compared to plant interspaces, and CO2 treatment differences within microsites increased under higher soil water availability. Total, fungal, and bacterial PLFA-C increased with decreasing soil volumetric water content (VWC) in both microsites, suggesting general adaptations to xeric desert conditions. Increases in fungal-to-bacterial PLFA-C ratio with decreasing VWC reflected functional group-specific responses to changing soil water availability. While temporal and spatial extremes in resource availability in desert ecosystems contribute to the difficulty in identifying common trends or mechanisms driving microbial responses in less extreme environments, we found that soil water availability and soil microsite interacted with elevated CO2 to shift fungal and bacterial biomarker abundances in Mojave Desert soils.

Quantitative determination of microbial activity and community nutritional status in estuarine sediments: evidence for a disturbance artifact

NASA Technical Reports Server (NTRS)

Findlay, R. H.; Pollard, P. C.; Moriarty, D. J.; White, D. C.

1985-01-01

In estuarine sediments with a high degree of vertical heterogeneity in reduced substrate and terminal electron acceptor concentrations, the method of exposure of the microbiota to labeled substrates can introduce a "disturbance artifact" into measures of metabolic activity. The detection of this artifact is based on quantitative measurement of the relative rates of incorporation of [14C]acetate into phospholipid fatty acids (PLFA) and endogenous storage lipid, poly-beta-hydroxyalkanoate (PHA). Previous studies have shown that PLFA synthesis measures cellular growth and that PHA synthesis measures carbon accumulation (unbalanced growth). The "disturbance artifact" of exposure to [14C]acetate was demonstrated by comparing injection of a core with the usual or pore-water replacement or slurry techniques. Only injection of labeled substrate allowed detection of preassay disturbance of the sediment with a garden rake. The raking increased PLFA synthesis with little effect to differences in concentration or distribution of [14C]acetate in the 10-min incubation. Bioturbation induced by sand dollar feeding in estuarine sediment could be detected in an increased PLFA/PHA ratio which was due to decreased PHA synthesis if the addition of labeled substrate was by the injection technique. Addition of labeled precursors to sediment by slurry or pore-water replacement induces greater disturbance artifacts than injection techniques.

Rhizospheric effects on the microbial community of e-waste-contaminated soils using phospholipid fatty acid and isoprenoid glycerol dialkyl glycerol tetraether analyses.

PubMed

Song, Mengke; Cheng, Zhineng; Luo, Chunling; Jiang, Longfei; Zhang, Dayi; Yin, Hua; Zhang, Gan

2018-04-01

We performed the study of rhizospheric effects on soil microbial community structure, including bacteria, fungi, actinomycete, and archaea, at an electronic waste (e-waste) recycling site by analyzing the phospholipid fatty acid (PLFA) and isoprenoid glycerol dialkyl glycerol tetraether (GDGT) contents. By comparing PLFA and isoprenoid GDGT profiles of rhizospheric and surrounding bulk soils of 11 crop species, we observed distinct microbial community structures. The total PLFA concentration was significantly higher in rhizospheric soils than in non-rhizospheric soils, whereas no obvious difference was found in the total isoprenoid GDGT concentrations. The microbial community structure was also different, with higher ratios of fungal-to-bacterial PLFAs (F/B) and lower relative abundance of Gram-positive bacteria in rhizospheric soils. The extent of rhizospheric effects varied among plant species, and Colocasia esculenta L. had the greatest positive effects on the total microbial biomass. Dissolved organic carbon and pH were the main environmental factors affecting the microbial community represented by PLFAs, while the archaeal community was influenced by copper and zinc in all soils. These results offer a comprehensive view of rhizospheric effects on microbes in heavy metal and persistent organic pollutant co-contaminated soil, and provide fundamental knowledge regarding microbial ecology in e-waste-contaminated soils.

Changes in relative and absolute concentrations of plasma phospholipid fatty acids observed in a randomized trial of Omega-3 fatty acids supplementation in Uganda.

PubMed

Song, Xiaoling; Diep, Pho; Schenk, Jeannette M; Casper, Corey; Orem, Jackson; Makhoul, Zeina; Lampe, Johanna W; Neuhouser, Marian L

2016-11-01

Expressing circulating phospholipid fatty acids (PLFAs) in relative concentrations has some limitations: the total of all fatty acids are summed to 100%; therefore, the values of individual fatty acid are not independent. In this study we examined if both relative and absolute metrics could effectively measure changes in circulating PLFA concentrations in an intervention trial. 66 HIV and HHV8 infected patients in Uganda were randomized to take 3g/d of either long-chain omega-3 fatty acids (1856mg EPA and 1232mg DHA) or high-oleic safflower oil in a 12-week double-blind trial. Plasma samples were collected at baseline and end of trial. Relative weight percentage and absolute concentrations of 41 plasma PLFAs were measured using gas chromatography. Total cholesterol was also measured. Intervention-effect changes in concentrations were calculated as differences between end of 12-week trial and baseline. Pearson correlations of relative and absolute concentration changes in individual PLFAs were high (>0.6) for 37 of the 41 PLFAs analyzed. In the intervention arm, 17 PLFAs changed significantly in relative concentration and 16 in absolute concentration, 15 of which were identical. Absolute concentration of total PLFAs decreased 95.1mg/L (95% CI: 26.0, 164.2; P=0.0085), but total cholesterol did not change significantly in the intervention arm. No significant change was observed in any of the measurements in the placebo arm. Both relative weight percentage and absolute concentrations could effectively measure changes in plasma PLFA concentrations. EPA and DHA supplementation changes the concentrations of multiple plasma PLFAs besides EPA and DHA.Both relative weight percentage and absolute concentrations could effectively measure changes in plasma phospholipid fatty acid (PLFA) concentrations. Copyright © 2016 Elsevier Ltd. All rights reserved.

Characterization of soil bacterial, archaeal and fungal communities inhabiting archaeological human-impacted layers at Monte Iato settlement (Sicily, Italy).

PubMed

Siles, José A; Öhlinger, Birgit; Cajthaml, Tomas; Kistler, Erich; Margesin, Rosa

2018-01-30

Microbial communities in human-impacted soils of ancient settlements have been proposed to be used as ecofacts (bioindicators) of different ancient anthropogenic activities. In this study, bacterial, archaeal and fungal communities inhabiting soil of three archaic layers, excavated at the archaeological site on Monte Iato (Sicily, Italy) and believed to have been created in a chronological order in archaic times in the context of periodic cultic feasts, were investigated in terms of (i) abundance (phospholipid fatty acid (PLFA) analysis and quantitative PCR)), (ii) carbon(C)-source consumption patterns (Biolog-Ecoplates) and (iii) diversity and community composition (Illumina amplicon sequencing). PLFA analyses demonstrated the existence of living bacteria and fungi in the soil samples of all three layers. The upper layer showed increased levels of organic C, which were not concomitant with an increment in the microbial abundance. In taxonomic terms, the results indicated that bacterial, archaeal and fungal communities were highly diverse, although differences in richness or diversity among the three layers were not detected for any of the communities. However, significantly different microbial C-source utilization patterns and structures of bacterial, archaeal and fungal communities in the three layers confirmed that changing features of soil microbial communities reflect different past human activities.

Effects of application of corn straw on soil microbial community structure during the maize growing season.

PubMed

Lu, Ping; Lin, Yin-Hua; Yang, Zhong-Qi; Xu, Yan-Peng; Tan, Fei; Jia, Xu-Dong; Wang, Miao; Xu, De-Rong; Wang, Xi-Zhuo

2015-01-01

This study investigated the influence of corn straw application on soil microbial communities and the relationship between such communities and soil properties in black soil. The crop used in this study was maize (Zea mays L.). The five treatments consisted of applying a gradient (50, 100, 150, and 200%) of shattered corn straw residue to the soil. Soil samples were taken from May through September during the 2012 maize growing season. The microbial community structure was determined using phospholipid fatty acid (PLFA) analysis. Our results revealed that the application of corn straw influenced the soil properties and increased the soil organic carbon and total nitrogen. Applying corn straw to fields also influenced the variation in soil microbial biomass and community composition, which is consistent with the variations found in soil total nitrogen (TN) and soil respiration (SR). However, the soil carbon-to-nitrogen ratio had no effect on soil microbial communities. The abundance of PLFAs, TN, and SR was higher in C1.5 than those in other treatments, suggesting that the soil properties and soil microbial community composition were affected positively by the application of corn straw to black soil. A Principal Component Analysis indicated that soil microbial communities were different in the straw decomposition processes. Moreover, the soil microbial communities from C1.5 were significantly different from those of CK (p < 0.05). We also found a high ratio of fungal-to-bacterial PLFAs in black soil and significant variations in the ratio of monounsaturated-to-branched fatty acids with different straw treatments that correlated with SR (p < 0.05). These results indicated that the application of corn straw positively influences soil properties and soil microbial communities and that these properties affect these communities. The individual PLFA signatures were sensitive indicators that reflected the changes in the soil environment condition. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Litter Breakdown and Microbial Succession on Two Submerged Leaf Species in a Small Forested Stream

PubMed Central

Newman, Molli M.; Liles, Mark R.; Feminella, Jack W.

2015-01-01

Microbial succession during leaf breakdown was investigated in a small forested stream in west-central Georgia, USA, using multiple culture-independent techniques. Red maple (Acer rubrum) and water oak (Quercus nigra) leaf litter were incubated in situ for 128 days, and litter breakdown was quantified by ash-free dry mass (AFDM) method and microbial assemblage composition using phospholipid fatty acid analysis (PLFA), ribosomal intergenic spacer analysis (RISA), denaturing gradient gel electrophoresis (DGGE), and bar-coded next-generation sequencing of 16S rRNA gene amplicons. Leaf breakdown was faster for red maple than water oak. PLFA revealed a significant time effect on microbial lipid profiles for both leaf species. Microbial assemblages on maple contained a higher relative abundance of bacterial lipids than oak, and oak microbial assemblages contained higher relative abundance of fungal lipids than maple. RISA showed that incubation time was more important in structuring bacterial assemblages than leaf physicochemistry. DGGE profiles revealed high variability in bacterial assemblages over time, and sequencing of DGGE-resolved amplicons indicated several taxa present on degrading litter. Next-generation sequencing revealed temporal shifts in dominant taxa within the phylum Proteobacteria, whereas γ-Proteobacteria dominated pre-immersion and α- and β-Proteobacteria dominated after 1 month of instream incubation; the latter groups contain taxa that are predicted to be capable of using organic material to fuel further breakdown. Our results suggest that incubation time is more important than leaf species physicochemistry in influencing leaf litter microbial assemblage composition, and indicate the need for investigation into seasonal and temporal dynamics of leaf litter microbial assemblage succession. PMID:26098687

Contributions of understory and/or overstory vegetations to soil microbial PLFA and nematode diversities in Eucalyptus monocultures.

PubMed

Zhao, Jie; Wan, Songze; Zhang, Chenlu; Liu, Zhanfeng; Zhou, Lixia; Fu, Shenglei

2014-01-01

Ecological interactions between aboveground and belowground biodiversity have received many attentions in the recent decades. Although soil biodiversity declined with the decrease of plant diversity, many previous studies found plant species identities were more important than plant diversity in controlling soil biodiversity. This study focused on the responses of soil biodiversity to the altering of plant functional groups, namely overstory and understory vegetations, rather than plant diversity gradient. We conducted an experiment by removing overstory and/or understory vegetation to compare their effects on soil microbial phospholipid fatty acid (PLFA) and nematode diversities in eucalyptus monocultures. Our results indicated that both overstory and understory vegetations could affect soil microbial PLFA and nematode diversities, which manifested as the decrease in Shannon-Wiener diversity index (H') and Pielou evenness index (J) and the increase in Simpson dominance index (λ) after vegetation removal. Soil microclimate change explained part of variance of soil biodiversity indices. Both overstory and understory vegetations positively correlated with soil microbial PLFA and nematode diversities. In addition, the alteration of soil biodiversity might be due to a mixing effect of bottom-up control and soil microclimate change after vegetation removal in the studied plantations. Given the studied ecosystem is common in humid subtropical and tropical region of the world, our findings might have great potential to extrapolate to large scales and could be conducive to ecosystem management and service.

Small-scale spatial variability of soil microbial community composition and functional diversity in a mixed forest

NASA Astrophysics Data System (ADS)

Wang, Qiufeng; Tian, Jing; Yu, Guirui

2014-05-01

Patterns in the spatial distribution of organisms provide important information about mechanisms that regulate the diversity and complexity of soil ecosystems. Therefore, information on spatial distribution of microbial community composition and functional diversity is urgently necessary. The spatial variability on a 26×36 m plot and vertical distribution (0-10 cm and 10-20 cm) of soil microbial community composition and functional diversity were studied in a natural broad-leaved Korean pine (Pinus koraiensis) mixed forest soil in Changbai Mountain. The phospholipid fatty acid (PLFA) pattern was used to characterize the soil microbial community composition and was compared with the community substrate utilization pattern using Biolog. Bacterial biomass dominated and showed higher variability than fungal biomass at all scales examined. The microbial biomass decreased with soil depths increased and showed less variability in lower 10-20 cm soil layer. The Shannon-Weaver index value for microbial functional diversity showed higher variability in upper 0-10 cm than lower 10-20 cm soil layer. Carbohydrates, carboxylic acids, polymers and amino acids are the main carbon sources possessing higher utilization efficiency or utilization intensity. At the same time, the four carbon source types contributed to the differentiation of soil microbial communities. This study suggests the higher diversity and complexity for this mix forest ecosystem. To determine the driving factors that affect this spatial variability of microorganism is the next step for our study.

Analysis of phospholipid fatty acids (PLFA) to characterize microbial communities in aquifers

NASA Astrophysics Data System (ADS)

Green, Christopher T.; Scow, Kate M.

This paper reviews published applications of lipid-based biochemical techniques for characterizing microbial communities in aquifers and other deep subsurface habitats. These techniques, such as phospholipid fatty acid (PLFA) analysis, can provide information on a variety of microbial characteristics, such as biomass, physiology, taxonomic and functional identity, and overall community composition. In addition, multivariate statistical analysis of lipid data can relate spatial or temporal changes in microbial communities to environmental factors. The use of lipid-based techniques in the study of groundwater microbiology is advantageous because they do not require culturing and can provide quantitative data on entire communities. However, combined effects of physiological and phylogenetic changes on the lipid composition of a community can confound interpretation of the data, and many questions remain about the validity of various lipid techniques. Despite these caveats, lipid-based research has begun to show trends in community composition in contaminated and pristine aquifers that contribute to our understanding of groundwater microbial ecology and have potential for use in optimization of bioremediation of groundwater pollutants. Résumé Ce papier passe en revue les applications des techniques biochimiques basées sur les lipides pour caractériser les communautés microbiennes présentes dans les aquifères et dans les autres habitats souterrains profonds. Ces techniques, telles que l'analyse des acides gras phospholipidiques (PLFA), peuvent fournir des informations sur un ensemble de caractères microbiens, tels que la biomasse, la physiologie, l'identité taxonomique et fonctionnelle, et surtout la composition de la communauté. En outre, l'analyse statistique multivariée des données sur les lipides peut établir les liens entre des changements spatiaux ou temporels dans la communauté microbienne et des facteurs environnementaux. L'utilisation des techniques basées sur les lipides dans l'étude de la microbiologie des eaux souterraines est intéressante parce qu'elle ne nécessite pas de mise en culture et qu'elle peut fournir des données quantitatives sur les communautés dans leur ensemble. Toutefois, les effets combinés de changements physiologiques et phylogénétiques sur la composition d'une communauté peuvent brouiller l'interprétation des données de nombreuses questions se posent sur la validité des différentes techniques lipidiques. Malgré ces oppositions, la recherche basée sur les lipides a commencéà montrer des tendances dans la composition des communautés dans les aquifères pollués et dans ceux non perturbés ces résultats contribuent ainsi à notre compréhension de l'écologie microbienne des eaux souterraines et montrent qu'il existe un potentiel pour leur utilisation en vue d'une optimisation de la dépollution biologique des eaux souterraines. Resumen Se revisan distintas técnicas bioquímicas que se basan en el análisis de lípidos para caracterizar las comunidades microbianas en hábitats subsuperficiales, incluyendo acuíferos. Estas técnicas, entre las que se incluye el análisis de ácidos grasos fosfolípidos (PLFA), pueden proporcionar información sobre toda una serie de características de las comunidades microbianas, como su biomasa, fisiología, identidad taxonómica y funcional y composición. Además, el análisis estadístico multivariado de los datos de lípidos permite relacionar los cambios espaciales o temporales en las comunidades microbianas con factores ambientales. Las técnicas basadas en lípidos son muy útiles para el estudio microbiológico de las aguas subterráneas, puesto que no requieren cultivos y además proporcionan datos cuantitativos de comunidades completas. Sin embargo, la acción combinada de los cambios fisiológicos y filogenéticos en la composición de lípidos en una comunidad pueden confundir la interpretación de los datos, por lo existen muchas cuestiones abiertas respecto a la validez de algunas de estas técnicas. A pesar de estas dificultades, estas técnicas han permitido detectar diferentes tendencias en la composición de las comunidades en acuíferos con y sin contaminación, lo que contribuye a nuestro entendimiento de la ecología microbiana de los acuíferos. Este último aspecto tiene un uso potencial en la optimización de los métodos de biorremediación de acuíferos.

Spatial distribution of microbial biomass, activity, community structure, and the biodegradation of linear alkylbenzene sulfonate (LAS) and linear alcohol ethoxylate (LAE) in the subsurface.

PubMed

Federle, T W; Ventullo, R M; White, D C

1990-12-01

The vertical distribution of microbial biomass, activity, community structure and the mineralization of xenobiotic chemicals was examined in two soil profiles in northern Wisconsin. One profile was impacted by infiltrating wastewater from a laundromat, while the other served as a control. An unconfined aquifer was present 14 meters below the surface at both sites. Biomass and community structure were determined by acridine orange direct counts and measuring concentrations of phospholipid-derived fatty acids (PLFA). Microbial activity was estimated by measuring fluorescein diacetate (FDA) hydrolysis, thymidine incorporation into DNA, and mixed amino acid (MAA) mineralization. Mineralization kinetics of linear alkylbenzene sulfonate (LAS) and linear alcohol ethoxylate (LAE) were determined at each depth. Except for MAA mineralization rates, measures of microbial biomass and activity exhibited similar patterns with depth. PLFA concentration and rates of FDA hydrolysis and thymidine incorporation decreased 10-100 fold below 3 m and then exhibited little variation with depth. Fungal fatty acid markers were found at all depths and represented from 1 to 15% of the total PLFAs. The relative proportion of tuberculostearic acid (TBS), an actinomycete marker, declined with depth and was not detected in the saturated zone. The profile impacted by wastewater exhibited higher levels of PLFA but a lower proportion of TBS than the control profile. This profile also exhibited faster rates of FDA hydrolysis and amino acid mineralization at most depths. LAS was mineralized in the upper 2 m of the vadose zone and in the saturated zone of both profiles. Little or no LAS biodegradation occurred at depths between 2 and 14 m. LAE was mineralized at all depths in both profiles, and the mineralization rate exhibited a similar pattern with depth as biomass and activity measurements. In general, biomass and biodegradative activities were much lower in groundwater than in soil samples obtained from the same depth.

[Influence of Submerged Plants on Microbial Community Structure in Sediment of Hongze Lake].

PubMed

Zhang, Ding-yu; Zhang, Ting-xi; Dong, Dan-ping; Li, De-fang; Wang, Guo-xiang

2016-05-15

Phospholipid fatty acids (PLFAs) method was applied to analyze the influence of submerged plants on sediment microbial community structure, in order to investigate the changes of sediment microbial community structure for different kinds of the submerged plants in different growth periods. Particularly, Potamogeton crispus L., Potamogeton pectinatus L and the mixed group were chosen as the typical submerged plants in Hongze Lake for investigation in this paper. The results indicated that the change of total PLFAs in different periods was significant, on the contrary, the PLFA change for different groups in the same period was insignificant. The values of G⁺ PLFA/G⁻ PLFA in the submerged plant group were also highly related to the different growth periods, which demonstrated that the root function of the submerged plant had a severe impact on the microbial community in sediment. Furthermore, some environmental factors, such as Temperature, pH, TOC and DO, were correlated to characteristic phospholipid of PLFAs in sediment, which means the environmental factors could also affect the microbial community structure.

Mangrove succession enriches the sediment microbial community in South China

PubMed Central

Chen, Quan; Zhao, Qian; Li, Jing; Jian, Shuguang; Ren, Hai

2016-01-01

Sediment microorganisms help create and maintain mangrove ecosystems. Although the changes in vegetation during mangrove forest succession have been well studied, the changes in the sediment microbial community during mangrove succession are poorly understood. To investigate the changes in the sediment microbial community during succession of mangroves at Zhanjiang, South China, we used phospholipid fatty acid (PLFA) analysis and the following chronosequence from primary to climax community: unvegetated shoal; Avicennia marina community; Aegiceras corniculatum community; and Bruguiera gymnorrhiza + Rhizophora stylosa community. The PLFA concentrations of all sediment microbial groups (total microorganisms, fungi, gram-positive bacteria, gram-negative bacteria, and actinomycetes) increased significantly with each stage of mangrove succession. Microbial PLFA concentrations in the sediment were significantly lower in the wet season than in the dry season. Regression and ordination analyses indicated that the changes in the microbial community with mangrove succession were mainly associated with properties of the aboveground vegetation (mainly plant height) and the sediment (mainly sediment organic matter and total nitrogen). The changes in the sediment microbial community can probably be explained by increases in nutrients and microhabitat heterogeneity during mangrove succession. PMID:27265262

Mangrove succession enriches the sediment microbial community in South China.

PubMed

Chen, Quan; Zhao, Qian; Li, Jing; Jian, Shuguang; Ren, Hai

2016-06-06

Sediment microorganisms help create and maintain mangrove ecosystems. Although the changes in vegetation during mangrove forest succession have been well studied, the changes in the sediment microbial community during mangrove succession are poorly understood. To investigate the changes in the sediment microbial community during succession of mangroves at Zhanjiang, South China, we used phospholipid fatty acid (PLFA) analysis and the following chronosequence from primary to climax community: unvegetated shoal; Avicennia marina community; Aegiceras corniculatum community; and Bruguiera gymnorrhiza + Rhizophora stylosa community. The PLFA concentrations of all sediment microbial groups (total microorganisms, fungi, gram-positive bacteria, gram-negative bacteria, and actinomycetes) increased significantly with each stage of mangrove succession. Microbial PLFA concentrations in the sediment were significantly lower in the wet season than in the dry season. Regression and ordination analyses indicated that the changes in the microbial community with mangrove succession were mainly associated with properties of the aboveground vegetation (mainly plant height) and the sediment (mainly sediment organic matter and total nitrogen). The changes in the sediment microbial community can probably be explained by increases in nutrients and microhabitat heterogeneity during mangrove succession.

Reproduction allocation and potential mechanism of individual allelopathic rice plants in the presence of competing barnyardgrass.

PubMed

Kong, Chui-Hua; Wang, Ming-Li; Wang, Peng; Ni, Han-Wen; Meng, Xiang-Rui

2013-01-01

In spite of increasing knowledge of allelopathic rice as an efficient component involved in paddy weed management, relatively little is known about its reproduction in response to competing weeds. Reproduction allocation of individual allelopathic rice plants in relation to monoculture and mixed culture with competing barnyardgrass in a paddy field was studied, along with analyses of soil nutrients and microbial communities to understand the potential mechanism. At a 1:1 barnyardgrass and rice mixture proportion identified from a replacement series study, biomass, grain yield and major parameters of individual allelopathic rice plants at the mature stage were increased by competing barnyardgrass. There was no difference in allelopathic rice root-zone soil ammonium N and Olsen P between monoculture and mixed culture. However, mixed culture altered soil microbial biomass C and communities. When mixed with barnyardgrass, allelopathic rice root zone had an 87% increase in soil microbial biomass C. Phospholipid fatty acid (PLFA) profiling indicated that the signature lipid biomarkers of bacteria, actinobacteria and fungi were affected by mixed culture. Principal component analysis clearly identified differences in the composition of PLFA in different soil samples. Allelopathic rice specific changes in soil microbial communities may generate a positive feedback on its own growth and reproduction in the presence of competing barnyardgrass in a given paddy system. Copyright © 2012 Society of Chemical Industry.

[Effects of tree species transition on soil microbial community composition and functions in subtropical China].

PubMed

Ding, Guo Chang; Wang, Xiao Hua; Yang, Qi Fan; Lin, Qun Xing; Huang, Zhi Qun

2017-11-01

We employed a comparative study to examine the effects of tree species transition on soil microbial biomass, community composition and enzymes activities under Cunninghamia lanceolata (Lamb.) Hook, Eucalyptus grandis and a N-fixing species, Acacia melanoxylon in subtropical China. Results showed that the effect of tree species on soil microbial community and enzymes activities was significant only in the 0-10 cm soil layer. Reforestation with N-fixing species A. melanoxylon on the C. lanceolata harvest site significantly increased the total phospholipid fatty acid (PLFA), fungal PLFAs, Gram-positive bacterial PLFAs, Gram-negative bacterial PLFAs and actinomycetes biomasses in the 0-10 cm soil layer. The principal component analysis (PCA) showed that the soil microbial community composition in A. melanoxylon soil differed significantly from that in C. lanceolata and E. grandis soils. N-fixing species (A. melanoxylon) significantly enhanced the percent abundance of Gram-positive bacteria, Gram-negative bacteria and actinomycetes. Activities of cellobiohydrolase, N-acetyl-β-d-glucosaminidase and acid phosphatase were significantly higher under A. melanoxylon than under C. lanceolata and E. grandis plantations. Our results suggested that reforestation with N-fixing species, A. melanoxylon on C. lanceolata harvest site could increase soil microbial biomass, enzyme activities and soil organic matter content.

Long-term litter manipulation alters soil organic matter turnover in a temperate deciduous forest.

PubMed

Wang, Jun-Jian; Pisani, Oliva; Lin, Lisa H; Lun, Olivia O Y; Bowden, Richard D; Lajtha, Kate; Simpson, André J; Simpson, Myrna J

2017-12-31

Understanding soil organic matter (OM) biogeochemistry at the molecular-level is essential for assessing potential impacts from management practices and climate change on shifts in soil carbon storage. Biomarker analyses and nuclear magnetic resonance (NMR) spectroscopy were used in an ongoing detrital input and removal treatment experiment in a temperate deciduous forest in Pennsylvania, USA, to examine how above- and below-ground plant inputs control soil OM quantity and quality at the molecular-level. From plant material to surface soils, the free acyclic lipids and cutin, suberin, and lignin biomarkers were preferentially retained over free sugars and free cyclic lipids. After 20years of above-ground litter addition (Double Litter) or exclusion (No Litter) treatments, soil OM composition was relatively more degraded, as revealed by solid-state 13 C NMR spectroscopy. Under Doubled Litter inputs, soil carbon and phospholipid fatty acid (PLFA) concentrations were unchanged, suggesting that the current OM degradation status is a reflection of microbial-mediated degradation that occurred prior to the 20-year sampling campaign. Soil OM degradation was higher in the No Litter treatments, likely due to the decline in fresh, above-ground litter inputs over time. Furthermore, root and root and litter exclusion treatments (No Roots and No Inputs, respectively) both significantly reduced free sugars and PLFAs and increased preservation of suberin-derived compounds. PLFA stress ratios and the low N-acetyl resonances from diffusion edited 1 H NMR also indicate substrate limitations and reduced microbial biomass with these treatments. Overall, we highlight that storage of soil carbon and its biochemical composition do not linearly increase with plant inputs because the microbial processing of soil OM is also likely altered in the studied forest. Copyright © 2017 Elsevier B.V. All rights reserved.

Biochar affects soil organic matter cycling and microbial functions but does not alter microbial community structure in a paddy soil.

PubMed

Tian, Jing; Wang, Jingyuan; Dippold, Michaela; Gao, Yang; Blagodatskaya, Evgenia; Kuzyakov, Yakov

2016-06-15

The application of biochar (BC) in conjunction with mineral fertilizers is one of the most promising management practices recommended to improve soil quality. However, the interactive mechanisms of BC and mineral fertilizer addition affecting microbial communities and functions associated with soil organic matter (SOM) cycling are poorly understood. We investigated the SOM in physical and chemical fractions, microbial community structure (using phospholipid fatty acid analysis, PLFA) and functions (by analyzing enzymes involved in C and N cycling and Biolog) in a 6-year field experiment with BC and NPK amendment. BC application increased total soil C and particulate organic C for 47.4-50.4% and 63.7-74.6%, respectively. The effects of BC on the microbial community and C-cycling enzymes were dependent on fertilization. Addition of BC alone did not change the microbial community compared with the control, but altered the microbial community structure in conjunction with NPK fertilization. SOM fractions accounted for 55% of the variance in the PLFA-related microbial community structure. The particulate organic N explained the largest variation in the microbial community structure. Microbial metabolic activity strongly increased after BC addition, particularly the utilization of amino acids and amines due to an increase in the activity of proteolytic (l-leucine aminopeptidase) enzymes. These results indicate that microorganisms start to mine N from the SOM to compensate for high C:N ratios after BC application, which consequently accelerate cycling of stable N. Concluding, BC in combination with NPK fertilizer application strongly affected microbial community composition and functions, which consequently influenced SOM cycling. Copyright © 2016 Elsevier B.V. All rights reserved.

Competition between roots and microorganisms for phosphorus: A novel 33P labeling approach

NASA Astrophysics Data System (ADS)

Zilla, Thomas; Kuzyakov, Yakov; Zavišiæ, Aljoša; Polle, Andrea

2015-04-01

While organic N mineralization exhibits clear seasonal uptake dynamics, knowledge about seasonal variation in microbial P uptake and mineralization is scarce. We hypothesize that the dynamics of P uptake and mineralization by microorganisms in temperate forest soils exhibit a seasonality anti-cyclic to plant P uptake. Therefore, the ratio of microbial P to labile P increases by the transition from acquiring ecosystems (in spring) to recycling ones (in fall). To investigate this, intact soil-plant mesocosms containing Ah horizon with 1 year old F. sylvatica were removed from the P-rich field site Bad Brueckenau and the P-depleted field site Luess in Germany. During incubation under controlled conditions, seasonal pulse labeling by 33P-orthophosphate was performed at 5 time points over the course of one year. 33P recovery in microbial compounds of organic and mineral soil horizons was determined 7 and 30 days after the labeling. This procedure will account for temporal changes in P allocation and also considers the rather slow P transport from the mycorrhiza into the plants and other microorganisms. For the first time we analyzed the 33P incorporation into total PLFA and consequently provide a new technique for the analysis of P uptake by microorganisms, which has clear advantages compared to P quantification after chloroform fumigation. Polar lipids are hereby extracted with a Frostegård-modified Bligh-and-Dyer buffer, i.e. a single phase mixture of chloroform, methanol and citrate buffer (0.8:1:2, v:v:v). Phospholipids (PLFA) are isolated and purified by solid phase extraction via a silica gel column chromatography. Subsequently, PLFA are hydrolyzed and the resulting fatty acids derivatized by methylation. The fatty acid methyl esters were extracted with n-hexane and measured by GC/MS to investigate the composition of the microbial community. The remaining extract, containing head groups, phosphate units and glycerol backbones, was used to determine 33P activity and recovery in the microbial membrane lipids with a multi-purpose scintillation counter. This approach offers the unique possibility to quantify P fluxes through the microbial network. For the first time, P cycling can be linked to changes in microbial community structure and activity in soils in situ.

Changes in microbial community characteristics and soil organic matter with nitrogen additions in two tropical forests.

PubMed

Cusack, Daniela F; Silver, Whendee L; Torn, Margaret S; Burton, Sarah D; Firestone, Mary K

2011-03-01

Microbial communities and their associated enzyme activities affect the amount and chemical quality of carbon (C) in soils. Increasing nitrogen (N) deposition, particularly in N-rich tropical forests, is likely to change the composition and behavior of microbial communities and feed back on ecosystem structure and function. This study presents a novel assessment of mechanistic links between microbial responses to N deposition and shifts in soil organic matter (SOM) quality and quantity. We used phospholipid fatty acid (PLFA) analysis and microbial enzyme assays in soils to assess microbial community responses to long-term N additions in two distinct tropical rain forests. We used soil density fractionation and 13C nuclear magnetic resonance (NMR) spectroscopy to measure related changes in SOM pool sizes and chemical quality. Microbial biomass increased in response to N fertilization in both tropical forests and corresponded to declines in pools of low-density SOM. The chemical quality of this soil C pool reflected ecosystem-specific changes in microbial community composition. In the lower-elevation forest, there was an increase in gram-negative bacteria PLFA biomass, and there were significant losses of labile C chemical groups (O-alkyls). In contrast, the upper-elevation tropical forest had an increase in fungal PLFAs with N additions and declines in C groups associated with increased soil C storage (alkyls). The dynamics of microbial enzymatic activities with N addition provided a functional link between changes in microbial community structure and SOM chemistry. Ecosystem-specific changes in microbial community composition are likely to have far-reaching effects on soil carbon storage and cycling. This study indicates that microbial communities in N-rich tropical forests can be sensitive to added N, but we can expect significant variability in how ecosystem structure and function respond to N deposition among tropical forest types.

Short-term bioavailability of carbon in soil organic matter fractions of different particle sizes and densities in grassland ecosystems.

PubMed

Breulmann, Marc; Masyutenko, Nina Petrovna; Kogut, Boris Maratovich; Schroll, Reiner; Dörfler, Ulrike; Buscot, François; Schulz, Elke

2014-11-01

The quality, stability and availability of organic carbon (OC) in soil organic matter (SOM) can vary widely between differently managed ecosystems. Several approaches have been developed for isolating SOM fractions to examine their ecological roles, but links between the bioavailability of the OC of size-density fractions and soil microbial communities have not been previously explored. Thus, in the presented laboratory study we investigated the potential bioavailability of OC and the structure of associated microbial communities in different particle-size and density fractions of SOM. For this we used samples from four grassland ecosystems with contrasting management intensity regimes and two soil types: a Haplic Cambisol and a typical Chernozem. A combined size-density fractionation protocol was applied to separate clay-associated SOM fractions (CF1, <1 μm; CF2, 1-2 μm) from light SOM fractions (LF1, <1.8 g cm(-3); LF2, 1.8-2.0 g cm(-3)). These fractions were used as carbon sources in a respiration experiment to determine their potential bioavailability. Measured CO2-release was used as an index of substrate accessibility and linked to the soil microbial community structure, as determined by phospholipid fatty acids (PLFA) analysis. Several key factors controlling decomposition processes, and thus the potential bioavailability of OC, were identified: management intensity and the plant community composition of the grasslands (both of which affect the chemical composition and turnover of OC) and specific properties of individual SOM fractions. The PLFA patterns highlighted differences in the composition of microbial communities associated with the examined grasslands, and SOM fractions, providing the first broad insights into their active microbial communities. From observed interactions between abiotic and biotic factors affecting the decomposition of SOM fractions we demonstrate that increasing management intensity could enhance the potential bioavailability of OC, not only in the active and intermediate SOM pools, but also in the passive pool. Copyright © 2014 Elsevier B.V. All rights reserved.

Nitrogen Addition Regulates Soil Nematode Community Composition through Ammonium Suppression

PubMed Central

Wei, Cunzheng; Zheng, Huifen; Li, Qi; Lü, Xiaotao; Yu, Qiang; Zhang, Haiyang; Chen, Quansheng; He, Nianpeng; Kardol, Paul; Liang, Wenju; Han, Xingguo

2012-01-01

Nitrogen (N) enrichment resulting from anthropogenic activities has greatly changed the composition and functioning of soil communities. Nematodes are one of the most abundant and diverse groups of soil organisms, and they occupy key trophic positions in the soil detritus food web. Nematodes have therefore been proposed as useful indicators for shifts in soil ecosystem functioning under N enrichment. Here, we monitored temporal dynamics of the soil nematode community using a multi-level N addition experiment in an Inner Mongolia grassland. Measurements were made three years after the start of the experiment. We used structural equation modeling (SEM) to explore the mechanisms regulating nematode responses to N enrichment. Across the N enrichment gradient, significant reductions in total nematode abundance, diversity (H' and taxonomic richness), maturity index (MI), and the abundance of root herbivores, fungivores and omnivores-predators were found in August. Root herbivores recovered in September, contributing to the temporal variation of total nematode abundance across the N gradient. Bacterivores showed a hump-shaped relationship with N addition rate, both in August and September. Ammonium concentration was negatively correlated with the abundance of total and herbivorous nematodes in August, but not in September. Ammonium suppression explained 61% of the variation in nematode richness and 43% of the variation in nematode trophic group composition. Ammonium toxicity may occur when herbivorous nematodes feed on root fluid, providing a possible explanation for the negative relationship between herbivorous nematodes and ammonium concentration in August. We found a significantly positive relationship between fungivores and fungal phospholipid fatty acids (PLFA), suggesting bottom-up control of fungivores. No such relationship was found between bacterivorous nematodes and bacterial PLFA. Our findings contribute to the understanding of effects of N enrichment in semiarid grassland on soil nematode trophic groups, and the cascading effects in the detrital soil food web. PMID:22952671

MICROBIAL DIVERSITY IN SURFACE SEDIMENTS: A COMPARISON OF TWO ESTUARINE CONTINUUMS

EPA Science Inventory

The microbial diversity in estuarine sediments of the Altamaha and Savannah Rivers in Georgia were compared temporally and spatially using phospholipid fatty acid (PLFA) analysis. Surface sediment samples collected along a salinity gradient were also analyzed for ATP, TOC, and C ...

13C-DEPLETED MICROBIAL LIPIDS INDICATE SEASONAL METHANOTROPHIC ACTIVITY IN SHALLOW ESTUARINE SEDIMENTS

EPA Science Inventory

Compound specific isotope analysis was combined with phospholipid fatty acid (PLFA) analysis to identify methanotrophic activity in members of the sedimentary microbial community in the Altamaha and Savannah River estuaries in Georgia. 13C-depleted PLFAs indicate methane utilizat...

Soil Microbial Community Structure and Metabolic Activity of Pinus elliottii Plantations across Different Stand Ages in a Subtropical Area.

PubMed

Wu, Zeyan; Haack, Stacey Elizabeth; Lin, Wenxiong; Li, Bailian; Wu, Linkun; Fang, Changxun; Zhang, Zhixing

2015-01-01

Soil microbes play an essential role in the forest ecosystem as an active component. This study examined the hypothesis that soil microbial community structure and metabolic activity would vary with the increasing stand ages in long-term pure plantations of Pinus elliottii. The phospholipid fatty acids (PLFA) combined with community level physiological profiles (CLPP) method was used to assess these characteristics in the rhizospheric soils of P. elliottii. We found that the soil microbial communities were significantly different among different stand ages of P. elliottii plantations. The PLFA analysis indicated that the bacterial biomass was higher than the actinomycic and fungal biomass in all stand ages. However, the bacterial biomass decreased with the increasing stand ages, while the fungal biomass increased. The four maximum biomarker concentrations in rhizospheric soils of P. elliottii for all stand ages were 18:1ω9c, 16:1ω7c, 18:3ω6c (6,9,12) and cy19:0, representing measures of fungal and gram negative bacterial biomass. In addition, CLPP analysis revealed that the utilization rate of amino acids, polymers, phenolic acids, and carbohydrates of soil microbial community gradually decreased with increasing stand ages, though this pattern was not observed for carboxylic acids and amines. Microbial community diversity, as determined by the Simpson index, Shannon-Wiener index, Richness index and McIntosh index, significantly decreased as stand age increased. Overall, both the PLFA and CLPP illustrated that the long-term pure plantation pattern exacerbated the microecological imbalance previously described in the rhizospheric soils of P. elliottii, and markedly decreased the soil microbial community diversity and metabolic activity. Based on the correlation analysis, we concluded that the soil nutrient and C/N ratio most significantly contributed to the variation of soil microbial community structure and metabolic activity in different stand ages of P. elliottii plantations.

Soil Microbial Community Structure and Metabolic Activity of Pinus elliottii Plantations across Different Stand Ages in a Subtropical Area

PubMed Central

Wu, Zeyan; Haack, Stacey Elizabeth; Lin, Wenxiong; Li, Bailian; Wu, Linkun; Fang, Changxun; Zhang, Zhixing

2015-01-01

Soil microbes play an essential role in the forest ecosystem as an active component. This study examined the hypothesis that soil microbial community structure and metabolic activity would vary with the increasing stand ages in long-term pure plantations of Pinus elliottii. The phospholipid fatty acids (PLFA) combined with community level physiological profiles (CLPP) method was used to assess these characteristics in the rhizospheric soils of P. elliottii. We found that the soil microbial communities were significantly different among different stand ages of P. elliottii plantations. The PLFA analysis indicated that the bacterial biomass was higher than the actinomycic and fungal biomass in all stand ages. However, the bacterial biomass decreased with the increasing stand ages, while the fungal biomass increased. The four maximum biomarker concentrations in rhizospheric soils of P. elliottii for all stand ages were 18:1ω9c, 16:1ω7c, 18:3ω6c (6,9,12) and cy19:0, representing measures of fungal and gram negative bacterial biomass. In addition, CLPP analysis revealed that the utilization rate of amino acids, polymers, phenolic acids, and carbohydrates of soil microbial community gradually decreased with increasing stand ages, though this pattern was not observed for carboxylic acids and amines. Microbial community diversity, as determined by the Simpson index, Shannon-Wiener index, Richness index and McIntosh index, significantly decreased as stand age increased. Overall, both the PLFA and CLPP illustrated that the long-term pure plantation pattern exacerbated the microecological imbalance previously described in the rhizospheric soils of P. elliottii, and markedly decreased the soil microbial community diversity and metabolic activity. Based on the correlation analysis, we concluded that the soil nutrient and C/N ratio most significantly contributed to the variation of soil microbial community structure and metabolic activity in different stand ages of P. elliottii plantations. PMID:26267338

How bioavailable is highly weathered Deepwater Horizon oil?

NASA Astrophysics Data System (ADS)

Bostic, J.; Ziolkowski, L. A.; Reddy, C. M.; Aeppli, C.; Swarthout, B.

2016-02-01

Oiled sand patties continue to be deposited on northern Gulf of Mexico beaches five years after the Deepwater Horizon (DwH) oil spill. It is known that during the first 18 months post-spill, sand patties from DwH were chemically transformed, both biotically and abiotically, from wellhead release to beach deposition. However, the chemically transformed oil, which appears to become more polar over time, is not well understood in regards to its biodegradation potential. Biodegradation exerts a large control on the fate of spilled oil, representing a major conduit for its removal from the environment. To assess the bioavailability of this weathered oil, sand patties were collected from intertidal and supratidal zones of beaches in Florida, Alabama, and Mississippi in July 2015. Microbial biomarkers of the viable community, phospholipid fatty acids (PLFA), were detected on all samples collected. The PLFA distributions (mostly saturated and branched structures) and abundances (2 - 9 x 1013 cells/g sand patty) were similar across sampling locations. The positive correlation between PLFA abundance and surface area to volume ratios of sand patties indicates that microbes are preferentially inhabiting outside surfaces of the patties. We will present data on the radiocarbon (14C) content of PLFA to assess carbon (C) sources assimilated by microbes. 14C of PLFA is a powerful tool for assessing C sources assimilated in this setting. Oil has no 14C (Δ14C= -1000‰) while modern organic matter has relatively abundant 14C (Δ14C= 0‰). Fingerprinting analysis of biomarker ratios using comprehensive two-dimensional gas chromatography will be presented to ascertain if oil originated from DwH. The extent of the chemical transformation of the oil into more polar compounds will also be measured using thin layer chromatography. Results of this investigation aim to determine the bioavailability and ultimate fate of oiled sand patties that continue to wash ashore on Gulf of Mexico beaches.

Effects of different agricultural managements in soil microbial community structure in a semi-arid Mediterranean region.

NASA Astrophysics Data System (ADS)

García-Orenes, Fuensanta; Morugan, Alicia; Mataix-Solera, Jorge; Scow, Kate

2013-04-01

Agriculture has been practiced in semi-arid Mediterranean regions for 10.000 years and in many cases these practices have been unsuitable causing land degradation for millennium and an important loss of soil quality. The land management can provide solutions to find the best agricultural practices in order to maintain the soil quality and get a sustainable agriculture model. Microbiological properties are the most sensitive and rapid indicators of soil perturbations and land use managements. The study of microbial community and diversity has an important interest as indicators of changes in soil quality. The main objective of this work was to asses the effect of different agricultural management practices in soil microbial community (evaluated as abundance of phospholipid fatty acids, PLFA). Four different treatments were selected, based on the most commonly practices applied by farmers in the study area, "El Teularet Experimental Station", located at the Enguera Range in the southern part of the Valencia province (eastern Spain). These treatments were: a) ploughing, b) herbicides c) mulch, using the types applied by organic farmers to develop a sustainable agriculture, such as oat straw and d) control that was established as plot where the treatment was abandonment after farming. An adjacent area with the same type of soil, but with natural vegetation was used as a standard or reference high quality soil. Soil samples were taken to evaluate the changes in microbial soil structure, analysing the abundance of PLFA. The results showed a major content of total PLFA in soils treated with oats straw, being these results similar to the content of PLFA in the soil with natural vegetation, also these soils were similar in the distribution of abundance of different PLFA studied. However, the herbicide and tillage treatments showed great differences regarding the soil used as reference (soil under natural vegetation).

Determination of microbial carbon sources and cycling during remediation of petroleum hydrocarbon impacted soil using natural abundance (14)C analysis of PLFA.

PubMed

Cowie, Benjamin R; Greenberg, Bruce M; Slater, Gregory F

2010-04-01

In a petroleum impacted land-farm soil in Sarnia, Ontario, compound-specific natural abundance radiocarbon analysis identified biodegradation by the soil microbial community as a major pathway for hydrocarbon removal in a novel remediation system. During remediation of contaminated soils by a plant growth promoting rhizobacteria enhanced phytoremediation system (PEPS), the measured Delta(14)C of phospholipid fatty acid (PLFA) biomarkers ranged from -793 per thousand to -897 per thousand, directly demonstrating microbial uptake and utilization of petroleum hydrocarbons (Delta(14)C(PHC) = -1000 per thousand). Isotopic mass balance indicated that more than 80% of microbial PLFA carbon was derived from petroleum hydrocarbons (PHC) and a maximum of 20% was obtained from metabolism of more modern carbon sources. These PLFA from the contaminated soils were the most (14)C-depleted biomarkers ever measured for an in situ environmental system, and this study demonstrated that the microbial community in this soil was subsisting primarily on petroleum hydrocarbons. In contrast, the microbial community in a nearby uncontaminated control soil maintained a more modern Delta(14)C signature than total organic carbon (Delta(14)C(PLFA) = +36 per thousand to -147 per thousand, Delta(14)C(TOC) = -148 per thousand), indicating preferential consumption of the most modern plant-derived fraction of soil organic carbon. Measurements of delta(13)C and Delta(14)C of soil CO(2) additionally demonstrated that mineralization of PHC contributed to soil CO(2) at the contaminated site. The CO(2) in the uncontaminated control soil exhibited substantially more modern Delta(14)C values, and lower soil CO(2) concentrations than the contaminated soils, suggesting increased rates of soil respiration in the contaminated soils. In combination, these results demonstrated that biodegradation in the soil microbial community was a primary pathway of petroleum hydrocarbon removal in the PEPS system. This study highlights the power of natural abundance radiocarbon for determining microbial carbon sources and identifying biodegradation pathways in complex remediation systems.

Chemoautotrophic carbon fixation rates and active bacterial communities in intertidal marine sediments.

PubMed

Boschker, Henricus T S; Vasquez-Cardenas, Diana; Bolhuis, Henk; Moerdijk-Poortvliet, Tanja W C; Moodley, Leon

2014-01-01

Chemoautotrophy has been little studied in typical coastal marine sediments, but may be an important component of carbon recycling as intense anaerobic mineralization processes in these sediments lead to accumulation of high amounts of reduced compounds, such as sulfides and ammonium. We studied chemoautotrophy by measuring dark-fixation of 13C-bicarbonate into phospholipid derived fatty acid (PLFA) biomarkers at two coastal sediment sites with contrasting sulfur chemistry in the Eastern Scheldt estuary, The Netherlands. At one site where free sulfide accumulated in the pore water right to the top of the sediment, PLFA labeling was restricted to compounds typically found in sulfur and ammonium oxidizing bacteria. At the other site, with no detectable free sulfide in the pore water, a very different PLFA labeling pattern was found with high amounts of label in branched i- and a-PLFA besides the typical compounds for sulfur and ammonium oxidizing bacteria. This suggests that other types of chemoautotrophic bacteria were also active, most likely Deltaproteobacteria related to sulfate reducers. Maximum rates of chemoautotrophy were detected in first 1 to 2 centimeters of both sediments and chemosynthetic biomass production was high ranging from 3 to 36 mmol C m(-2) d(-1). Average dark carbon fixation to sediment oxygen uptake ratios were 0.22±0.07 mol C (mol O2)(-1), which is in the range of the maximum growth yields reported for sulfur oxidizing bacteria indicating highly efficient growth. Chemoautotrophic biomass production was similar to carbon mineralization rates in the top of the free sulfide site, suggesting that chemoautotrophic bacteria could play a crucial role in the microbial food web and labeling in eukaryotic poly-unsaturated PLFA was indeed detectable. Our study shows that dark carbon fixation by chemoautotrophic bacteria is a major process in the carbon cycle of coastal sediments, and should therefore receive more attention in future studies on sediment biogeochemistry and microbial ecology.

Assessing microbial utilization of free versus sorbed Alanine by using position-specific 13C labeling and 13C-PLFA analysis

NASA Astrophysics Data System (ADS)

Herschbach, Jennifer; Apostel, Carolin; Spielvogel, Sandra; Kuzyakov, Yakov; Dippold, Michaela

2016-04-01

Microbial utilization is a key transformation process of soil organic matter (SOM). Sorption of low molecular weight organic substances (LMWOS) to soil mineral surfaces blocks or delays microbial uptake and therefore mineralization of LMWOS to CO2, as well as all other biochemical transformations. We used position-specific labeling, a tool of isotope applications novel to soil science, combined with 13C-phospholipid fatty acid (PLFA) analysis, to assess microbial utilization of sorbed and non-sorbed Alanine in soil. Alanine has various functional groups enabling different sorption mechanisms via its positive charge (e.g. to clay minerals by cation exchange), as well as via its negative charge (e.g. to iron oxides by ligand exchange). To assess changes in the transformation pathways caused by sorption, we added uniformly and position-specifically 13C and 14C labeled Alanine to the Ap of a loamy Luvisol in a short-term (10 days) incubation experiment. To allow for sorption of the tracer solution to an aliquot of this soil, microbial activity was minimized in this subsample by sterilizing the soil by γ-radiation. After shaking, the remaining solutions were filtered and the non-sorbed Alanine was removed with Millipore water and then added to non-sterilized soil. For the free Alanine treatment, solutions with Alanine of similar amount and isotopic composition were prepared, added to the soil and incubated as well. The respired CO2 was trapped in NaOH and its 14C-activity was determined at increasing times intervals. Microbial utilization of Alanine's individual C positions was evaluated in distinct microbial groups classified by 13C-PLFA analysis. Sorption to soil minerals delayed respiration to CO2 and reduced initial respiration rate by 80%. Irrespective of sorption, the highest amount was respired from the carboxylic position (C-1), whereas the amino-bound (C-2) and the methylic position (C-3) were preferentially incorporated into PLFA of microorganisms due to the basic microbial metabolism of C3 molecules in glycolysis. Reconstruction of microbial transformation pathways showed that the C-2 position of Alanine was lost as CO2 faster than its C-3 position regardless of whether the molecule was used ana- or catabolically. The highest incorporations of all positions in PLFA were accomplished by Gram negatives. Free Alanine was preferentially used by highly competitive prokaryotes, while sorbed Alanine was preferred by filamentous microorganisms. In detail, the free living osmotrophic Gram negative bacteria utilize more easily accessible dissolved substances. The utilization of sorbed substances are achieved by less mobile microorganisms, e.g. eukaryotic fungi and Actinomycetes, which form biofilms. None of these findings could have been achieved without the position-specific labeling approach, therefore this method will strongly improve our understanding of stabilization processes and soil C fluxes.

Supercritical Fluid Extraction of Bacterial and Archaeal Lipid Biomarkers from Anaerobically Digested Sludge

PubMed Central

Hanif, Muhammad; Atsuta, Yoichi; Fujie, Koichi; Daimon, Hiroyuki

2012-01-01

Supercritical fluid extraction (SFE) was used in the analysis of bacterial respiratory quinone (RQ), bacterial phospholipid fatty acid (PLFA), and archaeal phospholipid ether lipid (PLEL) from anaerobically digested sludge. Bacterial RQ were determined using ultra performance liquid chromatography (UPLC). Determination of bacterial PLFA and archaeal PLEL was simultaneously performed using gas chromatography-mass spectrometry (GC-MS). The effects of pressure, temperature, and modifier concentration on the total amounts of RQ, PLFA, and PLEL were investigated by 23 experiments with five settings chosen for each variable. The optimal extraction conditions that were obtained through a multiple-response optimization included a pressure of 23.6 MPa, temperature of 77.6 °C, and 10.6% (v/v) of methanol as the modifier. Thirty nine components of microbial lipid biomarkers were identified in the anaerobically digested sludge. Overall, the SFE method proved to be more effective, rapid, and quantitative for simultaneously extracting bacterial and archaeal lipid biomarkers, compared to conventional organic solvent extraction. This work shows the potential application of SFE as a routine method for the comprehensive analysis of microbial community structures in environmental assessments using the lipid biomarkers profile. PMID:22489140

Biomass, community structure and nutritional status attributes of the deep subsurface microbiota---at Idaho and Hanford sites

DOE Office of Scientific and Technical Information (OSTI.GOV)

White, D.C.; Ringelberg, D.B.

1991-10-28

The signature lipid biomarker technique based on phospholipid ester-linked fatty acid pattern analysis (PLFA) provides data on the total viable or potentially viable communities without the necessity of: (1) Quantitative recovery from the sediments or (2) The ability to culture the organisms. Analysis of PLFA provides evidence for the nutritional status (starvation and/or unbalanced growth) in situ. PLFA analysis of SSP samples from the INEL and PNL sites vadose zones showed higher biomass at the surface with prominent Actinomyces biomarkers with lower biomasses of stressed microbiota at progressively greater depth. The biomass and community diversity increased at the water tablemore » at both sites. Both these Western sites showed lower viable microbial biomasses than the WSRS samples. Cluster analysis of the total patterns from various sedimentary horizons showed three major consortia of microbes, with surface microbiota related at both sites, low viable biomass sites closely related at both sites, with anaerobic desaturase pathway being predominant at INEL and consortia utilizing predominantly branched saturated and the aerobic desaturase pathway at both sites. Preliminary examination of the consortia recovered from NTS show a clear relationship to water level.« less

Temporal dynamics of the compositions and activities of soil microbial communities post-application of the insecticide chlorantraniliprole in paddy soils.

PubMed

Wu, Meng; Liu, Jia; Li, Weitao; Liu, Ming; Jiang, Chunyu; Li, Zhongpei

2017-10-01

Chlorantraniliprole (CAP) is a newly developed insecticide widely used in rice fields in China. There has been few studies evaluating the toxicological effects of CAP on soil-associated microbes. An 85-day microcosm experiment was performed to reveal the dissipation dynamics of CAP in three types of paddy soils in subtropical China. The effects of CAP on microbial activities (microbial biomass carbon-MBC, basal soil respiration-BSR, microbial metabolic quotient-qCO 2 , acid phosphatase and sucrose invertase activities) in the soils were periodically evaluated. Microbial phospholipid fatty acid (PLFA) analysis was used to evaluate the change of soil microbial community composition on day 14 and 50 of the experiment. CAP residues were extracted using the quick, easy, cheap, effective, rugged, and safe (QuChERS) method and quantification was measured by high performance liquid chromatography (HPLC). The half-lives (DT 50 ) of CAP were in the range of 41.0-53.0 days in the three soils. The results showed that CAP did not impart negative effects on MBC during the incubation. CAP inhibited BSR, qCO 2 , acid phosphatase and sucrose invertase activities in the first 14 days of incubation in all the soils. After day 14, the soil microbial parameters of CAP-treated soils became statistically at par with their controls. Principal component analysis (PCA) determining abundance of biomarker PLFAs indicated that the application of CAP significantly changed the compositions of microbial communities in all three paddy soils on day 14 but the compositions of soil microbial communities recovered by day 50. This study indicates that CAP does not ultimately impair microbial activities and microbial compositions of these three paddy soil types. Copyright © 2017 Elsevier Inc. All rights reserved.

Key factors controlling microbial community response after a fire: importance of severity and recurrence

NASA Astrophysics Data System (ADS)

Lombao, Alba; Barreiro, Ana; Martín, Ángela; Díaz-Raviña, Montserrat

2015-04-01

Microorganisms play an important role in forest ecosystems, especially after fire when vegetation is destroyed and soil is bared. Fire severity and recurrence might be one of main factors controlling the microbial response after a wildfire but information about this topic is scarce. The aim of this study is to evaluate the influence of fire regimen (recurrence and severity) on soil microbial community structure by means of the analysis of phospholipid fatty acid (PLFA). The study was performed with unburned and burned samples collected from the top layer of a soil affected by a high severity fire (Laza, NW Spain) heated under laboratory conditions at different temperatures (50°C, 75°C, 100°C, 125°C, 150°C, 175°C, 200°C, 300°C) to simulate different fire intensities; the process was repeated after further soil recovery (1 month incubation) to simulate fire recurrence. The soil temperature was measured with thermocouples and used to calculate the degree-hours as estimation of the amount of heat supplied to the samples (fire severity). The PLFA analysis was used to estimate total biomass and the biomass of specific groups (bacteria, fungi, gram-positive bacteria and gram-negative bacteria) as well as microbial community structure (PLFA pattern) and PLFA data were analyzed by means of principal component analysis (PCA) in order to identify main factors determining microbial community structure. The results of PCA, performed with the whole PLFA data set, showed that first component explained 35% of variation and clearly allow us to differentiate unburned samples from the corresponding burned samples, while the second component, explaining 16% of variation, separated samples according the heating temperature. A marked impact of fire regimen on soil microorganisms was detected; the microbial community response varied depending on previous history of soil heating and the magnitude of changes in the PLFA pattern was related to the amount of heat supplied to the samples. Thus, wildfire was the main factor determining the microbial community structure followed, in less extent, by fire severity. The total biomass and the biomass of specifics microbial groups decreased notably as consequence of wildfire and minor changes were detected due to soil heating under laboratory conditions. The results clearly showed the usefulness of PLFA pattern combined with PCA to study the relationships between fire regimen (recurrence and severity) and associated direct and indirect changes in soil microorganisms. The data also indicated that degree-hours methodology rather than temperature is adequate for evaluating the impact of soil heating on microbial communities. Keywords: wildfire, heating temperature, degree-hours, PLFA pattern, microbial biomass Acknowledgements. This study was supported by the Ministerio Español de Economía y Competitividad (AGL2012-39688-C02-01). A Lombao is recipient of FPU grant from Ministerio Español de Educación.

Short-term monitoring of aridland lichen cover and biomass using photography and fatty acids

USGS Publications Warehouse

Bowker, M.A.; Johnson, N.C.; Belnap, J.; Koch, G.W.

2008-01-01

Biological soil crust (BSC) communities (composed of lichens, bryophytes, and cyanobacteria) may be more dynamic on short-time scales than previously thought, requiring new and informative short-term monitoring techniques. We used repeat digital photography and image analysis, which revealed a change in area of a dominant BSC lichen, Collema tenax. The data generated correlated well with gross photosynthesis (r=0.57) and carotenoid content (r=0.53), two variables that would be expected to be positively related to lichen area. We also extracted fatty acids from lichen samples and identified useful phospholipid fatty acid (PLFA) indicators for the Collema mycobiont (20:1, 15:0, 23:0), and the Collema photobiont (18:3??3). The 18:3??3 correlated well with chlorophyll a (r=0.66), a more traditional proxy for cyanobacterial biomass. We also compared total PLFA as a proxy for total Collema biomass with our photographically generated areal change data, and found them to be moderately correlated (r=0.44). Areal change proved to be responsive on short-time scales, while fatty acid techniques were information-rich, providing data on biomass of lichens, and both photo- and mycobionts separately, in addition to the physiological status of the mycobiont. Both techniques should be refined and tested in field situations. ?? 2007 Elsevier Ltd. All rights reserved.

Remediation of DNAPL through Sequential In Situ Chemical Oxidation and Bioaugmentation

DTIC Science & Technology

2009-04-01

Specific Electrode Field Field-filtered, ICP - PSC 0.05 mg/L 125 mL plastic nitric acid to pHɚ 28 days cool to 4oC Ion Chromatography 25310 C PSC 0.2...oxidized by MnO2 at a significant rate; however, MnO2 reacted rapidly with oxalic acid ; • Complete dechlorination occurred only in microcosms...controller PLFA phospholipid fatty acid ppb parts per billion PTA pilot test area PVC polyvinyl chloride QAPP quality assurance project plan QA

Microbial Communities in Cerrado Soils under Native Vegetation Subjected to Prescribed Fires and Under Pasture

EPA Science Inventory

The objective of this work was to evaluate the effects of fire regimes and vegetation cover on the structure and dynamics of soil microbial communities, through phospholipid fatty acid (PLFA) analysis. Comparisons were made between native areas with different woody covers ("cerra...

Enhanced bioavailability of EPA from emulsified fish oil preparations versus capsular triacylglycerol

USDA-ARS?s Scientific Manuscript database

Pre-emulsified fish oil supplements, an alternative to capsular triacylglycerol, may enhance the uptake of LCn3 fatty acids it contains. A randomized, Latin-square crossover design was used to compare the effects of four fish oil supplement preparations on phospholipid (PLFA) and chylomicron fatty ...

Genetic variants in desaturase gene, erythrocyte fatty acids, and risk for type 2 diabetes in Chinese Hans.

PubMed

Huang, Tao; Sun, Jianqin; Chen, Yanqiu; Xie, Hua; Xu, Danfeng; Huang, Jinyan; Li, Duo

2014-01-01

The aim of this study was to examine the association of the genetic variants in the fatty acid desaturase (FADS) gene cluster with erythrocyte phospholipid fatty acids (PLFA), and their relation to risk for type 2 diabetes mellitus (T2DM) in Han Chinese. Seven hundred and fifty-eight patients with T2DM and 400 healthy individuals were recruited. The erythrocyte PLFA and single-nucleotide polymorphism were determined by standard method. Minor allele homozygotes and heterozygotes of rs174575 and rs174537 had lower PL 20:4 ω-6 levels in healthy individuals. Minor allele homozygotes and heterozygotes of rs174455 in FADS3 gene had lower levels of 22:5 ω-3, 20:4 ω-6, and Δ5desaturase activity in patients with T2DM. Erythrocyte membrane PL 18:3 ω-3 (P for trend = 0.002), 22:5 ω-3 (P for trend < 0.001), ω-3 polyunsaturated fatty acid (P for trend < 0.001), and ω-3:ω-6 (P for trend < 0.001) were significantly inversely associated with risk for T2DM. Genetic variants in the FADS gene cluster are associated with altered erythrocyte PLFAs. High levels of PL 18:3 ω-3, 22:5 ω-3, and total ω-3 polyunsaturated fatty acid were associated with low risk for T2DM. Copyright © 2014 Elsevier Inc. All rights reserved.

Contrasting effects of ammonium and nitrate additions on the biomass of soil microbial communities and enzyme activities in subtropical China

NASA Astrophysics Data System (ADS)

Zhang, Chuang; Zhang, Xin-Yu; Zou, Hong-Tao; Kou, Liang; Yang, Yang; Wen, Xue-Fa; Li, Sheng-Gong; Wang, Hui-Min; Sun, Xiao-Min

2017-10-01

The nitrate to ammonium ratios in nitrogen (N) compounds in wet atmospheric deposits have increased over the recent past, which is a cause for some concern as the individual effects of nitrate and ammonium deposition on the biomass of different soil microbial communities and enzyme activities are still poorly defined. We established a field experiment and applied ammonium (NH4Cl) and nitrate (NaNO3) at monthly intervals over a period of 4 years. We collected soil samples from the ammonium and nitrate treatments and control plots in three different seasons, namely spring, summer, and fall, to evaluate the how the biomass of different soil microbial communities and enzyme activities responded to the ammonium (NH4Cl) and nitrate (NaNO3) applications. Our results showed that the total contents of phospholipid fatty acids (PLFAs) decreased by 24 and 11 % in the ammonium and nitrate treatments, respectively. The inhibitory effects of ammonium on Gram-positive bacteria (G+) and bacteria, fungi, actinomycetes, and arbuscular mycorrhizal fungi (AMF) PLFA contents ranged from 14 to 40 % across the three seasons. We also observed that the absolute activities of C, N, and P hydrolyses and oxidases were inhibited by ammonium and nitrate, but that nitrate had stronger inhibitory effects on the activities of acid phosphatase (AP) than ammonium. The activities of N-acquisition specific enzymes (enzyme activities normalized by total PLFA contents) were about 21 and 43 % lower in the ammonium and nitrate treatments than in the control, respectively. However, the activities of P-acquisition specific enzymes were about 19 % higher in the ammonium treatment than in the control. Using redundancy analysis (RDA), we found that the measured C, N, and P hydrolysis and polyphenol oxidase (PPO) activities were positively correlated with the soil pH and ammonium contents, but were negatively correlated with the nitrate contents. The PLFA biomarker contents were positively correlated with soil pH, soil organic carbon (SOC), and total N contents, but were negatively correlated with the ammonium contents. The soil enzyme activities varied seasonally, and were highest in March and lowest in October. In contrast, the contents of the microbial PLFA biomarkers were higher in October than in March and June. Ammonium may inhibit the contents of PLFA biomarkers more strongly than nitrate because of acidification. This study has provided useful information about the effects of ammonium and nitrate on soil microbial communities and enzyme activities.

Biochar modulates heavy metal toxicity and improves microbial carbon use efficiency in soil.

PubMed

Xu, Yilu; Seshadri, Balaji; Sarkar, Binoy; Wang, Hailong; Rumpel, Cornelia; Sparks, Donald; Farrell, Mark; Hall, Tony; Yang, Xiaodong; Bolan, Nanthi

2018-04-15

Soil organic carbon is essential to improve soil fertility and ecosystem functioning. Soil microorganisms contribute significantly to the carbon transformation and immobilisation processes. However, microorganisms are sensitive to environmental stresses such as heavy metals. Applying amendments, such as biochar, to contaminated soils can alleviate the metal toxicity and add carbon inputs. In this study, Cd and Pb spiked soils treated with macadamia nutshell biochar (5% w/w) were monitored during a 49days incubation period. Microbial phospholipid fatty acids (PLFAs) were extracted and analysed as biomarkers in order to identify the microbial community composition. Soil properties, metal bioavailability, microbial respiration, and microbial biomass carbon were measured after the incubation period. Microbial carbon use efficiency (CUE) was calculated from the ratio of carbon incorporated into microbial biomass to the carbon mineralised. Total PLFA concentration decreased to a greater extent in metal contaminated soils than uncontaminated soils. Microbial CUE also decreased due to metal toxicity. However, biochar addition alleviated the metal toxicity, and increased total PLFA concentration. Both microbial respiration and biomass carbon increased due to biochar application, and CUE was significantly (p<0.01) higher in biochar treated soils than untreated soils. Heavy metals reduced the microbial carbon sequestration in contaminated soils by negatively influencing the CUE. The improvement of CUE through biochar addition in the contaminated soils could be attributed to the decrease in metal bioavailability, thereby mitigating the biotoxicity to soil microorganisms. Copyright © 2017 Elsevier B.V. All rights reserved.

Comparison of characterization and microbial communities in rice straw- and wheat straw-based compost for Agaricus bisporus production.

PubMed

Wang, Lin; Mao, Jiugeng; Zhao, Hejuan; Li, Min; Wei, Qishun; Zhou, Ying; Shao, Heping

2016-09-01

Rice straw (RS) is an important raw material for the preparation of Agaricus bisporus compost in China. In this study, the characterization of composting process from RS and wheat straw (WS) was compared for mushroom production. The results showed that the temperature in RS compost increased rapidly compared with WS compost, and the carbon (C)/nitrogen (N) ratio decreased quickly. The microbial changes during the Phase I and Phase II composting process were monitored using denaturing gradient gel electrophoresis (DGGE) and phospholipid fatty acid (PLFA) analysis. Bacteria were the dominant species during the process of composting and the bacterial community structure dramatically changed during heap composting according to the DGGE results. The bacterial community diversity of RS compost was abundant compared with WS compost at stages 4-5, but no distinct difference was observed after the controlled tunnel Phase II process. The total amount of PLFAs of RS compost, as an indicator of microbial biomass, was higher than that of WS. Clustering by DGGE and principal component analysis of the PLFA compositions revealed that there were differences in both the microbial population and community structure between RS- and WS-based composts. Our data indicated that composting of RS resulted in improved degradation and assimilation of breakdown products by A. bisporus, and suggested that the RS compost was effective for sustaining A. bisporus mushroom growth as well as conventional WS compost.

Characterization of contamination, source and degradation of petroleum between upland and paddy fields based on geochemical characteristics and phospholipid fatty acids.

PubMed

Zhang, Juan; Wang, Renqing; Du, Xiaoming; Li, Fasheng; Dai, Jiulan

2012-01-01

To evaluate contamination caused by petroleum, surface soil samples were collected from both upland and paddy fields along the irrigation canals in the Hunpu wastewater irrigation region in northeast China. N-alkanes, terpanes, steranes, and phospholipid fatty acids (PLFA) in the surface soil samples were analyzed. The aliphatic hydrocarbon concentration was highest in the samples obtained from the upland field near an operational oil well; it was lowest at I-3P where wastewater irrigation promoted the downward movement of hydrocarbons. The Hunpu region was found contaminated by heavy petroleum from oxic lacustrine fresh water or marine deltaic source rocks. Geochemical parameters also indicated significantly heavier contamination and degradation in the upland fields compared with the paddy fields. Principal component analysis based on PLFA showed various microbial communities between petroleum contaminated upland and paddy fields. Gram-negative bacteria indicated by 15:0, 3OH 12:0, and 16:1(9) were significantly higher in the paddy fields, whereas Gram-positive bacteria indicated by i16:0 and 18:1(9)c were significantly higher in the upland fields (p < 0.05). These PLFAs were related to petroleum contamination. Poly-unsaturated PLFA (18:2omega6, 9; indicative of hydrocarbon-degrading bacteria and fungi) was also significantly elevated in the upland fields. This paper recommends more sensitive indicators of contamination and degradation of petroleum in soil. The results also provide guidelines on soil pollution control and remediation in the Hunpu region and other similar regions.

ACCUMULATION OF POLY-B-HYDROXYBUTYRATE IN A METHANE- ENRICHED, HALOGENATED, HYDROCARBON-DEGRADING SOIL COLUMN: IMPLICATIONS FOR MICROBIAL COMMUNITY STRUCTURE AND NUTRITIONAL STATUS

EPA Science Inventory

The prokarotic, endogenous storage polymer poly--hydroxybutyrate (PHB) accumulated in soil from a methane-enriched, halogenated hydrocarbon-degrading soil column. Based on phospholipid ester-linked fatty acid (PLFA) profiles, this mocrocosm has been previously reported to be sign...

Microsite and time since prescribed fire's influence on soil microbiology in a pinyon woodland

Treesearch

Benjamin M. Rau; Robert R. Blank; Tye Morgan

2008-01-01

Pinyon-juniper (Pinus monophylla Torr. & Frém.? Juniperus osteosperma Torr.) encroachment into sagebrush grasslands is a continuing problem in the Western United States. Prescribed burning has been suggested to slow woodland encroachment. We examined surface soil microbial community structure using Phospholipid Fatty Acid (PLFA...

Effects and risk assessment of linear alkylbenzene sulfonates in agricultural soil. 1. Short-term effects on soil microbiology.

PubMed

Elsgaard, L; Petersen, S O; Debosz, K

2001-08-01

Linear alkylbenzene sulfonates (LAS) may occur in sewage sludge that is applied to agricultural soil, in which LAS can be inhibitory to biological activity. As a part of a broader risk assessment of LAS in the terrestrial environment, we tested the short-term effects of aqueous LAS on microbial parameters in a sandy agricultural soil that was incubated for up to 11 d. The assays included 10 microbial soil parameters; ethylene degradation; potential ammonium oxidation; potential dehydrogenase activity; beta-glucosidase activity; iron reduction; the populations of cellulolytic bacteria, fungi and actinomycetes; the basal soil respiration; and the phospholipid fatty acid (PLFA) content. Except for beta-glucosidase activity, basal respiration, and total PLFA content, all soil parameters were sensitive to LAS, with EC10 values in the range of less than 8 to 22 mg/kg dry weight. This probably reflected a similar mode of LAS toxicity, ascribed to cell membrane interactions, and showed that sensitivity to LAS was common for various soil microorganisms. The extracellular beta-glucosidase activity was rather insensitive to LAS (ECI10, 47 mg/kg dry wt), whereas the basal soil respiration was not inhibited even at 793 mg/kg dry weight. This was interpreted as a combined response of inhibited and stimulated compartments of the microbial community. The PLFA content, surprisingly, showed no decrease even at 488 mg/kg. In conclusion, LAS inhibited specific microbial activities, although this could not be deduced from the basal respiration or the total PLFA content. The lowest EC10 values for microbial soil parameters were slightly higher than the predicted no-effect concentrations recently derived for plants and soil fauna (approximately 5 mg/kg dry wt).

Plasma phospholipid fatty acid profile confirms compliance to a novel saturated fat-reduced, monounsaturated fat-enriched dairy product intervention in adults at moderate cardiovascular risk: a randomized controlled trial.

PubMed

Markey, Oonagh; Vasilopoulou, Dafni; Kliem, Kirsty E; Koulman, Albert; Fagan, Colette C; Summerhill, Keith; Wang, Laura Y; Grandison, Alistair S; Humphries, David J; Todd, Susan; Jackson, Kim G; Givens, David I; Lovegrove, Julie A

2017-05-23

Dairy products are a major contributor to dietary SFA. Partial replacement of milk SFA with unsaturated fatty acids (FAs) is possible through oleic-acid rich supplementation of the dairy cow diet. To assess adherence to the intervention of SFA-reduced, MUFA-enriched dairy product consumption in the RESET (REplacement of SaturatEd fat in dairy on Total cholesterol) study using 4-d weighed dietary records, in addition to plasma phospholipid FA (PL-FA) status. In a randomised, controlled, crossover design, free-living UK participants identified as moderate risk for CVD (n = 54) were required to replace habitually consumed dairy foods (milk, cheese and butter), with study products with a FA profile typical of retail products (control) or SFA-reduced, MUFA-enriched profile (modified), for two 12-week periods, separated by an 8-week washout period. A flexible food-exchange model was used to implement each isoenergetic high-fat, high-dairy diet (38% of total energy intake (%TE) total fat): control (dietary target: 19%TE SFA; 11%TE MUFA) and modified (16%TE SFA; 14%TE MUFA). Following the modified diet, there was a smaller increase in SFA (17.2%TE vs. 19.1%TE; p < 0.001) and greater increase in MUFA intake (15.4%TE vs. 11.8%TE; p < 0.0001) when compared with the control. PL-FA analysis revealed lower total SFAs (p = 0.006), higher total cis-MUFAs and trans-MUFAs (both p < 0.0001) following the modified diet. The food-exchange model was successfully used to achieve RESET dietary targets by partial replacement of SFAs with MUFAs in dairy products, a finding reflected in the PL-FA profile and indicative of objective dietary compliance. ClinicalTrials.gov Identifier: NCT02089035 , date 05-01-2014.

Effect of rhizosphere on soil microbial community and in-situ pyrene biodegradation

USGS Publications Warehouse

Su, Y.; Yang, X.; Chiou, C.T.

2008-01-01

To access the influence of a vegetation on soil microorganisms toward organic pollutant biogegration, this study examined the rhizospheric effects of four plant species (sudan grass, white clover, alfalfa, and fescue) on the soil microbial community and in-situ pyrene (PYR) biodegradation. The results indicated that the spiked PYR levels in soils decreased substantially compared to the control soil without planting. With equal planted densities, the efficiencies of PYR degradation in rhizosphere with sudan grass, white clover, alfalfa and fescue were 34.0%, 28.4%, 27.7%, and 9.9%, respectively. However, on the basis of equal root biomass the efficiencies were in order of white clover >> alfalfa > sudan > fescue. The increased PYR biodegradation was attributed to the enhanced bacterial population and activity induced by plant roots in the rhizosphere. Soil microbial species and biomasses were elucidated in terms of microbial phospholipid ester-linked fatty acid (PLFA) biomarkers. The principal component analysis (PCA) revealed significant changes in PLFA pattern in planted and non-planted soils spiked with PYR. Total PLFAs in planted soils were all higher than those in non-planted soils. PLFA assemblages indicated that bacteria were the primary PYR degrading microorganisms, and that Gram-positive bacteria exhibited higher tolerance to PYR than Gram-negative bacteria did. ?? 2008 Higher Education Press and Springer-Verlag GmbH.

Spatial and seasonal variations in mercury methylation and microbial community structure in a historic mercury mining area, Yolo County, California

USGS Publications Warehouse

Holloway, J.M.; Goldhaber, M.B.; Scow, K.M.; Drenovsky, R.E.

2009-01-01

The relationships between soil parent lithology, nutrient concentrations, microbial biomass and community structure were evaluated in soils from a small watershed impacted by historic Hg mining. Upland and wetland soils, stream sediments and tailings were collected and analyzed for nutrients (DOC, SO4=, NO3-), Hg, MeHg, and phospholipid fatty acids (PLFA). Stream sediment was derived from serpentinite, siltstone, volcanic rocks and mineralized serpentine with cinnabar, metacinnabar and other Hg phases. Soils from different parent materials had distinct PLFA biomass and community structures that are related to nutrient concentrations and toxicity effects of trace metals including Hg. The formation of MeHg appears to be most strongly linked to soil moisture, which in turn has a correlative relationship with PLFA biomass in wetland soils. The greatest concentrations of MeHg (> 0.5??ng g- 1 MeHg) were measured in wetland soils and soil with a volcanic parent (9.5-37????g g- 1 Hg). Mercury methylation was associated with sulfate-reducing bacteria, including Desulfobacter sp. and Desulfovibrio sp., although these organisms are not exclusively responsible for Hg methylation. Statistical models of the data demonstrated that soil microbial communities varied more with soil type than with season.

Long-term impact of farm management and crops on soil microorganisms assessed by combined DGGE and PLFA analyses

PubMed Central

Stagnari, Fabio; Perpetuini, Giorgia; Tofalo, Rosanna; Campanelli, Gabriele; Leteo, Fabrizio; Della Vella, Umberto; Schirone, Maria; Suzzi, Giovanna; Pisante, Michele

2014-01-01

In the present study, long-term organic and conventional managements were compared at the experimental field of Monsampolo del Tronto (Marche region, Italy) with the aim of investigating soil chemical fertility and microbial community structure. A polyphasic approach, combining soil fertility indicators with microbiological analyses (plate counts, PCR-denaturing gradient gel electrophoresis [DGGE] and phospholipid fatty acid analysis [PLFA]) was applied. Organic matter, N as well as some important macro and micronutrients (K, P, Mg, Mn, Cu, and Zn) for crop growth, were more available under organic management. Bacterial counts were higher in organic management. A significant influence of management system and management x crop interaction was observed for total mesophilic bacteria, nitrogen fixing bacteria and actinobacteria. Interestingly, cultivable fungi were not detected in all analyzed samples. PLFA biomass was higher in the organic and Gram positive bacteria dominated the microbial community in both systems. Even if fungal biomass was higher in organic management, fungal PCR-DGGE fingerprinting revealed that the two systems were very similar in terms of fungal species suggesting that 10 years were not enough to establish a new dynamic equilibrium among ecosystem components. A better knowledge of soil biota and in particular of fungal community structure will be useful for the development of sustainable management strategies. PMID:25540640

Does acute lead (Pb) contamination influence membrane fatty acid composition and freeze tolerance in intertidal blue mussels in arctic Greenland?

PubMed

Thyrring, Jakob; Juhl, Bodil Klein; Holmstrup, Martin; Blicher, Martin E; Sejr, Mikael K

2015-11-01

In their natural habitats, organisms are exposed to multiple stressors. Heavy metal contamination stresses the cell membrane due to increased peroxidation of lipids. Likewise, sub-zero air temperatures potentially reduce membrane functionality in ectothermal animals. We tested if acute lead (Pb) exposure for 7 days would influence survival in intertidal blue mussels (Mytilus edulis) after exposure to realistic sub-zero air temperatures. A full factorial experiment with five tissue Pb concentrations between 0 and 3500 μg Pb/g and six sub-zero temperatures from 0 to -17 °C were used to test the hypothesis that sub-lethal effects of Pb may increase the lethality caused by freezing in blue mussels exposed to temperatures simulating Greenland winter conditions. We found a significant effect of temperature on mortality. However, the short-term exposure to Pb did not result in any effects of Pb, nor did we find interactions between Pb and temperature. We analysed the relative abundance of major phospholipid fatty acids (PLFAs) in the gill tissue, but we found no significant effect of Pb tissue concentration on PLFA composition. Results suggest that Pb accumulation has limited effects on freeze tolerance and does not induce membrane damage in terms of persistent lipid peroxidation.

Microbial utilization of litter carbon under the effect of extreme weather events

NASA Astrophysics Data System (ADS)

Heinrich, Steffen; Kuzyakov, Yakov; Glaser, Bruno

2015-04-01

Climate change is expected to not only lead to an increase of average annual temperature but also to increase the frequency of extreme meteorological events. For example, extreme summer-droughts followed by heavy rainfall events are likely to increase. This may change SOM quality, composition, microbial community functioning and thus C turnover in temperate forest ecosystems. Therefore, we performed a tracer experiment in the "Fichtelgebirge" (Northern Bavaria) to verify the influence of strong drying followed by intensive rewetting on the microbial community structure and decomposition of litter-derived 13C by individual microbial groups. In 2010, sheltered plots with artificially simulated drought, those with additional irrigation and control sites under natural conditions were established at a Norway spruce forest. At each plot, we added 13C enriched spruce litter to simulate annual litter fall. Thereafter, we assessed the effect of extreme weather events on microbial community structure by phospholipid fatty acid (PLFA) analysis. In addition, we analyzed the 13C incorporation into bulk soil, microbial biomass and PLFA of the organic horizon and the mineral soil up to 10 cm. Additionally respired CO2 was quantified by closed chambers. Drought reduced the microbial biomass only in the organic horizon, while in the mineral soil the microbial abundance did not decrease compared to the control and irrigated plots. The decrease in microbial biomass in the organic horizon of the drought plots resulted also in a strongly reduced incorporation of litter derived C: Incorporation of litter 13C was a magnitude of three lower in the drought plots compared to the control and irrigation plots. Furthermore, after the drought period of 90 days the proportion of 13C in CO2 from soil respiration was reduced by about 95% on the drought plots compared to the control and irrigated plots. This is in agreement with the reduced degradation of litter derived C and thus a reduced C turnover under dry conditions. PLFA analysis showed high amounts of gram positive and gram negative bacterial as well as fungal fatty acids, whereas actinomycets and protozoa represented minor groups. An increased ratio of the cy-PLFA to (16:1w7c+18:1w7c) on the drought plots of the organic layer suggest that bacteria suffered from water stress. In comparison to other microbial groups only the fungi were not depleted by drought showing the advantage of hyphae in resisting unfavourable environmental conditions compared to the single cells organisms. Both, in the organic horizon and the mineral soil, most 13C was incorporated into the gram negative bacteria and into fungi, whereas actinomycetes and protozoa showed the lowest incorporation. This tendency is even enhanced for the drought plots. Gram positive bacteria showed a low incorporation of litter derived C despite their high abundance, which reflects their general preference for old SOM-derived C sources. Combining 13C-labeling and 13C partitioning in microbial and SOM pools provides a powerful method combination to understand the mechanisms of SOM turnover especially those which are microbially controlled. This will fundamentally improve our understanding of C pool dynamics under changing environmental conditions like extreme whether events.

Changes in microbial community structure following herbicide (glyphosate) additions to forest soils

Treesearch

Alice W. Ratcliff; Matt D. Busse; Carol J. Shestak

2006-01-01

Glyphosate applied at the recommended field rate to a clay loam and a sandy loam forest soil resulted in few changes in microbial community structure. Total and culturable bacteria, fungal hyphal length, bacterial:fungal biomass, carbon utilization profiles (BIOLOG), and bacterial and fungal phospholipid fatty acids (PLFA) were unaffected 1, 3, 7, or 30 days...

Response of soil organic carbon fractions, microbial community composition and carbon mineralization to high-input fertilizer practices under an intensive agricultural system

PubMed Central

Wu, Xueping; Gebremikael, Mesfin Tsegaye; Wu, Huijun; Cai, Dianxiong; Wang, Bisheng; Li, Baoguo; Zhang, Jiancheng; Li, Yongshan; Xi, Jilong

2018-01-01

Microbial mechanisms associated with soil organic carbon (SOC) decomposition are poorly understood. We aim to determine the effects of inorganic and organic fertilizers on soil labile carbon (C) pools, microbial community structure and C mineralization rate under an intensive wheat-maize double cropping system in Northern China. Soil samples in 0–10 cm layer were collected from a nine-year field trial involved four treatments: no fertilizer, CK; nitrogen (N) and phosphorus (P) fertilizers, NP; maize straw combined with NP fertilizers, NPS; and manure plus straw and NP fertilizers, NPSM. Soil samples were analyzed to determine labile C pools (including dissolved organic C, DOC; light free organic C, LFOC; and microbial biomass C, MBC), microbial community composition (using phospholipid fatty acid (PLFA) profiles) and SOC mineralization rate (from a 124-day incubation experiment). This study demonstrated that the application of chemical fertilizers (NP) alone did not alter labile C fractions, soil microbial communities and SOC mineralization rate from those observed in the CK treatment. Whereas the use of straw in conjunction with chemical fertilizers (NPS) became an additional labile substrate supply that decreased C limitation, stimulated growth of all PLFA-related microbial communities, and resulted in 53% higher cumulative mineralization of C compared to that of CK. The SOC and its labile fractions explained 78.7% of the variance of microbial community structure. Further addition of manure on the top of straw in the NPSM treatment did not significantly increase microbial community abundances, but it did alter microbial community structure by increasing G+/G- ratio compared to that of NPS. The cumulative mineralization of C was 85% higher under NPSM fertilization compared to that of CK. Particularly, the NPSM treatment increased the mineralization rate of the resistant pool. This has to be carefully taken into account when setting realistic and effective goals for long-term soil C stabilization. PMID:29668702

Response of soil organic carbon fractions, microbial community composition and carbon mineralization to high-input fertilizer practices under an intensive agricultural system.

PubMed

Li, Jing; Wu, Xueping; Gebremikael, Mesfin Tsegaye; Wu, Huijun; Cai, Dianxiong; Wang, Bisheng; Li, Baoguo; Zhang, Jiancheng; Li, Yongshan; Xi, Jilong

2018-01-01

Microbial mechanisms associated with soil organic carbon (SOC) decomposition are poorly understood. We aim to determine the effects of inorganic and organic fertilizers on soil labile carbon (C) pools, microbial community structure and C mineralization rate under an intensive wheat-maize double cropping system in Northern China. Soil samples in 0-10 cm layer were collected from a nine-year field trial involved four treatments: no fertilizer, CK; nitrogen (N) and phosphorus (P) fertilizers, NP; maize straw combined with NP fertilizers, NPS; and manure plus straw and NP fertilizers, NPSM. Soil samples were analyzed to determine labile C pools (including dissolved organic C, DOC; light free organic C, LFOC; and microbial biomass C, MBC), microbial community composition (using phospholipid fatty acid (PLFA) profiles) and SOC mineralization rate (from a 124-day incubation experiment). This study demonstrated that the application of chemical fertilizers (NP) alone did not alter labile C fractions, soil microbial communities and SOC mineralization rate from those observed in the CK treatment. Whereas the use of straw in conjunction with chemical fertilizers (NPS) became an additional labile substrate supply that decreased C limitation, stimulated growth of all PLFA-related microbial communities, and resulted in 53% higher cumulative mineralization of C compared to that of CK. The SOC and its labile fractions explained 78.7% of the variance of microbial community structure. Further addition of manure on the top of straw in the NPSM treatment did not significantly increase microbial community abundances, but it did alter microbial community structure by increasing G+/G- ratio compared to that of NPS. The cumulative mineralization of C was 85% higher under NPSM fertilization compared to that of CK. Particularly, the NPSM treatment increased the mineralization rate of the resistant pool. This has to be carefully taken into account when setting realistic and effective goals for long-term soil C stabilization.

Detection and cultivation of indigenous microorganisms in Mesozoic claystone core samples from the Opalinus Clay Formation (Mont Terri Rock Laboratory)

NASA Astrophysics Data System (ADS)

Mauclaire, L.; McKenzie, J. A.; Schwyn, B.; Bossart, P.

Although microorganisms have been isolated from various deep-subsurface environments, the persistence of microbial activity in claystones buried to great depths and on geological time scales has been poorly studied. The presence of in-situ microbial life in the Opalinus Clay Formation (Mesozoic claystone, 170 million years old) at the Mont Terri Rock Laboratory, Canton Jura, Switzerland was investigated. Opalinus Clay is a host rock candidate for a radioactive waste repository. Particle tracer tests demonstrated the uncontaminated nature of the cored samples, showing their suitability for microbiological investigations. To determine whether microorganisms are a consistent and characteristic component of the Opalinus Clay Formation, two approaches were used: (i) the cultivation of indigenous micoorganisms focusing mainly on the cultivation of sulfate-reducing bacteria, and (ii) the direct detection of molecular biomarkers of bacteria. The goal of the first set of experiments was to assess the presence of cultivable microorganisms within the Opalinus Clay Formation. After few months of incubation, the number of cell ranged from 0.1 to 2 × 10 3 cells ml -1 media. The microorganisms were actively growing as confirmed by the observation of dividing cells, and detection of traces of sulfide. To avoid cultivation bias, quantification of molecular biomarkers (phospholipid fatty acids) was used to assess the presence of autochthonous microorganisms. These molecules are good indicators of the presence of living cells. The Opalinus Clay contained on average 64 ng of PLFA g -1 dry claystone. The detected microbial community comprises mainly Gram-negative anaerobic bacteria as indicated by the ratio of iso/anteiso phospholipids (about 2) and the detection of large amount of β-hydroxy substituted fatty acids. The PLFA composition reveals the presence of specific functional groups of microorganisms in particular sulfate-reducing bacteria ( Desulfovibrio, Desulfobulbus, and Desulfobacter). This study demonstrates that microorganisms are a characteristic component of the unperturbed Opalinus Clay Formation.

Mechanisms Controlling the Plant Diversity Effect on Soil Microbial Community Composition and Soil Microbial Diversity

NASA Astrophysics Data System (ADS)

Mellado Vázquez, P. G.; Lange, M.; Griffiths, R.; Malik, A.; Ravenek, J.; Strecker, T.; Eisenhauer, N.; Gleixner, G.

2015-12-01

Soil microorganisms are the main drivers of soil organic matter cycling. Organic matter input by living plants is the major energy and matter source for soil microorganisms, higher organic matter inputs are found in highly diverse plant communities. It is therefore relevant to understand how plant diversity alters the soil microbial community and soil organic matter. In a general sense, microbial biomass and microbial diversity increase with increasing plant diversity, however the mechanisms driving these interactions are not fully explored. Working with soils from a long-term biodiversity experiment (The Jena Experiment), we investigated how changes in the soil microbial dynamics related to plant diversity were explained by biotic and abiotic factors. Microbial biomass quantification and differentiation of bacterial and fungal groups was done by phospholipid fatty acid (PLFA) analysis; terminal-restriction fragment length polymorphism was used to determine the bacterial diversity. Gram negative (G-) bacteria predominated in high plant diversity; Gram positive (G+) bacteria were more abundant in low plant diversity and saprotrophic fungi were independent from plant diversity. The separation between G- and G+ bacteria in relation to plant diversity was governed by a difference in carbon-input related factors (e.g. root biomass and soil moisture) between plant diversity levels. Moreover, the bacterial diversity increased with plant diversity and the evenness of the PLFA markers decreased. Our results showed that higher plant diversity favors carbon-input related factors and this in turn favors the development of microbial communities specialized in utilizing new carbon inputs (i.e. G- bacteria), which are contributing to the export of new C from plants to soils.

Linking Toluene Degradation with Specific Microbial Populations in Soil

PubMed Central

Hanson, Jessica R.; Macalady, Jennifer L.; Harris, David; Scow, Kate M.

1999-01-01

Phospholipid fatty acid (PLFA) analysis of a soil microbial community was coupled with 13C isotope tracer analysis to measure the community’s response to addition of 35 μg of [13C]toluene ml of soil solution−1. After 119 h of incubation with toluene, 96% of the incorporated 13C was detected in only 16 of the total 59 PLFAs (27%) extracted from the soil. Of the total 13C-enriched PLFAs, 85% were identical to the PLFAs contained in a toluene-metabolizing bacterium isolated from the same soil. In contrast, the majority of the soil PLFAs (91%) became labeled when the same soil was incubated with [13C]glucose. Our study showed that coupling 13C tracer analysis with PLFA analysis is an effective technique for distinguishing a specific microbial population involved in metabolism of a labeled substrate in complex environments such as soil. PMID:10583996

Dose-dependent consumption of farmed Atlantic salmon (Salmo salar) increases plasma phospholipid n-3 fatty acids differentially

PubMed Central

Raatz, Susan K.; Rosenberger, Thad A.; Johnson, LuAnn K.; Wolters, William W.; Burr, Gary S; Picklo, Matthew J.

2013-01-01

Enhanced omega-3 fatty acid (n-3) intake benefits cardiovascular disease (CVD) risk reduction. Increasing consumption at a population level may be better addressed by diet than through supplementation. However, limited data are available on the effect of the dose response to fish intake on plasma levels of n-3 fatty acids. To compare the effects of different doses of farmed Atlantic salmon on plasma phospholipid fatty acid (PLFA) proportions and CVD risk biomarkers (glucose, insulin, HOMAIR, hsCRP, and IL-6) in healthy subjects we performed a randomized 3-period cross-over designed trial (4 wk treatment, 4-8 wk washout) to compare the effects of twice/wk consumption of farmed Atlantic salmon at doses of 90, 180, and 270 g in 19 apparently healthy men and women with a mean age of aged 40-65 years and a BMI between 25-34.9 kg/m2. All study visits were conducted at the USDA, ARS Grand Forks Human Nutrition Research Center. EPA and total n-3 were increased (p<0.05) by all treatments in a dose response manner, with total n-3 of 8.03 ± 0.26 and 9.21 ± 0.26 % for 180 and 270 g doses, respectively. Linoleic acid did not change in response to treatment while arachidonic acid (P<0.05) and total omega-6 fatty acids (n-6) decreased dose dependently (<0.0001). The addition of farmed Atlantic salmon to the diet twice/wk for 4 wk at portions of 180g and 270g modifies PLFA proportions of n-3 and n-6 in a level associated with decreased risk for CVD. PMID:23351633

Microbial population dynamics in the sediments of a eutrophic lake (Aydat, France) and characterization of some heterotrophic bacterial isolates.

PubMed

Mallet, C; Basset, M; Fonty, G; Desvilettes, C; Bourdier, G; Debroas, D

2004-07-01

The bacterial populations of anoxic sediments in a eutrophic lake (Aydat, Puy-de-Dôme-France) were studied by phospholipid fatty acid analysis (PLFA) and also by culturing heterotrophic bacteria under strictly anaerobic conditions. The mean PLFA concentrations of prokaryotes and microeukaryotes were 5.7 +/- 2.9 mgC g(-1) DS and 9.6 +/- 6.7 mgC g(-1) DS, respectively. The analysis of bacterial PLFA markers was used to determine the dynamics of the Gram-positive and Gram-negative species of anaerobic bacteria, Clostridiae, and sulfate-reducing bacteria. Throughout the sampling period the concentrations of i15:0 (from 20 nmol g(-1) DS to 130 nmol g(-1) DS), markers of Gram-positive bacteria, were higher than those for Gram-negative bacteria. The dynamics of Clostridiae (Cy15:0) paralleled those of sulfate-reducing bacteria that were marked by i17:1omega7. Partial 16S rDNA sequencing and the physiological study of the various fermenting strains, whose abundance in the superficial sediment layer was 1.1 +/- 0.4 x 10(6) cells mL(-1), showed that all the isolates belonged to the Clostridiae and related taxa ( Lactosphaera pasteurii, Clostridium vincentii, C. butyricum, C. algidixylanolyticum, C. puniceum, C. lituseburense, and C. gasigenes). All the isolates were capable of metabolizing a wide range of organic substrates.

Changes in relative and absolute concentrations of plasma phospholipid fatty acids observed in a randomized trial of Omega-3 fatty acids supplementation in Uganda

PubMed Central

Song, Xiaoling; Diep, Pho; Schenk, Jeannette M; Casper, Corey; Orem, Jackson; Makhoul, Zeina; Lampe, Johanna W; Neuhouser, Marian L.

2016-01-01

Expressing circulating phospholipid fatty acids (PLFAs) in relative concentrations has some limitations: the total of all fatty acids are summed to 100%; therefore, the values of individual fatty acid are not independent. In this study we examined if both relative and absolute metrics could effectively measure changes in circulating PLFA concentrations in an intervention trial. 66 HIV and HHV8 infected patients in Uganda were randomized to take 3g/d of either long-chain omega-3 fatty acids (1,856 mg EPA and 1,232 mg DHA) or high—oleic safflower oil in a 12-week double-blind trial. Plasma samples were collected at baseline and end of trial. Relative weight percentage and absolute concentrations of 41 plasma PLFAs were measured using gas chromatography. Total cholesterol was also measured. Intervention-effect changes in concentrations were calculated as differences between end of 12-week trial and baseline. Pearson correlations of relative and absolute concentration changes in individual PLFAs were high (>0.6) for 37 of the 41 PLFAs analyzed. In the intervention arm, 17 PLFAs changed significantly in relative concentration and 16 in absolute concentration, 15 of which were identical. Absolute concentration of total PLFAs decreased 95.1 mg/L (95% CI: 26.0, 164.2; P = 0.0085), but total cholesterol did not change significantly in the intervention arm. No significant change was observed in any of the measurements in the placebo arm. Both relative weight percentage and absolute concentrations could effectively measure changes in plasma PLFA concentrations. EPA and DHA supplementation changes the concentrations of multiple plasma PLFAs besides EPA and DHA. PMID:27926458

Multiple indices of soil nitrogen status and temperature regulate microbial C allocation to CO2, substrate choices, and contributions to SOM

NASA Astrophysics Data System (ADS)

Billings, S. A.; Ziegler, S. E.

2012-12-01

The response of microbial resource demand to many environmental variables, including temperature and natural organic and inorganic N variability, remains poorly understood. Furthermore, we do not understand how these variables can influence CO2 release vs. C retention in cell walls, which as microbial necromass can generate long-lived soil organic matter (SOM). We explore microbial resource demand and C retention vs. release in one temperate forest and two boreal forests along a climate gradient. We characterized SOM C:N and inorganic N, extracellular enzyme activity (E), and phospholipid fatty acid (PLFA) concentration and δ13C. Experimental warming permitted us to assess how interactions between soil N status and warming influence resource demand and C flows through microbes in the two boreal soils. For all soils, we used δ13C of respired CO2 and δ13CPLFA to generate indices of C allocation to biomass vs. to respiratory costs (Δ), useful for cross-site comparisons. Decreasing values of Δ indicate a greater proportion of 13C-enriched C allocated to respiration relative to PLFA-C; changes in Δ with warming or N status thus imply that these variables can influence the physiological mechanisms determining the fate of microbial C after it is imported into the cell. We thus were able to assess the influence of soil N status and warming on substrate decay via E, the fate of microbial C from diverse substrates via Δ, and one index of microbial composition relevant to SOM formation [PLFA]. In all soils, E often varied with N status in ways predicted by stoichiometric theory. For example, the ratio of exo-enzymes associated with labile C decay to those linked to organic N decay (EC:N) increased with inorganic N, and EC:N declined as substrate C:N increased. In contrast to measures of decay, all soils exhibited distinct responses of microbial composition and C allocation to N status and warming. In the temperate forest soils, Gram+ bacteria responded positively to organic N availability and Gram- bacteria to inorganic N, while fungi responded positively to declines in both measures of soil N status. In the more northern boreal soils, actinomycete [PLFA] increased with inorganic N, while that of more southern boreal soils increased with substrate C:N; in both boreal soils, Gram+ bacteria increased with temperature. Given that cell walls of these microbes exhibit distinct propensities for forming long-lived SOM, our work illustrates how similar variation in N status and temperature can drive divergent patterns of biomass relevant to SOM formation. Sensitivity of patterns of C allocation to these variables also contrasted between these soils. In the temperate soils, Δ did not vary with soil N status nor with E, implying that microbes' C allocation patterns were not driven N status or by the C's organic precursor. In both boreal soils, Δ declined with warming, and as EC or EC:N increased. Though N status of the boreal soils drove resource demand similarly as in the temperate forest, the fate of boreal microbial C varied with N status and temperature. Because microbial C substrate use varied with warming in the boreal soils, Δ highlights how the fate of microbial C may vary with the identity of its organic precursor, which in turn is influenced by environmental conditions like temperature and soil N status.

Linking of Microorganisms to Phenanthrene Metabolism in Soil by Analysis of 13C-Labeled Cell Lipids

PubMed Central

Johnsen, Anders R.; Winding, Anne; Karlson, Ulrich; Roslev, Peter

2002-01-01

Phenanthrene-metabolizing soil microbial communities were characterized by examining mineralization of [14C]phenanthrene, by most-probable-number (MPN) counting, by 16S-23S spacer DNA analysis of the numerically dominant, culturable phenanthrene-degrading isolates, and by examining incorporation of [13C]phenanthrene-derived carbon into sterols and polar lipid fatty acids (PLFAs). An unpolluted agricultural soil, a roadside soil diffusely polluted with polycyclic aromatic hydrocarbons (PAHs), and two highly PAH-polluted soils from industrial sites were analyzed. Microbial phenanthrene degraders were not detected by MPN counting in the agricultural soil and the roadside soil. In the industrial soils, phenanthrene degraders constituted 0.04 and 3.6% of the total number of CFU. 16S-23S spacer DNA analysis followed by partial 16S DNA sequencing of representative isolates from one of the industrial soils showed that one-half of the isolates belonged to the genus Sphingomonas and the other half were closely related to an unclassified beta-proteobacterium. The 13C-PLFA profiles of the two industrial soils were relatively similar and resembled the profiles of phenanthrene-degrading Sphingomonas reference strains and unclassified beta-proteobacterium isolates but did not match the profiles of Pseudomonas, Mycobacterium, or Nocardia reference strains. The 13C-PLFA profiles of phenanthrene degraders in the agricultural soil and the roadside soil were different from each other and different from the profiles of the highly polluted industrial soils. Only in the roadside soil were 10me/12me18:0 PLFAs enriched in 13C, suggesting that actinomycetes metabolized phenanthrene in this soil. The 13C-PLFA profiles of the unpolluted agricultural soil did not resemble the profiles of any of the reference strains. In all of the soils investigated, no excess 13C was recovered in the 18:2ω6,9 PLFA, suggesting that fungi did not contribute significantly to assimilation of [13C]phenanthrene. PMID:12450834

Field-Scale Stable-Isotope Probing of Active Methanotrophs in a Landfill-Cover Soil

NASA Astrophysics Data System (ADS)

Schroth, M. H.; Henneberger, R.; Chiri, E.

2012-12-01

The greenhouse gas methane (CH4) is an important contributor to global climate change. While its atmospheric concentration is increasing, a large portion of produced CH4 never reaches the atmosphere, but is consumed by aerobic methane-oxidizing bacteria (MOB). The latter are ubiquitous in soils and utilize CH4 as sole source of energy and carbon. Among other methods, MOB may be differentiated based on characteristic phospholipid fatty acids (PLFA). Stable-isotope probing (SIP) on PLFA has been widely applied to identify active members of MOB communities in laboratory incubation studies, but results are often difficult to extrapolate to the field. Thus, novel field-scale approaches are needed to link activity and identity of MOB in their natural environment. We present results of field experiments in which we combined PLFA-SIP with gas push-pull tests (GPPTs) to label active MOB at the field-scale while simultaneously quantifying CH4 oxidation activity. During a SIP-GPPT, a mixture of reactive (here 13CH4, O2) and non-reactive tracer gases (e.g., Ar, Ne, He) is injected into the soil at a location of interest. Thereafter, gas flow is reversed and the gas mixture diluted with soil air is extracted from the same location and sampled periodically. Rate constants for CH4 oxidation can be calculated by analyzing breakthrough curves of 13CH4 and a suitable non-reactive tracer gas. SIP-GPPTs were performed in a landfill-cover soil, and feasibility of this novel approach was tested at several locations along a gradient of MOB activity and soil temperature. Soil samples were collected before and after SIP-GPPTs, total PLFA were extracted, and incorporation of 13C in the polar lipid fraction was analyzed. Potential CH4 oxidation rates derived from SIP-GPPTs were similar to those derived from regular GPPTs (using unlabeled CH4) performed at the same locations prior to SIP-GPPTs, indicating that application of 13CH4 did not adversely affect bacterial CH4 oxidation rates. Rates calculated for different locations ranged from 0.2 to 52.8 mmol CH4 (L soil air)-1 d-1. PLFA analyses showed high levels of 13C incorporation into different 14C and 16C fatty acids (FA), typically found in Type I MOB, and 18C FAs, typical for Type II MOB. The amount of 13C incorporated into biomass clearly increased with increasing activity, and δ13C values of >1500 ‰ were observed for selected FAs at high-activity locations. In addition, the range of labeled FAs also changed with activity, and no Type II MOB specific FAs were labeled at the low-activity location. The novel SIP-GPPT approach was shown to be a valuable field-scale method to detect and identify active MOB over a wide range of activities.

Stabilization of glucose-C in microbial cell membranes (PLFA) and cell walls (amino sugars) evaluated by 13C-labelling in a field experiment

NASA Astrophysics Data System (ADS)

Gunina, Anna; Kuzyakov, Yakov; Glaser, Bruno

2015-04-01

Microorganisms control carbon (C) cycle and strongly contribute to formation of soil organic matter. Strong differences in the turnover of microbial groups and cellular compounds complicate the assessment of their contribution to microbial food webs and C sequestration in soil in situ. The uptake and incorporation of 13C labeled glucose by microbial groups were traced during 50 days after the labeling under field conditions. 13C was analysed: i) in the cytosolic pool by chloroform fumigation extraction, ii) in cell membranes by phospholipid fatty acids (PLFA), iii) in cell walls by amino sugars, and iv) remaining in bulk soil. This allowed tracing C in microbial groups as well as cellular compounds. Mean residence times (MRT) of C in PLFA and the cytosol were 47 and 150 days, respectively. Such long cytosol MRT depends on its heterogeneous composition, which includes high and low molecular weight organics. Amino sugars were mainly originated from microbial residues and thus, observation periods higher than 1 year are required for estimation of their MRT. Relative 13C incorporation (13C portion in total pool C) was the highest for PLFAs (~1.5% at day 3), whereas 13C content of the cytosol and amino sugars was one and two orders of magnitude less, respectively. Relative 13C incorporation into amino sugars of living microorganisms showed only 0.57% on day 3. Therefore, the turnover of cell membrane components is two times faster than that of cell walls, even in living microorganisms. Both PLFAs and amino sugars showed that glucose C was preferentially used by bacteria. 13C incorporation into bacterial cell walls and membranes decreased with time, but increased or remained constant for fungi, reflecting faster turnover of bacteria than fungi. Consequently, bacteria contribute more to the decomposition of low molecular weight organics, whereas fungi consume bacterial products or necromass and contribute more to long-term C stabilisation. Thus, tracing of 13C in cellular compounds with contrasting turnover provides key information to C fluxes through the soil microbial food-web and elucidates the role of distinct groups as well as individual cellular compartments in SOM formation and C sequestration.

Microbial ecology of two hot springs of Sikkim: Predominate population and geochemistry.

PubMed

Najar, Ishfaq Nabi; Sherpa, Mingma Thundu; Das, Sayak; Das, Saurav; Thakur, Nagendra

2018-10-01

Northeastern regions of India are known for their floral and faunal biodiversity. Especially the state of Sikkim lies in the eastern Himalayan ecological hotspot region. The state harbors many sulfur rich hot springs which have therapeutic and spiritual values. However, these hot springs are yet to be explored for their microbial ecology. The development of neo generation techniques such as metagenomics has provided an opportunity for inclusive study of microbial community of different environment. The present study describes the microbial diversity in two hot springs of Sikkim that is Polok and Borong with the assist of culture dependent and culture independent approaches. The culture independent techniques used in this study were next generation sequencing (NGS) and Phospholipid Fatty Acid Analysis (PLFA). Having relatively distinct geochemistry both the hot springs are thermophilic environments with the temperature range of 50-77 °C and pH range of 5-8. Metagenomic data revealed the dominance of bacteria over archaea. The most abundant phyla were Proteobacteria and Bacteroidetes although other phyla were also present such as Acidobacteria, Nitrospirae, Firmicutes, Proteobacteria, Parcubacteria and Spirochaetes. The PLFA studies have shown the abundance of Gram Positive bacteria followed by Gram negative bacteria. The culture dependent technique was correlative with PLFA studies. Most abundant bacteria as isolated and identified were Gram-positive genus Geobacillus and Anoxybacillus. The genus Geobacillus has been reported for the first time in North-Eastern states of India. The Geobacillus species obtained from the concerned hot springs were Geobacillus toebii, Geobacillus lituanicus, Geobacillus Kaustophillus and the Anoxybacillus species includes Anoxybacillus gonensis and Anoxybacillus Caldiproteolyticus. The distribution of major genera and their statistical correlation analyses with the geochemistry of the springs predicted that the temperature, pH, alkalinity, Ca 2+ , Mg 2+ , Cl 2+ , and sulfur were main environmental variables influencing the microbial community composition and diversity. Also the piper diagram suggested that the water of both the hot springs are Ca-HCO 3- type and can be predicted as shallow fresh ground waters. This study has provided an insight into the ecological interaction of the diverse microbial communities and associated physicochemical parameters, which will help in determining the future studies on different biogeochemical pathways in these hot springs. Copyright © 2018. Published by Elsevier B.V.

Microbial biomass, community structure and metal tolerance of a naturally Pb-enriched forest soil.

PubMed

Bååth, E; Díaz-Raviña, M; Bakken, L R

2005-11-01

The effect of long-term elevated soil Pb levels on soil microbiota was studied at a forest site in Norway, where the soil has been severely contaminated with Pb since the last period of glaciation (several thousand years). Up to 10% Pb (total amount, w/w) has been found in the top layer. The microbial community was drastically affected, as judged from changes in the phospholipid fatty acid (PLFA) pattern. Specific PLFAs that were high in Pb-enriched soil were branched (especially br17:0 and br18:0), whereas PLFAs common in eukaryotic organisms such as fungi (18:2omega6,9 and 20:4) were low compared with levels at adjacent, uncontaminated sites. Congruent changes in the PLFA pattern were found upon analyzing the culturable part of the bacterial community. The high Pb concentrations in the soil resulted in increased tolerance to Pb of the bacterial community, measured using both thymidine incorporation and plate counts. Furthermore, changes in tolerance were correlated to changes in the community structure. The bacterial community of the most contaminated soils showed higher specific activity (thymidine and leucine incorporation rates) and higher culturability than that of control soils. Fungal colony forming units (CFUs) were 10 times lower in the most Pb-enriched soils, the species composition was widely different from that in control soils, and the isolated fungi had high Pb tolerance. The most commonly isolated fungus in Pb-enriched soils was Tolypocladium inflatum. Comparison of isolates from Pb-enriched soil and isolates from unpolluted soils showed that T. inflatum was intrinsically Pb-tolerant, and that the prolonged conditions with high Pb had not selected for any increased tolerance.

Effects of soil depth and plant-soil interaction on microbial community in temperate grasslands of northern China.

PubMed

Yao, Xiaodong; Zhang, Naili; Zeng, Hui; Wang, Wei

2018-07-15

Although the patterns and drivers of soil microbial community composition are well studied, little is known about the effects of plant-soil interactions and soil depth on soil microbial distribution at a regional scale. We examined 195 soil samples from 13 sites along a climatic transect in the temperate grasslands of northern China to measure the composition of and factors influencing soil microbial communities within a 1-m soil profile. Soil microbial community composition was measured using phospholipid fatty acids (PLFA) analysis. Fungi predominated in topsoil (0-10 cm) and bacteria and actinomycetes in deep soils (40-100 cm), independent of steppe types. This variation was explained by contemporary environmental factors (including above- and below-ground plant biomass, soil physicochemical and climatic factors) >58% in the 0-40 cm of soil depth, but <45% in deep soils. Interestingly, when we considered the interactive effects between plant traits (above ground biomass and root biomass) and soil factors (pH, clay content, and soil total carbon, nitrogen, phosphorous), we observed a significant interaction effect occurring at depths of 10-20 cm soil layer, due to different internal and external factors of the plant-soil system along the soil profile. These results improve understanding of the drivers of soil microbial community composition at regional scales. Copyright © 2018 Elsevier B.V. All rights reserved.

Alteration of soil microbial communities and water quality in restored wetlands

USGS Publications Warehouse

Bossio, D.A.; Fleck, J.A.; Scow, K.M.; Fujii, R.

2006-01-01

Land usage is a strong determinant of soil microbial community composition and activity, which in turn determine organic matter decomposition rates and decomposition products in soils. Microbial communities in permanently flooded wetlands, such as those created by wetland restoration on Sacramento-San Joaquin Delta islands in California, function under restricted aeration conditions that result in increasing anaerobiosis with depth. It was hypothesized that the change from agricultural management to permanently flooded wetland would alter microbial community composition, increase the amount and reactivity of dissolved organic carbon (DOC) compounds in Delta waters; and have a predominant impact on microbial communities as compared with the effects of other environmental factors including soil type and agricultural management. Based on phospholipid fatty acid (PLFA) analysis, active microbial communities of the restored wetlands were changed significantly from those of the agricultural fields, and wetland microbial communities varied widely with soil depth. The relative abundance of monounsaturated fatty acids decreased with increasing soil depth in both wetland and agricultural profiles, whereas branched fatty acids were relatively more abundant at all soil depths in wetlands as compared to agricultural fields. Decomposition conditions were linked to DOC quantity and quality using fatty acid functional groups to conclude that restricted aeration conditions found in the wetlands were strongly related to production of reactive carbon compounds. But current vegetation may have had an equally important role in determining DOC quality in restored wetlands. In a larger scale analysis, that included data from wetland and agricultural sites on Delta islands and data from two previous studies from the Sacramento Valley, an aeration gradient was defined as the predominant determinant of active microbial communities across soil types and land usage. ?? 2005 Elsevier Ltd. All rights reserved.

Assessment of the spatial distribution of soil microbial communities in patchy arid and semi-arid landscapes of the Negev Desert using combined PLFA and DGGE analyses.

PubMed

Ben-David, Eric A; Zaady, Eli; Sher, Yoni; Nejidat, Ali

2011-06-01

Arid and semi-arid ecosystems are often characterized by vegetation patchiness and variable availability of resources. Phospholipid fatty acid (PLFA) and 16S rRNA gene fragment analyses were used to compare the bulk soil microbial community structure at patchy arid and semi-arid landscapes. Multivariate analyses of the PLFA data and the 16S rRNA gene fragments were in agreement with each other, suggesting that the differences between bulk soil microbial communities were primarily related to shrub vs intershrub patches, irrespective of climatic or site differences. This suggests that the mere presence of a living shrub is the dominant driving factor for the differential adaptation of the microbial communities. Lipid markers suggested as indicators of Gram-positive bacteria were higher in soils under the shrub canopies, while markers suggested as indicators of cyanobacteria and anaerobic bacteria were elevated in the intershrub soils. Secondary differences between soil microbial communities were associated with intershrub characteristics and to a lesser extent with the shrub species. This study provides an insight into the multifaceted nature of the factors that shape the microbial community structure in patchy desert landscapes. It further suggests that these drivers not only act in concert but also in a way that is dependent on the aridity level. © 2011 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

A Column Experiment To Determine Black Shale Degradation And Colonization By Means of δ13C and 14C Analysis Of Phospholipid Fatty Acids And DNA Extraction

NASA Astrophysics Data System (ADS)

Seifert, A.; Gleixner, G.

2008-12-01

We investigated the degradation of black shale organic matter by microbial communities. We inoculated two columns respectively, with the fungi Schizophyllum commune, the gram-positive bacterium Pseudomonas putida and the gram-negative bacteria Streptomyces griseus and Streptomyces chartreusis. These microorganisms are known to degrade a wide variety of organic macromolecules. Additionally, we had two sets of control columns. To one set the same nutrient solution was added as to the inoculated columns and to the other set only sterile deionised water was supplied. All columns contained 1.5 kg of freshly crushed not autoclaved black shale material with a particle size of 0.63-2 mm. The columns were incubated at 28° C and 60% humidity in the dark. The aim was to investigate, which microorganisms live on black shales and if these microorganisms are able to degrade ancient organic matter. We used compound specific stable isotope measurement techniques and compound specific 14C-dating methods. After 183 days PLFAs were extracted from the columns to investigate the microbial community, furthermore we extracted on one hand total-DNA of column material and on the other hand DNA from pure cultures isolates which grew on Kinks-agar B, Starch-casein-nitrate-agar (SCN) and on complete-yeast-medium-agar (CYM). According to the PLFA analysis bacteria dominated in the columns, whereas in pure cultures more fungi were isolated. A principal component analysis revealed differences between the columns in accordance with the inoculation, but it seems that the inoculated microorganisms were replaced by the natural population. For AMS measurements palmitic acid (C 16:0) was re-isolated from total-PLFA-extract with a preparative fraction collector (PFC). Preliminary results of the study revealed that microorganisms are able to degrade black shale material and that PLFA analysis are useful methods to be combined with analysis of stable isotope and 14C measurements to study microbial degradation processes.

Impact of natural organic matter properties on the kinetics of suspended ion exchange process.

PubMed

Bazri, Mohammad Mahdi; Mohseni, Madjid

2016-03-15

Removal kinetics of four standard organic matter isolates under the application of strongly basic ion exchange resins (IEX) in suspended mode was studied under commercial application conditions. Suwannee River natural organic matter (SRNOM), SR fulvic acid (SRFA), and Pony Lake fulvic acid (PLFA) were greatly removed (>90%) and highly preferred by IEX resins (α > 5, over Cl(-), and HCO3(-)) while SR humic acid (SRHA) was the least preferred organic structure among the four isolates studied (α ≈ 1). Moreover, the efficacy of removal for fulvic acids (i.e., SRFA, PLFA) was consistent over consecutive reuse of IEX resins (i.e., loading cycles) whereas it decreased for SRNOM and SRHA over the course of operation. The stoichiometric correlation between the chloride released from the resins as a result of organic molecules uptake indicated that ion exchange was the dominant mechanism. Results obtained indicated that molecular weight and charge density of isolates played a major role in the performance of ion exchange process for organic matter removal. Furthermore, various empirical and physical models were evaluated using the experimental data and pore diffusion was found to be the rate-liming step during the uptake of organic matters; hence, it was used as the appropriate model to predict the kinetics of removal. Consequently, free liquid diffusivities and effective pore diffusion coefficients of organic molecules were estimated and findings were in agreement with the literature data that were obtained from spectrophotometric methods. Copyright © 2015 Elsevier Ltd. All rights reserved.

Greenhouse gas emissions from a Cu-contaminated soil remediated by in situ stabilization and phytomanaged by a mixed stand of poplar, willows, and false indigo-bush.

PubMed

Šimek, M; Elhottová, D; Mench, M; Giagnoni, L; Nannipieri, P; Renella, G

2017-11-02

Phytomanagement of trace element-contaminated soils can reduce soil toxicity and restore soil ecological functions, including the soil gas exchange with the atmosphere. We studied the emission rate of the greenhouse gases (GHGs) CO 2 , CH 4 , and N 2 O; the potential CH 4 oxidation; denitrification enzyme activity (DEA), and glucose mineralization of a Cu-contaminated soil amended with dolomitic limestone and compost, alone or in combination, after a 2-year phytomanagement with a mixed stand of Populus nigra, Salix viminalis, S. caprea, and Amorpha fruticosa. Soil microbial biomass and microbial community composition after analysis of the phospholipid fatty acids (PLFA) profile were determined. Phytomanagement significantly reduced Cu availability and soil toxicity, increased soil microbial biomass and glucose mineralization capacity, changed the composition of soil microbial communities, and increased the CO 2 and N 2 O emission rates and DEA. Despite such increases, microbial communities were evolving toward less GHG emission per unit of microbial biomass than in untreated soils. Overall, the aided phytostabilization option would allow methanotrophic populations to establish in the remediated soils due to decreased soil toxicity and increased nutrient availability.

Effects of organic amendments and mulches on soil microbial communities in quarry restoration under semiarid climate

NASA Astrophysics Data System (ADS)

Luna Ramos, Lourdes; Pastorelli, Roberta; Miralles Mellado, Isabel; Fabiani, Arturo; Bastida López, Felipe; Hernández Fernández, María Teresa; García Izquierdo, Carlos; Solé Benet, Albert

2015-04-01

Mining activities generate loss of the quality of the environment and landscape specially in arid and semiarid Mediterranean regions. A precondition for ecosystem reclamation in such highly disturbed mining areas is the development of functional soils with appropriate levels of organic matter. In an experimental soil restoration in limestone quarries from Sierra de Gádor (Almería), SE Spain, 9 plots 15 x 5 m were prepared to test organic amendments (compost from solid urban residues-DOW-, sludge from urban water treatment-SS-, control-NA-) and different mulches (fine gravel-GM-, wood chips-WM-, control-NM-) with the aim to improve soil/substrate properties and to reduce evaporation and erosion. In each experimental plot, 75 native plants (Macrochloa tenacissima, Anthyllis terniflora and Anthyllis cytisoides) were planted. After 5 years from the start of the experiment, we evaluated how microbial community composition responded to the organic amendments and mulches. Microbial community composition of both bacteria and fungi was determined by phospholipid fatty acid (PLFA) and polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) fingerprinting. The results of the two-way ANOVA showed that PLFAs were significantly affected by organic amendments but not by the mulches or interaction of both factors. Experimental plots with DOW showed significantly higher level of fungal PLFAs than those with SS and NA, even higher than the reference undisturbed soil. However, any plot with organic amendments did not reach the content of bacterial PLFAs of the reference soils. The bacterial diversity (evaluated by diversity indices calculated from DGGE profiles) was greater in soil samples taken under NA and GM. Comparing these indices in fungal DGGE, we found greater values for soil samples taken under DOW and without mulches. Results from UPGMA analysis showed significant differences in the structure of soil bacterial communities from the different treatments respect to that of reference soil. Fungal communities could be divided into main groups according to the organic amendment. Within each group, GM amendment generated fungal community structures with lower similarities with respect to the other mulch treatments. In contrast to PLFA results, DGGE fingerprints revealed significant influence of the combination of organic amendments and mulches on diversity and composition of soil microbial communities.

Influences of space, soil, nematodes and plants on microbial community composition of chalk grassland soils.

PubMed

Yergeau, Etienne; Bezemer, T Martijn; Hedlund, Katarina; Mortimer, Simon R; Kowalchuk, George A; Van Der Putten, Wim H

2010-08-01

Microbial communities respond to a variety of environmental factors related to resources (e.g. plant and soil organic matter), habitat (e.g. soil characteristics) and predation (e.g. nematodes, protozoa and viruses). However, the relative contribution of these factors on microbial community composition is poorly understood. Here, we sampled soils from 30 chalk grassland fields located in three different chalk hill ridges of Southern England, using a spatially explicit sampling scheme. We assessed microbial communities via phospholipid fatty acid (PLFA) analyses and PCR-denaturing gradient gel electrophoresis (DGGE) and measured soil characteristics, as well as nematode and plant community composition. The relative influences of space, soil, vegetation and nematodes on soil microorganisms were contrasted using variation partitioning and path analysis. Results indicate that soil characteristics and plant community composition, representing habitat and resources, shape soil microbial community composition, whereas the influence of nematodes, a potential predation factor, appears to be relatively small. Spatial variation in microbial community structure was detected at broad (between fields) and fine (within fields) scales, suggesting that microbial communities exhibit biogeographic patterns at different scales. Although our analysis included several relevant explanatory data sets, a large part of the variation in microbial communities remained unexplained (up to 92% in some analyses). However, in several analyses, significant parts of the variation in microbial community structure could be explained. The results of this study contribute to our understanding of the relative importance of different environmental and spatial factors in driving the composition of soil-borne microbial communities. © 2009 Society for Applied Microbiology and Blackwell Publishing Ltd.

Relationship between carbon and nitrogen mineralization in a subtropical soil

NASA Astrophysics Data System (ADS)

Li, Qianru; Sun, Yue; Zhang, Xinyu; Xu, Xingliang; Kuzyakov, Yakov

2014-05-01

In most soils, more than 90% nitrogen is bonded with carbon in organic forms. This indicates that carbon mineralization should be closely coupled with nitrogen mineralization, showing a positive correlation between carbon and nitrogen mineralization. To test this hypothesis above, we conducted an incubation using a subtropical soil for 10 days at 15 °C and 25 °C. 13C-labeled glucose and 15N-labeled ammonium or nitrate was used to separate CO2 and mineral N released from mineralization of soil organic matter and added glucose or inorganic nitrogen. Phospholipid fatty acid (PLFA) and four exoenzymes (i.e. β-1,4- Glucosaminidase, chitinase, acid phosphatase, β-1,4-N- acetyl glucosamine glycosidase) were also analyzed to detect change in microbial activities during the incubation. Our results showed that CO2 release decreased with increasing nitrogen mineralization rates. Temperature did not change this relationship between carbon and nitrogen mineralization. Although some changes in PLFA and the four exoenzymes were observed, these changes did not contribute to changes in carbon and nitrogen mineralization. These findings indicates that carbon and nitrogen mineralization in soil are more complicated than as previously expected. Future investigation should focus on why carbon and nitrogen mineralization are coupled in a negative correlation not in a positive correlation in many soils for a better understanding of carbon and nitrogen transformation during their mineralization.

[Effects of Different Altitudes on Soil Microbial PLFA and Enzyme Activity in Two Kinds of Forests].

PubMed

Zeng, Qing-ping; He, Bing-hui; Mao, Qiao-zhi; Wu, Yao-peng; Huang, Qi; Li, Yuan

2015-12-01

The soil microbial community is an important part in soil ecosystem, and it is sensitive to the ecological environment. Phospholipid-derived fatty acids ( PLFA ) analysis was used to examine variations in soil microbial community diversity and its influencing factors. The results showed that: there existed 48 PLFAs that were significant in the soil samples from six altitudes. The PLFAs of six altitudes with the highest contents were i16:0, 10Me17:0, 10Me18:0 TBSA. The citrus forest exhibited richer soil PLFAs distribution both in type and amount than those in masson pine. The microbial activity and functional diversity of masson pine were increased with increasing altitudes, and citrus forest gradually decreased, the PLFA content of different microbial groups in each altitude were significantly different. The richness index, Shannon-Wiener index and Pielou evenness index of masson pine in low elevation were holistically higher than those in high elevation. However, the highest richness index of citrus forest was in low altitude, the highest Shannon-Wiener index and Pielou evenness index were in high altitude. The PLFAs content of different microbial groups were closely correlated to the soil enzyme activities and environmental factors. The PLFAs of bacteria, actinomycetes, G⁻ (Gram- positive), G⁺ (Gram-negative) were positively correlated with Ure(urease) , Ive(invertase) , CAT( catalase activity) and forest type, the PLFAs of fungi was significantly correlated with Ure, Ive, CAT, the PLFAs of bacteria, fungi, actinomycetes, G⁻ , G⁺ were significantly negatively or less correlated with elevation. Ure, Ive, CAT, forest type and elevation are the pivotal factors controlling the soil microbial biomass and activities.

Diversity and Characterization of Sulfate-Reducing Bacteria in Groundwater at a Uranium Mill Tailings Site

PubMed Central

Chang, Yun-Juan; Peacock, Aaron D.; Long, Philip E.; Stephen, John R.; McKinley, James P.; Macnaughton, Sarah J.; Hussain, A. K. M. Anwar; Saxton, Arnold M.; White, David C.

2001-01-01

Microbially mediated reduction and immobilization of U(VI) to U(IV) plays a role in both natural attenuation and accelerated bioremediation of uranium-contaminated sites. To realize bioremediation potential and accurately predict natural attenuation, it is important to first understand the microbial diversity of such sites. In this paper, the distribution of sulfate-reducing bacteria (SRB) in contaminated groundwater associated with a uranium mill tailings disposal site at Shiprock, N.Mex., was investigated. Two culture-independent analyses were employed: sequencing of clone libraries of PCR-amplified dissimilatory sulfite reductase (DSR) gene fragments and phospholipid fatty acid (PLFA) biomarker analysis. A remarkable diversity among the DSR sequences was revealed, including sequences from δ-Proteobacteria, gram-positive organisms, and the Nitrospira division. PLFA analysis detected at least 52 different mid-chain-branched saturate PLFA and included a high proportion of 10me16:0. Desulfotomaculum and Desulfotomaculum-like sequences were the most dominant DSR genes detected. Those belonging to SRB within δ-Proteobacteria were mainly recovered from low-uranium (≤302 ppb) samples. One Desulfotomaculum-like sequence cluster overwhelmingly dominated high-U (>1,500 ppb) sites. Logistic regression showed a significant influence of uranium concentration over the dominance of this cluster of sequences (P = 0.0001). This strong association indicates that Desulfotomaculum has remarkable tolerance and adaptation to high levels of uranium and suggests the organism's possible involvement in natural attenuation of uranium. The in situ activity level of Desulfotomaculum in uranium-contaminated environments and its comparison to the activities of other SRB and other functional groups should be an important area for future research. PMID:11425735

Cross-Site Soil Microbial Communities under Tillage Regimes: Fungistasis and Microbial Biomarkers

PubMed Central

Yrjälä, Kim; Alakukku, Laura; Palojärvi, Ansa

2012-01-01

The exploitation of soil ecosystem services by agricultural management strategies requires knowledge of microbial communities in different management regimes. Crop cover by no-till management protects the soil surface, reducing the risk of erosion and nutrient leaching, but might increase straw residue-borne and soilborne plant-pathogenic fungi. A cross-site study of soil microbial communities and Fusarium fungistasis was conducted on six long-term agricultural fields with no-till and moldboard-plowed treatments. Microbial communities were studied at the topsoil surface (0 to 5 cm) and bottom (10 to 20 cm) by general bacterial and actinobacterial terminal restriction fragment length polymorphism (T-RFLP) and phospholipid fatty acid (PLFA) analyses. Fusarium culmorum soil fungistasis describing soil receptivity to plant-pathogenic fungi was explored by using the surface layer method. Soil depth had a significant impact on general bacterial as well as actinobacterial communities and PLFA profiles in no-till treatment, with a clear spatial distinction of communities (P < 0.05), whereas the depth-related separation of microbial communities was not observed in plowed fields. The fungal biomass was higher in no-till surface soil than in plowed soil (P < 0.07). Soil total microbial biomass and fungal biomass correlated with fungistasis (P < 0.02 for the sum of PLFAs; P < 0.001 for PLFA 18:2ω6). Our cross-site study demonstrated that agricultural management strategies can have a major impact on soil microbial community structures, indicating that it is possible to influence the soil processes with management decisions. The interactions between plant-pathogenic fungi and soil microbial communities are multifaceted, and a high level of fungistasis could be linked to the high microbial biomass in soil but not to the specific management strategy. PMID:22983972

Crop residue management and fertilization effects on soil organic matter and associated biological properties.

PubMed

Zhao, Bingzi; Zhang, Jiabao; Yu, Yueyue; Karlen, Douglas L; Hao, Xiying

2016-09-01

Returning crop residue may result in nutrient reduction in soil in the first few years. A two-year field experiment was conducted to assess whether this negative effect is alleviated by improved crop residue management (CRM). Nine treatments (3 CRM and 3 N fertilizer rates) were used. The CRM treatments were (1) R0: 100 % of the N using mineral fertilizer with no crop residues return; (2) R: crop residue plus mineral fertilizer as for the R0; and (3) Rc: crop residue plus 83 % of the N using mineral and 17 % manure fertilizer. Each CRM received N fertilizer rates at 270, 360, and 450 kg N ha(-1) year(-1). At the end of the experiment, soil NO3-N was reduced by 33 % from the R relative to the R0 treatment, while the Rc treatment resulted in a 21 to 44 % increase in occluded particulate organic C and N, and 80 °C extracted dissolved organic N, 19 to 32 % increase in microbial biomass C and protease activity, and higher monounsaturated phospholipid fatty acid (PLFA):saturated PLFA ratio from stimulating growth of indigenous bacteria when compared with the R treatment. Principal component analysis showed that the Biolog and PLFA profiles in the three CRM treatments were different from each other. Overall, these properties were not influenced by the used N fertilizer rates. Our results indicated that application of 17 % of the total N using manure in a field with crop residues return was effective for improving potential plant N availability and labile soil organic matter, primarily due to a shift in the dominant microorganisms.

Sulfur Biogeochemistry of an Oil Sands Composite Tailings Deposit

PubMed Central

Warren, Lesley A.; Kendra, Kathryn E.; Brady, Allyson L.; Slater, Greg F.

2016-01-01

Composite tailings (CT), an engineered, alkaline, saline mixture of oil sands tailings (FFT), processed sand and gypsum (CaSO4; 1 kg CaSO4 per m3 FFT) are used as a dry reclamation strategy in the Alberta Oil Sands Region (AOSR). It is estimated that 9.6 × 108 m3 of CT are either in, or awaiting emplacement in surface pits within the AOSR, highlighting their potential global importance in sulfur cycling. Here, in the first CT sulfur biogeochemistry investigation, integrated geochemical, pyrosequencing and lipid analyses identified high aqueous concentrations of ∑H2S (>300 μM) and highly altered sulfur compounds composition; low cell biomass (3.3 × 106– 6.0 × 106 cells g−1) and modest bacterial diversity (H' range between 1.4 and 1.9) across 5 depths spanning 34 m of an in situ CT deposit. Pyrosequence results identified a total of 29,719 bacterial 16S rRNA gene sequences, representing 131 OTUs spanning19 phyla including 7 candidate divisions, not reported in oil sands tailings pond studies to date. Legacy FFT common phyla, notably, gamma and beta Proteobacteria, Firmicutes, Actinobacteria, and Chloroflexi were represented. However, overall CT microbial diversity and PLFA values were low relative to other contexts. The identified known sulfate/sulfur reducing bacteria constituted at most 2% of the abundance; however, over 90% of the 131 OTUs identified are capable of sulfur metabolism. While PCR biases caution against overinterpretation of pyrosequence surveys, bacterial sequence results identified here, align with phospholipid fatty acid (PLFA) and geochemical results. The highest bacterial diversities were associated with the depth of highest porewater [∑H2S] (22–24 m) and joint porewater co-occurrence of Fe2+ and ∑H2S (6–8 m). Three distinct bacterial community structure depths corresponded to CT porewater regions of (1) shallow evident Fe(II) (<6 m), (2) co-occurring Fe(II) and ∑H2S (6–8 m) and (3) extensive ∑H2S (6–34 m) (UniFrac). Candidate divisions GNO2, NKB19 and Spam were present only at 6–8 m associated with co-occurring [Fe(II)] and [∑H2S]. Collectively, results indicate that CT materials are differentiated from other sulfur rich environments by modestly diverse, low abundance, but highly sulfur active and more enigmatic communities (7 candidate divisions present within the 19 phyla identified). PMID:26869997

Spatial distribution of bacterial communities and related biochemical properties in Luzhou-flavor liquor-fermented grains.

PubMed

Zheng, Jia; Wu, Chongde; Huang, Jun; Zhou, Rongqing; Liao, Xuepin

2014-12-01

Grain fermenting with separate layers in a fermentation pit is the typical and experiential brewing technology for Chinese Luzhou-flavor liquor. However, it is still unclear to what extent the bacterial communities in the different layers of fermented grains (FG) effects the liquor's quality. In this study, the spatial distributions of bacterial communities in Luzhou-flavor liquor FG (top, middle, and bottom layers) from 2 distinctive factories (Jiannanchun and Fenggu) were investigated using culture-independent approaches (phospholipid fatty acid [PLFA] and polymerase chain reaction-denaturing gel electrophoresis [DGGE]). The relationship between bacterial community and biochemical properties was also assessed by Canonical correspondence analysis (CCA). No significant variation in moisture was observed in spatial samples, and the highest content of acidity and total ester was detected in the bottom layer (P < 0.05). A high level of ethanol was observed in the top and middle layers of Fenggu and Jiannanchun, respectively. Significant spatial distribution of the total PLFA was only shown in the 50-y-old pits (P < 0.05), and Gram negative bacteria was the prominent community. Bacterial 16S rDNA DGGE analysis revealed that the most abundant bacterial community was in the top layers of the FG both from Fenggu and Jiannanchun, with Lactobacillaceae accounting for 30% of the total DGGE bands and Lactobacillus acetotolerans was the dominant species. FG samples from the same pit had a highly similar bacterial community structure according to the hierarchal cluster tree. CCA suggested that the moisture, acidity, ethanol, and reducing sugar were the main factors affecting the distribution of L. acetotolerans. Our results will facilitate the knowledge about the spatial distribution of bacterial communities and the relationship with their living environment. © 2014 Institute of Food Technologists®

Microbiology Meets Archaeology: Soil Microbial Communities Reveal Different Human Activities at Archaic Monte Iato (Sixth Century BC).

PubMed

Margesin, Rosa; Siles, José A; Cajthaml, Tomas; Öhlinger, Birgit; Kistler, Erich

2017-05-01

Microbial ecology has been recognized as useful in archaeological studies. At Archaic Monte Iato in Western Sicily, a native (indigenous) building was discovered. The objective of this study was the first examination of soil microbial communities related to this building. Soil samples were collected from archaeological layers at a ritual deposit (food waste disposal) in the main room and above the fireplace in the annex. Microbial soil characterization included abundance (cellular phospholipid fatty acids (PLFA), viable bacterial counts), activity (physiological profiles, enzyme activities of viable bacteria), diversity, and community structure (bacterial and fungal Illumina amplicon sequencing, identification of viable bacteria). PLFA-derived microbial abundance was lower in soils from the fireplace than in soils from the deposit; the opposite was observed with culturable bacteria. Microbial communities in soils from the fireplace had a higher ability to metabolize carboxylic and acetic acids, while those in soils from the deposit metabolized preferentially carbohydrates. The lower deposit layer was characterized by higher total microbial and bacterial abundance and bacterial richness and by a different carbohydrate metabolization profile compared to the upper deposit layer. Microbial community structures in the fireplace were similar and could be distinguished from those in the two deposit layers, which had different microbial communities. Our data confirmed our hypothesis that human consumption habits left traces on microbiota in the archaeological evidence; therefore, microbiological residues as part of the so-called ecofacts are, like artifacts, key indicators of consumer behavior in the past.

Shift in soil microbial communities with shrub encroachment in Inner Mongolia grasslands, China

NASA Astrophysics Data System (ADS)

Shen, H.; Li, H.; Zhang, J.; Hu, H.; Chen, L.; Zhu, Y.; Fang, J.

2017-12-01

The ongoing expansion of shrub encroachment into grasslands represents a unique form of land cover change. How this process affects soil microbial communities is poorly understood. In this study, we aim to assess the effects of shrub encroachment on soil microbial biomass, abundance and composition by comparing data between shrub patches and neighboring herb patches in shrub-encroached grasslands (SEGs) in Inner Mongolia, China. Fourteen SEG sites from two ecosystem types (typical and desert grasslands) were investigated. The phospholipid fatty acid (PLFA) method was used to analyze the composition and biomass of the soil microbial community. Our results showed that the top-soil microbial biomass and abundances of gram-negative bacteria, arbuscular mycorrhizal fungi, and actinomycetes were significantly higher in shrub patches than in herb patches in both typical and desert grasslands (P < 0.05). The fungi to bacteria ratio was significantly higher in shrub patches than in herb patches in desert grassland (P < 0.05). The microbial biomass was positively associated with mean annual precipitation, total nitrogen and available phosphorus, and negatively associated with mean annual temperature. Our results also indicated that the variation in microbial composition was largely explained by edaphic factors, followed by climate factors. In conclusion, shrub encroachment in Inner Mongolia grasslands has significantly influenced the structure and abundance of soil microbial communities, which makes the microbial communities toward a fresh organic carbon-based structure. This study highlights the importance of edaphic and climate factors in microbial community shifts in SEGs.

Molecular differentiation of subsoil biopores of different origin by PLFA analysis

NASA Astrophysics Data System (ADS)

Banfield, Callum; Pausch, Johanna; Kuzyakov, Yakov

2015-04-01

Biologically generated macropores (biopores) are a key factor for propagation of root growth, nutrient mobilisation and acquisition from the subsoil. However, biopores of different origin, i.e. root-derived, earthworm-derived or of mixed origin, are difficult to distinguish visually in the field. Therefore, the objective of this study was to test molecular differentiation by means of phospholipds fatty acids (PLFA). 24 samples of biopore content of the three aforementioned origins and 8 bulk soil samples were taken from two soil depths (45 - 75 cm; 75 - 105 cm) and extracted twice by a solution of methanol, chloroform and citrate/KOH buffer (pH 4, v:v:v = 1:2:0.8). Following separation of phospholipids, derivatisation was by hydrolysation using NaOH in MeOH and methylation by adding BF3 and heating at 80°C. After further purification and preparation, samples were measured by gas chromatography - mass spectrometry (GC-MS). Generally, the abundance of PLFA differed only slightly between the upper and lower soil depth. Gram negative bacteria (16:1w7c, 18:1w7c and Cy17:0) were the most abundant microbial group in both depths and show clear enrichment in biopores, especially in the mixed-pore type. A similiar pattern was observed for fungi (18:2w6,9), but it was less pronounced in the deeper section. Actinomycetes (10Me16:0 and 10Me18:0) in contrast, show the highest enrichment in root-derived pores. Interestingly, highest abundance of AM fungi (16:1w5c) was found not in root-derived pores, but in the mixed-pore type. Protozoa (20:4w6) occured significantly higher in the earthworm-derived biopores. The majority of the gram positive bacteria (a15:0, i15:0, i17:0 and a17:0) showed no significant preference of habitat, i.e. in this case pore type or bulk soil. This is indicative for general decomposers of old soil organic matter. Thus we showed, that PLFA analysis not only a valuable molecular proxy for the differentiation of biopore types, but also provides deep insight into the role of individual microbial functional groups in nutrient mobilisation and cycling in subsoils.

The effect of biochar amendment on the soil microbial community - PLFA analyses and 13C labeling results

NASA Astrophysics Data System (ADS)

Watzinger, A.; Feichtmair, S.; Rempt, F.; Anders, E.; Wimmer, B.; Kitzler, B.; Zechmeister-Boltenstern, S.; Horacek, M.; Zehetner, F.; Kloss, S.; Richoz, S.; Soja, G.

2012-04-01

The effects of biochar amendment on plant growth and on the chemical / physical soil characteristics are well explored but only few studies have investigated the impact on soil microorganisms. The response of the soil microbial community to biochar amendment was investigated by phospholipid fatty acid (PLFA) analysis in (i) a large scale pot experiment, (ii) a small scale pot experiment using 13C labeled biochar and (iii) an incubation study using 13C labeled biochar. In the large scale pot experiment, three different agricultural soils from Austria (Planosol, Cambisol, Chernozem) and four different types of biochar were investigated. In total, 25 treatments with 5 replicates each were set up and monitored over a year. The results from the pot experiments showed no significant influence of biochar amendment on the total microbial biomass in the first 100 days after biochar addition. However, discriminant analysis showed a distinction of biochar and control soils as well as a strong effect of the pyrolysis temperature on the microbial composition. The effect of biochar was dependent on the type of soil. In the Planosol, some PLFAs were affected positively, especially when adding biochar with a low pyrolysis temperature, in the first month. In the long term, microbial community composition altered. Growth of fungi and gram negative bacteria was enhanced. In the Chernozem, PLFAs from various microbial groups decreased in the long term. Variability in the incubation study was low. Consequently, many PLFAs were significantly affected by biochar amendment. Again, in the Planosol, gram negative bacteria, actinomycetes and, after 2 weeks, gram positive bacteria increased under biochar amendment whereas in the chernozem total microbial biomass and gram positive bacteria were negatively affected in the long term. The 13C labeling studies confirmed the low degradability of the biochar, i.e. no alteration of the content and the δ13C in the soil organic matter within 100 days, decreased CO2 emission after biochar addition and little 13C signature from the biochar in the respired CO2. The uptake of the labeled biochar into the microbial PLFAs was analysed and will provide an evidence if biochar was used as a carbon source. In addition, the long term effect of biochar amendment (beyond 100 days) on the soil microbial community is currently investigated. These results will be also presented in the oncoming meeting.

Arbuscular mycorrhiza enhance the rate of litter decomposition while inhibiting soil microbial community development

PubMed Central

Gui, Heng; Hyde, Kevin; Xu, Jianchu; Mortimer, Peter

2017-01-01

Although there is a growing amount of evidence that arbuscular mycorrhizal fungi (AMF) influence the decomposition process, the extent of their involvement remains unclear. Therefore, given this knowledge gap, our aim was to test how AMF influence the soil decomposer communities. Dual compartment microcosms, where AMF (Glomus mosseae) were either allowed access (AM+) to or excluded (AM−) from forest soil compartments containing litterbags (leaf litter from Calophyllum polyanthum) were used. The experiment ran for six months, with destructive harvests at 0, 90, 120, 150, and 180 days. For each harvest we measured AMF colonization, soil nutrients, litter mass loss, and microbial biomass (using phospholipid fatty acid analysis (PLFA)). AMF significantly enhanced litter decomposition in the first 5 months, whilst delaying the development of total microbial biomass (represented by total PLFA) from T150 to T180. A significant decline in soil available N was observed through the course of the experiment for both treatments. This study shows that AMF have the capacity to interact with soil microbial communities and inhibit the development of fungal and bacterial groups in the soil at the later stage of the litter decomposition (180 days), whilst enhancing the rates of decomposition. PMID:28176855

Molecular microbial and chemical investigation of the bioremediation of two-phase olive mill waste using laboratory-scale bioreactors.

PubMed

Morillo, J A; Aguilera, M; Antízar-Ladislao, B; Fuentes, S; Ramos-Cormenzana, A; Russell, N J; Monteoliva-Sánchez, M

2008-05-01

Two-phase olive mill waste (TPOMW) is a semisolid effluent that is rich in contaminating polyphenols and is produced in large amounts by the industry of olive oil production. Laboratory-scale bioreactors were used to investigate the biodegradation of TPOMW by its indigenous microbiota. The effect of nutrient addition (inorganic N and P) and aeration of the bioreactors was studied. Microbial changes were investigated by PCR-temperature time gradient electrophoresis (TTGE) and following the dynamics of polar lipid fatty acids (PLFA). The greatest decrease in the polyphenolic and organic matter contents of bioreactors was concomitant with an increase in the PLFA fungal/bacterial ratio. Amplicon sequences of nuclear ribosomal internal transcribed spacer region (ITS) and 16S rDNA allowed identification of fungal and bacterial types, respectively, by comparative DNA sequence analyses. Predominant fungi identified included members of the genera Penicillium, Candida, Geotrichum, Pichia, Cladosporium, and Aschochyta. A total of 14 bacterial genera were detected, with a dominance of organisms that have previously been associated with plant material. Overall, this work highlights that indigenous microbiota within the bioreactors through stimulation of the fungal fraction, is able to degrade the polyphenolic content without the inoculation of specific microorganisms.

Variable effects of plant colonization on black slate uptake into microbial PLFAs

NASA Astrophysics Data System (ADS)

Seifert, Anne-Gret; Trumbore, Susan; Xu, Xiaomei; Zhang, Dachung; Gleixner, Gerd

2013-04-01

Microbial degradation of carbon derived from black shale and slate has been shown in vitro. However, in natural settings where other labile carbon sources are likely to exist, this has not been previously demonstrated. We investigated the uptake of ancient carbon derived from slate weathering and from recently photosynthesised organic matter by different groups of microorganisms. Therefore we isolated microbial biomarkers (phospholipid fatty acids, PLFAs) from black slates collected at a chronosequence of waste piles which differed in age and vegetation cover. We quantified the amount of PLFAs and performed stable isotope and radiocarbon measurements on individual or grouped PLFAs to quantify the fraction of slate derived carbon. We used black slate from a pile heaped in the 1950s with either uncovered black slate material (bare site) or material slightly colonized by small plants (greened site) and from a forested leaching pile (forested site) used for alum-mining in the 19th century. Colonization by plants influenced the amount and composition of the microbial community. Greater amounts of PLFAs (5410 ng PLFA/g dw) were extracted from slate sampled at the forested site as opposed to the bare site (960 ng PLFAs/g dw) or the greened (annual grasses and mosses) rock waste pile (1050 ng PLFAs/g dw). We found the highest proportion of PLFAs representing Gram-negative bacteria on the forested site and the highest proportion of PLFAs representing Gram-positive bacteria on the bare site. The fungal PLFA was most abundant at the greened site. Sites with less plant colonization (bare and greened site) tended to have more depleted δ13C values compared to the forested site. Radiocarbon measurements on PLFAs indicated that fungi and Gram-positive bacteria were best adapted to black slate carbon uptake. In the fungal PLFA (combined bare and greened waste pile sample) and in PLFAs of Gram-positive bacteria (greened site) we measured 39.7% and 28.9% ancient carbon uptake, respectively. Our results prove that black slate degradation followed by carbon uptake takes place in situ. Results imply that plant colonization might additionally affect this process. Slight colonization with few plants increased slate derived carbon uptake in PLFAs of Gram-positive bacteria. Evidently, Gram-positive bacteria represented by specific PLFAs from the greened site held more ancient carbon than from the bare site. In contrast, no black slate derived carbon was used by microorganisms at the forested site with 2-3 times greater carbon content. Results suggest that the use of ancient slate derived carbon dominates mainly in early stages of microbial colonization of surfaces and that with increasing ecosystem development recycling of plant derived carbon dominates.

Impacts of Deepwater Horizon Oil on Marsh Sediment Biogeochemistry in Barataria Bay, LA, USA

NASA Astrophysics Data System (ADS)

Mills, C. T.; Windham-Myers, L.; Waldrop, M. P.; Krabbenhoft, D. P.; Marvin-DiPasquale, M. C.; Orem, W. H.; Piazza, S.; Haw, M.; McFarland, J.; Varonka, M. S.

2012-12-01

Oil from the Deepwater Horizon spill came ashore on many salt marsh islands in Barataria Bay, LA in summer 2010, coating plants and settling on the sediment surface. In coordination with a plant community study of affected marshes, we investigated impacts of oiling on marsh sediment microbial biogeochemistry. Sediment samples (upmost 2 cm) were collected along transects perpendicular and parallel to the shore at three oiled and three non-oiled sites in both July and Oct. 2011. Samples from both collections were analyzed for sediment characteristics, total and methylmercury, and microbial membrane phospholipid fatty acids (PLFAs) which are a proxy for viable microbial cell numbers. Sediment DNA collected in Oct. 2011 was analyzed for bacterial, fungal, and archaeal community composition and abundance as well as various enzyme activities. Select Oct. 2011 samples were assayed to determine the rates of terminal electron accepting processes (oxygen demand, denitrification, iron reduction, sulfate reduction, methanogenesis). All sites had similar sediment characteristics. Impacts on sediment biogeochemistry were greatest at marsh edges, and reduced microbial abundance appeared to be more important than changes in microbial community structure. In July 2011, the mean PLFA concentration in oiled marsh edge sediments (0.15±0.03 μmol g-1; 95% CI; n=9) was substantially lower than for non-oiled sites (0.33±0.08 μmol g-1; n=9). Mean PLFA concentrations for interior marsh samples were more similar for oiled (0.30±0.08 μmol g-1; n=8) and non-oiled (0.37±0.04 μmol g-1; n=9) sites. This PLFA pattern was also observed in Oct. 2011 samples, and other measures of microbial abundance and activity showed similar trends. Cellulase, phosphatase, and chitinase mean activities were nearly twice as great in non-oiled versus oiled edge sites. Lower microbial activity in oiled sites was also inferred by somewhat lower denitrification and sulfate reduction potentials. Conversely, both methanogenesis rates and concentrations of methanogen DNA were somewhat greater in oiled edge samples, suggesting an effect of oiling on terminal electron accepting processes. The mean methylmercury concentration was lower in oiled versus non-oiled edge sites, likely as a result of decreased sulfate-reducer activity. The reduced microbial activity in near-edge sediments of the oiled marsh is likely an indirect effect of reduced plant productivity which supports rhizosphere communities. Both mean above- and below-ground live biomass at oiled edge sites were less than half that at non-oiled edge sites. Some marsh edge samples from the oiled site contained relatively large amounts of oil and we are currently quantifying oil-derived hydrocarbons to understand impacts of the oil itself on sediment biogeochemistry.

Fast and sensitive in vivo studies under controlled environmental conditions to substitute long-term field trials with genetically modified plants.

PubMed

Horn, Patricia; Schlichting, André; Baum, Christel; Hammesfahr, Ute; Thiele-Bruhn, Sören; Leinweber, Peter; Broer, Inge

2017-02-10

We introduce an easy, fast and effective method to analyze the influence of genetically modified (GM) plants on soil and model organisms in the laboratory to substitute laborious and time consuming field trials. For the studies described here we focused on two GM plants of the so-called 3rd generation: GM plants producing pharmaceuticals (PMP) and plant made industrials (PMI). Cyanophycin synthetase (cphA) was chosen as model for PMI and Choleratoxin B (CTB) as model for PMP. The model genes are expressed in transgenic roots of composite Vicia hirsuta plants grown in petri dishes for semi-sterile growth or small containers filled with non-sterile soil. No significant influence of the model gene expression on root induction, growth, biomass, interaction with symbionts such as rhizobia (number, size and functionality of nodules, selection of nodulating strains) or arbuscular mycorrhizal fungi could be detected. In vitro, but not in situ under field conditions, structural diversity of the bulk soil microbial community between transgenic and non-transgenic cultivars was determined by PLFA pattern-derived ratios of bacteria: fungi and of gram + : gram - bacteria. Significant differences in PLFA ratios were associated with dissimilarities in the quantity and molecular composition of rhizodeposits as revealed by Py-FIMS analyses. Contrary to field trials, where small effects based on the transgene expression might be hidden by the immense influence of various environmental factors, our in vitro system can detect even minor effects and correlates them to transgene expression with less space, time and labour. Copyright © 2016 Elsevier B.V. All rights reserved.

Turnover of microbial groups and cell components in soil: 13C analysis of cellular biomarkers

NASA Astrophysics Data System (ADS)

Gunina, Anna; Dippold, Michaela; Glaser, Bruno; Kuzyakov, Yakov

2017-01-01

Microorganisms regulate the carbon (C) cycle in soil, controlling the utilization and recycling of organic substances. To reveal the contribution of particular microbial groups to C utilization and turnover within the microbial cells, the fate of 13C-labelled glucose was studied under field conditions. Glucose-derived 13C was traced in cytosol, amino sugars and phospholipid fatty acid (PLFA) pools at intervals of 3, 10 and 50 days after glucose addition into the soil. 13C enrichment in PLFAs ( ˜ 1.5 % of PLFA C at day 3) was an order of magnitude greater than in cytosol, showing the importance of cell membranes for initial C utilization. The 13C enrichment in amino sugars of living microorganisms at day 3 accounted for 0.57 % of total C pool; as a result, we infer that the replacement of C in cell wall components is 3 times slower than that of cell membranes. The C turnover time in the cytosol (150 days) was 3 times longer than in PLFAs (47 days). Consequently, even though the cytosol pool has the fastest processing rates compared to other cellular compartments, intensive recycling of components here leads to a long C turnover time. Both PLFA and amino-sugar profiles indicated that bacteria dominated in glucose utilization. 13C enrichment decreased with time for bacterial cell membrane components, but it remained constant or even increased for filamentous microorganisms. 13C enrichment of muramic acid was the 3.5 times greater than for galactosamine, showing a more rapid turnover of bacterial cell wall components compared to fungal. Thus, bacteria utilize a greater proportion of low-molecular-weight organic substances, whereas filamentous microorganisms are responsible for further C transformations. Thus, tracing 13C in cellular compounds with contrasting turnover rates elucidated the role of microbial groups and their cellular compartments in C utilization and recycling in soil. The results also reflect that microbial C turnover is not restricted to the death or growth of new cells. Indeed, even within living cells, highly polymeric cell compounds are constantly replaced and renewed. This is especially important for assessing C fluxes in soil and the contribution of C from microbial residues to soil organic matter.

Effects of ammonium-based ionic liquids and 2,4-dichlorophenol on the phospholipid fatty acid composition of zebrafish embryos

PubMed Central

Piotrowska, Aleksandra; Syguda, Anna; Wyrwas, Bogdan; Chrzanowski, Lukasz; Luckenbach, Till

2018-01-01

Ionic liquids consisting of a combination of herbicidal anions with a quaternary ammonium cation act as efficient herbicides, which are under consideration to be used in the agriculture. In the present study, we used embryos of the zebrafish (Danio rerio) as a model to assess the toxic potential of ammonium-based ionic liquids for aquatic organisms. As we assumed interference of the partially hydrophobic ionic liquid cation with lipids, we investigated the adaptation response in the lipid composition of the zebrafish embryos, triggered by the ionic compound. Therefore, the impact of ammonium-based ionic liquids with different lengths of the alkyl chain ([C6,C6,C1,C1N][Br], [C8,C8,C1,C1N][Br]) on the phospholipid fatty acid (PLFA) profile of zebrafish embryos up to 72 hours post fertilization (hpf) was examined. Furthermore, the changes in the unsaturation index (UI) of PLFAs, as the sum parameter of membrane fluidity in eukaryotic cells, were presented. The PLFA’s UI in the zebrafish embryos upon exposure to quaternary ammonium salts was compared to the UI of the embryos upon exposure to nonionic 2,4-dichlorophenol, which has a similar hydrophobicity but is structurally different to [C8,C8,C1,C1N][Br]. It was shown that for ammonium-based ionic liquid precursors non-specific mode of action occurs and the toxic effect on lipid composition of zebrafish embryos can be well predicted based on chemical properties, like hydrophobicity. Furthermore, the changes in PLFAs, expressed by the UI, can be useful to study toxic effects of organic contamination. However, for zebrafish embryos, after ionic liquids and 2,4-DCP exposure, the changes were observed at high lethal concentrations, which caused the incidence of lethality of 30 and 50% of a group of test animals. PMID:29342167

The impact of zero-valent iron nanoparticles upon soil microbial communities is context dependent.

PubMed

Pawlett, Mark; Ritz, Karl; Dorey, Robert A; Rocks, Sophie; Ramsden, Jeremy; Harris, Jim A

2013-02-01

Nanosized zero-valent iron (nZVI) is an effective land remediation tool, but there remains little information regarding its impact upon and interactions with the soil microbial community. nZVI stabilised with sodium carboxymethyl cellulose was applied to soils of three contrasting textures and organic matter contents to determine impacts on soil microbial biomass, phenotypic (phospholipid fatty acid (PLFA)), and functional (multiple substrate-induced respiration (MSIR)) profiles. The nZVI significantly reduced microbial biomass by 29 % but only where soil was amended with 5 % straw. Effects of nZVI on MSIR profiles were only evident in the clay soils and were independent of organic matter content. PLFA profiling indicated that the soil microbial community structure in sandy soils were apparently the most, and clay soils the least, vulnerable to nZVI suggesting a protective effect imparted by clays. Evidence of nZVI bactericidal effects on Gram-negative bacteria and a potential reduction of arbuscular mycorrhizal fungi are presented. Data imply that the impact of nZVI on soil microbial communities is dependent on organic matter content and soil mineral type. Thereby, evaluations of nZVI toxicity on soil microbial communities should consider context. The reduction of AM fungi following nZVI application may have implications for land remediation.

Effects of forest conversion on soil microbial communities depend on soil layer on the eastern Tibetan Plateau of China.

PubMed

He, Ruoyang; Yang, Kaijun; Li, Zhijie; Schädler, Martin; Yang, Wanqin; Wu, Fuzhong; Tan, Bo; Zhang, Li; Xu, Zhenfeng

2017-01-01

Forest land-use changes have long been suggested to profoundly affect soil microbial communities. However, how forest type conversion influences soil microbial properties remains unclear in Tibetan boreal forests. The aim of this study was to explore variations of soil microbial profiles in the surface organic layer and subsurface mineral soil among three contrasting forests (natural coniferous forest, NF; secondary birch forest, SF and spruce plantation, PT). Soil microbial biomass, activity and community structure of the two layers were investigated by chloroform fumigation, substrate respiration and phospholipid fatty acid analysis (PLFA), respectively. In the organic layer, both NF and SF exhibited higher soil nutrient levels (carbon, nitrogen and phosphorus), microbial biomass carbon and nitrogen, microbial respiration, PLFA contents as compared to PT. However, the measured parameters in the mineral soils often did not differ following forest type conversion. Irrespective of forest types, the microbial indexes generally were greater in the organic layer than in the mineral soil. PLFAs biomarkers were significantly correlated with soil substrate pools. Taken together, forest land-use change remarkably altered microbial community in the organic layer but often did not affect them in the mineral soil. The microbial responses to forest land-use change depend on soil layer, with organic horizons being more sensitive to forest conversion.

Rapid Shifts in Soil and Forest Floor Microbial Communities with Changes in Vegetation during Secondary Tropical Forest Succession

NASA Astrophysics Data System (ADS)

Smith, A.; Marin-Spiotta, E.; Balser, T. C.

2012-12-01

Soil microorganisms regulate fundamental biochemical processes in plant litter decomposition and soil organic matter (SOM) transformations. In order to predict how disturbance affects belowground carbon storage, it is important to understand how the forest floor and soil microbial community respond to changes in land cover, and the consequences on SOM formation and stabilization. We are measuring microbial functional diversity and activity across a long-term successional chronosequence of secondary forests regrowing on abandoned pastures in the wet subtropical forest life zone of Puerto Rico. Here we report intra- and interannual data on soil and litter microbial community composition (via phospholipid fatty acid analysis, PLFA) and microbial activity (via extracellular enzyme activity) from active pastures, secondary forests aged 20, 30, 40, 70, and 90-years, and primary forests. Microbial community composition and extracellular enzyme activity differed significantly by season in these wet subtropical ecosystems, even though differences in mean monthly precipitation between the middle of the dry season (January) and the wet season (July) is only 30mm. Despite seasonal differences, there was a persistent strong effect of land cover type and forest successional stage, or age, on overall microbial community PLFA structure. Using principal component analysis, we found differences in microbial community structure among active pastures, early, and late successional forests. The separation of soil microbes into early and late successional communities parallels the clustering of tree composition data. While the successional patterns held across seasons, the importance of different microbial groups driving these patterns differed seasonally. Biomarkers for gram-positive and actinobacteria (i15:0 and 16:0 10Me) were associated with early (20, 30 & 40 year old) secondary forests in the dry season. These younger forest communities were identified by the biomarker for anaerobic gram-negative bacteria (c19:0) in the wet season, which suggests the presence of anaerobic microsites in these very clayey Oxisols. Enzymatic activity did not differ with succession but was highest in the dry season. We expect this may be due to decreased turnover of enzymes with low soil moisture. Interannual sampling has revealed a very rapid microbial response to changes in aboveground cover. Within a year following woody biomass encroachment, we detected a shift in the soil microbial community from a pasture-associated community to an early secondary forest community in one of our replicate pasture sites. This very rapid response in the belowground microbial community structure to changes in vegetation has not been strongly documented in the literature. This data supports a direct link between aboveground and belowground biotic community structures and highlights the importance of long-term repeated sampling of microbial communities in dynamic ecosystems. Our findings have implications for predicting rapid ecological responses to land-cover change.

Microbial and Dissolved Organic Carbon Characterization of Stormflow in the Santa Ana River at Imperial Highway, Southern California, 1999-2002

USGS Publications Warehouse

Izbicki, John A.; Pimentel, M. Isabel; Leddy, Menu; Bergamaschi, Brian A.

2004-01-01

The Santa Ana River drains about 2,670 square miles of densely populated coastal southern California, near Los Angeles. Almost all the flow in the river, more than 200,000 acre-feet annually, is diverted to ponds where it infiltrates and recharges underlying aquifers pumped to supply water for more than 2 million people. Base flow in the river is almost entirely treated municipal wastewater discharged from upstream treatment plants and, in the past, stormflow was considered a source of high-quality water suitable for use as a source of ground-water recharge that would dilute poorer quality water recharged during base flow. Stormflow in the Santa Ana River at the Imperial Highway diversion contains total coliform bacteria concentrations as high as 3,400,000 colonies per 100 mL (milliliters). Fecal indicator bacteria concentrations, including fecal coliforms, Escherichia coli, and enterococci, were as high as 310,000, 84,000, and 102,000 colonies per 100 mL, respectively. Although concentrations were high owing to urban runoff during the first stormflow of the rainy season, the highest concentrations occurred during the recessional flows of the first stormflow of the rainy season after streamflow returned to pre-storm conditions. Molecular indicators of microbiological organisms in stormflow, including phospholipid fatty acid (PLFA) and genetic data, show that the diversity of the total microbial population decreases during stormflow while fecal indicator bacteria concentrations increase. This suggests that the source of the bacteria must be poorly diverse and dominated by only a few types of bacteria. Although direct runoff of fecal indicator bacteria from urban areas occurs, this process cannot explain the very high concentrations of fecal indicator bacteria in runoff from upstream parts of the basin characterized by urban, agricultural (including more than 300,000 head of dairy cattle), and other land uses. Although other explanations are possible, fecal indicator bacteria concentrations and molecular microbiological data indicate accumulation and extended survival of bacteria in streambed sediments, and subsequent mobilization of those sediments and associated bacteria during stormflow. Both PLFA and genetic data indicate that water from dairy-waste storage ponds was not present during sampled stormflows. This is consistent with the relatively dry conditions and the absence of large stormflows during the study. Dissolved organic carbon (DOC) concentrations in stormflow ranged from 3 to 15.3 mg/L. In general, concentrations increased during stormflow and were distributed across the stormflow hydrograph in a manner similar to that of fecal indicator bacteria. DOC concentrations typically remained high for several days after flow returned to pre-storm conditions. Ultraviolet absorbance, excitation emission spectroscopy, and sequential fractionation of DOC using XAD-8 and XAD-4 resins showed that the composition of DOC changed rapidly during stormflow. Hydrophobic and hydrophilic acids were the largest fraction of DOC composing between 27 and 45 percent and between 24 and 37 percent of the DOC, respectively. The fraction of DOC composed of hydrophobic acids decreased due to urban runoff and increased during the recession of the first stormflow of the rainy season; the hydrophilic-acid fraction generally decreased throughout the stormflow hydrograph; the transhydrophilic-acid fraction did not vary greatly during stormflow; and the hydrophobic-neutral fraction increased from low values in base flow to almost 30 percent of the DOC after more soluble and more mobile hydrophobic and hydrophilic acids were washed from urban areas. Comparison of ultraviolet absorbance data with data collected during previous studies shows that the optical properties and, presumably, the composition of the DOC were different in this study than DOC collected during wetter periods. Samples of shallow ground water collec

Utilisation of young and old soil carbon sources by microbial groups differ during the growing season and between experimental treatments in a long-term field experiment

NASA Astrophysics Data System (ADS)

Börjesson, Gunnar; Menichetti, Lorenzo; Thornton, Barry; Campbell, Colin; Kätterer, Thomas

2014-05-01

Soil organic matter (SOM)is the largest active carbon pool in the terrestrial environment. SOM is a key factor for soil fertility, but is also important for the sequestration of atmospheric CO2. In agricultural soils, management of plant residues and the use of organic fertilisers play important roles for maintaining SOM. Switching from C3 plants to C4 plants such as maize, enables a natural labelling in situ; when coupled with compound specific 13C isotope analysis of phospholipid fatty acids (PLFAs) it allows the proportion of new C (fixed after the switch added to soil from above- and belowground litter and root exudates) and the proportion of old C (fixed prior to the switch derived from turnover of organic matter) utilised by the soil microbial community to be determined. (new paragraph) A field experiment in Sweden, amended with different mineral and organic fertilisers since 1956, was grown with C3 plants, mainly cereals until 1999. From the year 2000 silage maize was grown every year. In 2012, soil from four replicate plots of five experimental treatments, N fertilised, N fertilised amended with straw and sewage sludge, and two controls (bare fallow and cropped unfertilised) were sampled three times, at the start, middle and end of the growing season. Phospholipid fatty acids (PLFAs) were extracted from all soil samples and analysed for concentrations and 13C content. (new paragraph) Total PLFA concentrations and also the PLFA/SOM ratios increased with SOM in the different treatments. Seasonal variation in total PLFA was small except for the most SOM-rich treatment (sewage sludge) where concentrations significantly decreased during the growing season indicating the depletion of a labile SOM pool. Weighted mean values of δ13C in PLFAs show that the plots fertilised with only calcium nitrate had the highest δ13C-values in PLFAs before (-20.24 o) and after the vegetation period (-20.37 o), due to a large input of 13C-enriched plant material. However, during the vegetation period the values were much lower (-21.85 o). This coincided with a strong increase of the PLFA 18:2 (from 0.99 up to 2.37 nmol g dry wt soil-1), indicating utilisation of old organic matter by fungi, while mono-unsaturated PLFAs, indicating Gram-negative bacteria, were more frequent before and after the growing season. Microbial dynamics in the unfertilised control followed the same seasonal pattern but PLFAs were less enriched in 13C due to lower yields compared with the N-fertilised treatment. The addition of organic amendments (straw or sewage sludge) lowered δ13C-values in PLFAs below values of the control due to input of labile material with C3-origin. PLFAs in the bare fallow treatment, that had not received plant carbon inputs during twelve years, were most 13C depleted among the treatments but still enriched by about 2o compared with SOM, indicating a degree of microbial fractionation.

Quinone-based stable isotope probing for assessment of 13C substrate-utilizing bacteria

NASA Astrophysics Data System (ADS)

Kunihiro, Tadao; Katayama, Arata; Demachi, Toyoko; Veuger, Bart; Boschker, Henricus T. S.; van Oevelen, Dick

2015-04-01

In this study, we attempted to establish quinone-stable-isotope probing (SIP) technique to link substrate-utilizing bacterial group to chemotaxonomic group in bacterial community. To identify metabolically active bacterial group in various environments, SIP techniques combined with biomarkers have been widely utilized as an attractive method for environmental study. Quantitative approaches of the SIP technique have unique advantage to assess substrate-incorporation into bacteria. As a most major quantitative approach, SIP technique based on phospholipid-derived fatty acids (PLFA) have been applied to simultaneously assess substrate-incorporation rate into bacteria and microbial community structure. This approach is powerful to estimate the incorporation rate because of the high sensitivity due to the detection by a gas chromatograph-combustion interface-isotope ratio mass spectrometer (GC-c-IRMS). However, its phylogenetic resolution is limited by specificity of a compound-specific marker. We focused on respiratory quinone as a biomarker. Our previous study found a good correlation between concentrations of bacteria-specific PLFAs and quinones over several orders of magnitude in various marine sediments, and the quinone method has a higher resolution (bacterial phylum level) for resolving differences in bacterial community composition more than that of bacterial PLFA. Therefore, respiratory quinones are potentially good biomarkers for quantitative approaches of the SIP technique. The LC-APCI-MS method as molecular-mass based detection method for quinone was developed and provides useful structural information for identifying quinone molecular species in environmental samples. LC-MS/MS on hybrid triple quadrupole/linear ion trap, which enables to simultaneously identify and quantify compounds in a single analysis, can detect high molecular compounds with their isotope ions. Use of LC-MS/MS allows us to develop quinone-SIP based on molecular mass differences due to 13C abundance in the quinone. In this study, we verified carbon stable isotope of quinone compared with bulk carbon stable isotope of bacterial culture. Results indicated a good correlation between carbon stable isotope of quinone compared with bulk carbon stable isotope. However, our measurement conditions for detection of quinone isotope-ions incurred underestimation of 13C abundance in the quinone. The quinone-SIP technique needs further optimization for measurement conditions of LC-MS/MS.

Rhizospheric Bacterial Strain Brevibacterium casei MH8a Colonizes Plant Tissues and Enhances Cd, Zn, Cu Phytoextraction by White Mustard.

PubMed

Płociniczak, Tomasz; Sinkkonen, Aki; Romantschuk, Martin; Sułowicz, Sławomir; Piotrowska-Seget, Zofia

2016-01-01

Environmental pollution by heavy metals has become a serious problem in the world. Phytoextraction, which is one of the plant-based technologies, has attracted the most attention for the bioremediation of soils polluted with these contaminants. The aim of this study was to determine whether the multiple-tolerant bacterium, Brevibacterium casei MH8a isolated from the heavy metal-contaminated rhizosphere soil of Sinapis alba L., is able to promote plant growth and enhance Cd, Zn, and Cu uptake by white mustard under laboratory conditions. Additionally, the ability of the rifampicin-resistant spontaneous mutant of MH8a to colonize plant tissues and its mechanisms of plant growth promotion were also examined. In order to assess the ecological consequences of bioaugmentation on autochthonous bacteria, the phospholipid fatty acid (PLFA) analysis was used. The MH8a strain exhibited the ability to produce ammonia, 1-amino-cyclopropane-1-carboxylic acid deaminase, indole 3-acetic acid and HCN but was not able to solubilize inorganic phosphate and produce siderophores. Introduction of MH8a into soil significantly increased S. alba biomass and the accumulation of Cd (208%), Zn (86%), and Cu (39%) in plant shoots in comparison with those grown in non-inoculated soil. Introduced into the soil, MH8a was able to enter the plant and was found in the roots and leaves of inoculated plants thus indicating its endophytic features. PLFA analysis revealed that the MH8a that was introduced into soil had a temporary influence on the structure of the autochthonous bacterial communities. The plant growth-promoting features of the MH8a strain and its ability to enhance the metal uptake by white mustard and its long-term survival in soil as well as its temporary impact on autochthonous microorganisms make the strain a suitable candidate for the promotion of plant growth and the efficiency of phytoextraction.

Rhizospheric Bacterial Strain Brevibacterium casei MH8a Colonizes Plant Tissues and Enhances Cd, Zn, Cu Phytoextraction by White Mustard

PubMed Central

Płociniczak, Tomasz; Sinkkonen, Aki; Romantschuk, Martin; Sułowicz, Sławomir; Piotrowska-Seget, Zofia

2016-01-01

Environmental pollution by heavy metals has become a serious problem in the world. Phytoextraction, which is one of the plant-based technologies, has attracted the most attention for the bioremediation of soils polluted with these contaminants. The aim of this study was to determine whether the multiple-tolerant bacterium, Brevibacterium casei MH8a isolated from the heavy metal-contaminated rhizosphere soil of Sinapis alba L., is able to promote plant growth and enhance Cd, Zn, and Cu uptake by white mustard under laboratory conditions. Additionally, the ability of the rifampicin-resistant spontaneous mutant of MH8a to colonize plant tissues and its mechanisms of plant growth promotion were also examined. In order to assess the ecological consequences of bioaugmentation on autochthonous bacteria, the phospholipid fatty acid (PLFA) analysis was used. The MH8a strain exhibited the ability to produce ammonia, 1-amino-cyclopropane-1-carboxylic acid deaminase, indole 3-acetic acid and HCN but was not able to solubilize inorganic phosphate and produce siderophores. Introduction of MH8a into soil significantly increased S. alba biomass and the accumulation of Cd (208%), Zn (86%), and Cu (39%) in plant shoots in comparison with those grown in non-inoculated soil. Introduced into the soil, MH8a was able to enter the plant and was found in the roots and leaves of inoculated plants thus indicating its endophytic features. PLFA analysis revealed that the MH8a that was introduced into soil had a temporary influence on the structure of the autochthonous bacterial communities. The plant growth-promoting features of the MH8a strain and its ability to enhance the metal uptake by white mustard and its long-term survival in soil as well as its temporary impact on autochthonous microorganisms make the strain a suitable candidate for the promotion of plant growth and the efficiency of phytoextraction. PMID:26909087

Reprint of "Fast and sensitive in vivo studies under controlled environmental conditions to substitute long-term field trials with genetically modified plants".

PubMed

Horn, Patricia; Schlichting, André; Baum, Christel; Hammesfahr, Ute; Thiele-Bruhn, Sören; Leinweber, Peter; Broer, Inge

2017-09-10

We introduce an easy, fast and effective method to analyze the influence of genetically modified (GM) plants on soil and model organisms in the laboratory to substitute laborious and time consuming field trials. For the studies described here we focused on two GM plants of the so-called 3rd generation: GM plants producing pharmaceuticals (PMP) and plant made industrials (PMI). Cyanophycin synthetase (cphA) was chosen as model for PMI and Choleratoxin B (CTB) as model for PMP. The model genes are expressed in transgenic roots of composite Vicia hirsuta plants grown in petri dishes for semi-sterile growth or small containers filled with non-sterile soil. No significant influence of the model gene expression on root induction, growth, biomass, interaction with symbionts such as rhizobia (number, size and functionality of nodules, selection of nodulating strains) or arbuscular mycorrhizal fungi could be detected. In vitro, but not in situ under field conditions, structural diversity of the bulk soil microbial community between transgenic and non-transgenic cultivars was determined by PLFA pattern-derived ratios of bacteria: fungi and of gram + : gram - bacteria. Significant differences in PLFA ratios were associated with dissimilarities in the quantity and molecular composition of rhizodeposits as revealed by Py-FIMS analyses. Contrary to field trials, where small effects based on the transgene expression might be hidden by the immense influence of various environmental factors, our in vitro system can detect even minor effects and correlates them to transgene expression with less space, time and labour. Copyright © 2016 Elsevier B.V. All rights reserved.

Diel fluctuations in natural organic matter quality in an oligotrophic cave system

NASA Astrophysics Data System (ADS)

Brown, T.; Engel, A. S.; Pfiffner, S. M.

2016-12-01

Transformations of natural organic matter (NOM) and effects of photochemical degradation on dissolved organic matter (DOM) quality in recharge can be readily studied in cave systems with hydrologic connections between the surface and subsurface. Specifically, diel controls on photodegradation, fresh NOM production, and microbial C cycling were examined from recharge to resurgence of an oligotrophic cave stream in Kentucky. We used NOM isolation and spectroscopic analysis to concentrate and characterize DOM, and lipid profiling to evaluate microbial community structure. A hydrophilic fraction of DOM was isolated from bulk waters in the field using diethylaminoethyl (DEAE) weak anion exchange column chromatography, and isolates were characterized with FTIR spectroscopy to identify differences in macromolecular structure between surface and subsurface (downstream) DOM. Lipids from colloidal NOM (retained on 0.2 µm filter) and stream sediments were extracted using a modified Bligh Dyer method, segregated into classes, and converted to fatty acid methyl esters (FAME) for quantification and identification by GC-MS. During a late summer, low flow, 24-hour sampling event, the quality of surface water DOM recharged at night was 40% richer in aliphatic esters, 30% richer in phenols and alkanes, and elevated in polysaccharides compared with DOM recharged during daylight. IR absorptivity in nocturnal DOM isolates was an order of magnitude lower in the cave stream, with recalcitrant DOM interpreted from bands of aliphatic esters, alkanes, and organo-silicates. Phospholipid fatty acid (PLFA) profiles indicated that the abundance of polyunsaturated PLFA associated with algae, fungi, and higher plants decreased along the flowpath. Cave microbes exhibited elevated trans:cis ratios relative to surface communities, and the ratio increased at night. This suggested that downstream microbial communities existed in a state of reduced activity without inputs of photosynthates at night.

[Effects of biochar and sheep manure on rhizospheric soil microbial community in continuous ratooning tea orchards].

PubMed

Li, Yan Chun; Li, Zhao Wei; Lin, Wei Wei; Jiang, Yu Hang; Weng, Bo Qi; Lin, Wen Xiong

2018-04-01

Long-term continuous ratooning of tea could lead to serious soil acidification, nutritional imbalance, and the deterioration of the rhizosphere micro-ecological environment. Understanding the effects of biochar and sheep manure on the growth of tea plants and the rhizosphere microbial community structure and function would provide theoretical basis to improve the soil micro-ecological environment of continuous ratooning tea orchards. Biolog technology combined with phospholipid fatty acid (PLFA) approaches were employed to quantify the effects of biochar (40 t·hm -2 ) and sheep manure on the growth of 20 years continuous ratooning tea plants, soil chemical properties, and the soil microbial community structure and function. The results showed that after one year treatment, biochar and sheep manure both improved soil pH and nutrition, and significantly enhanced tea production. Compared with the routine fertilizer application (CK), the biochar and sheep manure treatments significantly increased the carbon metabolic activity (AWCD) and microorganism diversity in the rhizosphere soils, and increased the relative utilization of the carbon sources such as amines, carbohydrates, and polymers. The total PLFA concentrations in the biochar and sheep manure treatments were significantly increased by 20.9% and 47.5% than that in the routine fertilizers application. In addition, sheep manure treatment significantly decreased the saturated/monosaturated fatty acids In conclusion, biochar and sheep manure could alleviate soil acidification, enhance soil nutrition and the growth of tea plants. Both management strategies could increase the soil microbial activity and biomass, enhance the diversity, and improve the microbial community structure, which could be taken as effective measures to regulate the rhizosphere micro-environment of tea plants.

Characterization of NaCl tolerance in Desulfovibrio vulgaris Hildenborough through experimental evolution

PubMed Central

Zhou, Aifen; Baidoo, Edward; He, Zhili; Mukhopadhyay, Aindrila; Baumohl, Jason K; Benke, Peter; Joachimiak, Marcin P; Xie, Ming; Song, Rong; Arkin, Adam P; Hazen, Terry C; Keasling, Jay D; Wall, Judy D; Stahl, David A; Zhou, Jizhong

2013-01-01

Desulfovibrio vulgaris Hildenborough strains with significantly increased tolerance to NaCl were obtained via experimental evolution. A NaCl-evolved strain, ES9-11, isolated from a population cultured for 1200 generations in medium amended with 100 mM NaCl, showed better tolerance to NaCl than a control strain, EC3-10, cultured for 1200 generations in parallel but without NaCl amendment in medium. To understand the NaCl adaptation mechanism in ES9-11, we analyzed the transcriptional, metabolite and phospholipid fatty acid (PLFA) profiles of strain ES9-11 with 0, 100- or 250 mM-added NaCl in medium compared with the ancestral strain and EC3-10 as controls. In all the culture conditions, increased expressions of genes involved in amino-acid synthesis and transport, energy production, cation efflux and decreased expression of flagellar assembly genes were detected in ES9-11. Consistently, increased abundances of organic solutes and decreased cell motility were observed in ES9-11. Glutamate appears to be the most important osmoprotectant in D. vulgaris under NaCl stress, whereas, other organic solutes such as glutamine, glycine and glycine betaine might contribute to NaCl tolerance under low NaCl concentration only. Unsaturation indices of PLFA significantly increased in ES9-11. Branched unsaturated PLFAs i17:1 ω9c, a17:1 ω9c and branched saturated i15:0 might have important roles in maintaining proper membrane fluidity under NaCl stress. Taken together, these data suggest that the accumulation of osmolytes, increased membrane fluidity, decreased cell motility and possibly an increased exclusion of Na+ contribute to increased NaCl tolerance in NaCl-evolved D. vulgaris. PMID:23575373

Microbial ecology in a future climate: effects of temperature and moisture on microbial communities of two boreal fens.

PubMed

Peltoniemi, Krista; Laiho, Raija; Juottonen, Heli; Kiikkilä, Oili; Mäkiranta, Päivi; Minkkinen, Kari; Pennanen, Taina; Penttilä, Timo; Sarjala, Tytti; Tuittila, Eeva-Stiina; Tuomivirta, Tero; Fritze, Hannu

2015-07-01

Impacts of warming with open-top chambers on microbial communities in wet conditions and in conditions resulting from moderate water-level drawdown (WLD) were studied across 0-50 cm depth in northern and southern boreal sedge fens. Warming alone decreased microbial biomass especially in the northern fen. Impact of warming on microbial PLFA and fungal ITS composition was more obvious in the northern fen and linked to moisture regime and sample depth. Fungal-specific PLFA increased in the surface peat in the drier regime and decreased in layers below 10 cm in the wet regime after warming. OTUs representing Tomentella and Lactarius were observed in drier regime and Mortierella in wet regime after warming in the northern fen. The ectomycorrhizal fungi responded only to WLD. Interestingly, warming together with WLD decreased archaeal 16S rRNA copy numbers in general, and fungal ITS copy numbers in the northern fen. Expectedly, many results indicated that microbial response on warming may be linked to the moisture regime. Results indicated that microbial community in the northern fen representing Arctic soils would be more sensitive to environmental changes. The response to future climate change clearly may vary even within a habitat type, exemplified here by boreal sedge fen. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Effects of forest conversion on soil microbial communities depend on soil layer on the eastern Tibetan Plateau of China

PubMed Central

He, Ruoyang; Yang, Kaijun; Li, Zhijie; Schädler, Martin; Yang, Wanqin; Wu, Fuzhong; Tan, Bo; Zhang, Li

2017-01-01

Forest land-use changes have long been suggested to profoundly affect soil microbial communities. However, how forest type conversion influences soil microbial properties remains unclear in Tibetan boreal forests. The aim of this study was to explore variations of soil microbial profiles in the surface organic layer and subsurface mineral soil among three contrasting forests (natural coniferous forest, NF; secondary birch forest, SF and spruce plantation, PT). Soil microbial biomass, activity and community structure of the two layers were investigated by chloroform fumigation, substrate respiration and phospholipid fatty acid analysis (PLFA), respectively. In the organic layer, both NF and SF exhibited higher soil nutrient levels (carbon, nitrogen and phosphorus), microbial biomass carbon and nitrogen, microbial respiration, PLFA contents as compared to PT. However, the measured parameters in the mineral soils often did not differ following forest type conversion. Irrespective of forest types, the microbial indexes generally were greater in the organic layer than in the mineral soil. PLFAs biomarkers were significantly correlated with soil substrate pools. Taken together, forest land-use change remarkably altered microbial community in the organic layer but often did not affect them in the mineral soil. The microbial responses to forest land-use change depend on soil layer, with organic horizons being more sensitive to forest conversion. PMID:28982191

Microbial weathering of apatite and wollastonite in a forest soil: Evidence from minerals buried in a root-free zone

NASA Astrophysics Data System (ADS)

Nezat, C. A.

2011-12-01

Mineral weathering is an important process in biogeochemical cycling because it releases nutrients from less labile pools (e.g., rocks) to the food chain. A field experiment was undertaken to determine the degree to which microbes - both fungi and bacteria - are responsible for weathering of Ca-bearing minerals. The experiment was performed at the Hubbard Brook Experimental Forest (HBEF) in the northeastern USA, where acid deposition has leached plant-available calcium from soils for decades. Trees obtain soil nutrients through root uptake as well as through mycorrhizal fungi with which they are symbiotically associated. These fungi extend their hyphae from the tree roots into the soil and exude organic acids that may enhance mineral dissolution. The two most common types of symbiotic fungal-tree associations are ectomycorrhizae, which are associated with spruce (Picea), fir (Abies), and beech (Fagus); and arbuscular mycorrhizae which are commonly associated with angiosperms, such as maples (Acer). To examine the role of fungi and bacteria in weathering of Ca- and/or P-bearing minerals, mesh bags containing sand-sized grains of quartz (as a control), quartz plus 1% wollastonite (CaSiO3), or quartz plus 1% apatite (Ca5(PO4)3F) were buried ~15 cm deep in mineral soil beneath American beech, sugar maple, and mixed spruce and balsam fir stands at the HBEF. Half of the bags were constructed of 50-μm mesh to exclude roots but allow fungal hyphae and bacteria to enter the bags; the remaining bags had 1-μm mesh to exclude fungi and roots but allow bacteria to enter. The bags were retrieved ~ 1, 2 or 4 years after burial. Microbial community composition and biomass in the mesh bags and surrounding soil were characterized and quantified using phospholipid fatty acid (PLFA) analysis. Fungal biomass in the soil and control bags did not differ significantly among stand types. In contrast, the degree of fungal colonization in apatite- and wollastonite-amended bags varied significantly, suggesting that microbial response was due to tree species, type of mycorrhizal fungi, nutrient status of the soils, and mineral composition of the mesh bags. Mineral surfaces were examined using scanning electron microscopy (SEM) to investigate the degree of mineral dissolution as a function of stand type, microbial composition, and time.

Effects of Plant Functional Group Loss on Soil Microbial Community and Litter Decomposition in a Steppe Vegetation.

PubMed

Xiao, Chunwang; Zhou, Yong; Su, Jiaqi; Yang, Fan

2017-01-01

Globally, many terrestrial ecosystems are experiencing a rapid loss of biodiversity. Continued improvements in our understanding of interrelationships between plant diversity and soil microbes are critical to address the concern over the consequences of the decline in biodiversity on ecosystem functioning and services. By removing forbs, or grasses, or, to an extreme scenario, both forbs and grasses in a steppe vegetation in Inner Mongolia, we studied how plant functional group (PFG) loss affects soil microbial community composition using phospholipid fatty acid analysis (PLFA) and litter decomposition using a litter-bag method. PFG loss significantly decreased above- and below-ground plant biomass, soil microbial biomass carbon (SMBC) and nitrogen (SMBN), but had no effect on the ratio of SMBC to SMBN. Although the ratio of fungal to bacterial PLFAs remained unaffected, PFG loss significantly reduced the amount of bacterial, fungal, and total PLFAs. PFG loss decreased litter monthly mass loss and decay constant, and such decrease was significant when both forbs and grasses were removed. Our results provide robust evidence that PFG loss in grassland ecosystem can lead to a rapid response of soil microbial activity which may affect litter decomposition and soil nutrient cycling, suggesting that the assessment of plant-microbe interactions in soils is an integral component of ecosystem response to biodiversity loss.

Degradation of seed mucilage by soil microflora promotes early seedling growth of a desert sand dune plant.

PubMed

Yang, Xuejun; Baskin, Carol C; Baskin, Jerry M; Zhang, Wenhao; Huang, Zhenying

2012-05-01

In contrast to the extensive understanding of seed mucilage biosynthesis, much less is known about how mucilage is biodegraded and what role it plays in the soil where seeds germinate. We studied seed mucilage biodegradation by a natural microbial community. High-performance anion-exchange chromatography (HPAEC) was used to determine monosaccharide composition in achene mucilage of Artemisia sphaerocephala. Mucilage degradation by the soil microbial community from natural habitats was examined by monosaccharide utilization tests using Biolog plates, chemical assays and phospholipid fatty acid (PLFA) analysis. Glucose (29.4%), mannose (20.3%) and arabinose (19.5%) were found to be the main components of achene mucilage. The mucilage was biodegraded to CO(2) and soluble sugars, and an increase in soil microbial biomass was observed during biodegradation. Fluorescence microscopy showed the presence of mucilage (or its derivatives) in seedling tissues after growth with fluorescein isothiocyanate (FITC)-labelled mucilage. The biodegradation also promoted early seedling growth in barren sand dunes, which was associated with a large soil microbial community that supplies substances promoting seedling establishment. We conclude that biodegradation of seed mucilage can play an ecologically important role in the life cycles of plants especially in harsh desert environments to which A. sphaerocephala is well-adapted. © 2011 Blackwell Publishing Ltd.

Flooding forested groundwater recharge areas modifies microbial communities from top soil to groundwater table.

PubMed

Schütz, Kirsten; Nagel, Peter; Vetter, Walter; Kandeler, Ellen; Ruess, Liliane

2009-01-01

Subsurface microorganisms are crucial for contaminant degradation and maintenance of groundwater quality. This study investigates the microbial biomass and community composition [by phospholipid fatty acids (PLFAs)], as well as physical and chemical soil characteristics at woodland flooding sites of an artificial groundwater recharge system used for drinking water production. Vertical soil profiles to c. 4 m at two watered and one nonwatered site were analyzed. The microbial biomass was equal in watered and nonwatered sites, and considerable fractions (25-42%) were located in 40-340 cm depth. The microbial community structure differed significantly between watered and nonwatered sites, predominantly below 100 cm depth. Proportions of the bacterial PLFAs 16:1omega5, 16:1omega7, cy17:0 and 18:1omega9t, and the long-chained PLFAs 22:1omega9 and 24:1omega9 were more prominent at the watered sites, whereas branched, saturated PLFAs (iso/anteiso) dominated at the nonwatered site. PLFA community indices indicated stress response (trans/cis ratio), higher nutrient availability (unsaturation index) and changes in membrane fluidity (iso/anteiso ratio) due to flooding. In conclusion, water recharge processes led to nutrient input and altered environmental conditions, which resulted in a highly active and adapted microbial community residing in the vadose zone that effectively degraded organic compounds.

Investigating Freshwater Periphyton Community Response to Uranium with Phospholipid Fatty Acid and Denaturing Gradient Gel Electrophoresis Analyses

DOE Office of Scientific and Technical Information (OSTI.GOV)

Small, Jack A.; Bunn, Amoret L.; McKinstry, Craig A.

2008-04-01

Periphyton communities can be used as monitors of ecosystem health and as indicators of contamination in lotic systems. Measures of biomass, community structure and genetic diversity were used to investigate impacts of uranium exposure on periphyton. Laboratory exposures of periphyton in river water amended with uranium were performed for 5 days, followed by 2 days of uranium depuration in unamended river water. Productivity as measured by biomass was not affected by concentrations up to 100 µg L-1 uranium. Phospholipid fatty acid (PLFA) profiles and denaturing gradient gel electrophoresis (DGGE) banding patterns found no changes in community or genetic structure relatedmore » to uranium exposure. We suggest that the periphyton community as a whole is not impacted by exposures of uranium up to a dose of 100 µg L-1. These findings have significance for the assessment and prediction of uranium impacts on aquatic ecosystems.« less

The microbial communities and potential greenhouse gas production in boreal acid sulphate, non-acid sulphate, and reedy sulphidic soils.

PubMed

Šimek, Miloslav; Virtanen, Seija; Simojoki, Asko; Chroňáková, Alica; Elhottová, Dana; Krištůfek, Václav; Yli-Halla, Markku

2014-01-01

Acid sulphate (AS) soils along the Baltic coasts contain significant amounts of organic carbon and nitrogen in their subsoils. The abundance, composition, and activity of microbial communities throughout the AS soil profile were analysed. The data from a drained AS soil were compared with those from a drained non-AS soil and a pristine wetland soil from the same region. Moreover, the potential production of methane, carbon dioxide, and nitrous oxide from the soils was determined under laboratory conditions. Direct microscopic counting, glucose-induced respiration (GIR), whole cell hybridisation, and extended phospholipid fatty acid (PLFA) analysis confirmed the presence of abundant microbial communities in the topsoil and also in the deepest Cg2 horizon of the AS soil. The patterns of microbial counts, biomass and activity in the profile of the AS soil and partly also in the non-AS soil therefore differed from the general tendency of gradual decreases in soil profiles. High respiration in the deepest Cg2 horizon of the AS soil (5.66 μg Cg(-1)h(-1), as compared to 2.71 μg Cg(-1)h(-1) in a top Ap horizon) is unusual but reasonable given the large amount of organic carbon in this horizon. Nitrous oxide production peaked in the BCgc horizon of the AS and in the BC horizon of the non-AS soil, but the peak value was ten-fold higher in the AS soil than in the non-AS soil (82.3 vs. 8.6 ng Ng(-1)d(-1)). The data suggest that boreal AS soils on the Baltic coast contain high microbial abundance and activity. This, together with the abundant carbon and total and mineral nitrogen in the deep layers of AS soils, may result in substantial gas production. Consequently, high GHG emissions could occur, for example, when the generally high water table is lowered because of arable farming. © 2013.

Microbial activities related to C and N cycling and microbial community structure in the rhizospheres of Pinus sylvestris, Picea abies and Betula pendula seedlings in an organic and mineral soil.

PubMed

Priha; Grayston; Pennanen; Smolander

1999-10-01

The aim of this study was to determine whether Scots pine (Pinus sylvestris L.), Norway spruce (Picea abies (L.) Karst.) and silver birch (Betula pendula Roth) seedlings have a selective influence on the soil microbial community structure and activity and whether this varies in different soils. Seedlings of pine, spruce and birch were planted into pots of two soil types: an organic soil and a mineral soil. Pots without seedlings were also included. After one growing season, microbial biomass C (C(mic)) and N (N(mic)), C mineralization, net ammonification, net nitrification, denitrification potential, phospholipid fatty acid (PLFA) patterns and community level physiological profiles (CLPPs) were measured in the rhizosphere soil of the seedlings. In the organic soil, C(mic) and N(mic) were higher in the birch rhizosphere than in pine and spruce rhizosphere. The C mineralization rate was not affected by tree species. Unplanted soil contained the highest amount of mineral N and birch rhizosphere the lowest, but rates of net N mineralization and net nitrification did not differ between treatments. The microbial community structure, measured by PLFAs, had changed in the rhizospheres of all tree species compared to the unplanted soil. Birch rhizosphere was most clearly separated from the others. There was more of the fungal specific fatty acid 18:2omega6,9 and more branched fatty acids, common in Gram-positive bacteria, in this soil. CLPPs, done with Biolog GN plates and 30 additional substrates, separated only birch rhizosphere from the others. In the mineral soil, roots of all tree species stimulated C mineralization in soil and prevented nitrification, but did not affect C(mic) and N(mic), PLFA patterns or CLPPs. The effects of different tree species did not vary in the mineral soil. Thus, in the mineral soil, the strongest effect on soil microbes was the presence of a plant, regardless of the tree species, but in the organic soil, different tree species varied in their influence on soil microbes.

Assessment of Anaerobic Metabolic Activity and Microbial Diversity in a Petroleum-Contaminated Aquifer Using Push-Pull Tests in Combination With Molecular Tools and Stable Isotopes

NASA Astrophysics Data System (ADS)

Schroth, M. H.; Kleikemper, J.; Pombo, S. A.; Zeyer, J.

2002-12-01

In the past, studies on microbial communities in natural environments have typically focused on either their structure or on their metabolic function. However, linking structure and function is important for understanding microbial community dynamics, in particular in contaminated environments. We will present results of a novel combination of a hydrogeological field method (push-pull tests) with molecular tools and stable isotope analysis, which was employed to quantify anaerobic activities and associated microbial diversity in a petroleum-contaminated aquifer in Studen, Switzerland. Push-pull tests consisted of the injection of test solution containing a conservative tracer and reactants (electron acceptors, 13C-labeled carbon sources) into the aquifer anoxic zone. Following an incubation period, the test solution/groundwater mixture was extracted from the same location. Metabolic activities were computed from solute concentrations measured during extraction. Simultaneously, microbial diversity in sediment and groundwater was characterized by using fluorescence in situ hybridization (FISH), denaturing gradient gel electrophoresis (DGGE), as well as phospholipids fatty acid (PLFA) analysis in combination with 13C isotopic measurements. Results from DGGE analyses provided information on the general community structure before, during and after the tests, while FISH yielded information on active populations. Moreover, using 13C-labeling of microbial PLFA we were able to directly link carbon source assimilation in an aquifer to indigenous microorganisms while providing quantitative information on respective carbon source consumption.

Functional diversity of microbial communities in pristine aquifers inferred by PLFA- and sequencing-based approaches

NASA Astrophysics Data System (ADS)

Schwab, Valérie F.; Herrmann, Martina; Roth, Vanessa-Nina; Gleixner, Gerd; Lehmann, Robert; Pohnert, Georg; Trumbore, Susan; Küsel, Kirsten; Totsche, Kai U.

2017-05-01

Microorganisms in groundwater play an important role in aquifer biogeochemical cycles and water quality. However, the mechanisms linking the functional diversity of microbial populations and the groundwater physico-chemistry are still not well understood due to the complexity of interactions between surface and subsurface. Within the framework of Hainich (north-western Thuringia, central Germany) Critical Zone Exploratory of the Collaborative Research Centre AquaDiva, we used the relative abundances of phospholipid-derived fatty acids (PLFAs) to link specific biochemical markers within the microbial communities to the spatio-temporal changes of the groundwater physico-chemistry. The functional diversities of the microbial communities were mainly correlated with groundwater chemistry, including dissolved O2, Fet and NH4+ concentrations. Abundances of PLFAs derived from eukaryotes and potential nitrite-oxidizing bacteria (11Me16:0 as biomarker for Nitrospira moscoviensis) were high at sites with elevated O2 concentration where groundwater recharge supplies bioavailable substrates. In anoxic groundwaters more rich in Fet, PLFAs abundant in sulfate-reducing bacteria (SRB), iron-reducing bacteria and fungi increased with Fet and HCO3- concentrations, suggesting the occurrence of active iron reduction and the possible role of fungi in meditating iron solubilization and transport in those aquifer domains. In more NH4+-rich anoxic groundwaters, anammox bacteria and SRB-derived PLFAs increased with NH4+ concentration, further evidencing the dependence of the anammox process on ammonium concentration and potential links between SRB and anammox bacteria. Additional support of the PLFA-based bacterial communities was found in DNA- and RNA-based Illumina MiSeq amplicon sequencing of bacterial 16S rRNA genes, which showed high predominance of nitrite-oxidizing bacteria Nitrospira, e.g. Nitrospira moscoviensis, in oxic aquifer zones and of anammox bacteria in more NH4+-rich anoxic groundwater. Higher relative abundances of sequence reads in the RNA-based datasets affiliated with iron-reducing bacteria in more Fet-rich groundwater supported the occurrence of active dissimilatory iron reduction. The functional diversity of the microbial communities in the biogeochemically distinct groundwater assemblages can be largely attributed to the redox conditions linked to changes in bioavailable substrates and input of substrates with the seepage. Our results demonstrate the power of complementary information derived from PLFA-based and sequencing-based approaches.

Physiological and Proteomic Adaptation of “Aromatoleum aromaticum” EbN1 to Low Growth Rates in Benzoate-Limited, Anoxic Chemostats

PubMed Central

Trautwein, Kathleen; Lahme, Sven; Wöhlbrand, Lars; Feenders, Christoph; Mangelsdorf, Kai; Harder, Jens; Steinbüchel, Alexander; Blasius, Bernd; Reinhardt, Richard

2012-01-01

“Aromatoleum aromaticum” EbN1 was cultivated at different growth rates in benzoate-limited chemostats under nitrate-reducing conditions. Physiological characteristics, proteome dynamics, phospholipid-linked fatty acid (PLFA) composition, and poly(3-hydroxybutyrate) (PHB) content were analyzed in steady-state cells at low (μlow) (0.036 h−1), medium (μmed) (0.108 h−1), and high (μhigh) (0.180 h−1) growth rates. A positive correlation to growth rate was observed for cellular parameters (cell size, and DNA and protein contents). The free energy consumed for biomass formation steadily increased with growth rate. In contrast, the energy demand for maintenance increased only from μlow to μmed and then remained constant until μhigh. The most comprehensive proteomic changes were observed at μlow compared to μhigh. Uniformly decreased abundances of protein components of the anaerobic benzoyl coenzyme A (benzoyl-CoA) pathway, central carbon metabolism, and information processing agree with a general deceleration of benzoate metabolism and cellular processes in response to slow growth. In contrast, increased abundances were observed at μlow for diverse catabolic proteins and components of uptake systems in the absence of the respective substrate (aromatic or aliphatic compounds) and for proteins involved in stress responses. This potential catabolic versatility and stress defense during slow growth may be interpreted as preparation for future needs. PMID:22366417

Potential autotrophic metabolisms in ultra-basic reducing springs associated with present-day continental serpentinization

NASA Astrophysics Data System (ADS)

Morrill, P. L.; Miles, S.; Kohl, L.; Kavanagh, H.; Ziegler, S. E.; Brazelton, W. J.; Schrenk, M. O.

2013-12-01

Ultra-basic reducing springs at continental sites of serpentinization act as windows into the biogeochemistry of this subsurface exothermic environment rich in H2 and CH4 gases. Biogeochemical carbon transformations in these systems are of interest because serpentinization creates conditions that are amenable to abiotic and biotic reduction of carbon. However, little is known about the metabolic capabilities of the microorganisms that live in this environment. To determine the potential for autotrophic metabolisms, bicarbonate and CO substrate addition microcosm experiments were performed using water and sediment from an ultra-basic reducing spring in the Tablelands, Newfoundland, Canada, a site of present-day continental serpentinization. CO was consistently observed to be utilized in the Live but not the Killed controlled replicates amended with 10% 13C labelled CO and non-labelled (natural C isotope abundance) CO. In the Live CO microcosms with natural C isotope abundance, the residual CO became enriched in 13C (~10 ‰) consistent with a decrease in the fraction of CO remaining. In the Killed CO controlled replicates with natural C isotope abundance the CO showed little 13C enrichment (~1.3 ‰). The data from the Live CO microcosms were well described by a Rayleigh isotopic distillation model, yielding an isotopic enrichment factor for microbial CO uptake of 15.7 ×0.5 ‰ n=2. These data suggest that there was microbial CO utilization in these experiments. The sediment and water from the 13C-labelled and non-labelled, Live and Killed microcosms were extracted for phospholipid fatty acids (PLFAs) to determine changes in community composition between treatments as well as to determine the microbial uptake of CO. The difference in community composition between the Live and Killed microcosms was not readily resolvable based on PLFA distributions. Additionally, the microbial uptake of 13CO had minimal to no affect on the δ13C of the cellular biomarkers, with the exception of C16 saturated and a C16 monounsaturated PLFAs in one live microcosm which showed >2 ‰ and >10 ‰ enrichment, respectively, compared to the average δ13C values of the same PLFA in the 13C Killed controlled replicates. Therefore the uptake of CO had minimal effect on the overall biomass and community composition in the system. The 13C labelled bicarbonate anaerobic microcosm experiments showed little to no methane production. The methane detected in the 13C labelled Live experiments were not isotopically enriched in 13C compared to the CH4 in the labelled Killed controlled replicates. Therefore bicarbonate was not used as a substrate for microbial methanogenesis via the CO2 reduction pathway. These results are generally consistent with genomic and metagenomic data, which discovered the potential for a carbon fixation pathway involving carbon monoxide, but little evidence for archaea or methanogenesis in the ultra-basic springs in the Tablelands (Brazelton et al., 2012). Reference: Brazelton WJ, Nelson B, & Schrenk MO (2012) Frontiers in Microbiology 2:1-16.

Contrasting responses of bacterial and fungal communities to aggregate-size fractions and long-term fertilizations in soils of northeastern China.

PubMed

Liao, Hao; Zhang, Yuchen; Zuo, Qinyan; Du, Binbin; Chen, Wenli; Wei, Dan; Huang, Qiaoyun

2018-04-20

Soils, with non-uniform distribution of nutrients across different aggregate-size fractions, provide spatially heterogeneous microhabitats for microorganisms. However, very limited information is available on microbial distributions and their response to fertilizations across aggregate-size fractions in agricultural soils. Here, we examined the structures of bacterial and fungal communities across different aggregate-size fractions (2000-250 μm, 250-53 μm and <53 μm) in response to 35-years organic and/or chemical fertilization regimes in the soil of northeastern China by phospholipid fatty acid (PLFA) and high throughput sequencing (HTS) technology. Our results show that larger fractions (>53 μm), especially 250-53 μm aggregates, which contain more soil C and N, are associated with greater microbial biomass and higher fungi/bacteria ratio. We firstly reported the fungal community composition in different aggregate-size fractions by HTS technology and found more Ascomycota but less Zygomycota in larger fractions with higher C content across all fertilization regimes. Fertilization and aggregate-size fractions significantly affect the compositions of bacterial and fungal communities although their effects are different. The bacterial community is mainly driven by fertilization, especially chemical fertilizers, and is closely related to the shifts of soil P (phosphorus). The fungal community is preferentially impacted by different aggregate-size fractions and is more associated with the changes of soil C and N. The distinct responses of microbial communities suggest different mechanisms controlling the assembly of soil bacterial and fungal communities at aggregate scale. The investigations of both bacterial and fungal communities could provide a better understanding on nutrient cycling across aggregate-size fractions. Copyright © 2018. Published by Elsevier B.V.

Biotic and Abiotic Properties Mediating Plant Diversity Effects on Soil Microbial Communities in an Experimental Grassland

PubMed Central

Lange, Markus; Habekost, Maike; Eisenhauer, Nico; Roscher, Christiane; Bessler, Holger; Engels, Christof; Oelmann, Yvonne; Scheu, Stefan; Wilcke, Wolfgang; Schulze, Ernst-Detlef; Gleixner, Gerd

2014-01-01

Plant diversity drives changes in the soil microbial community which may result in alterations in ecosystem functions. However, the governing factors between the composition of soil microbial communities and plant diversity are not well understood. We investigated the impact of plant diversity (plant species richness and functional group richness) and plant functional group identity on soil microbial biomass and soil microbial community structure in experimental grassland ecosystems. Total microbial biomass and community structure were determined by phospholipid fatty acid (PLFA) analysis. The diversity gradient covered 1, 2, 4, 8, 16 and 60 plant species and 1, 2, 3 and 4 plant functional groups (grasses, legumes, small herbs and tall herbs). In May 2007, soil samples were taken from experimental plots and from nearby fields and meadows. Beside soil texture, plant species richness was the main driver of soil microbial biomass. Structural equation modeling revealed that the positive plant diversity effect was mainly mediated by higher leaf area index resulting in higher soil moisture in the top soil layer. The fungal-to-bacterial biomass ratio was positively affected by plant functional group richness and negatively by the presence of legumes. Bacteria were more closely related to abiotic differences caused by plant diversity, while fungi were more affected by plant-derived organic matter inputs. We found diverse plant communities promoted faster transition of soil microbial communities typical for arable land towards grassland communities. Although some mechanisms underlying the plant diversity effect on soil microorganisms could be identified, future studies have to determine plant traits shaping soil microbial community structure. We suspect differences in root traits among different plant communities, such as root turnover rates and chemical composition of root exudates, to structure soil microbial communities. PMID:24816860

Degradation of organic pollutants by methane grown microbial consortia.

PubMed

Hesselsoe, Martin; Boysen, Susanne; Iversen, Niels; Jørgensen, Lars; Murrell, J Colin; McDonald, Ian; Radajewski, Stefan; Thestrup, Helle; Roslev, Peter

2005-10-01

Microbial consortia were enriched from various environmental samples with methane as the sole carbon and energy source. Selected consortia that showed a capacity for co-oxidation of naphthalene were screened for their ability to degrade methyl-tert-butyl-ether (MTBE), phthalic acid esters (PAE), benzene, xylene and toluene (BTX). MTBE was not removed within 24 h by any of the consortia examined. One consortium enriched from activated sludge ("AAE-A2"), degraded PAE, including (butyl-benzyl)phthalate (BBP), and di-(butyl)phthalate (DBP). PAE have not previously been described as substrates for methanotrophic consortia. The apparent Km and Vmax for DBP degradation by AAE-A2 at 20 degrees C was 3.1 +/- 1.2 mg l(-1) and 8.7 +/- 1.1 mg DBP (g protein x h)(-1), respectively. AAE-A2 also showed fast degradation of BTX (230 +/- 30 nmol benzene (mg protein x h)(-1) at 20 degrees C). Additionally, AAE-A2 degraded benzene continuously for 2 weeks. In contrast, a pure culture of the methanotroph Methylosinus trichosporium OB3b ceased benzene degradation after only 2 days. Experiments with methane mono-oxygenase inhibitors or competitive substrates suggested that BTX degradation was carried out by methane-oxidizing bacteria in the consortium, whereas the degradation of PAE was carried out by non-methanotrophic bacteria co-existing with methanotrophs. The composition of the consortium (AAE-A2) based on polar lipid fatty acid (PLFA) profiles showed dominance of type II methanotrophs (83-92% of biomass). Phylogeny based on a 16S-rRNA gene clone library revealed that the dominating methanotrophs belonged to Methylosinus/Methylocystis spp. and that members of at least 4 different non-methanotrophic genera were present (Pseudomonas, Flavobacterium, Janthinobacterium and Rubivivax).

Dissipation of sulfamethoxazole in pasture soils as affected by soil and environmental factors.

PubMed

Srinivasan, Prakash; Sarmah, Ajit K

2014-05-01

The dissipation of sulfamethoxazole (SMO) antibiotic in three different soils was investigated through laboratory incubation studies. The experiments were conducted under different incubation conditions such as initial chemical concentration, soil depth, temperature, and with sterilisation. The results indicate that SMO dissipated rapidly in New Zealand pasture soils, and the 50% dissipation times (DT50) in Hamilton, Te Kowhai and Horotiu soils under non-sterile conditions were 9.24, 4.3 and 13.33 days respectively. During the incubation period for each sampling event the soil dehydrogenase activity (DHA) and the variation in microbial community were monitored thorough phospholipid fatty acid extraction analysis (PLFA). The DHA data correlated well with the dissipation rate constants of SMO antibiotic, an increase in the DHA activity resulted in faster antibiotic dissipation. The PLFA analysis was indicative of higher bacterial presence as compared to fungal community, highlighting the type of microbial community responsible for dissipation. The results indicate that with increasing soil depth, SMO dissipation in soil was slower (except for Horotiu) while with increase in temperature the antibiotic loss was faster, and was noticeable in all the soils. Both the degree of biological activity and the temperature of the soil influenced overall SMO dissipation. SMO is not likely to persist more than 5-6 months in all three soils suggesting that natural biodegradation may be sufficient for the removal of these contaminants from the soil. Its dissipation in sterile soils indicated abiotic factors such as strong sorption onto soil components to play a role in the dissipation of SMO. Copyright © 2014 Elsevier B.V. All rights reserved.

Non-target impact of fungicide tetraconazole on microbial communities in soils with different agricultural management.

PubMed

Sułowicz, Sławomir; Cycoń, Mariusz; Piotrowska-Seget, Zofia

2016-08-01

Effect of the fungicide tetraconazole on microbial community in silt loam soils from orchard with long history of triazole application and from grassland with no known history of fungicide usage was investigated. Triazole tetraconazole that had never been used on these soils before was applied at the field rate and at tenfold the FR. Response of microbial communities to tetraconazole was investigated during 28-day laboratory experiment by determination of changes in their biomass and structure (phospholipid fatty acids method-PLFA), activity (fluorescein diacetate hydrolysis-FDA) as well as changes in genetic (DGGE) and functional (Biolog) diversity. Obtained results indicated that the response of soil microorganisms to tetraconazole depended on the management of the soils. DGGE patterns revealed that both dosages of fungicide affected the structure of bacterial community and the impact on genetic diversity and richness was more prominent in orchard soil. Values of stress indices-the saturated/monounsaturated PLFAs ratio and the cyclo/monounsaturated precursors ratio, were almost twice as high and the Gram-negative/Gram-positive ratio was significantly lower in the orchard soil compared with the grassland soil. Results of principal component analysis of PLFA and Biolog profiles revealed significant impact of tetraconazole in orchard soil on day 28, whereas changes in these profiles obtained for grassland soil were insignificant or transient. Obtained results indicated that orchards soil seems to be more vulnerable to tetraconazole application compared to grassland soil. History of pesticide application and agricultural management should be taken into account in assessing of environmental impact of studied pesticides.

[Effects of litter and root exclusion on soil microbial community composition and function of four plantations in subtropical sandy coastal plain area, China].

PubMed

Sang, Chang Peng; Wan, Xiao Hua; Yu, Zai Peng; Wang, Min Huang; Lin, Yu; Huang, Zhi Qun

2017-04-18

We conducted detritus input and removal treatment (DIRT) to examine the effects of shifting above- and belowground carbon (C) inputs on soil microbial biomass, community composition and function in subtropical Pinus elliottii, Eucalyptus urophylla × Eucalyptus grandis, Acacia aulacocarpa and Casuarina equisetifolia coastal sandy plain forests, and the treatments included: root trenching, litter removal and control. Up to September 2015, one year after the experiment began, we collected the 0-10 cm soil samples from each plot. Phospholipid fatty acid (PLFA) analysis was used to characterize the microbial community composition, and micro-hole enzymatic detection technology was utilized to determine the activity of six kinds of soil enzymes. Results showed that changes in microbial biomass induced by the C input manipulations differed among tree species, and mainly affected by litter and root qualily. In E. urophylla × E. grandis stands, root trenching significantly decreased the contents of total PLFAs, Gram-positive bacteria, Gram-negative bacteria, fungi and actinomycetes by 31%, 30%, 32%, 36% and 26%, respectively. Litter removal reduced the contents of Gram-positive bacteria, fungi and actinomycetes by 24%, 27% and 24%, respectively. However, C input manipulations had no significant effect on soil microbial biomassunder other three plantations. According to the effect of C input manipulations on soil microbial community structure, litter and root exclusion decreased fungi abundance and increased actinomycetes abundance. Different treatments under different plantations resulted in various soil enzyme activities. Litter removal significantly decreased the activities of cellobiohydrolase, β-glucosidase, acid phosphatase and N-acetyl-β-d-glucosaminidase of P. elliottii, A. aulacocarpa and C. equisetifolia, root exclusion only decreased and increased the activities of β-glucosidase in P. elliottii and A. aulacocarpa forest soils, respectively. Litter removal also decreased the activities of polyphenol oxidase (PPO) and peroxidase (PER) in P. elliottii and C. equisetifolia forest soils, while root trenching had no significant effect on the activities of PPO and PER under all plantations. The properties of litter and root were the important factors in determining the soil microbial community and enzyme activity, and the change of soil microenvironment, such as temperature and moisture, caused by C input manipulations was also the important driver for the change of soil microbial property.

Linking Microbial and Biogeochemical Studies: Biological Controls of Methane Release from an Acidic Natural Wetland in Central Pennsylvania

NASA Astrophysics Data System (ADS)

Biddle, J. F.; Turich, C.; Brantley, S.; Bruns, M.

2002-12-01

Wetlands produce between 55 and 150 Tg of methane per year, or ~70% of all natural methane, and 20% of total methane (natural and anthropogenic). Understanding inputs to the global methane cycle depends on integrated in situ study of the sources and sinks of methane, as well as the rate and magnitude of methane production and consumption. Bear Meadows Natural Area in central Pennsylvania (N 40° 43.796' W 077° 45.310; 554 m elevation) contains an acidic, methane-producing, peaty bog with vegetation that is typical of wetlands at higher latitudes. In this four year study conducted within a cross-disciplinary training course offered by the NSF-IGERT Biogeochemical Research Initiative in Education (BRIE) program at Penn State University, graduate students applied a combination of geochemical and microbiological techniques to explore microbial diversity and activity in Bear Meadows sediments. The methane flux at the peat:water interface was highly variable, from 0.01 to over 3000 umol/m2/min in both sphagnum and sedge vegetation. The methane released from the bog had a carbon isotopic composition of -60 %o, typical of biogenic methane. Analysis of peat pore waters showed that the most methane was produced 30 cm below the peat:water interface, with a broad peak of methane in pore waters from 20-40 cm. At 21 cm below the peat:water interface, profiles of Archaeal 16S-23S ribosomal RNA spacer regions revealed the presence of populations having 92% similarity to 16S rRNA sequences of Methanoculleus marisnigri. Phospholipid fatty acids (PLFA) and compound specific isotope analysis revealed other biological controls on the methane cycle. PLFAs typical of methanotrophic bacteria were also present within peat cores from 20-30 cm below the water interface. The depleted carbon isotopic composition of these biomarkers (C16:1 and C18:1 fatty acids) was - 31.4 %o and - 33.8%o, indicative of methane oxidation. The presence of biomarkers of methane oxidizing bacteria within the zone of methane production may indicate that there is temporal or spatial heterogeneity in oxygen concentration within the peat. This interdisciplinary approach helped define specific ecological niches where novel methanogens and methane oxidizers may be active in a typical northern wetland. Through BRIE, on-going studies of the Bear Meadows wetland will focus on detecting other potentially novel aerobic and anaerobic microbes, and determining the biological influence on methane release to the atmosphere.

Stable-isotope-based labeling of styrene-degrading microorganisms in biofilters.

PubMed

Alexandrino, M; Knief, C; Lipski, A

2001-10-01

Deuterated styrene ([(2)H(8)]styrene) was used as a tracer in combination with phospholipid fatty acid (PLFA) analysis for characterization of styrene-degrading microbial populations of biofilters used for treatment of waste gases. Deuterated fatty acids were detected and quantified by gas chromatography-mass spectrometry. The method was evaluated with pure cultures of styrene-degrading bacteria and defined mixed cultures of styrene degraders and non-styrene-degrading organisms. Incubation of styrene degraders for 3 days with [(2)H(8)]styrene led to fatty acids consisting of up to 90% deuterated molecules. Mixed-culture experiments showed that specific labeling of styrene-degrading strains and only weak labeling of fatty acids of non-styrene-degrading organisms occurred after incubation with [(2)H(8)]styrene for up to 7 days. Analysis of actively degrading filter material from an experimental biofilter and a full-scale biofilter by this method showed that there were differences in the patterns of labeled fatty acids. For the experimental biofilter the fatty acids with largest amounts of labeled molecules were palmitic acid (16:0), 9,10-methylenehexadecanoic acid (17:0 cyclo9-10), and vaccenic acid (18:1 cis11). These lipid markers indicated that styrene was degraded by organisms with a Pseudomonas-like fatty acid profile. In contrast, the most intensively labeled fatty acids of the full-scale biofilter sample were palmitic acid and cis-11-hexadecenoic acid (16:1 cis11), indicating that an unknown styrene-degrading taxon was present. Iso-, anteiso-, and 10-methyl-branched fatty acids showed no or weak labeling. Therefore, we found no indication that styrene was degraded by organisms with methyl-branched fatty fatty acids, such as Xanthomonas, Bacillus, Streptomyces, or Gordonia spp.

Recovery of microbial community structure and functioning after wildfire in semi-arid environments: optimising methods for monitoring and assessment

NASA Astrophysics Data System (ADS)

Muñoz-Rojas, Miriam; Martini, Dylan; Erickson, Todd; Merritt, David; Dixon, Kingsley

2015-04-01

Introduction In semi-arid areas such as northern Western Australia, wildfires are a natural part of the environment and many ecosystems in these landscapes have evolved and developed a strong relationship with fire. Soil microbial communities play a crucial role in ecosystem processes by regulating the cycling of nutrients via decomposition, mineralization, and immobilization processes. Thus, the structure (e.g. soil microbial biomass) and functioning (e.g. soil microbial activity) of microbial communities, as well as their changes after ecosystem disturbance, can be useful indicators of soil quality and health recovery. In this research, we assess the impacts of fire on soil microbial communities and their recovery in a biodiverse semi-arid environment of Western Australia (Pilbara region). New methods for determining soil microbial respiration as an indicator of microbial activity and soil health are also tested. Methodology Soil samples were collected from 10 similar ecosystems in the Pilbara with analogous native vegetation, but differing levels of post-fire disturbance (i.e. 3 months, 1 year, 5, 7 and 14 years after wildfire). Soil microbial activity was measured with the Solvita test which determines soil microbial respiration rate based on the measurement of the CO2 burst of a dry soil after it is moistened. Soils were dried and re-wetted and a CO2 probe was inserted before incubation at constant conditions of 25°C during 24 h. Measurements were taken with a digital mini spectrometer. Microbial (bacteria and fungi) biomass and community composition were measured by phospholipid fatty acid analysis (PLFA). Results Immediately after the fire (i.e. 3 months), soil microbial activity and microbial biomass are similar to 14 years 'undisturbed' levels (53.18±3.68 ppm CO2-CO and 14.07±0.65 mg kg-1, respectively). However, after the first year post-fire, with larger plant productivity, microbial biomass and microbial activity increase rapidly, peaking after 5-7 years post fire (70.70±8.94 ppm CO2-CO and 21.67±2.62 mg kg-1, respectively). Microbial activity measured with the Solvita test was significantly correlated (R Pearson > 0.7; P < 0.001) with microbial parameters analysed with PLFA such as microbial biomass, bacteria biomass or mycorrhizhal fungi. This method has proven to be reliable, fast and easy to interpret for assessment of soil microbial activity in the recovery of soil quality during the recovery after fire. Keywords Pilbara region, biodiverse ecosystems, microbial biomass, microbial respiration, Solvita test, CO2 burst.

Land-use and soil depth affect resource and microbial stoichiometry in a tropical mountain rainforest region of southern Ecuador.

PubMed

Tischer, Alexander; Potthast, Karin; Hamer, Ute

2014-05-01

Global change phenomena, such as forest disturbance and land-use change, significantly affect elemental balances as well as the structure and function of terrestrial ecosystems. However, the importance of shifts in soil nutrient stoichiometry for the regulation of belowground biota and soil food webs have not been intensively studied for tropical ecosystems. In the present account, we examine the effects of land-use change and soil depth on soil and microbial stoichiometry along a land-use sequence (natural forest, pastures of different ages, secondary succession) in the tropical mountain rainforest region of southern Ecuador. Furthermore, we analyzed (PLFA-method) whether shifts in the microbial community structure were related to alterations in soil and microbial stoichiometry. Soil and microbial stoichiometry were affected by both land-use change and soil depth. After forest disturbance, significant decreases of soil C:N:P ratios at the pastures were followed by increases during secondary succession. Microbial C:N ratios varied slightly in response to land-use change, whereas no fixed microbial C:P and N:P ratios were observed. Shifts in microbial community composition were associated with soil and microbial stoichiometry. Strong positive relationships between PLFA-markers 18:2n6,9c (saprotrophic fungi) and 20:4 (animals) and negative associations between 20:4 and microbial N:P point to land-use change affecting the structure of soil food webs. Significant deviations from global soil and microbial C:N:P ratios indicated a major force of land-use change to alter stoichiometric relationships and to structure biological systems. Our results support the idea that soil biotic communities are stoichiometrically flexible in order to adapt to alterations in resource stoichiometry.

Microbial responses and nitrous oxide emissions during wetting and drying of organically and conventionally managed soil under tomatoes

USGS Publications Warehouse

Burger, M.; Jackson, L.E.; Lundquist, E.J.; Louie, D.T.; Miller, R.L.; Rolston, D.E.; Scow, K.M.

2005-01-01

The types and amounts of carbon (C) and nitrogen (N) inputs, as well as irrigation management are likely to influence gaseous emissions and microbial ecology of agricultural soil. Carbon dioxide (CO2) and nitrous oxide (N2O) efflux, with and without acetylene inhibition, inorganic N, and microbial biomass C were measured after irrigation or simulated rainfall in two agricultural fields under tomatoes (Lycopersicon esculentum). The two fields, located in the California Central Valley, had either a history of high organic matter (OM) inputs ("organic" management) or one of low OM and inorganic fertilizer inputs ("conventional" management). In microcosms, where short-term microbial responses to wetting and drying were studied, the highest CO2 efflux took place at about 60% water-filled pore space (WFPS). At this moisture level, phospholipid fatty acids (PLFA) indicative of microbial nutrient availability were elevated and a PLFA stress indicator was depressed, suggesting peak microbial activity. The highest N 2O efflux in the organically managed soil (0.94 mg N2O-N m-2 h-1) occurred after manure and legume cover crop incorporation, and in the conventionally managed soil (2.12 mg N2O-N m-2 h-1) after inorganic N fertilizer inputs. Elevated N2O emissions occurred at a WFPS >60% and lasted <2 days after wetting, probably because the top layer (0-150 mm) of this silt loam soil dried quickly. Therefore, in these cropping systems, irrigation management might control the duration of elevated N2O efflux, even when C and inorganic N availability are high, whereas inorganic N concentrations should be kept low during times when soil moisture cannot be controlled.

Microorganisms, Organic Carbon, and Their Relationship with Oxidant Activity in Hyper-Arid Mars-Like Soils: Implications for Soil Habitability

NASA Technical Reports Server (NTRS)

Valdivia-Silva, Julio E.; Karouia, Fathi; Navarro-Gonzalez, Rafael; McKay, Christopher

2016-01-01

Soil samples from the hyper-arid region in the Atacama 23 Desert in Southern Peru (La Joya Desert) were analyzed for total and labile organic carbon (TOC & LOC), phospholipid fatty acids analysis (PLFA), quantitative real time polymerase chain reaction (qRT-PCR), 4',6- diamidino-2-phenylindole (DAPI)-fluorescent microscopy, culturable microorganisms, and oxidant activity, in order to understand the relationship between the presence of organic matter and microorganisms in these types of soils. TOC content levels were similar to the labile pool of carbon suggesting the absence of recalcitrant carbon in these soils. The range of LOC was from 2 to 60 micro-g/g of soil. PLFA analysis indicated a maximum of 2.3 x 10(exp 5) cell equivalents/g. Culturing of soil extracts yielded 1.1 x 10(exp 2)-3.7 x 10(exp 3) CFU/g. qRT-PCR showed between 1.0 x 10(exp 2) and 8 x 10(exp 3) cells/g; and DAPI fluorescent staining indicated bacteria counts up to 5 x 104 cells/g. Arid and semiarid samples (controls) showed values between 10(exp 7) and 10(exp 11) cells/g with all of the methods used. Importantly, the concentration of microorganisms in hyper-arid soils did not show any correlation with the organic carbon content; however, there was a significant dependence on the oxidant activity present in these soil samples evaluated as the capacity to decompose sodium formate in 10 hours. We suggest that the analysis of oxidant activity could be a useful indicator of the microbial habitability in hyper-arid soils, obviating the need to measure water activity over time. This approach could be useful in astrobiological studies on other worlds.

Microbial food web dynamics along a soil chronosequence of a glacier forefield

NASA Astrophysics Data System (ADS)

Esperschütz, J.; Pérez-de-Mora, A.; Schreiner, K.; Welzl, G.; Buegger, F.; Zeyer, J.; Hagedorn, F.; Munch, J. C.; Schloter, M.

2011-11-01

Microbial food webs are critical for efficient nutrient turnover providing the basis for functional and stable ecosystems. However, the successional development of such microbial food webs and their role in "young" ecosystems is unclear. Due to a continuous glacier retreat since the middle of the 19th century, glacier forefields have expanded offering an excellent opportunity to study food web dynamics in soils at different developmental stages. In the present study, litter degradation and the corresponding C fluxes into microbial communities were investigated along the forefield of the Damma glacier (Switzerland). 13C-enriched litter of the pioneering plant Leucanthemopsis alpina (L.) Heywood was incorporated into the soil at sites that have been free from ice for approximately 10, 60, 100 and more than 700 years. The structure and function of microbial communities were identified by 13C analysis of phospholipid fatty acids (PLFA) and phospholipid ether lipids (PLEL). Results showed increasing microbial diversity and biomass, and enhanced proliferation of bacterial groups as ecosystem development progressed. Initially, litter decomposition proceeded faster at the more developed sites, but at the end of the experiment loss of litter mass was similar at all sites, once the more easily-degradable litter fraction was processed. As a result incorporation of 13C into microbial biomass was more evident during the first weeks of litter decomposition. 13C enrichments of both PLEL and PLFA biomarkers following litter incorporation were observed at all sites, suggesting similar microbial foodwebs at all stages of soil development. Nonetheless, the contribution of bacteria, especially actinomycetes to litter turnover became more pronounced as soil age increased in detriment of archaea, fungi and protozoa, more prominent in recently deglaciated terrain.

Importance of inoculum properties on the structure and growth of bacterial communities during Recolonisation of humus soil with different pH.

PubMed

Pettersson, Marie; Bååth, Erland

2013-08-01

The relationship between community structure and growth and pH tolerance of a soil bacterial community was studied after liming in a reciprocal inoculum study. An unlimed (UL) humus soil with a pH of 4.0 was fumigated with chloroform for 4 h, after which < 1 % of the initial bacterial activity remained. Half of the fumigated soil was experimentally limed (EL) to a pH of 7.6. Both the UL and the EL soil were then reciprocally inoculated with UL soil or field limed (FL) soil with a pH of 6.2. The FL soil was from a 15-year-old experiment. The structural changes were measured on both bacteria in soil and on bacteria able to grow on agar plates using phospholipids fatty acid (PLFA) and denaturing gradient gel electrophoresis (DGGE) analysis. The developing community pH tolerance and bacterial growth were also monitored over time using thymidine incorporation. The inoculum source had a significant impact on both growth and pH tolerance of the bacterial community in the EL soil. These differences between the EL soil inoculated with UL soil and FL soil were correlated to structural changes, as evidenced by both PLFA and DGGE analyses on the soil. Similar correlations were seen to the fraction of the community growing on agar plates. There were, however, no differences between the soil bacterial communities in the unlimed soils with different inocula. This study showed the connection between the development of function (growth), community properties (pH tolerance) and the structure of the bacterial community. It also highlighted the importance of both the initial properties of the community and the selection pressure after environmental changes in shaping the resulting microbial community.

Stimulation of Microbially Mediated Arsenic Release in Bangladesh Aquifers by Young Carbon Indicated by Radiocarbon Analysis of Sedimentary Bacterial Lipids.

PubMed

Whaley-Martin, K J; Mailloux, B J; van Geen, A; Bostick, B C; Silvern, R F; Kim, C; Ahmed, K M; Choudhury, I; Slater, G F

2016-07-19

The sources of reduced carbon driving the microbially mediated release of arsenic to shallow groundwater in Bangladesh remain poorly understood. Using radiocarbon analysis of phospholipid fatty acids (PLFAs) and potential carbon pools, the abundance and carbon sources of the active, sediment-associated, in situ bacterial communities inhabiting shallow aquifers (<30 m) at two sites in Araihazar, Bangladesh, were investigated. At both sites, sedimentary organic carbon (SOC) Δ(14)C signatures of -631 ± 54‰ (n = 12) were significantly depleted relative to dissolved inorganic carbon (DIC) of +24 ± 30‰ and dissolved organic carbon (DOC) of -230 ± 100‰. Sediment-associated PLFA Δ(14)C signatures (n = 10) at Site F (-167‰ to +20‰) and Site B (-163‰ to +21‰) were highly consistent and indicated utilization of carbon sources younger than the SOC, likely from the DOC pool. Sediment-associated PLFA Δ(14)C signatures were consistent with previously determined Δ(14)C signatures of microbial DNA sampled from groundwater at Site F indicating that the carbon source for these two components of the subsurface microbial community is consistent and is temporally stable over the two years between studies. These results demonstrate that the utilization of relatively young carbon sources by the subsurface microbial community occurs at sites with varying hydrology. Further they indicate that these young carbon sources drive the metabolism of the more abundant sediment-associated microbial communities that are presumably more capable of Fe reduction and associated release of As. This implies that an introduction of younger carbon to as of yet unaffected sediments (such as those comprising the deeper Pleistocene aquifer) could stimulate microbial communities and result in arsenic release.

Chitin Mixed in Potting Soil Alters Lettuce Growth, the Survival of Zoonotic Bacteria on the Leaves and Associated Rhizosphere Microbiology

PubMed Central

Debode, Jane; De Tender, Caroline; Soltaninejad, Saman; Van Malderghem, Cinzia; Haegeman, Annelies; Van der Linden, Inge; Cottyn, Bart; Heyndrickx, Marc; Maes, Martine

2016-01-01

Chitin is a promising soil amendment for improving soil quality, plant growth, and plant resilience. The objectives of this study were twofold. First, to study the effect of chitin mixed in potting soil on lettuce growth and on the survival of two zoonotic bacterial pathogens, Escherichia coli O157:H7 and Salmonella enterica on the lettuce leaves. Second, to assess the related changes in the microbial lettuce rhizosphere, using phospholipid fatty acid (PLFA) analysis and amplicon sequencing of a bacterial 16S rRNA gene fragment and the fungal ITS2. As a result of chitin addition, lettuce fresh yield weight was significantly increased. S. enterica survival in the lettuce phyllosphere was significantly reduced. The E. coli O157:H7 survival was also lowered, but not significantly. Moreover, significant changes were observed in the bacterial and fungal community of the lettuce rhizosphere. PLFA analysis showed a significant increase in fungal and bacterial biomass. Amplicon sequencing showed no increase in fungal and bacterial biodiversity, but relative abundances of the bacterial phyla Acidobacteria, Verrucomicrobia, Actinobacteria, Bacteroidetes, and Proteobacteria and the fungal phyla Ascomycota, Basidiomycota, and Zygomycota were significantly changed. More specifically, a more than 10-fold increase was observed for operational taxonomic units belonging to the bacterial genera Cellvibrio, Pedobacter, Dyadobacter, and Streptomyces and to the fungal genera Lecanicillium and Mortierella. These genera include several species previously reported to be involved in biocontrol, plant growth promotion, the nitrogen cycle and chitin degradation. These results enhance the understanding of the response of the rhizosphere microbiome to chitin amendment. Moreover, this is the first study to investigate the use of soil amendments to control the survival of S. enterica on plant leaves. PMID:27148242

DOE Office of Scientific and Technical Information (OSTI.GOV)

Techtmann, Stephen M.; Fortney, Julian L.; Ayers, Kati A.

The waters of the Eastern Mediterranean are characterized by unique physical and chemical properties within separate water masses occupying different depths. Distinct water masses are present throughout the oceans, which drive thermohaline circulation. These water masses may contain specific microbial assemblages. The goal of this study was to examine the effect of physical and geological phenomena on the microbial community of the Eastern Mediterranean water column. Chemical measurements were combined with phospholipid fatty acid (PLFA) analysis and high-throughput 16S rRNA sequencing to characterize the microbial community in the water column at five sites. We demonstrate that the chemistry and microbialmore » community of the water column were stratified into three distinct water masses. The salinity and nutrient concentrations vary between these water masses. Nutrient concentrations increased with depth, and salinity was highest in the intermediate water mass. Our PLFA analysis indicated different lipid classes were abundant in each water mass, suggesting that distinct groups of microbes inhabit these water masses. 16S rRNA gene sequencing confirmed the presence of distinct microbial communities in each water mass. Taxa involved in autotrophic nitrogen cycling were enriched in the intermediate water mass suggesting that microbes in this water mass may be important to the nitrogen cycle of the Eastern Mediterranean. The Eastern Mediterranean also contains numerous active hydrocarbon seeps. We sampled above the North Alex Mud Volcano, in order to test the effect of these geological features on the microbial community in the adjacent water column. The community in the waters overlaying the mud volcano was distinct from other communities collected at similar depths and was enriched in known hydrocarbon degrading taxa. Furthermore, our results demonstrate that physical phenomena such stratification as well as geological phenomena such as mud volcanoes strongly affect microbial community structure in the Eastern Mediterranean water column.« less

[Soil microbial community structure of monoculture and mixed plantation stands of native tree species in south subtropical China].

PubMed

Luo, Da; Shi, Zuo-Min; Tang, Jing-Chao; Liu, Shi-Rong; Lu, Li-Hua

2014-09-01

The effects of three plantation stands, Erythrophleumf ordii (EF), Pinus massoniana (PM), and their mixed plantation (MP), on soil microbial biomass and microbial community structure in south subtropical China were studied by the method of phospholipid fatty acids (PLFAs) analysis. The results showed that the amounts of microbial total PLFAs and PLFAs of each microbial group in these three plantation stand soils were significantly higher in dry season than in rainy season. In dry season, the amounts of microbial total PLFAs, bacteria PLFAs, fungi PLFAs, and actinomycetes PLFAs were the highest in the PM soil, moderate in the MP soil, and the lowest in the EF soil. But in rainy season, the amounts of microbial total PLFAs, bacteria PLFAs, fungi PLFAs, and arbuscular mycorrhizal fungi (AMF) PLFAs in the EF soil were higher than in the MP soil, and were significantly higher than in the PM soil. Principal component analysis (PCA) indicated that the variations in soil microbial community structure composition were affected by both plantation types and seasons. Redundancy analysis (RDA) of soil microbial community structure and environmental factors showed that soil temperature and moisture, pH, total nitrogen content, and ammonium nitrogen content had significant correlations with PLFA signatures. In addition, the ratio of fungi PLFAs to bacteria PLFAs in the MP soil was the highest among the three stand soils within the whole year, indicating that mixed plantation stands could facilitate the stability of the soil ecosystem.

[Effects of different tillage methods on phospholipid fatty acids and enzyme activities in calcareous cinnamon soil].

PubMed

Pei, Xue-Xia; Dang, Jian-You; Zhang, Ding-Yi; Wang, Jiao-Ai; Zhang, Jing

2014-08-01

In order to study changes of physical and chemical characteristics and microbial activities in soil under different tillage methods, effects of four tillage methods, rotary tillage (RT), subsoil tillage (ST), conventional tillage (CT) with corn straw returned to soil, and rotary tillage with no corn straw returned to soil (CK), on phospholipid fatty acids (PLFA) characteristics and hydrolase enzymes activities in calcareous cinnamon soil were investigated. The results showed that soil hydrolase enzymes activities, nutrient contents, microbial diversity varied greatly with the different tillage methods. Returning corn straw to soil increased the kinds, amount of soil total PLFAs, bacteria PLFAs and actonomycetes PLFAs, while decreased the fungi PLFAs, indicating that fungi was more adaptable than bacteria to an infertile environment. ST and CT resulted in higher amounts of total PLFAs, which were 74.7% and 53.3% higher than that of CK, indicating they were more beneficial to the growth of plants. They could also improve soil physical and chemical properties, increase alk-phosphatase, protease and urease activities, which would provide a favorable soil condition for high and stable crop yields.

Functional microbial community response to nutrient pulses by artificial groundwater recharge practice in surface soils and subsoils.

PubMed

Schütz, Kirsten; Kandeler, Ellen; Nagel, Peter; Scheu, Stefan; Ruess, Liliane

2010-06-01

Subsurface microorganisms are essential constituents of the soil purification processes associated with groundwater quality. In particular, soil enzyme activity determines the biodegradation of organic compounds passing through the soil profile. Transects from surface soil to a depth of 3.5 m were investigated for microbial and chemical soil characteristics at two groundwater recharge sites and one control site. The functional diversity of the microbial community was analyzed via the activity of eight enzymes. Acid phosphomonoesterase was dominant across sites and depths, followed by L-leucine aminopeptidase and beta-glucosidase. Structural [e.g. phospholipid fatty acid (PLFA) pattern] and functional microbial diversities were linked to each other at the nonwatered site, whereas amendment with nutrients (DOC, NO(3)(-)) by flooding uncoupled this relationship. Microbial biomass did not differ between sites, whereas microbial respiration was the highest at the watered sites. Hence, excess nutrients available due to artificial groundwater recharge could not compensate for the limitation by others (e.g. phosphorus as assigned by acid phosphomonoesterase activity). Instead, at a similar microbial biomass, waste respiration via overflow metabolism occurred. In summary, ample supply of carbon by flooding led to a separation of decomposition and microbial growth, which may play an important role in regulating purification processes during groundwater recharge.

Responses of Soil Microbial Communities to Experimental Warming in Alpine Grasslands on the Qinghai-Tibet Plateau

PubMed Central

He, Xingyuan; Liu, Wenjie; Zhao, Qian; Zhao, Lin; Tian, Chunjie

2014-01-01

Global surface temperature is predicted to increase by at least 1.5°C by the end of this century. However, the response of soil microbial communities to global warming is still poorly understood, especially in high-elevation grasslands. We therefore conducted an experiment on three types of alpine grasslands on the Qinghai-Tibet Plateau to study the effect of experimental warming on abundance and composition of soil microbial communities at 0–10 and 10–20 cm depths. Plots were passively warmed for 3 years using open-top chambers and compared to adjacent control plots at ambient temperature. Soil microbial communities were assessed using phospholipid fatty acid (PLFA) analysis. We found that 3 years of experimental warming consistently and significantly increased microbial biomass at the 0–10 cm soil depth of alpine swamp meadow (ASM) and alpine steppe (AS) grasslands, and at both the 0–10 and 10–20 cm soil depths of alpine meadow (AM) grasslands, due primarily to the changes in soil temperature, moisture, and plant coverage. Soil microbial community composition was also significantly affected by warming at the 0–10 cm soil depth of ASM and AM and at the 10–20 cm soil depth of AM. Warming significantly decreased the ratio of fungi to bacteria and thus induced a community shift towards bacteria at the 0–10 cm soil depth of ASM and AM. While the ratio of arbuscular mycorrhizal fungi to saprotrophic fungi (AMF/SF) was significantly decreased by warming at the 0–10 cm soil depth of ASM, it was increased at the 0–10 cm soil depth of AM. These results indicate that warming had a strong influence on soil microbial communities in the studied high-elevation grasslands and that the effect was dependent on grassland type. PMID:25083904

Responses of soil enzyme activity and microbial community compositions to nitrogen addition in bulk and microaggregate soil in the temperate steppe of Inner Mongolia

NASA Astrophysics Data System (ADS)

Shi, Yao; Sheng, Lianxi; Wang, Zhongqiang; Zhang, Xinyu; He, Nianpeng; Yu, Qiang

2016-10-01

In order to explore the responses of soil enzyme activities and microbial community compositions to long-term nitrogen (N) addition in both bulk soil and microaggregate of chestnut soil, we conducted a 7-year urea addition experiment with N treatments at 6 levels (0, 56, 112, 224, 392 and 560 kg N ha-1 yr-1) in a temperate steppe of Inner Mongolia in China. Soil properties and the activities of four enzymes involved in carbon (C), nitrogen (N) and phosphorus (P) cycling were measured in both bulk soil and microaggregate, and phospholipid fatty acids (PLFAs) were measured in bulk soil. The results indicated that: 1) in bulk soil, N addition significantly decreased β-1,4-glucosidase (BG) and leucine aminopeptidase (LAP) activities at the treatment amounts of 224, 392 and 560 kg N ha-1 yr-1, and obviously suppressed β-1,4-N-acetylglucosaminidase (NAG) activity at the treatment amount of 560 kg N ha-1 yr-1. N addition enhanced total PLFAs (totPLFAs) and bacterial PLFAs (bacPLFAs) at the treatment amounts of 392 and 560 kg N ha-1 yr-1, respectively, but fungal PLFAs showed no response to N addition. The activities of BG, NAG and LAP were positively correlated with soil pH, but negatively correlated with the concentration of NH 4 + -N; 2) in microaggregate (53-250 μm), the activities of BG, NAG and AP showed no response to increased addition of N, but the significantly decreased LAP activity was observed at the treatment amount of 392 kg N ha-1 yr-1. These results suggested that enzyme activities were more sensitive to N addition than PLFA biomarkers in soil, and LAP activity in microaggregate may be a good indicator for evaluating N cycle response to long-term N addition.

Characterization of redox conditions in groundwater contaminant plumes

NASA Astrophysics Data System (ADS)

Christensen, Thomas H.; Bjerg, Poul L.; Banwart, Steven A.; Jakobsen, Rasmus; Heron, Gorm; Albrechtsen, Hans-Jørgen

2000-10-01

Evaluation of redox conditions in groundwater pollution plumes is often a prerequisite for understanding the behaviour of the pollutants in the plume and for selecting remediation approaches. Measuring of redox conditions in pollution plumes is, however, a fairly recent issue and yet relative few cases have been reported. No standardised or generally accepted approach exists. Slow electrode kinetics and the common lack of internal equilibrium of redox processes in pollution plumes make, with a few exceptions, direct electrochemical measurement and rigorous interpretation of redox potentials dubious, if not erroneous. Several other approaches have been used in addressing redox conditions in pollution plumes: redox-sensitive compounds in groundwater samples, hydrogen concentrations in groundwater, concentrations of volatile fatty acids in groundwater, sediment characteristics and microbial tools, such as MPN counts, PLFA biomarkers and redox bioassays. This paper reviews the principles behind the different approaches, summarizes methods used and evaluates the approaches based on the experience from the reported applications.

Monitoring Biological Activity at Geothermal Power Plants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Peter Pryfogle

2005-09-01

The economic impact of microbial growth in geothermal power plants has been estimated to be as high as $500,000 annually for a 100 MWe plant. Many methods are available to monitor biological activity at these facilities; however, very few plants have any on-line monitoring program in place. Metal coupon, selective culturing (MPN), total organic carbon (TOC), adenosine triphosphate (ATP), respirometry, phospholipid fatty acid (PLFA), and denaturing gradient gel electrophoresis (DGGE) characterizations have been conducted using water samples collected from geothermal plants located in California and Utah. In addition, the on-line performance of a commercial electrochemical monitor, the BIoGEORGE?, has beenmore » evaluated during extended deployments at geothermal facilities. This report provides a review of these techniques, presents data on their application from laboratory and field studies, and discusses their value in characterizing and monitoring biological activities at geothermal power plants.« less

Dietary practices in isolated First Nations communities of northern Canada: combined isotopic and lipid markers provide a good qualitative assessment of store-bought vs locally harvested foods consumption

PubMed Central

Seabert, T; Pal, S; Krümmel, E M; Blais, J M; Imbeault, P; Robidoux, M A; Haman, F

2013-01-01

OBJECTIVE: In First Nations communities of northwestern Ontario, where rates of type 2 diabetes mellitus are some of the highest in the world, ascertaining wild food dietary practices is extremely challenging owing to seasonal availability, environmental factors, life circumstances and language/cultural barriers. The purpose of this study was to determine whether analysis of isotopic and fatty acid (FA) profiles could provide more comprehensive information to discriminate between three categories of wild food consumption (that is, plants and animals) in two isolated First Nations communities of northwestern Ontario. In addition, this analysis also highlights whether wild food consumption as practiced in these two communities can increase circulating levels of polyunsaturated FAs (PUFAs), which provide a number of important metabolic benefits that could impact the prevention/treatment of T2DM. RESULTS: 13C enrichment (in expired CO2, plasma and hair), 15N enrichment (in hair) and FA profiles in plasma phospholipids (phospholipid fatty acid (PL-FA)) were quantified in men and in women consuming various amounts of wild food. 13C/12C ratios were lower and 15N/14N ratios were higher in participants consuming wild food at least once a week. In addition, FA results indicated that the relative contributions of 20:4 Ω-6 and 22:6 Ω-3 to total PL-FAs were higher and 18:2 Ω-6 lower in wild food consumers. CONCLUSION: Together, these findings confirm that isotopic and lipid markers discriminate between the different wild food categories in these two First Nations communities. Knowing the close relationship between dietary intake and the potential role of PUFA in the prevention/treatment of obesity and obesity-related diseases, it is critical to accurately measure the composition of diet for individuals in their specific environments. PMID:24145576

Dietary practices in isolated First Nations communities of northern Canada: combined isotopic and lipid markers provide a good qualitative assessment of store-bought vs locally harvested foods consumption.

PubMed

Seabert, T; Pal, S; Krümmel, E M; Blais, J M; Imbeault, P; Robidoux, M A; Haman, F

2013-10-21

In First Nations communities of northwestern Ontario, where rates of type 2 diabetes mellitus are some of the highest in the world, ascertaining wild food dietary practices is extremely challenging owing to seasonal availability, environmental factors, life circumstances and language/cultural barriers. The purpose of this study was to determine whether analysis of isotopic and fatty acid (FA) profiles could provide more comprehensive information to discriminate between three categories of wild food consumption (that is, plants and animals) in two isolated First Nations communities of northwestern Ontario. In addition, this analysis also highlights whether wild food consumption as practiced in these two communities can increase circulating levels of polyunsaturated FAs (PUFAs), which provide a number of important metabolic benefits that could impact the prevention/treatment of T2DM. (13)C enrichment (in expired CO2, plasma and hair), (15)N enrichment (in hair) and FA profiles in plasma phospholipids (phospholipid fatty acid (PL-FA)) were quantified in men and in women consuming various amounts of wild food. (13)C/(12)C ratios were lower and (15)N/(14)N ratios were higher in participants consuming wild food at least once a week. In addition, FA results indicated that the relative contributions of 20:4 Ω-6 and 22:6 Ω-3 to total PL-FAs were higher and 18:2 Ω-6 lower in wild food consumers. Together, these findings confirm that isotopic and lipid markers discriminate between the different wild food categories in these two First Nations communities. Knowing the close relationship between dietary intake and the potential role of PUFA in the prevention/treatment of obesity and obesity-related diseases, it is critical to accurately measure the composition of diet for individuals in their specific environments.

Bacterial abundance and composition in marine sediments beneath the Ross Ice Shelf, Antarctica.

PubMed

Carr, S A; Vogel, S W; Dunbar, R B; Brandes, J; Spear, J R; Levy, R; Naish, T R; Powell, R D; Wakeham, S G; Mandernack, K W

2013-07-01

Marine sediments of the Ross Sea, Antarctica, harbor microbial communities that play a significant role in the decomposition, mineralization, and recycling of organic carbon (OC). In this study, the cell densities within a 153-cm sediment core from the Ross Sea were estimated based on microbial phospholipid fatty acid (PLFA) concentrations and acridine orange direct cell counts. The resulting densities were as high as 1.7 × 10⁷ cells mL⁻¹ in the top ten centimeters of sediments. These densities are lower than those calculated for most near-shore sites but consistent with deep-sea locations with comparable sedimentation rates. The δ¹³C measurements of PLFAs and sedimentary and dissolved carbon sources, in combination with ribosomal RNA (SSU rRNA) gene pyrosequencing, were used to infer microbial metabolic pathways. The δ¹³C values of dissolved inorganic carbon (DIC) in porewaters ranged downcore from -2.5‰ to -3.7‰, while δ¹³C values for the corresponding sedimentary particulate OC (POC) varied from -26.2‰ to -23.1‰. The δ¹³C values of PLFAs ranged between -29‰ and -35‰ throughout the sediment core, consistent with a microbial community dominated by heterotrophs. The SSU rRNA gene pyrosequencing revealed that members of this microbial community were dominated by β-, δ-, and γ-Proteobacteria, Actinobacteria, Chloroflexi and Bacteroidetes. Among the sequenced organisms, many appear to be related to known heterotrophs that utilize OC sources such as amino acids, oligosaccharides, and lactose, consistent with our interpretation from δ¹³CPLFA analysis. Integrating phospholipids analyses with porewater chemistry, δ¹³CDIC and δ¹³CPOC values and SSU rRNA gene sequences provides a more comprehensive understanding of microbial communities and carbon cycling in marine sediments, including those of this unique ice shelf environment. © 2013 John Wiley & Sons Ltd.

Endotoxin Studies And Biosolids Stabilization Research

EPA Science Inventory

This presentation has three parts; a review of bench-scale endotoxin research, a review of observations from a field scale endotoxin release study, and discussion of biosolids stabilization and characterization by PLFA/FAME microbial community analysis. Endotoxins are part of th...

32 CFR 1285.4 - Responsibilities.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Defense Other Regulations Relating to National Defense DEFENSE LOGISTICS AGENCY MISCELLANEOUS DEFENSE LOGISTICS AGENCY FREEDOM OF INFORMATION ACT PROGRAM § 1285.4 Responsibilities. (a) The Staff Director... program, providing guidance and instructions to PLFA's and PSE's. (2) Designates a FOIA manager to...

Recent (<4 year old) Leaf Litter is Not a Major Source of Microbial Carbon in a Temperate Forest Mineral Soil

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kramer, Christiane; Trumbore, Susan E.; Froberg, Mats J.

2010-01-01

Microbial communities in soil A horizons derive their carbon from several potential sources: organic carbon (C) transported down from overlying litter and organic horizons, root-derived C, or soil organic matter. We took advantage of a multi-year experiment that manipulated the {sup 14}C isotope signature of surface leaf litter inputs in a temperate forest at the Oak Ridge Reservation, Tennessee, USA, to quantify the contribution of recent leaf litter C to microbial respiration and biomarkers in the underlying mineral soil. We observed no measurable difference (< {approx}40{per_thousand} given our current analytical methods) in the radiocarbon signatures of microbial phospholipid fatty acidsmore » (PLFA) isolated from the top 10 cm of mineral soil in plots that experienced 3 years of litterfall that differed in each year by {approx}750{per_thousand} between high-{sup 14}C and low-{sup 14}C treatments. Assuming any difference in {sup 14}C between the high- and low-{sup 14}C plots would reflect C derived from these manipulated litter additions, we estimate that <6% of the microbial C after 4 years was derived from the added 1-4-year-old surface litter. Large contributions of C from litter < 1 year (or >4 years) old (which fell after (or prior to) the manipulation and therefore did not differ between plots) are not supported because the {sup 14}C signatures of the PLFA compounds (averaging 200-220{per_thousand}) is much higher that of the 2004-5 leaf litter (115{per_thousand}) or pre-2000 litter. A mesocosm experiment further demonstrated that C leached from {sup 14}C-enriched surface litter or the O horizon was not a detectable C source in underlying mineral soil microbes during the first eight months after litter addition. Instead a decline in the {sup 14}C of PLFA over the mesocosm experiment likely reflected the loss of a pre-existing substrate not associated with added leaf litter. Measured PLFA {Delta}{sup 14}C signatures were higher than those measured in bulk mineral soil organic matter in our experiments, but fell within the range of {sup 14}C values measured in mineral soil roots. Together, our experiments suggest that root-derived C is the major (>60%) source of C for microbes in these temperate deciduous forest soils.« less

Chapter 11. Community analysis-based methods

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cao, Y.; Wu, C.H.; Andersen, G.L.

2010-05-01

Microbial communities are each a composite of populations whose presence and relative abundance in water or other environmental samples are a direct manifestation of environmental conditions, including the introduction of microbe-rich fecal material and factors promoting persistence of the microbes therein. As shown by culture-independent methods, different animal-host fecal microbial communities appear distinctive, suggesting that their community profiles can be used to differentiate fecal samples and to potentially reveal the presence of host fecal material in environmental waters. Cross-comparisons of microbial communities from different hosts also reveal relative abundances of genetic groups that can be used to distinguish sources. Inmore » increasing order of their information richness, several community analysis methods hold promise for MST applications: phospholipid fatty acid (PLFA) analysis, denaturing gradient gel electrophoresis (DGGE), terminal restriction fragment length polymorphism (TRFLP), cloning/sequencing, and PhyloChip. Specific case studies involving TRFLP and PhyloChip approaches demonstrate the ability of community-based analyses of contaminated waters to confirm a diagnosis of water quality based on host-specific marker(s). The success of community-based MST for comprehensively confirming fecal sources relies extensively upon using appropriate multivariate statistical approaches. While community-based MST is still under evaluation and development as a primary diagnostic tool, results presented herein demonstrate its promise. Coupled with its inherently comprehensive ability to capture an unprecedented amount of microbiological data that is relevant to water quality, the tools for microbial community analysis are increasingly accessible, and community-based approaches have unparalleled potential for translation into rapid, perhaps real-time, monitoring platforms.« less

Glyphosate application increased catabolic activity of gram-negative bacteria but impaired soil fungal community.

PubMed

Liu, Yehao; Li, Yongchun; Hua, Xiaomei; Müller, Karin; Wang, Hailong; Yang, Tongyi; Wang, Qiong; Peng, Xin; Wang, Mengcheng; Pang, Yanjun; Qi, Jinliang; Yang, Yonghua

2018-05-01

Glyphosate is a non-selective organophosphate herbicide that is widely used in agriculture, but its effects on soil microbial communities are highly variable and often contradictory, especially for high dose applications. We applied glyphosate at two rates: the recommended rate of 50 mg active ingredient kg -1 soil and 10-fold this rate to simulate multiple glyphosate applications during a growing season. After 6 months, we investigated the effects on the composition of soil microbial community, the catabolic activity and the genetic diversity of the bacterial community using phospholipid fatty acids (PLFAs), community level catabolic profiles (CLCPs), and 16S rRNA denaturing gradient gel electrophoresis (DGGE). Microbial biomass carbon (C mic ) was reduced by 45%, and the numbers of the cultivable bacteria and fungi were decreased by 84 and 63%, respectively, under the higher glyphosate application rate. According to the PLFA analysis, the fungal biomass was reduced by 29% under both application rates. However, the CLCPs showed that the catabolic activity of the gram-negative (G-) bacterial community was significantly increased under the high glyphosate application rate. Furthermore, the DGGE analysis indicated that the bacterial community in the soil that had received the high glyphosate application rate was dominated by G- bacteria. Real-time PCR results suggested that copies of the glyphosate tolerance gene (EPSPS) increased significantly in the treatment with the high glyphosate application rate. Our results indicated that fungi were impaired through glyphosate while G- bacteria played an important role in the tolerance of microbiota to glyphosate applications.

Contribution of soil fauna to soil functioning in degraded environments: a multidisciplinary approach

NASA Astrophysics Data System (ADS)

Gargiulo, Laura; Mele, Giacomo; Moradi, Jabbar; Kukla, Jaroslav; Jandová, Kateřina; Frouz, Jan

2016-04-01

The restoration of the soil functions is essential for the recovery of highly degraded sites and, consequently, the study of the soil fauna role in the soil development in such environments has great potential from a practical point of view. The soils of the post-mining sites represent unique models for the study of the natural ecological succession because mining creates similar environments characterized by the same substrate, but by different ages according to the year of closure of mines. The aim of this work was to assess the contribution of different species of macrofauna on the evolution of soil structure and on the composition and activity of the microbial community in soil samples subjected to ecological restoration or characterized by spontaneous ecological succession. For this purpose, an experimental test was carried out in two sites characterized by different post-mining conditions: 1) natural succession, 2) reclamation with planting trees. These sites are located in the post-mining area of Sokolov (Czech Republic). For the experimental test repacked soil cores were prepared in laboratory with sieved soil sampled from the two sites. The soil cores were prepared maintaining the sequence of soil horizons present in the field. These samples were inoculated separately with two genera of earthworms (Lumbricus and Aporrectodea) and two of centipedes (Julida and Polydesmus). In particular, based on their body size, were inoculated for each cylinder 2 individuals of millipedes, 1 individual of Lumbricus and 4 individuals of Aporrectodea. For each treatment and for control samples 5 replicates were prepared and all samples were incubated in field for 1 month in the two original sampling sites. After the incubation the samples were removed from the field and transported in laboratory in order to perform the analysis of microbial respiration, of PLFA (phospholipid-derived fatty acids) and ergosterol contents and finally for the characterization of soil structure. All replicates were subjected to soil respiration measurement by means of chemical titration method. Then some replicates were destructively analyzed for PLFA and ergosterol and others were used for the 3D soil image analysis of the soil pore system. The soil cores were imaged using X-ray microtomography and three-dimensional image processing was performed in order to obtain 3D reconstructions and preliminary analysis of the identified biopores. The experimental approach used in this multidisciplinary study showed a promising potential to provide new useful information about the widely differentiated contribution of many types of macrofauna to the formation of the soil pore system and to the development of the soil microbial functions in different types of environments.

The unique chemistry of Eastern Mediterranean water masses selects for distinct microbial communities by depth.

PubMed

Techtmann, Stephen M; Fortney, Julian L; Ayers, Kati A; Joyner, Dominique C; Linley, Thomas D; Pfiffner, Susan M; Hazen, Terry C

2015-01-01

The waters of the Eastern Mediterranean are characterized by unique physical and chemical properties within separate water masses occupying different depths. Distinct water masses are present throughout the oceans, which drive thermohaline circulation. These water masses may contain specific microbial assemblages. The goal of this study was to examine the effect of physical and geological phenomena on the microbial community of the Eastern Mediterranean water column. Chemical measurements were combined with phospholipid fatty acid (PLFA) analysis and high-throughput 16S rRNA sequencing to characterize the microbial community in the water column at five sites. We demonstrate that the chemistry and microbial community of the water column were stratified into three distinct water masses. The salinity and nutrient concentrations vary between these water masses. Nutrient concentrations increased with depth, and salinity was highest in the intermediate water mass. Our PLFA analysis indicated different lipid classes were abundant in each water mass, suggesting that distinct groups of microbes inhabit these water masses. 16S rRNA gene sequencing confirmed the presence of distinct microbial communities in each water mass. Taxa involved in autotrophic nitrogen cycling were enriched in the intermediate water mass suggesting that microbes in this water mass may be important to the nitrogen cycle of the Eastern Mediterranean. The Eastern Mediterranean also contains numerous active hydrocarbon seeps. We sampled above the North Alex Mud Volcano, in order to test the effect of these geological features on the microbial community in the adjacent water column. The community in the waters overlaying the mud volcano was distinct from other communities collected at similar depths and was enriched in known hydrocarbon degrading taxa. Our results demonstrate that physical phenomena such stratification as well as geological phenomena such as mud volcanoes strongly affect microbial community structure in the Eastern Mediterranean water column.

Isotopic biosignatures in carbonate-rich, cyanobacteria-dominated microbial mats of the Cariboo Plateau, B.C.

PubMed

Brady, A L; Druschel, G; Leoni, L; Lim, D S S; Slater, G F

2013-09-01

Photosynthetic activity in carbonate-rich benthic microbial mats located in saline, alkaline lakes on the Cariboo Plateau, B.C. resulted in pCO2 below equilibrium and δ(13) CDIC values up to +6.0‰ above predicted carbon dioxide (CO2 ) equilibrium values, representing a biosignature of photosynthesis. Mat-associated δ(13) Ccarb values ranged from ~4 to 8‰ within any individual lake, with observations of both enrichments (up to 3.8‰) and depletions (up to 11.6‰) relative to the concurrent dissolved inorganic carbon (DIC). Seasonal and annual variations in δ(13) C values reflected the balance between photosynthetic (13) C-enrichment and heterotrophic inputs of (13) C-depleted DIC. Mat microelectrode profiles identified oxic zones where δ(13) Ccarb was within 0.2‰ of surface DIC overlying anoxic zones associated with sulphate reduction where δ(13) Ccarb was depleted by up to 5‰ relative to surface DIC reflecting inputs of (13) C-depleted DIC. δ(13) C values of sulphate reducing bacteria biomarker phospholipid fatty acids (PLFA) were depleted relative to the bulk organic matter by ~4‰, consistent with heterotrophic synthesis, while the majority of PLFA had larger offsets consistent with autotrophy. Mean δ(13) Corg values ranged from -18.7 ± 0.1 to -25.3 ± 1.0‰ with mean Δ(13) Cinorg-org values ranging from 21.1 to 24.2‰, consistent with non-CO2 -limited photosynthesis, suggesting that Precambrian δ(13) Corg values of ~-26‰ do not necessitate higher atmospheric CO2 concentrations. Rather, it is likely that the high DIC and carbonate content of these systems provide a non-limiting carbon source allowing for expression of large photosynthetic offsets, in contrast to the smaller offsets observed in saline, organic-rich and hot spring microbial mats. © 2013 John Wiley & Sons Ltd.

The Unique Chemistry of Eastern Mediterranean Water Masses Selects for Distinct Microbial Communities by Depth

PubMed Central

Techtmann, Stephen M.; Fortney, Julian L.; Ayers, Kati A.; Joyner, Dominique C.; Linley, Thomas D.; Pfiffner, Susan M.; Hazen, Terry C.

2015-01-01

The waters of the Eastern Mediterranean are characterized by unique physical and chemical properties within separate water masses occupying different depths. Distinct water masses are present throughout the oceans, which drive thermohaline circulation. These water masses may contain specific microbial assemblages. The goal of this study was to examine the effect of physical and geological phenomena on the microbial community of the Eastern Mediterranean water column. Chemical measurements were combined with phospholipid fatty acid (PLFA) analysis and high-throughput 16S rRNA sequencing to characterize the microbial community in the water column at five sites. We demonstrate that the chemistry and microbial community of the water column were stratified into three distinct water masses. The salinity and nutrient concentrations vary between these water masses. Nutrient concentrations increased with depth, and salinity was highest in the intermediate water mass. Our PLFA analysis indicated different lipid classes were abundant in each water mass, suggesting that distinct groups of microbes inhabit these water masses. 16S rRNA gene sequencing confirmed the presence of distinct microbial communities in each water mass. Taxa involved in autotrophic nitrogen cycling were enriched in the intermediate water mass suggesting that microbes in this water mass may be important to the nitrogen cycle of the Eastern Mediterranean. The Eastern Mediterranean also contains numerous active hydrocarbon seeps. We sampled above the North Alex Mud Volcano, in order to test the effect of these geological features on the microbial community in the adjacent water column. The community in the waters overlaying the mud volcano was distinct from other communities collected at similar depths and was enriched in known hydrocarbon degrading taxa. Our results demonstrate that physical phenomena such stratification as well as geological phenomena such as mud volcanoes strongly affect microbial community structure in the Eastern Mediterranean water column. PMID:25807542

Key Metabolites and Mechanistic Changes for Salt Tolerance in an Experimentally Evolved Sulfate-Reducing Bacterium, Desulfovibrio vulgaris

PubMed Central

Zhou, Aifen; Lau, Rebecca; Baran, Richard; Ma, Jincai; von Netzer, Frederick; Shi, Weiling; Gorman-Lewis, Drew; Kempher, Megan L.; He, Zhili; Qin, Yujia; Shi, Zhou; Zane, Grant M.; Wu, Liyou; Bowen, Benjamin P.; Northen, Trent R.; Hillesland, Kristina L.; Stahl, David A.; Wall, Judy D.; Arkin, Adam P.

2017-01-01

ABSTRACT Rapid genetic and phenotypic adaptation of the sulfate-reducing bacterium Desulfovibrio vulgaris Hildenborough to salt stress was observed during experimental evolution. In order to identify key metabolites important for salt tolerance, a clone, ES10-5, which was isolated from population ES10 and allowed to experimentally evolve under salt stress for 5,000 generations, was analyzed and compared to clone ES9-11, which was isolated from population ES9 and had evolved under the same conditions for 1,200 generations. These two clones were chosen because they represented the best-adapted clones among six independently evolved populations. ES10-5 acquired new mutations in genes potentially involved in salt tolerance, in addition to the preexisting mutations and different mutations in the same genes as in ES9-11. Most basal abundance changes of metabolites and phospholipid fatty acids (PLFAs) were lower in ES10-5 than ES9-11, but an increase of glutamate and branched PLFA i17:1ω9c under high-salinity conditions was persistent. ES9-11 had decreased cell motility compared to the ancestor; in contrast, ES10-5 showed higher cell motility under both nonstress and high-salinity conditions. Both genotypes displayed better growth energy efficiencies than the ancestor under nonstress or high-salinity conditions. Consistently, ES10-5 did not display most of the basal transcriptional changes observed in ES9-11, but it showed increased expression of genes involved in glutamate biosynthesis, cation efflux, and energy metabolism under high salinity. These results demonstrated the role of glutamate as a key osmolyte and i17:1ω9c as the major PLFA for salt tolerance in D. vulgaris. The mechanistic changes in evolved genotypes suggested that growth energy efficiency might be a key factor for selection. PMID:29138306

Investigations of microbial degradation of polycyclic aromatic hydrocarbons based on 13C-labeled phenanthrene in a soil co-contaminated with trace elements using a plant assisted approach.

PubMed

Wawra, Anna; Friesl-Hanl, Wolfgang; Jäger, Anna; Puschenreiter, Markus; Soja, Gerhard; Reichenauer, Thomas; Watzinger, Andrea

2018-03-01

Co-contaminations of soils with organic and inorganic pollutants are a frequent environmental problem. Due to their toxicity and recalcitrance, the heterogeneous pollutants may persist in soil. The hypothesis of this study was that degradation of polycyclic aromatic hydrocarbons (PAHs) is enhanced if heavy metals in soil are immobilized and their bioavailability reduced. For metal immobilization and enhanced biodegradation, distinct mineral and organic soil amendments (iron oxides, gravel sludge, biochar) were deployed in an incubation batch experiment. The second part of the experiment consisted of a greenhouse pot experiment applying fast-growing and pollution-tolerant woody plants (willow and black locust). Soil amendments initially immobilized NH 4 NO 3 -extractable zinc, cadmium, and lead; after 100 days of incubation, soil amendments showed reductions only for cadmium and a tendency to enhance arsenic mobility. In order to monitor the remediation success, a 13 C-phenanthrene (PHE) label was applied. 13 C-phospholipid fatty acid analysis ( 13 C-PLFA) further enabled the identification of PHE-degrading soil microorganisms. Both experiments exhibited a similar PLFA profile. Gram-negative bacteria (esp. cy17:0, 16:1ω7 + 6, 18:1ω7c) were the most significant microbial group taking up 13 C-PHE. Plants effectively increased the label uptake by gram-positive bacteria and increased the biomass of the fungal biomarker, although their contribution to the degradation process was minor. Plants tended to prolong PAH dissipation in soil; at the end of the experiment, however, all treatments showed equally low total PAH concentrations in soil. While black locust plants tended not to take up potentially toxic trace elements, willows accumulated them in their leaves. The results of this study show that the chosen treatments did not enhance the remediation of the experimental soil.

The unique chemistry of Eastern Mediterranean water masses selects for distinct microbial communities by depth

DOE PAGES

Techtmann, Stephen M.; Fortney, Julian L.; Ayers, Kati A.; ...

2015-03-25

The waters of the Eastern Mediterranean are characterized by unique physical and chemical properties within separate water masses occupying different depths. Distinct water masses are present throughout the oceans, which drive thermohaline circulation. These water masses may contain specific microbial assemblages. The goal of this study was to examine the effect of physical and geological phenomena on the microbial community of the Eastern Mediterranean water column. Chemical measurements were combined with phospholipid fatty acid (PLFA) analysis and high-throughput 16S rRNA sequencing to characterize the microbial community in the water column at five sites. We demonstrate that the chemistry and microbialmore » community of the water column were stratified into three distinct water masses. The salinity and nutrient concentrations vary between these water masses. Nutrient concentrations increased with depth, and salinity was highest in the intermediate water mass. Our PLFA analysis indicated different lipid classes were abundant in each water mass, suggesting that distinct groups of microbes inhabit these water masses. 16S rRNA gene sequencing confirmed the presence of distinct microbial communities in each water mass. Taxa involved in autotrophic nitrogen cycling were enriched in the intermediate water mass suggesting that microbes in this water mass may be important to the nitrogen cycle of the Eastern Mediterranean. The Eastern Mediterranean also contains numerous active hydrocarbon seeps. We sampled above the North Alex Mud Volcano, in order to test the effect of these geological features on the microbial community in the adjacent water column. The community in the waters overlaying the mud volcano was distinct from other communities collected at similar depths and was enriched in known hydrocarbon degrading taxa. Furthermore, our results demonstrate that physical phenomena such stratification as well as geological phenomena such as mud volcanoes strongly affect microbial community structure in the Eastern Mediterranean water column.« less

Microbial metabolism in soil at low temperatures: Mechanisms unraveled by position-specific 13C labeling

NASA Astrophysics Data System (ADS)

Bore, Ezekiel

2016-04-01

Microbial transformation of organic substances in soil is the most important process of the C cycle. Most of the current studies base their information about transformation of organic substances on incubation studies under laboratory conditions and thus, we have a profound knowledge on SOM transformations at ambient temperatures. However, metabolic pathway activities at low temperature are not well understood, despite the fact that the processes are relevant for many soils globally and seasonally. To analyze microbial metabolism at low soil temperatures, isotopomeres of position-specifically 13C labeled glucose were incubated at three temperature; 5, -5 -20 oC. Soils were sampled after 1, 3 and 10 days and additionally after 30 days for samples at -20 °C. The 13C from individual molecule position was quantifed in respired CO2, bulk soil, extractable organic C and extractable microbial biomass by chloroform fumigation extraction (CFE) and cell membranes of microbial communities classified by 13C phospholipid fatty acid (PLFA) analysis. 13CO2 released showed a dominance of the flux from C-1 position at 5 °C. Consequently, at 5 °C, pentose phosphate pathway activity is a dominant metabolic pathway of glucose metabolization. In contrast to -5 °C and -20 oC, metabolic behaviors completely switched towards a preferential respiration of the glucose C-4 position. With decreasing temperature, microorganism strongly shifted towards metabolization of glucose via glycolysis which indicates a switch to cellular maintenance. High recoveries of 13C in extractable microbial biomass at -5 °C indicates optimal growth condition for the microorganisms. PLFA analysis showed high incorporation of 13C into Gram negative bacteria at 5 °C but decreased with temperature. Gram positive bacteria out-competed Gram negatives with decreasing temperature. This study revealed a remarkable microbial activity at temperatures below 0 °C, differing significantly from that at ambient temperatures. These metabolic pathways, can be unraveled based on position-specific labeling.

BIOMASS ACCUMULATION AT THE ELIZABETH CITY AND DENVER FEDERAL CENTER PRBS

EPA Science Inventory

Microbial characterization results, based on PLFA profiles, from the Elizabeth City PRB and adjacent aquifer materials showed a diverse microbiological community dominated by Gram-negative bacteria. Iron core samples from near the upgradient edge of the PRB are typically enriche...

32 CFR 1288.2 - Policy.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 32 National Defense 6 2013-07-01 2013-07-01 false Policy. 1288.2 Section 1288.2 National Defense Other Regulations Relating to National Defense DEFENSE LOGISTICS AGENCY MISCELLANEOUS REGISTRATION OF... restraints warranted by existing conditions at a PLFA. For example, commanders of depots and supply centers...

32 CFR 1288.2 - Policy.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 32 National Defense 6 2012-07-01 2012-07-01 false Policy. 1288.2 Section 1288.2 National Defense Other Regulations Relating to National Defense DEFENSE LOGISTICS AGENCY MISCELLANEOUS REGISTRATION OF... restraints warranted by existing conditions at a PLFA. For example, commanders of depots and supply centers...

32 CFR 1288.2 - Policy.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 32 National Defense 6 2014-07-01 2014-07-01 false Policy. 1288.2 Section 1288.2 National Defense Other Regulations Relating to National Defense DEFENSE LOGISTICS AGENCY MISCELLANEOUS REGISTRATION OF... restraints warranted by existing conditions at a PLFA. For example, commanders of depots and supply centers...

32 CFR 1288.2 - Policy.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 32 National Defense 6 2011-07-01 2011-07-01 false Policy. 1288.2 Section 1288.2 National Defense Other Regulations Relating to National Defense DEFENSE LOGISTICS AGENCY MISCELLANEOUS REGISTRATION OF... restraints warranted by existing conditions at a PLFA. For example, commanders of depots and supply centers...

32 CFR 1288.2 - Policy.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 32 National Defense 6 2010-07-01 2010-07-01 false Policy. 1288.2 Section 1288.2 National Defense Other Regulations Relating to National Defense DEFENSE LOGISTICS AGENCY MISCELLANEOUS REGISTRATION OF... restraints warranted by existing conditions at a PLFA. For example, commanders of depots and supply centers...

Changes in Soil Microbial Community and Its Effect on Carbon Sequestration Following Afforestation on the Loess Plateau, China.

PubMed

Xiang, Yun; Cheng, Man; Huang, Yimei; An, Shaoshan; Darboux, Frédéric

2017-08-22

Afforestation plays an important role in soil protection and ecological restoration. The objective of this study is to understand the effect of afforestation on soil carbon and soil microbial communities in the Loess Plateau of China. We measured two chemically-separated carbon fractions (i.e., humic acid, HA, and fulvic acid, FA) and soil microbial communities within shrublands (18-year-old Caragana korshinskii Kom (shrubland I) and 28-year-old Caragana korshinskii Kom (shrubland II)) and cropland. The size and structure of the soil microbial community was measured by phospholipid fatty acid (PLFA) analysis. The analysis of C-fractions indicated that at a depth of 0-20 cm, FA-C concentration in shrubland I and shrubland II were 1.7 times that of cropland, while HA-C had similar values across all three sites. Total PLFAs, G⁺ (Gram positive) bacterial, G - (Gram negative) bacterial, and actinobacterial PLFAs were highest in shrubland II, followed by shrubland I and finally cropland. Fungal PLFAs were significantly higher in shrubland II compared to the other sites. Additionally, we found a high degree of synergy between main microbial groups (apart from fungi) with FA-C. We concluded that planting C. korshinskii in abandoned cropland could alter the size and structure of soil microbial community, with these changes being closely related to carbon sequestration and humus formation.

Changes in Soil Microbial Community and Its Effect on Carbon Sequestration Following Afforestation on the Loess Plateau, China

PubMed Central

Xiang, Yun; Huang, Yimei; An, Shaoshan; Darboux, Frédéric

2017-01-01

Afforestation plays an important role in soil protection and ecological restoration. The objective of this study is to understand the effect of afforestation on soil carbon and soil microbial communities in the Loess Plateau of China. We measured two chemically-separated carbon fractions (i.e., humic acid, HA, and fulvic acid, FA) and soil microbial communities within shrublands (18-year-old Caragana korshinskii Kom (shrubland I) and 28-year-old Caragana korshinskii Kom (shrubland II)) and cropland. The size and structure of the soil microbial community was measured by phospholipid fatty acid (PLFA) analysis. The analysis of C-fractions indicated that at a depth of 0–20 cm, FA-C concentration in shrubland I and shrubland II were 1.7 times that of cropland, while HA-C had similar values across all three sites. Total PLFAs, G+ (Gram positive) bacterial, G− (Gram negative) bacterial, and actinobacterial PLFAs were highest in shrubland II, followed by shrubland I and finally cropland. Fungal PLFAs were significantly higher in shrubland II compared to the other sites. Additionally, we found a high degree of synergy between main microbial groups (apart from fungi) with FA-C. We concluded that planting C. korshinskii in abandoned cropland could alter the size and structure of soil microbial community, with these changes being closely related to carbon sequestration and humus formation. PMID:28829374

Microbial carbon cycling in oligotrophic regional aquifers near the Tono Uranium Mine, Japan as inferred from δ13C and Δ14C values of in situ phospholipid fatty acids and carbon sources

USGS Publications Warehouse

Mills, Christopher T.; Amano, Yuki; Slater, Gregory F.; Dias, Robert F.; Iwatsuki, Teruki; Mandernack, Kevin W.

2010-01-01

Microorganisms are ubiquitous in deep subsurface environments, but their role in the global carbon cycle is not well-understood. The natural abundance δ13C and Δ14C values of microbial membrane phospholipid fatty acids (PLFAs) were measured and used to assess the carbon sources of bacteria in sedimentary and granitic groundwaters sampled from three boreholes in the vicinity of the Tono Uranium Mine, Gifu, Japan. Sample storage experiments were performed and drill waters analyzed to characterize potential sources of microbial contamination. The most abundant PLFA structures in all waters sampled were 16:0, 16:1ω7c, cy17:0, and 18:1ω7c. A PLFA biomarker for type II methanotrophs, 18:1ω8c, comprised 3% and 18% of total PLFAs in anoxic sedimentary and granitic waters, respectively, sampled from the KNA-6 borehole. The presence of this biomarker was unexpected given that type II methanotrophs are considered obligate aerobes. However, a bacterium that grows aerobically with CH4 as the sole energy source and which also produces 56% of its total PLFAs as 18:1ω8c was isolated from both waters, providing additional evidence for the presence of type II methanotrophs. The Δ14C values determined for type II methanotroph PLFAs in the sedimentary (−861‰) and granite (−867‰) waters were very similar to the Δ14C values of dissolved inorganic carbon (DIC) in each water (∼−850‰). This suggests that type II methanotrophs ultimately derive all their carbon from inorganic sources, whether directly from DIC and/or from CH4 produced by the reduction of DIC. In contrast, δ13C values of type II PLFAs in the sedimentary (−93‰) and granite (−60‰) waters indicate that these organisms use different carbon assimilation schemes in each environment despite very similar δ13CCH4">δ13CCH4 values (∼−95‰) for each water. The δ13CPLFA values (−28‰ to −45‰) of non-methanotrophic bacteria in the KNA-6 LTL water do not clearly distinguish between heterotrophic and autotrophic metabolisms, but Δ14CPLFAvalues indicate that >65% of total bacteria filtered from the KNA-6 LTL water are heterotrophs. Ancient Δ14C values (∼−1000‰) of some PLFAs suggest that many heterotrophs utilize ancient organic matter, perhaps from lignite seams within the sedimentary rocks. The more negative range of δ13CPLFA values determined for the KNA-6 granitic water (−42‰ to −66‰) are likely the result of a microbial ecosystem dominated by chemolithoautotrophy, perhaps fuelled by abiogenic H2. Results of sample storage experiments showed substantial shifts in microbial community composition and δ13CPLFAvalues (as much as 5‰) during 2–4 days of dark, refrigerated, aseptic storage. However, water samples collected and immediately filtered back in the lab from freshly drilled MSB-2 borehole appeared to maintain the same relative relationships between δ13CPLFA values for sedimentary and granitic host rocks as observed for samples directly filtered under artesian flow from the KNA-6 borehole of the Tono Uranium Mine.

In-Well Sediment Incubators to Evaluate Microbial Community Stability and Dynamics following Bioimmobilization of Uranium

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baldwin, Brett R.; Peacock, Aaron D.; Gan, M.

2009-09-23

An in-situ incubation device (ISI) was developed in order to investigate the stability and dynamics of sediment associated microbial communities to prevailing subsurface oxidizing or reducing conditions. Here we describe the use of these devices at the Old Rifle Uranium Mill Tailings Remedial Action (UMTRA) site. During the 7 month deployment oxidized Rifle aquifer background sediments (RABS) were deployed in previously biostimulated wells under iron reducing conditions, cell densities of known iron reducing bacteria including Geobacteraceae increased significantly showing the microbial community response to local subsurface conditions. PLFA profiles of RABS following in situ deployment were strikingly similar to thosemore » of adjacent sediment cores suggesting ISI results could be extrapolated to the native material of the test plots. Results for ISI deployed reduced sediments showed only slight changes in community composition and pointed toward the ability of the ISIs to monitor microbial community stability and response to subsurface conditions.« less

Tracing the flow of plant carbohydrates into the rhizosphere

NASA Astrophysics Data System (ADS)

Gleixner, Gerd

2016-04-01

We investigated the flow of 13C labeled CO2 from plant sugars in leaves, stems and roots into rhizospheric organisms, respired CO2 and soil organic matter in order to better understand the role of the plant-microorganism-soil-continuum for ecosystem carbon cycling. We compared trees and grassland species that had different sugar transport strategies, storage compartments, community compositions and environmental stresses. We used short but highly enriched 13C pulses at controlled CO2 concentrations and temperatures that avoided non-physiological plant responses. We used compound specific 13C measurements of sugars and phospholipids (PLFA) to calculate the carbon turnover of plant sugars and rhizospheric microorganisms. Our results unexpectedly identified transport limitations in the root-shoot carbohydrate transfer, diurnal variations in label respiration and community effects in the carbon transfer to microbial groups. Our results highlight that sophisticated experimental setups and analytical techniques are necessary to gain new knowledge on ecosystem carbon cycling under climate change.

The microbial community in decaying fallen logs varies with critical period in an alpine forest.

PubMed

Chang, Chenhui; Wu, Fuzhong; Yang, Wanqin; Xu, Zhenfeng; Cao, Rui; He, Wei; Tan, Bo; Justine, Meta Francis

2017-01-01

Little information has been available on the shifts in the microbial community in decaying fallen logs during critical periods in cold forests. Minjiang fir (Abies faxoniana) fallen logs in decay classes I-V were in situ incubated on the forest floor of an alpine forest in the eastern Tibet Plateau. The microbial community was investigated during the seasonal snow cover period (SP), snow thawing period (TP), early growing season (EG) and late growing season (LG) using Phosphorous Lipid Fatty Acid (PLFA) analysis. Total microbial biomass and microbial diversity in fallen logs were much more affected by critical period than decay class, whereas decay class had a stronger effect on microbial diversity than on microbial biomass. Abundant microbial biomass and microbial diversity in logs even without the cover of snow were observed in winter, which could not be linked to thermal insulation by snow cover. The freshly decayed logs functioned as an excellent buffer of environmental variation for microbial organisms during the sharp fluctuations in temperature in winter. We also found distinct decay patterns along with seasonality for heartwood, sapwood and bark, which requires further detailed research. Gram- bacteria mainly dominated the shifts in microbial community composition from SP to EG, while fungi and Gram+ bacteria mainly dominated it from SP to TP. Based on previous work and the present study, we conclude that fallen logs on the forest floor alter ecological processes by influencing microbial communities on woody debris and beneath the soil and litter. Our study also emphasizes the need to maintain a number of fallen logs, especially fresh ones, on the forest floor.

Changes in soil microbial community structure influenced by agricultural management practices in a mediterranean agro-ecosystem.

PubMed

García-Orenes, Fuensanta; Morugán-Coronado, Alicia; Zornoza, Raul; Cerdà, Artemi; Scow, Kate

2013-01-01

Agricultural practices have proven to be unsuitable in many cases, causing considerable reductions in soil quality. Land management practices can provide solutions to this problem and contribute to get a sustainable agriculture model. The main objective of this work was to assess the effect of different agricultural management practices on soil microbial community structure (evaluated as abundance of phospholipid fatty acids, PLFA). Five different treatments were selected, based on the most common practices used by farmers in the study area (eastern Spain): residual herbicides, tillage, tillage with oats and oats straw mulching; these agricultural practices were evaluated against an abandoned land after farming and an adjacent long term wild forest coverage. The results showed a substantial level of differentiation in the microbial community structure, in terms of management practices, which was highly associated with soil organic matter content. Addition of oats straw led to a microbial community structure closer to wild forest coverage soil, associated with increases in organic carbon, microbial biomass and fungal abundances. The microbial community composition of the abandoned agricultural soil was characterised by increases in both fungal abundances and the metabolic quotient (soil respiration per unit of microbial biomass), suggesting an increase in the stability of organic carbon. The ratio of bacteria:fungi was higher in wild forest coverage and land abandoned systems, as well as in the soil treated with oat straw. The most intensively managed soils showed higher abundances of bacteria and actinobacteria. Thus, the application of organic matter, such as oats straw, appears to be a sustainable management practice that enhances organic carbon, microbial biomass and activity and fungal abundances, thereby changing the microbial community structure to one more similar to those observed in soils under wild forest coverage.

The microbial community in decaying fallen logs varies with critical period in an alpine forest

PubMed Central

Chang, Chenhui; Wu, Fuzhong; Xu, Zhenfeng; Cao, Rui; He, Wei; Tan, Bo; Justine, Meta Francis

2017-01-01

Little information has been available on the shifts in the microbial community in decaying fallen logs during critical periods in cold forests. Minjiang fir (Abies faxoniana) fallen logs in decay classes I-V were in situ incubated on the forest floor of an alpine forest in the eastern Tibet Plateau. The microbial community was investigated during the seasonal snow cover period (SP), snow thawing period (TP), early growing season (EG) and late growing season (LG) using Phosphorous Lipid Fatty Acid (PLFA) analysis. Total microbial biomass and microbial diversity in fallen logs were much more affected by critical period than decay class, whereas decay class had a stronger effect on microbial diversity than on microbial biomass. Abundant microbial biomass and microbial diversity in logs even without the cover of snow were observed in winter, which could not be linked to thermal insulation by snow cover. The freshly decayed logs functioned as an excellent buffer of environmental variation for microbial organisms during the sharp fluctuations in temperature in winter. We also found distinct decay patterns along with seasonality for heartwood, sapwood and bark, which requires further detailed research. Gram- bacteria mainly dominated the shifts in microbial community composition from SP to EG, while fungi and Gram+ bacteria mainly dominated it from SP to TP. Based on previous work and the present study, we conclude that fallen logs on the forest floor alter ecological processes by influencing microbial communities on woody debris and beneath the soil and litter. Our study also emphasizes the need to maintain a number of fallen logs, especially fresh ones, on the forest floor. PMID:28787465

Influences of Different Halophyte Vegetation on Soil Microbial Community at Temperate Salt Marsh.

PubMed

Chaudhary, Doongar R; Kim, Jinhyun; Kang, Hojeong

2018-04-01

Salt marshes are transitional zone between terrestrial and aquatic ecosystems, occupied mainly by halophytic vegetation which provides numerous ecological services to coastal ecosystem. Halophyte-associated microbial community plays an important role in the adaptation of plants to adverse condition and also affected habitat characteristics. To explore the relationship between halophytes and soil microbial community, we studied the soil enzyme activities, soil microbial community structure, and functional gene abundance in halophytes- (Carex scabrifolia, Phragmites australis, and Suaeda japonica) covered and un-vegetated (mud flat) soils at Suncheon Bay, South Korea. Higher concentrations of total, Gram-positive, Gram-negative, total bacterial, and actinomycetes PLFAs (phospholipid fatty acids) were observed in the soil underneath the halophytes compared with mud flat soil and were highest in Carex soil. Halophyte-covered soils had different microbial community composition due to higher abundance of Gram-negative bacteria than mud flat soil. Similar to PLFA concentrations, the increased activities of β-glucosidase, cellulase, phosphatase, and sulfatase enzymes were observed under halophyte soil compared to mud flat soil and Carex exhibited highest activities. The abundance of archaeal 16S rRNA, fungal ITS, and denitrifying genes (nirK, nirS, and nosZ) were not influenced by the halophytes. Abundance bacterial 16S rRNA and dissimilatory (bi)sulfite (dsrA) genes were highest in Carex-covered soil. The abundance of functional genes involved in methane cycle (mcrA and pmoA) was not affected by the halophytes. However, the ratios of mcrA/pmoA and mcrA/dsrA increased in halophyte-covered soils which indicate higher methanogenesis activities. The finding of the study also suggests that halophytes had increased the microbial and enzyme activities, and played a pivotal role in shaping microbial community structure.

Soil microbial diversity, site conditions, shelter forest land, saline water drip-irrigation, drift desert.

PubMed

Jin, Zhengzhong; Lei, Jiaqiang; Li, Shengyu; Xu, Xinwen

2013-10-01

Soil microbes in forest land are crucial to soil development in extreme areas. In this study, methods of conventional culture, PLFA and PCR-DGGE were utilized to analyze soil microbial quantity, fatty acids and microbial DNA segments of soils subjected to different site conditions in the Tarim Desert Highway forest land. The main results were as follows: the soil microbial amount, diversity indexes of fatty acid and DNA segment differed significantly among sites with different conditions (F < F0.05 ). Specifically, the values were higher in the middle and base of dunes than the top part of dunes and hardened flat sand, but all values for dunes were higher than for drift sand. Bacteria was dominant in the soil microbial community (>84%), followed by actinomycetes and then fungi (<0.05%). Vertical differences in the soil microbial diversity were insignificant at 0-35 cm. Correlation analysis indicated that the forest trees grew better as the soil microbial diversity index increased. Therefore, construction of the Tarim Desert Highway shelter-forest promoted soil biological development; however, for enhancing sand control efficiency and promoting sand development, we should consider the effects of site condition in the construction and regeneration of shelter-forest ecological projects. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Seasonal Variations in Sugar Contents and Microbial Community Behavior in a Ryegrass Soil

NASA Astrophysics Data System (ADS)

Medeiros, P. M.; Fernandes, M. F.; Dick, R. P.; Simoneit, B. R.

2004-12-01

Soil is a complex mixture of numerous inorganic and organic constituents that vary in size, shape, chemical constitution and reactivity, and hosts numerous organisms. Total sugars have been estimated to constitute 10% (average) of soil organic matter, occurring in living and decaying organisms, as well as in extracellular materials. The role of sugars in soils is attributed to their influence on soil structure, chemical processes, plant nutrition and microbial activity. The sources of sugars in soils are: a) plants (the primary source); b) animals (the minor source), and c) microorganisms (fungi, bacteria, algae), which decompose the primary plant and animal material, and synthesize the major part of soil carbohydrates. A particular soil sample provides a momentary glimpse into a dynamic system (continuous addition, degradation and synthesis) that might, except for seasonal variations, be in equilibrium. The purpose of this study is to identify and quantify the major sugars in a grass soil and characterize the relationship between their concentration variations and soil microbial behavior over an annual cycle. Soil samples were collected monthly in a ryegrass field close to Corvallis, Oregon, and analyzed by gas chromatography-mass spectrometry as total silylated extracts for sugar composition, and by gas chromatography-flame ionization as fatty acid methyl esters derived from phospholipids and neutral lipids (PLFA and NLFA, respectively). The preliminary results of the first six-month experiment (from January to June, 2004) show that as the ambient temperatures increase the sugar concentrations (glucose, fructose, sucrose and trehalose) also tend to increase in the soil. A decrease is observed in March when precipitation was low during the whole month. The same trend is observed for the active biomass of fungi and bacteria estimated by their fatty acids derived from phospholipids. Fatty acids 18:2ω 6c and 18:3ω 6c are used as fungal biomarkers. Branched (15:0i, 15:0a, 16:0i) and monounsaturated fatty acids (16:1ω 7c) are used as biomarkers for gram-positive and gram-negative bacteria, respectively. The contents of 18:2ω 6c and 18:3ω 6c from neutral lipids, which are used as an index of fungal storage, have a significant increase in June, similarly to the disaccharide trehalose. This increase in fungal lipid storage may have occurred in response to the large input of detrital carbon into the soil from cutting the grass early in that month.

Effect of long-term drought on carbon allocation and nitrogen uptake of Pinus sylvestris seedlings

NASA Astrophysics Data System (ADS)

Pumpanen, Jukka; Aaltonen, Heidi; Lindén, Aki; Köster, Kajar; Biasi, Christina; Heinonsalo, Jussi

2015-04-01

Weather extremes such as drought events are expected to increase in the future as a result of climate change. The drought affects the allocation of carbon assimilated by plants e.g. by modifying the root to shoot ratio, amount of fine roots and the amount of mycorrhizal fungal hyphae. We studied the effect of long term drought on the allocation of carbon in a common garden experiment with 4-year-old Pinus sylvestris seedlings. Half of the seedlings were exposed to long-term drought by setting the soil water content close to wilting point for over two growing seasons whereas the other half was grown in soil close to field capacity. We conducted a pulse labelling with 13CO2 in the end of the study by injecting a known amount of 13C enriched CO2 to the seedlings and measuring the CO2 uptake and distribution of 13C to the biomass of the seedlings and to the root and rhizosphere respiration. In addition, we studied the effect of drought on the decomposition of needle litter and uptake of nitrogen by 15N labelled needles buried in the soil in litter bags. The litterbags were collected and harvested in the end of the experiment and the changes in microbial community in the litterbags were studied from the phospholipid fatty acid (PLFA) composition. We also determined the 15N isotope concentrations from the needles of the seedlings to study the effect of drought on the nitrogen uptake of the seedlings. Our results indicate that the drought had a significant effect both on the biomass allocation of the seedlings and on the microbial species composition. The amount of carbon allocated belowground was much higher in the seedlings exposed to drought compared to the control seedlings. The seedlings seemed to adapt their carbon allocation to long-term drought to sustain adequate needle biomass and water uptake. The seedlings also adapted their osmotic potential and photosynthesis capacity to sustain the long-term drought as was indicated by the measurements of osmotic potential and photosynthetic light response.

Divergence of dominant factors in soil microbial communities and functions in forest ecosystems along a climatic gradient

NASA Astrophysics Data System (ADS)

Xu, Zhiwei; Yu, Guirui; Zhang, Xinyu; He, Nianpeng; Wang, Qiufeng; Wang, Shengzhong; Xu, Xiaofeng; Wang, Ruili; Zhao, Ning

2018-03-01

Soil microorganisms play an important role in regulating nutrient cycling in terrestrial ecosystems. Most of the studies conducted thus far have been confined to a single forest biome or have focused on one or two controlling factors, and few have dealt with the integrated effects of climate, vegetation, and soil substrate availability on soil microbial communities and functions among different forests. In this study, we used phospholipid-derived fatty acid (PLFA) analysis to investigate soil microbial community structure and extracellular enzymatic activities to evaluate the functional potential of soil microbes of different types of forests in three different climatic zones along the north-south transect in eastern China (NSTEC). Both climate and forest type had significant effects on soil enzyme activities and microbial communities with considerable interactive effects. Except for soil acid phosphatase (AP), the other three enzyme activities were much higher in the warm temperate zone than in the temperate and the subtropical climate zones. The soil total PLFAs and bacteria were much higher in the temperate zone than in the warm temperate and the subtropical zones. The soil β-glucosidase (BG) and N-acetylglucosaminidase (NAG) activities were highest in the coniferous forest. Except for the soil fungi and fungi-bacteria (F/B), the different groups of microbial PLFAs were much higher in the conifer broad-leaved mixed forests than in the coniferous forests and the broad-leaved forests. In general, soil enzyme activities and microbial PLFAs were higher in primary forests than in secondary forests in temperate and warm temperate regions. In the subtropical region, soil enzyme activities were lower in the primary forests than in the secondary forests and microbial PLFAs did not differ significantly between primary and secondary forests. Different compositions of the tree species may cause variations in soil microbial communities and enzyme activities. Our results showed that the main controls on soil microbes and functions vary in different climatic zones and that the effects of soil moisture content, soil temperature, clay content, and the soil N / P ratio were considerable. This information will add value to the modeling of microbial processes and will contribute to carbon cycling in large-scale carbon models.

Microbial utilization of rice straw and its derived biochar in a paddy soil.

PubMed

Pan, Fuxia; Li, Yaying; Chapman, Stephen James; Khan, Sardar; Yao, Huaiying

2016-07-15

The application of straw and biochar to soil has received great attention because of their potential benefits such as fertility improvement and carbon (C) sequestration. The abiotic effects of these materials on C and nitrogen (N) cycling in the soil ecosystem have been previously investigated, however, the effects of straw or its derived biochar on the soil microbial community structure and function are not well understood. For this purpose, a short-term incubation experiment was conducted using (13)C-labeled rice straw and its derived biochar ((13)C-labeled biochar) to deepen our understanding about soil microbial community dynamics and function in C sequestration and greenhouse gas emission in the acidic paddy soil amended with these materials. Regarding microbial function, biochar and straw applications increased CO2 emission in the initial stage of incubation and reached the highest level (0.52 and 3.96mgCkg(-1)soilh(-1)) at 1d and 3d after incubation, respectively. Straw amendment significantly (p<0.01) increased respiration rate, total phospholipid fatty acids (PLFAs) and (13)C-PLFA as compared to biochar amendment and the control. The amount and percent of Gram positive bacteria, fungi and actinomycetes were also significantly (p<0.05) higher in (13)C-labeled straw amended soil than the (13)C-labeled biochar amended soil. According to the (13)C data, 23 different PLFAs were derived from straw amended paddy soil, while only 17 PLFAs were derived from biochar amendments. The profile of (13)C-PLFAs derived from straw amendment was significantly (p<0.01) different from biochar amendment. The PLFAs18:1ω7c and cy17:0 (indicators of Gram negative bacteria) showed high relative abundances in the biochar amendment, while 10Me18:0, i17:0 and 18:2ω6,9c (indicators of actinomycetes, Gram positive bacteria and fungi, respectively) showed high relative abundance in the straw amendments. Our results suggest that the function, size and structure of the microbial community were strongly influenced by the substrate composition and availability. Copyright © 2016 Elsevier B.V. All rights reserved.

Long-term carbon exclusion alters soil microbial function but not community structure across forests of contrasting productivity

NASA Astrophysics Data System (ADS)

Hart, S. C.; Dove, N. C.; Stark, J.

2017-12-01

While it is well-documented that distinct heterotrophic microbial communities emerge under different conditions of carbon (C) availability, the response of soil microbial communities and their function to long-term conditions of C exclusion in situ has yet to be investigated. We evaluated the role of C in controlling soil microbial communities and function by experimentally excluding plant C inputs for nine years at four forest sites along a productivity gradient in Oregon, USA. Carbon exclusion treatments were implemented by root trenching to a depth of 30 cm using 25-cm diameter steel pipe, and minimizing aboveground inputs as plant litter by covering the pipe with a 1-mm mesh screen. After nine years, we measured rates of gross and net nitrogen (N) transformations and microbial respiration in situ in the upper 15-cm of mineral soil in both C excluded plots and undisturbed control soils. We measured the soil total C and N concentration and potential extracellular enzyme activities. We used phospholipid fatty acid (PLFA) analysis to determine potential changes in the microbial community structure. Nine years of C exclusion reduced soil total C by about 20%, except at the highest productivity site where no statistically significant change was observed. Although PLFA community structure and microbial C were unchanged, microbial respiration was reduced by 15-45% at all sites. Similarly, specific extracellular enzyme activities for all enzymes increased at these sites with C exclusion, suggesting that the microbial communities were substrate-limited. Although gross N mineralization decreased under C exclusion, decreases in gross N immobilization were greater, resulting in increased net N mineralization rates in all but the lowest productivity site. Furthermore, C exclusion only increased net nitrification in the highest productivity site. Although these field-based results are largely consistent with previous laboratory studies indicating a strong coupling between C and N biogeochemical cycles, they build upon this earlier research by suggesting that the "C connection" to the N cycle depends on the rate of C cycling within the ecosystem.

Carbon Metabolism of Soil microorganisms at Low Temperatures: Position-Specific 13C Labeled Glucose Reveals the Story

NASA Astrophysics Data System (ADS)

Apostel, C.; Bore, E. K.; Halicki, S.; Kuzyakov, Y.; Dippold, M.

2015-12-01

Metabolic pathway activities at low temperature are not well understood, despite the fact that the processes are relevant for many soils globally and seasonally. To analyze soil metabolism at low temperature, isotopomeres of position-specifically 13C labeled glucose were applied at three temperature levels; +5, -5 -20 oC. In additon, one sterilization treatment with sodium azide at +5 oC was also performed. Soils were incubated for 1, 3 and 10 days while soil samples at -20 oC were additionally sampled after 30 days. The 13C from individual molecule position in respired CO2 was quantifed. Incorporation of 13C in bulk soil, extractable microbial biomass by chloroform fumigation extraction (CFE) and cell membranes of different microbial communities classified by 13C phospholipid fatty acid analysis (PLFA) was carried out. Our 13CO2 data showed a dominance of C-1 respiration at +5 °C for treatments with and without sodium azide, but total respiration for sodium azide inhibited treatments increased by 14%. In contrast, at -5 and -20 oC metabolic behavior showed intermingling of preferential respiration of the glucose C-4 and C-1 positions. Therefore, at +5 °C, pentose phosphate pathway activity is a dominant metabolic pathway used by microorganisms to metabolize glucose. The respiration increase due to NaN3 inhibition was attributed to endoenzymes released from dead organisms that are stabilized at the soil matrix and have access to suitable substrate and co-factors to permit their funtions. Our PLFA analysis showed that incorporation of glucose 13C was higher in Gram negative bacteria than other microbial groups as they are most competitive for LMWOS. Only a limited amount of microbial groups maintained their glucose utilizing activity at -5 and -20 °C and they strongly shifted towards a metabolization of glucose via both glycolysis and pentose phosphate pathways indicating both growth and cellular maintenance. This study revealed a remarkable microbial acitivity at low temperatures which differs significantly from our observations at ambient temperature, which could be unraveled based on position-specific labeling.

PLFA profiling of microbial community structure and seasonal shifts in soils of a Douglas-fir chronosequence

Treesearch

Jennifer Moore-Kucera; Richard P. Dick

2008-01-01

The impact and frequency of forest harvesting could significantly affect soil microbial community (SMC) structure and functioning. The ability of soil microorganisms to perform biogeochemical processes is critical for sustaining forest productivity and has a direct impact on decomposition dynamics and carbon storage potential. The Wind River Canopy Crane Research...

Unique honey bee (Apis mellifera) hive component-based communities as detected by a hybrid of phospholipid fatty-acid and fatty-acid methyl ester analyses.

PubMed

Grubbs, Kirk J; Scott, Jarrod J; Budsberg, Kevin J; Read, Harry; Balser, Teri C; Currie, Cameron R

2015-01-01

Microbial communities (microbiomes) are associated with almost all metazoans, including the honey bee Apis mellifera. Honey bees are social insects, maintaining complex hive systems composed of a variety of integral components including bees, comb, propolis, honey, and stored pollen. Given that the different components within hives can be physically separated and are nutritionally variable, we hypothesize that unique microbial communities may occur within the different microenvironments of honey bee colonies. To explore this hypothesis and to provide further insights into the microbiome of honey bees, we use a hybrid of fatty acid methyl ester (FAME) and phospholipid-derived fatty acid (PLFA) analysis to produce broad, lipid-based microbial community profiles of stored pollen, adults, pupae, honey, empty comb, and propolis for 11 honey bee hives. Averaging component lipid profiles by hive, we show that, in decreasing order, lipid markers representing fungi, Gram-negative bacteria, and Gram-positive bacteria have the highest relative abundances within honey bee colonies. Our lipid profiles reveal the presence of viable microbial communities in each of the six hive components sampled, with overall microbial community richness varying from lowest to highest in honey, comb, pupae, pollen, adults and propolis, respectively. Finally, microbial community lipid profiles were more similar when compared by component than by hive, location, or sampling year. Specifically, we found that individual hive components typically exhibited several dominant lipids and that these dominant lipids differ between components. Principal component and two-way clustering analyses both support significant grouping of lipids by hive component. Our findings indicate that in addition to the microbial communities present in individual workers, honey bee hives have resident microbial communities associated with different colony components.

Unique Honey Bee (Apis mellifera) Hive Component-Based Communities as Detected by a Hybrid of Phospholipid Fatty-Acid and Fatty-Acid Methyl Ester Analyses

PubMed Central

2015-01-01

Microbial communities (microbiomes) are associated with almost all metazoans, including the honey bee Apis mellifera. Honey bees are social insects, maintaining complex hive systems composed of a variety of integral components including bees, comb, propolis, honey, and stored pollen. Given that the different components within hives can be physically separated and are nutritionally variable, we hypothesize that unique microbial communities may occur within the different microenvironments of honey bee colonies. To explore this hypothesis and to provide further insights into the microbiome of honey bees, we use a hybrid of fatty acid methyl ester (FAME) and phospholipid-derived fatty acid (PLFA) analysis to produce broad, lipid-based microbial community profiles of stored pollen, adults, pupae, honey, empty comb, and propolis for 11 honey bee hives. Averaging component lipid profiles by hive, we show that, in decreasing order, lipid markers representing fungi, Gram-negative bacteria, and Gram-positive bacteria have the highest relative abundances within honey bee colonies. Our lipid profiles reveal the presence of viable microbial communities in each of the six hive components sampled, with overall microbial community richness varying from lowest to highest in honey, comb, pupae, pollen, adults and propolis, respectively. Finally, microbial community lipid profiles were more similar when compared by component than by hive, location, or sampling year. Specifically, we found that individual hive components typically exhibited several dominant lipids and that these dominant lipids differ between components. Principal component and two-way clustering analyses both support significant grouping of lipids by hive component. Our findings indicate that in addition to the microbial communities present in individual workers, honey bee hives have resident microbial communities associated with different colony components. PMID:25849080

Microbial Community Dynamics during the Bioremediation Process of Chlorimuron-Ethyl-Contaminated Soil by Hansschlegelia sp. Strain CHL1

PubMed Central

Yang, Liqiang; Li, Xinyu; Li, Xu; Su, Zhencheng; Zhang, Chenggang; Zhang, Huiwen

2015-01-01

Long-term and excessive application of chlorimuron-ethyl has led to a series of environmental problems. Strain Hansschlegelia sp. CHL1, a highly efficient chlorimuron-ethyl degrading bacterium isolated in our previous study, was employed in the current soil bioremediation study. The residues of chlorimuron-ethyl in soils were detected, and the changes of soil microbial communities were investigated by phospholipid fatty acid (PLFA) analysis. The results showed that strain CHL1 exhibited significant chlorimuron-ethyl degradation ability at wide range of concentrations between 10μg kg-1 and 1000μg kg-1. High concentrations of chlorimuron-ethyl significantly decreased the total concentration of PLFAs and the Shannon-Wiener indices and increased the stress level of microbes in soils. The inoculation with strain CHL1, however, reduced the inhibition on soil microbes caused by chlorimuron-ethyl. The results demonstrated that strain CHL1 is effective in the remediation of chlorimuron-ethyl-contaminated soil, and has the potential to remediate chlorimuron-ethyl contaminated soils in situ. PMID:25689050

Resolving the chemical heterogeneity of natural organic matter: new insights from comprehensive two-dimensional liquid chromatography.

PubMed

Duarte, Regina M B O; Barros, Ana C; Duarte, Armando C

2012-08-03

For the purpose of resolving the chemical heterogeneity of natural organic matter (NOM), comprehensive two-dimensional liquid chromatography (LC×LC) was employed for the first time to map the hydrophobicity versus molecular weight (MW) distribution of two well-known complex organic mixtures: Suwannee River Fulvic Acids (SR-FA) and Pony Lake Fulvic Acids (PL-FA). Two methods have been developed using either a conventional reversed-phase (RP) silica column or a mixed-mode hydrophilic interaction column operating under aqueous RP mode in the first dimension, and a size-exclusion column in the second dimension. The LC×LC fractions were screened on-line by UV at 254 nm, molecular fluorescence at excitation/emission wavelengths (λ(Exc)/λ(Em)) of 240/450 nm, and by evaporative light scattering. The MW distributions of these two NOM samples were further characterized by number (Mn) and weight (Mw) average MW, and by polydispersity (Mw/Mn). Findings suggest that the combination of two independent separation mechanisms is promising in extend the range of NOM separation. For the cases where NOM separation was accomplished, smaller Mw group fractions seem to be related to a more hydrophobic nature. Regardless of the detection method, the complete range of MW distribution provided by both comprehensive LC×LC methods was found to be lower than those reported in the literature. Copyright © 2012 Elsevier B.V. All rights reserved.

Interactive Effects of Nitrogen and Phosphorus on Soil Microbial Communities in a Tropical Forest

PubMed Central

Liu, Lei; Zhang, Tao; Gilliam, Frank S.; Gundersen, Per; Zhang, Wei; Chen, Hao; Mo, Jiangming

2013-01-01

Elevated nitrogen (N) deposition in humid tropical regions may exacerbate phosphorus (P) deficiency in forests on highly weathered soils. However, it is not clear how P availability affects soil microbes and soil carbon (C), or how P processes interact with N deposition in tropical forests. We examined the effects of N and P additions on soil microbes and soil C pools in a N-saturated old-growth tropical forest in southern China to test the hypotheses that (1) N and P addition will have opposing effects on soil microbial biomass and activity, (2) N and P addition will alter the composition of the microbial community, (3) the addition of N and P will have interactive effects on soil microbes and (4) addition-mediated changes in microbial communities would feed back on soil C pools. Phospholipid fatty acid (PLFA) analysis was used to quantify the soil microbial community following four treatments: Control, N addition (15 g N m−2 yr−1), P addition (15 g P m−2 yr−1), and N&P addition (15 g N m−2 yr−1 plus 15 g P m−2 yr−1). These were applied from 2007 to 2011. Whereas additions of P increased soil microbial biomass, additions of N reduced soil microbial biomass. These effects, however, were transient, disappearing over longer periods. Moreover, N additions significantly increased relative abundance of fungal PLFAs and P additions significantly increased relative abundance of arbuscular mycorrhizal (AM) fungi PLFAs. Nitrogen addition had a negative effect on light fraction C, but no effect on heavy fraction C and total soil C. In contrast, P addition significantly decreased both light fraction C and total soil C. However, there were no interactions between N addition and P addition on soil microbes. Our results suggest that these nutrients are not co-limiting, and that P rather than N is limiting in this tropical forest. PMID:23593427

Microbial Community Shifts Associated with RDX Loss in a Saturated and Well-Drained Surface Soil

DTIC Science & Technology

2005-03-01

community containing firmicutes (36%), proteobacteria (54%), actinobacteria (8%), and bacteroidetes (1%). The unsaturated soil contained a greater number of...genera (2.5 times that of the saturated soil) within similar phyla (19% firmicutes, 66% proteobacteria, 6% actinobacteria , 2% bacteroidetes, and 7...by the PLFA analysis. The T-RFLP analysis identified firmicutes (36%), proteobacteria (54%), actinobacteria (8%), and bacteroidetes (1%) in the

A comparison of indexing methods to evaluate quality of soils subjected to different erosion: the role of soil microbiological properties.

NASA Astrophysics Data System (ADS)

Romaniuk, Romina; Lidia, Giuffre; Alejandro, Costantini; Norberto, Bartoloni; Paolo, Nannipieri

2010-05-01

Soil quality assessment is needed to evaluate the soil conditions and sustainability of soil and crop management properties, and thus requires a systematic approach to select and interpret soil properties to be used as indicators. The aim of this work was to evaluate and compare different indexing methods to assess quality of an undisturbed grassland soil (UN), a degraded pasture soil (GL) and a no tilled soil (NT) with four different A horizon depths (25, 23, 19 and 14 cm) reflecting a diverse erosion. Twenty four soil properties were measured from 0 to10 (1) and 10 to 20 cm. (2) and a minimum data set was chosen by multivariate principal component analysis (PCA) considering all measured soil properties together (A), or according to their classification in physical, chemical or microbiological (B) properties. The measured soil properties involved either inexpensive or not laborious standard protocols, to be used in routine laboratory analysis (simple soil quality index - SSQI), or a more laborious, time consuming and expensive protocols to determine microbial diversity and microbial functionality by methyl ester fatty acids (PLFA) and catabolic response profiles (CRP), respectively (complex soil quality index - CSQI). The selected properties were linearly normalized and integrated by the weight additive method to calculate SSQI A, SSQI B, CSQI A and CSQI B indices. Two microbiological soil quality indices (MSQI) were also calculated: the MSQI 1 only considered microbiological properties according to the procedure used for calculating SQI; the MSQI 2 was calculated by considering microbial carbon biomass (MCB), microbial activity (Resp) and functional diversity determined by CPR (E). The soil quality indices were SSQI A = MCB 1 + Particulate Organic Carbon (POC)1 + Mean Weight Diameter (MWD)1; SSQI B = Saturated hydraulic conductivity (K) 1 + Total Organic Carbon (TOC) 1 + MCB 1; CSQI A = MCB 1 + POC 1 + MWD 1; CSQI B = K 1+ TOC 1+ 0.3 * (MCB 1+ i/a +POC 1) + 0,05 * (E + cy/pre), where i/a and cy/pre are the iso/anteiso and cyclopropyl/precursors ratios determined by PLFA; MSQI 1 (0,3 * (MCB 1+ i/a 1 +POC 1) + 0,05 * (E 1+ cy/pre 1) ) and MSQI 2 (MCB 1+Resp 1+ E 1). All the calculated indices differentiated references plots (UN and GL), from those under no tillage (NT) system. Values were similar in NT plots with low erosion levels (NT 25 and 23) but higher than values of plots with high erosion (NT 19 and 14). Soil quality indices constructed by procedure B, (SSQI B and CSQI B) differentiated among the studied plots with the same or higher sensitivity than the other indices and allowed evaluating the impact of soil management practices and erosion on soil physical, chemical and microbiological properties. The lack of indicators representing all soil properties (physical, chemical and biological) in SQI constructed by procedure A could decrease the index sensitivity to changes in management; and the same may happen when physical, chemical and biological properties present different weights into the calculated SQI. The inclusion of CRP and PLFA data in the indices slightly increased or did not increase the index sensitivity (CSQI A and CSQI B). Generally microbiological indices (MSQI 1 and MSQI 2) were highly sensitive to soil erosion. However, we suggest that indices integrating physical, chemical and microbiological properties may give a more complete view of the soil quality than indices only based on measurement of a few microbiological properties.

Identifying microbial carbon sources during ethanol and toluene biodegradation in a pilot-scale experimental aquifer system using isotopic analysis

NASA Astrophysics Data System (ADS)

Clay, S.; McLeod, H.; Smith, J. E.; Roy, J. W.; Slater, G. F.

2013-12-01

Combining ethanol with gasoline has become increasingly common in order to create more environmentally conscience transportation fuels. These blended fuels are favourable alternatives since ethanol is a non-toxic and highly labile renewable biomass-based resource which is an effective fuel oxygenate that reduces air pollution. Recent research however, has indicated that upon accidental release into groundwater systems, the preferential microbial metabolism of ethanol can cause progressively reducing conditions leading to slower biodegradation of petroleum hydrocarbons. Therefore, the presence of ethanol can result in greater persistence of BTEX compounds and longer hydrocarbon plumes in groundwater systems. Microbial biodegradation and community carbon sources coupled to aqueous geochemistry were monitored in a pilot-scale laboratory tank (80cm x 525cm x 175cm) simulating an unconfined sand aquifer. Dissolved ethanol and toluene were continuously injected into the aquifer at a controlled rate over 330 days. Carbon isotope analyses were performed on phospholipid fatty acid (PLFA) samples collected from 4 different locations along the aquifer. Initial stable carbon isotope values measured over days 160-185 in the bacterial PLFA ranged from δ13C = -10 to -21‰, which is indicative of dominant ethanol incorporation by the micro-organisms based on the isotopic signature of ethanol derived from corn, a C4 plant. A negative shift to δ13C = -10 to -30‰ observed over days 185-200, suggests a change in microbial metabolisms associated with less ethanol incorporation. This generally corresponds to a decrease in ethanol concentrations from day 40 to full attenuation at approximately day 160, and the onset of toluene depletion observed on day 120 and continuing thereafter. In addition, aqueous methane concentrations first detected on day 115 continued to rise to 0.38-0.70 mmol/L at all monitoring locations, demonstrating a significant redox shift to low energy methanogenic metabolisms. On-going archaeal lipid analyses are expected to capture the establishment of methanogenic communities and provide insight into carbon use by these communities. Furthermore, radiocarbon analysis will aid in tracking the biodegradation of ethanol and toluene. Ultimately this research aims to illustrate the preferential biodegradation of ethanol in a gasoline mixture, and identify the carbon sources utilized by an evolving microbial community using isotopic analyses to improve assessments and remediation strategies at sites contaminated with ethanol-blended fuels.

Microbial sulfate reduction and metal attenuation in pH 4 acid mine water

USGS Publications Warehouse

Church, C.D.; Wilkin, R.T.; Alpers, Charles N.; Rye, R.O.; Blaine, R.B.

2007-01-01

Sediments recovered from the flooded mine workings of the Penn Mine, a Cu-Zn mine abandoned since the early 1960s, were cultured for anaerobic bacteria over a range of pH (4.0 to 7.5). The molecular biology of sediments and cultures was studied to determine whether sulfate-reducing bacteria (SRB) were active in moderately acidic conditions present in the underground mine workings. Here we document multiple, independent analyses and show evidence that sulfate reduction and associated metal attenuation are occurring in the pH-4 mine environment. Water-chemistry analyses of the mine water reveal: (1) preferential complexation and precipitation by H2S of Cu and Cd, relative to Zn; (2) stable isotope ratios of 34S/32S and 18O/16O in dissolved SO4 that are 2-3 ??? heavier in the mine water, relative to those in surface waters; (3) reduction/oxidation conditions and dissolved gas concentrations consistent with conditions to support anaerobic processes such as sulfate reduction. Scanning electron microscope (SEM) analyses of sediment show 1.5-micrometer, spherical ZnS precipitates. Phospholipid fatty acid (PLFA) and denaturing gradient gel electrophoresis (DGGE) analyses of Penn Mine sediment show a high biomass level with a moderately diverse community structure composed primarily of iron- and sulfate-reducing bacteria. Cultures of sediment from the mine produced dissolved sulfide at pH values near 7 and near 4, forming precipitates of either iron sulfide or elemental sulfur. DGGE coupled with sequence and phylogenetic analysis of 16S rDNA gene segments showed populations of Desulfosporosinus and Desulfitobacterium in Penn Mine sediment and laboratory cultures. ?? 2007 Church et al; licensee BioMed Central Ltd.

Microbial sulfate reduction and metal attenuation in pH 4 acid mine water

PubMed Central

Church, Clinton D; Wilkin, Richard T; Alpers, Charles N; Rye, Robert O; McCleskey, R Blaine

2007-01-01

Sediments recovered from the flooded mine workings of the Penn Mine, a Cu-Zn mine abandoned since the early 1960s, were cultured for anaerobic bacteria over a range of pH (4.0 to 7.5). The molecular biology of sediments and cultures was studied to determine whether sulfate-reducing bacteria (SRB) were active in moderately acidic conditions present in the underground mine workings. Here we document multiple, independent analyses and show evidence that sulfate reduction and associated metal attenuation are occurring in the pH-4 mine environment. Water-chemistry analyses of the mine water reveal: (1) preferential complexation and precipitation by H2S of Cu and Cd, relative to Zn; (2) stable isotope ratios of 34S/32S and 18O/16O in dissolved SO4 that are 2–3 ‰ heavier in the mine water, relative to those in surface waters; (3) reduction/oxidation conditions and dissolved gas concentrations consistent with conditions to support anaerobic processes such as sulfate reduction. Scanning electron microscope (SEM) analyses of sediment show 1.5-micrometer, spherical ZnS precipitates. Phospholipid fatty acid (PLFA) and denaturing gradient gel electrophoresis (DGGE) analyses of Penn Mine sediment show a high biomass level with a moderately diverse community structure composed primarily of iron- and sulfate-reducing bacteria. Cultures of sediment from the mine produced dissolved sulfide at pH values near 7 and near 4, forming precipitates of either iron sulfide or elemental sulfur. DGGE coupled with sequence and phylogenetic analysis of 16S rDNA gene segments showed populations of Desulfosporosinus and Desulfitobacterium in Penn Mine sediment and laboratory cultures. PMID:17956615

Production and Dietary Uptake of PUFA by Piezophilic Bacteria, Implications for Marine Biogeochemistry

NASA Astrophysics Data System (ADS)

Fang, J.; Chan, O.; Agarkar, N.; Kato, C.; Sato, T.

2003-12-01

Polyunsaturated fatty acids (PUFAs) have been used extensively as proxies for determining the source and preservation of organic matter in marine sediments. However, the origin of polyunsaturated fatty acids in deep-sea sediments is not well understood; the ultimate source of PUFAs is only partially constrained. At issue is whether PUFAs in deep-sea sediments are derived from the primary production of the photic zone or from the in situ piezophilic bacterial production in the deep-sea, or both. In this study, we tested three deep-sea piezophilic strains, Shewanella violacea DSS12, Shewanella benthica DB21MT-2, Moritella yayanosii DB21MT-5, in biosynthesis and dietary uptake of PUFAs. These piezophilic bacteria were characterized by high abundance of unsaturated fatty acids (62-73% of total fatty acids). In particularly, polyunsaturated fatty acids (PUFA) were detected in all piezophiles examined, ranging from 8 to 27% of total fatty acids. M. japonica DSK1 produced 22:6n-3 (cis-4,7,10,13,16,19-docosahexaenoic acid, DHA), whereas the three Shewanella strains produced 20:5n-3 (cis-5,8,11,14,17-eicosapentaenoic acid, EPA) with trace amounts of DHA. The total concentrations of PLFA were higher in strains grown at low pressure (DSK1, 10 Megapascal or MPa, 26,983μ g/g dry wt cells; DSS12, 50 MPa, 23,986 μ g/g), and lower in strains grown at high pressure (DB6705, 85 MPa, 1,901μ g/g; DB21MT-2, 100 MPa, 3,014 μ g/g). When growth media were supplemented with arachidonic acid (AA; C20:4n-6), there was active uptake and cellular incorporation of AA in the hyperpiezophilic bacteria DB21MT-2 (14.7%) and DB21MT-5 (1.4%). No uptake was observed in DSS12. When cells were treated with antibiotic cerulenin, all three strains incorporated AA into cell membranes (13 to 19%). These results suggest that piezophilic bacteria can be an important contributor in producing and reworking of PUFAs in the deep sea, and that that caution must be exercised in using PUFAs in deducing sources of organic matter in the marine sediments.

Changes in zooplankton community, and seston and zooplankton fatty acid profiles at the freshwater/saltwater interface of the Chowan River, North Carolina

PubMed Central

Rinchard, Jacques; Kimmel, David G.

2017-01-01

The variability in zooplankton fatty acid composition may be an indicator of larval fish habitat quality as fatty acids are linked to fish larval growth and survival. We sampled an anadromous fish nursery, the Chowan River, during spring of 2013 in order to determine how the seston fatty acid composition varied in comparison with the zooplankton community composition and fatty acid composition during the period of anadromous larval fish residency. The seston fatty acid profiles showed no distinct pattern in relation to sampling time or location. The mesozooplankton community composition varied spatially and the fatty acid profiles were typical of freshwater species in April. The Chowan River experienced a saltwater intrusion event during May, which resulted in brackish water species dominating the zooplankton community and the fatty acid profile showed an increase in polyunsaturated fatty acids (PUFA), in particular eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). The saltwater intrusion event was followed by an influx of freshwater due to high precipitation levels in June. The zooplankton community composition once again became dominated by freshwater species and the fatty acid profiles shifted to reflect this change; however, EPA levels remained high, particularly in the lower river. We found correlations between the seston, microzooplankton and mesozooplankton fatty acid compositions. Salinity was the main factor correlated to the observed pattern in species composition, and fatty acid changes in the mesozooplankton. These data suggest that anadromous fish nursery habitat likely experiences considerable spatial variability in fatty acid profiles of zooplankton prey and that are correlated to seston community composition and hydrodynamic changes. Our results also suggest that sufficient prey density as well as a diverse fatty acid composition is present in the Chowan River to support larval fish production. PMID:28828262

Bacterial Diversity within the Extreme Arid Atacama Desert Soils of the Yungay Region, Chile

NASA Astrophysics Data System (ADS)

Connon, S. A.; Lester, E. D.; Shafaat, H. S.; Obenhuber, D. C.; Ponce, A.

2006-12-01

Surface and subsurface soil samples analyzed for this study were collected from the hyper-arid Yungay region of the Atacama Desert, Chile. This is the first report of microbial diversity from DNA extracted directly from these extremely desiccated soils. Our data shows that 94% of the 16S rRNA genes cloned from these soils belong to the Actinobacteria phylum. A 24-hour time course series showed a diurnal water activity (aw) cycle that peaked at 0.52 in the early predawn hours, and ranged from 0.08 0.01 during the day. All measured water activity values were below the level required for microbial growth or enzyme activity. Total organic carbon (TOC) levels in this region were just above the limits of detection and ranged from 220 660 μg/g of soil. Phospholipid fatty acid (PLFA) levels indicated cellular biomass ranging from 2 ×105 to 7 ×106 cell equivalents per gram of soil. The culturable counts were low with most samples showing no growth on standard plates of R2A medium; the highest single count was 47 colony forming units (CFU) per gram.

Bioremediation of petroleum hydrocarbon contaminated soil by Rhodobacter sphaeroides biofertilizer and plants.

PubMed

Jiao, Haihua; Luo, Jinxue; Zhang, Yiming; Xu, Shengjun; Bai, Zhihui; Huang, Zhanbin

2015-09-01

Bio-augmentation is a promising technique for remediation of polluted soils. This study aimed to evaluate the bio-augmentation effect of Rhodobacter sphaeroides biofertilizer (RBF) on the bioremediation of total petroleum hydrocarbons (TPH) contaminated soil. A greenhouse pot experiment was conducted over a period of 120 days, three methods for enhancing bio-augmentation were tested on TPH contaminated soils, including single addition RBF, planting, and combining of RBF and three crop species, such as wheat (W), cabbage (C) and spinach (S), respectively. The results demonstrated that the best removal of TPH from contaminated soil in the RBF bio-augmentation rhizosphere soils was found to be 46.2%, 65.4%, 67.5% for W+RBF, C+RBF, S+RBF rhizosphere soils respectively. RBF supply impacted on the microbial community diversity (phospholipid fatty acids, PLFA) and the activity of soil enzymes, such as dehydrogenase (DH), alkaline phosphatase (AP) and urease (UR). There were significant difference among the soil only containing crude oil (CK), W, C and S rhizosphere soils and RBF bio-augmentation soils. Moreover, the changes were significantly distinct depended on crops species. It was concluded that the RBF is a valuable material for improving effect of remediation of TPH polluted soils.

Intumescent composition, foamed product prepared therewith and process for making same

NASA Technical Reports Server (NTRS)

Riccitiello, S. R.; Parker, J. A. (Inventor)

1974-01-01

An intumescent composition and the foamed product prepared by heating the composition are provided. The composition comprises the reaction product of para-benzoquinone dioxime and a concentrated mineral acid such as sulfuric acid, phosphoric acid, and polyphosphoric acid. The composition is useful as an intumescent agent either by itself or when combined with other materials. A fire-resistant and heat-insulating composition is provided by heating the intumescent composition above its intumescent temperature.

The combined effects of urea application and simulated acid rain on soil acidification and microbial community structure.

PubMed

Liu, Xingmei; Zhou, Jian; Li, Wanlu; Xu, Jianming; Brookes, Philip C

2014-05-01

Our aim was to test the effects of simulated acid rain (SAR) at different pHs, when applied to fertilized and unfertilized soils, on the leaching of soil cations (K, Ca, Mg, Na) and Al. Their effects on soil pH, exchangeable H(+) and Al(3+) and microbial community structure were also determined. A Paleudalfs soil was incubated for 30 days, with and without an initial application of urea (200 mg N kg(-1)soil) as nitrogen (N) fertilizer. The soil was held in columns and leached with SAR at three pH levels. Six treatments were tested: SAR of pH 2.5, 4.0 and 5.6 leaching on unfertilized soil (T1, T2 and T3), and on soils fertilized with urea (T4, T5 and T6). Increasing acid inputs proportionally increased cation leaching in both unfertilized and fertilized soils. Urea application increased the initial Ca and Mg leaching, but had no effect on the total concentrations of Ca, Mg and K leached. There was no significant difference for the amount of Na leached between the different treatments. The SAR pH and urea application had significant effects on soil pH, exchangeable H(+) and Al(3+). Urea application, SAR treated with various pH, and the interactions between them all had significant impacts on total phospholipid fatty acids (PLFAs). The highest concentration of total PLFAs occurred in fertilized soils with SAR pH5.6 and the lowest in soils leached with the lowest SAR pH. Soils pretreated with urea then leached with SARs of pH 4.0 and 5.6 had larger total PLFA concentrations than soil without urea. Bacterial, fungal, actinomycete, Gram-negative and Gram-positive bacterial PLFAs had generally similar trends to total PLFAs.

Fatty acid compositions of triglycerides and free fatty acids in sebum depend on amount of triglycerides, and do not differ in presence or absence of acne vulgaris.

PubMed

Akaza, Narifumi; Akamatsu, Hirohiko; Numata, Shigeki; Matsusue, Miyuki; Mashima, Yasuo; Miyawaki, Masaaki; Yamada, Shunji; Yagami, Akiko; Nakata, Satoru; Matsunaga, Kayoko

2014-12-01

To clarify the influence of the fatty acid composition of sebum in acne vulgaris, we investigated the amounts and fatty acid compositions of triglycerides (TG) and free fatty acids (FFA), and the amounts of cutaneous superficial Propionibacterium acnes in acne patients and healthy subjects. The foreheads of 18 female patients, 10 male patients, 10 healthy females and 10 healthy males were studied in a Japanese population. There were significant differences in the amounts of sebum, TG and cutaneous superficial P. acnes, as well as the fatty acid compositions of TG and FFA between acne patients and healthy subjects in females. Their fatty acid compositions were correlated with the amount of TG with or without acne. It was clarified that the fatty acid compositions of TG and FFA depended on the amount of TG, and there were no differences in the fatty acid composition in the presence and absence of acne. © 2014 Japanese Dermatological Association.

Intumescent composition, foamed product prepared therewith, and process for making same

NASA Technical Reports Server (NTRS)

Riccitiello, S. R.; Parker, J. A. (Inventor)

1973-01-01

An intumescent composition and the foamed product prepared by heating are discussed wherein the composition comprises the reaction product of para-benzoquinone dioxime and a concentrated mineral acid such as sulfuric acid, phosphoric acid, and polyphosphoric acid. The composition is useful as an intumescent agent either by itself or when combined with other materials. A fire-resistant and heat-insulating composition is provided by heating the intumescent composition above its intumescent temperature.

Metabolic potential and community structure of endophytic and rhizosphere bacteria associated with the roots of the halophyte Aster tripolium L.

PubMed

Szymańska, Sonia; Płociniczak, Tomasz; Piotrowska-Seget, Zofia; Złoch, Michał; Ruppel, Silke; Hrynkiewicz, Katarzyna

2016-01-01

The submitted work assumes that the abundance and diversity of endophytic and rhizosphere microorganisms co-existing with the halophytic plant Aster tripolium L. growing in a salty meadow in the vicinity of a soda factory (central Poland) represent unique populations of cultivable bacterial strains. Endophytic and rhizosphere bacteria were (i) isolated and identified based on 16S rDNA sequences; (ii) screened for nifH and acdS genes; and (iii) analyzed based on selected metabolic properties. Moreover, total microbial biomass and community structures of the roots (endophytes), rhizosphere and soil were evaluated using a cultivation-independent technique (PLFA) to characterize plant-microbial interactions under natural salt conditions. The identification of the isolated strains showed domination by Gram-positive bacteria (mostly Bacillus spp.) both in the rhizosphere (90.9%) and roots (72.7%) of A. tripolium. Rhizosphere bacterial strains exhibited broader metabolic capacities, while endophytes exhibited higher specificities for metabolic activity. The PLFA analysis showed that the total bacterial biomass decreased in the following order (rhizosphere

[Relationship between the culture medium and the fatty acid composition of diphtheria and non-pathogenic corynebacteria].

PubMed

Vasiurenko, Z P; Siniak, K M

1977-04-01

The gasochromatic method was applied to the study of the cellular fatty acids composition in diphtheria and nonpathogenic corynebacteria (diphtheroids and psendo diptheria bacillus). Marked differences in the content of unsaturated fatty acids were revealed in them. Thus, palmito leic acid served the preponderant unsaturated fatty acid in Corynebacteria diphtheriae, and unsaturated fatty acids with 18 carbon atoms (octadeconoic and linoleic)--in nonpathogenic corynebacteria. The mentioned changes permit use this sign as differential. When grown on Loeffler's medium all the corynebacteria under study had a similar fatty acid composition characterized by the prevalence of unsaturated fatty acids with 18 carbon atoms. On the basis of studying the fatty acid spectrum of the nutrient media used it is supposed that one of the factors determining the revealed dependence of the corynebacterial fatty acid composition on the culture medium was the fatty acid composition of the latter.

A study of bone marrow and subcutaneous fatty acid composition in subjects of varying bone mineral density.

PubMed

Griffith, James F; Yeung, David K W; Ahuja, Anil T; Choy, Carol W Y; Mei, Wong Yin; Lam, Sherlock S L; Lam, T P; Chen, Zhen-Yu; Leung, Ping C

2009-06-01

Osteoporosis is associated with an increase in marrow fat. Fats, particularly polyunsaturated fats, either in co-cultures or diet, have been shown to significantly influence bone remodeling. Whether the increase in marrow fat seen in osteoporosis is also associated with a change in fatty acid composition is not known. This study was undertaken to investigate the fatty acid composition in subjects of varying bone mineral density (BMD). Samples of marrow fat and subcutaneous fat from 126 subjects (98 females, 34 males, mean age 69.7+/-10.5 years) undergoing orthopedic surgery were analyzed for fatty acid composition by gas chromatography. These results were correlated with BMD assessed by DXA. A total of 22 fatty acids were identified in marrow and subcutaneous fat. Significant differences in fatty acid composition existed between marrow and subcutaneous fat as well as between marrow fat samples obtained from the proximal femur and proximal tibia. Other than cis-7-hexadecenoic acid [C16:1 (n=9)] and docosanoic acid [C22:0], no difference in marrow fatty acid composition was evident between subject groups of varying BMD (normal, low bone mass, and osteoporosis). In conclusion, there exists a wide range of individual fatty acids in marrow fat. Marrow fatty acid composition differs from that of subcutaneous fat and varies between predominantly erythropoetic and fatty marrow sites. Other than cis-7-hexadecenoic acid [C16:1 (n=9)] and docosanoic acid [C22:0], no difference in marrow fatty acid composition was evident between subjects of varying BMD.

Methods of decontaminating surfaces and related compositions

DOEpatents

Demmer, Ricky L.; Crosby, Daniel; Norton, Christopher J.

2016-11-22

A composition of matter includes water, at least one acid, at least one surfactant, at least one fluoride salt, and ammonium nitrate. A method of decontaminating a surface includes exposing a surface to such a composition and removing the composition from the surface. Other compositions of matter include water, a fatty alcohol ether sulfate, nitrilotriacetic acid, at least one of hydrochloric acid and nitric acid, sodium fluoride, potassium fluoride, ammonium nitrate, and gelatin.

Phospholipid and fatty acid compositions of Rhizobium leguminosarum biovar trifolii ANU843 in relation to flavone-activated pSym nod gene expression.

PubMed

Orgambide, G G; Huang, Z H; Gage, D A; Dazzo, F B

1993-11-01

The phospholipid and associated fatty acid compositions of the bacterial symbiont of clover, Rhizobium leguminosarum biovar trifolii wild-type ANU843, was analyzed by two-dimensional silica thin-layer chromatography, fast atom bombardment-mass spectrometry, flame-ionization detection gas-liquid chromatography and combined gas-liquid chromatography/mass spectrometry. The phospholipid composition included phosphatidylethanolamine (15%), N-methylphosphatidylethanolamine (47%), N,N-dimethylphosphatidylethanolamine (9%), phosphatidylglycerol (19%), cardiolipin (5%) and phosphatidylcholine (2%). Fatty acid composition included predominantly cis-11-octadecenoic acid, lower levels of cis-9-hexadecenoic acid, hexadecanoic acid, 11-methyl-11-octadecenoic acid, octadecanoic acid, 11,12-methyleneoctadecanoic acid, eicosanoic acid and traces of branched, and di- and triunsaturated fatty acids. The influence of expression of the "nodulation" genes encoding symbiotic functions on the composition of these membrane lipids was examined in wild-type cells grown with or without the flavone inducer, 4',7-dihydroxyflavone and in mutated cells lacking the entire symbiotic plasmid where these genes reside, or containing single transposon insertions in selected nodulation genes. No significant changes in phospholipid or associated fatty acid compositions were detected by the above methods of analysis.

Microbial carbon turnover in the plant-rhizosphere-soil continuum

NASA Astrophysics Data System (ADS)

Malik, Ashish; Dannert, Helena; Griffiths, Robert; Thomson, Bruce; Gleixner, Gerd

2014-05-01

Soil microbial biomass contributes significantly to maintenance of soil organic matter (SOM). It is well known that biochemical fractions of soil microorganisms have varying turnover and therefore contribute differentially to soil C storage. Here we compare the turnover rates of different microbial biochemical fractions using a pulse chase 13CO2 plant labelling experiment. The isotope signal was temporally traced into rhizosphere soil microorganisms using the following biomarkers: DNA, RNA, fatty acids and chloroform fumigation extraction derived microbial biomass size classes. C flow into soil microbial functional groups was assessed through phospholipid and neutral lipid fatty acid (PLFA/NLFA) analyses. Highest 13C enrichment was seen in the low molecular weight (LMW) size class of microbial biomass (Δδ13C =151) and in nucleic acids (DNA: 38o RNA: 66) immediately after the pulse followed by a sharp drop. The amount of 13C in the high molecular weight (HMW) microbial biomass (17-81) and total fatty acids (32-54) was lower initially and stayed relatively steady over the 4 weeks experimental period. We found significant differences in turnover rates of different microbial biochemical and size fractions. We infer that LMW cytosolic soluble compounds are rapidly metabolized and linked to respiratory C fluxes, whereas mid-sized products of microbial degradation and HMW polymeric compounds have lower renewal rate in that order. The turnover of cell wall fatty acids was also very slow. DNA and RNA showed faster turnover rate; and as expected RNA renewal was the fastest due to its rapid production by active microorganisms independent of cell replication. 13C incorporation into different functional groups confirmed that mutualistic arbuscular mycorrhizal fungi rely on root C and are important in the initial plant C flux. We substantiated through measurements of isotope incorporation into bacterial RNA that rhizosphere bacteria are also important in the initial C conduit from plants. Other saprophytic fungi and bacteria show a delayed 13C incorporation pattern which could suggest secondary 13C assimilation often indicative of trophic interactions. Thus, different soil microbial biochemical fractions as well as functional groups show differential C turnover which could have implications on soil C storage.

Fate of microbial nitrogen, carbon, hydrolysable amino acids, monosaccharides, and fatty acids in sediment

NASA Astrophysics Data System (ADS)

Veuger, Bart; van Oevelen, Dick; Middelburg, Jack J.

2012-04-01

The fate of microbial carbon, nitrogen, hydrolysable amino acids (HAAs), monosaccharides, and fatty acids in sediment was investigated experimentally. The microbial community of a tidal flat sediment was labeled with 13C-enriched glucose and 15N-enriched ammonium, and sediment was incubated for up to 371 days. Analysis of total concentrations and 13C- and 15N content of bulk sediment, hydrolysable amino acids (including D-alanine), monosaccharides, total fatty acids (TFAs), and phospholipid-derived fatty acids (PLFAs) allowed us to trace the fate of microbial biomass and -detritus and the major biochemical groups therein (proteins, carbohydrates, and lipids) over intermediate time scales (weeks-months). Moreover, the unidentified fraction of the labeled material (i.e. not analyzed as HAA, FA, or carbohydrate) provided information on the formation and fate of molecularly uncharacterizable organic matter. Loss of 13C and 15N from the sediment was slow (half live of 433 days) which may have been due to the permanently anoxic conditions in the experiment. Loss rates for the different biochemical groups were also low with the following order of loss rate constants: PLFA > TFA > HAA > monosaccharides. The unidentified 13C-pool was rapidly formed (within days) and then decreased relatively slowly, resulting in a gradual relative accumulation of this pool over time. Degradation and microbial reworking of the labeled material resulted in subtle, yet consistent, diagenetic changes within the different biochemical groups. In the HAA pool, glycine, lysine, and proline were lost relatively slowly (i.e. best preserved) while there was no accumulation of D-alanine relative to L-alanine, indicating no relative accumulation of bacterial macromolecules rich in D-alanine. In the fatty acid pool, there was very little difference between PLFAs and TFAs, indicating a very similar lability of these pools. Differences between individual fatty acids included a relatively slow loss of i15:0, ai15:0 and 18:1ω7c which likely resulted from production of these bacterial fatty acids during bacterial reworking of the organic matter. Differences between loss rate constants for individual monosaccharides were not significant. An exception was ribose that was produced and lost relatively rapidly, which may be related to ribose being an important component of RNA. Losses of bulk 13C and 15N were closely coupled despite partly being present in different biochemicals and partly being derived from different microbial sources, indicating no selective preservation of either C or N during organic matter diagenesis.

Analysis of 2H-Evaporator Acid Cleaning Samples

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hay, M.; Diprete, D.; Edwards, T.

The 2H-Evaporator acid cleaning solution samples were analyzed by SRNL to determine a composition for the scale present in the evaporator before recent acid cleaning. Composite samples were formed from the solution samples from the two acid cleaning cycles. The solution composition was converted to a weight percent scale solids basis under an assumed chemical composition. The scale composition produced from the acid cleaning solution samples indicates a concentration of 6.85 wt% uranium. An upper bound, onesided 95% confidence interval on the weight percent uranium value may be given as 6.9 wt% + 1.645 × 0.596 wt% = 7.9 wt%.more » The comparison of the composition from the current acid cleaning solutions with the composition of recent scale samples along with the thermodynamic modeling results provides reasonable assurance that the sample results provide a good representation of the overall scale composition in the evaporator prior to acid cleaning. The small amount of scale solids dissolved in the 1.5 M nitric acid during the evaporator cleaning process likely produced only a small amount of precipitation based on modeling results and the visual appearance of the samples.« less

Drought and heat stress effects on soybean fatty acid composition and oil stability

USDA-ARS?s Scientific Manuscript database

Previous studies have shown that oil concentration and fatty acid profile (composition) change with genotype, environment (mainly heat and drought), and geographical location. The changes in fatty acid composition under these conditions affect fatty acid stability, creating a challenge to oil proces...

Label-free amino acid detection based on nanocomposites of graphene oxide hybridized with gold nanoparticles.

PubMed

Zhang, Qian; Zhang, Diming; Lu, Yanli; Xu, Gang; Yao, Yao; Li, Shuang; Liu, Qingjun

2016-03-15

Nanocomposites of graphene oxide and gold nanoparticles (GO/GNPs) were synthesized for label-free detections of amino acids. Interactions between the composites and amino acids were investigated by both naked-eye observation and optical absorption spectroscopy. The GO/GNPs composites displayed apparent color changes and absorption spectra changes in presences of amino acids including glutamate, aspartate, and cysteine. The interaction mechanisms of the composites and amino acids were discussed and explored with sulfhydryl groups and non-α-carboxylic groups on the amino acids. Sensing properties of the composites were tested, while pure gold particles were used as the control. The results suggested that the GO/GNPs composites had better linearity and stability in dose-dependent responses to the amino acids than those of the particles, especially in detections for acidic amino acids. Therefore, the nanocomposites platform can provide a convenient and efficient approach for label-free optical detections of important molecules such as amino acids. Copyright © 2015 Elsevier B.V. All rights reserved.

Changes in the fatty acid composition in bitter Lupinus species depend on the debittering process.

PubMed

Curti, Carolina A; Curti, Ramiro N; Bonini, Norberto; Ramón, Adriana N

2018-10-15

The evaluation of changes in the fatty acid composition in Lupinus species after the debittering process is crucial to determine their nutritional implications. The aim of this study was to evaluate changes in the fatty acid composition in Lupinus albus and L. mutabilis after the debittering process. Lupinus species showed different fatty acid compositions which changed depending on the debittering process applied. The debittering process changed the monounsaturated and polyunsaturated fatty acids in L. albus, whereas in L. mutabilis it changed the w-6/w-3 ratio. However, the total saturated fatty acid content remained stable in both species after the debittering process. The changes in L. albus were associated with the fatty acid desaturation and a conversion into unsaturated fatty acids, whereas in L. mutabilis with the lipid peroxidation by decreasing the linoleic acid content. Nutritional implications of these changes in the fatty acid composition are discussed. Copyright © 2018. Published by Elsevier Ltd.

Short-term carbon dynamics in a temperate heathland upon six years of exposure to elevated CO2 concentration, drought and warming: Evidence from an in-situ 13CO2 pulse-chase experiment

NASA Astrophysics Data System (ADS)

Ambus, P.; Reinsch, S.; Sárossy, Z.; Egsgaard, H.; Jakobsen, I.; Michelsen, A.; Schmidt, I.; Nielsen, P.

2013-12-01

An in-situ 13CO2 pulse-labeling experiment was carried out in a temperate heathland (8 oC MAT, 610 mm MAP) to study the impact on short-term carbon (C) allocation as affected by elevated CO2 concentration (+120 ppm), prolonged summer droughts (ca. -43 mm) and warming (+1 oC). The study was carried out six years after the climate treatments were initiated and took place in the early growing season in May in vegetation dominated by grasses, mainly Deschampsia flexuosa. Newly assimilated C (13C from the pulse-label) was traced into vegetation, soil and soil microorganisms and belowground respiration 1, 2 and 8 days after pulse-labeling. The importance of the microbial community in C utilization was investigated using 13C enrichment patterns in different microbial functional groups on the basis of phospholipid fatty acid (PLFA) profiles. Climate treatments did not affect microorganism abundance in soil or rhizosphere fractions in terms of total PLFA-C concentration. Elevated CO2 significantly reduced the abundance of gram-negative bacteria (17:0cy), but did not affect the abundance of decomposers (fungi and actinomycetes) in rhizosphere fractions. Drought favored the bacterial community in rhizosphere fractions whereas warming reduced the abundance of gram-negative bacteria (19:0cy) and changed the actinomycetes community (10Me16:0, 10Me18:0). Fastest and highest utilization of recently assimilated C was observed in rhizosphere associated gram-negative bacteria followed by gram-positive bacteria. The utilization of recently assimilated C by the microbial community was faster under elevated CO2 conditions compared to ambient. The 13C assimilation by green plant tissue and translocation to roots was significantly reduced by the extended summer drought. Under elevated CO2 conditions we observed an increased amount of 13C in the litter fraction. The assimilation of 13C by vegetation was not changed when the climate factors were applied in combination. The total amount of 13C lost by belowground respiration was not altered by the climatic manipulations. We conclude that six years of changed climatic conditions have affected the temporal and functional pattern of C utilization by the soil microorganisms towards increased C cycling mainly caused by bacterial activity. This change may potentially alter the ecosystem C balance. Meanwhile, the short-term C balance was not affected by six years of environmental changes, which suggests substantial ecosystem resilience.

Amino acid and proximate composition of fish bone gelatin from different warm-water species: A comparative study

NASA Astrophysics Data System (ADS)

Atma, Y.

2017-03-01

Research on fish bone gelatin has been increased in the last decade. The quality of gelatin depends on its physicochemical properties. Fish bone gelatin from warm-water fishes has a superior amino acid composition than cold-water fishes. The composition of amino acid can determine the strength and stability of gelatin. Thus, it is important to analyze the composition of amino acid as well as proximate composition for potential gelatin material. The warm water fish species used in this study were Grass carp, Pangasius catfish, Catfish, Lizard fish, Tiger-toothed croaker, Pink perch, Red snapper, Brown spotted grouper, and King weakfish. There werre five dominant amino acid in fish bone gelatin including glycine (21.2-36.7%), proline (8.7-11.7%), hydroxyproline (5.3-9.6%), alanine (8.48-12.9%), and glutamic acid (7.23-10.15%). Different warm-water species has some differences in amino acid composition. The proximate composition showed that fishbone gelatin from Pangasius catfish has the highest protein content. The water composition of all fishbone gelatin was well suited to the standard. Meanwhile, based on ash content, only gelatin from gelatin Pangasius catfish met the standard for food industries.

Proximate composition, amino acid and fatty acid composition of fish maws.

PubMed

Wen, Jing; Zeng, Ling; Xu, Youhou; Sun, Yulin; Chen, Ziming; Fan, Sigang

2016-01-01

Fish maws are commonly recommended and consumed in Asia over many centuries because it is believed to have some traditional medical properties. This study highlights and provides new information on the proximate composition, amino acid and fatty acid composition of fish maws of Cynoscion acoupa, Congresox talabonoides and Sciades proops. The results indicated that fish maws were excellent protein sources and low in fat content. The proteins in fish maws were rich in functional amino acids (FAAs) and the ratio of FAAs and total amino acids in fish maws ranged from 0.68 to 0.69. Among species, croaker C. acoupa contained the most polyunsaturated fatty acids, arachidonic acid, docosahexaenoic acid and eicosapntemacnioc acid, showing the lowest value of index of atherogenicity and index of thrombogenicity, showing the highest value of hypocholesterolemic/hypercholesterolemic ratio, which is the most desirable.

Serum Paraoxonase 1 Activity Is Associated with Fatty Acid Composition of High Density Lipoprotein

PubMed Central

Boshtam, Maryam; Pourfarzam, Morteza; Ani, Mohsen; Naderi, Gholam Ali; Basati, Gholam; Mansourian, Marjan; Dinani, Narges Jafari; Asgary, Seddigheh; Abdi, Soheila

2013-01-01

Introduction. Cardioprotective effect of high density lipoprotein (HDL) is, in part, dependent on its related enzyme, paraoxonase 1 (PON1). Fatty acid composition of HDL could affect its size and structure. On the other hand, PON1 activity is directly related to the structure of HDL. This study was designed to investigate the association between serum PON1 activity and fatty acid composition of HDL in healthy men. Methods. One hundred and forty healthy men participated in this research. HDL was separated by sequential ultracentrifugation, and its fatty acid composition was analyzed by gas chromatography. PON1 activity was measured spectrophotometrically using paraxon as substrate. Results. Serum PON1 activity was directly correlated with the amount of stearic acid and dihomo-gamma-linolenic acid (DGLA). PON1/HDL-C was directly correlated with the amount of miristic acid, stearic acid, and DGLA and was inversely correlated with total amount of ω6 fatty acids of HDL. Conclusion. The fatty acid composition of HDL could affect the activity of its associated enzyme, PON1. As dietary fats are the major determinants of serum lipids and lipoprotein composition, consuming some special dietary fatty acids may improve the activity of PON1 and thereby have beneficial effects on health. PMID:24167374

Serum paraoxonase 1 activity is associated with fatty acid composition of high density lipoprotein.

PubMed

Boshtam, Maryam; Razavi, Amirnader Emami; Pourfarzam, Morteza; Ani, Mohsen; Naderi, Gholam Ali; Basati, Gholam; Mansourian, Marjan; Dinani, Narges Jafari; Asgary, Seddigheh; Abdi, Soheila

2013-01-01

Cardioprotective effect of high density lipoprotein (HDL) is, in part, dependent on its related enzyme, paraoxonase 1 (PON1). Fatty acid composition of HDL could affect its size and structure. On the other hand, PON1 activity is directly related to the structure of HDL. This study was designed to investigate the association between serum PON1 activity and fatty acid composition of HDL in healthy men. One hundred and forty healthy men participated in this research. HDL was separated by sequential ultracentrifugation, and its fatty acid composition was analyzed by gas chromatography. PON1 activity was measured spectrophotometrically using paraxon as substrate. Serum PON1 activity was directly correlated with the amount of stearic acid and dihomo-gamma-linolenic acid (DGLA). PON1/HDL-C was directly correlated with the amount of miristic acid, stearic acid, and DGLA and was inversely correlated with total amount of ω 6 fatty acids of HDL. The fatty acid composition of HDL could affect the activity of its associated enzyme, PON1. As dietary fats are the major determinants of serum lipids and lipoprotein composition, consuming some special dietary fatty acids may improve the activity of PON1 and thereby have beneficial effects on health.

The effects of season on fatty acid composition and ω3/ω6 ratios of northern pike ( Esox lucius L., 1758) muscle lipids

NASA Astrophysics Data System (ADS)

Mert, Ramazan; Bulut, Sait; Konuk, Muhsin

2015-01-01

In the present study, the effects of season on fatty acid composition, total lipids, and ω3/ω6 ratios of northern pike muscle lipids in Kizilirmak River (Kirikkale, Turkey) were investigated. A total of 35 different fatty acids were determined in gas chromatography. Among these, palmitic, oleic, and palmitoleic acids had the highest proportion. The main polyunsaturated fatty acids (PUFAs) were found to be docosahexaenoic acid, eicosapentaenoic acid, and arachidonic acid. There were more PUFAs than monounsaturated fatty acids (MUFA) in all seasons. Similarly, the percentages of ω3 fatty acids were higher than those of total ω6 fatty acids in the fatty acid composition. ω3/ω6 ratios were calculated as 1.53, 1.32, 1.97, and 1.71 in spring, summer, autumn and winter, respectively. Overall, we found that the fatty acid composition and ω3/ω6 fatty acid ratio in the muscle of northern pike were significantly influenced by season.

Fatty acid and sn-2 fatty acid composition in human milk from Granada (Spain) and in infant formulas.

PubMed

López-López, A; López-Sabater, M C; Campoy-Folgoso, C; Rivero-Urgell, M; Castellote-Bargalló, A I

2002-12-01

To investigate differences in fatty acid and sn-2 fatty acid composition in colostrum, transitional and mature human milk, and in term infant formulas. Departament de Nutrició i Bromatologia, University of Barcelona, Spain and University Hospital of Granada, Spain. One-hundred and twenty mothers and 11 available types of infant formulas for term infants. We analysed the fatty acid composition of colostrum (n=40), transitional milk (n=40), mature milk (n=40) and 11 infant formulas. We also analysed the fatty acid composition at sn-2 position in colostrum (n=12), transitional milk (n=12), mature milk (n=12), and the 11 infant formulas. Human milk in Spain had low saturated fatty acids, high monounsaturated fatty acids and high linolenic acid. Infant formulas and mature human milk had similar fatty acid composition. In mature milk, palmitic acid was preferentially esterified at the sn-2 position (86.25%), and oleic and linoleic acids were predominantly esterified at the sn-1,3 positions (12.22 and 22.27%, respectively, in the sn-2 position). In infant formulas, palmitic acid was preferentially esterified at the sn-1,3 positions and oleic and linoleic acids had higher percentages at the sn-2 position than they do in human milk. Fatty acid composition of human milk in Spain seems to reflect the Mediterranean dietary habits of mothers. Infant formulas resemble the fatty acid profile of human milk, but the distribution of fatty acids at the sn-2 position is markedly different.

Environmental and Chemical Aging of Fatty-Acid-Based Vinyl Ester Composites

DTIC Science & Technology

2011-04-01

Environmental and Chemical Aging of Fatty- Acid -Based Vinyl Ester Composites by Steven E. Boyd and John J. La Scala ARL-TR-5523 April...2011 Environmental and Chemical Aging of Fatty- Acid -Based Vinyl Ester Composites Steven E. Boyd and John J. La Scala Weapons and Materials...COVERED (From - To) October 2009–September 2010 4. TITLE AND SUBTITLE Environmental and Chemical Aging of Fatty- Acid -Based Vinyl Ester Composites

Stable Isotopic Tracking of Autocthonous Carbon in Two Contrasting Ozark Streams

NASA Astrophysics Data System (ADS)

Ziegler, S.; Brisco-Townsend, S.

2005-05-01

The central role of microbes in biogeochemical processes makes the identification of carbon (C) sources fueling microorganisms critical to our understanding of stream ecosystems. The δ13C of biofilm phospholipid fatty acids (δ13CBPLFA) were determined in experiments conducted from July 2002 through July 2003 using 13C-labeled bicarbonate to track autochthonous C in two streams. In Moore Creek (MC), an agricultural stream, and Huey Hollow (HH), a forested stream, dissolved organic carbon (DOC) was released in light incubations during all seasons and represented >10% biofilm net primary production. The DOC from light incubations was enriched in 13C relative to DOC from dark incubations suggesting algal exudates were a major source of the DOC. The δ13CBPLFA suggest that 13C enriched exudates were not utilized by heterotrophic bacterial components in MC. Autotrophic PLFA from light incubations were more enriched in 13C while heterotrophic bacterial δ13CBPLFA were similar between light and dark incubations. By contrast, both heterotrophic and autotrophic biomarkers were significantly enriched in 13C in light incubations relative to dark incubations conducted in spring and summer in HH. Results suggest the exchange of C between autotrophic and heterotrophic components of biofilm communities differs between nutrient-enriched and depleted streams.

Tracing C Fluxes From Leaf Litter To Microbial Respired CO2 And Specific Soil Compounds

NASA Astrophysics Data System (ADS)

Rubino, M.; Lubritto, C.; D'Onofrio, A.; Gleixner, G.; Terrasi, F.; Cotrufo, F. M.

2004-12-01

Despite litter decomposition is one of the major process controlling soil C stores and nutrient cycling, yet C dynamics during litter decay are poorly understood and quantified. Here we report the results of a laboratory experiment where 13C depleted leaf litter was incubated on a 13C enriched soil with the aims to: i) partition the C loss during litter decay into microbial respired-CO2 and C input into the soil; ii) identify the soil compounds where litter derived C is retained; iii) assess whether litter quality is a determinant of both the above processes. Three 13C-depleted leaf litter(delta13C ca. -43), differing in their degradability, were incubated on C4 soil (delta13C ca. -18) under laboratory controlled conditions for 8 months, with litter respiration and delta13C-CO2 being measured at regular intervals. At harvest, Compound Specific Isotope Analyses was performed on soil and litter samples in order to follow the fate of litter-derived C compounds in the various pools of SOMƒn The delta13C of soils carbohydrates, alkanes and Phospho Lipids Fatty Acids (PLFA) were measured, and the mixing model approach used to quantify the contribution of litter derived C to the specific compounds.

Quality of fresh organic matter affects priming of soil organic matter and substrate utilization patterns of microbes

PubMed Central

Wang, Hui; Boutton, Thomas W.; Xu, Wenhua; Hu, Guoqing; Jiang, Ping; Bai, Edith

2015-01-01

Changes in biogeochemical cycles and the climate system due to human activities are expected to change the quantity and quality of plant litter inputs to soils. How changing quality of fresh organic matter (FOM) might influence the priming effect (PE) on soil organic matter (SOM) mineralization is still under debate. Here we determined the PE induced by two 13C-labeled FOMs with contrasting nutritional quality (leaf vs. stalk of Zea mays L.). Soils from two different forest types yielded consistent results: soils amended with leaf tissue switched faster from negative PE to positive PE due to greater microbial growth compared to soils amended with stalks. However, after 16 d of incubation, soils amended with stalks had a higher PE than those amended with leaf. Phospholipid fatty acid (PLFA) results suggested that microbial demand for carbon and other nutrients was one of the major determinants of the PE observed. Therefore, consideration of both microbial demands for nutrients and FOM supply simultaneously is essential to understand the underlying mechanisms of PE. Our study provided evidence that changes in FOM quality could affect microbial utilization of substrate and PE on SOM mineralization, which may exacerbate global warming problems under future climate change. PMID:25960162

Microbial communities in liquid and fiber fractions of food waste digestates are differentially resistant to inhibition by ammonia.

PubMed

Peng, Wei; Lü, Fan; Shao, Liming; He, Pinjing

2015-04-01

The effect of different concentrations of ammonia (1.0-7.0 g/L) during mesophilic anaerobic digestion with fiber or liquid digestate as inoculum was examined. Evolution of microbial community within fiber and liquid digestates was quantitatively assessed by the intact lipid analysis methods and qualitatively by DNA fingerprint methods in order to determine their resistance to ammonia inhibition. The results showed that an increased level of total ammonia nitrogen prolonged the lag phase of fiber digestates while reduced the metabolic rate of liquid digestates. Fiber digestates had 19.6-50.9-fold higher concentrations of phospholipid fatty acids (PLFA) compared to liquid digestates, whereas concentrations of phospholipid ether lipids (PLEL) in the fiber digestates were only 2.91-17.6-fold higher compared to liquid digestates. Although the cell concentration in liquid fraction was far lower than that in the fiber one, the ammonia-resistant ability and the methanization efficiency of the liquid digestate was superior to the fiber digestate. The bacterial profiles were affected more by the type of digestate inoculum compared to the concentration of ammonia. Principal component analysis indicated that the lipids technique was superior to the DNA technique for bacterial quantification but detected less archaeal diversity.

Quality of fresh organic matter affects priming of soil organic matter and substrate utilization patterns of microbes.

PubMed

Wang, Hui; Boutton, Thomas W; Xu, Wenhua; Hu, Guoqing; Jiang, Ping; Bai, Edith

2015-05-11

Changes in biogeochemical cycles and the climate system due to human activities are expected to change the quantity and quality of plant litter inputs to soils. How changing quality of fresh organic matter (FOM) might influence the priming effect (PE) on soil organic matter (SOM) mineralization is still under debate. Here we determined the PE induced by two (13)C-labeled FOMs with contrasting nutritional quality (leaf vs. stalk of Zea mays L.). Soils from two different forest types yielded consistent results: soils amended with leaf tissue switched faster from negative PE to positive PE due to greater microbial growth compared to soils amended with stalks. However, after 16 d of incubation, soils amended with stalks had a higher PE than those amended with leaf. Phospholipid fatty acid (PLFA) results suggested that microbial demand for carbon and other nutrients was one of the major determinants of the PE observed. Therefore, consideration of both microbial demands for nutrients and FOM supply simultaneously is essential to understand the underlying mechanisms of PE. Our study provided evidence that changes in FOM quality could affect microbial utilization of substrate and PE on SOM mineralization, which may exacerbate global warming problems under future climate change.

Ancient Soils in a Sunburnt Country: Nutrient and Carbon Distributions in an Australian Dryland River System

NASA Astrophysics Data System (ADS)

McIntyre, R. E.; Grierson, P. F.; Adams, M. A.

2005-05-01

Riparian systems are hotspots in dryland landscapes for nutrient supply and transformation. Biogeochemical fluxes in riparian systems are closely coupled to hydrological flowpaths, which, in dryland regions, are characterised by catastrophic flooding and long periods of erratic or no flow. Re-wetting of soils stimulates soil microbial processes that drive mineralization of nutrients necessary for plant growth. We present here the first data of a 3-year research project investigating biogeochemical processes in riparian systems in the semi-arid Pilbara region of Western Australia. Spatial patterns of nitrogen, phosphorus and carbon were closely related to topographic zone (across floodplain and channels) and vegetation type. NO3- and PCi concentrations were four-fold higher in channel, bank and riparian soils than in soils of floodplain and riparian-floodplain transition zones. Nitrogen distribution was highly heterogeneous in riparian soils (NO3- CV=102%, NH4+ CV=84%) while phosphorus was particularly heterogeneous in floodplain soils (PCi CV=153%, PCo CV=266%), in comparison to other zones. Phospholipid fatty acid (PLFA) and enzymatic profiles will be used to assess microbial functional groups, combined with mineralisation experiments and stable isotope studies (15N and 13C). These data will improve understanding of biogeochemical cycling in dryland riparian systems, and contribute to improved regional management of water resources.

Quality of fresh organic matter affects priming of soil organic matter and substrate utilization patterns of microbes

NASA Astrophysics Data System (ADS)

Wang, Hui; Boutton, Thomas W.; Xu, Wenhua; Hu, Guoqing; Jiang, Ping; Bai, Edith

2015-05-01

Changes in biogeochemical cycles and the climate system due to human activities are expected to change the quantity and quality of plant litter inputs to soils. How changing quality of fresh organic matter (FOM) might influence the priming effect (PE) on soil organic matter (SOM) mineralization is still under debate. Here we determined the PE induced by two 13C-labeled FOMs with contrasting nutritional quality (leaf vs. stalk of Zea mays L.). Soils from two different forest types yielded consistent results: soils amended with leaf tissue switched faster from negative PE to positive PE due to greater microbial growth compared to soils amended with stalks. However, after 16 d of incubation, soils amended with stalks had a higher PE than those amended with leaf. Phospholipid fatty acid (PLFA) results suggested that microbial demand for carbon and other nutrients was one of the major determinants of the PE observed. Therefore, consideration of both microbial demands for nutrients and FOM supply simultaneously is essential to understand the underlying mechanisms of PE. Our study provided evidence that changes in FOM quality could affect microbial utilization of substrate and PE on SOM mineralization, which may exacerbate global warming problems under future climate change.

Fatty acid composition of spermatozoa is associated with BMI and with semen quality.

PubMed

Andersen, J M; Rønning, P O; Herning, H; Bekken, S D; Haugen, T B; Witczak, O

2016-09-01

High body mass index (BMI) is negatively associated with semen quality. In addition, the composition of fatty acids of spermatozoa has been shown to be important for their function. The aim of the study was to examine the association between BMI and the composition of spermatozoa fatty acids in men spanning a broad BMI range. We also analysed the relation between fatty acid composition of spermatozoa and semen characteristics, and the relationship between serum fatty acids and spermatozoa fatty acids. One hundred forty-four men with unknown fertility status were recruited from the general population, from couples with identified female infertility and from morbid obesity centres. Standard semen analysis (WHO) and sperm DNA integrity (DFI) analysis were performed. Fatty acid compositions were assessed by gas chromatography. When adjusted for possible confounders, BMI was negatively associated with levels of sperm docosahexaenoic acid (DHA) (p < 0.001) and palmitic acid (p < 0.001). The amount of sperm DHA correlated positively with total sperm count (r = 0.482), sperm concentration (r = 0.469), sperm vitality (r = 0.354), progressive sperm motility (r = 0.431) and normal sperm morphology (r = 0.265). A negative association was seen between DHA levels and DNA fragmentation index (r = -0.247). Levels of spermatozoa palmitic acid correlated positively with total sperm count (r = 0.227), while levels of linoleic acid correlated negatively (r = -0.254). When adjusted for possible confounders, only the levels of arachidonic acid showed positive correlation between spermatozoa and serum phospholipids (r = 0.262). Changes in the fatty acid composition of spermatozoa could be one of the mechanisms underlying the negative association between BMI and semen quality. The relationship between fatty acids of spermatozoa and serum phospholipids was minor, which indicates that BMI affects fatty acid composition of spermatozoa through regulation of fatty acid metabolism in the testis. The role of dietary intake of fatty acids on the spermatozoa fatty acid composition remains to be elucidated. © 2016 American Society of Andrology and European Academy of Andrology.

Surface roughness of composite resins subjected to hydrochloric acid.

PubMed

Roque, Ana Carolina Cabral; Bohner, Lauren Oliveira Lima; de Godoi, Ana Paula Terossi; Colucci, Vivian; Corona, Silmara Aparecida Milori; Catirse, Alma Blásida Concepción Elizaur Benitez

2015-01-01

The purpose of this study was to determine the influence of hydrochloric acid on surface roughness of composite resins subjected to brushing. Sixty samples measuring 2 mm thick x 6 mm diameter were prepared and used as experimental units. The study presented a 3x2 factorial design, in which the factors were composite resin (n=20), at 3 levels: microhybrid composite (Z100), nanofilled composite (FiltekTM Supreme), nanohybrid composite (Ice), and acid challenge (n=10) at 2 levels: absence and presence. Acid challenge was performed by immersion of specimens in hydrochloric acid (pH 1.2) for 1 min, 4 times per day for 7 days. The specimens not subjected to acid challenge were stored in 15 mL of artificial saliva at 37 oC. Afterwards, all specimens were submitted to abrasive challenge by a brushing cycle performed with a 200 g weight at a speed of 356 rpm, totaling 17.8 cycles. Surface roughness measurements (Ra) were performed and analyzed by ANOVA and Tukey test (p≤0.05). Surface roughness values were higher in the presence (1.07±0.24) as compared with the absence of hydrochloric acid (0.72±0.04). Surface roughness values were higher for microhybrid (1.01±0.27) compared with nanofilled (0.68 ±0.09) and nanohybrid (0.48±0.15) composites when the specimens were not subjects to acid challenge. In the presence of hydrochloric acid, microhybrid (1.26±0.28) and nanofilled (1.18±0,30) composites presents higher surface roughness values compared with nanohybrid (0.77±0.15). The hydrochloric acid affected the surface roughness of composite resin subjected to brushing.

Tree specie effects on soil microbial community composition and greenhouse gases emissions in a Mediterranean ecotone forest

NASA Astrophysics Data System (ADS)

Fernandez, Maria Jose; Ortiz, Carlos; Kitzler, Barbara; Curiel, Jorge; Rubio, Agustin

2016-04-01

Over recent decades in the Iberian Peninsula, altitudinal shifts from Pinus sylvestris L. to Quercus pyrenaica Willd species has been observed as a consequence of Global Change, meaning changes in temperature, precipitation, land use and forestry. The forest conversion from pine to oak can alter the litter quality and quantity provided to the soil and thereby the soil microbial community composition and functioning. Since soil microbiota plays an important role in organic matter decomposition, and this in turn is key in biogeochemical cycles and forest ecosystems productivity, the rate in which forests produce and consume greenhouse gases can be also affected by changes in forest composition. In other words, changes in litter decomposition will ultimately affect downstream carbon and nitrogen dynamics although this impact is uncertain. In order to predict changes in carbon and nitrogen stocks in Global Change scenarios, it is necessary to deepen the impact of vegetation changes on soil microbial communities, litter decomposition dynamics (priming effect) and the underlying interactions between these factors. To test this, we conducted a full-factorial transplant microcosms experiment mixing both fresh soils and litter from Pyrenean oak, Scots pine and mixed stands collected inside their transitional area in Central Spain. The microcosms consisted in soil cylinders inside Kilner jars used as chambers inside an incubator. In this experiment, we investigated how and to what extent the addition of litter with different quality (needles, oak leaves and mixed needles-leaves) to soil inoculums with contrasting soil microbiota impact on (i) soil CO2, NO, N2O and CH4 efflux rates, (ii) total organic carbon and nitrogen and (iii) dissolved organic carbon and nitrogen. Furthermore, we assessed if these responses were controlled by changes in the microbial community structure using the PLFA analyses prior and after the incubation period of 54 days.

The preparations of novel cellulose/phenylboronic acid composite intelligent bio-hydrogel and its glucose, pH-responsive behaviors.

PubMed

Peng, Huafeng; Ning, Xiaoyu; Wei, Gang; Wang, Shaopeng; Dai, Guoliang; Ju, Anqi

2018-09-01

Novel intelligent cellulose/4-vinyl-phenylboronic acid (VPBA) composite bio-hydrogels with glucose and pH-responsiveness were successfully prepared via electron beam irradiation technology at room temperature. The composites were characterized by Fourier transform infrared spectrum (FT-IR) and X-ray photoelectron spectroscopy (XPS). The electron beam irradiation results in the appearance of carbonyl in the polymerization of 4-ethenyl-phenylboronic acid, grafting and cross linking reaction in composites, and a novel composite hydrogel was formed between the poly-4-ethenyl-phenylboronic acid and cellulose matrix. By means of the incorporation of phenylboronic acid groups, the composite hydrogels with pH and glucose responsive properties was produced, and glucose responsive properties were investigated by the self-regulation of insulin release of composite hydrogel through a serial glucose solution with different concentrations, which is having great potential applications in many fields. Copyright © 2018 Elsevier Ltd. All rights reserved.

Microbiology, Redox and Contaminat Fate in the Grindsted Landfill Leachate Plume - A Summary of 25 Years of work

NASA Astrophysics Data System (ADS)

Christensen, T. H.

2001-05-01

The contamination by leachate of the upper aquifer at the Grindsted Landfill (Denmark) stretches about 300 m downgradient from the landfill. The plume has been described with respect to water chemistry, sediment chemistry, pollutant distribution, microbial counts, PLFA and redox rates determined by unamended bioassays. This presentation summaries the findings and discusses unanswered questions. The landfill was active from 1930 to the mid 1970 and has no engineered leachate collection system. Leachate from municipal as well as from industrial waste has entered the aquifer for more than thirty years. The redox conditions change from strongly anaerobic (methanogenic, sulfate reducing, iron reducing) close to the landfill over manganese reduction and denitrification to aerobic conditions in the outskirts of the plume The redox conditions were determined from groundwater sample composition, hydrogen concentrations and sediment chemistry. The plume showed strong attenuation of aromatic compounds within the first 100 m downgradient of the landfill. Degradation experiments (batch, in-situ testers, long term field injection experiments) could not fully document degradation of all the compounds. MPN-measurements of methanogens, sulfate-reducers, iron-reducers, manganese-reducers and denitrifiers showed abundance of all groups with a slight trend with the redox conditions. PLFA measurements did not provide much insight into the microbial populations of the plume, but confirmed some previous observations. Bioassays gave estimates of the rates of the various redox processes, but showed for some samples more simultaneous redox processes. More than 25 years of work has been put into the Grindsted Landfill leachate plume. References Bjerg, P.L., Rugge, K., Cortsen, J., Nielsen, P.H. & Christensen, T.H. (1999): Degradation of aromatic and chlorinated aliphatic hydrocarbons in the anaerobic part of the Grindsted Landfill leachate plume: In situ microcosm and laboratory batch experiments. Ground Water, 37, 113-121. Bjerg, P.L., Rugge, K., Pedersen, J.K. & Christensen, T.H. (1995): Distribution of redox sensitive groundwater quality parameters downgradient of a landfill (Grindsted, Denmark). Environmental Science and Technology, 29, 1387-1394. Heron, G., Bjerg, P.L., Gravesen, P., Ludvigsen, L. & Christensen, T.H. (1998): Geology and sediment geochemistry of a landfill leachate contaminated aquifer (Grindsted, Denmark). Journal of Contaminant Hydrology, 29, 301-317. Jakobsen, R., Albrechtsen, H.-J., Rasmussen, M., Bay, H., Bjerg, P.L. & Christensen, T.H. (1998): H2 concentrations in a landfill leachate plume (Grindsted, Denmark): In situ energetics of terminal electron acceptor processes. Environmental Science and Technology, 32, 2142-2148. Ludvigsen, L., Albrechtsen, H.-J., Heron, G., Bjerg, P.L. & Christensen, T.H. (1998): Anaerobic microbial redox processes in a landfill leachate contaminated aquifer (Grindsted, Denmark). Journal of Contaminant Hydrology, 33, 273-291. Ludvigsen, L., Albrechtsen, H.-J., Ringelberg, D., Ekelund, F. & Christensen, T.H. (1999): Distribution and composition of microbial populations in a landfill leachate contaminated aquifer (Grindsted, Denmark). Microbial Ecology, 37, (3), 197-207. Rugge, K., Bjerg, P.L. & Christensen, T.H. (1995): Distribution of organic compounds from municipal solid waste in the groundwater downgradient of a landfill (Grindsted, Denmark). Environmental Science and Technology, 29, 1395-1400.

Artificial Root Exudate System (ARES): a field approach to simulate tree root exudation in soils

NASA Astrophysics Data System (ADS)

Lopez-Sangil, Luis; Estradera-Gumbau, Eduard; George, Charles; Sayer, Emma

2016-04-01

The exudation of labile solutes by fine roots represents an important strategy for plants to promote soil nutrient availability in terrestrial ecosystems. Compounds exuded by roots (mainly sugars, carboxylic and amino acids) provide energy to soil microbes, thus priming the mineralization of soil organic matter (SOM) and the consequent release of inorganic nutrients into the rhizosphere. Studies in several forest ecosystems suggest that tree root exudates represent 1 to 10% of the total photoassimilated C, with exudation rates increasing markedly under elevated CO2 scenarios. Despite their importance in ecosystem functioning, we know little about how tree root exudation affect soil carbon dynamics in situ. This is mainly because there has been no viable method to experimentally control inputs of root exudates at field scale. Here, I present a method to apply artificial root exudates below the soil surface in small field plots. The artificial root exudate system (ARES) consists of a water container with a mixture of labile carbon solutes (mimicking tree root exudate rates and composition), which feeds a system of drip-tips covering an area of 1 m2. The tips are evenly distributed every 20 cm and inserted 4-cm into the soil with minimal disturbance. The system is regulated by a mechanical timer, such that artificial root exudate solution can be applied at frequent, regular daily intervals. We tested ARES from April to September 2015 (growing season) within a leaf-litter manipulation experiment ongoing in temperate deciduous woodland in the UK. Soil respiration was measured monthly, and soil samples were taken at the end of the growing season for PLFA, enzymatic activity and nutrient analyses. First results show a very rapid mineralization of the root exudate compounds and, interestingly, long-term increases in SOM respiration, with negligible effects on soil moisture levels. Large positive priming effects (2.5-fold increase in soil respiration during the growing season) were observed in absence of aboveground forest litter, with lower or no priming when the litter was present. Preliminary results show that soil microbial community is also significantly affected by ARES.

21 CFR 357.210 - Cholecystokinetic active ingredients.

Code of Federal Regulations, 2010 CFR

2010-04-01

... a melting point of 41 to 43.5 °C, an iodine value of 65 to 69, and a fatty acid composition as follows: Fatty acid Percent composition Myristic acid 0.1 Palmitic acid 10.0 Palmitoleic acid 0.1 Stearic acid 13.5 Oleic acid 72.0 Linoleic acid 3.8 Linolenic acid 0.1 Arachidic acid 0.5 Behenic acid 0.2 [54...

21 CFR 357.210 - Cholecystokinetic active ingredients.

Code of Federal Regulations, 2011 CFR

2011-04-01

... a melting point of 41 to 43.5 °C, an iodine value of 65 to 69, and a fatty acid composition as follows: Fatty acid Percent composition Myristic acid 0.1 Palmitic acid 10.0 Palmitoleic acid 0.1 Stearic acid 13.5 Oleic acid 72.0 Linoleic acid 3.8 Linolenic acid 0.1 Arachidic acid 0.5 Behenic acid 0.2 [54...

Erythrocyte linoleic acid, but not oleic acid, is associated with improvements in body composition in men and women.

PubMed

Belury, Martha A; Cole, Rachel M; Bailey, Brittney E; Ke, Jia-Yu; Andridge, Rebecca R; Kiecolt-Glaser, Janice K

2016-05-01

Supplementation with linoleic acid (LA; 18:2Ω6)-rich oils increases lean mass and decreases trunk adipose mass in people. Erythrocyte fatty acids reflect the dietary pattern of fatty acid intake and endogenous metabolism of fatty acids. The aim of this study is to determine the relationship of erythrocyte LA, with aspects of body composition, insulin resistance, and inflammation. Additionally, we tested for relationships of oleic acid (OA) and the sum of long chain omega-three fatty acids (LC-Ω3-SUM), on the same outcomes. Men and women (N = 139) were evaluated for body composition, insulin resistance, and serum inflammatory markers, IL-6, and c-reactive protein (CRP) and erythrocyte fatty acid composition after an overnight fast. LA was positively related to appendicular lean mass/body mass index and inversely related to trunk adipose mass. Additionally, LA was inversely related to insulin resistance and IL-6. While there was an inverse relationship between OA or LC-Ω3-SUM with markers of inflammation, there were no relationships between OA or LC-Ω3-SUM with body composition or HOMA-IR. Higher erythrocyte LA was associated with improved body composition, insulin resistance, and inflammation. Erythrocyte OA or LC-Ω3-SUM was unrelated to body composition and insulin resistance. There is much controversy about whether all unsaturated fats have the same benefits for metabolic syndrome and weight gain. We sought to test the strength of the relationships between three unsaturated fatty acid in erythrocytes with measurements of body composition, metabolism, and inflammation in healthy adults. Linoleic acid, but not oleic acid or the sum of long-chain omega 3 fatty acids (w3), was associated with increased appendicular lean mass and decreased trunk adipose mass and insulin resistance. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Bile acid composition of gallbladder contents in dogs with gallbladder mucocele and biliary sludge.

PubMed

Kakimoto, Toshiaki; Kanemoto, Hideyuki; Fukushima, Kenjiro; Ohno, Koichi; Tsujimoto, Hajime

2017-02-01

OBJECTIVE To examine bile acid composition of gallbladder contents in dogs with gallbladder mucocele and biliary sludge. ANIMALS 18 dogs with gallbladder mucocele (GBM group), 8 dogs with immobile biliary sludge (i-BS group), 17 dogs with mobile biliary sludge (m-BS group), and 14 healthy dogs (control group). PROCEDURES Samples of gallbladder contents were obtained by use of percutaneous ultrasound-guided cholecystocentesis or during cholecystectomy or necropsy. Concentrations of 15 bile acids were determined by use of highperformance liquid chromatography, and a bile acid compositional ratio was calculated for each group. RESULTS Concentrations of most bile acids in the GBM group were significantly lower than those in the control and m-BS groups. Compositional ratio of taurodeoxycholic acid, which is 1 of 3 major bile acids in dogs, was significantly lower in the GBM and i-BS groups, compared with ratios for the control and m-BS groups. The compositional ratio of taurocholic acid was significantly higher and that of taurochenodeoxycholic acid significantly lower in the i-BS group than in the control group. CONCLUSIONS AND CLINICAL RELEVANCE In this study, concentrations and fractions of bile acids in gallbladder contents were significantly different in dogs with gallbladder mucocele or immobile biliary sludge, compared with results for healthy control dogs. Studies are needed to determine whether changes in bile acid composition are primary or secondary events of gallbladder abnormalities.

Relative Amino Acid Composition Signatures of Organisms and Environments

PubMed Central

Moura, Alexandra; Savageau, Michael A.; Alves, Rui

2013-01-01

Background Identifying organism-environment interactions at the molecular level is crucial to understanding how organisms adapt to and change the chemical and molecular landscape of their habitats. In this work we investigated whether relative amino acid compositions could be used as a molecular signature of an environment and whether such a signature could also be observed at the level of the cellular amino acid composition of the microorganisms that inhabit that environment. Methodologies/Principal Findings To address these questions we collected and analyzed environmental amino acid determinations from the literature, and estimated from complete genomic sequences the global relative amino acid abundances of organisms that are cognate to the different types of environment. Environmental relative amino acid abundances clustered into broad groups (ocean waters, host-associated environments, grass land environments, sandy soils and sediments, and forest soils), indicating the presence of amino acid signatures specific for each environment. These signatures correlate to those found in organisms. Nevertheless, relative amino acid abundance of organisms was more influenced by GC content than habitat or phylogeny. Conclusions Our results suggest that relative amino acid composition can be used as a signature of an environment. In addition, we observed that the relative amino acid composition of organisms is not highly determined by environment, reinforcing previous studies that find GC content to be the major factor correlating to amino acid composition in living organisms. PMID:24204807

Relative amino acid composition signatures of organisms and environments.

PubMed

Moura, Alexandra; Savageau, Michael A; Alves, Rui

2013-01-01

Identifying organism-environment interactions at the molecular level is crucial to understanding how organisms adapt to and change the chemical and molecular landscape of their habitats. In this work we investigated whether relative amino acid compositions could be used as a molecular signature of an environment and whether such a signature could also be observed at the level of the cellular amino acid composition of the microorganisms that inhabit that environment. To address these questions we collected and analyzed environmental amino acid determinations from the literature, and estimated from complete genomic sequences the global relative amino acid abundances of organisms that are cognate to the different types of environment. Environmental relative amino acid abundances clustered into broad groups (ocean waters, host-associated environments, grass land environments, sandy soils and sediments, and forest soils), indicating the presence of amino acid signatures specific for each environment. These signatures correlate to those found in organisms. Nevertheless, relative amino acid abundance of organisms was more influenced by GC content than habitat or phylogeny. Our results suggest that relative amino acid composition can be used as a signature of an environment. In addition, we observed that the relative amino acid composition of organisms is not highly determined by environment, reinforcing previous studies that find GC content to be the major factor correlating to amino acid composition in living organisms.

Nitrogen additions affect litter quality and soil biochemical properties in a peatland of Northeast China

USGS Publications Warehouse

Song, Yanyu; Song, Changchun; Meng, Henan; Swarzenski, Christopher M.; Wang, Xianwei; Tan, Wenwen

2017-01-01

Nitrogen (N) is a limiting nutrient in many peatland ecosystems. Enhanced N deposition, a major component of global climate change, affects ecosystem carbon (C) balance and alters soil C storage by changing plant and soil properties. However, the effects of enhanced N deposition on peatland ecosystems are poorly understood. We conducted a two-year N additions field experiment in a peatland dominated by Eriophorum vaginatum in the Da Xing’an Mountains, Northeast China. Four levels of N treatments were applied: (1) CK (no N added), (2) N1 (6 g N m−2 yr−1), (3) N2 (12 g N m−2 yr−1), and (4) N3 (24 g N m−2  yr−1). Plant and soil material was harvested at the end of the second growing season. N additions increased litter N and phosphorus (P) content, as well as β-glucosidase, invertase, and acid-phosphatase activity, but decreased litter C:N and C:P ratios. Litter carbon content remained unchanged. N additions increased available NH4+–N and NO3−–N as well as total Gram-positive (Gram+), Gram-negative (Gram−), and total bacterial phospholipid fatty acids (PLFA) in shallow soil (0–15 cm depth). An increase in these PLFAs was accompanied by a decrease in soil labile organic C (microbial biomass carbon and dissolved organic carbon), and appeared to accelerate decomposition and reduce the stability of the soil C pool. Invertase and urease activity in shallow soils and acid-phosphatase activity in deep soils (15–30 cm depth) was inhibited by N additions. Together, these findings suggest that an increase in N deposition in peatlands could accelerate litter decomposition and the loss of labile C, as well as alter microbial biomass and function.

The Acid-Base Properties and Chemical Composition of the Surface of the InSb-ZnTe System

NASA Astrophysics Data System (ADS)

Kirovskaya, I. A.; Shubenkova, E. G.; Timoshenko, O. T.; Filatova, T. N.

2008-04-01

The acid-base properties and chemical composition of the surface of solid solutions and binary components of the InSb-ZnTe system were studied by the hydrolytic adsorption, nonaqueous conductometric titration, mechanochemistry, IR spectroscopy, and mass spectrometry methods. The strength, nature, and concentration of acid centers were determined. Changes in the concentration of acid centers caused by surface exposure to CO and changes in the composition of the system were also studied. The mechanism of acid-base interactions was established. The chemical composition of the surface of system components exposed to air included adsorbed H2O molecules, OH- groups, hydrocarbon and oxocarbon compounds, and the products of surface atom oxidation. After thermal treatment in a vacuum, the composition of the surface approached the stoichiometric composition.

Halogenated solvent remediation

DOEpatents

Sorenson, Kent S.

2004-08-31

Methods for enhancing bioremediation of ground water contaminated with nonaqueous halogenated solvents are disclosed. A preferred method includes adding a composition to the ground water wherein the composition is an electron donor for microbe-mediated reductive dehalogenation of the halogenated solvents and enhances mass transfer of the halogenated solvents from residual source areas into the aqueous phase of the ground water. Illustrative compositions effective in these methods include surfactants such as C.sub.2 -C.sub.4 carboxylic acids and hydroxy acids, salts thereof, esters of C.sub.2 -C.sub.4 carboxylic acids and hydroxy acids, and mixtures thereof. Especially preferred compositions for use in these methods include lactic acid, salts of lactic acid, such as sodium lactate, lactate esters, and mixtures thereof. The microbes are either indigenous to the ground water, or such microbes can be added to the ground water in addition to the composition.

Proximate composition and nutritional evaluation of the adductor muscle of pen shell.

PubMed

Wu, Shengjun; Wu, Yuping

2017-07-01

The proximate composition of pen shell adductor muscle (PSAM) was determined, and its nutrition value was evaluated. Proximate composition analysis indicated that PSAM contained 91.07% (w/w) protein, 5.77% (w/w) ash, and 2.46% (w/w) fat. Calcium was the predominant mineral followed by zinc and then iron. The amino acid profile was in accordance with the recommended pattern of FAO/WHO except for histidine. At the same time, the first limiting amino acid was histidine. Fatty acid composition showed that docosahexaenoic acid was the major fatty acid, followed by palmitic, stearic, and arachidonic acids. Results indicated that PSAM was rich in nutrition and may be developed as a functional food.

Effect of γ irradiation on the fatty acid composition of soybean and soybean oil.

PubMed

Minami, Ikuko; Nakamura, Yoshimasa; Todoriki, Setsuko; Murata, Yoshiyuki

2012-01-01

Food irradiation is a form of food processing to extend the shelf life and reduce spoilage of food. We examined the effects of γ radiation on the fatty acid composition, lipid peroxidation level, and antioxidative activity of soybean and soybean oil which both contain a large amount of unsaturated fatty acids. Irradiation at 10 to 80 kGy under aerobic conditions did not markedly change the fatty acid composition of soybean. While 10-kGy irradiation did not markedly affect the fatty acid composition of soybean oil under either aerobic or anaerobic conditions, 40-kGy irradiation considerably altered the fatty acid composition of soybean oil under aerobic conditions, but not under anaerobic conditions. Moreover, 40-kGy irradiation produced a significant amount of trans fatty acids under aerobic conditions, but not under anaerobic conditions. Irradiating soybean oil induced lipid peroxidation and reduced the radical scavenging activity under aerobic conditions, but had no effect under anaerobic conditions. These results indicate that the fatty acid composition of soybean was not markedly affected by radiation at 10 kGy, and that anaerobic conditions reduced the degradation of soybean oil that occurred with high doses of γ radiation.

Composition of plasma and atheromatous plaque among coronary artery disease subjects consuming coconut oil or sunflower oil as the cooking medium.

PubMed

Palazhy, Sabitha; Kamath, Prakash; Rajesh, P C; Vaidyanathan, Kannan; Nair, Shiv K; Vasudevan, D M

2012-12-01

Coconut oil, which is rich in medium-chain saturated fatty acids, is the principal cooking medium of the people of Kerala, India. Replacement of saturated fat with polyunsaturated fat is effective in reducing serum cholesterol levels. However, the effect of substituting coconut oil with sunflower oil on the fatty acid composition of plaque has not been thoroughly investigated. We therefore evaluated and compared the fatty acid composition of plasma and plaque among subjects consuming coconut oil or sunflower oil as the cooking medium. Endarterectomy samples and plasma samples were obtained from subjects who underwent coronary artery bypass grafts (n = 71). The subjects were grouped based on the type of oil they were using as their cooking medium (coconut oil or sunflower oil). The fatty acid composition in the plaques and the plasma was determined by HPLC and the data were analyzed statistically. Sunflower oil consumers had elevated concentrations of linoleic acid (p = 0.001) in plasma, while coconut oil users had higher myristic acid levels (p = 0.011) in plasma. Medium-chain fatty acids did not differ significantly between the two groups in the plasma. Medium-chain fatty acids were detected in the plaques in both groups of subjects. In contrast to previous reports, long-chain saturated fatty acids dominated the lipid content of plaque in this population, and the fatty acid composition of plaque was not significantly different between the two groups. No correlation between fatty acids of plasma and plaque was observed in either group. A change in cooking medium, although it altered the plasma fatty acid composition, was not reflected in the plaque composition.

Investigating the long-term legacy of drought and warming on the soil microbial community across five European shrubland ecosystems.

PubMed

Rousk, Johannes; Smith, Andrew R; Jones, Davey L

2013-12-01

We investigated how the legacy of warming and summer drought affected microbial communities in five different replicated long-term (>10 years) field experiments across Europe (EU-FP7 INCREASE infrastructure). To focus explicitly on legacy effects (i.e., indirect rather than direct effects of the environmental factors), we measured microbial variables under the same moisture and temperature in a brief screening, and following a pre-incubation at stable conditions. Specifically, we investigated the size and composition of the soil microbial community (PLFA) alongside measurements of bacterial (leucine incorporation) and fungal (acetate in ergosterol incorporation) growth rates, previously shown to be highly responsive to changes in environmental factors, and microbial respiration. We found no legacy effects on the microbial community size, composition, growth rates, or basal respiration rates at the effect sizes used in our experimental setup (0.6 °C, about 30% precipitation reduction). Our findings support previous reports from single short-term ecosystem studies thereby providing a clear evidence base to allow long-term, broad-scale generalizations to be made. The implication of our study is that warming and summer drought will not result in legacy effects on the microbial community and their processes within the effect sizes here studied. While legacy effects on microbial processes during perturbation cycles, such as drying-rewetting, and on tolerance to drought and warming remain to be studied, our results suggest that any effects on overall ecosystem processes will be rather limited. Thus, the legacies of warming and drought should not be prioritized factors to consider when modeling contemporary rates of biogeochemical processes in soil. © 2013 John Wiley & Sons Ltd.

Characteristic lipids of Bordetella pertussis: simple fatty acid composition, hydroxy fatty acids, and an ornithine-containing lipid.

PubMed Central

Kawai, Y; Moribayashi, A

1982-01-01

The lipids and fatty acids of Bordetella pertussis (phases I to IV) were analyzed by thin-layer chromatography, gas-liquid chromatography, and mass spectrometry and compared with those of B. parapertussis and B. bronchiseptica. The major lipid components of the three species were phosphatidylethanolamine, cardiolipin, phosphatidylglycerol, lysophosphatidylethanolamine, and an ornithine-containing lipid. The ornithine-containing lipid was characteristic of the genus Bordetella. The fatty acid composition of the total extractable cellular lipids of B. pertussis was mostly hexadecanoic and hexadecenoic acids (90%) in a ratio of about 1:1. The hexadecenoic acid of B. pertussis was in the cis-9 form. The fatty acid composition of the residual bound lipids was distinctly different from that of the extractable lipids, and residual bound lipids being mainly 3-hydroxytetradecanoic, tetradecanoic, and 3-hydroxydecanoic acids, with 3-hydroxydodecanoic acid occurring in some strains. It was determined that the 3-hydroxy fatty acids were derived from lipid A. The fatty acid composition of the total extractable cellular lipids of B. parapertussis and B. bronchiseptica, mainly composed of hexadecanoic and heptadecacyclopropanoic acid, differed from that of B. pertussis. Although the fatty acid composition of the residual bound lipids of B. parapertussis was similar to that of the residual bound lipids of B. pertussis, 2-hydroxydodecanoic acid was detected only in the bound lipids of B. bronchiseptica. Images PMID:6284719

Characteristic lipids of Bordetella pertussis: simple fatty acid composition, hydroxy fatty acids, and an ornithine-containing lipid.

PubMed

Kawai, Y; Moribayashi, A

1982-08-01

The lipids and fatty acids of Bordetella pertussis (phases I to IV) were analyzed by thin-layer chromatography, gas-liquid chromatography, and mass spectrometry and compared with those of B. parapertussis and B. bronchiseptica. The major lipid components of the three species were phosphatidylethanolamine, cardiolipin, phosphatidylglycerol, lysophosphatidylethanolamine, and an ornithine-containing lipid. The ornithine-containing lipid was characteristic of the genus Bordetella. The fatty acid composition of the total extractable cellular lipids of B. pertussis was mostly hexadecanoic and hexadecenoic acids (90%) in a ratio of about 1:1. The hexadecenoic acid of B. pertussis was in the cis-9 form. The fatty acid composition of the residual bound lipids was distinctly different from that of the extractable lipids, and residual bound lipids being mainly 3-hydroxytetradecanoic, tetradecanoic, and 3-hydroxydecanoic acids, with 3-hydroxydodecanoic acid occurring in some strains. It was determined that the 3-hydroxy fatty acids were derived from lipid A. The fatty acid composition of the total extractable cellular lipids of B. parapertussis and B. bronchiseptica, mainly composed of hexadecanoic and heptadecacyclopropanoic acid, differed from that of B. pertussis. Although the fatty acid composition of the residual bound lipids of B. parapertussis was similar to that of the residual bound lipids of B. pertussis, 2-hydroxydodecanoic acid was detected only in the bound lipids of B. bronchiseptica.

Amino acid composition and antioxidant capacity of Spanish honeys.

PubMed

Pérez, Rosa Ana; Iglesias, María Teresa; Pueyo, Encarnación; Gonzalez, Montserrat; de Lorenzo, Cristina

2007-01-24

The amino acid composition of 53 honey samples from Spain, consisting of 39 floral, 5 honeydew, and 9 blend honeys, has been determined. Physicochemical characteristics, polyphenolic content, amino acid composition, and estimation of the radical scavenging capacity against the stable free radical DPPH of the honey samples were analyzed. The resulting data have been statistically evaluated. The results showed that pH, acidity, net absorbance, electrical conductivity, and total polyphenolic contents of the honeys showed a strong correlation with the radical scavenging capacity. The correlation between the radical scavenging capacity of honey and amino acid contents was high with 18 of the 20 amino acids detected, with correlation values higher than those obtained for polyphenolic content. These results suggest that the amino acid composition of honey is an indicator of the sample's scavenging capacity.

Changes in phosphatidylcholine fatty acid composition are associated with altered skeletal muscle insulin responsiveness in normal man.

PubMed

Clore, J N; Harris, P A; Li, J; Azzam, A; Gill, R; Zuelzer, W; Rizzo, W B; Blackard, W G

2000-02-01

The fatty acid composition of skeletal muscle cell membrane phospholipids (PLs) is known to influence insulin responsiveness in man. We have recently shown that the fatty acid composition of phosphatidylcholine (PC), and not phosphatidylethanolamine (PE), from skeletal muscle membranes is of particular importance in this relationship. Efforts to alter the PL fatty acid composition in animal models have demonstrated induction of insulin resistance. However, it has been more difficult to determine if changes in insulin sensitivity are associated with changes in the skeletal muscle membrane fatty acid composition of PL in man. Using nicotinic acid (NA), an agent known to induce insulin resistance in man, 9 normal subjects were studied before and after treatment for 1 month. Skeletal muscle membrane fatty acid composition of PC and PE from biopsies of vastus lateralis was correlated with insulin responsiveness using a 3-step hyperinsulinemic-euglycemic clamp. Treatment with NA was associated with a 25% increase in the half-maximal insulin concentration ([ED50] 52.0 +/- 7.5 to 64.6 +/- 9.0 microU/mL, P < .05), consistent with decreased peripheral insulin sensitivity. Significant changes in the fatty acid composition of PC, but not PE, were also observed after NA administration. An increase in the percentage of 16:0 (21% +/- 0.3% to 21.7% +/- 0.4%, P < .05) and decreases in 18:0 (6.2% +/- 0.5% to 5.1% +/- 0.4%, P = .01), long-chain n-3 fatty acids (1.7% +/- 0.2% to 1.4% +/- 0.1%, P < .01), and total polyunsaturated fatty acids ([PUFAs] 8.7% +/- 0.8% to 8.0% +/- 0.8%, P < .05) are consistent with a decrease in fatty acid length and unsaturation in PC following NA administration. The change in ED50 was significantly correlated with the change in PUFAs (r = -.65, P < .05). These studies suggest that the induction of insulin resistance with NA is associated with changes in the fatty acid composition of PC in man.

Comparative fatty acid composition of four Sargassum species (Fucales, Phaeophyta)

NASA Astrophysics Data System (ADS)

Wu, Xiang-Chun; Lu, Bao-Ren; Tseng, C. K.

1995-12-01

Fatty acid composition of four Sargassum species from Qingdao and Shidao, Shandong Province was investigated. 16:0 (palmitic acid) was the major saturated fatty acid. C18 and C20 were the main polyunsaturated fatty acids (PUFAs). Arachidonic acid and eicosapentaenoic acid predominated among polyenoic acids in all the algal species examined, except for Sargassum sp. which had low concentration of eicosapentaenoic acid.

Amino acid composition of some Mexican foods.

PubMed

Morales de León, Josefina; Camacho, M Elena; Bourges, Héctor

2005-06-01

Knowledge of the amino acid composition of foods is essential to calculate their chemical score, which is used to predict protein quality of foods and diets. Though amino acid composition of many foods is reasonably well established, better knowledge is needed on native foods consumed in different regions and countries. This paper presents the amino acid composition of different presentations of raw and processed foods produced and consumed in Mexico. The amino acid composition was determined using Beckman amino acid analyzers (models 116 and 6300). Tryptophan was determined using the Spies and Chambers method. Of the different foods analyzed, some comments are made on native or basic foods in Mexico: Spirulin, where lysine is the limiting amino acid, with a chemical score of 67%, is a good source of tryptophan (1.16g/16 gN); amaranth contains high levels of sulphur amino acids (4.09 to 5.34 g/16gN), with a protein content of 15 g/100g; and pulque, a Pre-Hispanic beverage that contains high levels of tryptophan (2.58 g/16 gN) and sulphur amino acids (2.72 g/16 gN). Finally, insects are good sources of sulphur amino acids and lysine.

Seasonal patterns in stream periphyton fatty acids and community benthic algal composition in six high quality headwater streams

USGS Publications Warehouse

Honeyfield, Dale C.; Maloney, Kelly O.

2015-01-01

Fatty acids are integral components of periphyton and differ among algal taxa. We examined seasonal patterns in periphyton fatty acids in six minimally disturbed headwater streams in Pennsylvania’s Appalachian Mountains, USA. Environmental data and periphyton were collected across four seasons for fatty acid and algal taxa content. Non-metric multidimensional scaling ordination suggested significant seasonal differences in fatty acids; an ordination on algal composition revealed similar seasonal patterns, but with slightly weaker separation of summer and fall. Summer and fall fatty acid profiles were driven by temperature, overstory cover, and conductivity and winter profiles by measures of stream size. Ordination on algal composition suggested that summer and fall communities were driven by overstory and temperature, whereas winter communities were driven by velocity. The physiologically important fatty acid 18:3ω6 was highest in summer and fall. Winter samples had the highest 20:3ω3. Six saturated fatty acids differed among the seasons. Periphyton fatty acids profiles appeared to reflect benthic algal species composition. This suggests that periphyton fatty acid composition can be useful in characterizing basal food resources and stream water quality.

Seasonal biochemical changes in composition of body wall tissues of sea cucumber Apostichopus japonicus

NASA Astrophysics Data System (ADS)

Gao, Fei; Xu, Qiang; Yang, Hongsheng

2011-03-01

Seasonal Variation in proximate, amino acid and fatty acid composition of the body wall of sea cucumber Apostichopus japonicus was evaluated. The proximate composition, except for ash content, changed significantly among seasons ( P<0.05). Alanine, glycine, glutamic acid and asparagic acid were the most abundant amino acids. Total amino acid and essential amino acid Contents both varied clearly with seasons ( P<0.05). 16:0 and 16:ln7 were the primary saturated fatty acid (SFA) and monounsaturated fatty acid (MUFA) respectively for all months. EPA (20:5n-3), AA (20:4n-6) and DHA (22:6n-3) were the major polyunsaturated fatty acids (PUFA). The proportions of SFA and PUFA yielded significant seasonal variations ( P<0.001), but MUFA did not changed significantly. The results indicated that the biochemical compositions of the body wall in A. japonicus were significantly influenced by seasons and that the body wall tissue is an excellent source of protein, MUFA and n-3 PUFA for humans.

Sulfonated mesoporous silica-carbon composites and their use as solid acid catalysts

NASA Astrophysics Data System (ADS)

Valle-Vigón, Patricia; Sevilla, Marta; Fuertes, Antonio B.

2012-11-01

The synthesis of highly functionalized porous silica-carbon composites made up of sulfonic groups attached to a carbon layer coating the pores of three types of mesostructured silica (i.e. SBA-15, KIT-6 and mesocellular silica) is presented. The synthesis procedure involves the following steps: (a) removal of the surfactant, (b) impregnation of the silica pores with a carbon precursor, (c) carbonization and (d) sulfonation. The resulting silica-carbon composites contain ˜30 wt % of carbonaceous matter with a high density of acidic groups attached to the deposited carbon (i.e.sbnd SO3H, sbnd COOH and sbnd OH). The structural characteristics of the parent silica are retained in the composite materials, which exhibit a high surface area, a large pore volume and a well-ordered porosity made up uniform mesopores. The high density of the sulfonic groups in combination with the mesoporous structure of the composites ensures that a large number of active sites are easily accessible to reactants. These sulfonated silica-carbon composites behave as eco-friendly, active, selective, water tolerant and recyclable solid acids. In this study we demonstrate the usefulness of these composites as solid acid catalysts for the esterification of maleic anhydride, succinic acid and oleic acid with ethanol. These composites exhibit a superior intrinsic catalytic activity to other commercial solid acids such as Amberlyst-15.

Acid Response of Bifidobacterium longum subsp. longum BBMN68 Is Accompanied by Modification of the Cell Membrane Fatty Acid Composition.

PubMed

Liu, Songling; Ren, Fazheng; Jiang, Jingli; Zhao, Liang

2016-07-28

The acid response of Bifidobacterium longum subsp. longum BBMN68 has been studied in our previous study. The fab gene, which is supposed to be involved in membrane fatty acid biosynthesis, was demonstrated to be induced in acid response. In order to investigate the relationship between acid response and cell membrane fatty acid composition, the acid adaptation of BBMN68 was assessed and the membrane fatty acid composition at different adaptation conditions was identified. Indeed, the fatty acid composition was influenced by acid adaptation. Our results showed that the effective acid adaptations were accompanied with decrease in the unsaturated to saturated fatty acids ratio (UFA/SFA) and increase in cyclopropane fatty acid (CFA) content, which corresponded to previous studies. Moreover, both effective and non-effective acid adaptation conditions resulted in decrease in the C18:1 cis-9/C18:1 trans-9 ratio, indicating that the C18:1 cis-9/C18:1 trans-9 ratio is associated with acid tolerance response but not with acid adaptation response. Taken together, this study indicated that the UFA/SFA and CFA content of BBMN68 were involved in acid adaptation and the C18:1 cis-9/C18:1 trans-9 ratio was involved in acid tolerance response.

Method of making alkyl esters

DOEpatents

Elliott, Brian

2010-09-14

Methods of making alkyl esters are described herein. The methods are capable of using raw, unprocessed, low-cost feedstocks and waste grease. Generally, the method involves converting a glyceride source to a fatty acid composition and esterifying the fatty acid composition to make alkyl esters. In an embodiment, a method of making alkyl esters comprises providing a glyceride source. The method further comprises converting the glyceride source to a fatty acid composition comprising free fatty acids and less than about 1% glyceride by mass. Moreover, the method comprises esterifying the fatty acid composition in the presence of a solid acid catalyst at a temperature ranging firm about 70.degree. C. to about 120.degree. C. to produce alkyl esters, such that at least 85% of the free fatty acids are converted to alkyl esters. The method also incorporates the use of packed bed reactors for glyceride conversion and/or fatty acid esterification to make alkyl esters.

Surface treated carbon catalysts produced from waste tires for fatty acids to biofuel conversion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hood, Zachary D.; Adhikari, Shiba P.; Wright, Marcus W.

A method of making solid acid catalysts includes the step of sulfonating waste tire pieces in a first sulfonation step. The sulfonated waste tire pieces are pyrolyzed to produce carbon composite pieces having a pore size less than 10 nm. The carbon composite pieces are then ground to produce carbon composite powders having a size less than 50 .mu.m. The carbon composite particles are sulfonated in a second sulfonation step to produce sulfonated solid acid catalysts. A method of making biofuels and solid acid catalysts are also disclosed.

Isolation and Characterization of Bacteria from Ancient Siberian Permafrost Sediment

PubMed Central

Zhang, De-Chao; Brouchkov, Anatoli; Griva, Gennady; Schinner, Franz; Margesin, Rosa

2013-01-01

In this study, we isolated and characterized bacterial strains from ancient (Neogene) permafrost sediment that was permanently frozen for 3.5 million years. The sampling site was located at Mammoth Mountain in the Aldan river valley in Central Yakutia in Eastern Siberia. Analysis of phospolipid fatty acids (PLFA) demonstrated the dominance of bacteria over fungi; the analysis of fatty acids specific for Gram-positive and Gram-negative bacteria revealed an approximately twofold higher amount of Gram-negative bacteria compared to Gram-positive bacteria. Direct microbial counts after natural permafrost enrichment showed the presence of (4.7 ± 1.5) × 108 cells g−1 sediment dry mass. Viable heterotrophic bacteria were found at 0 °C, 10 °C and 25 °C, but not at 37 °C. Spore-forming bacteria were not detected. Numbers of viable fungi were low and were only detected at 0 °C and 10 °C. Selected culturable bacterial isolates were identified as representatives of Arthrobacter phenanthrenivorans, Subtercola frigoramans and Glaciimonas immobilis. Representatives of each of these species were characterized with regard to their growth temperature range, their ability to grow on different media, to produce enzymes, to grow in the presence of NaCl, antibiotics, and heavy metals, and to degrade hydrocarbons. All strains could grow at −5 °C; the upper temperature limit for growth in liquid culture was 25 °C or 30 °C. Sensitivity to rich media, antibiotics, heavy metals, and salt increased when temperature decreased (20 °C > 10 °C > 1 °C). In spite of the ligninolytic activity of some strains, no biodegradation activity was detected. PMID:24832653

Phospholipid Evidence for Methanogenic Archaea and Sulfate-reducing Bacteria in Coalbed Methane Wells in the Powder River Basin, Wyoming

NASA Astrophysics Data System (ADS)

Glossner, A.; Flores, R. M.; Mandernack, K.

2008-12-01

The Powder River Basin (PRB) comprises roughly 22,000 mi2 in northeastern Wyoming and southeastern Montana; it is a major source of coal and natural gas in the Rocky Mountain and Great Plains regions. The coalbed methane (CBM) produced from Paleocene Fort Union Formation coals in the PRB is thought primarily to be of bacterial origin due to its low δ13C values of -51 to -82 permil. Determination of the timing of methanogenesis, however, requires a methodology suitable for distinguishing viable methanogenic microorganisms. Here we provide evidence of living methanogenic Archaea and sulfate- reducing bacteria collected from co-produced water from CBM wells using phospholipid fatty acid (PLFA) and phospholipid ether lipid (PLEL) analyses. Twelve producing wells were sampled in May, 2007, using a high- pressure filtering apparatus. PLFAs were analyzed as fatty acid methyl esters and PLELs analyzed by their liberated core components using gas chromatography/mass spectrometry. Phospholipid analyses revealed an ecosystem dominated by Archaea, as the Archaeal isoprenoid, phytane, was the dominant phospholipid observed in nine of the wells sampled. Total microbial biomass estimates ranged from 1.1 ×106 cells/L to 8.3 ×107 cells/L, with the proportion of Archaeal cells ranging from 77.5 to 99.7 percent. In addition, the biomarkers 10me16:0, and cy17:0, considered to be biomarkers for genera of sulfate-reducing bacteria, were observed in several wells. The dominance of lipids from living Archaea in co- produced waters from CBM wells provides evidence supporting a recent origin of gas in the PRB coals.

A simple evaluation of soil quality of waterlogged purple paddy soils with different productivities.

PubMed

Liu, Zhanjun; Zhou, Wei; Lv, Jialong; He, Ping; Liang, Guoqing; Jin, Hui

2015-01-01

Evaluation of soil quality can be crucial for designing efficient farming systems and ensuring sustainable agriculture. The present study aimed at evaluating the quality of waterlogged purple paddy soils with different productivities in Sichuan Basin. The approach involved comprehensive analyses of soil physical and chemical properties, as well as enzyme activities and microbial community structure measured by phospholipid fatty acid analysis (PLFA). A total of 36 soil samples were collected from four typical locations, with 12 samples representing high productivity purple paddy soil (HPPS), medium productivity purple paddy soil (MPPS) and low productivity purple paddy soil (LPPS), respectively. Most measured soil properties showed significant differences (P ≤ 0.05) among HPPS, MPPS and LPPS. Pearson correlation analysis and principal component analysis were used to identify appropriate soil quality indicators. A minimum data set (MDS) including total nitrogen (TN), available phosphorus (AP), acid phosphatase (ACP), total bacteria (TB) and arbuscular mycorrhizal fungi was established and accounted for 82.1% of the quality variation among soils. A soil quality index (SQI) was developed based on the MDS method, whilst HPPS, MPPS and LPPS received mean SQI scores of 0.725, 0.536 and 0.425, respectively, with a ranking of HPPS > MPPS > LPPS. HPPS showed relatively good soil quality characterized by optimal nutrient availability, enzymatic and microbial activities, but the opposite was true of LPPS. Low levels of TN, AP and soil microbial activities were considered to be the major constraints limiting the productivity in LPPS. All soil samples collected were rich in available N, K, Si and Zn, but deficient in available P, which may be the major constraint for the studied regions. Managers in our study area should employ more appropriate management in the LPPS to improve its rice productivity, and particularly to any potential limiting factor.

Thermal and Mechanical Characteristics of Polymer Composites Based on Epoxy Resin, Aluminium Nanopowders and Boric Acid

NASA Astrophysics Data System (ADS)

Nazarenko, O. B.; Melnikova, T. V.; Visakh, P. M.

2016-01-01

The epoxy polymers are characterized by low thermal stability and high flammability. Nanoparticles are considered to be effective fillers of polymer composites for improving their thermal and functional properties. In this work, the epoxy composites were prepared using epoxy resin ED-20, polyethylene polyamine as a hardener, aluminum nanopowder and boric acid fine powder as flame-retardant filler. The thermal characteristics of the obtained samples were studied using thermogravimetric analysis and differential scanning calorimetry. The mechanical characteristics of epoxy composites were also studied. It was found that an addition of all fillers enhances the thermal stability and mechanical characteristics of the epoxy composites. The best thermal stability showed the epoxy composite filled with boric acid. The highest flexural properties showed the epoxy composite based on the combination of boric acid and aluminum nanopowder.

Milk fat globules: fatty acid composition, size and in vivo regulation of fat liquidity.

PubMed

Timmen, H; Patton, S

1988-07-01

Populations of large and small milk fat globules were isolated and analyzed to determine differences in fatty acid composition. Globule samples were obtained by centrifugation from milks of a herd and of individual animals produced under both pasture and barn feeding. Triacylglycerols of total globule lipids were prepared by thin layer chromatography and analyzed for fatty acid composition by gas chromatography. Using content of the acids in large globules as 100%, small globules contained fewer short-chain acids, -5.9%, less stearic acid, -22.7%, and more oleic acids, +4.6%, mean values for five trials. These differences are consistent with alternative use of short-chain acids or oleic acid converted from stearic acid to maintain liquidity at body temperature of milk fat globules and their precursors, intracellular lipid droplets. Stearyl-CoA desaturase (EC 1.14.99.5), which maintains fluidity of cellular endoplasmic reticulum membrane, is suggested to play a key role in regulating globule fat liquidity. Possible origins of differences between individual globules in fatty acid composition of their triacylglycerols are discussed.

Use of super acids to digest chrysotile and amosite asbestos in simple mixtures or matrices found in building materials compositions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sugama, T.; Petrakis, L.; Webster, R.P.

A composition for converting asbestos-containing material to environmentally benign components is provided. The composition comprises a fluoro acid decomposing agent which can be applied to either amosite-containing thermal insulation or chrysotile-containing fire-proof material or to any asbestos-containing material which includes of chrysotile and amosite asbestos. The fluoro acid decomposing agent includes FP{sub 0}(OH){sub 2}, hexafluorophosphoric acid, a mixture of hydrofluoric and phosphoric acid and a mixture of hexafluorophosphoric acid and phosphoric acid. A method for converting asbestos-containing material to environmentally benign components is also provided.

Advances in food composition tables in Japan-Standard Tables Of Food Composition in Japan - 2015 - (Seventh Revised Edition).

PubMed

Watanabe, Tomoko; Kawai, Ryoko

2018-01-01

The latest version of the Standard Tables of Food Composition in Japan-2015- comprises the main food composition table (Standard Tables of Food Composition in Japan-2015-[Seventh revised Edition)) and three supplementary books. The supplementary books are Standard Tables of Food Composition in Japan - 2015 - (Seventh Revised Edition) - Amino Acids -, Standard Tables of Food Composition in Japan - 2015 - (Seventh Revised Edition) - Fatty Acids - and Standard Tables of Food Composition in Japan - 2015 - (Seventh Revised Edition) - Available Carbohydrates, Polyols and Organic Acids-. We believe understanding these food composition tables can give greater insight into Japan's gastronomic culture and changes in eating habits. We expect them to play important roles as part of the East Asia food composition tables. Copyright © 2017. Published by Elsevier Ltd.

Shifts in soil chemical properties and bacterial communities responding to biotransformed dry olive residue used as organic amendment.

PubMed

Siles, José A; Cajthaml, Tomas; Hernández, Paola; Pérez-Mendoza, Daniel; García-Romera, Inmaculada; Sampedro, Inmaculada

2015-07-01

Dry olive residue (DOR) is a waste product derived from olive oil extraction and has been proposed as an organic amendment. However, it has been demonstrated that a pre-treatment, such as its transformation by saprophytic fungi, is required before DOR soil application. A greenhouse experiment was designed where 0 and 50 g kg(-1) of raw DOR (DOR), Coriolopsis floccosa-transformed DOR (CORDOR) and Fusarium oxysporum-transformed DOR (FUSDOR) were added to soil. Analyses of the soil chemical properties as well as the structure and relative abundance of bacterial and actinobacterial communities were conducted after 0, 30 and 60 days following amendment. The different amendments produced a slight decrease in soil pH and significant increases in carbon fractions, C/N ratios, phenols and K, with these increases being more significant after DOR application. Quantitative PCR assays of the 16S rRNA gene and PLFA analyses showed that all amendments favoured bacterial growth at 30 and 60 days, although actinobacterial proliferation was more evident after CORDOR and FUSDOR application at 60 days. Bacterial and actinobacterial DGGE multivariate analyses showed that the amendments produced structural changes in both communities, especially after 60 days of amendment. PLFA data analysis identified changes in soil microbial communities according to the amendment considered, with FUSDOR and CORDOR being less disruptive than DOR. Finally, integrated analysis of all data monitored in the present study enabled us to conclude that the greatest impact on soil properties was caused by DOR at 30 days and that soil showed some degree of resilience after this time.

Hydrofluoric acid-resistant composite window and method for its fabrication

DOEpatents

Ostenak, C.A.; Mackay, H.A.

1985-07-18

A hydrofluoric acid-resistant composite window and method for its fabrication are disclosed. The composite window comprises a window having first and second sides. The first side is oriented towards an environment containing hydrofluoric acid. An adhesive is applied to the first side. A layer of transparent hydrofluoric acid-resistant material, such as Mylar, is applied to the adhesive and completely covers the first side. The adhesive is then cured.

Hydrofluoric acid-resistant composite window and method for its fabrication

DOEpatents

Ostenak, Carl A.; Mackay, Harold A.

1987-01-01

A hydrofluoric acid-resistant composite window and method for its fabrication are disclosed. The composite window comprises a window having first and second sides. The first side is oriented towards an environment containing hydrofluoric acid. An adhesive is applied to the first side. A layer of transparent hydrofluoric acid-resistant material, such as Mylar, is applied to the adhesive and completely covers the first side. The adhesive is then cured.

Effect of Gallic acid on mechanical and water barrier properties of zein-oleic acid composite films.

PubMed

Masamba, Kingsley; Li, Yue; Hategekimana, Joseph; Liu, Fei; Ma, Jianguo; Zhong, Fang

2016-05-01

In this study, the effect of gallic acid on mechanical and water barrier properties of zein-oleic acid 0-4 % composite films was investigated. Molecular weight distribution analysis was carried out to confirm gallic acid induced cross linking through change in molecular weight in fraction containing zein proteins. Results revealed that gallic acid treatment increased tensile strength from 17.9 MPa to 26.0 MPa, decreased water vapour permeability from 0.60 (g mm m(-2) h(-1) kPa(-1)) to 0.41 (g mm m(-2) h(-1) kPa(-1)), increased solubility from 6.3 % to 10.2 % and marginally increased elongation at break from 3.7 % to 4.2 % in zein films only. However, gallic acid treatment in zein-oleic composite films did not significantly influence mechanical and water barrier properties and in most instances irrespective of oleic acid concentration, the properties were negatively affected. Results from scanning electron microscopy showed that both gallic acid treated and untreated zein films and composite films containing 3 % oleic acid had a compact and homogeneous structure while those containing 4 % oleic acid had inhomogeneous structure. The findings have demonstrated that gallic acid treatment can significantly improve mechanical and water barrier properties especially in zein films only as opposed to when used in composite films using zein and oleic acid.

Single step synthesis of gold-amino acid composite, with the evidence of the catalytic hydrogen atom transfer (HAT) reaction, for the electrochemical recognition of Serotonin

NASA Astrophysics Data System (ADS)

Choudhary, Meenakshi; Siwal, Samarjeet; Nandi, Debkumar; Mallick, Kaushik

2016-03-01

A composite architecture of amino acid and gold nanoparticles has been synthesized using a generic route of 'in-situ polymerization and composite formation (IPCF)' [1,2]. The formation mechanism of the composite has been supported by a model hydrogen atom (H•≡H++e-) transfer (HAT) type of reaction which belongs to the proton coupled electron transfer (PCET) mechanism. The 'gold-amino acid composite' was used as a catalyst for the electrochemical recognition of Serotonin.

Intraspecies cellular fatty acids heterogeneity of Lactobacillus plantarum strains isolated from fermented foods in Ukraine.

PubMed

Garmasheva, I; Vasyliuk, O; Kovalenko, N; Ostapchuk, A; Oleschenko, L

2015-09-01

The intraspecies heterogeneity of cellular fatty acids composition of Lactobacillus plantarum strains isolated from Ukrainian traditional fermented foods was examined. Seven cellular fatty acids were identified. All Lact. plantarum strains investigated contained C16:0 (from 7·54 to 49·83% of total fatty acids), cC18:1 (3·23-38·67% of total fatty acids) and cycC19:0 acids (9·03-67·68% of total fatty acids) as the major fatty acids. The tC18:1 acid made up 1·47-22·0% of the total fatty acids. The C14:0 and C16:1 acids were present in small amounts (0·22-6·96% and 0·66-7·42% respectively) in most Lact. plantarum strains. Differences in relative contents of some fatty acids between Lact. plantarum strains depending on the source isolation were found. Isolates of dairy origin contained slightly greater levels of the C16:0 and tC18:1 fatty acids and lower levels of the cC18:1 than strains obtained from fermented vegetables. The origin of Lact. plantarum strains affects their fatty acids composition, which in turn, appears to be related to their ability to growth under stress factors. Cellular fatty acids composition is an important chemotaxonomic characteristic of bacterial cells. At the same time cellular fatty acids play a key role in maintaining the viability of micro-organisms in different environmental conditions. In this study, intraspecies heterogeneity of cellular fatty acids composition of Lactobacillus plantarum strains was examined. This work provides novel and important information about a relationship between cellular fatty acids composition of Lact. plantarum strains and source of isolation or stress resistance profile. Our results showed that cellular fatty acids composition is quite diverse among Lact. plantarum strains derived from different sources and may reflect previous cell's history. Our findings should be considered in chemotaxonomic studies of lactic acid bacteria and its ecology. © 2015 The Society for Applied Microbiology.

A simple 2D composite image analysis technique for the crystal growth study of L-ascorbic acid.

PubMed

Kumar, Krishan; Kumar, Virender; Lal, Jatin; Kaur, Harmeet; Singh, Jasbir

2017-06-01

This work was destined for 2D crystal growth studies of L-ascorbic acid using the composite image analysis technique. Growth experiments on the L-ascorbic acid crystals were carried out by standard (optical) microscopy, laser diffraction analysis, and composite image analysis. For image analysis, the growth of L-ascorbic acid crystals was captured as digital 2D RGB images, which were then processed to composite images. After processing, the crystal boundaries emerged as white lines against the black (cancelled) background. The crystal boundaries were well differentiated by peaks in the intensity graphs generated for the composite images. The lengths of crystal boundaries measured from the intensity graphs of composite images were in good agreement (correlation coefficient "r" = 0.99) with the lengths measured by standard microscopy. On the contrary, the lengths measured by laser diffraction were poorly correlated with both techniques. Therefore, the composite image analysis can replace the standard microscopy technique for the crystal growth studies of L-ascorbic acid. © 2017 Wiley Periodicals, Inc.

Amino acid composition in determination of collagen origin and assessment of physical factors effects.

PubMed

Gauza-Włodarczyk, Marlena; Kubisz, Leszek; Włodarczyk, Dariusz

2017-11-01

The amino acid composition of collagen is a characteristic feature of this protein. Collagen, irrespective of its origin, contains 19 amino acids, including hydroxyproline which does not occur in other proteins. Its atypical amino acid composition is characterized by high content of proline and glycine, as well as the absence of cysteine. This paper shows the comparison of qualitative composition of amino acids of fish skin (FS) collagen, bovine Achilles tendon (BAT) collagen, and bone collagen. Results demonstrate that FS collagen as well as BAT collagen contains no cysteine and significantly different amount of hydroxyproline. In BAT collagen hydroxyproline content is 30% higher than hydroxyproline content of FS collagen. In bone collagen the amount of hydroxyproline is two times more than in FS collagen. Furthermore, it is shown that sensitivity to radiation of individual amino acids varies and depends on the absorbed dose of ionizing radiation. The changes observed in the amino acid composition become very intense for the doses of 500kGy and 1000kGy. Copyright © 2017 Elsevier B.V. All rights reserved.

Effects of dietary omega-3 and -6 supplementations on phospholipid fatty acid composition in mice uterus during window of pre-implantation.

PubMed

Fattahi, Amir; Darabi, Masoud; Farzadi, Laya; Salmassi, Ali; Latifi, Zeinab; Mehdizadeh, Amir; Shaaker, Maghsood; Ghasemnejad, Tohid; Roshangar, Leila; Nouri, Mohammad

2018-03-01

Since fatty acid composition of uterus phospholipids is likely to influence embryo implantation, this study was conducted to investigate the effects of dietary omega-3 and -6 fatty acids on implantation rate as well as uterine phospholipid fatty acids composition during mice pre-implantation period. Sixty female mice were randomly distributed into:1) control (standard pellet), 2) omega-3 (standard pellet + 10% w/w of omega-3 fatty acids) and 3) omega-6 (standard pellet + 10% w/w of omega-6 fatty acids). Uterine phospholipid fatty acid composition during the pre-implantation window (days 1-5 of pregnancy) was analyzed using gas-chromatography. The implantation rate on the fifth day of pregnancy was also determined. Our results showed that on days 1, 2 and 3 of pregnancy, the levels of arachidonic acid (ARA) as well as total omega-6 fatty acids were significantly higher and the levels of linolenic acid and total omega-3 fatty acids were statistically lower in the omega-6 group compared to the omega-3 group (p < 0.05). On the fourth day of pregnancy, only the ARA, total omega-6 fatty acids, and poly-unsaturated fatty acids levels were significantly different between the two dietary supplemented groups (p < 0.05). There were positive correlations between the levels of omega-6 fatty acids, especially ARA, with the implantation rate. The present study showed that diets rich in omega-3 and -6 fatty acids could differently modify uterine phospholipid fatty acid composition and uterine levels of phospholipid ARA, and that the total omega-6 fatty acids had a positive association with the implantation rate. Copyright © 2017 Elsevier Inc. All rights reserved.

Metal etching composition

NASA Technical Reports Server (NTRS)

Otousa, Joseph E. (Inventor); Thomas, Clark S. (Inventor); Foster, Robert E. (Inventor)

1991-01-01

The present invention is directed to a chemical etching composition for etching metals or metallic alloys. The composition includes a solution of hydrochloric acid, phosphoric acid, ethylene glycol, and an oxidizing agent. The etching composition is particularly useful for etching metal surfaces in preparation for subsequent fluorescent penetrant inspection.

The relative proportions of different lipid classes and their fatty acid compositions change with culture age in the cariogenic dental pathogen Streptococcus mutans UA159.

PubMed

Custer, Jenny E; Goddard, Bryan D; Matter, Stephen F; Kaneshiro, Edna S

2014-06-01

The oral cariogenic bacterial pathogen Streptococcus mutans strain UA159 has become an important research organism strain since its genome was sequenced. However, there is a paucity of information on its lipidome using direct analytical biochemical approaches. We here report on comprehensive analyses of the major lipid classes and their fatty acids in cells grown in batch standing cultures. Using 2-D high-performance thin-layer chromatography lipid class composition changes were detected with culture age. More lipid components were detected in the stationary-phase compared to log-phase cells. The major lipids identified included 1,3-bis(sn-3'-phosphatidyl)-sn-glycerol (phosphatidylglycerol), 1,3-diphosphatidylglycerol (cardiolipin), aminoacyl-phosphatidylglycerol, monoglucosyldiacylglycerol, diglucosyldiacylglycerol, diglucosylmonoacylglycerol and, glycerophosphoryldiglucosyldiacylglycerol. Culture age also affected the fatty acid composition of the total polar lipid fraction. Thus, the major lipid classes detected in log-phase and stationary-phase cells were isolated and their fatty acids were analyzed by gas-liquid chromatography to determine the basis for the fatty acid compositional changes in the total polar lipid fraction. The analyses showed that the relative proportions of these acids changed with culture age within individual lipid classes. Hence fatty acid changes in the total polar lipid fraction reflected changes in both lipid class composition and fatty acid compositions within individual lipid classes.

Impact of Environment on the Biomass Composition of Soybean (Glycine max) seeds.

PubMed

McClure, Tamara; Cocuron, Jean-Christophe; Osmark, Veronika; McHale, Leah K; Alonso, Ana Paula

2017-08-16

Factors including genetics, fertilization, and climatic conditions, can alter the biomass composition of soybean seeds, consequently impacting their market value and usage. This study specifically determined the content of protein and oil, as well as the composition of proteinogenic amino acids and fatty acids in seeds from 10 diverse soybean cultivars grown in four different sites. The results highlighted that different environments produce a different composition for the 10 cultivars under investigation. Specifically, the levels of oleic and linoleic acids, important contributors to oil stability, were negatively correlated. Although the protein and oil contents were higher in some locations, their "quality" was lower in terms of composition of essential amino acids and oleic acid, respectively. Finally, proteinogenic histidine and glutamate were the main contributors to the separation between Central and Northern growing sites. Taken together, these results can guide future breeding and engineering efforts aiming to develop specialized soybean lines.

Use Of Superacids To Digest Chrysotile And Amosite Asbestos In Simple Mixtures Or Matrices Found In Building Materials Compositions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sugama, Toshifumi; Petrakis, Leon; Webster, Ronald P.

A composition for converting asbestos-containing material to environmentally benign components is provided. The composition comprises a flouro acid decomposing agent which can be applied to either amosite-containing thermal insulation or chrysotile-containing fire-proof material or to any asbestos-containing material which includes of chrysotile and amosite asbestos. The fluoro acid decomposing agent includes FP(O)(OH).sub.2, hexafluorophosphoric acid, a mixture of hydrofluoric and phosphoric acid and a mixture of hexafluorophosphoric acid and phosphoric acid. A method for converting asbestos-containing material to environmentally benign components is also provided

The influence of maternal ethnic group and diet on breast milk fatty acid composition.

PubMed

Su, Lin Lin; S K, Thamarai Chelvi; Lim, Su Lin; Chen, Yuming; Tan, Elizabeth A T; Pai, Namratha Narayan; Gong, Yin Han; Foo, Janie; Rauff, Mary; Chong, Yap Seng

2010-09-01

Breast milk fatty acids play a major role in infant development. However, no data have compared the breast milk composition of different ethnic groups living in the same environment. We aimed to (i) investigate breast milk fatty acid composition of three ethnic groups in Singapore and (ii) determine dietary fatty acid patterns in these groups and any association with breast milk fatty acid composition. This was a prospective study conducted at a tertiary hospital in Singapore. Healthy pregnant women with the intention to breastfeed were recruited. Diet profile was studied using a standard validated 3-day food diary. Breast milk was collected from mothers at 1 to 2 weeks and 6 to 8 weeks postnatally. Agilent gas chromatograph (6870N) equipped with a mass spectrometer (5975) and an automatic liquid sampler (ALS) system with a split mode was used for analysis. Seventy-two breast milk samples were obtained from 52 subjects. Analysis showed that breast milk ETA (Eicosatetraenoic acid) and ETA:EA (Eicosatrienoic acid) ratio were significantly different among the races (P = 0.031 and P = 0.020), with ETA being the highest among Indians and the lowest among Malays. Docosahexaenoic acid was significantly higher among Chinese compared to Indians and Malays. No difference was demonstrated in n3 and n6 levels in the food diet analysis among the 3 ethnic groups. Differences exist in breast milk fatty acid composition in different ethnic groups in the same region, although no difference was demonstrated in the diet analysis. Factors other than maternal diet may play a role in breast milk fatty acid composition.

Distribution and enantiomeric composition of amino acids in the Murchison meteorite

NASA Technical Reports Server (NTRS)

Engel, M. H.; Nagy, B.

1982-01-01

Studies of the amino acid contents and enantiomeric compositions of a single stone from the Murchison meteorite are reported. Water-extracted and 6M HCl-extracted samples from the meteorite interior of meteorite fragments were analyzed by gas chromatography and combined gas chromatography-chemical ionization mass spectrometry. Examination of the D/L ratios of glutamic acid, aspartic acid, proline, leucine and alanine reveals those amino acids extractable by water to be partially racemized, whereas the acid-extracted amino acids were less racemized. The amino acid composition of the stone is similar to those previously reported, including the absence of serine, threonine, tyrosine phenylalanine and methionine and the presence of unusual amino acids including such as isovaline, alpha-aminoisobutyric acid and pseudoleucine. It is concluded that the most likely mechanism accounting for the occurrence of nonracemic amino acid mixtures in the Murchison meteorite is by extraterrestrial stereoselective synthesis or decomposition reactions.

Changes in fats and resins of Pinus radiata associated with heartwood formation

Treesearch

Richard W. Hemingway; W.E. Hillis

1971-01-01

In an analysis of Australian grown P. radiata marked changes were found in the relative proportions and compositions of the resin acids, fatty acids, and fatty acid esters associated with heartwood formation. While the proportion of resin acids increased substantially in the heartwood, there was little change in resin acid composition from outer...

Superhard Transparent Coatings

DTIC Science & Technology

1975-04-01

alcohol has OH groups and polymethacrylic acid has carboxyl COOH groups. These form a clear suspension with the sub- micron hydrophilic particles...PHOSPHORIC ACID /SILICA/PVA 38 SYSTEM 3: ALON/POLYSILICIC ACID /BORACIC ACID 38 SYSTEM 4: ALON/SILICA/CYMEL - MOH HARDNESS VS...60 POLYSILICIC ACID 60 Methods for the Preparation of a Polystllcate/ Alon Suspension 61 Compositions 62 STRETCHED PLEX 63 OPTIMUM COMPOSITIONS

Comparison of Human Milk Fatty Acid Composition of Women From Cambodia and Australia.

PubMed

Gao, Chang; Liu, Ge; Whitfield, Kyly C; Kroeun, Hou; Green, Timothy J; Gibson, Robert A; Makrides, Maria; Zhou, Shao J

2018-05-01

Human milk is a rich source of omega-3 long-chain polyunsaturated fatty acids, which are postulated to be important for brain development. There is a lack of data on the human milk fatty acid composition of Cambodian women compared with data from Western women. Research Aim: The aim of this study was to determine the human milk fatty acid composition of women living in Cambodia and compare it with that of women living in Australia. Human milk samples from Cambodian ( n = 67) and Australian ( n = 200) mothers were collected at 3 to 4 months postpartum. Fatty acid composition was analyzed using capillary gas chromatography followed by Folch extraction with chloroform/methanol (2:1 v/v), and fat content was measured gravimetrically. Compared with Australian participants, human milk from Cambodian participants contained a significantly lower level of total fat (2.90 vs. 3.45 g/dL, p = .028), lower percentages of linoleic acid (9.30% vs. 10.66%, p < .0001) and α-linolenic acid (0.42% vs. 0.95%, p < .0001), but higher percentages of arachidonic acid (0.68% vs. 0.38%, p < .0001) and docosahexaenoic acid (0.40% vs. 0.23%, p < .0001). Differences in human milk fatty acid composition between Cambodian and Australian participants may be explained by differences in the dietary patterns between the two populations.

Fatty acid composition of Swedish bakery products, with emphasis on trans-fatty acids.

PubMed

Trattner, Sofia; Becker, Wulf; Wretling, Sören; Öhrvik, Veronica; Mattisson, Irene

2015-05-15

Trans-fatty acids (TFA) have been associated with increased risk of coronary heart disease, by affecting blood lipids and inflammation factors. Current nutrition recommendations emphasise a limitation of dietary TFA intake. The aim of this study was to investigate fatty acid composition in sweet bakery products, with emphasis on TFA, on the Swedish market and compare fatty acid composition over time. Products were sampled in 2001, 2006 and 2007 and analysed for fatty acid composition by using GC. Mean TFA levels were 0.7% in 2007 and 5.9% in 2001 of total fatty acids. In 1995-97, mean TFA level was 14.3%. In 2007, 3 of 41 products had TFA levels above 2% of total fatty acids. TFA content had decreased in this product category, while the proportion of saturated (SFA) and polyunsaturated (PUFA) fatty acids had increased, mostly through increased levels of 16:0 and 18:2 n-6, respectively. The total fat content remained largely unchanged. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

Seasonal variation in the Dutch bovine raw milk composition.

PubMed

Heck, J M L; van Valenberg, H J F; Dijkstra, J; van Hooijdonk, A C M

2009-10-01

In this study, we determined the detailed composition of and seasonal variation in Dutch dairy milk. Raw milk samples representative of the complete Dutch milk supply were collected weekly from February 2005 until February 2006. Large seasonal variation exists in the concentrations of the main components and milk fatty acid composition. Milk lactose concentration was rather constant throughout the season. Milk true protein content was somewhat more responsive to season, with the lowest content in June (3.21 g/100 g) and the highest content in December (3.38 g/100 g). Milk fat concentration increased from a minimum of 4.10 g/100 g in June to a maximum of 4.57 g/100 g in January. The largest (up to 2-fold) seasonal changes in the fatty acid composition were found for trans fatty acids, including conjugated linoleic acid. Milk protein composition was rather constant throughout the season. Milk unsaturation indices, which were used as an indication of desaturase activity, were lowest in spring and highest in autumn. Compared with a previous investigation of Dutch dairy milk in 1992, the fatty acid composition of Dutch raw milk has changed considerably, in particular with a higher content of saturated fatty acids in 2005 milk.

A short-term study on the interaction of bacteria, fungi and endosulfan in soil microcosm.

PubMed

Xie, Huijun; Gao, Fuwei; Tan, Wei; Wang, Shu-Guang

2011-12-15

Endosulfan is one of the few organic chlorine insecticides still in use today in many developing countries. It has medium toxicity for fish and aquatic invertebrates. In this study, we added different concentrations of endosulfan to a series of soil samples collected from Baihua Park in Jinan, Shandong Province, China. Interactions of exogenous endosulfan, bacteria and fungi were analyzed by monitoring the changes in microbe-specific phospholipid fatty acids (PLFA), residual endosulfan and its metabolites which include; endosulfan sulfate, endosulfan lactone and endosulfan diol during a 9 days incubation period. Our results showed that endosulfan reduced fungi biomass by 47% on average after 9 days, while bacteria biomass increased 76% on average. In addition, we found that endosulfan degraded 8.62% in natural soil (NE), 5.51% in strepolin soil (SSE) and 2.47% in sterile soil (SE). Further analysis of the endosulfan metabolites in NE and SSE, revealed that the amount of endosulfan sulfate (ES) significantly increased and that of endosulfan lactone (EL) slightly decreased in both samples after 9 days. However, that of endosulfan diol (ED) increased in NE and decreased in SSE. After collective analysis our data demonstrated that fungi and bacteria responded differently to exogeous endosulfan, in a way that could promote the formation of endosulfan diol during endosulfan degradation. Copyright © 2011 Elsevier B.V. All rights reserved.

Operational performance, biomass and microbial community structure: impacts of backwashing on drinking water biofilter.

PubMed

Liao, Xiaobin; Chen, Chao; Zhang, Jingxu; Dai, Yu; Zhang, Xiaojian; Xie, Shuguang

2015-01-01

Biofiltration has been widely used to reduce organic matter and control the formation of disinfection by-products in drinking water. Backwashing might affect the biofilters' performance and the attached microbiota on filter medium. In this study, the impacts of backwashing on the removal of dissolved organic carbon (DOC), dissolved organic nitrogen (DON) and N-nitrosamine precursors by a pilot-scale biological activated carbon (BAC) filtration system were investigated. The impacts of backwashing on biomass and microbial community structure of BAC biofilm were also investigated. Phospholipid fatty acid (PLFA) analysis showed that backwashing reduced nearly half of the attached biomass on granular activated carbon (GAC) particles, followed by a recovery to the pre-backwashing biomass concentration in 2 days after backwashing. Backwashing was found to transitionally improve the removal of DOC, DON and N-nitrosamine precursors. MiSeq sequencing analysis revealed that backwashing had a strong impact on the bacterial diversity and community structure of BAC biofilm, but they could gradually recover with the operating time after backwashing. Phylum Proteobacteria was the largest bacterial group in BAC biofilm. Microorganisms from genera Bradyrhizobium, Hyphomicrobium, Microcystis and Sphingobium might contribute to the effective removal of nitrogenous organic compounds by drinking water biofilter. This work could add some new insights towards the operation of drinking water biofilters and the biological removal of organic matter.

[Soil microbial community structure in Picea asperata plantations with different ages in subalpine of western Sichuan, Southwest China.

PubMed

Luo, Da; Liu, Shun; Shi, Zuo Min; Feng, Qiu Hong; Liu, Qian Li; Zhang, Li; Huang, Quan; He, Jian She

2017-02-01

The effects of four Picea asperata plantations with different ages (50-, 38-, 27- and 20-year-old), in subalpine of western Sichuan, on the characteristics of soil microbial diversity and microbial community structure were studied by the method of phospholipid fatty acid (PLFA) profiles. The results showed that, with the increase of age, the contents of soil organic carbon and total nitrogen gradually improved, while Shannon's diversity index and Pielou's evenness index of soil microorganisms increased at first and then decreased. The amounts of microbial total PLFAs, bacterial PLFAs, fungal PLFAs, actinobacterial PLFAs, and arbuscular mycorrhizal fungal (AMF) PLFAs in soils consistently increased with increasing age. The principal component analysis (PCA) indicated that the soil microbial communities in different plantations were structurally distinct from each other. The first principal component (PC1) and the second principal component (PC2) together accounted for 66.8% of total variation of the soil microbial community structure. The redundancy analysis (RDA) of soil microbial community structure and environmental factors showed that soil organic carbon, total nitrogen, total potassium, and fine root mass were the key determinants influencing the microbial community structure. Our study suggested that, with the extension of artificialafforestation time, the soil fertility and microbial biomass were enhanced, and the restoration processes of forest ecosystem were stable.

Nutrient leaching, soil pH and changes in microbial community increase with time in lead-contaminated boreal forest soil at a shooting range area.

PubMed

Selonen, Salla; Setälä, Heikki

2017-02-01

Despite the known toxicity of lead (Pb), Pb pellets are widely used at shotgun shooting ranges over the world. However, the impacts of Pb on soil nutrients and soil microbes, playing a crucial role in nutrient cycling, are poorly understood. Furthermore, it is unknown whether these impacts change with time after the cessation of shooting. To shed light on these issues, three study sites in the same coniferous forest in a shooting range area were studied: an uncontaminated control site and an active and an abandoned shooting range, both sharing a similar Pb pellet load in the soil, but the latter with a 20-year longer contamination history. Soil pH and nitrate concentration increased, whilst soil phosphate concentration and fungal phospholipid fatty acid (PLFA) decreased due to Pb contamination. Our results imply that shooting-derived Pb can influence soil nutrients and microbes not only directly but also indirectly by increasing soil pH. However, these mechanisms cannot be differentiated here. Many of the Pb-induced changes were most pronounced at the abandoned range, and nutrient leaching was increased only at that site. These results suggest that Pb disturbs the structure and functions of the soil system and impairs a crucial ecosystem service, the ability to retain nutrients. Furthermore, the risks of shooting-derived Pb to the environment increase with time.

Characterizing the intrinsic bioremediation potential of 1,4-dioxane and trichloroethene using innovative environmental diagnostic tools.

PubMed

Chiang, Sheau-Yun Dora; Mora, Rebecca; Diguiseppi, William H; Davis, Greg; Sublette, Kerry; Gedalanga, Phillip; Mahendra, Shaily

2012-09-01

An intrinsic biodegradation study involving the design and implementation of innovative environmental diagnostic tools was conducted to evaluate whether monitored natural attenuation (MNA) could be considered as part of the remedial strategy to treat an aerobic aquifer contaminated with 1,4-dioxane and trichloroethene (TCE). In this study, advanced molecular biological and stable isotopic tools were applied to confirm in situ intrinsic biodegradation of 1,4-dioxane and TCE. Analyses of Bio-Trap® samplers and groundwater samples collected from monitoring wells verified the abundance of bacteria and enzymes capable of aerobically degrading TCE and 1,4-dioxane. Furthermore, phospholipid fatty acid analysis with stable isotope probes (PLFA-SIP) of the microbial community validated the ability for microbial degradation of TCE and 1,4-dioxane. Compound specific isotope analysis (CSIA) of groundwater samples for TCE resulted in δ(13)C values that indicated likely biodegradation of TCE in three of the four monitoring wells sampled. Results of the MNA evaluation showed that enzymes capable of aerobically degrading TCE and 1,4-dioxane were present, abundant, and active in the aquifer. Taken together, these results provide direct evidence of the occurrence of TCE and 1,4-dioxane biodegradation at the study site, supporting the selection of MNA as part of the final remedy at some point in the future.

Challenges of including nitrogen effects on decomposition in earth system models

NASA Astrophysics Data System (ADS)

Hobbie, S. E.

2011-12-01

Despite the importance of litter decomposition for ecosystem fertility and carbon balance, key uncertainties remain about how this fundamental process is affected by nitrogen (N) availability. Nevertheless, resolving such uncertainties is critical for mechanistic inclusion of such processes in earth system models, towards predicting the ecosystem consequences of increased anthropogenic reactive N. Towards that end, we have conducted a series of experiments examining nitrogen effects on litter decomposition. We found that both substrate N and externally supplied N (regardless of form) accelerated the initial decomposition rate. Faster initial decomposition rates were linked to the higher activity of carbohydrate-degrading enzymes associated with externally supplied N and the greater relative abundances of Gram negative and Gram positive bacteria associated with green leaves and externally supplied organic N (assessed using phospholipid fatty acid analysis, PLFA). By contrast, later in decomposition, externally supplied N slowed decomposition, increasing the fraction of slowly decomposing litter and reducing lignin-degrading enzyme activity and relative abundances of Gram negative and Gram positive bacteria. Our results suggest that elevated atmospheric N deposition may have contrasting effects on the dynamics of different soil carbon pools, decreasing mean residence times of active fractions comprising very fresh litter, while increasing those of more slowly decomposing fractions including more processed litter. Incorporating these contrasting effects of N on decomposition processes into models is complicated by lingering uncertainties about how these effects generalize across ecosystems and substrates.

The luminescent properties of polyethylene films with admixtures of luminophores based on europium compounds

NASA Astrophysics Data System (ADS)

Kalinovskaya, I. V.; Zadorozhnaya, A. N.; Karasev, V. E.

2008-11-01

Polyethylene films activated with europium(III) complexes with carboxylic acids and Eu(L)3 · nD · xH2O + ANT compositions, where L is the trifluoroacetic, toluyl, or cinnamic acid anion and ANT is anthranilic acid, were prepared. The intensity of luminescence of the polymeric compositions depended on the content of luminophores (molar ratio between europium compounds and anthranilic acid). An analysis of the excitation spectra showed that, in polymer—Eu(L)3 · nPhen · xH2O + ANT compositions, there was effective energy transfer from phenanthroline to anthranilic acid levels.

Fatty acids composition of Spanish black (Morus nigra L.) and white (Morus alba L.) mulberries.

PubMed

Sánchez-Salcedo, Eva M; Sendra, Esther; Carbonell-Barrachina, Ángel A; Martínez, Juan José; Hernández, Francisca

2016-01-01

This research has determined qualitatively and quantitatively the fatty acids composition of white (Morus alba) and black (Morus nigra) fruits grown in Spain, in 2013 and 2014. Four clones of each species were studied. Fourteen fatty acids were identified and quantified in mulberry fruits. The most abundant fatty acids were linoleic (C18:2), palmitic (C16:0), oleic (C18:1), and stearic (C18:0) acids in both species. The main fatty acid in all clones was linoleic (C18:2), that ranged from 69.66% (MN2) to 78.02% (MA1) of the total fatty acid content; consequently Spanish mulberry fruits were found to be rich in linoleic acid, which is an essential fatty acid. The fatty acid composition of mulberries highlights the nutritional and health benefits of their consumption. Copyright © 2015 Elsevier Ltd. All rights reserved.

Metal-polymer composites comprising nanostructures and applications thereof

DOEpatents

Wang, Hsing-Lin [Los Alamos, NM; Jeon, Sea Ho [Dracut, MA; Mack, Nathan H [Los Alamos, NM

2011-08-02

Metal-polymer composites, and methods of making and use thereof, said composites comprising a thermally-cured dense polyaniline substrate; an acid dopant; and, metal nanostructure deposits wherein the deposits have a morphology dependent upon the acid dopant.

Metal-polymer composites comprising nanostructures and applications thereof

DOEpatents

Wang, Hsing-Lin [Los Alamos, NM; Jeon, Sea Ho [Dracut, MA; Mack, Nathan H [Los Alamos, NM

2012-04-03

Metal-polymer composites, and methods of making and use thereof, said composites comprising a thermally-cured dense polyaniline substrate; an acid dopant; and, metal nanostructure deposits wherein the deposits have a morphology dependent upon the acid dopant.

Biogeochemistry of mercury in soils and sediments in a mining-impacted watershed, California

NASA Astrophysics Data System (ADS)

Holloway, J. M.; Goldhaber, M. B.

2004-12-01

The East Davis Creek watershed, located in the California Coast Ranges, is host to historic mines that provided mercury for recovery of gold in the Sierra Nevada goldfields in the mid-to-late 1800s. Bedrock in this watershed includes marine sedimentary rock, serpentinite, and hydrothermally altered serpentinite. Cinnabar (HgS) found in the altered serpentinite is the primary ore mineral for mercury. We evaluated the hypothesis that mercury is sequestered in soil organic matter downstream from source areas, releasing a fraction as water-soluble methylmercury. Microbial biomass and the presence of sulfur-reducing bacteria implicated in mercury methylation were quantified using phospholipid fatty acid (PLFA) data. Methylation incubations were performed on soil and sediment inoculated with water from Davis Creek Reservoir and sealed in glass containers under an anoxic headspace for 21 days. Methylmercury was measured on extracts of the soils at the start and at the end of the incubation period. Two sources of mercury to stream sediments, a soil with an altered serpentinite parent and mine tailings, were incubated. Stream sediment, an overbank deposit soil and a wetland soil forming from these sediments were also incubated. The overbank deposit soil is periodically flooded. The wetland soil around the edge of Davis Creek Reservoir is perennially saturated with water. The altered serpentinite soil and mine tailings had the highest total mercury concentrations (170 and 150 ng Hg /g, respectively). Total mercury concentrations in stream sediments are low (¡Ü1 ng Hg/g), with higher mercury concentrations in the overbank (3 ng/g) and wetland soils (18 ng Hg/g). Mercury leached from altered serpentinite soils and mine tailings may be transported downstream and sequestered through sorption to organic matter in the overbank and wetland soils. PLFA biomarkers for Desulfobacter (10Me16:0) and Desulfovibrio (i17:1) were present in all incubated materials, with lower concentrations in mine tailings and stream sediment relative to the three soils examined. Methylmercury was initially present in greater concentrations in the overbank deposit (23 ng HgMe/g) soils. The elevated methyl mercury in the overbank deposit soil may be due to the greater biomass of sulfur reducing bacteria indicated by the 10Me16:0 and i17:1 biomarkers. During the 21-day incubation, methylmercury increased from 0.6 to 15 ng HgMe/g in the wetland soil concomitantly with sulfate decreasing from 130 to 7.0 mg SO4=/g. Methylmercury concentrations did not change appreciably in the other soils, although sulfate decreased from 19 to 2.0 mg SO4=/g in the overbank deposit soil. These data suggest that overbank deposits and wetland soils sequester mercury leached from upstream sources, with a fraction of this mercury released through microbial methylation.

[FATTY ACID COMPOSITION ALTEROMONAS-LIKE BACTERIA ISOLATED FROM THE BLACK SEA WATER].

PubMed

Klochko, V V; Avdeeva, L V

2015-01-01

Alteromonas macleodii strains isolated from the Black sea water were similar in their fatty acids composition with the type strain of this species. Analysis of lipid composition of 10 A. macleodii strains isolated from the deep and surface water layers in different World ocean regions including the Black sea water has shown that the deep and surface isolates of this species formed two groups different in their fatty acids profiles. The Black sea isolates of Pseudoalteromonas haloplanktis, P. citrea, P. flavipulchra conformed to these species type strains in their fatty acids composition. On the basis of the fatty acids spectra similarity of three Pseudoalteromonas species strains with Plipolytica described in 2010 has been established. Presence of three isomers C16:1ψ7, C 16:1ψ9 and C16:1ψ6--components of hexadecenic acid in the Black sea isolates of Shewanella baltica has been shown.

Changes in fatty acid and hydrocarbon composition of zooplankton assemblages related to environmental conditions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lambert, R.M.

1989-01-01

Changes in zooplankton fatty acid and hydrocarbon patterns are described in relation to changes in environmental conditions and species composition. The regulation of zooplankton abundance by sea nettle-ctenophore interaction was examined in a small Rhode Island coastal pond. Sea nettles were nettles were able to eliminate ctenophores from the pond and subsequently zooplankton abundance increased. During one increase in zooplankton abundance, it was found that polyunsaturated fatty acids decreased while monounsaturated fatty acids increased. It was concluded that this shift in biochemical pattern was due to food limitation. In addition, zooplankton fatty acids were used in multivariate discriminant analysis tomore » classify whether zooplankton were from coastal or estuarine environments. Zooplankton from coastal environments were characterized by higher monounsaturate fatty acids. Zooplankton hydrocarbon composition was affected by species composition and by pollution inputs. The presence of Calanus finmarchicus was detected by increased levels of pristane.« less

EFFECT OF TEMPERATURE ON THE COMPOSITION OF FATTY ACIDS IN ESCHERICHIA COLI

PubMed Central

Marr, Allen G.; Ingraham, John L.

1962-01-01

Marr, Allen G. (University of California, Davis) and John L. Ingraham. Effect of temperature on composition of fatty acids in Escherichia coli. J. Bacteriol. 84:1260–1267. 1962.—Variations in the temperature of growth and in the composition of the medium alter the proportions of individual fatty acids in the lipids of Escherichia coli. As the temperature of growth is lowered, the proportion of unsaturated fatty acids (hexadecenoic and octadecenoic acids) increases. The increase in content of unsaturated acids with a decrease in temperature of growth occurs in both minimal and complex media. Cells harvested in the stationary phase contained large amounts of cyclopropane fatty acids (methylenehexadecanoic and methylene octadecanoic acids) in comparison with cells harvested during exponential growth. Cells grown in a chemostat, limited by the concentration of ammonium salts, show a much higher content of saturated fatty acids (principally palmitic acid) than do cells harvested from an exponentially-growing batch culture in the same medium. Cells grown in a chemostat, limited by the concentration of glucose, show a slightly higher content of unsaturated fatty acids than cells from the corresponding batch culture. The results do not indicate a direct relation between fatty acid composition and minimal growth temperature. PMID:16561982

Serum, cheek cell and breast milk fatty acid compositions in infants with atopic and non-atopic eczema.

PubMed

Laitinen, K; Sallinen, J; Linderborg, K; Isolauri, E

2006-02-01

The major theory implicating diet with allergic diseases is associated with altered food consumption and subsequent changes in fatty acid composition. To investigate fatty acid compositions among infants with atopic and non-atopic eczema and healthy infants and to evaluate the expediency of non-invasive cheek cell phospholipid fatty acid composition as a marker in patients with eczema. Diagnosis of eczema in infants was confirmed clinically and by positive (atopic eczema, n=6) or negative (non-atopic eczema, n=6) skin prick testing in comparison with controls (n=19). The fatty acid compositions of infant cheek cell and serum phospholipids and breast milk total lipids were analysed by gas chromatography. The distinction between atopic and non-atopic eczema was manifested in cheek cell phospholipids as linoleic acid (14.69 (13.67-15.53)% of total fatty acids; the median (interquartile range)), the sum of n-6 fatty acids (19.94 (19.06-20.53)%) and the sum of polyunsaturated fatty acids (22.70 (21.31-23.28)%) were higher in infants with atopic eczema compared with non-atopic eczema (12.69 (10.87-13.93); 17.72 (15.63-18.91) and 19.90 (17.64-21.06), respectively; P<0.05) and controls (12.50 (12.16-13.42); 18.19 (17.43-18.70) and 20.32 (19.32-21.03), respectively; P<0.05). Serum phospholipid gamma-linolenic acid was lower in both atopic and non-atopic eczema compared with controls (P<0.05) and additionally eicosapentaenoic acid was higher in atopic eczema compared with controls (P<0.05). These preliminary results suggest differences in fatty acid compositions between the two types of eczema, calling for further evaluation in a larger setting. The two types of eczema may be regulated by different immunological processes, and fatty acids may have a more profound role in the atopic type.

[Apply fourier transform infrared spectra coupled with two-dimensional correlation analysis to study the evolution of humic acids during composting].

PubMed

Bu, Gui-jun; Yu, Jing; Di, Hui-hui; Luo, Shi-jia; Zhou, Da-zhai; Xiao, Qiang

2015-02-01

The composition and structure of humic acids formed during composting play an important influence on the quality and mature of compost. In order to explore the composition and evolution mechanism, municipal solid wastes were collected to compost and humic and fulvic acids were obtained from these composted municipal solid wastes. Furthermore, fourier transform infrared spectra and two-dimensional correlation analysis were applied to study the composition and transformation of humic and fulvic acids during composting. The results from fourier transform infrared spectra showed that, the composition of humic acids was complex, and several absorbance peaks were observed at 2917-2924, 2844-2852, 2549, 1662, 1622, 1566, 1454, 1398, 1351, 990-1063, 839 and 711 cm(-1). Compared to humic acids, the composition of fulvci acids was simple, and only three peaks were detected at 1725, 1637 and 990 cm(-1). The appearance of these peaks showed that both humic and fulvic acids comprised the benzene originated from lignin and the polysaccharide. In addition, humic acids comprised a large number of aliphatic and protein which were hardly detected in fulvic acids. Aliphatic, polysaccharide, protein and lignin all were degraded during composting, however, the order of degradation was different between humic and fulvci acids. The result from two-dimensional correlation analysis showed that, organic compounds in humic acids were degraded in the following sequence: aliphatic> protein> polysaccharide and lignin, while that in fulvic acids was as following: protein> polysaccharide and aliphatic. A large number of carboxyl, alcohols and ethers were formed during the degradation process, and the carboxyl was transformed into carbonates. It can be concluded that, fourier transform infrared spectra coupled with two-dimensional correlation analysis not only can analyze the function group composition of humic substances, but also can characterize effectively the degradation sequence of these groups and identified the formation mechanism and dynamics of humic substances during composting.

Environmentally benign graphite intercalation compound composition for exfoliated graphite, flexible graphite, and nano-scaled graphene platelets

DOEpatents

Zhamu, Aruna; Jang, Bor Z.

2014-06-17

A carboxylic-intercalated graphite compound composition for the production of exfoliated graphite, flexible graphite, or nano-scaled graphene platelets. The composition comprises a layered graphite with interlayer spaces or interstices and a carboxylic acid residing in at least one of the interstices, wherein the composition is prepared by a chemical oxidation reaction which uses a combination of a carboxylic acid and hydrogen peroxide as an intercalate source. Alternatively, the composition may be prepared by an electrochemical reaction, which uses a carboxylic acid as both an electrolyte and an intercalate source. Exfoliation of the invented composition does not release undesirable chemical contaminants into air or drainage.

Fatty acid composition in serum correlates with that in the liver and non-alcoholic fatty liver disease activity scores in mice fed a high-fat diet.

PubMed

Wang, Xing-He; Li, Chun-Yan; Muhammad, Ishfaq; Zhang, Xiu-Ying

2016-06-01

In this study, we investigated the correlation between the serum fatty acid composition and hepatic steatosis, inflammation, hepatocellular ballooning scores, and liver fatty acids composition in mice fed a high-fat diet. Livers were collected for non-alcoholic fatty liver disease score analysis. Fatty acid compositions were analysed by gas chromatography. Correlations were determined by Pearson correlation coefficient. Exposed to a high-fat diet, mice developed fatty liver disease with varying severity without fibrosis. The serum fatty acid variation became more severe with prolonged exposure to a high-fat diet. This variation also correlated significantly with the variation in livers, with the types of fatty acids corresponding to liver steatosis, inflammation, and hepatocellular ballooning scores. Results of this study lead to the following hypothesis: the extent of serum fatty acid variation may be a preliminary biomarker of fatty liver disease caused by high-fat intake. Copyright © 2016. Published by Elsevier B.V.

Improved fatty acid analysis of conjugated linoleic acid rich egg yolk triacylglycerols and phospholipid species.

PubMed

Shinn, Sara; Liyanage, Rohana; Lay, Jack; Proctor, Andrew

2014-07-16

Reports from chicken conjugated linoleic acid (CLA) feeding trials are limited to yolk total fatty acid composition, which consistently described increased saturated fatty acids and decreased monounsaturated fatty acids. However, information on CLA triacylglycerol (TAG) and phospholipid (PL) species is limited. This study determined the fatty acid composition of total lipids in CLA-rich egg yolk produced with CLA-rich soy oil, relative to control yolks using gas chromatography with flame ionization detection (GC-FID), determined TAG and PL fatty acid compositions by thin-layer chromatography-GC-FID (TLC-GC-FID), identified intact PL and TAG species by TLC-matrix-assisted laser desorption/ionization mass spectrometry (TLC-MALDI-MS), and determined the composition of TAG and PL species in CLA and control yolks by direct flow infusion electrospray ionization MS (DFI ESI-MS). In total, 2 lyso-phosphatidyl choline (LPC) species, 1 sphingomyelin species, 17 phosphatidyl choline species, 19 TAG species, and 9 phosphatidyl ethanolamine species were identified. Fifty percent of CLA was found in TAG, occurring predominantly in C52:5 and C52:4 TAG species. CLA-rich yolks contained significantly more LPC than did control eggs. Comprehensive lipid profiling may provide insight on relationships between lipid composition and the functional properties of CLA-rich eggs.

[The changes in contents and composition of phenolic acids during cell xylem growth in scots pine].

PubMed

Antonova, G F; Zheliznichenko, T V; Stasova, V V

2011-01-01

The contents and composition of alcohol soluble phenolic acids were studied during cell xylem growth in the course of wood annual increment formation in the stems of Scots pine. The cells of cambium zone, of two stages of expansion growth and the outset of secondary thickening zone (before lignification) were successively gathered from the stem segments of 25-old pine trees in the period of earlywood xylem formation with constant anatomical and histochemical control. The contents of free and bound forms of phenolic acids, isolated by 80% ethanol from tissues, as well as of their ethers and esters were calculated both per dry weight and per cell. The content and relation of the fractions and the composition of phenolic acid have been found to change significantly from cambium zone to the outset of tracheid secondary thickening. The character of the variations depends on a calculation method. According to the calculation per cell the amount of free and bound phenolic acids and in their composition of esters and especially ethers increased at the first step of expansion growth zone, decreased at the second one and rose again in the outset of secondary wall deposition. In dependence on the stage of cell development the pool of bound phenolic acids exceeded of free acid pool in 2-5 times. Sinapic and ferulic acids dominated in the composition of free hydroxycinnamic acids. The content and composition of hydroxycinnamic acids in ethers and esters depended on cell development phase. In cambium p-coumaric and sinapic acids were principal aglycons in ethers, at other stages these were sinapic and caffeic acids. The esters in cambium zone included essentially p-coumaric acid and at the other stages - sinapic and ferulic acids. At the first phase of growth benzoic acid was connected principally by ester bonds. The pool of these esters decreased from the first phase of growth to the outset of cell wall thickening and in proportion to this the level of free benzoic acid rose.

Effect of supplementation with linseed or a blend of aromatic spices and time on feed on fatty acid composition, meat quality and consumer liking of meat from lambs fed dehydrated alfalfa or corn.

PubMed

Realini, C E; Bianchi, G; Bentancur, O; Garibotto, G

2017-05-01

Cross-bred lambs (n=72) were fed finishing diets using a factorial arrangement of treatments: BASAL DIET (alfalfa pellets or corn), SUPPLEMENT (none, linseed or aromatic spices), TIME ON FEED (41 or 83days). Carcass and meat quality traits, fatty acid composition, color stability and consumer liking were determined. Feeding alfalfa improved sensory ratings and fatty acid composition of lamb. However, corn or longer alfalfa feeding would be recommended if heavier and fatter carcasses are sought. Consumer liking and fatty acid composition of lamb were improved with addition of spices and linseed, respectively. But additional antioxidant strategies should be considered to delay meat color deterioration during storage if lambs are fed corn-linseed for 83days. Although alfalfa basal diet and linseed supplementation improved fatty acid composition, feeding the basal diets for at least 41days resulted in low n-3 fatty acid concentrations in muscle. Copyright © 2017 Elsevier Ltd. All rights reserved.

Quantification of phenolic acids and antioxidant potential of inbred, hybrid and composite cultivars of maize under different nitrogen regimes.

PubMed

Ganie, Arshid Hussain; Yousuf, Peerzada Yasir; Ahad, Amjid; Pandey, Renu; Ahmad, Sayeed; Aref, Ibrahim M; Noor, Jewel Jameeta; Iqbal, Muhammad

2016-11-01

Maize (Zea mays L.) is a multipurpose crop, which is immensely used worldwide for its nutritional as well as medicinal properties. This study evaluates the effect of varying concentrations of nitrogen (N) on accumulation of phenolic acids and antioxidant activity in different maize cultivars, including inbreds, hybrids and a composite, which were grown in natural light under controlled temperature (30°C/20°C D/N) and humidity (80%), with sufficient (4.5mM) and low (0.05mM) nitrogen supply. Seeds of different cultivars were powdered and extracted in a methanol:water (80:20) mixture through reflux at 60-75°C, and the extracts obtained were subjected to high performance thin layer chromatography (HPTLC), using ethyl acetate: acetic acid: formic acid: water (109:16:12:31) solvent system for the separation of phenolic acids. Antioxidant activity of the extracts was determined by 2,2-diphenyl-1-picrylhydrazyl (DPPH) and H2O2-scavenging activity assays. At sufficient nitrogen condition, the contents of different phenolic acids were higher in the composite cultivar (8.7 mg g-1 d.wt. in gallic acid to 39.3 mg g-1 d.wt. in cinnamic and salicylic acids) than in inbreds and hybrids. Under low nitrogen condition, the phenolic acids contents declined significantly in inbreds and hybrids, but remained almost unaffected in the composite. The antioxidant activity was also the maximum in the composite, and declined similarly as phenolic acids under low nitrogen supply, showing a significant reduction in inbreds and hybrids only. Therefore, the maize composite has a potential for being used as a nutraceutical in human-health sector.

Compositional analyses and shelf-life modeling of njangsa (ricinodendron heudelotii)seed oil using the weibull hazard method

USDA-ARS?s Scientific Manuscript database

This study investigated the compositional characteristics and shelf-life of Njangsa seed oil (NSO). Oil from Njangsa had a high polyunsaturated fatty acid (PUFA) content of which alpha eleosteric acid (alpha-ESA), an unusual conjugated linoleic acid was the most prevalent (about 52%). Linoleic acid...

The fatty acid composition of a Vibrio alginolyticus associated with the alga Cladophora coelothrix. Identification of the novel 9-methyl-10-hexadecenoic acid.

PubMed

Carballeira, N M; Sostre, A; Stefanov, K; Popov, S; Kujumgiev, A; Dimitrova-Konaklieva, S; Tosteson, C G; Tosteson, T R

1997-12-01

The fatty acid composition of a new strain of Vibrio alginolyticus, found in the alga Cladophora coelothrix, was studied. Among 38 different fatty acids, a new fatty acid, 9-methyl-10-hexadecenoic acid and the unusual 11-methyl-12-octadecenoic acid, were identified. Linear alkylbenzene fatty acids, such as 10-phenyldecanoic acid, 12-phenyldodecanoic acid and 14-phenyltetradecanoic acid, were also found in V. alginolyticus. The alga contained 43% saturated fatty acids, and 28% C16-C20 polyunsaturated fatty acids of the n-3 and n-6 families.

A comparative study of the fatty acid composition of prochloron lipids

NASA Technical Reports Server (NTRS)

Kenrick, J. R.; Deane, E. M.; Bishop, D. G.

1983-01-01

The chemical analysis of lipids of Prochloron isolated from several hosts is discussed. The object was to determine whether differences in lipid composition could be used to characterize organisms from different sources. Major lipid components are given. An analysis of fatty acid composition of individual lipids slowed a distinctive disstribution of fatty acids. While present results do not justify the use of fatty acid content in the taxonomy of Prochlon, the variations found in the lipids of cells from the same host harvested from different areas, or at different times in the same area, suggest that a study of the effects of temperature and light intensity on lipid composition would be rewarding.

The uniqueness of humic substances in each of soil, stream and marine environments

USGS Publications Warehouse

Malcolm, R.L.

1990-01-01

Definitive compositional differences are shown to exist for both fulvic acids and humic acids from soil, stream and marine environments by five different methods (1H and 13C NMR spectroscopy, 14C age and ?? 13C isotopic analyses, amino acid analyses and pyrolysis-mass spectrometry). Definitive differences are also found between fulvic acids and humic acids within each environment. These differences among humic substances from various sources are more readily discerned because the method employed for the isolation of humic substances from all environments excludes most of the non-humic components and results in more purified humic isolates from water and soils. The major compositional aspects of fulvic acids and humic acids which determine the observed characteristic differences in each environment are the amounts and compositions of saccharide, phenolic, methoxyl, aromatic, hydrocarbon, amino acid and nitrogen moieties.

Detailed dimethylacetal and fatty acid composition of rumen content from lambs fed lucerne or concentrate supplemented with soybean oil.

PubMed

Alves, Susana P; Santos-Silva, José; Cabrita, Ana R J; Fonseca, António J M; Bessa, Rui J B

2013-01-01

Lipid metabolism in the rumen is responsible for the complex fatty acid profile of rumen outflow compared with the dietary fatty acid composition, contributing to the lipid profile of ruminant products. A method for the detailed dimethylacetal and fatty acid analysis of rumen contents was developed and applied to rumen content collected from lambs fed lucerne or concentrate based diets supplemented with soybean oil. The methodological approach developed consisted on a basic/acid direct transesterification followed by thin-layer chromatography to isolate fatty acid methyl esters from dimethylacetal, oxo- fatty acid and fatty acid dimethylesters. The dimethylacetal composition was quite similar to the fatty acid composition, presenting even-, odd- and branched-chain structures. Total and individual odd- and branched-chain dimethylacetals were mostly affected by basal diet. The presence of 18:1 dimethylacetals indicates that biohydrogenation intermediates might be incorporated in structural microbial lipids. Moreover, medium-chain fatty acid dimethylesters were identified for the first time in the rumen content despite their concentration being relatively low. The fatty acids containing 18 carbon-chain lengths comprise the majority of the fatty acids present in the rumen content, most of them being biohydrogenation intermediates of 18:2n-6 and 18:3n-3. Additionally, three oxo- fatty acids were identified in rumen samples, and 16-O-18:0 might be produced during biohydrogenation of the 18:3n-3.

Fatty Acid Composition of Novel Host Jack Pine Do Not Prevent Host Acceptance and Colonization by the Invasive Mountain Pine Beetle and Its Symbiotic Fungus

PubMed Central

Ishangulyyeva, Guncha; Najar, Ahmed; Curtis, Jonathan M.

2016-01-01

Fatty acids are major components of plant lipids and can affect growth and development of insect herbivores. Despite a large literature examining the roles of fatty acids in conifers, relatively few studies have tested the effects of fatty acids on insect herbivores and their microbial symbionts. Particularly, whether fatty acids can affect the suitability of conifers for insect herbivores has never been studied before. Thus, we evaluated if composition of fatty acids impede or facilitate colonization of jack pine (Pinus banksiana) by the invasive mountain pine beetle (Dendroctonus ponderosae) and its symbiotic fungus (Grosmannia clavigera). This is the first study to examine the effects of tree fatty acids on any bark beetle species and its symbiotic fungus. In a novel bioassay, we found that plant tissues (hosts and non-host) amended with synthetic fatty acids at concentrations representative of jack pine were compatible with beetle larvae. Likewise, G. clavigera grew in media amended with lipid fractions or synthetic fatty acids at concentrations present in jack pine. In contrast, fatty acids and lipid composition of a non-host were not suitable for the beetle larvae or the fungus. Apparently, concentrations of individual, rather than total, fatty acids determined the suitability of jack pine. Furthermore, sampling of host and non-host tree species across Canada demonstrated that the composition of jack pine fatty acids was similar to the different populations of beetle’s historical hosts. These results demonstrate that fatty acids composition compatible with insect herbivores and their microbial symbionts can be important factor defining host suitability to invasive insects. PMID:27583820

Fatty acids in berry lipids of six sea buckthorn (Hippophae rhamnoides L., subspecies carpatica) cultivars grown in Romania

PubMed Central

2012-01-01

Background A systematic mapping of the phytochemical composition of different sea buckthorn (Hippophae rhamnoides L.) fruit subspecies is still lacking. No data relating to the fatty acid composition of main lipid fractions from the berries of ssp. carpatica (Romania) have been previously reported. Results The fatty acid composition of the total lipids (oils) and the major lipid fractions (PL, polar lipids; FFA, free fatty acids; TAG, triacylglycerols and SE, sterol esters) of the oils extracted from different parts of six sea buckthorn berry subspecies (ssp. carpatica) cultivated in Romania were investigated using the gas chromatography-mass spectrometry (GC-MS). The dominating fatty acids in pulp/peel and whole berry oils were palmitic (23-40%), oleic (20-53%) and palmitoleic (11-27%). In contrast to the pulp oils, seed oils had higher amount of polyunsaturated fatty acids (PUFAs) (65-72%). The fatty acid compositions of TAGs were very close to the compositions of corresponding seed and pulp oils. The major fatty acids in PLs of berry pulp/peel oils were oleic (20-40%), palmitic (17-27%), palmitoleic (10-22%) and linoleic (10%-20%) acids, whereas in seeds PLs, PUFAs prevailed. Comparing with the other lipid fractions the SEs had the highest contents of saturated fatty acids (SFAs). The fatty acid profiles of the FFA fractions were relatively similar to those of TAGs. Conclusions All parts of the analyzed sea buckthorn berry cultivars (ssp. carpatica) exhibited higher oil content then the other European or Asiatic sea buckthorn subspecies. Moreover, the pulp/peel oils of ssp. carpatica were found to contain high levels of oleic acid and slightly lower amounts of linoleic and α-linolenic acids. The studied cultivars of sea buckthorn from Romania have proven to be potential sources of valuable oils. PMID:22995716

Fatty acids in berry lipids of six sea buckthorn (Hippophae rhamnoides L., subspecies carpatica) cultivars grown in Romania.

PubMed

Dulf, Francisc V

2012-09-20

A systematic mapping of the phytochemical composition of different sea buckthorn (Hippophae rhamnoides L.) fruit subspecies is still lacking. No data relating to the fatty acid composition of main lipid fractions from the berries of ssp. carpatica (Romania) have been previously reported. The fatty acid composition of the total lipids (oils) and the major lipid fractions (PL, polar lipids; FFA, free fatty acids; TAG, triacylglycerols and SE, sterol esters) of the oils extracted from different parts of six sea buckthorn berry subspecies (ssp. carpatica) cultivated in Romania were investigated using the gas chromatography-mass spectrometry (GC-MS). The dominating fatty acids in pulp/peel and whole berry oils were palmitic (23-40%), oleic (20-53%) and palmitoleic (11-27%). In contrast to the pulp oils, seed oils had higher amount of polyunsaturated fatty acids (PUFAs) (65-72%). The fatty acid compositions of TAGs were very close to the compositions of corresponding seed and pulp oils. The major fatty acids in PLs of berry pulp/peel oils were oleic (20-40%), palmitic (17-27%), palmitoleic (10-22%) and linoleic (10%-20%) acids, whereas in seeds PLs, PUFAs prevailed. Comparing with the other lipid fractions the SEs had the highest contents of saturated fatty acids (SFAs). The fatty acid profiles of the FFA fractions were relatively similar to those of TAGs. All parts of the analyzed sea buckthorn berry cultivars (ssp. carpatica) exhibited higher oil content then the other European or Asiatic sea buckthorn subspecies. Moreover, the pulp/peel oils of ssp. carpatica were found to contain high levels of oleic acid and slightly lower amounts of linoleic and α-linolenic acids. The studied cultivars of sea buckthorn from Romania have proven to be potential sources of valuable oils.

Fatty acid composition of wild mushroom species of order Agaricales--examination by gas chromatography-mass spectrometry and chemometrics.

PubMed

Marekov, Ilko; Momchilova, Svetlana; Grung, Bjørn; Nikolova-Damyanova, Boryana

2012-12-01

Applying gas chromatography-mass spectrometry of 4,4-dimethyloxazoline fatty acid derivatives, the fatty acid composition of 15 mushroom species belonging to 9 genera and 5 families of order Agaricales growing in Bulgaria is determined. The structure of 31 fatty acids (not all present in each species) is unambiguously elucidated, with linoleic, oleic and palmitic acids being the main components (ranging between 70.9% (Marasmius oreades) and 91.2% (Endoptychum agaricoides)). A group of three hexadecenoic positionally isomeric fatty acids, 6-, 9- and 11-16:1, appeared to be characteristic components of the examined species. By applying chemometrics it was possible to show that the fatty acid composition closely reflects the classification of the species. Copyright © 2012 Elsevier B.V. All rights reserved.

Determination of fatty acid composition and quality characteristics of oils from palm fruits using solvent extraction

NASA Astrophysics Data System (ADS)

Kasmin, Hasimah; Lazim, Azwan Mat; Awang, Roila

2015-09-01

Palm oil contains about 45% of saturated palmitic acid and 39% of mono-unsaturated oleic acid. Investigations made in the past to trace the fatty acid composition in palm revealed that ripeness of fresh fruit bunch (FFB) affect oil composition. However, there is no evidence that processing operations affect oil composition, although different stage of processing does affect the quality of oil extracted. An improved method for sterilizing the oil palm fruits by dry heating, followed by oil extraction has been studied. This method eliminates the use of water, thus, increasing the extraction of lipid soluble. The objective of this study is to determine the possibility production of palm oil with different fatty acid composition (FAC) as well as the changes in quality from conventional milling. The unripe and ripe FFB were collected, sterilized and extracted using different method of solvent extraction. Preliminary data have shown that variation in FAC will also alter the physical and chemical properties of the oil extracted.

Properties of polyvinyl alcohol/xylan composite films with citric acid.

PubMed

Wang, Shuaiyang; Ren, Junli; Li, Weiying; Sun, Runcang; Liu, Shijie

2014-03-15

Composite films of xylan and polyvinyl alcohol were produced with citric acid as a new plasticizer or a cross-linking agent. The effects of citric acid content and polyvinyl alcohol/xylan weight ratio on the mechanical properties, thermal stability, solubility, degree of swelling and water vapor permeability of the composite films were investigated. The intermolecular interactions and morphology of composite films were characterized by FTIR spectroscopy and SEM. The results indicated that polyvinyl alcohol/xylan composite films had good compatibility. With an increase in citric acid content from 10% to 50%, the tensile strength reduced from 35.1 to 11.6 MPa. However, the elongation at break increased sharply from 15.1% to 249.5%. The values of water vapor permeability ranged from 2.35 to 2.95 × 10(-7)g/(mm(2)h). Interactions between xylan and polyvinyl alcohol in the presence of citric acid become stronger, which were caused by hydrogen bond and ester bond formation among the components during film forming. Copyright © 2013. Published by Elsevier Ltd.

A Carbon Free Filter for Collection of Large Volume Samples of Cellular Biomass from Oligotrophic Waters

PubMed Central

Mailloux, Brian J.; Dochenetz, Audra; Bishop, Michael; Dong, Hailiang; Ziolkowski, Lori A.; Wommack, K. Eric; Sakowski, Eric G.; Onstott, Tullis C.; Slater, Greg F.

2018-01-01

Isotopic analysis of cellular biomass has greatly improved our understanding of carbon cycling in the environment. Compound specific radiocarbon analysis (CSRA) of cellular biomass is being increasingly applied in a number of fields. However, it is often difficult to collect sufficient cellular biomass for analysis from oligotrophic waters because easy-to-use filtering methods that are free of carbon contaminants do not exist. The goal of this work was to develop a new column based filter to autonomously collect high volume samples of biomass from oligotrophic waters for CSRA using material that can be baked at 450°C to remove potential organic contaminants. A series of filter materials were tested, including uncoated sand, ferrihydrite-coated sand, goethite-coated sand, aluminum-coated sand, uncoated glass wool, ferrihydrite-coated glass wool, and aluminum-coated glass wool, in the lab with 0.1 and 1.0 µm microspheres and E. coli. Results indicated that aluminum-coated glass wool was the most efficient filter and that the retention capacity of the filter far exceeded the biomass requirements for CSRA. Results from laboratory tests indicate that for oligotrophic waters with 1×105 cells ml−1, 117 L of water would need to be filtered to collect 100 µg of PLFA for bulk PLFA analysis and 2000 L for analysis of individual PLFAs. For field sampling, filtration tests on South African mine water indicated that after filtering 5955 liters, 450 µg of total PLFAs were present, ample biomass for radiocarbon analysis. In summary, we have developed a filter that is easy to use and deploy for collection of biomass for CSRA including total and individual PLFAs. PMID:22561839

Indigenous and Contaminant Microbes in Ultradeep Mines

NASA Technical Reports Server (NTRS)

Onstott, T. C.; Moser, D. P.; Pfiffner, S. M.; Fredrickson, J. K.; Brockman, F. J.; Phelps, T. J.; White, D. C.; Peacock, A.; Balkwill, D.; Hoover, R. B.;

Indigenous and Contaminant Microbes in Ultradeep Mines

NASA Technical Reports Server (NTRS)

Onstott, T. C.; Moser, D. P.; Pfiffner, S. M.; Fredrickson, J. F.; Brockman, F. J.; Phelps, T. J.; White, D. C.; Peacock, A.; Balkwill, D.; Hoover, R.;

Structure of β- N-dimethylamino-4-dodecyloxypropiophenone complexes with di- and polycarboxylic acids

NASA Astrophysics Data System (ADS)

Lebedeva, Tamara L.; Shandryuk, George A.; Sycheva, Tatyana I.; Bezborodov, Vladimir S.; Talroze, Raissa V.; Platé, Nicolai A.

1995-07-01

The type of bonds responsible for the complexation of di- and polyacids with the tertiary amine β- N-dimethylamino-4-dodecyloxypropiophenone is studied by means of FTIR spectroscopy. The complexes are shown to be stable due to strong H-bonding with partial charge transfer. The characteristic composition for complexes of polyacrylic, polymethacrylic and malonic acids is calculated as 2:1 (number of carboxylic groups per number of amine molecules) whereas glutaric acid forms complexes of different composition including 1:1. The characteristic composition results from the structure of the initial acid. The structures of both the characteristic complex and "excess" acid are also discussed.

Impact of region on the composition of milk fatty acids in China.

PubMed

Yang, Yongxin; Wang, Jiaqi; Yuan, Tingjie; Bu, Dengpan; Yang, Jinhui; Zhou, Lingyun; Sun, Peng; Zhang, Juanxia

2013-08-30

Milk composition and its fatty acid profile have received much attention with respect to improving human health. However, limited work has been conducted to assess the composition of milk fat in China, which is the third largest producer of milk in the world. In this study the effects of geographical region and seasonal changes (spring and summer) on the fatty acid composition of milk samples collected from six Chinese farms were investigated. Milk fat and protein contents, as well as some individual fatty acids and five fatty acid groups, were found to be unaffected by season, but they did show significant differences by geographical region. Levels of milk cis-9, trans-11 conjugated linoleic acid decreased in summer and increased in spring, increased in north (Hohhot), northeast (Harbin), north centre (Beijing) and northwest (Xi'an) China and decreased in far northwest (Urumqi) and east (Chuzhou) China. Monounsaturated fatty acids increased in east and northwest China and decreased in northeast China, while polyunsaturated fatty acids increased in far northwest and north centre China and decreased in northeast China. This study provides relevent information that contributes to the understanding of parameters affecting variability of milk fatty acid profiles. © 2012 Society of Chemical Industry.

Profiling Abscisic Acid-Induced Changes in Fatty Acid Composition in Mosses.

PubMed

Shinde, Suhas; Devaiah, Shivakumar; Kilaru, Aruna

2017-01-01

In plants, change in lipid composition is a common response to various abiotic stresses. Lipid constituents of bryophytes are of particular interest as they differ from that of flowering plants. Unlike higher plants, mosses have high content of very long-chain polyunsaturated fatty acids. Such lipids are considered to be important for survival of nonvascular plants. Here, using abscisic acid (ABA )-induced changes in lipid composition in Physcomitrella patens as an example, a protocol for total lipid extraction and quantification by gas chromatography (GC) coupled with flame ionization detector (FID) is described.

Bile resistance in Lactococcus lactis strains varies with cellular fatty acid composition: analysis by using different growth media.

PubMed

Kimoto-Nira, Hiromi; Kobayashi, Miho; Nomura, Masaru; Sasaki, Keisuke; Suzuki, Chise

2009-05-31

Bile resistance is one of the basic characteristics of probiotic bacteria. The aim of this study was to investigate the characteristics of bile resistance in lactococci by studying the relationship between bile resistance and cellular fatty acid composition in lactococcci grown on different media. We determined the bile resistance of 14 strains in lactose-free M17 medium supplemented with either glucose only (GM17) or lactose only (LM17). Gas chromatographic analyses of free lipids extracted from the tested strains were used for determining their fatty acid composition. A correlation analysis of all strains grown in both media revealed significant positive correlations between bile resistance and relative contents of hexadecanoic acid and octadecenoic acid, and negative correlations between bile resistance and relative contents of hexadecenoic acid and C-19 cyclopropane fatty acid. It is also a fact that the fatty acids associated with bile resistance depended on species, strain, and/or growth medium. In L. lactis subsp. cremoris strains grown in GM17 medium, the bile-resistant strains had significantly more octadecenoic acid than the bile-sensitive strains. In LM17 medium, bile-resistant strains had significantly more octadecenoic acid and significantly less C-19 cyclopropane fatty acid than the bile-sensitive strains. In L. lactis subsp. lactis strains, bile resistances of some of the tested strains were altered by growth medium. Some strains were resistant to bile in GM17 medium but sensitive to bile in LM17 medium. Some strains were resistant in both media tested. The strains grown in GM17 medium had significantly more hexadecanoic acid and octadecenoic acid, and significantly less tetradecanoic acid, octadecadienoic acid and C-19 cyclopropane fatty acid than the strains grown in LM17 medium. In conclusion, the fatty acid compositions of the bile-resistant lactococci differed from those of the bile-sensitive ones. More importantly, our data suggest that altering their fatty acid composition (i.e. increased hexadecanoic acid and octadecenoic acid and decreased hexadecenoic acid and C-19 cyclopropane fatty acid) by changing growth conditions may be a useful way to enhance their bile resistance in lactococci.

Microbiota transplantation restores normal fecal bile acid composition in recurrent Clostridium difficile infection.

PubMed

Weingarden, Alexa R; Chen, Chi; Bobr, Aleh; Yao, Dan; Lu, Yuwei; Nelson, Valerie M; Sadowsky, Michael J; Khoruts, Alexander

2014-02-15

Fecal microbiota transplantation (FMT) has emerged as a highly effective therapy for refractory, recurrent Clostridium difficile infection (CDI), which develops following antibiotic treatments. Intestinal microbiota play a critical role in the metabolism of bile acids in the colon, which in turn have major effects on the lifecycle of C. difficile bacteria. We hypothesized that fecal bile acid composition is altered in patients with recurrent CDI and that FMT results in its normalization. General metabolomics and targeted bile acid analyses were performed on fecal extracts from patients with recurrent CDI treated with FMT and their donors. In addition, 16S rRNA gene sequencing was used to determine the bacterial composition of pre- and post-FMT fecal samples. Taxonomic bacterial composition of fecal samples from FMT recipients showed rapid change and became similar to the donor after the procedure. Pre-FMT fecal samples contained high concentrations of primary bile acids and bile salts, while secondary bile acids were nearly undetectable. In contrast, post-FMT fecal samples contained mostly secondary bile acids, as did non-CDI donor samples. Therefore, our analysis showed that FMT resulted in normalization of fecal bacterial community structure and metabolic composition. Importantly, metabolism of bile salts and primary bile acids to secondary bile acids is disrupted in patients with recurrent CDI, and FMT corrects this abnormality. Since individual bile salts and bile acids have pro-germinant and inhibitory activities, the changes suggest that correction of bile acid metabolism is likely a major mechanism by which FMT results in a cure and prevents recurrence of CDI.

A novel polymorphism in the oxytocin receptor encoding gene (OXTR) affects milk fatty acid composition in Italian Mediterranean river buffalo.

PubMed

Cosenza, Gianfranco; Macciotta, Nicolò P P; Nudda, Anna; Coletta, Angelo; Ramunno, Luigi; Pauciullo, Alfredo

2017-05-01

The oxytocin receptor, also known as OXTR, is a protein which functions as receptor for the hormone and neurotransmitter oxytocin and the complex oxytocin-oxytocin receptor plays an important role in the uterus during calving. A characterisation of the river buffalo OXTR gene, amino acid sequences and phylogenetic analysis is presented. The DNA regions of the OXTR gene spanning exons 1, 2 and 3 of ten Mediterranean river buffalo DNA samples were analysed and 7 single nucleotide polymorphisms were found. We focused on the g.129C > T SNP detected in exon 3 and responsible for the amino acid replacement CGCArg > TGCCys in position 353. The relative frequency of T allele was of 0·257. An association study between this detected polymorphism and milk fatty acids composition in Italian Mediterranean river buffalo was carried out. The fatty acid composition traits, fatty acid classes and fat percentage of 306 individual milk samples were determined. Associations between OXTR g.129C > T genotype and milk fatty acids composition were tested using a mixed linear model. The OXTR CC genotype was found significantly associated with higher contents of odd branched-chain fatty acids (OBCFA) (P < 0·0006), polyunsaturated FA (PUFA n 3 and n 6) (P < 0·0032 and P < 0·0006, respectively), stearic acid (C18) (P < 0·02) and lower level of palmitic acid (C16) (P < 0·02). The results of this study suggest that the OXTR CC animals might be useful in selection toward the improvement of milk fatty acid composition.

Effects of oleic acid surface coating on the properties of nickel ferrite nanoparticles/PLA composites.

PubMed

Yin, Hong; Chow, Gan-Moog

2009-11-01

Nickel ferrite nanoparticles with or without oleic acid surface coating were mixed with poly(D,L-lactide) (PLA) by double emulsion method. If the nanoparticles were prepared without oleic acid coating, they adsorbed on the PLA surface. If the nanoparticles were coated with oleic acid, they could be readily encapsulated within the PLA microspheres. A slight depression in glass transition temperature was found in all composites and it could be related to the interfacial energies between nanoparticles and PLA. Optimum mixed composite was achieved by reducing interfacial energy. However, loading capacity was limited in this composite. Increasing the amount of nickel ferrite nanoparticles was not useful to increase loading capacity. Cytotoxicity of the composite decreased significantly when nickel ferrite nanoparticles were effectively encapsulated in PLA microspheres. (c) 2008 Wiley Periodicals, Inc.

Composition of single-step media used for human embryo culture.

PubMed

Morbeck, Dean E; Baumann, Nikola A; Oglesbee, Devin

2017-04-01

To determine compositions of commercial single-step culture media and test with a murine model whether differences in composition are biologically relevant. Experimental laboratory study. University-based laboratory. Inbred female mice were superovulated and mated with outbred male mice. Amino acid, organic acid, and ions content were determined for single-step culture media: CSC, Global, G-TL, and 1-Step. To determine whether differences in composition of these media are biologically relevant, mouse one-cell embryos were cultured for 96 hours in each culture media at 5% and 20% oxygen in a time-lapse incubator. Compositions of four culture media were analyzed for concentrations of 30 amino acids, organic acids, and ions. Blastocysts at 96 hours of culture and cell cycle timings were calculated, and experiments were repeated in triplicate. Of the more than 30 analytes, concentrations of glucose, lactate, pyruvate, amino acids, phosphate, calcium, and magnesium varied in concentrations. Mouse embryos were differentially affected by oxygen in G-TL and 1-Step. Four single-step culture media have compositions that vary notably in pyruvate, lactate, and amino acids. Blastocyst development was affected by culture media and its interaction with oxygen concentration. Copyright © 2017 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

[Biomass composition of thermotolerant yeasts of the genus Candida under elevated cultivation temperatures].

PubMed

Chistiakova, T I; Dediukhina, E G; Eroshin, V K

1981-01-01

The effect of growth temperature on the content of nucleic acids, the content and composition of protein, and the pool of free amino acids and lipids was studied under the conditions of chemostat cultivation of yeast strains at constant flow rates and pO2. The pool of free amino acids in all of the strains decreased with an increase in the temperature of growth. Changes in the content and composition of other cellular components depending on temperature were determined by individual characteristics of the strains. A linear relationship between the content of biomass components and the temperature of growth was found only in Candida scottii. The temperature of yeast cultivation may be used as a factor regulating the pool of free intracellular amino acids and the fatty acids composition of lipids.

Dentin remineralization in acid challenge environment via PAMAM and calcium phosphate composite.

PubMed

Liang, Kunneng; Weir, Michael D; Xie, Xianju; Wang, Lin; Reynolds, Mark A; Li, Jiyao; Xu, Hockin H K

2016-11-01

The objective of this study was to investigate the effects of poly (amido amine) (PAMAM), composite with nanoparticles of amorphous calcium phosphate (NACP), and the combined PAMAM+NACP nanocomposite treatment, on remineralization of demineralized dentin in a cyclic artificial saliva/lactic acid environment for the first time. Dentin specimens were prepared and demineralized with 37% phosphoric acid for 15s. Four groups were prepared: (1) dentin control, (2) dentin coated with PAMAM, (3) dentin with NACP composite, (4) dentin with PAMAM+NACP. Specimens were treated with a cyclic artificial saliva/lactic acid regimen for 21days. Acid neutralization and calcium (Ca) and phosphate (P) ion concentrations were measured. The remineralized dentin specimens were examined by scanning electron microscopy (SEM) and hardness testing. NACP nanocomposite had mechanical properties similar to commercial control composites (p>0.1). NACP composite had acid-neutralization and Ca and P ion release capability. PAMAM or NACP composite each alone achieved remineralization and increased the hardness of demineralized dentin (p<0.05). PAMAM+NACP nanocomposite achieved the greatest mineral regeneration in demineralized dentin and the greatest hardness increase in demineralized dentin, which approached the hardness of healthy dentin (p>0.1). The superior remineralization efficacy of PAMAM+NACP was demonstrated for the first time. PAMAM+NACP induced remineralization in demineralized dentin in an acid challenge environment, when conventional remineralization methods such as PAMAM did not work well. The novel PAMAM+NACP composite approach is promising for a wide range of dental applications to inhibit caries and protect tooth structures. Copyright © 2016 The Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

First study of correlation between oleic acid content and SAD gene polymorphism in olive oil samples through statistical and bayesian modeling analyses.

PubMed

Ben Ayed, Rayda; Ennouri, Karim; Ercişli, Sezai; Ben Hlima, Hajer; Hanana, Mohsen; Smaoui, Slim; Rebai, Ahmed; Moreau, Fabienne

2018-04-10

Virgin olive oil is appreciated for its particular aroma and taste and is recognized worldwide for its nutritional value and health benefits. The olive oil contains a vast range of healthy compounds such as monounsaturated free fatty acids, especially, oleic acid. The SAD.1 polymorphism localized in the Stearoyl-acyl carrier protein desaturase gene (SAD) was genotyped and showed that it is associated with the oleic acid composition of olive oil samples. However, the effect of polymorphisms in fatty acid-related genes on olive oil monounsaturated and saturated fatty acids distribution in the Tunisian olive oil varieties is not understood. Seventeen Tunisian olive-tree varieties were selected for fatty acid content analysis by gas chromatography. The association of SAD.1 genotypes with the fatty acids composition was studied by statistical and Bayesian modeling analyses. Fatty acid content analysis showed interestingly that some Tunisian virgin olive oil varieties could be classified as a functional food and nutraceuticals due to their particular richness in oleic acid. In fact, the TT-SAD.1 genotype was found to be associated with a higher proportion of mono-unsaturated fatty acids (MUFA), mainly oleic acid (C18:1) (r = - 0.79, p < 0.000) as well as lower proportion of palmitic acid (C16:0) (r = 0.51, p = 0.037), making varieties with this genotype (i.e. Zarrazi and Tounsi) producing more monounsaturated oleic acid (C18: 1) than saturated acid. These varieties could be thus used as nutraceuticals and functional food. The SAD.1 association with the oleic acid composition of olive oil was identified among the studied varieties. This correlation fluctuated between studied varieties, which might elucidate variability in lipidic composition among them and therefore reflecting genetic diversity through differences in gene expression and biochemical pathways. SAD locus would represent an excellent marker for identifying interesting amongst virgin olive oil lipidic composition.

Soil amino acid composition across a boreal forest successional sequence

Treesearch

Nancy R. Werdin-Pfisterer; Knut Kielland; Richard D. Boone

2009-01-01

Soil amino acids are important sources of organic nitrogen for plant nutrition, yet few studies have examined which amino acids are most prevalent in the soil. In this study, we examined the composition, concentration, and seasonal patterns of soil amino acids across a primary successional sequence encompassing a natural gradient of plant productivity and soil...

Methods for making nucleotide probes for sequencing and synthesis

DOEpatents

Church, George M; Zhang, Kun; Chou, Joseph

2014-07-08

Compositions and methods for making a plurality of probes for analyzing a plurality of nucleic acid samples are provided. Compositions and methods for analyzing a plurality of nucleic acid samples to obtain sequence information in each nucleic acid sample are also provided.

Effect of single flame retardant aluminum tri-hydroxide and boric acid against inflammability and biodegradability of recycled PP/KF composites

NASA Astrophysics Data System (ADS)

Suharty, Neng Sri; Dihardjo, Kuncoro; Handayani, Desi Suci; Firdaus, Maulidan

2016-03-01

Composites rPP/DVB/AA/KF had been reactively synthesized in melt using starting material: recycled polypropylene (rPP), kenaf fiber (KF), multifunctional compound acrylic acid (AA), compatibilizer divinyl benzene (DVB). To improve the inflammability of composites, single flame retardant aluminum tri-hydroxide (ATH) and boric acid (BA) as an additive was added. The inflammability of the composites was tested according to ASTM D635. By using 20% ATH and 5% BA additive in the composites it is effectively inhibiting its time to ignition (TTI). Its burning rate (BR) can be reduced and its heat realease (%HR) decreases. The biodegradability of composites was quantified by its losing weight (LW) of composites after buried for 4 months in the media with rich cellulolytic bacteria. The result shows that the LW of composites in the presence 20% ATH and 5% BA is 6.3%.

Lipomobilization in periparturient dairy cows influences the composition of plasma nonesterified fatty acids and leukocyte phospholipid fatty acids.

PubMed

Contreras, G A; O'Boyle, N J; Herdt, T H; Sordillo, L M

2010-06-01

The periparturient period is characterized by sudden changes in metabolic and immune cell functions that predispose dairy cows to increased incidence of disease. Metabolic changes include alterations in the energy balance that lead to increased lipomobilization with consequent elevation of plasma nonesterified fatty acids (NEFA) concentrations. The objective of this study was to establish the influence of lipomobilization on fatty acid profiles within plasma lipid fractions and leukocyte phospholipid composition. Blood samples from 10 dairy cows were collected at 14 and 7 d before due date, at calving, and at 7, 14, and 30 d after calving. Total lipids and lipid fractions were extracted from plasma and peripheral blood mononuclear cells. The degree of lipomobilization was characterized by measurement of plasma NEFA concentrations. The fatty acid profile of plasma NEFA, plasma phospholipids, and leukocyte phospholipids differed from the composition of total lipids in plasma, where linoleic acid was the most common fatty acid. Around parturition and during early lactation, the proportion of palmitic acid significantly increased in the plasma NEFA and phospholipid fractions with a concomitant increase in the phospholipid fatty acid profile of leukocytes. In contrast, the phospholipid fraction of long-chain polyunsaturated fatty acids in leukocytes was diminished during the periparturient period, especially during the first 2 wk following parturition. This study showed that the composition of total plasma lipids does not necessarily reflect the NEFA and phospholipid fractions in periparturient dairy cows. These findings are significant because it is the plasma phospholipid fraction that contributes to fatty acid composition of membrane phospholipids. Increased availability of certain saturated fatty acids in the NEFA phospholipid fractions may contribute to altered leukocyte functions during the periparturient period. 2010 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Production and transformation of dissolved neutral sugars and amino acids by bacteria in seawater

NASA Astrophysics Data System (ADS)

Jørgensen, L.; Lechtenfeld, O. J.; Benner, R.; Middelboe, M.; Stedmon, C. A.

2014-10-01

Dissolved organic matter (DOM) in the ocean consists of a heterogeneous mixture of molecules, most of which are of unknown origin. Neutral sugars and amino acids are among the few recognizable biomolecules in DOM, and the molecular composition of these biomolecules is shaped primarily by biological production and degradation processes. This study provides insight into the bioavailability of biomolecules as well as the chemical composition of DOM produced by bacteria. The molecular compositions of combined neutral sugars and amino acids were investigated in DOM produced by bacteria and in DOM remaining after 32 days of bacterial degradation. Results from bioassay incubations with natural seawater (sampled from water masses originating from the surface waters of the Arctic Ocean and the North Atlantic Ocean) and artificial seawater indicate that the molecular compositions following bacterial degradation are not strongly influenced by the initial substrate or bacterial community. The molecular composition of neutral sugars released by bacteria was characterized by a high glucose content (47 mol %) and heterogeneous contributions from other neutral sugars (3-14 mol %). DOM remaining after bacterial degradation was characterized by a high galactose content (33 mol %), followed by glucose (22 mol %) and the remaining neutral sugars (7-11 mol %). The ratio of D-amino acids to L-amino acids increased during the experiments as a response to bacterial degradation, and after 32 days, the D/L ratios of aspartic acid, glutamic acid, serine and alanine reached around 0.79, 0.32, 0.30 and 0.51 in all treatments, respectively. The striking similarity in neutral sugar and amino acid compositions between natural (representing marine semi-labile and refractory DOM) and artificial (representing bacterially produced DOM) seawater samples, suggests that microbes transform bioavailable neutral sugars and amino acids into a common, more persistent form.

Prediction of the true digestible amino acid contents from the chemical composition of sorghum grain for poultry.

PubMed

Ebadi, M R; Sedghi, M; Golian, A; Ahmadi, H

2011-10-01

Accurate knowledge of true digestible amino acid (TDAA) contents of feedstuffs is necessary to accurately formulate poultry diets for profitable production. Several experimental approaches that are highly expensive and time consuming have been used to determine available amino acids. Prediction of the nutritive value of a feed ingredient from its chemical composition via regression methodology has been attempted for many years. The artificial neural network (ANN) model is a powerful method that may describe the relationship between digestible amino acid contents and chemical composition. Therefore, multiple linear regressions (MLR) and ANN models were developed for predicting the TDAA contents of sorghum grain based on chemical composition. A precision-fed assay trial using cecectomized roosters was performed to determine the TDAA contents in 48 sorghum samples from 12 sorghum varieties differing in chemical composition. The input variables for both MLR and ANN models were CP, ash, crude fiber, ether extract, and total phenols whereas the output variable was each individual TDAA for every sample. The results of this study revealed that it is possible to satisfactorily estimate the TDAA of sorghum grain through its chemical composition. The chemical composition of sorghum grain seems to highly influence the TDAA contents when considering components such as CP, crude fiber, ether extract, ash and total phenols. It is also possible to estimate the TDAA contents through multiple regression equations with reasonable accuracy depending on composition. However, a more satisfactory prediction may be achieved via ANN for all amino acids. The R(2) values for the ANN model corresponding to testing and training parameters showed a higher accuracy of prediction than equations established by the MLR method. In addition, the current data confirmed that chemical composition, often considered in total amino acid prediction, could be also a useful predictor of true digestible values of selected amino acids for poultry.

Experimental Investigation and Analysis of Mercerized and Citric Acid Surface Treated Bamboo Fiber Reinforced Composite

NASA Astrophysics Data System (ADS)

De, Jyotiraman; Baxi, R. N., Dr.

2017-08-01

Mercerization or NaOH fiber surface treatment is one of the most popular surface treatment processes to make the natural fibers such as bamboo fibers compatible for use as reinforcing material in composites. But NaOH being a chemical is hazardous and polluting to the nature. This paper explores the possibility of use of naturally derived citric acid for bamboo fiber surface treatment and its comparison with NaOH treated Bamboo Fiber Composites. Untreated, 2.5 wt% NaOH treated and 5 wt% citric acid treated Bamboo Fiber Composites with 5 wt% fiber content were developed by Hand Lay process. Bamboo mats made of bamboo slivers were used as reinforcing material. Mechanical and physical characterization was done to compare the effects of NaOH and citric acid bamboo fiber surface treatment on mechanical and physical properties of Bamboo Fiber Composite. The experiment data reveals that the tensile and flexural strength was found to be highest for citric acid and NaOH treated Bamboo Fiber Composite respectively. Water absorption tendency was found more than the NaOH treated Bamboo Fiber Composites. SEM micrographs used to analyze the morphology of fracture surface of tensile test specimens confirm improvement in fiber-matrix interface bonding due to surface treatment of bamboo fibers.

Fatty acid composition of Euphausia superba, Thysanoessa macrura and Euphausia crystallorophias collected from Prydz Bay, Antarctica

NASA Astrophysics Data System (ADS)

Yang, Guang; Li, Chaolun; Wang, Yanqing

2016-04-01

The information of trophic relationship is important for studying the Southern Ocean ecosystems. In this study, three dominant krill species, Euphausia superba, Thysanoessa macrura and Euphausia crystallorophias, were collected from Prydz Bay, Antarctica, during austral summer of 2009/2010. The composition of fatty acids in these species was studied. E. superba and T. macrura showed a similar fatty acid composition which was dominated by C14:0, C16:0, EPA (eicosapentenoic acid) and DHA (decosahexenoic acid) while E. crystallorophias showed higher contents of C18:1(n-9), C18:1(n-7), DHA and EPA than the former two. Higher fatty acid ratios of C18:1(n-9)/18:1(n-7), PUFA (polyunsaturated fatty acid)/SFA (saturated fatty acid), and 18PUFA/16PUFA indicated that E. crystallorophias should be classified as a typical omnivore with a higher trophic position compared with E. superba and T. macrura.

Study of variability in antioxidant composition and fatty acids profile of Longissimus dorsi and Serratus ventralis muscles from Iberian pigs reared in two different Montanera seasons.

PubMed

Tejerina, D; García-Torres, S; de Vaca, M Cabeza; Vázquez, F M; Cava, R

2012-02-01

This investigation was designed to evaluate the effects of variations in antioxidant and fatty acids composition of acorns and grass from two Montanera (free-range system and feeding based on acorns and grass) seasons (2006/07 and 2007/08) on the antioxidant composition and fatty acids profile of m. Longissimus dorsi (LD) and m. Serratus ventralis (SV) from Iberian pigs reared under these Montanera seasons. Acorn and grass composition was affected by Montanera season and consequently, LD and SV muscles showed different contents of α-tocopherol, total phenols, hydrophilic and lipophilic antioxidant activity and fatty acid profile, according with the composition of acorns and grass ingested. Results suggest a lack of uniformity in meat quality between different seasons. This could be due to the variable nature of extensive pig production as reflected in the variability in the composition of the diet (acorns and grass). Copyright © 2011 Elsevier Ltd. All rights reserved.

Intercalation of acrylic acid and sodium acrylate into kaolinite and their in situ polymerization

NASA Astrophysics Data System (ADS)

Zhang, Bo; Li, Yanfeng; Pan, Xiaobing; Jia, Xin; Wang, Xiaolong

2007-02-01

Novel nano-composites of poly (acrylic acid)-kaolinite were prepared, and intercalation and in situ polymerization were used in this process. The nano-composites were obtained by in situ polymerization of acrylic acid (AA) and sodium acrylate (AANa) intercalated into organo-kaolinite, which was obtained by refining and chemically modifying with solution intercalation step in order to increase the basal plane distance of the original clay. The modification was completed by using dimethyl-sulfoxide (DMSO)/methanol and potassium acetate (KAc)/water systems step by step. The materials were characterized with the help of XRD, FT-IR and TEM; the results confirmed that poly(acrylic acid) (PAA) and poly(sodium acrylate) (PAANa) were intercalated into the interlamellar spaces of kaolinite, the resulting copolymer composites (CC0 : copolymer crude kaolinite composite, CC1 : copolymer DMSO kaolinite composite, CC2 : copolymer KAc kaolinite composite) of CC2 exhibited a lamellar nano-composite with a mixed nano-morphology, and partial exfoliation of the intercalating clay platelets should be the main morphology. Finally, the effect of neutralization degree on the intercalation behavior was also investigated.

Changes in properties of polyacid-modified composite resins (compomers) following storage in acidic solutions.

PubMed

Nicholson, J W; Gjorgievska, E; Bajraktarova, B; McKenzie, M A

2003-06-01

The interaction of three polyacid-modified composite resins (compomers) with various acidic storage solutions, and also water, over periods of time up to 6 months has been studied and compared with those of a glass-ionomer and a composite resin. This interaction has been shown to vary in a complex way with length of storage and nature of the acid, and citric acid was found to be the most aggressive storage medium for glass-ionomer cement, and also for the compomers. The pure composite resin, by contrast, was relatively unaffected by all of the acid solutions examined. In all acids, the compomers showed a distinct buffering effect, i.e. they increased the pH towards neutral, as did the glass-ionomer. The extent of this also varied with duration of storage and nature of the acid. The biaxial flexure strength was determined and found to be essentially unaffected by the complex chemical interactions with acidic storage solutions. Values obtained for the compomers were lower than those of the composite resin, but above those of the glass-ionomer. Fourier-transform infrared (FT-IR) spectroscopy was employed to study the changes in the compomers following storage in the aqueous media, but bands were broad and no detailed assignments could be made. There were changes in the region of the spectra associated with metal carboxylates however, and this indicates that the secondary acid-base reaction had occurred following water uptake.

Perfluoroalkyl acid contamination and polyunsaturated fatty acid composition of French freshwater and marine fishes.

PubMed

Yamada, Ami; Bemrah, Nawel; Veyrand, Bruno; Pollono, Charles; Merlo, Mathilde; Desvignes, Virginie; Sirot, Véronique; Oseredczuk, Marine; Marchand, Philippe; Cariou, Ronan; Antignac, Jean-Phillippe; Le Bizec, Bruno; Leblanc, Jean-Charles

2014-07-30

In this study, French marine and freshwater fish perfluoroalkyl acid (PFAA) contamination are presented along with their fatty acid (FA) composition to provide further elements for a risk/benefit balance of fish consumption to be assessed. The 29 most consumed marine fish species were collected in four metropolitan French coastal areas in 2004 to constitute composite samples. Geographical differences in terms of consumed species and contamination level were taken into account. Three hundred and eighty-seven composite samples corresponding to 16 freshwater fish species collected between 2008 and 2010 in the six major French rivers or their tributaries were selected among the French national agency for water and aquatic environments freshwater fish sample library. The raw edible parts were analyzed for FA composition and PFAA contamination. Results show that freshwater fishes are more contaminated by PFAAs than marine fishes and do not share the same contamination profile. Freshwater fish contamination is mostly driven by perfluorooctane sulfonate (PFOS) (75%), whereas marine fish contamination is split between perfluorooctanoic acid (PFOA) (24%), PFOS (20%), perfluorohexanoic acid (PFHxA) (15%), perfluoropentanoic acid (PFHpA) (11%), and perfluorobutanoic acid (PFBA) (11%). Common carp, pike-perch, European perch, thicklip grey mullet, and common roach presented the most unfavorable balance profile due to their high level of PFAAs and low level of n-3 long-chain polyunsaturated fatty acids (LC-PUFAs). These data could be used, if needed, in an updated opinion on fish consumption that takes into account PFAA contamination.

Influence of Lipid Composition in Amplifying or Ameliorating Toxicant Effects on Phytoplankton.

DTIC Science & Technology

1992-04-30

since they often have a high lipid content and high concentrations of eicosapentaenoic acid (Sicko-Goad et al. 1988; Volkman et al. 1989; Ahlgren et al...in percent composition of total saturated and unsaturated fatty acids with respect to sampling period in the light/dark cycle .................. A2-3...diatom species ................ A1-4 A2 1 Fatty acid identification and percent composition with standard errors of all Cyclotella meneghiniana

Dietary fat and the diabetic state alter insulin binding and the fatty acyl composition of the adipocyte plasma membrane.

PubMed Central

Field, C J; Ryan, E A; Thomson, A B; Clandinin, M T

1988-01-01

Control and diabetic rats were fed on semi-purified high-fat diets providing a polyunsaturated/saturated fatty acid ratio (P/S) of 1.0 or 0.25, to examine the effect of diet on the fatty acid composition of major phospholipids of the adipocyte plasma membrane. Feeding the high-P/S diet (P/S = 1.0) compared with the low-P/S diet (P/S = 0.25) increased the content of polyunsaturated fatty acids in membrane phospholipids in both control and diabetic animals. The diabetic state decreased the content of polyunsaturated fatty acids, particularly arachidonic acid, in adipocyte membrane phospholipids. The decrease in arachidonic acid in membrane phospholipids of diabetic animals tended to be normalized to within the control values when high-P/S diets were given. For control animals, altered plasma-membrane composition was associated with change in insulin binding, suggesting that change in plasma-membrane composition may have physiological consequences for insulin-stimulated functions in the adipocyte. PMID:3052424

Composition of precipitation in remote areas of the world

DOE Office of Scientific and Technical Information (OSTI.GOV)

Galloway, J.N.; Likens, G.E.; Keene, W.C.

1982-10-20

The Global Precipitation Chemistry Project collects precipitation by event to determine composition and processes controlling it in five remote areas. Compositions (excluding seasalt) at St. Georges, Bermuda, were primarily controlled by anthropogenic processes; compositions and acidities at San Carlos, Venezuela, Katherine, Australia, Poker, Flat, Alaska, and Amsterdam Island were controlled by unknown mixtures of natural or anthropogenic processes. Precipitation was acidic; average volume-weighted pH values were 4.8 for Bermuda; 5.0, Alaska; 4.9, Amsterdam Island; 4.8, Australia; 4.8, Venezuela. Acidities at Bermuda and Alaska were from long-range transport of sulfate aerosol; at Venezuela, Australia, and Amsterdam Island, from mixtures of weakmore » organic and strong mineral acids, primarily H/sub 2/SO/sub 4/. Relative proportions of weak to strong acids were largest at Venezuela and lowest at Amsterdam Island. Weak and strong acids were from mixtures of natural and anthropogenic processes. Once contributions from human activities were removed, the lower limit of natural contributions was probably > or =pH 5.« less

Frying stability of high oleic sunflower oils as affected by composition of tocopherol isomers and linoleic acid content.

PubMed

Aladedunye, Felix; Przybylski, Roman

2013-12-01

The influence of linoleic acid content and tocopherol isomeric composition on the frying performance of high oleic sunflower oil was evaluated during a 14-day restaurant style frying operation. At equal linoleic acid content, no significant difference was observed between high oleic sunflower oil containing only α-tocopherol and the sample containing a mixture of α-, γ-, and δ-isomers as measured by the amount of total polar components, oligomers, anisidine value, and free fatty acids. On the contrary, at similar tocopherol isomeric composition, high oleic sunflower oil containing lower amount of linoleic acid showed superior frying stability compared to the sample with a higher content of linoleic acid, suggesting that the frying performance of high oleic sunflower oil is dictated primarily by the level of linoleic acid, with the tocopherol isomeric composition of the oil having no significant influence. In all oil samples, the loss of γ-tocopherol was higher than the corresponding loss of α-tocopherol. Copyright © 2013 Elsevier Ltd. All rights reserved.

Elicitor and nitrogen applications to Garnacha, Graciano and Tempranillo vines: effect on grape amino acid composition.

PubMed

Gutiérrez-Gamboa, Gastón; Portu, Javier; López, Rosa; Santamaría, Pilar; Garde-Cerdán, Teresa

2018-04-01

Elicitors and nitrogen foliar applications to vineyards could regulate grape nitrogen composition, which has an important effect on grape and wine quality. Thus the aim of this research was to study the effect of foliar elicitor treatments, methyl jasmonate (MeJ) and yeast extract (YE), and foliar nitrogen applications, urea (Ur) and phenylalanine (Phe), to Garnacha, Graciano and Tempranillo vines on grape amino acid composition. The results showed that elicitor and nitrogen foliar applications to Garnacha and Tempranillo grapevines decreased the must amino acid concentration. However, Phe application to these two grapevines increased the must Phe content. The treatments applied to Graciano grapevines barely effected the grape amino acid content. According to the percentage of variance attributable, the variety had a higher impact on the must amino acid composition than the treatments and their interaction, except in certain amino acids such as Phe. The influence of elicitor and nitrogen foliar applications to grapevines on grape amino acid concentration was strongly conditioned by the variety. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Cd(II) Sorption on Montmorillonite-Humic acid-Bacteria Composites

PubMed Central

Du, Huihui; Chen, Wenli; Cai, Peng; Rong, Xingmin; Dai, Ke; Peacock, Caroline L.; Huang, Qiaoyun

2016-01-01

Soil components (e.g., clays, bacteria and humic substances) are known to produce mineral-organic composites in natural systems. Herein, batch sorption isotherms, isothermal titration calorimetry (ITC), and Cd K-edge EXAFS spectroscopy were applied to investigate the binding characteristics of Cd on montmorillonite(Mont)-humic acid(HA)-bacteria composites. Additive sorption and non-additive Cd(II) sorption behaviour is observed for the binary Mont-bacteria and ternary Mont-HA-bacteria composite, respectively. Specifically, in the ternary composite, the coexistence of HA and bacteria inhibits Cd adsorption, suggesting a “blocking effect” between humic acid and bacterial cells. Large positive entropies (68.1 ~ 114.4 J/mol/K), and linear combination fitting of the EXAFS spectra for Cd adsorbed onto Mont-bacteria and Mont-HA-bacteria composites, demonstrate that Cd is mostly bound to bacterial surface functional groups by forming inner-sphere complexes. All our results together support the assertion that there is a degree of site masking in the ternary clay mineral-humic acid-bacteria composite. Because of this, in the ternary composite, Cd preferentially binds to the higher affinity components-i.e., the bacteria. PMID:26792640

Detailed Dimethylacetal and Fatty Acid Composition of Rumen Content from Lambs Fed Lucerne or Concentrate Supplemented with Soybean Oil

PubMed Central

Alves, Susana P.; Santos-Silva, José; Cabrita, Ana R. J.; Fonseca, António J. M.; Bessa, Rui J. B.

2013-01-01

Lipid metabolism in the rumen is responsible for the complex fatty acid profile of rumen outflow compared with the dietary fatty acid composition, contributing to the lipid profile of ruminant products. A method for the detailed dimethylacetal and fatty acid analysis of rumen contents was developed and applied to rumen content collected from lambs fed lucerne or concentrate based diets supplemented with soybean oil. The methodological approach developed consisted on a basic/acid direct transesterification followed by thin-layer chromatography to isolate fatty acid methyl esters from dimethylacetal, oxo- fatty acid and fatty acid dimethylesters. The dimethylacetal composition was quite similar to the fatty acid composition, presenting even-, odd- and branched-chain structures. Total and individual odd- and branched-chain dimethylacetals were mostly affected by basal diet. The presence of 18∶1 dimethylacetals indicates that biohydrogenation intermediates might be incorporated in structural microbial lipids. Moreover, medium-chain fatty acid dimethylesters were identified for the first time in the rumen content despite their concentration being relatively low. The fatty acids containing 18 carbon-chain lengths comprise the majority of the fatty acids present in the rumen content, most of them being biohydrogenation intermediates of 18∶2n−6 and 18∶3n−3. Additionally, three oxo- fatty acids were identified in rumen samples, and 16-O-18∶0 might be produced during biohydrogenation of the 18∶3n−3. PMID:23484024

Correlating Mineralogy and Amino Acid Contents of Milligram-Scale Murchison Carbonaceous Chondrite Samples

NASA Technical Reports Server (NTRS)

Burton, Aaron, S.; Berger, Eve L.; Locke, Darren R.; Elsila, Jamie E.; Glavin, Daniel P.; Dworkin, Jason P.

2015-01-01

Amino acids, the building blocks of proteins, have been found to be indigenous in most of the carbonaceous chondrite groups. The abundances of amino acids, as well as their structural, enantiomeric and isotopic compositions differ significantly among meteorites of different groups and petrologic types. This suggests that there is a link between parent-body conditions, mineralogy and the synthesis and preservation of amino acids (and likely other organic molecules). However, elucidating specific causes for the observed differences in amino acid composition has proven extremely challenging because samples analyzed for amino acids are typically much larger ((is) approximately 100 mg powders) than the scale at which meteorite heterogeneity is observed (sub mm-scale differences, (is) approximately 1-mg or smaller samples). Thus, the effects of differences in mineralogy on amino acid abundances could not be easily discerned. Recent advances in the sensitivity of instrumentation have made possible the analysis of smaller samples for amino acids, enabling a new approach to investigate the link between mineralogical con-text and amino acid compositions/abundances in meteorites. Through coordinated mineral separation, mineral characterization and highly sensitive amino acid analyses, we have performed preliminary investigations into the relationship between meteorite mineralogy and amino acid composition. By linking amino acid data to mineralogy, we have started to identify amino acid-bearing mineral phases in different carbonaceous meteorites. The methodology and results of analyses performed on the Murchison meteorite are presented here.

Chemical composition of seeds and oil of Xylopia aethiopica grown in Nigeria.

PubMed

Barminas, J T; James, M K; Abubakar, U M

1999-01-01

The chemical composition and mineral constituents of Xylopia aethiopica, which is valued as a spice in Nigeria, were determined along with the physicochemical characteristics of the seed oil. The seeds had the following chemical compositions moisture (8.43 g/100 g), ash (5.89 g/100 g), crude lipid (9.58 g/100 g), crude protein (12.45 g/100 g) crude fiber (8.66 g/100 g) and carbohydrate (63.65 g/100 g). Calcium and potassium were the major minerals in the seed. The extracted lipid was examined for fatty acid composition. Linoleic (45.1 g/100 g) and oleic (26.5 g/100 g) acids were the predominant unsaturated fatty acids, while palmitic acid (18.0 g/100 g) was the major saturated acid. The iodine value of 97 g/100 g indicates that the seed oil is a non-drying type.

Trans-fatty acids in cooking oils in Bogota, Colombia: changes in the food supply from 2008 to 2013.

PubMed

Moynihan, Meghan; Villamor, Eduardo; Marin, Constanza; Mora-Plazas, Mercedes; Campos, Hannia; Baylin, Ana

2015-12-01

Long-chain n-3 fatty acid intake in Colombia is low because fish consumption is limited. Vegetable oils with high n-3 fatty acid content are recommended, but their concentrations of trans fats were high in previous studies. Thus, regular monitoring of the fatty acid composition of vegetable oils is required. Our objective was to quantify the fatty acid composition in commercially available oils in Bogota, Colombia and determine if composition changed from 2008 to 2013. Cross-sectional study. We obtained samples of all commercially available oils reported in a survey of low- and middle-income families with a child participating in the Bogota School Children Cohort. Bogota, Colombia. Not applicable. Sunflower oil had the highest trans-fatty acid content (2.18%). Canola oil had the lowest proportion of trans-fatty acids (0.40%) and the highest n-3 fatty acid content (9.37%). In terms of percentage reduction from 2008 to 2013 in 18:1 and 18:2 trans-fatty acids, canola oil had 89% and 65% reduction, mixed oils had 44% and 48% reduction, and sunflower oil had 25% and 51 % reduction, respectively. Soyabean oil became widely available in 2013. The content of trans-fatty acids decreased in all oils from 2008 to 2013, suggesting a voluntary reduction by industry. We believe that regular monitoring of the fatty acid composition of oils is warranted.

Effect of bioglass 45S5 addition on properties, microstructure and cellular response of tetracalcium phosphate/monetite cements

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stulajterova, R., E-mail: rstulajterova@saske.sk

Tetracalcium phosphate/nanomonetite (TTCPMH) cement composites with 7.5 and 15 wt% addition of melt-derived 45S5 bioactive glass were prepared by mechanical homogenization of powder components and 2% NaH{sub 2}PO{sub 4} solution was used as a hardening liquid. The properties of composites with the acidic (Ca/P ratio equal 1.5) or basic (Ca/P ratio equal 1.67) TTCPMH component were compared. Addition of glass component caused rapid rise in pH of composites up to 10. In microstructure of basic cement composite, the large bioglass particles weakly bounded to surrounding cement matrix were found contrary to a more compact microstructure of acidic cement composites withmore » the high number of spherical silica particles. Both the significant refinement of hydroxyapatite particles and the change to needle-like morphology with rise in the content of bioglass were identified in hydroxyapatite coatings created during soaking of composites in phosphate buffered saline. In acidic cement mixtures, the increase of compressive strength with an amount of bioglass was found whereas the opposite tendency was revealed in the case of basic cement mixtures. The higher concentrations of ions were verified in solutions after immersion of acidic cement composites. The severe cytotoxicity of extracts and composite cement substrates containing 15 wt% of bioglass demonstrated adverse effects of both the ionic concentrations and unappropriate surface texture on proliferation of mesenchymal stem cells. The enhanced ALP activities of cells cultured on composite cements confirmed the positive effect of bioactive glass addition on differentiation of mesenchymal stem cells. - Highlights: • Novel B45S5 bioglass/tetracalcium phosphate/nanomonetite cement composites • Cement basicity negatively affected their microstructure. • Acid composite cements had higher compressive strengths than basic composites. • Fast differentiation of MSC to osteoblast line on composite with 7.5 wt% of bioglass • Severe cytotoxicity of 24 h extracts from composites with 15 wt% of bioglass.« less

Erythrocyte Membrane Fatty Acid Composition in Premenopausal Patients with Iron Deficiency Anemia.

PubMed

Aktas, Mehmet; Elmastas, Mahfuz; Ozcicek, Fatih; Yilmaz, Necmettin

2016-01-01

Iron deficiency anemia (IDA) is one of the most common nutritional disorders in the world. In the present study, we evaluated erythrocyte membrane fatty acid composition in premenopausal patients with IDA. Blood samples of 102 premenopausal women and 88 healthy control subjects were collected. After the erythrocytes were separated from the blood samples, the membrane lipids were carefully extracted, and the various membrane fatty acids were measured by gas chromatography (GC). Statistical analyses were performed with the SPSS software program. We used blood ferritin concentration <15 ng/mL as cut-off for the diagnosis of IDA. The five most abundant individual fatty acids obtained were palmitic acid (16:0), oleic acid (18:1, n-9c), linoleic acid (18:2, n-6c), stearic acid (18:0), and erucic acid (C22:1, n-9c). These compounds constituted about 87% of the total membrane fatty acids in patients with IDA, and 79% of the total membrane fatty acids in the control group. Compared with control subjects, case patients had higher percentages of palmitic acid (29.9% case versus 25.3% control), oleic acid (16.8% case versus 15.1% control), and stearic acid (13.5% case versus 10.5% control), and lower percentages of erucic acid (11.5% case versus 13.6% control) and linoleic acid (15.2% case versus 15.4% control) in their erythrocyte membranes. In conclusion, the total-erythrocyte-membrane saturated fatty acid (SFA) composition in premenopausal women with IDA was found to be higher than that in the control group; however, the total-erythrocyte-membrane unsaturated fatty acid (UFA) composition in premenopausal women with IDA was found to be lower than that in the control group. The differences in these values were statistically significant.

Dosimetry Evolution in Teletherapy: Polimer Gel

NASA Astrophysics Data System (ADS)

Hamann, J. H.; Peixoto, J. G. P.

2018-03-01

Polymer gels evolution and chemical composition used in dosimetry. Type Composition First gels Folin’s Phenol or Gallic Acid Polymer Gel Agarose and N,N’-methylene-bis-acrylamide BANANA Bis, acrylamide, nitrous oxide and agarose BANG-1TM Bis, acrylamide, nitrogen and gelatin BANG-2TM Bis, acrylic acid, sodium hydroxide, nitrogen and gelatin BANG-3TM Bis, methacrylate acid, sodium hydroxide, nitrogen and gelatin MAGIC Methacrylate acid, ascorbic acid, gelatin and copper sulphate

Preparation and corrosion resistance of magnesium phytic acid/hydroxyapatite composite coatings on biodegradable AZ31 magnesium alloy.

PubMed

Zhang, Min; Cai, Shu; Zhang, Feiyang; Xu, Guohua; Wang, Fengwu; Yu, Nian; Wu, Xiaodong

2017-06-01

In this work, a magnesium phytic acid/hydroxyapatite composite coating was successfully prepared on AZ31 magnesium alloy substrate by chemical conversion deposition technology with the aim of improving its corrosion resistance and bioactivity. The influence of hydroxyapatite (HA) content on the microstructure and corrosion resistance of the coatings was investigated. The results showed that with the increase of HA content in phytic acid solution, the cracks on the surface of the coatings gradually reduced, which subsequently improved the corrosion resistance of these coated magnesium alloy. Electrochemical measurements in simulated body fluid (SBF) revealed that the composite coating with 45 wt.% HA addition exhibited superior surface integrity and significantly improved corrosion resistance compared with the single phytic acid conversion coating. The results of the immersion test in SBF showed that the composite coating could provide more effective protection for magnesium alloy substrate than that of the single phytic acid coating and showed good bioactivity. Magnesium phytic acid/hydroxyapatite composite, with the desired bioactivity, can be synthesized through chemical conversion deposition technology as protective coatings for surface modification of the biodegradable magnesium alloy implants. The design idea of the new type of biomaterial is belong to the concept of "third generation biomaterial". Corrosion behavior and bioactivity of coated magnesium alloy are the key issues during implantation. In this study, preparation and corrosion behavior of magnesium phytic acid/hydroxyapatite composite coatings on magnesium alloy were studied. The basic findings and significance of this paper are as follows: 1. A novel environmentally friendly, homogenous and crack-free magnesium phytic acid/hydroxyapatite composite coating was fabricated on AZ31 magnesium alloy via chemical conversion deposition technology with the aim of enhancing its corrosion resistance and bioactivity. The chemical conversion coatings, which are formed through the reaction between the substrate and the environment, have attracted increasing attention owing to the relative low treatment temperature, favorable bonding to substrate and simple implementation process. 2. With the increasing of hydroxyapatite (HA) content, the crack width in the composite coatings and the thickness of the coatings exhibit obviously decreased. The reason is probably that when adding HA into the phytic acid solution, the amount of active hydroxyl groups in the phytic acid are reduced via forming the coordination bond between P-OH groups from phytic acid and P-OH groups from the surface of HA, thus decreasing the coating thickness and hydrogen formation, as well as avoiding coating cracking. 3. By adjusting the HA content to 45 wt.%, a dense and relatively smooth composite coating with ~1.4 μm thickness is obtained on magnesium alloy, and exhibits high corrosion resistance and good bioactivity when compared with the single phytic acid conversion coating.

Effect of Exogenous Abscisic Acid and Methyl Jasmonate on Anthocyanin Composition, Fatty Acids, and Volatile Compounds of Cabernet Sauvignon (Vitis vinifera L.) Grape Berries.

PubMed

Ju, Yan-Lun; Liu, Min; Zhao, Hui; Meng, Jiang-Fei; Fang, Yu-Lin

2016-10-12

The anthocyanin composition, fatty acids, and volatile aromas are important for Cabernet Sauvignon grape quality. This study evaluated the effect of exogenous abscisic acid (ABA) and methyl jasmonate (MeJA) on the anthocyanin composition, fatty acids, lipoxygenase activity, and the volatile compounds of Cabernet Sauvignon grape berries. Exogenous ABA and MeJA improved the content of total anthocyanins (TAC) and individual anthocyanins. Lipoxygenase (LOX) activity also increased after treatment. Furthermore, 16 fatty acids were detected. The linoleic acid concentration gradually increased with ABA concentration. The fatty acid content decreased with increasing MeJA concentration and then increased again, with the exception of linoleic acid. After exogenous ABA and MeJA treatment, the C6 aroma content increased significantly. Interestingly, the exogenous ABA and MeJA treatments improved mainly the content of 1-hexanol, hexanal, and 2-heptanol. These results provide insight into the effect of plant hormones on wine grapes, which is useful for grape quality improvement.

Amino Acid compositions of 27 food fishes and their importance in clinical nutrition.

PubMed

Mohanty, Bimal; Mahanty, Arabinda; Ganguly, Satabdi; Sankar, T V; Chakraborty, Kajal; Rangasamy, Anandan; Paul, Baidyanath; Sarma, Debajit; Mathew, Suseela; Asha, Kurukkan Kunnath; Behera, Bijay; Aftabuddin, Md; Debnath, Dipesh; Vijayagopal, P; Sridhar, N; Akhtar, M S; Sahi, Neetu; Mitra, Tandrima; Banerjee, Sudeshna; Paria, Prasenjit; Das, Debajeet; Das, Pushpita; Vijayan, K K; Laxmanan, P T; Sharma, A P

2014-01-01

Proteins and amino acids are important biomolecules which regulate key metabolic pathways and serve as precursors for synthesis of biologically important substances; moreover, amino acids are building blocks of proteins. Fish is an important dietary source of quality animal proteins and amino acids and play important role in human nutrition. In the present investigation, crude protein content and amino acid compositions of important food fishes from different habitats have been studied. Crude protein content was determined by Kjeldahl method and amino acid composition was analyzed by high performance liquid chromatography and information on 27 food fishes was generated. The analysis showed that the cold water species are rich in lysine and aspartic acid, marine fishes in leucine, small indigenous fishes in histidine, and the carps and catfishes in glutamic acid and glycine. The enriched nutrition knowledge base would enhance the utility of fish as a source of quality animal proteins and amino acids and aid in their inclusion in dietary counseling and patient guidance for specific nutritional needs.

Amino Acid Compositions of 27 Food Fishes and Their Importance in Clinical Nutrition

PubMed Central

Mahanty, Arabinda; Sankar, T. V.; Chakraborty, Kajal; Rangasamy, Anandan; Paul, Baidyanath; Sarma, Debajit; Mathew, Suseela; Asha, Kurukkan Kunnath; Behera, Bijay; Aftabuddin, Md.; Debnath, Dipesh; Vijayagopal, P.; Sridhar, N.; Akhtar, M. S.; Sahi, Neetu; Mitra, Tandrima; Banerjee, Sudeshna; Das, Debajeet; Das, Pushpita; Vijayan, K. K.; Laxmanan, P. T.; Sharma, A. P.

2014-01-01

Proteins and amino acids are important biomolecules which regulate key metabolic pathways and serve as precursors for synthesis of biologically important substances; moreover, amino acids are building blocks of proteins. Fish is an important dietary source of quality animal proteins and amino acids and play important role in human nutrition. In the present investigation, crude protein content and amino acid compositions of important food fishes from different habitats have been studied. Crude protein content was determined by Kjeldahl method and amino acid composition was analyzed by high performance liquid chromatography and information on 27 food fishes was generated. The analysis showed that the cold water species are rich in lysine and aspartic acid, marine fishes in leucine, small indigenous fishes in histidine, and the carps and catfishes in glutamic acid and glycine. The enriched nutrition knowledge base would enhance the utility of fish as a source of quality animal proteins and amino acids and aid in their inclusion in dietary counseling and patient guidance for specific nutritional needs. PMID:25379285

Chemical and Nutritional Composition of Terminalia ferdinandiana (Kakadu Plum) Kernels: A Novel Nutrition Source

PubMed Central

Netzel, Michael E.; Tinggi, Ujang

2018-01-01

Terminalia ferdinandiana (Kakadu plum) is a native Australian fruit. Industrial processing of T. ferdinandiana fruits into puree generates seeds as a by-product, which are generally discarded. The aim of our present study was to process the seed to separate the kernel and determine its nutritional composition. The proximate, mineral and fatty acid compositions were analysed in this study. Kernels are composed of 35% fat, while proteins account for 32% dry weight (DW). The energy content and fiber were 2065 kJ/100 g and 21.2% DW, respectively. Furthermore, the study showed that kernels were a very rich source of minerals and trace elements, such as potassium (6693 mg/kg), calcium (5385 mg/kg), iron (61 mg/kg) and zinc (60 mg/kg) DW, and had low levels of heavy metals. The fatty acid composition of the kernels consisted of omega-6 fatty acid, linoleic acid (50.2%), monounsaturated oleic acid (29.3%) and two saturated fatty acids namely palmitic acid (12.0%) and stearic acid (7.2%). The results indicate that T. ferdinandiana kernels have the potential to be utilized as a novel protein source for dietary purposes and non-conventional supply of linoleic, palmitic and oleic acids. PMID:29649154

Determination of the structure of lecithins.

PubMed

Blank, M L; Nutter, L J; Privett, O S

1966-03-01

A method is described for the determination of the classes of lecithins in terms of unsaturated and saturated fatty acids based on a total fatty acid composition, the composition of the fatty acids in the beta-position, and the amount of disaturated class determined via mercuric acetate adduct formation. The accuracy of the method was determined on lecithins of known composition and the method was applied to lecithins isolated from milk serum and egg lipids, safflower and soybean oils.

Genome-Wide Association Study Singles Out SCD and LEPR as the Two Main Loci Influencing Intramuscular Fat Content and Fatty Acid Composition in Duroc Pigs

PubMed Central

Ros-Freixedes, Roger; Gol, Sofia; Pena, Ramona N.; Tor, Marc; Ibáñez-Escriche, Noelia; Dekkers, Jack C. M.; Estany, Joan

2016-01-01

Intramuscular fat (IMF) content and fatty acid composition affect the organoleptic quality and nutritional value of pork. A genome-wide association study was performed on 138 Duroc pigs genotyped with a 60k SNP chip to detect biologically relevant genomic variants influencing fat content and composition. Despite the limited sample size, the genome-wide association study was powerful enough to detect the association between fatty acid composition and a known haplotypic variant in SCD (SSC14) and to reveal an association of IMF and fatty acid composition in the LEPR region (SSC6). The association of LEPR was later validated with an independent set of 853 pigs using a candidate quantitative trait nucleotide. The SCD gene is responsible for the biosynthesis of oleic acid (C18:1) from stearic acid. This locus affected the stearic to oleic desaturation index (C18:1/C18:0), C18:1, and saturated (SFA) and monounsaturated (MUFA) fatty acids content. These effects were consistently detected in gluteus medius, longissimus dorsi, and subcutaneous fat. The association of LEPR with fatty acid composition was detected only in muscle and was, at least in part, a consequence of its effect on IMF content, with increased IMF resulting in more SFA, less polyunsaturated fatty acids (PUFA), and greater SFA/PUFA ratio. Marker substitution effects estimated with a subset of 65 animals were used to predict the genomic estimated breeding values of 70 animals born 7 years later. Although predictions with the whole SNP chip information were in relatively high correlation with observed SFA, MUFA, and C18:1/C18:0 (0.48–0.60), IMF content and composition were in general better predicted by using only SNPs at the SCD and LEPR loci, in which case the correlation between predicted and observed values was in the range of 0.36 to 0.54 for all traits. Results indicate that markers in the SCD and LEPR genes can be useful to select for optimum fatty acid profiles of pork. PMID:27023885

Growth effect on liver fatty acid composition of damselfishes genus Abudefduf collected in coral reef habitats of the Malaysian South China Sea.

PubMed

Arai, Takaomi; Amalina, Razikin; Bachok, Zainudin

2015-01-01

In order to understand feeding ecology, habitat use and migration of coral reef fish, fatty acid composition was examined in damselfish species Abudefduf bengalensis and A. sexfasciatus collected in the Malaysian South China Sea. Proportions of saturated fatty acids (SAFA) ranged from 49.5% to 74.2%, with the highest proportions in fatty acids, the second highest was monounsaturated fatty acids (MUFA) ranged from 21.4% to 47.4% and the proportion of polyunsaturated fatty acids (PUFA) was the lowest ranged from 3.1% to 6.0%. Palmitic acid (16:0) was the most common in SAFA, oleic acid (C18:1ω9c) was the dominant in MUFA and linolenic acid (C18:3n3) showed the highest proportion in PUFA. Fatty acid concentrations, especially in SAFA and MUFA, could be related to physiological condition, sexual development, and recent feeding events. The diet shift revealed by the fatty acid composition suggests changes in habitat use and migration scale in coral reef environment of genus Abudefduf.

Starch/fiber/poly(lactic acid) foam and compressed foam composites

USDA-ARS?s Scientific Manuscript database

Composites of starch, fiber, and poly(lactic acid) (PLA) were made using a foam substrate formed by dehydrating starch or starch/fiber gels. PLA was infiltrated into the dry foam to provide better moisture resistance. Foam composites were compressed into plastics using force ranging from 4-76MPa. Te...

Trophic links and nutritional condition of fish early life stages in a temperate estuary.

PubMed

Primo, Ana Lígia; Correia, Catarina; Marques, Sónia Cotrim; Martinho, Filipe; Leandro, Sérgio; Pardal, Miguel

2018-02-01

The physiological and nutritional condition of fish larvae affect their survival and thus, the success of estuaries as nursery areas. Fatty acid composition has been useful to determine fish nutritional condition, as well as trophic relationships in marine organisms. The present study analyses the fatty acid (FA) composition of fish larvae during spring and summer in the Mondego estuary, Portugal. FA composition, trophic markers (FATM) and fish nutritional condition was analysed for Gobiidae and Sardina pilchardus larvae and the relationships with the local environment evaluated. Results showed that both taxa differed mainly in the stearic acid (C18:0) and eicosapentaenoic acid (EPA) content, with important amounts in Gobiidae and S. pilchardus, respectively. Gobiidae larvae presenting high nutritional condition and omnivore FATM. Fatty acid composition seems to be related with their natural habitat selection and food availability, while fish larvae nutritional condition also showed a strong link with the water temperature and presence of potential predators. This study suggests that FA composition can be a useful tool in assessing planktonic trophic relationships and in identifying species natural habitat. Copyright © 2017. Published by Elsevier Ltd.

Fatty acid composition of seed oil from Fremontodendron californicum

USDA-ARS?s Scientific Manuscript database

The fatty acid composition of the low water-use shrub Fremontodendron californicum was examined by high temperature capillary gas chromatography. The ground seeds were extracted by supercritical fluid extraction (SFE) to obtain the oil (25.6% w/w) and for subsequent determination of the fatty acid c...

Influence of a peracetic acid-based immersion on indirect composite resin.

PubMed

Samuel, Susana Maria Werner; Fracaro, Gisele Baggio; Collares, Fabrício Mezzomo; Leitune, Vicente Castelo Branco; Campregher, Ulisses Bastos

2011-06-01

The aim of this study was to evaluate the influence of immersion in a 0.2% peracetic acid-based disinfectant on the three-point flexural strength, water sorption and water solubility of an indirect composite resin. Specimens were produced according to ISO 4049:2000 specifications and were divided in two groups: Control group, with no disinfection and Disinfected group, with three 10 min immersions in the peracetic acid intercalated with 10 min immersions in sterile distilled water. All evaluations were conducted in compliance with ISO specifications. Three-point flexural strength, water sorption and solubility of indirect composite resin before and after immersion showed no statistical significant differences (p > 0.05) and met ISO standard requirements. Immersion in peracetic acid solution showed no influence in indirect composite resin tested properties.

Chemical composition and antimicrobial activity of fatty acid methyl ester of Quercus leucotrichophora fruits.

PubMed

Sati, Ankita; Sati, Sushil Chandra; Sati, Nitin; Sati, O P

2017-03-01

Natural fats and dietary oils are chief source of fatty acids and are well known to have antimicrobial activities against various microbes. The chemical composition and antimicrobial activities of fatty acids from fruits of white Oak (Quercus leucotrichophora) are yet unexplored and therefore the present study for the first time determines the fatty acid composition, and the antibacterial and antifungal activities of fatty acid methyl esters (FAME) of the white Oak plant found along the Himalayan region of Uttarakhand, India. The GCMS analysis revealed the presence of higher amount of saturated fatty acids than unsaturated fatty acids. FAME extract of fruits of Q. leucotrichophora demonstrated better antibacterial activity against Gram-positive bacteria than the Gram-negative bacteria. The present studies clearly establish the potential of the fruits of Q. leucotrichophora for use in soap, cosmetics and pharmaceutical industries.

Analysis of fatty acid composition of sea cucumber Apostichopus japonicus using multivariate statistics

NASA Astrophysics Data System (ADS)

Xu, Qinzeng; Gao, Fei; Xu, Qiang; Yang, Hongsheng

2014-11-01

Fatty acids (FAs) provide energy and also can be used to trace trophic relationships among organisms. Sea cucumber Apostichopus japonicus goes into a state of aestivation during warm summer months. We examined fatty acid profiles in aestivated and non-aestivated A. japonicus using multivariate analyses (PERMANOVA, MDS, ANOSIM, and SIMPER). The results indicate that the fatty acid profiles of aestivated and non-aestivated sea cucumbers differed significantly. The FAs that were produced by bacteria and brown kelp contributed the most to the differences in the fatty acid composition of aestivated and nonaestivated sea cucumbers. Aestivated sea cucumbers may synthesize FAs from heterotrophic bacteria during early aestivation, and long chain FAs such as eicosapentaenoic (EPA) and docosahexaenoic acid (DHA) that produced from intestinal degradation, are digested during deep aestivation. Specific changes in the fatty acid composition of A. japonicus during aestivation needs more detailed study in the future.

Can the fatty acid selectivity of plant lipases be predicted from the composition of the seed triglyceride?

PubMed

Hellyer, S A; Chandler, I C; Bosley, J A

1999-09-22

To address the question can the fatty acid selectivity of plant lipases be predicted from the composition of the seed triglyceride, we have characterised the selectivity of lipases from a wide range of oilseeds with diverse fatty acid compositions. For this study, a novel hydrolysis assay using a fully randomised oil, was developed. From some seed sources (e.g. Cinnamomum camphora), lipases show high preference for particular fatty acids, whilst from others (e.g. Brassica napus, Theobroma cacao80% saturated or 'unusual' fatty acids may contain lipases which exhibit selectivity. It therefore follows that since the majority of seeds are composed of unsaturated fatty acids, that highly selective lipases will be unusual in nature. However lipases from some species of the Cuphea genera show exceptionally high preference for particular fatty acids. For example, lipase from seeds of Cuphea procumbans has over 20-fold selectivity for C10:0.

[Amino acid composition of the rat quadriceps femoris muscle after a flight on the Kosmos-936 biosatellite].

PubMed

Vlasova, T F; Miroshnikova, E B; Poliakov, V V; Murugova, T P

1982-01-01

The amino acid composition of the quadriceps muscle of rats flown onboard the biosatellite Cosmos-936 and exposed to the ground-based synchronous control experiment was studied. The weightless rats showed changes in the amino acid concentration in the quadriceps muscle. The centrifuged flight and synchronous rats displayed an accumulation of free amino acids in the above muscle.

Vapour-phase method in the synthesis of polymer-ibuprofen sodium-silica gel composites.

PubMed

Kierys, Agnieszka; Krasucka, Patrycja; Grochowicz, Marta

2017-11-01

The study discusses the synthesis of polymer-silica composites comprising water soluble drug (ibuprofen sodium, IBS). The polymers selected for this study were poly(TRIM) and poly(HEMA- co -TRIM) produced in the form of permanently porous beads via the suspension-emulsion polymerization method. The acid and base set ternary composites were prepared by the saturation of the solid dispersions of drug (poly(TRIM)-IBS and/or poly(HEMA- co -TRIM)-IBS) with TEOS, and followed by their exposition to the vapour mixture of water and ammonia, or water and hydrochloric acid, at autogenous pressure. The conducted analyses reveal that the internal structure and total porosity of the resulting composites strongly depend on the catalyst which was used for silica precursor gelation. The parameters characterizing the porosity of both of the acid set composites are much lower than the parameters of the base set composites. Moreover, the basic catalyst supplied in the vapour phase does not affect the ibuprofen sodium molecules, whereas the acid one causes transformation of the ibuprofen sodium into the sodium chloride and a derivative of propanoic acid, which is poorly water soluble. The release profiles of ibuprofen sodium from composites demonstrate that there are differences in the rate and efficiency of drug desorption from them. They are mainly affected by the chemical character of the polymeric carrier but are also associated with the restricted swelling of the composites in the buffer solution after precipitation of silica gel.

Ingredient selection for plastic composite supports for L-(+)-lactic acid biofilm fermentation by Lactobacillus casei subsp. rhamnosus.

PubMed Central

Ho, K L; Pometto, A L; Hinz, P N; Dickson, J S; Demirci, A

1997-01-01

Plastic composite supports containing 50% agricultural products (oat hulls, soybean hulls, yeast extract, soybean flour, dried bovine erythrocytes, bovine albumin, and/or mineral salts) and 50% (wt/wt) polypropylene were produced by high-temperature twin-screw extrusion. The research employed two half sets of a five-factorial fractional design (2(5 - 1)) to evaluate the effects of different agricultural components on the properties of the plastic composite supports and to select the best plastic composite support formulation for lactic acid fermentation. The biofilm population was affected by the contact angle and relative hydrophobicity of the supports (r = 0.79 to 0.82). Lactic acid was produced by the suspended cells (r = 0.96) and the biofilm on the plastic composite support discs (r = 0.85). Incorporation of yeast extract into plastic composite supports enhanced growth of free and attached cells in minimal medium (P < 0.0001). The presence of soybean hulls, yeast extract, or mineral salts in plastic composite supports produced less hydrophobic supports (P < 0.0001) and enhanced cell attachment (P < 0.03). Under all conditions, suspended-cell and polypropylene disc controls gave negligible lactic acid production and cell density. Plastic composite supports containing soybean hulls, yeast extract, soybean flour, bovine albumin, and mineral salts gave the highest biofilm population (2.3 x 10(9) CFU/g of support), cell density (absorbance of 1.8 at 620 nm), and lactic acid concentration (7.6 g/liter) in minimal medium. PMID:9212402

Differences in the fatty-acid composition of rodent spermatozoa are associated to levels of sperm competition

PubMed Central

delBarco-Trillo, Javier; Mateo, Rafael; Roldan, Eduardo R. S.

2015-01-01

Sperm competition is a prevalent phenomenon that drives the evolution of sperm function. High levels of sperm competition lead to increased metabolism to fuel higher sperm velocities. This enhanced metabolism can result in oxidative damage (including lipid peroxidation) and damage to the membrane. We hypothesized that in those species experiencing high levels of sperm competition there are changes in the fatty-acid composition of the sperm membrane that makes the membrane more resistant to oxidative damage. Given that polyunsaturated fatty acids (PUFAs) are the most prone to lipid peroxidation, we predicted that higher sperm competition leads to a reduction in the proportion of sperm PUFAs. In contrast, we predicted that levels of sperm competition should not affect the proportion of PUFAs in somatic cells. To test these predictions, we quantified the fatty-acid composition of sperm, testis and liver cells in four mouse species (genus Mus) that differ in their levels of sperm competition. Fatty-acid composition in testis and liver cells was not associated to sperm competition levels. However, in sperm cells, as predicted, an increase in sperm competition levels was associated with an increase in the proportion of saturated fatty-acids (the most resistant to lipid peroxidation) and by a concomitant decrease in the proportion of PUFAs. Two particular fatty acids were most responsible for this pattern (arachidonic acid and palmitic acid). Our findings thus indicate that sperm competition has a pervasive influence in the composition of sperm cells that ultimately may have important effects in sperm function. PMID:25795911

Elevational Variation in Soil Amino Acid and Inorganic Nitrogen Concentrations in Taibai Mountain, China.

PubMed

Cao, Xiaochuang; Ma, Qingxu; Zhong, Chu; Yang, Xin; Zhu, Lianfeng; Zhang, Junhua; Jin, Qianyu; Wu, Lianghuan

2016-01-01

Amino acids are important sources of soil organic nitrogen (N), which is essential for plant nutrition, but detailed information about which amino acids predominant and whether amino acid composition varies with elevation is lacking. In this study, we hypothesized that the concentrations of amino acids in soil would increase and their composition would vary along the elevational gradient of Taibai Mountain, as plant-derived organic matter accumulated and N mineralization and microbial immobilization of amino acids slowed with reduced soil temperature. Results showed that the concentrations of soil extractable total N, extractable organic N and amino acids significantly increased with elevation due to the accumulation of soil organic matter and the greater N content. Soil extractable organic N concentration was significantly greater than that of the extractable inorganic N (NO3--N + NH4+-N). On average, soil adsorbed amino acid concentration was approximately 5-fold greater than that of the free amino acids, which indicates that adsorbed amino acids extracted with the strong salt solution likely represent a potential source for the replenishment of free amino acids. We found no appreciable evidence to suggest that amino acids with simple molecular structure were dominant at low elevations, whereas amino acids with high molecular weight and complex aromatic structure dominated the high elevations. Across the elevational gradient, the amino acid pool was dominated by alanine, aspartic acid, glycine, glutamic acid, histidine, serine and threonine. These seven amino acids accounted for approximately 68.9% of the total hydrolyzable amino acid pool. The proportions of isoleucine, tyrosine and methionine varied with elevation, while soil major amino acid composition (including alanine, arginine, aspartic acid, glycine, histidine, leucine, phenylalanine, serine, threonine and valine) did not vary appreciably with elevation (p>0.10). The compositional similarity of many amino acids across the elevational gradient suggests that soil amino acids likely originate from a common source or through similar biochemical processes.

Elevational Variation in Soil Amino Acid and Inorganic Nitrogen Concentrations in Taibai Mountain, China

PubMed Central

Yang, Xin; Zhu, Lianfeng; Zhang, Junhua; Jin, Qianyu; Wu, Lianghuan

2016-01-01

Amino acids are important sources of soil organic nitrogen (N), which is essential for plant nutrition, but detailed information about which amino acids predominant and whether amino acid composition varies with elevation is lacking. In this study, we hypothesized that the concentrations of amino acids in soil would increase and their composition would vary along the elevational gradient of Taibai Mountain, as plant-derived organic matter accumulated and N mineralization and microbial immobilization of amino acids slowed with reduced soil temperature. Results showed that the concentrations of soil extractable total N, extractable organic N and amino acids significantly increased with elevation due to the accumulation of soil organic matter and the greater N content. Soil extractable organic N concentration was significantly greater than that of the extractable inorganic N (NO3−-N + NH4+-N). On average, soil adsorbed amino acid concentration was approximately 5-fold greater than that of the free amino acids, which indicates that adsorbed amino acids extracted with the strong salt solution likely represent a potential source for the replenishment of free amino acids. We found no appreciable evidence to suggest that amino acids with simple molecular structure were dominant at low elevations, whereas amino acids with high molecular weight and complex aromatic structure dominated the high elevations. Across the elevational gradient, the amino acid pool was dominated by alanine, aspartic acid, glycine, glutamic acid, histidine, serine and threonine. These seven amino acids accounted for approximately 68.9% of the total hydrolyzable amino acid pool. The proportions of isoleucine, tyrosine and methionine varied with elevation, while soil major amino acid composition (including alanine, arginine, aspartic acid, glycine, histidine, leucine, phenylalanine, serine, threonine and valine) did not vary appreciably with elevation (p>0.10). The compositional similarity of many amino acids across the elevational gradient suggests that soil amino acids likely originate from a common source or through similar biochemical processes. PMID:27337100

Fatty Acid Compositions of Six Wild Edible Mushroom Species

PubMed Central

Günç Ergönül, Pelin; Akata, Ilgaz; Kalyoncu, Fatih; Ergönül, Bülent

2013-01-01

The fatty acids of six wild edible mushroom species (Boletus reticulatus, Flammulina velutipes var. velutipes, Lactarius salmonicolor, Pleurotus ostreatus, Polyporus squamosus, and Russula anthracina) collected from different regions from Anatolia were determined. The fatty acids were identified and quantified by gas chromatography and studied using fruit bodies. Fatty acid composition varied among species. The dominant fatty acid in fruit bodies of all mushrooms was cis-linoleic acid (18 : 2). Percentage of cis-linoleic acid in species varied from 22.39% to 65.29%. The other major fatty acids were, respectively, cis-oleic, palmitic, and stearic acids. Fatty acids analysis of the mushrooms showed that the unsaturated fatty acids were at higher concentrations than saturated fatty acids. PMID:23844377

Abiotic condensation synthesis of glyceride lipids and wax esters under simulated hydrothermal conditions.

PubMed

Rushdi, Ahmed I; Simoneit, Bernd R T

2006-04-01

Precursor compounds for abiotic proto cellular membranes are necessary for the origin of life. Amphipathic compounds such as fatty acids and acyl glycerols are important candidates for micelle/bilayer/vesicle formation. Two sets of experiments were conducted to study dehydration reactions of model lipid precursors in aqueous media to form acyl polyols and wax esters, and to evaluate the stability and reactions of the products at elevated temperatures. In the first set, mixtures of n-nonadecanoic acid and ethylene glycol in water, with and without oxalic acid, were heated at discrete temperatures from 150 ( composite function)C to 300 ( composite function)C for 72 h. The products were typically alkyl alkanoates, ethylene glycolyl alkanoates, ethylene glycolyl bis-alkanoates and alkanols. The condensation products had maximum yields between 150 ( composite function)C and 250 ( composite function)C, and were detectable and thus stable under hydrothermal conditions to temperatures < 300 ( composite function)C. In the second set of experiments, mixtures of n-heptanoic acid and glycerol were heated using the same experimental conditions, with and without oxalic acid, between 100 ( composite function)C and 250 ( composite function)C. The main condensation products were two isomers each of monoacylglycerols and diacylglycerols at all temperatures, as well as minor amounts of the fatty acid anhydride and methyl ester. The yield of glyceryl monoheptanoates generally increased with increasing temperature and glyceryl diheptanoates decreased noticeably with increasing temperature. The results indicate that condensation reactions and abiotic synthesis of organic lipid compounds under hydrothermal conditions occur easily, provided precursor concentrations are sufficiently high.

Contrasting effects of Bifidobacterium breve NCIMB 702258 and Bifidobacterium breve DPC 6330 on the composition of murine brain fatty acids and gut microbiota.

PubMed

Wall, Rebecca; Marques, Tatiana M; O'Sullivan, Orla; Ross, R Paul; Shanahan, Fergus; Quigley, Eamonn M; Dinan, Timothy G; Kiely, Barry; Fitzgerald, Gerald F; Cotter, Paul D; Fouhy, Fiona; Stanton, Catherine

2012-05-01

We previously showed that microbial metabolism in the gut influences the composition of bioactive fatty acids in host adipose tissue. This study compared the effect of dietary supplementation for 8 wk with human-derived Bifidobacterium breve strains on fat distribution and composition and the composition of the gut microbiota in mice. C57BL/6 mice (n = 8 per group) received B. breve DPC 6330 or B. breve NCIMB 702258 (10(9) microorganisms) daily for 8 wk or no supplement (controls). Tissue fatty acid composition was assessed by gas-liquid chromatography while 16S rRNA pyrosequencing was used to investigate microbiota composition. Visceral fat mass and brain stearic acid, arachidonic acid, and DHA were higher in mice supplemented with B. breve NCIMB 702258 than in mice in the other 2 groups (P < 0.05). In addition, both B. breve DPC 6330 and B. breve NCIMB 702258 supplementation resulted in higher propionate concentrations in the cecum than did no supplementation (P < 0.05). Compositional sequencing of the gut microbiota showed a tendency for greater proportions of Clostridiaceae (25%, 12%, and 18%; P = 0.08) and lower proportions of Eubacteriaceae (3%, 12%, and 13%; P = 0.06) in mice supplemented with B. breve DPC 6330 than in mice supplemented with B. breve NCIMB 702258 and unsupplemented controls, respectively. The response of fatty acid metabolism to administration of bifidobacteria is strain-dependent, and strain-strain differences are important factors that influence modulation of the gut microbial community by ingested microorganisms.

Properties of poly(lactic acid)/hydroxyapatite composite through the use of epoxy functional compatibilizers for biomedical application.

PubMed

Monmaturapoj, Naruporn; Srion, Autcharaporn; Chalermkarnon, Prasert; Buchatip, Suthawan; Petchsuk, Atitsa; Noppakunmongkolchai, Warobon; Mai-Ngam, Katanchalee

2017-08-01

A composite of 70/30 poly(lactic acid)/hydroxyapatite was systematically prepared using various amounts of glycidyl methacrylate as reactive compatibilizer or Joncryl ADR®-4368 containing nine glycidyl methacrylate functions as a chain extension/branching agent to improve the mechanical and biological properties for suitable usage as internal bone fixation devices. The effect of glycidyl methacrylate/Joncryl on mechanical properties of poly(lactic acid)/hydroxyapatite was investigated through flexural strength. Cell proliferation and differentiation of osteoblast-like MC3T3-E1 cells cultured on the composite samples were determined by Alamar Blue assay and alkaline phosphatase expression, respectively. Result shows that flexural strength tends to decrease, as glycidyl methacrylate content increases except for 1 wt.% glycidyl methacrylate. With an addition of dicumyl peroxide, the flexural strength shows an improvement than that of without dicumyl peroxide probably due to the chemical bonding of the hydroxyapatite and poly(lactic acid) as revealed by FTIR and NMR, whereas the composite with 5 wt.% Joncryl shows the best result, as the flexural strength increases getting close to pure poly(lactic acid). The significant morphology change could be seen in composite with Joncryl where the uniform agglomeration of hydroxyapatite particles oriented in poly(lactic acid) matrix. Addition of the epoxy functional compatibilizers at suitable percentages could also have benefits to cellular attachment, proliferation, differentiation and mineralization. So that, this poly(lactic acid)/hydroxyapatite composite could be a promising material to be used as internal bone fixation devices such as screws, pins and plates.

[Relationship between dietary pattern and maternal state of fatty acids during pregnancy in three regions of China].

PubMed

Gao, Yixiong; Li, Yuqian; Wang, Chunrong; Li, Lixiang; Man, Qingqing; Zhang, Jian; Meng, Zhuoran

2016-05-01

To investigate the dietary pattern during pregnancy and the compositions of fatty acids of phosphatidylcholine (PC) during pregnancy in different regions of China. 35 Health women of each region were recruited from three different geographical regions in China: Jurong (an inland region close to freshwater), Rizhao (a coastal region) and Xushui (an inland region with limited access to freshwater). All women were long-term residents of their respective region. Their dietary status (including consumption frequency of food and consumption of culinary oil) during second trimester pregnancy was recorded and the fatty acid composition of PC in plasma during late pregnancy (34 weeks gestation) was quantified by GC. The consumption frequency of marine fish in Rizhao was significant higher than in other two regions. The main n-3 polyunsaturated fatty acids of PC in plasma was docosahexaenoic acid (DHA) in all regions. The composition of DHA in three regions were (3.31 +/- 0.77) %, (3.74 +/- 1.21) % and (2.44 +/- 0.63) %, respectively. The composition of DHA in Xushui was significant lower than in other two regions (P < 0.017). There was positive relationship between consumption frequency of marine fish and composition of DHA of PC in plasma (r = 0.337, P < 0.05). There was relationship between pregnant women's fatty acids composition of PC in plasma and their dietary. The consumption of food with high content of n-3 long chain polyunsaturated fatty acids during pregnancy would be more practical for DHA store of pregnant women.

Influence of Glyceride Structure and Fatty Acid Composition on Fat Nutrition.

DTIC Science & Technology

1981-02-25

11-eicosaenoic acid ), decreasing the chain length (9- hexadecenoic acid ), and changing the position of the double bond (6-octadecenofc acid ) reduced...AD-AU97 422 NORTH CAROLINA STATE l*JIV RALEIGH F/B 6/1 I NFLUENCE OF GLYCERIDE STRUCTURE AND FATTY ACID COMPOSITION O -TI UCAS FIEFB RI S B OE DAA62...78-G-0006 UNCLSSIIEDARO 14728.2-L NL 11111125 I’ *1. MIKIRO(A)PY R( S(LUTION fl->1 CHART LEVEL "Influence of Glyceride Structure and Fatty Acid

Impact of land-use and long-term (>150 years) charcoal accumulation on microbial activity, biomass and community structure in temperate soils (Belgium).

NASA Astrophysics Data System (ADS)

Hardy, Brieuc; Cornelis, Jean-Thomas; Dufey, Joseph E.

2015-04-01

In the last decade, biochar has been increasingly investigated as a soil amendment for long-term soil carbon sequestration while improving soil fertility. On the short term, biochar application to soil generally increases soil respiration as well as microbial biomass and activity and affects significantly the microbial community structure. However, such effects are relatively short-term and tend to vanish over time. In our study, we investigated the long-term impact of charcoal accumulation and land-use on soil biota in temperate haplic Luvisols developed in the loess belt of Wallonia (Belgium). Charcoal-enriched soils were collected in the topsoil of pre-industrial (>150 years old) charcoal kilns in forest (4 sites) and cropland (5 sites). The topsoil of the adjacent charcoal-unaffected soils was sampled in a comparable way. Soils were characterized (pH, total, organic and inorganic C, total N, exchangeable Ca, Mg, K, Na, cation exchange capacity and available P) and natural soil organic matter (SOM) and black carbon (BC) contents were determined by differential scanning calorimetry. After rewetting at pF 2.5, soils were incubated during 140 days at 20 °C. At 70 days of incubation, 10 g of each soil were freeze dried in order to measure total microbial biomass and community structure by PLFA analysis. The PLFA dataset was analyzed by principal component analysis (PCA) while soil parameters were used as supplementary variables. For both agricultural and forest soils, the respiration rate is highly related to the total microbial biomass (R²=0.90). Both soil respiration and microbial biomass greatly depend on the SOM content, which indicates that the BC pool is relatively inert microbiologically. Land-use explains most of the variance in the PLFA dataset, largely governing the first principal component of the ACP. In forest soils, we observe a larger proportion of gram + bacteria, actinomycetes and an increased bacteria:fungi ratio compared to cropland, where gram - bacteria, arbuscular mycorrhizal fungi and 18:2 and 18:3 fungi are more present. BC is quite well represented (R=-0.765) by the third principal component of the PCA, representing 12.2 % of the total variance. It has limited impact on the community structure, particularly in cropland. However, in forest BC is negatively correlated (R=-0.785) with 18:1 fungi. The more pronounced effect of BC on community structure under forest could result from modified trophic conditions at kiln site (e.g. higher pH, lower available P content, …) while cultivation practices attenuated such differences over time in cropland. In conclusion, our survey tends to confirm that the influence of BC on the soil microbiological parameters is governed by indirect effects on trophic conditions. On the other hand, land-use affects dramatically soil microbial community structure.

Preparation and characterization of acorn starch/poly(lactic acid) composites modified with functionalized vegetable oil derivates.

PubMed

Li, Shouhai; Xia, Jianling; Xu, Yuzhi; Yang, Xuejuan; Mao, Wei; Huang, Kun

2016-05-20

Composites of acorn starch (AS) and poly(1actic acid) (PLA) modified with dimer fatty acid (DFA) or dimer fatty acid polyamide (DFAPA) were produced by a hot-melt extrusion method. The effects of DFA and DFAPA contents on the mechanical, hydrophobic, thermal properties and melt fluidity of the composites were studied under an invariable AS-to-PLA mass ratio of 40/60. SEM and DMA research results show that the compatibility of AS/PLA composites are determined by the dosage of DFA or DFAPA. The hydrophobicity and melt fluidity of composites are improved with the addition of DFA and DFAPA. The glass transition temperatures of the composites are all reduced remarkably by additives DFA and DFAPA. However, DFA and DFAPA exert different effects on the mechanical properties of AS/PLA composites. In the DFAPA-modified system, the tensile and flexural strength first increase and then decrease with the increase of DFAPA dosage; the mechanical strength is maximized when the dosage of DFAPA is 2 wt% of total weight. In the DFA-modified system, the tensile and flexural strength decrease with the increase of DFA dosage. Copyright © 2016 Elsevier Ltd. All rights reserved.

Molecular Insights into Plant-Microbial Processes and Carbon Storage in Mangrove Ecosystems

NASA Astrophysics Data System (ADS)

Romero, I. C.; Ziegler, S. E.; Fogel, M.; Jacobson, M.; Fuhrman, J. A.; Capone, D. G.

2009-12-01

Mangrove forests, in tropical and subtropical coastal zones, are among the most productive ecosystems, representing a significant global carbon sink. We report new molecular insights into the functional relationship among microorganisms, mangrove trees and sediment geochemistry. The interactions among these elements were studied in peat-based mangrove sediments (Twin Cays, Belize) subjected to a long-term fertilization experiment with N and P, providing an analog for eutrophication. The composition and δ13C of bacterial PLFA showed that bacteria and mangrove trees had similar nutrient limitation patterns (N in the fringe mangrove zone, P in the interior zone), and that fertilization with N or P can affect bacterial metabolic processes and bacterial carbon uptake (from diverse mangrove sources including leaf litter, live and dead roots). PCR amplified nifH genes showed a high diversity (26% nifH novel clones) and a remarkable spatial and temporal variability in N-fixing microbial populations in the rhizosphere, varying primarily with the abundance of dead roots, PO4-3 and H2S concentrations in natural and fertilized environments. Our results indicate that eutrophication of mangrove ecosystems has the potential to alter microbial organic matter remineralization and carbon release with important implications for the coastal carbon budget. In addition, we will present preliminary data from a new study exploring the modern calibration of carbon and hydrogen isotopes of plant leaf waxes as a proxy recorder of past environmental change in mangrove ecosystems.

Cell cycle nucleic acids, polypeptides and uses thereof

DOEpatents

Gordon-Kamm, William J [Urbandale, IA; Lowe, Keith S [Johnston, IA; Larkins, Brian A [Tucson, AZ; Dilkes, Brian R [Tucson, AZ; Sun, Yuejin [Westfield, IN

2007-08-14

The invention provides isolated nucleic acids and their encoded proteins that are involved in cell cycle regulation. The invention further provides recombinant expression cassettes, host cells, transgenic plants, and antibody compositions. The present invention provides methods and compositions relating to altering cell cycle protein content, cell cycle progression, cell number and/or composition of plants.

Fatty acid composition of intramuscular fat from pastoral yak and Tibetan sheep

USDA-ARS?s Scientific Manuscript database

Fatty acid (FA) composition of intramuscular fat from mature male yak (n=6) and mature Tibetan sheep (n=6) grazed on the same pasture in the Qinghai-Tibetan Plateau was analyzed by gas chromatograph/mass spectrometer to characterize fat composition of these species and to evaluate possible differenc...

Mechanical properties of functionalised CNT filled kenaf reinforced epoxy composites

NASA Astrophysics Data System (ADS)

Sapiai, Napisah; Jumahat, Aidah; Mahmud, Jamaluddin

2018-04-01

This paper aims to study the effect of functionalised carbon nanotubes (CNT) on mechanical properties of kenaf fibre reinforced polymer composites. The CNT was functionalised using acid mixtures of H2SO4:HNO3 and 3-Aminopropyl Triethoxysilane before it was incorporated into epoxy resin. Three different types of CNT were used, i.e. pristine (PCNT), acid-treated (ACNT) and acid-silane treated (SCNT), to fabricate kenaf composite. Three different filler contents were mixed in each composite system, i.e. 0.5, 0.75 and 1.0 wt%. The functionalised CNT was characterized using x-ray Diffraction (XRD), Fourier Transform Infrared (FTIR) and Transmission Electron Microscopy (TEM). Tensile, flexural and Izod impact tests were conducted in order to evaluate the effect of CNT contents and surface treatment of mechanical properties of kenaf composites. It was observed that the inclusion of 1 wt% acid-silane treated CNT improved the tensile, flexural and impact strengths of kenaf/epoxy composite by 43.30%, 21.10%, and 130%, respectively. Silane modification had been proven to be beneficial in enhancing the dispersibility and reducing agglomeration of CNT in the epoxy matrix.

Composition and method to remove asbestos

DOEpatents

Block, Jacob

1998-05-19

A composition for transforming a chrysotile asbestos-containing material into a non-asbestos material is disclosed, wherein the composition comprises water, at least about 30% by weight of a boron tetrafluoride salt, free of or having only small amounts of an inorganic acid, an inorganic acid salt or a mixture thereof. A method of transforming the asbestos-containing material into a non-asbestos material using the present composition also is disclosed.

Composition and method to remove asbestos

DOE Office of Scientific and Technical Information (OSTI.GOV)

Block, J.

A composition for transforming a chrysotile asbestos-containing material into a non-asbestos material is disclosed. The composition comprises water, at least about 30% by weight of a boron tetrafluoride salt, free of or having only small amounts of an inorganic acid, an inorganic acid salt or a mixture thereof. A method of transforming the asbestos-containing material into a non-asbestos material using the present composition also is disclosed.

Composition and method to remove asbestos

DOEpatents

Block, J.

1998-05-19

A composition for transforming a chrysotile asbestos-containing material into a non-asbestos material is disclosed. The composition comprises water, at least about 30% by weight of a hexafluorosilicate salt, and free of or having only small amounts of an inorganic acid, an inorganic acid salt or a mixture thereof. A method of transforming the asbestos-containing material into a non-asbestos material using the present composition also is disclosed.

Composition and method to remove asbestos

DOE Office of Scientific and Technical Information (OSTI.GOV)

Block, J.

A composition for transforming a chrysotile asbestos-containing material into a non-asbestos material is disclosed. The composition comprises water, at least about 30% by weight of a hexafluorosilicate salt, and free of or having only small amounts of an inorganic acid, an inorganic acid salt or a mixture thereof. A method of transforming the asbestos-containing material into a non-asbestos material using the present composition also is disclosed.

Composition and method to remove asbestos

DOE Office of Scientific and Technical Information (OSTI.GOV)

Block, Jacob

A composition for transforming a chrysotile asbestos-containing material into a non-asbestos material is disclosed, wherein the composition comprises water, at least about 30% by weight of a hexafluorosilicate salt, and free of or having only small amounts of an inorganic acid, an inorganic acid salt or a mixture thereof. A method of transforming the asbestos-containing material into a non-asbestos material using the present composition also is disclosed.

Composition and method to remove asbestos

DOEpatents

Block, J.

1998-05-19

A composition for transforming a chrysotile asbestos-containing material into a non-asbestos material is disclosed. The composition comprises water, at least about 30% by weight of a boron tetrafluoride salt, free of or having only small amounts of an inorganic acid, an inorganic acid salt or a mixture thereof. A method of transforming the asbestos-containing material into a non-asbestos material using the present composition also is disclosed.

Cluster shading modifies amino acids in grape (Vitis vinifera L.) berries in a genotype- and tissue-dependent manner.

PubMed

Guan, Le; Wu, Benhong; Hilbert, Ghislaine; Li, Shaohua; Gomès, Eric; Delrot, Serge; Dai, Zhanwu

2017-08-01

Amino acid composition of the grape berry at harvest is important for wine making. The present study investigates the complex interplay between tissue, cultivar and light conditions that determine berry amino acid content. Twenty amino acids were assessed in the berry skin and pulp of two grape cultivars (Gamay Noir and Gamay Fréaux), grown under either light exposure or cluster shading conditions. In all samples, cluster shading significantly reduced most amino acids, except gamma-aminobutyric acid (GABA) and phenylalanine. However, the magnitude of the decrease was stronger in the skin (67.0% decrease) than in the pulp (30.4%) and stronger in cv. Gamay Noir (69.7%) than in Gamay Fréaux (30.7%). Cluster shading also significantly modified amino acid composition by decreasing the proline content while increasing the GABA content. These results are of oenological interest for shaping the amino acid composition of the must and improving wine quality. Copyright © 2017 Elsevier Ltd. All rights reserved.

Total lipid and fatty acid composition of eight strains of marine diatoms

NASA Astrophysics Data System (ADS)

Liang, Ying; Mai, Kang-Sen; Sun, Shi-Chun

2000-12-01

Fatty acid composition and total lipid content of 8 strains of marine diatoms ( Nitzschia frustrula, Nitzschia closterium, Nitzschia incerta, Navicula pelliculosa, Phaeodactylum tricornutum, Synedra fragilaroides) were examined. The microalgae were grown under defined conditions and harvested at the late exponential phase. The major fatty acids in most strains were 14∶0 (1.0% 6.3%), 16∶0 (13.5 26.4%), 16∶1n-7 (21.1% 46.3%) and 20∶5n-3 (6.5% 19.5%). The polyunsaturated fatty acids 16∶2n-4, 16∶3n-4, 16∶4n-1 and 20∶4n-6 also comprised a significant proportion of the total fatty acids in some strains. The characteristic fatty acid composition of diatoms is readily distinguishable from those of other microalgal groups. Significant concentration of the polyunsaturated fatty acid 20∶5n-3 (eicosapentaenoic acid) was present in each strain, with the highest proportion in B222 (19.5%).

Fatty acid composition indicating diverse habitat use in coral reef fishes in the Malaysian South China Sea.

PubMed

Arai, Takaomi; Amalina, Razikin; Bachok, Zainudin

2015-02-22

In order to understand feeding ecology and habitat use of coral reef fish, fatty acid composition was examined in five coral reef fishes, Thalassoma lunare, Lutjanus lutjanus, Abudefduf bengalensis, Scarus rivulatus and Scolopsis affinis collected in the Bidong Island of Malaysian South China Sea. Proportions of saturated fatty acids (SAFA) ranged 57.2% 74.2%, with the highest proportions in fatty acids, the second highest was monounsaturated fatty acids (MUFA) ranged from 21.4% to 39.0% and the proportion of polyunsaturated fatty acids (PUFA) was the lowest ranged from 2.8% to 14.1%. Each fatty acid composition differed among fishes, suggesting diverse feeding ecology, habitat use and migration during the fishes' life history in the coral reef habitats. Diets of the coral fish species might vary among species in spite of that each species are living sympatrically. Differences in fatty acid profiles might not just be considered with respect to the diets, but might be based on the habitat and migration.

Fatty acid composition and volatile compounds of caviar from farmed white sturgeon (Acipenser transmontanus).

PubMed

Caprino, Fabio; Moretti, Vittorio Maria; Bellagamba, Federica; Turchini, Giovanni Mario; Busetto, Maria Letizia; Giani, Ivan; Paleari, Maria Antonietta; Pazzaglia, Mario

2008-06-09

The present study was conducted to characterize caviar obtained from farmed white sturgeons (Acipenser transmontanus) subjected to different dietary treatments. Twenty caviar samples from fish fed two experimental diets containing different dietary lipid sources have been analysed for chemical composition, fatty acids and flavour volatile compounds. Fatty acid make up of caviar was only minimally influenced by dietary fatty acid composition. Irrespective of dietary treatments, palmitic acid (16:0) and oleic acid (OA, 18:1 n-9) were the most abundant fatty acid followed by docosahexaenoic acid (DHA, 22:6 n-3) and eicopentaenoic (EPA, 20:5 n-3). Thirty-three volatile compounds were isolated using simultaneous distillation-extraction (SDE) and identified by GC-MS. The largest group of volatiles were represented by aldehydes with 20 compounds, representing the 60% of the total volatiles. n-Alkanals, 2-alkenals and 2,4-alkadienals are largely the main responsible for a wide range of flavours in caviar from farmed white surgeon.

Preparation and analysis of multilayer composites based on polyelectrolyte complexes

NASA Astrophysics Data System (ADS)

Petrova, V. A.; Orekhov, A. S.; Chernyakov, D. D.; Baklagina, Yu. G.; Romanov, D. P.; Kononova, S. V.; Volod'ko, A. V.; Ermak, I. M.; Klechkovskaya, V. V.; Skorik, Yu. A.

2016-11-01

A method for preparing multilayer film composites based on chitosan has been developed by the example of polymer pairs: chitosan-hyaluronic acid, chitosan-alginic acid, and chitosan-carrageenan. The structure of the composite films is characterized by X-ray diffractometry and scanning electron microscopy. It is shown that the deposition of a solution of hyaluronic acid, alginic acid, or carrageenan on a chitosan gel film leads to the formation of a polyelectrolyte complex layer at the interface, which is accompanied by the ordering of chitosan chains in the surface region; the microstructure of this layer depends on the nature of contacting polymer pairs.

Tutorial for Collecting and Processing Images of Composite Structures to Determine the Fiber Volume Fraction

NASA Technical Reports Server (NTRS)

Conklin, Lindsey

2017-01-01

Fiber-reinforced composite structures have become more common in aerospace components due to their light weight and structural efficiency. In general, the strength and stiffness of a composite structure are directly related to the fiber volume fraction, which is defined as the fraction of fiber volume to total volume of the composite. The most common method to measure the fiber volume fraction is acid digestion, which is a useful method when the total weight of the composite, the fiber weight, and the total weight can easily be obtained. However, acid digestion is a destructive test, so the material will no longer be available for additional characterization. Acid digestion can also be difficult to machine out specific components of a composite structure with complex geometries. These disadvantages of acid digestion led the author to develop a method to calculate the fiber volume fraction. The developed method uses optical microscopy to calculate the fiber area fraction based on images of the cross section of the composite. The fiber area fraction and fiber volume fraction are understood to be the same, based on the assumption that the shape and size of the fibers are consistent in the depth of the composite. This tutorial explains the developed method for optically determining fiber area fraction performed at NASA Langley Research Center.

Synergistic Removal of Pb(II), Cd(II) and Humic Acid by Fe3O4@Mesoporous Silica-Graphene Oxide Composites

PubMed Central

Wang, Yilong; Liang, Song; Chen, Bingdi; Guo, Fangfang; Yu, Shuili; Tang, Yulin

2013-01-01

The synergistic adsorption of heavy metal ions and humic acid can be very challenging. This is largely because of their competitive adsorption onto most adsorbent materials. Hierarchically structured composites containing polyethylenimine-modified magnetic mesoporous silica and graphene oxide (MMSP-GO) were here prepared to address this. Magnetic mesoporous silica microspheres were synthesized and functionalized with PEI molecules, providing many amine groups for chemical conjugation with the carboxyl groups on GO sheets and enhanced the affinity between the pollutants and the mesoporous silica. The features of the composites were characterized using TEM, SEM, TGA, DLS, and VSM measurements. Series adsorption results proved that this system was suitable for simultaneous and efficient removal of heavy metal ions and humic acid using MMSP-GO composites as adsorbents. The maximum adsorption capacities of MMSP-GO for Pb(II) and Cd (II) were 333 and 167 mg g−1 caculated by Langmuir model, respectively. HA enhances adsorption of heavy metals by MMSP-GO composites due to their interactions in aqueous solutions. The underlying mechanism of synergistic adsorption of heavy metal ions and humic acid were discussed. MMSP-GO composites have shown promise for use as adsorbents in the simultaneous removal of heavy metals and humic acid in wastewater treatment processes. PMID:23776514

Liposomes as carriers of macrolides: preferential association of erythromycin A and azithromycin with liposomes of phosphatidylglycerol containing unsaturated fatty acid(s).

PubMed

Stuhne-Sekalec, L; Stanacev, N Z; Djokic, S

1991-01-01

To assess the most favourable phospholipid composition of a liposomal carrier for antibiotics, small multilamellar liposomes were prepared from phosphatidylcholine, phosphatidylethanolamine and phosphatidylglycerol of varying fatty acid composition in the presence of erythromycin A and azithromycin. Crude liposomes were subjected to Sepharose CL-4B column chromatography, and liposomes containing antibiotics were well separated from free antibiotics. These experiments established that the greatest association of antibiotics was achieved with liposomes prepared from phosphatidylglycerol rather than phosphatidylcholine or phosphatidylethanolamine. Furthermore, the composition of fatty acids in phosphatidylglycerol liposomes influenced the amount of antibiotics associated with liposomes; the highest amount was obtained with dioleoylphosphatidylglycerol followed by phosphatidylglycerol of fatty acid composition similar to that of egg yolk lecithin. It was established that purified liposomes, prepared from [3H]phosphatidylglycerol containing unsaturated fatty acid(s) bind about 25 per cent of originally present antibiotic. Both antibiotics, erythromycin A and azithromycin, were similar in respect to the amount of their association with liposomes. Determination of the size of phosphatidylglycerol/antibiotic liposomes established that the mean diameter of liposomes containing antibiotics was 200-350 nm, very close to that of liposomes without them.

Relationships between botanical and chemical composition of forages: a multivariate approach to grasslands in the Western Italian Alps.

PubMed

Ravetto Enri, Simone; Renna, Manuela; Probo, Massimiliano; Lussiana, Carola; Battaglini, Luca M; Lonati, Michele; Lombardi, Giampiero

2017-03-01

Plant composition of species-rich mountain grasslands can affect the sensorial and chemical attributes of dairy and meat products, with implications for human health. A multivariate approach was used to analyse the complex relationships between vegetation characteristics (botanical composition and plant community variables) and chemical composition (proximate constituents and fatty acid profile) in mesophilic and dry vegetation ecological groups, comprising six different semi-natural grassland types in the Western Italian Alps. Mesophilic and dry grasslands were comparable in terms of phenology, biodiversity indices and proportion of botanical families. The content of total fatty acids and that of the most abundant fatty acids (alpha-linolenic, linoleic and palmitic acids) were mainly associated to nutrient-rich plant species, belonging to the mesophilic grassland ecological group. Mesophilic grasslands showed also higher values of crude protein, lower values of fibre content and they were related to higher pastoral values of vegetation compared to dry grasslands. The proximate composition and fatty acid profile appeared mainly single species dependent rather than botanical family dependent. These findings highlight that forage from mesophilic grasslands can provide higher nutritive value for ruminants and may be associated to ruminant-derived food products with a healthier fatty acid profile. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Impact of potato psyllid (Hemiptera: Triozide) feeding on free amino acid composition in potato

USDA-ARS?s Scientific Manuscript database

Foliage feeding impacts of potato psyllid (Bactericera cockerelli) on the free amino acids (FAAs) composition in potato leaf and tuber were determined under the greenhouse conditions. The free amino acids in plant extracts were separated by HPLC, and in both leaf and tuber samples, at least, 17 FAAs...

Effects of a combination of elicitation and precursor feeding on grape amino acid composition through foliar applications to Garnacha vineyard.

PubMed

Gutiérrez-Gamboa, Gastón; Portu, Javier; López, Rosa; Santamaría, Pilar; Garde-Cerdán, Teresa

2018-04-01

Vine foliar applications of phenylalanine (Phe) or methyl jasmonate (MeJ) could improve the synthesis of secondary metabolites. However, there are no reports focusing on the effects of elicitation supported by precursor feeding on must amino acid composition in grapevines. The aim of this research was to study the effect of the elicitation of methyl jasmonate (MeJ) supported by phenylalanine (Phe) as a precursor feeding (MeJ+Phe) and its application individually on must amino acid composition. Results showed that foliar Phe and MeJ treatments decreased the concentration of most of the studied amino acids with respect to the control (p≤0.05). MeJ+Phe treatment did not affect must nitrogen content. Musts obtained from MeJ+Phe showed higher concentration of several amino acids than samples from Phe and MeJ applications. Therefore, other sources of precursor feeding could support elicitation, to improve amino acid composition and be considered as a tool for viticulture. Copyright © 2017 Elsevier Ltd. All rights reserved.

Polymorphisms in lipogenic genes and milk fatty acid composition in Holstein dairy cattle.

PubMed

Nafikov, Rafael A; Schoonmaker, Jon P; Korn, Kathleen T; Noack, Kristin; Garrick, Dorian J; Koehler, Kenneth J; Minick-Bormann, Jennifer; Reecy, James M; Spurlock, Diane E; Beitz, Donald C

2014-12-01

Changing bovine milk fatty acid (FA) composition through selection can decrease saturated FA (SFA) consumption, improve human health and provide a means for manipulating processing properties of milk. Our study determined associations between milk FA composition and genes from triacylglycerol (TAG) biosynthesis pathway. The GC dinucleotide allele of diacylglycerol O-acyltransferase 1:g.10433-10434AA >GC was associated with lower palmitic acid (16:0) concentration but higher oleic (18:1 cis-9), linoleic (18:2 cis-9, cis-12) acid concentrations, and elongation index. Accordingly, the GC dinucleotide allele was associated with lower milk fat percentage and SFA concentrations but higher monounsaturated FA and polyunsaturated FA (PUFA) concentrations. The glycerol-3-phosphate acyltransferase, mitochondrial haplotypes were associated with higher myristoleic acid (14:1 cis-9) concentration and C14 desaturation index. The 1-acylglycerol-3-phosphate acyltransferase 1 haplotypes were associated with higher PUFA and linoleic acid concentrations. The results of this study provide information for developing genetic tools to modify milk FA composition in dairy cattle. Copyright © 2014 Elsevier Inc. All rights reserved.

Composition of precipitation in remote areas of the world

DOE Office of Scientific and Technical Information (OSTI.GOV)

Galloway, J.N.; Likens, G.E.; Keene, W.C.

1982-10-20

The Global Precipitation Chemistry Project collects precipitation by event to determine composition and processes controlling it in five remote areas. Compositions (excluding sea-salt) at St. Georges, Bermuda, were primarily controlled by anthropogenic processes; composition and acidities at San Carlos, Venezuela, Katherine, Australia, Poker Flat, Alaska, and Amsterdam Island were controlled by unknown mixtures of natural or anthropogenic processes. Precipitation was acidic; average volume-weighted pH values were 4.8 for Bermuda; 5.0, Alaska; 4.9, Amsterdam Island; 4.8, Australia; 4.8, Venezuela. Acidities at Bermuda and Alaska were from long-range transport of sulfate aerosol; at Venezuela, Australia, and Amsterdam Island, from mixtures of weakmore » organic and strong mineral acids, primarily H/sub 2/SO/sub 4/. Relative proportions of weak to strong acids were largest at Venezuela and lowest at Amsterdam Island. Weak and strong acids were from mixtures of natural and anthropogenic processes. Once contributions from human activities were removed, the lower limit of natural contributions was probably greater than or equal to pH 5.« less

Skeletal muscle phosphatidylcholine fatty acids and insulin sensitivity in normal humans.

PubMed

Clore, J N; Li, J; Gill, R; Gupta, S; Spencer, R; Azzam, A; Zuelzer, W; Rizzo, W B; Blackard, W G

1998-10-01

The fatty acid composition of skeletal muscle membrane phospholipids (PL) is known to influence insulin responsiveness in humans. However, the contribution of the major PL of the outer (phosphatidylcholine, PC) and inner (phosphatidylethanolamine, PE) layers of the sarcolemma to insulin sensitivity is not known. Fatty acid composition of PC and PE from biopsies of vastus lateralis from 27 normal men and women were correlated with insulin sensitivity determined by the hyperinsulinemic euglycemic clamp technique at insulin infusion rates of 0.4, 1.0, and 10.0 mU . kg-1 . min-1. Significant variation in the half-maximal insulin concentration (ED50) was observed in the normal volunteers (range 24.0-146.0 microU/ml), which correlated directly with fasting plasma insulin (r = 0.75, P < 0.0001). ED50 was inversely correlated with the degree of membrane unsaturation (C20-C22 polyunsaturated fatty acids; r = 0. 58, P < 0.01) and directly correlated with fatty acid elongation (ratio of 16:0 to 18:0, r = 0.45, P < 0.05) in PC. However, no relationship between fatty acid composition and insulin sensitivity was observed in PE (NS). These studies suggest that the fatty acid composition of PC may be of particular importance in the relationship between fatty acids and insulin sensitivity in normal humans.

Brittle and ductile adjustable cement derived from calcium phosphate cement/polyacrylic acid composites.

PubMed

Chen, Wen-Cheng; Ju, Chien-Ping; Wang, Jen-Chyan; Hung, Chun-Cheng; Chern Lin, Jiin-Huey

2008-12-01

Bone filler has been used over the years in dental and biomedical applications. The present work is to characterize a non-dispersive, fast setting, modulus adjustable, high bioresorbable composite bone cement derived from calcium phosphate-based cement combined with polymer and binding agents. This cement, we hope, will not swell in simulated body fluid and keep the osteogenetic properties of the dry bone and avoid its disadvantages of being brittle. We developed a calcium phosphate cement (CPC) of tetracalcium phosphate/dicalcium phosphate anhydrous (TTCP/DCPA)-polyacrylic acid with tartaric acid, calcium fluoride additives and phosphate hardening solution. The results show that while composite, the hard-brittle properties of 25wt% polyacrylic acid are proportional to CPC and mixing with additives is the same as those of the CPC without polyacrylic acid added. With an increase of polyacrylic acid/CPC ratio, the 67wt% samples revealed ductile-tough properties and 100wt% samples kept ductile or elastic properties after 24h of immersion. The modulus range of this development was from 200 to 2600MPa after getting immersed in simulated body fluid for 24h. The TTCP/DCPA-polyacrylic acid based CPC demonstrates adjustable brittle/ductile strength during setting and after immersion, and the final reaction products consist of high bioresorbable monetite/brushite/calcium fluoride composite with polyacrylic acid.

Dietary saturated and monounsaturated fats protect against acute acetaminophen hepatotoxicity by altering fatty acid composition of liver microsomal membrane in rats.

PubMed

Hwang, Jinah; Chang, Yun-Hee; Park, Jung Hwa; Kim, Soo Yeon; Chung, Haeyon; Shim, Eugene; Hwang, Hye Jin

2011-10-20

Dietary polyunsaturated fats increase liver injury in response to ethanol feeding. We evaluated the effect of dietary corn oil (CO), olive oil (OO), and beef tallow (BT) on fatty acid composition of liver microsomal membrane and acute acetaminophen hepatotoxicity. Male Sprague-Dawley rats were fed 15% (wt/wt) CO, OO or BT for 6 weeks. After treatment with acetaminophen (600 mg/kg), samples of plasma and liver were taken for analyses of the fatty acid composition and toxicity. Treatment with acetaminophen significantly elevated levels of plasma GOT and GPT as well as hepatic TBARS but reduced hepatic GSH levels in CO compared to OO and BT groups. Acetaminophen significantly induced protein expression of cytochrome P450 2E1 in the CO group. In comparison with the CO diet, lower levels of linoleic acid, higher levels of oleic acids and therefore much lower ratios of linoleic to oleic acid were detected in rats fed OO and BT diets. Dietary OO and BT produces similar liver microsomal fatty acid composition and may account for less severe liver injury after acetaminophen treatment compared to animals fed diets with CO rich in linoleic acid. These findings imply that types of dietary fat may be important in the nutritional management of drug-induced hepatotoxicity.

A nine-country study of the protein content and amino acid composition of mature human milk

PubMed Central

Feng, Ping; Gao, Ming; Burgher, Anita; Zhou, Tian Hui; Pramuk, Kathryn

2016-01-01

Background Numerous studies have evaluated protein and amino acid levels in human milk. However, research in this area has been limited by small sample sizes and study populations with little ethnic or racial diversity. Objective Evaluate the protein and amino acid composition of mature (≥30 days) human milk samples collected from a large, multinational study using highly standardized methods for sample collection, storage, and analysis. Design Using a single, centralized laboratory, human milk samples from 220 women (30–188 days postpartum) from nine countries were analyzed for amino acid composition using Waters AccQ-Tag high-performance liquid chromatography and total nitrogen content using the LECO FP-528 nitrogen analyzer. Total protein was calculated as total nitrogen×6.25. True protein, which includes protein, free amino acids, and peptides, was calculated from the total amino acids. Results Mean total protein from individual countries (standard deviation [SD]) ranged from 1,133 (125.5) to 1,366 (341.4) mg/dL; the mean across all countries (SD) was 1,192 (200.9) mg/dL. Total protein, true protein, and amino acid composition were not significantly different across countries except Chile, which had higher total and true protein. Amino acid profiles (percent of total amino acids) did not differ across countries. Total and true protein concentrations and 16 of 18 amino acid concentrations declined with the stage of lactation. Conclusions Total protein, true protein, and individual amino acid concentrations in human milk steadily decline from 30 to 151 days of lactation, and are significantly higher in the second month of lactation compared with the following 4 months. There is a high level of consistency in the protein content and amino acid composition of human milk across geographic locations. The size and diversity of the study population and highly standardized procedures for the collection, storage, and analysis of human milk support the validity and broad application of these findings. PMID:27569428

Assessment of oil content and fatty acid composition variability in two economically important Hibiscus species.

PubMed

Wang, Ming Li; Morris, Brad; Tonnis, Brandon; Davis, Jerry; Pederson, Gary A

2012-07-04

The Hibiscus genus encompasses more than 300 species, but kenaf (Hibiscus cannabinus L.) and roselle (Hibiscus sabdariffa L.) are the two most economically important species within the genus. Seeds from these two Hibiscus species contain a relatively high amount of oil with two unusual fatty acids: dihydrosterculic and vernolic acids. The fatty acid composition in the oil can directly affect oil quality and its utilization. However, the variability in oil content and fatty acid composition for these two species is unclear. For these two species, 329 available accessions were acquired from the USDA germplasm collection. Their oil content and fatty acid composition were determined by nuclear magnetic resonance (NMR) and gas chromatography (GC), respectively. Using NMR and GC analyses, we found that Hibiscus seeds on average contained 18% oil and seed oil was composed of six major fatty acids (each >1%) and seven minor fatty acids (each <1%). Hibiscus cannabinus seeds contained significantly higher amounts of oil (18.14%), palmitic (20.75%), oleic (28.91%), vernolic acids (VA, 4.16%), and significantly lower amounts of stearic (3.96%), linoleic (39.49%), and dihydrosterculic acids (DHSA, 1.08%) than H. sabdariffa seeds (17.35%, 18.52%, 25.16%, 3.52%, 4.31%, 44.72%, and 1.57%, respectively). For edible oils, a higher oleic/linoleic (O/L) ratio and lower level of DHSA are preferred, and for industrial oils a high level of VA is preferred. Our results indicate that seeds from H. cannabinus may be of higher quality than H. sabdariffa seeds for these reasons. Significant variability in oil content and major fatty acids was also detected within both species. The variability in oil content and fatty acid composition revealed from this study will be useful for exploring seed utilization and developing new cultivars in these Hibiscus species.

Manipulating Membrane Fatty Acid Compositions of Whole Plants with Tween-Fatty Acid Esters 1

PubMed Central

Terzaghi, William B.

1989-01-01

This paper describes a method for manipulating plant membrane fatty acid compositions without altering growth temperature or other conditions. Tween-fatty acid esters carrying specific fatty acids were synthesized and applied to various organs of plants growing axenically in glass jars. Treated plants incorporated large amounts of exogenous fatty acids into all acylated membrane lipids detected. Fatty acids were taken up by both roots and leaves. Fatty acids applied to roots were found in leaves, while fatty acids applied to leaves appeared in both leaves higher on the plant and in roots, indicating translocation (probably in the phloem). Foliar application was most effective; up to 20% of membrane fatty acids of leaves above the treated leaf and up to 40% of root membrane fatty acids were exogenously derived. Plants which took up exogenous fatty acids changed their patterns of fatty acid synthesis such that ratios of saturated to unsaturated fatty acids remained essentially unaltered. Fatty acid uptake was most extensively studied in soybean (Glycine max [L.] Merr.), but was also observed in other species, including maize (Zea mays L.), mung beans (Vigna radiata L.), peas (Pisum sativum L.), petunia (Petunia hybrida L.) and tomato (Lycopersicon esculentum Mill.). Potential applications of this system include studying internal transport of fatty acids, regulation of fatty acid and membrane synthesis, and influences of membrane fatty acid composition on plant physiology. Images Figure 2 PMID:16666997

Effect of boric acid on the properties of Li{sub 2}MnO{sub 3}·LiNi{sub 0.5}Mn{sub 0.5}O{sub 2} composite cathode powders prepared by large-scale spray pyrolysis with droplet classifier

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hong, Young Jun; Choi, Seung Ho; Sim, Chul Min

2012-12-15

Graphical abstract: Display Omitted Highlights: ► Spherical shape Li{sub 2}MnO{sub 3}·LiNi{sub 0.5}Mn{sub 0.5}O{sub 2} composite cathode powders are prepared by large-scale spray pyrolysis with droplet classifier. ► Boric acid improves the morphological and electrochemical properties of the composite cathode powders. ► The discharge capacity of the composite cathode powders decreases from 217 to 196 mAh g{sup −1} by the 30th cycle. -- Abstract: Spherically shaped 0.3Li{sub 2}MnO{sub 3}·0.7LiNi{sub 0.5}Mn{sub 0.5}O{sub 2} composite cathode powders with filled morphology and narrow size distribution are prepared by large-scale spray pyrolysis. A droplet classification reduces the standard deviation of the size distribution of themore » composite cathode powders. Addition of boric acid improves the morphological properties of the product powders by forming a lithium borate glass material with low melting temperature. The optimum amount of boric acid dissolved in the spray solution is 0.8 wt% of the composite powders. The powders prepared from the spray solution with 0.8 wt% boric acid have a mixed layered crystal structure comprising Li{sub 2}MnO{sub 3} and LiNi{sub 0.5}Mn{sub 0.5}O{sub 2} phases, thus forming a composite compound. The initial charge and discharge capacities of the composite cathode powders prepared from the 0.8 wt% boric acid spray solution are 297 and 217 mAh g{sup −1}, respectively. The discharge capacity of the powders decreases from 217 to 196 mAh g{sup −1} by the 30th cycle, in which the capacity retention is 90%.« less

Symbiotic zooxanthellae provide the host-coral Montipora digitata with polyunsaturated fatty acids.

PubMed

Papina, M; Meziane, T; van Woesik, R

2003-07-01

We compared the fatty acid composition of the host-coral Montipora digitata with the fatty acid composition in the coral's endosymbiotic dinoflagellates (zooxanthellae). Fatty acids as methyl esters were determined using gas chromatography (GC) and verified by GC-mass spectrometry. We found the main difference between the fatty acids in the host and their symbionts were that zooxanthellae supported higher proportions of polyunsaturated fatty acids. The presence of fatty acids specific to dinoflagellates (i.e. 18:4omega3, 22:5omega3 and 22:6omega3) in the host tissue suggests that zooxanthellae provide the coral host not only with saturated fatty acids, but also with diverse polyunsaturated fatty acids.

Study of morphology, chemical, and amino acid composition of red deer meat.

PubMed

Okuskhanova, Eleonora; Assenova, Bahytkul; Rebezov, Maksim; Amirkhanov, Kumarbek; Yessimbekov, Zhanibek; Smolnikova, Farida; Nurgazezova, Almagul; Nurymkhan, Gulnur; Stuart, Marilyne

2017-06-01

The aim of this study was to evaluate red deer (maral) meat quality based on chemical composition, pH, water-binding capacity (WBC), and amino acid content. Maral meat surface morphology measurements were obtained by scanning electron microscopy. Active acidity (pH) was determined by potentiometry. Samples were analyzed for WBC by exudation of moisture to a filter paper by the application of pressure. Chemical composition (moisture, protein, fat, and ash fractions) was obtained by drying at 150°C and by extraction, using ethylic ether, and ashing at 500-600°C. The amino acid composition was obtained by liquid chromatography. Maral meat, with a pH of 5.85 and an average moisture content of 76.82%, was found to be low in fat (2.26%). Its protein content was 18.71% while its ash content was 2.21%. The amino acid composition showed that lysine (9.85 g/100 g), threonine (5.38 g/100 g), and valine (5.84 g/100 g) predominated in maral meat, while phenylalanine (4.08 g/100 g), methionine (3.29 g/100 g), and tryptophan (0.94 g/100 g) were relatively low in maral meat compared to other meats. The average WBC was found to be 65.82% and WBC was found to inversely correlate with moisture content. Low-fat content, high mineral content, and balanced amino-acid composition qualify maral meat as a worthy dietary and functional food.

Thermal characteristic investigation of eutectic composite fatty acid as heat storage material for solar heating and cooling application

NASA Astrophysics Data System (ADS)

Thaib, R.; Fauzi, H.; Ong, H. C.; Rizal, S.; Mahlia, T. M. I.; Riza, M.

2018-03-01

A composite phase change material (CPCM) of myristic acid/palmitic acid/sodium myristate (MA/PA/SM) and of myristic acid/palmitic acid/sodium laurate (MA/PA/SL) were impregnated with purified damar gum as called Shorea Javanica (SJ) to improve the thermal conductivity of CPCM. The thermal properties, thermal conductivity, and thermal stability of both CPCM have investigated by using a Differential Scanning Calorimetry (DSC) thermal analysis, hot disc thermal conductivity analyzer, and Simultaneous Thermal Analyzer (STA), simultaneously. However, a chemical compatibility between both fatty acid eutectic mixtures and SJ in composite mixtures measured by Fourier Transform Infra-Red (FT-IR) spectrophotometer. The results were obtained that the thermal conductivity of MA/PA/SM/SJ and MA/PA/SL/SJ eutectic composite phase change material (CPCM) were improved by addition 3 wt.% and 2 wt.% of Shorea javanica (SJ), respectively, without occur a significant change on thermal properties of CPCM. Moreover, the absorbance spectrum of FT-IR shows the good compatibility of SJ with both MA/PA/SM and MA/PA/SL eutectic mixtures, the composite PCM also present good thermal performance and good thermal stability. Therefore, it can be noted that the purified Shorea Javanica proposed, the as high conductive material in this study was able to improve the thermal conductivity of eutectic PCM without any significant reduction on its thermo-physical and chemical properties and can be recommended as novelty composite phase change material for thermal energy storage application.

SURFACE DEGRADATION OF COMPOSITE RESINS BY ACIDIC MEDICINES AND pH-CYCLING

PubMed Central

Valinoti, Ana Carolina; Neves, Beatriz Gonçalves; da Silva, Eduardo Moreira; Maia, Lucianne Cople

2008-01-01

This study evaluated the effects of acidic medicines (Dimetapp® and Claritin®), under pH-cycling conditions, on the surface degradation of four composite resins (microhybrid: TPH, Concept, Opallis and Nanofilled: Supreme). Thirty disc-shaped specimens (Ø = 5.0 mm / thickness = 2.0 mm) of each composite were randomly assigned to 3 groups (n = 10): a control and two experimental groups, according to the acidic medicines evaluated. The specimens were finished and polished with aluminum oxide discs, and the surface roughness was measured by using a profilometer. After the specimens were submitted to a pH-cycling regimen and immersion in acidic medicines for 12 days, the surface roughness was measured again. Two specimens for each material and group were analyzed by scanning electron microscopy (SEM) before and after pH-cycling. Data were analyzed by the Student's-t test, ANOVA, Duncan's multiple range test and paired t-test (α=0.05). Significant increase in roughness was found only for TPH in the control group and TPH and Supreme immersed in Claritin® (p<0.05). SEM analyses showed that the 4 composite resins underwent erosion and surface degradation after being subjected to the experimental conditions. In conclusion, although the roughness was slightly affected, the pH-cycling and acidic medicines caused surface degradation of the composite resins evaluated. Titratable acidity seemed to play a more crucial role on surface degradation of composite resins than pH. PMID:19089257

Study of morphology, chemical, and amino acid composition of red deer meat

PubMed Central

Okuskhanova, Eleonora; Assenova, Bahytkul; Rebezov, Maksim; Amirkhanov, Kumarbek; Yessimbekov, Zhanibek; Smolnikova, Farida; Nurgazezova, Almagul; Nurymkhan, Gulnur; Stuart, Marilyne

2017-01-01

Aim: The aim of this study was to evaluate red deer (maral) meat quality based on chemical composition, pH, water-binding capacity (WBC), and amino acid content. Materials and Methods: Maral meat surface morphology measurements were obtained by scanning electron microscopy. Active acidity (pH) was determined by potentiometry. Samples were analyzed for WBC by exudation of moisture to a filter paper by the application of pressure. Chemical composition (moisture, protein, fat, and ash fractions) was obtained by drying at 150°C and by extraction, using ethylic ether, and ashing at 500-600°C. The amino acid composition was obtained by liquid chromatography. Results: Maral meat, with a pH of 5.85 and an average moisture content of 76.82%, was found to be low in fat (2.26%). Its protein content was 18.71% while its ash content was 2.21%. The amino acid composition showed that lysine (9.85 g/100 g), threonine (5.38 g/100 g), and valine (5.84 g/100 g) predominated in maral meat, while phenylalanine (4.08 g/100 g), methionine (3.29 g/100 g), and tryptophan (0.94 g/100 g) were relatively low in maral meat compared to other meats. The average WBC was found to be 65.82% and WBC was found to inversely correlate with moisture content. Conclusion: Low-fat content, high mineral content, and balanced amino-acid composition qualify maral meat as a worthy dietary and functional food. PMID:28717313

Lipid composition analysis of milk fats from different mammalian species: potential for use as human milk fat substitutes.

PubMed

Zou, Xiaoqiang; Huang, Jianhua; Jin, Qingzhe; Guo, Zheng; Liu, Yuanfa; Cheong, Lingzhi; Xu, Xuebing; Wang, Xingguo

2013-07-24

The lipid compositions of commercial milks from cow, buffalo, donkey, sheep, and camel were compared with that of human milk fat (HMF) based on total and sn-2 fatty acid, triacylglycerol (TAG), phospholipid, and phospholipid fatty acid compositions and melting and crystallization profiles, and their degrees of similarity were digitized and differentiated by an evaluation model. The results showed that these milk fats had high degrees of similarity to HMF in total fatty acid composition. However, the degrees of similarity in other chemical aspects were low, indicating that these milk fats did not meet the requirements of human milk fat substitutes (HMFSs). However, an economically feasible solution to make these milks useful as raw materials for infant formula production could be to modify these fats, and a possible method is blending of polyunsaturated fatty acids (PUFA) and 1,3-dioleoyl-2-palmitoylglycerol (OPO) enriched fats and minor lipids based on the corresponding chemical compositions of HMF.

Proximate composition and mineral content of two edible species of Cnidoscolus (tree spinach).

PubMed

Kuti, J O; Kuti, H O

1999-01-01

Proximate composition and mineral content of raw and cooked leaves of two edible tree spinach species (Cnidoscolus chayamansa and C. aconitifolius), known locally as 'chaya', were determined and compared with that of a traditional green vegetable, spinach (Spinicia oleraceae). Results of the study indicated that the edible leafy parts of the two chaya species contained significantly (p<0.05) greater amounts of crude protein, crude fiber, Ca, K, Fe, ascorbic acid and beta-carotene than the spinach leaf. However, no significant (p>0.05) differences were found in nutritional composition and mineral content between the chaya species, except minor differences in the relative composition of fatty acids, protein and amino acids. Cooking of chaya leaves slightly reduced nutritional composition of both chaya species. Cooking is essential prior to consumption to inactivate the toxic hydrocyanic glycosides present in chaya leaves. Based on the results of this study, the edible chaya leaves may be good dietary sources of minerals (Ca, K and Fe) and vitamins (ascorbic acid and beta-carotene).

Relationship between red cell membrane fatty acids and adipokines in individuals with varying insulin sensitivity.

PubMed

Min, Y; Lowy, C; Islam, S; Khan, F S; Swaminathan, R

2011-06-01

Plasma leptin and adiponectin, and membrane phospholipid fatty acid composition are implicated into the mechanism of insulin resistance but no clear pattern has emerged. Hence, this study examined these variables in subjects presenting to the diabetic clinic for a diagnostic glucose tolerance test. Body composition, glucose, glycated hemoglobin, insulin, leptin, adiponectin, and red cell and plasma phospholipid fatty acids were assessed from 42 normal and 28 impaired glucose tolerant subjects. Insulin sensitivity was determined by homeostatic model assessment. The plasma phosphatidylcholine fatty acid composition of the impaired glucose tolerant subjects was similar to that of normal subjects. However, the impaired glucose tolerant subjects had significantly lower linoleic (P<0.05), eicosapentaenoic (P<0.05) and docosahexaenoic (P<0.01) acids in the red cell phosphatidylcholine and phosphatidylethanolamine compared with the normal subjects. Moreover, red cell phosphatidylcholine docosahexaenoic acid correlated positively with adiponectin (r=0.290, P<0.05) but negatively with leptin (r=-0.252, P<0.05), insulin (r=-0.335, P<0.01) and insulin resistance (r=-0.322, P<0.01). Plasma triglycerides, leptin and glucose combined predicted about 60% of variation in insulin level whereas insulin was the only component that predicted the membrane fatty acids. We postulate that membrane phospholipids fatty acids have an indirect role in determining insulin concentration but insulin has a major role in determining membrane fatty acid composition.

3D composites based on the blends of chitosan and collagen with the addition of hyaluronic acid.

PubMed

Sionkowska, Alina; Kaczmarek, Beata; Lewandowska, Katarzyna; Grabska, Sylwia; Pokrywczyńska, Marta; Kloskowski, Tomasz; Drewa, Tomasz

2016-08-01

3D porous composites based on blends of chitosan, collagen and hyaluronic acid were obtained through the lyophilization process. Mechanical properties, swelling behavior and thermal stability of the blends were studied. Moreover, SEM images were taken and the structure of the blends was studied. Biological properties of the materials obtained were investigated by analyzing of proliferation rate of fibroblast cells incubated with biomaterial extract using MTT assay (3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide). The results showed that the properties of 3D composites based on the blends of chitosan and collagen were altered after the addition 1%, 2% and 5% of hyaluronic acid. Mechanical properties and thermal stability of chitosan/collagen blends were improved in the presence of hyaluronic acid in the composite. New 3D materials based on the blends of chitosan, collagen and hyaluronic acid were non-toxic and did not significantly affect cell morphology. Copyright © 2016 Elsevier B.V. All rights reserved.

Effect of sex and dietary fat intake on the fatty acid composition of phospholipids and triacylglycerol in rat heart

PubMed Central

Slater-Jefferies, Joanne L.; Hoile, Samuel P.; Lillycrop, Karen A.; Townsend, Paul A.; Hanson, Mark A.; Burdge, Graham C.

2010-01-01

Variations in the fatty acid composition of lipids in the heart alter its function and susceptibility to ischaemic injury. We investigated the effect of sex and dietary fat intake on the fatty acid composition of phospholipids and triacylglycerol in rat heart. Rats were fed either 40 or 100 g/kg fat (9:1 lard:soybean oil) from weaning until day 105. There were significant interactive effects of sex and fat intake on the proportions of fatty acids in heart phospholipids, dependent on phospholipid classes. 20:4n-6, but not 22:6n-3, was higher in phospholipids in females than males fed a low, but not a high, fat diet. There was no effect of sex on the composition of triacylglycerol. These findings suggest that sex is an important factor in determining the incorporation of dietary fatty acids into cardiac lipids. This may have implications for sex differences in susceptibility to heart disease. PMID:20719489