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Enrichment
Kinds of Enrichment Terms modified by Enrichment Selected AbstractsBENTHIC AND PLANKTONIC ALGAL COMMUNITIES IN A HIGH ARCTIC LAKE: PIGMENT STRUCTURE AND CONTRASTING RESPONSES TO NUTRIENT ENRICHMENT,JOURNAL OF PHYCOLOGY, Issue 6 2005Sylvia Bonilla We investigated the fine pigment structure and composition of phytoplankton and benthic cyanobacterial mats in Ward Hunt Lake at the northern limit of High Arctic Canada and the responses of these two communities to in situ nutrient enrichment. The HPLC analyses showed that more than 98% of the total pigment stocks occurred in the benthos. The phytoplankton contained Chrysophyceae, low concentrations of other protists and Cyanobacteria (notably picocyanobacteria), and the accessory pigments chl c2, fucoxanthin, diadinoxanthin, violaxanthin, and zeaxanthin. The benthic community contained the accessory pigments chl b, chl c2, and a set of carotenoids dominated by glycosidic xanthophylls, characteristic of filamentous cyanobacteria. The black surface layer of the mats was rich in the UV-screening compounds scytonemin, red scytonemin-like, and mycosporine-like amino acids, and the blue-green basal stratum contained high concentrations of light-harvesting pigments. In a first bioassay of the benthic mats, there was no significant photosynthetic or growth response to inorganic carbon or full nutrient enrichment over 15 days. This bioassay was repeated with increased replication and HPLC analysis in a subsequent season, and the results confirmed the lack of significant response to added nutrients. In contrast, the phytoplankton in samples from the overlying water column responded strongly to enrichment, and chl a biomass increased by a factor of 19.2 over 2 weeks. These results underscore the divergent ecophysiology of benthic versus planktonic communities in extreme latitudes and show that cold lake ecosystems can be dominated by benthic phototrophs that are nutrient sufficient despite their ultraoligotrophic overlying waters. [source] NITROGEN ENRICHMENT OF PORPHYRA PERFORATA THROUGH HIGH DOSE PULSE FERTILIZATIONJOURNAL OF PHYCOLOGY, Issue 2001Article first published online: 24 SEP 200 Zertuche-González, J. A1., Chanes-Miranda L2., Carmona, R3., Kraemer G4., Chopin T.5 & Yarish, C3 1Universidad Autonoma de Baja California, Instituto de Investigaciones Oceanologicas, PO Box #453, C.P. 22830, Ensenada, Baja California, Mexico. 2CBTIS-41, Km 115 Carretera Transpeninsular, Ensenada, BC Mexico. 3University of Connecticut, Department of Ecology and Evolutionary Biology, 1 University Place, Stamford, CT, 06901-2315, USA. 4State University of New York, Purchase College, Div. of Nat. Sciences, Purchase, NY, 10577, USA. 5University of New Brunswick, Centre for Coastal Studies and Aquaculture and Centre for Environmental and Molecular Algal Research, P.O. Box 5050, Saint John, New Brunswick, E2L 4L5, Canada Porphyra perforata is a highly preferred seaweed used as fodder in abalone culturing due to its relatively high nutritional value. High growth rates of abalone, particularly in the early stages, are suspected to be due the high protein-aminoacid and low water content of the Porphyra. Also, high NO3 content may be important to improve the bacterial flora in the animals, which in turn may favor more efficient digestion. Changes in the composition of Porphyra, however, can occur rapidly due to environmental conditions decreasing the nutritional value of the plant. Short term N pulse fertilization were performed on P. perforata in order to evaluate the feasibility to increase its nutritional value. Enrichment was performed under low light conditions (<5 ,E m -2 s -1) to inhibit growth and promote higher N enrichment per unit of biomass. Tissue N in the form of NO3, NH4 and total organic N were measured, after 3,6,12 and 24 hrs, in tissue exposed to 500 ,M of N. Results indicated a rapid N tissue enrichment particularly in the form of NO3. Nitrate accumulation occurs continuously, up to 24 hrs. Total organic N is maximum after 12 hrs and tends to decrease after that. Fertilization with NH4 promotes NO3 accumulation. These results suggest the feasibility to improve the nutritional value of P. perforata by short-term pulse fertilization. The capacity of this species to uptake NH4 under low light conditions (similar to those use in abalone culturing) makes it also ideal for integrated aquaculture. [source] A green light-absorbing phycoerythrin is present in the high-light-adapted marine cyanobacterium Prochlorococcus sp.ENVIRONMENTAL MICROBIOLOGY, Issue 10 2005Summary In the high-light-adapted unicellular marine cyanobacterium Prochlorococcus sp. MED4 the cpeB gene is the only gene coding for a structural phycobiliprotein. The absence of any other phycoerythrin gene in the fully sequenced genome of this organism, the previous inability to detect a gene product, and the mutation of two out of four cysteine residues, normally involved in binding chromophores, suggested that MED4- cpeB might not code for a functional protein. Here, transcription of MED4- cpeB at a low level was detected and the transcriptional start site was mapped. Enrichment of the protein identified phycoerythrobilin as its sole chromophore in vivo, which was confirmed by chromophorylation assays in vitro using the recombinant protein. Phycourobilin is the major chromophore in low-light-adapted Prochlorococcus ecotypes such as strain SS120. Therefore, spectrally tuned phycoerythrins are a characteristic feature of distinct Prochlorococcus ecotypes. Further in vitro mutagenesis experiments replacing one or both cysteines C61R/C82S by arginine or serine, respectively, revealed that only Cys82 is required for chromophore binding. Thus, an unusual green light-absorbing phycoerythrin evolved in the high-light-adapted ecotypes of Prochlorococcus, which potentially serves as a photoreceptor. [source] Toxicokinetics of perfluorocarboxylate isomers in rainbow troutENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 2 2009Amila O. De Silva Abstract Perfluorooctanoate (PFOA) and other perfluorocarboxylates (PFCAs) are widely dispersed in the environment. Current and/or historical production of PFOA and fluorochemical precursors was conducted by telomerization and electrochemical fluorination (ECF). Telomer products typically contain linear chains of perfluorocarbons, and ECF products are a mixture of linear and branched isomers. The objective of the present study was to examine the role of toxicokinetics on PFCA isomer profiles in fish since monitoring studies have revealed a predominance of n -isomers of PFCAs in biota. Using dietary exposure, rainbow trout were administered technical ECF PFOA isomers (6.9 ,g/kg/d), linear perfluorononanoate (1.4 ,g/kg/d n -PFNA), and isopropyl PFNA (1.1 ,g/kg/d iso -PFNA) for 36 d and then switched to a 40-d clean diet. Throughout exposure and depuration phases, blood and tissue sampling ensued. The accumulation ratio (AR) revealed similar accumulation propensity of n -PFOA and two minor branched PFOA isomers; however, the majority of branched isomers had lower AR values than n -PFOA. Enrichment of n -PFOA and n -PFNA relative to most branched isomers was consistent in all tissues. First-order elimination (kd) and half-life (t1/2) values were calculated. The largest t1/2 corresponded to n -PFNA followed by iso -PFNA. In ECF PFOA isomers, both n -PFOA and one minor branched isomer had the largest t1/2, suggesting that this minor isomer could be diagnostic of ECF exposure using environmental PFOA isomer patterns. Results of lower-dose ECF PFOA exposure showed similar results to the high-dose study; it is possible that both scenarios resulted in saturation of processes involved in PFCA transport. As such, the toxicokinetics of PFCA isomers at environmentally realistic levels may deviate from the results of the present study. [source] Enrichment of pomace olive oil in triterpenic acids during storage of "Alpeorujo" olive pasteEUROPEAN JOURNAL OF LIPID SCIENCE AND TECHNOLOGY, Issue 12 2008Aranzazu García Abstract Triterpenic acids are natural compounds present in plants and foods with beneficial properties for human health and thus they are desirable in the food, cosmetics and pharmaceutical industries. Pomace olive is considered a good source of these substances. In this study, oleanolic and maslinic acids were found to be the main triterpenic acids identified in pomace olive oil obtained from stored "Alpeorujo". Determination of the two acids was achieved by a new procedure that consists of extracting the acids from the oil with a mixture of methanol/ethanol, and then separating and quantifying them by HPLC. Results showed that their concentration increased up to 16,g/kg of oil during storage of the pomace in large ponds for 7,months. The concentration of both triterpenic acids was similar in the pomace olive oil obtained by using the centrifugation system. By contrast, a much lower concentration of maslinic than oleanolic acid was detected in pomace olive oils obtained by solvent extraction from the previously centrifugated "Alpeorujo" paste. These triterpenic acids also contributed to the acidity of the crude oil. Likewise, the oil of the pomace paste was enriched in other substances such as 4-ethylphenol and aliphatic alcohols during the storage of the paste in large ponds. Consequently, crude pomace olive oil can be considered a good source of triterpenic acids when obtained from a stored olive paste. [source] Docosahexaenoic acid stabilizes soluble amyloid-, protofibrils and sustains amyloid-,-induced neurotoxicity in vitroFEBS JOURNAL, Issue 4 2007Ann-Sofi Johansson Enrichment of diet and culture media with the polyunsaturated fatty acid docosahexaenoic acid has been found to reduce the amyloid burden in mice and lower amyloid-, (A,) levels in both mice and cultured cells. However, the direct interaction of polyunsaturated fatty acids, such as docosahexaenoic acid, with A,, and their effect on A, aggregation has not been explored in detail. Therefore, we have investigated the effect of docosahexaenoic acid, arachidonic acid and the saturated fatty acid arachidic acid on monomer oligomerization into protofibrils and protofibril fibrillization into fibrils in vitro, using size exclusion chromatography. The polyunsaturated fatty acids docosahexaenoic acid and arachidonic acid at micellar concentrations stabilized soluble A,42 wild-type protofibrils, thereby hindering their conversion to insoluble fibrils. As a consequence, docosahexaenoic acid sustained amyloid-,-induced toxicity in PC12 cells over time, whereas A, without docosahexaenoic acid stabilization resulted in reduced toxicity, as A, formed fibrils. Arachidic acid had no effect on A, aggregation, and neither of the fatty acids had any protofibril-stabilizing effect on A,42 harboring the Arctic mutation (A,E22G). Consequently, A,Arctic-induced toxicity could not be sustained using docosahexaenoic acid. These results provide new insights into the toxicity of different A, aggregates and how endogenous lipids can affect A, aggregation. [source] Sterol-induced upregulation of phosphatidylcholine synthesis in cultured fibroblasts is affected by the double-bond position in the sterol tetracyclic ring structureFEBS JOURNAL, Issue 21 2000Petra Leppimäki We have examined how a specific enrichment of cultured fibroblasts with various sterols (cholesterol, lathosterol, 7-dehydrocholesterol, allocholesterol and dihydrocholesterol) regulate synthesis de novo of phosphatidylcholine, cholesterol and cholesteryl (or steryl) esters in human skin fibroblasts. When human skin fibroblasts were incubated for 1 h with 130 µm cholesterol/CyD complexes, the mass of cellular free cholesterol increased by 100 nmol·mg,1 protein (from 90 nmol·mg,1 to 190 nmol·mg,1 protein). A similar exposure of cells to different sterol/CyD complexes increased the cell sterol content between 38 and 181 nmol sterol per mg cell protein. In cholesterol-enriched cells, the rate of phosphatidylcholine synthesis was doubled compared to control cells, irrespective of the type of precursor used ([3H]choline, [3H]palmitic acid, or [14C]glycerol). Enrichment of fibroblasts with 7-dehydrocholesterol, allocholesterol, or dihydrocholesterol also upregulated phosphatidylcholine synthesis, whereas cells enriched with lathosterol failed to upregulate their phosphatidylcholine synthesis. The activity of membrane-bound CTP:phosphocholine cytidylyltransferase, the rate-limiting enzyme, was increased by 47 ± 4% in cholesterol-enriched cells whereas its activity was unchanged in lathosterol-enriched cells. Sterol enrichment with all tested sterols (including lathosterol) down-regulated acetate-incorporation into cholesterol, and upregulated sterol esterification in the sterol-enriched fibroblasts. Using 31P-NMR to measure the lamellar-to-hexagonal (L,,HII) phase transition in multilamellar lipid dispersions, lathosterol-containing membranes underwent their transition at significantly higher temperatures compared to membranes containing any of the other sterols. In a system with 1-palmitoyl-2-oleoyl- sn -glycero-3-phosphoethanolamine and either cholesterol or lathosterol (70 : 30 mol/mol), differential scanning calorimetry also revealed that the L,,HII -transition occurred at a higher temperature with lathosterol compared to either cholesterol, allocholesterol, or dihydrocholesterol. These findings together suggest that there may exist a correlation between the propensity of a sterol to stabilize the L,,HII -transition and its capacity to upregulate the activity of CTP:phosphocholine cytidylyltransferase in cells. [source] Growth kinetics of microorganisms isolated from Alaskan soil and permafrost in solid media frozen down to ,35°CFEMS MICROBIOLOGY ECOLOGY, Issue 2 2007Nicolai S. Panikov Abstract We developed a procedure to culture microorganisms below freezing point on solid media (cellulose powder or plastic film) with ethanol as the sole carbon source without using artificial antifreezes. Enrichment from soil and permafrost obtained on such frozen solid media contained mainly fungi, and further purification resulted in isolation of basidiomycetous yeasts of the genera Mrakia and Leucosporidium as well as ascomycetous fungi of the genus Geomyces. Contrary to solid frozen media, the enrichment of liquid nutrient solutions at 0°C or supercooled solutions stabilized by glycerol at ,1 to ,5°C led to the isolation of bacteria representing the genera Polaromonas, Pseudomonas and Arthrobacter. The growth of fungi on ethanol,microcrystalline cellulose media at ,8°C was exponential with generation times of 4.6,34 days, while bacteria displayed a linear or progressively declining curvilinear dynamic. At ,17 to ,0°C the growth of isolates and entire soil community on 14C-ethanol was continuous and characterized by yields of 0.27,0.52 g cell C (g of C-substrate),1, similar to growth above the freezing point. The ,state of maintenance,' implying measurable catabolic activity of non-growing cells, was not confirmed. Below ,18 to ,35°C, the isolated organisms were able to grow only transiently for 3 weeks after cooling with measurable respiratory and biosynthetic (14CO2 uptake) activity. Then metabolic activity declined to zero, and microorganisms entered a state of reversible dormancy. [source] Structure and activity of the nitrate-reducing community in the rhizosphere of Lolium perenne and Trifolium repens under long-term elevated atmospheric pCO2FEMS MICROBIOLOGY ECOLOGY, Issue 3 2004Kathrin Deiglmayr Abstract Rhizosphere soil was sampled in monocultures of Lolium perenne and Trifolium repens in June and October 2002, at two different nitrogen fertilisation levels (14 and 56 g N m,2 year,1) and under two pCO2 atmospheres (360 and 600 ppmv) at the Swiss FACE (Free Air Carbon dioxide Enrichment) site. Directly extracted soil DNA was analysed with restriction fragment length polymorphism (PCR-RFLP) by use of degenerated primers for the narG gene encoding the active site of the membrane-bound nitrate reductase. The corresponding enzyme activity of the nitrate reductase was determined colorimetrically after 24 h of anaerobic incubation. The narG PCR-RFLP fingerprints showed that the structure of the nitrate-reducing community was primarily affected by season and pH of the sampling site, whereas CO2 enrichment, plant species or fertiliser treatment had no apparent effect. In contrast, the nitrate reductase activity responded to N fertilisation, CO2 enrichment and plant species in October, whereas in June drought stress most likely kept the enzyme activity at a low level in all treatments. Apparently, the respiratory nitrate-reducing community adapted to different treatments primarily by altered enzyme activity. [source] Characterization of the major odorants found in the peel oil of Citrus reticulata Blanco cv. Clementine using gas chromatography,olfactometryFLAVOUR AND FRAGRANCE JOURNAL, Issue 4 2003Mary G. Chisholm Abstract Gas chromatography,olfactometry (GC,O), gas chromatography,mass spectrometry (GC,MS) and preparative column chromatography were used to identify the key odorants present in laboratory-extracted clementine oil from Spain. Almost 50 odorants were identi,ed using GC,O, many of which were unsaturated aldehydes with high odour spectrum values (OSV). , - and , -sinensal, trans -4,5-epoxy-(E)-2-decanal, (E,Z)-2,6-dodecadienal and linalool were found to dominate clementine oil aroma. Enrichment of the oxygenates using preparative column chromatography provided further identi,cation of a total of 50 aldehydes, not all of which were present in the oil at concentrations high enough to produce a response using GC,O. Aldehydes contributed approximately 80% of the total aroma of clementine oil. New odorants not previously reported in clementine oil include many unsaturated aldehydes, trans -4,5-epoxy-(E)-2-decenal, trans -4,5-epoxy-(E)-2-dodecenal, 4-hydroxy-2,5-dimethyl-3(2H)-furanone (furaneol), 3-hydroxy-4,5-dimethyl-3(2H)-furanone (sotolon) and 1,8-cineole. No single odorant emerged as being characteristic of clementine oil aroma. Copyright © 2003 John Wiley & Sons, Ltd. [source] Sequestration and turnover of plant- and microbially derived sugars in a temperate grassland soil during 7 years exposed to elevated atmospheric pCO2GLOBAL CHANGE BIOLOGY, Issue 2 2007MICHAEL BOCK Abstract Temperate grasslands contribute about 20% to the global terrestrial carbon (C) budget with sugars contributing 10,50% to this soil C pool. Whether the observed increase of the atmospheric CO2 concentration (pCO2) leads to additional C sequestration into these ecosystems or enhanced mineralization of soil organic matter (SOM) is still unclear. Therefore, the aim of the presented study was to investigate the impact of elevated atmospheric pCO2 on C sequestration and turnover of plant- (arabinose and xylose) and microbially derived (fucose, rhamnose, galactose, mannose) sugars in soil, representing a labile SOM pool. The study was carried out at the Swiss Free Air Carbon Dioxide Enrichment (FACE) experiment near Zurich. For 7 years, Lolium perenne swards were exposed to ambient and elevated pCO2 (36 and 60 Pa, respectively). The additional CO2 in the FACE plots was depleted in 13C compared with ambient plots, so that ,new' (<7 years) C inputs could be determined by means of compound-specific stable isotope analysis (13C : 12C). Samples were fractionated into clay, silt, fine sand and coarse sand, which yielded relatively stable and labile SOM pools with different turnover rates. Total sugar sequestration into bulk soil after 7 years of exposure to elevated pCO2 was about 28% compared with the control plots. In both ambient and elevated plots, total sugar concentrations in particle size fractions increased in the order sand Evaluation of in silico splice tools for decision-making in molecular diagnosis,HUMAN MUTATION, Issue 7 2008Claude Houdayer Abstract It appears that all types of genomic nucleotide variations can be deleterious by affecting normal pre-mRNA splicing via disruption/creation of splice site consensus sequences. As it is neither pertinent nor realistic to perform functional testing for all of these variants, it is important to identify those that could lead to a splice defect in order to restrict transcript analyses to the most appropriate cases. Web-based tools designed to provide such predictions are available. We evaluated the performance of six of these tools (Splice Site Prediction by Neural Network [NNSplice], Splice-Site Finder [SSF], MaxEntScan [MES], Automated Splice-Site Analyses [ASSA], Exonic Splicing Enhancer [ESE] Finder, and Relative Enhancer and Silencer Classification by Unanimous Enrichment [RESCUE]-ESE) using 39 unrelated retinoblastoma patients carrying different RB1 variants (31 intronic and eight exonic). These 39 patients were screened for abnormal splicing using puromycin-treated cell lines and the results were compared to the predictions. As expected, 17 variants impacting canonical AG/GT splice sites were correctly predicted as deleterious. A total of 22 variations occurring at loosely defined positions (±60 nucleotides from an AG/GT site) led to a splice defect in 19 cases and 16 of them were classified as deleterious by at least one tool (84% sensitivity). In other words, three variants escaped in silico detection and the remaining three were correctly predicted as neutral. Overall our results suggest that a combination of complementary in silico tools is necessary to guide molecular geneticists (balance between the time and cost required by RNA analysis and the risk of missing a deleterious mutation) because the weaknesses of one in silico tool may be overcome by the results of another tool. Hum Mutat 29(7), 975,982, 2008. © 2008 Wiley-Liss, Inc. [source] A Facile Synthesis Approach to C8 -Functionalized Magnetic Carbonaceous Polysaccharide Microspheres for the Highly Efficient and Rapid Enrichment of Peptides and Direct MALDI-TOF-MS AnalysisADVANCED MATERIALS, Issue 21 2009Hemei Chen Biocompatible C8 -functionalized magnetic carbonaceous polysaccharide microspheres are synthesized via a facile, low-cost, and large-scale route, and their use for the enrichment of peptides from protein digest mixtures is presented. The process of enrichment is very simple, quick, and efficient. Peptides loaded onto the C8 -functionalized magnetic carbonaceous polysaccharide microspheres can be directly analyzed by MALDI-TOF-MS without prior elution from the microspheres. [source] Isolation of microsatellite loci in the pollinating fig wasp of Ficus hispida, Ceratosolen solmsiINSECT SCIENCE, Issue 4 2008Hao Yu Abstract Microsatellite loci were isolated for Ceratosolen solmsi, pollinator of the dioecious Ficus hispida. We developed nine polymorphic microsatellite loci based on the method of polymerase chain reaction isolation of microsatellite arrays (PIMA). Enrichment of genomic libraries was performed by random amplified polymorphic DNA (RAPD). A subset of 38 positive clones was sequenced; 15 clones showed microsatellite loci. We tested 15 designed primer pairs and nine of them produced polymorphic amplification in 48 individual wasps collected from different fruits of the dioecious host fig Ficus hispida in China. Among the 48 individuals, 49 alleles were obtained at the nine loci. The observed heterozygosity ranged between 0.357 and 0.634. [source] Enrichment of enhanced assumed strain approximations for representing strong discontinuities: addressing volumetric incompressibility and the discontinuous patch testINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 1 2004J. E. Dolbow Abstract We present a geometrically non-linear assumed strain method that allows for the presence of arbitrary, intra-finite element discontinuities in the deformation map. Special attention is placed on the coarse-mesh accuracy of these methods and their ability to avoid mesh locking in the incompressible limit. Given an underlying mesh and an arbitrary failure surface, we first construct an enriched approximation for the deformation map with the non-linear analogue of the extended finite element method (X-FEM). With regard to the richer space of functions spanned by the gradient of the enriched approximation, we then adopt a broader interpretation of variational consistency for the construction of the enhanced strain. In particular, in those elements intersected by the failure surface, we construct enhanced strain approximations which are orthogonal to piecewise-constant stress fields. Contrast is drawn with existing strong discontinuity approaches where the enhanced strain variations in localized elements were constructed to be orthogonal to constant nominal stress fields. Importantly, the present formulation gives rise to a symmetric tangent stiffness matrix, even in localized elements. The present modification also allows for the satisfaction of a discontinuous patch test, wherein two different constant stress fields (on each side of the failure surface) lie in the solution space. We demonstrate how the proposed modifications eliminate spurious stress oscillations along the failure surface, particularly for nearly incompressible material response. Additional numerical examples are provided to illustrate the efficacy of the modified method for problems in hyperelastic fracture mechanics. Copyright © 2003 John Wiley & Sons, Ltd. [source] Enrichment and transplantation of spermatogonial stem cellsINTERNATIONAL JOURNAL OF ANDROLOGY, Issue S2 2000Takashi Shinohara Spermatogenesis is a complex, highly organized process originated from stem cell spermatogonia. Because there are very few stem cells and they can only be defined by their function, the identification and isolation of these cells has been very difficult. By using a spermatogonial transplantation assay system, we have identified ,6 -and ,1 -integrin expression on stem cells, and cells isolated with these antigens were significantly enriched in stem cells. This is the first demonstration of spermatogonial stem cell-associated antigens. Analysis of two infertile mouse models, Steel/SteelDickie (Sl/Sld) and experimental cryptorchidism, showed that the number of stem cells is reduced in Sl/Sld testis. Whereas cryptorchid testes are greatly enriched for stem cells, and one in 200 cells is a stem cell. These techniques will provide an important starting point for further purification and characterization of spermatogonial stem cells. [source] Degradation of naphthenic acids by sediment micro-organismsJOURNAL OF APPLIED MICROBIOLOGY, Issue 5 2006L.F. Del Rio Abstract Aims:, Naphthenic acids (NAs) are naturally occurring, linear and cyclic carboxylic surfactants associated with the acidic fraction of petroleum. NAs account for most of the acute aquatic toxicity of oil sands process-affected water (OSPW). The toxicity of OSPW can be reduced by microbial degradation. The aim of this research was to determine the extent of NA degradation by sediment microbial communities exposed to varying amounts of OSPW. Methods and Results:, Eleven wetlands, both natural and process-affected, and one tailings settling pond in Northern Alberta were studied. The natural wetlands and process-affected sites fell into two distinct groups based on their water chemistry. The extent of degradation of a 14C-labelled monocyclic NA surrogate [14C-cyclohexane carboxylic acid (CCA)] was relatively uniform in all sediments (approximately 30%) after 14 days. In contrast, degradation of a bicyclic NA surrogate [14C-decahydronaphthoic acid (DHNA)]was significantly lower in non process-affected sediments. Enrichment cultures, obtained from an active tailings settling pond, using commercially available NAs as the sole carbon source, resulted in the isolation of a co-culture containing Pseudomonas putida and Pseudomonas fluorescens. Quantitative GC,MS analysis showed that the co-culture removed >95% of the commercial NAs, and partially degraded the process NAs from OSPW with a resulting NA profile similar to that from ,aged wetlands'. Conclusions:, Exposure to NAs induced and/or selected micro-organisms capable of more effectively degrading bicyclic NAs. Native Pseudomonas spp. extensively degraded fresh, commercial NA. The recalcitrant NAs resembled those found in process-affected wetlands. Significance and Impact of the Study:, These results suggest that it may be possible to manipulate the existing environmental conditions to select for a microbial community exhibiting higher rates of NA degradation. This will have significant impact on the design of artificial wetlands for water treatment. [source] Enrichment and identification of bacteria capable of reducing chemical oxygen demand of anaerobically treated molasses spent washJOURNAL OF APPLIED MICROBIOLOGY, Issue 6 2004M. Ghosh Abstract Aims:, The aim of this study was to isolate and identify bacterial strains capable of using recalcitrant compounds of molasses spent wash as sole carbon source from the soils of abandoned sites of distillery effluent discharge and characterize their ability of reducing the chemical oxygen demand (COD) of the spent wash. Methods and Results:, The isolates were grouped into six haplotypes by amplified ribosomal DNA restriction analysis (ARDRA) and BOX-PCR. The phylogenetic position of the representatives of the six main haplotypes strains was determined by 16S rDNA sequencing. They showed maximum similarity to six genera viz. Pseudomonas, Enterobacter, Stenotrophomonas, Aeromonas, Acinetobacter and Klebsiella. The extent of COD (44%) reduced collectively by the six strains was equal to that reduced individually by Aeromonas, Acinetobacter, Pseudomonas and Enterobacter. With spent wash as sole carbon source, the COD reducing strains grew faster at 37°C than 30°C. Conclusions:, Bacterial strains capable of degrading some of the recalcitrant compounds of anaerobically digested molasses spent wash can be isolated from the soils of abandoned sites of distillery effluent discharge. Biostimulation of these bacteria, which can degrade 44% of the carbon compounds of anaerobically digested molasses spent wash can be achieved by nitrogen fertilization and relatively higher temperature. Significance and Impact of the Study:, Supplementation of nitrogen source and controlling the temperature can be used in evolving strategies for in situ bioremediation of anaerobically digested spent wash from distilleries. [source] Rapid and effective detection of anthrax spores in soil by PCRJOURNAL OF APPLIED MICROBIOLOGY, Issue 4 2003H.I. Cheun Abstract Aims: To detect Bacillus anthracis DNA from soil using rapid and simple procedures. Methods and Results: Various amounts of B. anthracis Pasteur II spores were added artificially to 1 g of soil, which was then washed with ethanol and sterile water. Enrichment of the samples in trypticase soy broth was performed twice. A DNA template was prepared from the second enrichment culture using a FastPrep instrument. The template was then used for nested and real-time polymerase chain reaction (PCR) with B. anthracis -specific primers, to confirm the presence of B. anthracis chromosomal DNA and the pXO1/pXO2 plasmids. Conclusions: One cell of B. anthracis in 1 g of soil could be detected by nested and real-time PCR. The usefulness of the PCR method using field samples was also confirmed. Significance and Impact of the Study: The results indicate that this could be a useful method for detecting anthrax-spore contaminated soil with high sensitivity. Its application could have great impact on the progress of epidemiological surveillance. [source] A subpopulation of mesenchymal stromal cells with high osteogenic potentialJOURNAL OF CELLULAR AND MOLECULAR MEDICINE, Issue 8b 2009Hua Liu Abstract Current bone disease therapy with bone marrow-derived mesenchymal stromal cells (MSC) is hampered by low efficiency. Advanced allogeneic studies on well-established mouse genetic and disease models are hindered by difficulties in isolating murine MSC (mMSC). And mMSC prepared from different laboratories exhibit significant heterogeneity. Hence, this study aimed to identify and isolate a sub-population of mMSC at an early passage number with high osteogenic potential. Enrichment of mMSC was achieved by 1-hr silica incubation and negative selection. Approximately 96% of these cells synthesized osteocalcin after 28 days of osteogenic induction in vitro, and displayed a complete dynamic alteration of alkaline phosphatase (ALP) activity with increasing osteogenic maturation and strong mineralization. Moreover, the cells displayed uniform and stable surface molecular profile, long-term survival, fast proliferation in vitro with maintenance of normal karyotype and distinct immunological properties. CD73 was found to be expressed exclusively in osteogenesis but not in adipogenesis. These cells also retained high osteogenic potential upon allogeneic transplantation in an ectopic site by the detection of bone-specific ALP, osteopontin, osteocalcin and local mineralization as early as 12 days after implantation. Hence, these cells may provide a useful source for improving current strategies in bone regenerative therapy, and for characterizing markers defining the putative MSC population. [source] Storage of biodegradable polymers by an enriched microbial community in a sequencing batch reactor operated at high organic load rateJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 11 2005Davide Dionisi Abstract The production of polyhydroxyalkanoates (PHAs) from organic acids by mixed bacterial cultures using a process based on aerobic enrichment of activated sludge, that selects for mixed microbial cultures able to store PHAs at high rates and yields, is described. Enrichment resulted from the selective pressure established by periodic feeding the carbon source in a sequencing batch reactor (SBR); a mixture of acetic, lactic and propionic acids was fed at high frequency (2 hourly), high dilution rate (1 d,1), and at high organic load rate (12.75 g chemical oxygen demand (COD) L,1 d,1). The performance of the SBR was assessed by microbial biomass and PHA production as well as the composition and polymer content of the biomass. A final batch stage was used to increase the polymer concentration of the excess sludge produced in the SBR and in which the behaviour of the biomass was investigated by determining PHA production rates and yields. The microbial biomass selected in the SBR produced PHAs at high rate [278 mg PHAs (as COD) g biomass (as COD),1 h,1, with a yield of 0.39 mg PHAs (as COD) mg removed substrates (as COD),1], reaching a polymer content higher than 50% (on a COD basis). The stored polymer was the copolymer poly(3-hydroxybutyrate/3-hydroxyvalerate) [P(HB/HV)], with an HV fraction of 18% mol mol,1. The microbial community selected in the SBR was analysed by DGGE (denaturing gradient gel electrophoresis). The operating conditions of the SBR were shown to select for a restricted microbial population which appeared quite different in terms of composition with respect to the initial microbial cenosis in the activated sludge used as inoculum. On the basis of the sequencing of the major bands in the DGGE profiles, four main genera were identified: a Methylobacteriaceae bacterium, Flavobacterium sp, Candidatus Meganema perideroedes, and Thauera sp. The effects of nitrogen depletion (ie absence of growth) and pH variation were also investigated in the batch stage and compared with the SBR operative mode. Absence of growth did not stimulate higher PHA production, so indicating that the periodic feed regime fully exploited the storage potential of the enriched culture. Polymer production rates remained high between pH 6.5 and 9.5, whereas the HV content in the stored polymer strongly increased as the pH value increased. This study shows that polymer composition in the final batch stage can readily be controlled independently from the feed composition in the SBR. Copyright © 2005 Society of Chemical Industry [source] Cordia millenii: on the risk of local extinction?AFRICAN JOURNAL OF ECOLOGY, Issue 3 2009Fred Babweteera Abstract Selective logging of valuable tropical timber trees is a conservation concern because it threatens the long-term sustainability of forests. However, there is insufficient information regarding the postlogging recovery of harvested species. Here, I assessed the seed dispersal patterns, recruitment and abundance of Cordia millenii, a valuable timber tree in two Ugandan tropical rain forests that have been subjected to varying disturbance regimes. The aim was to determine the vulnerability of Cordia in these forests. The rate of seed dispersal was lower in the heavily disturbed Mabira Forest compared with the less disturbed Budongo Forest. Frugivores in Mabira were small-bodied individuals that spat seeds beneath fruiting trees, whereas 90% of the fruit in Budongo was consumed by large-bodied chimpanzees that disperse seeds over long distances. Juveniles of Cordia were not found in the closed forest, although they were found in forest gaps in Budongo but not Mabira. Mature tree density was higher in Budongo compared with Mabira. Lack of effective seed dispersal coupled with the inability of seedlings of Cordia to establish under closed canopy account for the arrested recruitment in Mabira. Enrichment planting in felling gaps is necessary to avoid local extinction of Cordia in forests without large vertebrates. Résumé L'abattage sélectif des espèces précieuses d'arbres tropicaux inquiète le milieu de la conservation parce qu'il menace la durabilité des forêts à long terme. Cependant, il n'y a pas assez d'informations au sujet de la restauration des espèces prélevées après l'abattage. Ici, j'ai évalué les schémas de dispersion des semences, le recrutement et l'abondance de Cordia millenii, une espèce d'arbre prisée, dans deux forêts tropicales pluviales d'Ouganda qui ont été soumises à des régimes de perturbation variables. Le but était de déterminer la vulnérabilité de Cordia dans ces forêts. Le taux de dispersion des graines était plus faible dans la forêt très perturbée de Mabira que dans la forêt de Budongo, moins dérangée. Les frugivores de Mabira étaient des individus de petite taille qui recrachaient les graines sous les arbres producteurs des fruits alors que 90% des fruits de Budongo étaient consommés par des chimpanzés qui peuvent disperser les semences sur le longues distances. On n'a pas trouvé de juvénile de Cordia dans la forêt fermée; on en trouvait dans des clairières dans la forêt de Budongo, mais pas dans celle de Mabira. La densité des arbres matures était plus haute à Budongo qu'à Mabira. Le manque de dispersion efficace des graines, coupléà l'incapacité des semences de Cordia de s'établir sous une canopée fermée, intervient dans l'arrêt du recrutement à Mabira. Il est nécessaire de pratiquer un enrichissement des plantations dans les clairières déboisées pour éviter l'extinction locale des Cordia dans les forêts qui n'abritent pas de grands vertébrés. [source] Effects of genotype, elevated CO2 and elevated O3 on aspen phytochemistry and aspen leaf beetle Chrysomela crotchi performanceAGRICULTURAL AND FOREST ENTOMOLOGY, Issue 3 2010Leanne M. Vigue 1Trembling aspen Populus tremuloides Michaux is an important forest species in the Great Lakes region and displays tremendous genetic variation in foliar chemistry. Elevated carbon dioxide (CO2) and ozone (O3) may also influence phytochemistry and thereby alter the performance of insect herbivores such as the aspen leaf beetle Chrysomela crotchi Brown. 2The present study aimed to relate genetic- and atmospheric-based variation in aspen phytochemistry to C. crotchi performance (larval development time, adult mass, survivorship). The experiment was conducted at the Aspen Free-Air CO2 Enrichment (FACE) site in northern Wisconsin. Beetles were reared on three aspen genotypes under elevated CO2 and/or O3. Leaves were collected to determine chemical characteristics. 3The foliage exhibited significant variation in nitrogen, condensed tannins and phenolic glycosides among genotypes. CO2 and O3, however, had little effect on phytochemistry. Nonetheless, elevated CO2 decreased beetle performance on one aspen genotype and had inconsistent effects on beetles reared on two other genotypes. Elevated O3 decreased beetle performance, especially for beetles reared on an O3 -sensitive genotype. Regression analyses indicated that phenolic glycosides and nitrogen explain a substantial amount (27,45%) of the variation in herbivore performance. 4By contrast to the negative effects that are typically observed with generalist herbivores, aspen leaf beetles appear to benefit from phenolic glycosides, chemical components that are largely genetically-determined in aspen. The results obtained in the present study indicate that host genetic variation and atmospheric concentrations of greenhouse gases will be important factors in the performance of specialist herbivores, such as C. crotchi, in future climates. [source] Performance of the invasive weevil Polydrusus sericeus is influenced by atmospheric CO2 and host speciesAGRICULTURAL AND FOREST ENTOMOLOGY, Issue 3 2010Michael L. Hillstrom 1Natural forest systems constitute a major portion of the world's land area, and are subject to the potentially negative effects of both global climate change and invasion by exotic insects. A suite of invasive weevils has become established in the northern hardwood forests of North America. How these insects will respond to increasing CO2 or O3 is unknown. 2The present study examined the effects of elevated atmospheric CO2 and O3 on the invasive weevil Polydrusus sericeus Schaller at the Aspen Free Air CO2 Enrichment (FACE) site near Rhinelander, Wisconsin. A performance assay was conducted in the laboratory during the summer of 2007 using mated pairs of P. sericeus fed a combination of aspen, birch and maple foliage. We recorded leaf area consumption, oviposition and adult longevity. We also conducted visual abundance surveys in the field from 2004 to 2007 on aspen and birch at Aspen FACE. 3Elevated CO2, but not O3, significantly affected P. sericeus performance. Female, but not male, longevity was reduced under elevated CO2. Polydrusus sericeus also produced fewer eggs under elevated CO2 conditions compared with ambient conditions. Adult P. sericeus strongly preferred birch over both aspen and maple, regardless of fumigation treatment. 4The effects of elevated CO2 on P. sericeus populations at Aspen FACE were minimal, and varied among years and host tree species. Polydrusus sericeus abundance was significantly greater on birch than aspen. Over the long term, elevated CO2 may reduce adult female longevity and fecundity of P. sericeus. Further studies are needed to evaluate how this information may scale to ecosystem impacts. [source] Individual growth rates do not predict aphid population densities under altered atmospheric conditionsAGRICULTURAL AND FOREST ENTOMOLOGY, Issue 3 2010Edward B. Mondor 1Altered atmospheric composition, associated with climate change, can modify herbivore population dynamics through CO2 and/or O3 -mediated changes in plant quality. 2Although pea aphid Acyrthosiphon pisum genotypes exhibit intraspecific variation in population growth in response to atmospheric composition, the proximate mechanisms underlying this variation are largely unknown. 3By rearing single (green, pink) and mixed (green + pink) pea aphid genotypes on red clover Trifolium pratense at the Aspen Free Air CO2 and O3 Enrichment (Aspen FACE) site, we assessed whether: (i) elevated CO2 and/or O3 concentrations alter aphid growth and development and (ii) individual aphid growth rates predict aphid population densities. 4We showed that growth and development of individual green and pink aphids were not influenced by CO2 and/or O3 concentrations when reared as individual or mixed genotypes. Individual growth rates, however, did not predict population densities. 5Reared as a single genotype, green pea aphid populations decreased in response to elevated CO2 concentrations, but not in response to elevated CO2 + O3 concentrations. Pink pea aphid populations reared as a single genotype were unaffected by augmented CO2 or O3. Populations of mixed genotypes, however, were reduced under elevated CO2 concentrations, irrespective of O3 concentrations. 6Herbivore population sizes may not readily be predicted from growth rates of individual organisms under atmospheric conditions associated with global climate change. [source] The Effect of Feeding Enrichment upon Reported Working Ability and Behavior of Kenneled Working DogsJOURNAL OF FORENSIC SCIENCES, Issue 6 2008Samantha A. Gaines Ph.D. Abstract:, It is widely recommended that kenneled dogs are provided with environmental enrichment such as toys or feeding devices. However, the adoption of enrichment for military working dogs is impeded by a widespread belief that it reduces their motivation to work. Handlers of 22 working German Shepherd dogs were asked to rate their dogs on 11 attributes pertaining to working ability, related behavioral traits, and health. Eight of the dogs were then provided with daily feeding enrichment for 4 months, while the remainder were given equivalent human attention. The same 11 traits were scored again following the enrichment period: 10 changed little over the period while handlers' reports of their dogs'Ability to learn from being rewarded increased significantly. Changes for all attributes were virtually identical in enriched and control dogs. We conclude that if correctly managed, feeding enrichment can be introduced to kenneled working dogs without any reported detrimental effects upon working ability, health, or behavior. [source] Response of quaking aspen genotypes to enriched CO2: foliar chemistry and tussock moth performanceAGRICULTURAL AND FOREST ENTOMOLOGY, Issue 4 2002Richard L. Lindroth Abstract 1Genetic variation in the phytochemical responses of plants to CO2 enrichment is likely to alter trophic dynamics, and to shift intraspecific selection pressures on plant populations. We evaluated the independent and interactive effects of atmospheric CO2 and quaking aspen (Populus tremuloides Michx.) genotype on chemical composition of foliage and performance of the whitemarked tussock moth (Orgyia leucostigma J. E. Sm.). 2This research was conducted at the Aspen FACE (Free Air CO2 Enrichment) site in northern Wisconsin, U.S.A. Leaf samples were collected periodically from each of three genetically variable aspen genotypes growing under ambient and elevated CO2, and analysed for levels of primary and secondary metabolites. Tussock moth larvae were reared in situ on experimental trees, and development times and pupal masses were recorded. 3Foliar chemical composition varied among aspen genotypes and in response to CO2 enrichment. However, chemical responses of trees to elevated CO2 were generally consistent across genotypes. 4Larval development times varied among host genotypes and increased slightly for insects on high-CO2 plants. Enriched CO2 tended to reduce insect pupal masses, particularly for females on one of the three aspen genotypes. 5CO2 × genotype interactions observed for plant chemistry and insect performance in this study with a small number of genotypes are probably too few, and too weak, to shift selection pressures in aspen populations. These results differ, however, from earlier work in which more substantial CO2 × genotype interactions were observed for plant chemistry. [source] Enrichment of HFE mutations in Swedish patients with familial and sporadic form of porphyria cutanea tardaJOURNAL OF INTERNAL MEDICINE, Issue 6 2004P. Harper First page of article [source] Effect of Environmental Enrichment on Stress Related Systems in RatsJOURNAL OF NEUROENDOCRINOLOGY, Issue 5 2004F. Moncek Abstract The aim of this study was to test whether environmental enrichment alters the status and responsiveness of pituitary-adrenocortical and sympathetic-adrenomedullary hormones in rats. Previous studies have shown that rats kept in an enriched environment differ from those kept in standard cages in dendritic branching, synaptogenesis, memory function, emotionality and behaviour. In male Wistar rats kept in an enriched environment for 40 days, we studied basal concentrations of hormones, endocrine responses to 5-HT1A challenge and responsiveness and adaptation to repeated handling. Environmental enrichment consisted of large plexiglass cages with 10 rats per cage, which contained variety of objects exchanged three times a week. Rats kept in this enriched environment had higher resting plasma concentrations of corticosterone, larger adrenals and increased corticosterone release to buspirone challenge compared to controls. Lower adrenocorticotropic hormone, corticosterone and adrenaline responses to handling were noticed in rats kept in an enriched environment. Exposure to repeated handling led to a more rapid extinction of corticosterone responses in rats kept in an enriched environment. Thus, environmental enrichment leads to pronounced changes in neuroendocrine regulation, including larger adrenals and increased adrenocortical function, which are so far considered to be indication of chronic stress. [source] NITROGEN ENRICHMENT OF PORPHYRA PERFORATA THROUGH HIGH DOSE PULSE FERTILIZATIONJOURNAL OF PHYCOLOGY, Issue 2001Article first published online: 24 SEP 200 Zertuche-González, J. A1., Chanes-Miranda L2., Carmona, R3., Kraemer G4., Chopin T.5 & Yarish, C3 1Universidad Autonoma de Baja California, Instituto de Investigaciones Oceanologicas, PO Box #453, C.P. 22830, Ensenada, Baja California, Mexico. 2CBTIS-41, Km 115 Carretera Transpeninsular, Ensenada, BC Mexico. 3University of Connecticut, Department of Ecology and Evolutionary Biology, 1 University Place, Stamford, CT, 06901-2315, USA. 4State University of New York, Purchase College, Div. of Nat. Sciences, Purchase, NY, 10577, USA. 5University of New Brunswick, Centre for Coastal Studies and Aquaculture and Centre for Environmental and Molecular Algal Research, P.O. Box 5050, Saint John, New Brunswick, E2L 4L5, Canada Porphyra perforata is a highly preferred seaweed used as fodder in abalone culturing due to its relatively high nutritional value. High growth rates of abalone, particularly in the early stages, are suspected to be due the high protein-aminoacid and low water content of the Porphyra. Also, high NO3 content may be important to improve the bacterial flora in the animals, which in turn may favor more efficient digestion. Changes in the composition of Porphyra, however, can occur rapidly due to environmental conditions decreasing the nutritional value of the plant. Short term N pulse fertilization were performed on P. perforata in order to evaluate the feasibility to increase its nutritional value. Enrichment was performed under low light conditions (<5 ,E m -2 s -1) to inhibit growth and promote higher N enrichment per unit of biomass. Tissue N in the form of NO3, NH4 and total organic N were measured, after 3,6,12 and 24 hrs, in tissue exposed to 500 ,M of N. Results indicated a rapid N tissue enrichment particularly in the form of NO3. Nitrate accumulation occurs continuously, up to 24 hrs. Total organic N is maximum after 12 hrs and tends to decrease after that. Fertilization with NH4 promotes NO3 accumulation. These results suggest the feasibility to improve the nutritional value of P. perforata by short-term pulse fertilization. The capacity of this species to uptake NH4 under low light conditions (similar to those use in abalone culturing) makes it also ideal for integrated aquaculture. [source]
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