WorldWideScience

Sample records for dynamic root exudation

  1. Root exudate as major player on soil-water retention dynamics

    Science.gov (United States)

    Albalasmeh, A. A.; Sweet, J. R.; Gebrenegus, T. B.; Ghezzehei, T. A.

    2012-12-01

    Plant roots and soil microbes release 5-60% of the entirety of photosynthetically fixed carbon in to the soil as exudates to adapt to their surrounding. There is indirect evidence suggesting that these exudates play a major role in altering the of the soil water retention properties. In this study, we used a uniformly sized (40 μm) glass beads and various concentrations (0, 2, 10, 20 and 29 g/L) of polygalacutronic acid (PGA) to mimic sandy soil and the organic exudates from plant roots, respectively. The samples were subjected to periods of drying and subsequent equilibration. At each stage, the water potential was measured using WP4C Dewpoint PotentiaMeter. The effect of root exudates on soil water retention can be attributed t at least two factors. The most widely speculated effect is through enhanced of soil aggregation. This effect is primarily due to capillary adhesion in fine pores within aggregates and is consistent was visual observation of pronounced aggregation in many rhizosphere soils. The second factor is related to osmotic effect of the exudate solution. Our observations show that the capillary effect is mostly to higher water potential regime (> -1 bar suction). Whereas the osmotic effect dominates in plant-soil relations.

  2. Action of plant root exudates in bioremediations: a review

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    Peter Dundek

    2011-01-01

    Full Text Available This work presents a summary of literature dealing with the use of plant root exudates in bioremediations. Bioremediation using plants (phytoremediation or rhizoremediation and associate rhizosphere to decontaminate polluted soil is a method based on the catabolic potential of root-associated microorganisms, which are supported by the organic substrates released from roots. These substrates are called “root exudates”. Root exudates support metabolism of pollutants-decomposing microorganisms in the rhizosphere, and affect sorption / desorption of pollutants. Awareness of exudation rates is necessary for testing soil decontamination. Commonly, water-soluble root exudates of different plants are studied for their qualitative composition which should be related to total carbon of exuded water-soluble compounds. This paper presents the determined rate of plant root exudation and the amount of root exudates carbon used to form artificial rhizosphere.

  3. Nature and role of root exudates: Efficacy in bioremediation | Shukla ...

    African Journals Online (AJOL)

    Root exudate is one of the ways for plant communication to the neighboring plant and adjoining of microorganisms present in the rhizosphere of the root. The chemicals ingredients of the root exudates are specific to a particular plant species and also depend on the nearby biotic and abiotic environment. The chemical ...

  4. Modeling of Nonlinear Dynamics and Synchronized Oscillations of Microbial Populations, Carbon and Oxygen Concentrations, Induced by Root Exudation in the Rhizosphere

    Science.gov (United States)

    Molz, F. J.; Faybishenko, B.; Jenkins, E. W.

    2012-12-01

    Mass and energy fluxes within the soil-plant-atmosphere continuum are highly coupled and inherently nonlinear. The main focus of this presentation is to demonstrate the results of numerical modeling of a system of 4 coupled, nonlinear ordinary differential equations (ODEs), which are used to describe the long-term, rhizosphere processes of soil microbial dynamics, including the competition between nitrogen-fixing bacteria and those unable to fix nitrogen, along with substrate concentration (nutrient supply) and oxygen concentration. Modeling results demonstrate the synchronized patterns of temporal oscillations of competing microbial populations, which are affected by carbon and oxygen concentrations. The temporal dynamics and amplitude of the root exudation process serve as a driving force for microbial and geochemical phenomena, and lead to the development of the Gompetzian dynamics, synchronized oscillations, and phase-space attractors of microbial populations and carbon and oxygen concentrations. The nonlinear dynamic analysis of time series concentrations from the solution of the ODEs was used to identify several types of phase-space attractors, which appear to be dependent on the parameters of the exudation function and Monod kinetic parameters. This phase space analysis was conducted by means of assessing the global and local embedding dimensions, correlation time, capacity and correlation dimensions, and Lyapunov exponents of the calculated model variables defining the phase space. Such results can be used for planning experimental and theoretical studies of biogeochemical processes in the fields of plant nutrition, phyto- and bio-remediation, and other ecological areas.

  5. Root Exudate Effect on Germination and Mycelial Growth of ...

    African Journals Online (AJOL)

    The effect of some root exudates on the germination and mycelial growth of sclerotia of Sclerotium rolfsii Sacc. was studied. Root exudates of 5 – 10 days old seedlings from five plants viz: - tomato (Lycopersicum esculenta) maize (Zea mays), garden egg (Solanum melongena), pigeon pea (Cajanus cajan), and pepper ...

  6. Effects of Tomato Root Exudates on Meloidogyne incognita.

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    Guodong Yang

    Full Text Available Plant root exudates affect root-knot nematodes egg hatch. Chemicals in root exudates can attract nematodes to the roots or result in repellence, motility inhibition or even death. However, until recently little was known about the relationship between tomato root exudates chemicals and root-knot nematodes. In this study, root exudates were extracted from three tomato rootstocks with varying levels of nematode resistance: Baliya (highly resistant, HR, RS2 (moderately resistant, MR and L-402 (highly susceptible, T. The effects of the root exudates on Meloidogyne incognita (M. incognita egg hatch, survival and chemotaxis of second-stage juveniles (J2 were explored. The composition of the root exudates was analysed by gas chromatography/mass spectrometry (GC/MS prior to and following M. incognita inoculation. Four compounds in root exudates were selected for further analysis and their allopathic effect on M. incognita were investigated. Root exudates from each tomato rootstocks (HR, MR and T strains suppressed M. incognita egg hatch and increased J2 mortality, with the highest rate being observed in the exudates from the HR plants. Exudate from HR variety also repelled M. incognita J2 while that of the susceptible plant, T, was demonstrated to be attractive. The relative amount of esters and phenol compounds in root exudates from HR and MR tomato rootstocks increased notably after inoculation. Four compounds, 2,6-Di-tert-butyl-p-cresol, L-ascorbyl 2,6-dipalmitate, dibutyl phthalate and dimethyl phthalate increased significantly after inoculation. The egg hatch of M. incognita was suppressed by each of the compound. L-ascorbyl 2,6-dipalmitate showed the most notable effect in a concentration-dependent manner. All four compounds were associated with increased J2 mortality. The greatest effect was observed with dimethyl phthalate at 2 mmol·L-1. Dibutyl phthalate was the only compound observed to repel M. incognita J2 with no effect being detected in

  7. How Plant Root Exudates Shape the Nitrogen Cycle.

    Science.gov (United States)

    Coskun, Devrim; Britto, Dev T; Shi, Weiming; Kronzucker, Herbert J

    2017-08-01

    Although the global nitrogen (N) cycle is largely driven by soil microbes, plant root exudates can profoundly modify soil microbial communities and influence their N transformations. A detailed understanding is now beginning to emerge regarding the control that root exudates exert over two major soil N processes - nitrification and N 2 fixation. We discuss recent breakthroughs in this area, including the identification of root exudates as nitrification inhibitors and as signaling compounds facilitating N-acquisition symbioses. We indicate gaps in current knowledge, including questions of how root exudates affect newly discovered microbial players and N-cycle components. A better understanding of these processes is urgent given the widespread inefficiencies in agricultural N use and their links to N pollution and climate change. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Root Exudation in Common Ragweed (Ambrosia Artemisiifolia L.)

    Czech Academy of Sciences Publication Activity Database

    Figala, J.; Hohnová, Barbora; Moravcová, Dana; Lvončík, S.; Lojková, L.; Formánek, P.

    2016-01-01

    Roč. 5, č. 5 (2016), s. 1034-1037 ISSN 2278-1862 Institutional support: RVO:68081715 Keywords : ambrosia artemisiifolia * root exudates * amino acids * aliphatic organic acids * allelopathy Subject RIV: CB - Analytical Chemistry, Separation

  9. Methods of plant root exudates analysis: a review

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    Peter Dundek

    2011-01-01

    Full Text Available The aim of this review is to summarise current knowledge on methods being used to determine individual compounds and properties of water-soluble plant root exudates. These compounds include amino acids, organic acids and simple sugars, as well as polysaccharides, proteins and organic substances. Qualitative composition of water-soluble root exudates and exudation rate are commonly measured with the aim of consequent synthetic preparation of plant root exudates to be supplied to soil to create artificial rhizosphere for different experimental purposes. Root exudates collection usually requires consequent filtration or centrifugation to remove solids, root detritus and microbial cell debris, and consequent concentration using an evaporator, lyophilizator or ultrafiltration. Methods used for analysis of total groups of compounds (total proteins and total carbohydrates and total organic carbon are simple. On the other hand, HPLC or GS/MS are commonly used to analyse individual low molecular weight organic molecules (sugars, organic acids and amino acids with separation using different columns. Other properties such as pH, conductivity or activity of different enzymes as well as gel electrophoresis of proteins are sometimes assessed. All of these methods are discussed in this work.

  10. Low Light Availability Alters Root Exudation and Reduces Putative Beneficial Microorganisms in Seagrass Roots

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    Belinda C. Martin

    2018-01-01

    Full Text Available Seagrass roots host a diverse microbiome that is critical for plant growth and health. Composition of microbial communities can be regulated in part by root exudates, but the specifics of these interactions in seagrass rhizospheres are still largely unknown. As light availability controls primary productivity, reduced light may impact root exudation and consequently the composition of the root microbiome. Hence, we analyzed the influence of light availability on root exudation and community structure of the root microbiome of three co-occurring seagrass species, Halophila ovalis, Halodule uninervis and Cymodocea serrulata. Plants were grown under four light treatments in mesocosms for 2 weeks; control (100% surface irradiance (SI, medium (40% SI, low (20% SI and fluctuating light (10 days 20% and 4 days 100%. 16S rDNA amplicon sequencing revealed that microbial diversity, composition and predicted function were strongly influenced by the presence of seagrass roots, such that root microbiomes were unique to each seagrass species. Reduced light availability altered seagrass root exudation, as characterized using fluorescence spectroscopy, and altered the composition of seagrass root microbiomes with a reduction in abundance of potentially beneficial microorganisms. Overall, this study highlights the potential for above-ground light reduction to invoke a cascade of changes from alterations in root exudation to a reduction in putative beneficial microorganisms and, ultimately, confirms the importance of the seagrass root environment – a critical, but often overlooked space.

  11. A review of the influence of root-associating fungi and root exudates on the success of invasive plants

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    Cindy Bongard

    2012-08-01

    Full Text Available Plant-fungal interactions are essential for understanding the distribution and abundance of plants species. Recently, arbuscular mycorrhizal fungal (AMF partners of non-indigenous invasive plants have been hypothesized to be a critical factor influencing the invasion processes. AMF are known to improve nutrient and moisture uptake, as well as disrupt parasitic and pathogenic microbes in the host plant. Such benefits may enable invaders to establish significant and persistent populations in environments previously dominated by natives. Coupling these findings with studies on invader pathogen-disrupting root exudates is not well documented in the literature describing plant invasion strategies. The interaction effects of altered AMF associations and the impact of invader root exudates would be more relevant than understanding the AMF dynamics or the phytochemistry of successful invaders in isolation, particularly given that AMF and root exudates can have a similar role in pathogen control but function quite differently. One means to achieve this goal is to assess these strategies concurrently by characterizing both the general (mostly pathogens or commensals and AM-specific fungal colonization patterns found in field collected root samples of successful invaders, native plants growing within dense patches of invaders, and native plants growing separately from invaders. In this review I examine the emerging evidence of the ways in which AMF-plant interactions and the production of defensive root exudates provide pathways to invasive plant establishment and expansion, and conclude that interaction studies must be pursued to achieve a more comprehensive understanding of successful plant invasion.

  12. Root Exudation: The Ecological Driver of Hydrocarbon Rhizoremediation

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    Fanny Rohrbacher

    2016-03-01

    Full Text Available Rhizoremediation is a bioremediation technique whereby microbial degradation of organic contaminants occurs in the rhizosphere. It is considered to be an effective and affordable “green technology” for remediating soils contaminated with petroleum hydrocarbons. Root exudation of a wide variety of compounds (organic, amino and fatty acids, carbohydrates, vitamins, nucleotides, phenolic compounds, polysaccharides and proteins provide better nutrient uptake for the rhizosphere microbiome. It is thought to be one of the predominant drivers of microbial communities in the rhizosphere and is therefore a potential key factor behind enhanced hydrocarbon biodegradation. Many of the genes responsible for bacterial adaptation in contaminated soil and the plant rhizosphere are carried by conjugative plasmids and transferred among bacteria. Because root exudates can stimulate gene transfer, conjugation in the rhizosphere is higher than in bulk soil. A better understanding of these phenomena could thus inform the development of techniques to manipulate the rhizosphere microbiome in ways that improve hydrocarbon bioremediation.

  13. Pea-root exudates and their effect upon root-nodule bacteria

    NARCIS (Netherlands)

    Egeraat, van A.W.S.M.

    1972-01-01

    The main purpose of this investigation was to study the exudation (mechanism, sites) of various compounds by roots of pea seedlings in relation to the growth of Rhizobium leguminosarum.

    Chapter 1 gives a survey of the literature pertaining to plant-root

  14. Root exudation of phytosiderophores from soil-grown wheat

    Science.gov (United States)

    Oburger, Eva; Gruber, Barbara; Schindlegger, Yvonne; Schenkeveld, Walter D C; Hann, Stephan; Kraemer, Stephan M; Wenzel, Walter W; Puschenreiter, Markus

    2014-01-01

    For the first time, phytosiderophore (PS) release of wheat (Triticum aestivum cv Tamaro) grown on a calcareous soil was repeatedly and nondestructively sampled using rhizoboxes combined with a recently developed root exudate collecting tool. As in nutrient solution culture, we observed a distinct diurnal release rhythm; however, the measured PS efflux was c. 50 times lower than PS exudation from the same cultivar grown in zero iron (Fe)-hydroponic culture. Phytosiderophore rhizosphere soil solution concentrations and PS release of the Tamaro cultivar were soil-dependent, suggesting complex interactions of soil characteristics (salinity, trace metal availability) and the physiological status of the plant and the related regulation (amount and timing) of PS release. Our results demonstrate that carbon and energy investment into Fe acquisition under natural growth conditions is significantly smaller than previously derived from zero Fe-hydroponic studies. Based on experimental data, we calculated that during the investigated period (21–47 d after germination), PS release initially exceeded Fe plant uptake 10-fold, but significantly declined after c. 5 wk after germination. Phytosiderophore exudation observed under natural growth conditions is a prerequisite for a more accurate and realistic assessment of Fe mobilization processes in the rhizosphere using both experimental and modeling approaches. PMID:24890330

  15. Decreased levels of matrix metalloproteinase-2 in root-canal exudates during root canal treatment.

    Science.gov (United States)

    Pattamapun, Kassara; Handagoon, Sira; Sastraruji, Thanapat; Gutmann, James L; Pavasant, Prasit; Krisanaprakornkit, Suttichai

    2017-10-01

    To determine the matrix metalloproteinase-2 (MMP-2) levels in root-canal exudates from teeth undergoing root-canal treatment. The root-canal exudates from six teeth with normal pulp and periradicular tissues that required intentional root canal treatment for prosthodontic reasons and from twelve teeth with pulp necrosis and asymptomatic apical periodontitis (AAP) were sampled with paper points for bacterial culture and aspirated for the detection of proMMP-2 and active MMP-2 by gelatin zymography and the quantification of MMP-2 levels by ELISA. By gelatin zymography, both proMMP-2 and active MMP-2 were detected in the first collection of root-canal exudates from teeth with pulp necrosis and AAP, but not from teeth with normal pulp, and their levels gradually decreased and disappeared at the last collection. Consistently, ELISA demonstrated a significant decrease in MMP-2 levels in the root-canal exudates of teeth with pulp necrosis and AAP following root canal procedures (papical lesions, similar to the clinical application of MMP-8 as a biomarker. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Root exudates from grafted-root watermelon showed a certain contribution in inhibiting Fusarium oxysporum f. sp. niveum.

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    Ning Ling

    Full Text Available Grafting watermelon onto bottle gourd rootstock is commonly used method to generate resistance to Fusarium oxysporum f. sp. niveum (FON, but knowledge of the effect of the root exudates of grafted watermelon on this soil-borne pathogen in rhizosphere remains limited. To investigate the root exudate profiles of the own-root bottle gourd, grafted-root watermelon and own-root watermelon, recirculating hydroponic culture system was developed to continuously trap these root exudates. Both conidial germination and growth of FON were significantly decreased in the presence of root exudates from the grafted-root watermelon compared with the own-root watermelon. HPLC analysis revealed that the composition of the root exudates released by the grafted-root watermelon differed not only from the own-root watermelon but also from the bottle gourd rootstock plants. We identified salicylic acid in all 3 root exudates, chlorogenic acid and caffeic acid in root exudates from own-root bottle gourd and grafted-root watermelon but not own-root watermelon, and abundant cinnamic acid only in own-root watermelon root exudates. The chlorogenic and caffeic acid were candidates for potentiating the enhanced resistance of the grafted watermelon to FON, therefore we tested the effects of the two compounds on the conidial germination and growth of FON. Both phenolic acids inhibited FON conidial germination and growth in a dose-dependent manner, and FON was much more susceptible to chlorogenic acid than to caffeic acid. In conclusion, the key factor in attaining the resistance to Fusarium wilt is grafting on the non-host root stock, however, the root exudates profile also showed some contribution in inhibiting FON. These results will help to better clarify the disease resistance mechanisms of grafted-root watermelon based on plant-microbe communication and will guide the improvement of strategies against Fusarium-mediated wilt of watermelon plants.

  17. Transcriptomic profiling of Bacillus amyloliquefaciens FZB42 in response to maize root exudates

    LENUS (Irish Health Repository)

    Fan, Ben

    2012-06-21

    AbstractBackgroundPlant root exudates have been shown to play an important role in mediating interactions between plant growth-promoting rhizobacteria (PGPR) and their host plants. Most investigations were performed on Gram-negative rhizobacteria, while much less is known about Gram-positive rhizobacteria. To elucidate early responses of PGPR to root exudates, we investigated changes in the transcriptome of a Gram-positive PGPR to plant root exudates.ResultsBacillus amyloliquefaciens FZB42 is a well-studied Gram-positive PGPR. To obtain a comprehensive overview of FZB42 gene expression in response to maize root exudates, microarray experiments were performed. A total of 302 genes representing 8.2% of the FZB42 transcriptome showed significantly altered expression levels in the presence of root exudates. The majority of the genes (261) was up-regulated after incubation of FZB42 with root exudates, whereas only 41 genes were down-regulated. Several groups of the genes which were strongly induced by the root exudates are involved in metabolic pathways relating to nutrient utilization, bacterial chemotaxis and motility, and non-ribosomal synthesis of antimicrobial peptides and polyketides.ConclusionsHere we present a transcriptome analysis of the root-colonizing bacterium Bacillus amyloliquefaciens FZB42 in response to maize root exudates. The 302 genes identified as being differentially transcribed are proposed to be involved in interactions of Gram-positive bacteria with plants.

  18. Effect of Sugar Maple Root Exudate on Seedlings of Northern Conifer Species

    Science.gov (United States)

    Carl H. Tubbs

    1976-01-01

    It has been shows that a root exudate of sugar maple reduces the growth of yellow birch. A laboratory test indicated that the growth of northern conifers is also reduced in sugar maple root exudate. Allelopathy may play an important role in survival of species on sites where sugar maple is abundant.

  19. Influence of Root Exudates and Soil on Attachment of Pasteuria penetrans to Meloidogyne arenaria.

    Science.gov (United States)

    Liu, Chang; Timper, Patricia; Ji, Pingsheng; Mekete, Tesfamariam; Joseph, Soumi

    2017-09-01

    The bacterium Pasteuria penetrans is a parasite of root-knot nematodes ( Meloidogyne spp.). Endospores of P. penetrans attach to the cuticle of second-stage juveniles (J2) and subsequently sterilize infected females. When encumbered by large numbers of spores, juveniles are less mobile and their ability to infect roots is reduced. This study looked at different factors that influence spore attachment of P. penetrans to the root-knot nematode Meloidogyne arenaria . Pretreatment of J2 with root exudates of eggplant ( Solanum melongena cv. Black beauty) reduced spore attachment compared with pretreatment with phosphate-buffered saline (PBS), suggesting that the nematode surface coat was altered or the spore recognition domains on the nematode surface were blocked. Spore attachment was equally reduced following exposure to root exudates from both host and nonhost plants for M. arenaria , indicating a common signal that affects spore attachment. Although phytohormones have been shown to influence the lipophilicity of the nematode surface coat, auxins and kinetins did not affect spore attachment compared with PBS. Root exudates reduced spore attachment more in sterilized soil than in natural soil. Sterilization may have eliminated microbes that consume root exudates, or altered the chemical components of the soil solution or root exudates. Root exudates caused a greater decrease in spore attachment in loamy sand than in a sandy loam soil. The sandy loam had higher clay content than the loamy sand, which may have resulted in more adsorption of compounds in the root exudates that affect spore attachment. The components of the root exudates could have also been modified by soil type. The results of this study demonstrate that root exudates can decrease the attachment of P. penetrans endospores to root-knot nematodes, indicating that when these nematodes enter the root zone their susceptibility to spore attachment may decrease.

  20. Distribution of root exudates and mucilage in the rhizosphere: combining 14C imaging with neutron radiography

    Science.gov (United States)

    Holz, Maire; Carminati, Andrea; Kuzyakov, Yakov

    2015-04-01

    exudates. We found that mucilage and 14C concentrations were higher around the young root segments. Mucilage concentration was particularly high in the most apical 3-5 cm of the roots. Drought stress increased 14C exudation relative to C fixation and led to higher mucilage concentrations around roots. However, it remains unclear, whether the lower mucilage concentration around roots grown at higher soil moisture was caused by the faster diffusion of mucilage in wet soils. Therefore, a second experiment was focused on diffusion of mucilage in soil at varying water contents. The diffusion of mucilage in soil was not very sensitive to soil water content. We conclude that mucilage release was higher for plants exposed to drought stress. In summary, the combination of neutron radiography and 14C imaging can successfully be used to visualize and to quantify the distribution of mucilage and root exudates in the rhizosphere of plants grown in soil. References Kroener, E., Zarebanadkouki, M., Kaestner, A., & Carmintati, A. (2014). Nonequilibrium water dynamics in the rhizosphere: How mucilage affects water flow in soils. Water Resources Research, 37. Pausch, J., & Kuzyakov, Y. (2011). Photoassimilate allocation and dynamics of hotspots in roots visualized by 14C phosphor imaging. Journal of Plant Nutrition and Soil Science, 174(1), 12-19.

  1. The inflow of Cs-137 in soil with root litter and root exudates of Scots pine

    Science.gov (United States)

    Shcheglov, Alexey; Tsvetnova, Olga; Popova, Evgenia

    2017-04-01

    In the model experiment on evaluation of Cs-137 inflow in the soil with litter of roots and woody plants root exudates on the example of soil and water cultures of Scots pine (Pinus sylvestris L.) was shown, that through 45 days after the deposit Cs-137 solution on pine needles (specific activity of solution was 3.718*106 Bk) of the radionuclide in all components of model systems has increased significantly: needles, small branches and trunk by Cs-137 surface contamination during the experiment; roots as a result of the internal distribution of the radionuclide in the plant; soil and soil solution due to the of receipt Cs-137 in the composition of root exudates and root litter. Over 99% of the total reserve of Cs-137 accumulated in the components of the soil and water systems, accounted for bodies subjected to external pollution (needles and small branches) and soil solution, haven't been subjected to surface contamination. At the same contamination of soil and soil solution by Cs-137 in the model experiment more than a> 99.9% was due to root exudates

  2. Phytotoxicity of sorgoleone found in grain Sorghum root exudates.

    Science.gov (United States)

    Einhellig, F A; Souza, I F

    1992-01-01

    Root exudates ofSorghum bicolor consist primarily of a dihydroquinone that is quickly oxidized to ap-benzoquinone named sorgoleone. The aim of this investigation was to determine the potential activity of sorgoleone as an inhibitor of weed growth. Bioassays showed 125μM sorgoleone reduced radicle elongation ofEragrostis tef. In liquid culture, 50-μM sorgoleone treatments stunted the growth ofLemna minor. Over a 10-day treatment period, 10μM sorgoleone in the nutrient medium reduced the growth of all weed seedlings tested:Abutilon theophrasti, Datura stramonium, Amaranthus retroflexus, Setaria viridis, Digitaria sanguinalis, andEchinochloa crusgalli. These data show sorgoleone has biological activity at extremely low concentrations, suggesting a strong contribution toSorghum allelopathy.

  3. Dehydrocostus lactone is exuded from sunflower roots and stimulates germination of the root parasite Orobanche cumana.

    Science.gov (United States)

    Joel, Daniel M; Chaudhuri, Swapan K; Plakhine, Dina; Ziadna, Hammam; Steffens, John C

    2011-05-01

    The germination of the obligate root parasites of the Orobanchaceae depends on the perception of chemical stimuli from host roots. Several compounds, collectively termed strigolactones, stimulate the germination of the various Orobanche species, but do not significantly elicit germination of Orobanche cumana, a specific parasite of sunflower. Phosphate starvation markedly decreased the stimulatory activity of sunflower root exudates toward O. cumana, and fluridone - an inhibitor of the carotenoid biosynthesis pathway - did not inhibit the production of the germination stimulant in both shoots and roots of young sunflower plants, indicating that the stimulant is not a strigolactone. We identified the natural germination stimulant from sunflower root exudates by bioassay-driven purification. Its chemical structure was elucidated as the guaianolide sesquiterpene lactone dehydrocostus lactone (DCL). Low DCL concentrations effectively stimulate the germination of O. cumana seeds but not of Phelipanche aegyptiaca (syn. Orobanche aegyptiaca). DCL and other sesquiterpene lactones were found in various plant organs, but were previously not known to be exuded to the rhizosphere where they can interact with other organisms. Copyright © 2011 Elsevier Ltd. All rights reserved.

  4. Metabolite Profiling of Root Exudates of Common Bean under Phosphorus Deficiency

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    Keitaro Tawaraya

    2014-07-01

    Full Text Available Root exudates improve the nutrient acquisition of plants and affect rhizosphere microbial communities. The plant nutrient status affects the composition of root exudates. The purpose of this study was to examine common bean (Phaseolus vulgaris L. root exudates under phosphorus (P deficiency using a metabolite profiling technique. Common bean plants were grown in a culture solution at P concentrations of 0 (P0, 1 (P1 and 8 (P8 mg P L−1 for 1, 10 and 20 days after transplanting (DAT. Root exudates were collected, and their metabolites were determined by capillary electrophoresis time-of-flight mass spectrometry (CE-TOF MS. The shoot P concentration and dry weight of common bean plants grown at P0 were lower than those grown at P8. One hundred and fifty-nine, 203 and 212 metabolites were identified in the root exudates, and 16% (26/159, 13% (26/203 and 9% (20/212 of metabolites showed a P0/P8 ratio higher than 2.0 at 1, 10 and 20 DAT, respectively. The relative peak areas of several metabolites, including organic acids and amino acids, in root exudates were higher at P0 than at P8. These results suggest that more than 10% of primary and secondary metabolites are induced to exude from roots of common bean by P deficiency.

  5. Studies on photosynthate distribution and root exudates of cinesische by 14C tracer technique

    International Nuclear Information System (INIS)

    Chen Junwei; Ni Zhuru; Liu Zhihong; Fu Zhijian

    1994-01-01

    Cinesische (Cunninghamia sinesis R. Br.) plants grown in nutrient solution were exposed to 14 CO 2 for 24 hours to study the photosynthate distribution and root exudates. One day after feeding 14 CO 2 , the majority of 14 C assimilate was remained in leaves, only 27.38% of 14 C assimilate was translocated into new shoots, main branches, lateral branches and roots. 3 days after feeding 14 CO 2 , the distribution rate of 14 C photosynthate in leaves was still the highest, but the percentage decreased and it correspondingly increased in other plant parts. 22 days after feeding 14 CO 2 , the distribution rate in new shoots became the highest, roots ranked the second, main branches were the third, leaves and lateral branches were the lowest. The photosynthate in the root could rapidly convert into root exudates. The amount of root exudates reached a peak after 4 days of feeding 14 CO 2 , afterward the amount of 14 C root exudates decreased rapidly. The amount of sugar was the highest among all kinds of root exudates, the amount of organic acid was the second, the content of amino acid was much lower than that of the other two root exudates

  6. Fagopyrum esculentum Alters Its Root Exudation after Amaranthus retroflexus Recognition and Suppresses Weed Growth.

    Science.gov (United States)

    Gfeller, Aurélie; Glauser, Gaétan; Etter, Clément; Signarbieux, Constant; Wirth, Judith

    2018-01-01

    Weed control by crops through growth suppressive root exudates is a promising alternative to herbicides. Buckwheat ( Fagopyrum esculentum ) is known for its weed suppression and redroot pigweed ( Amaranthus retroflexus ) control is probably partly due to allelopathic root exudates. This work studies whether other weeds are also suppressed by buckwheat and if the presence of weeds is necessary to induce growth repression. Buckwheat and different weeds were co-cultivated in soil, separating roots by a mesh allowing to study effects due to diffusion. Buckwheat suppressed growth of pigweed, goosefoot and barnyard grass by 53, 42, and 77% respectively without physical root interactions, probably through allelopathic compounds. Root exudates were obtained from sand cultures of buckwheat (BK), pigweed (P), and a buckwheat/pigweed mixed culture (BK-P). BK-P root exudates inhibited pigweed root growth by 49%. Characterization of root exudates by UHPLC-HRMS and principal component analysis revealed that BK and BK-P had a different metabolic profile suggesting that buckwheat changes its root exudation in the presence of pigweed indicating heterospecific recognition. Among the 15 different markers, which were more abundant in BK-P, tryptophan was identified and four others were tentatively identified. Our findings might contribute to the selection of crops with weed suppressive effects.

  7. Roles of abiotic losses, microbes, plant roots, and root exudates on phytoremediation of PAHs in a barren soil.

    Science.gov (United States)

    Sun, Tian-Ran; Cang, Long; Wang, Quan-Ying; Zhou, Dong-Mei; Cheng, Jie-Min; Xu, Hui

    2010-04-15

    Phytoremediation is an emerging technology for the remediation of polycyclic aromatic hydrocarbons (PAHs). In this study, pot experiments were conducted to evaluate the efficacy of phytoremediation of phenanthrene and pyrene in a typical low organic matter soil (3.75 g kg(-1)), and the contribution proportions of abiotic losses, microbes, plant roots, and root exudates were ascertained during the PAHs dissipation. The results indicated that contribution of abiotic losses from this soil was high both for phenanthrene (83.4%) and pyrene (57.2%). The contributions of root-exudates-enhanced biodegradation of phenanthrene (15.5%) and pyrene (21.3%) were higher than those of indigenous microbial degradation. The role of root exudates on dissipation of phenanthrene and pyrene was evident in this experiment. By the way, with the increasing of ring numbers in PAHs structures, the root-exudates-enhanced degradation became more and more important. BIOLOG-ECO plate analysis indicated that microbial community structure of the soil receiving root exudates had changed. The removal efficiency and substrate utilization rate in the treatment with plant roots were lower than the treatment only with root exudates, which suggested that possible competition between roots and microbes for nutrients had occurred in a low organic matter soil. 2009. Published by Elsevier B.V.

  8. Potential of Root Exudates from Wetland Plants and Their Potential Role for Denitrification and Allelopathic Interactions

    DEFF Research Database (Denmark)

    Zhai, Xu

    Root exudates from wetland plants have both positive and negative interactions among microbe, plants and ecosystems. Wetland species releasing organic carbon into the rhizosphere for providing energy to denitrifying bacteria fuel denitrification for removal nitrogen in subsurface flow constructed...... wetlands. Furthermore, environmental factors such as temperature and light-regime affect the photosynthetic carbon fixation, which continuously influence the compositions and quantity of root exudates released into rhizosphere. Conversely, root exudates from invasive species might contain some phytotoxic...... chemicals to suppress the growth of native species. Phragmites australis is recognized as the most invasive species in wetland ecosystems in North America, and allelopathy has been reported to be involved in the invasion success of the introduced exotic P. australis. The composition of the root exudates may...

  9. Evolutionary Divergences in Root Exudate Composition among Ecologically-Contrasting Helianthus Species.

    Science.gov (United States)

    Bowsher, Alan W; Ali, Rifhat; Harding, Scott A; Tsai, Chung-Jui; Donovan, Lisa A

    2016-01-01

    Plant roots exude numerous metabolites into the soil that influence nutrient availability. Although root exudate composition is hypothesized to be under selection in low fertility soils, few studies have tested this hypothesis in a phylogenetic framework. In this study, we examined root exudates of three pairs of Helianthus species chosen as phylogenetically-independent contrasts with respect to native soil nutrient availability. Under controlled environmental conditions, seedlings were grown to the three-leaf-pair stage, then transferred to either high or low nutrient treatments. After five days of nutrient treatments, we used gas chromatography-mass spectrometry for analysis of root exudates, and detected 37 metabolites across species. When compared in the high nutrient treatment, species native to low nutrient soils exhibited overall higher exudation than their sister species native to high nutrient soils in all three species pairs, providing support for repeated evolutionary shifts in response to native soil fertility. Species native to low nutrient soils and those native to high nutrient soils responded similarly to low nutrient treatments with increased exudation of organic acids (fumaric, citric, malic acids) and glucose, potentially as a mechanism to enhance nutrition acquisition. However, species native to low nutrient soils also responded to low nutrient treatments with a larger decrease in exudation of amino acids than species native to high nutrient soils in all three species pairs. This indicates that species native to low nutrient soils have evolved a unique sensitivity to changes in nutrient availability for some, but not all, root exudates. Overall, these repeated evolutionary divergences between species native to low nutrient soils and those native to high nutrient soils provide evidence for the adaptive value of root exudation, and its plasticity, in contrasting soil environments.

  10. Bacteria from wheat and cucurbit plant roots metabolize PAHs and aromatic root exudates: Implications for rhizodegradation.

    Science.gov (United States)

    Ely, Cairn S; Smets, Barth F

    2017-10-03

    The chemical interaction between plants and bacteria in the root zone can lead to soil decontamination. Bacteria that degrade polycyclic aromatic hydrocarbons (PAHs) have been isolated from the rhizospheres of plant species with varied biological traits; however, it is not known what phytochemicals promote contaminant degradation. One monocot and two dicotyledon plants were grown in PAH-contaminated soil from a manufactured gas plant (MGP) site. A phytotoxicity assay confirmed greater soil decontamination in rhizospheres when compared to bulk soil controls. Bacteria were isolated from plant roots (rhizobacteria) and selected for growth on anthracene and chrysene on PAH-amended plates. Rhizosphere isolates metabolized 3- and 4-ring PAHs and PAH catabolic intermediates in liquid incubations. Aromatic root exudate compounds, namely flavonoids and simple phenols, were also substrates for isolated rhizobacteria. In particular, the phenolic compounds-morin, caffeic acid, and protocatechuic acid-appear to be linked to bacterial degradation of 3- and 4-ring PAHs in the rhizosphere.

  11. Stress differentially impacts reserve pools and root exudation: implications for ecosystem functioning and carbon balance

    Science.gov (United States)

    Landhäusser, Simon; Karst, Justine; Wiley, Erin; Gaster, Jacob

    2016-04-01

    Environmental stress can influence carbon assimilation and the accumulation and distribution of carbon between growth, reserves, and exudation; however, it is unclear how these processes vary by different stress types. Partitioning of carbon to growth and reserves in plants might also vary between different organs. Roots reserves are of particular interest as they link the plant with the soil carbon cycle through exudation. Simple models of diffusion across concentration gradients predict the more C reserves in roots, the more C should be exuded from roots. However, the mechanisms underlying the accumulation and loss of C from roots may differ depending on the stress experienced by the plants. In a controlled study we tested whether different types of stresses (shade, cold soil, and drought) have differential effects on the distribution, abundance, and form (sugar vs. starch) of carbohydrates in seedlings, and whether these changes alone could explain differences in root exudation between stress types. Non-structural carbohydrate (NSC) concentration and pool sizes varied by stress type and between organs. Mass-specific C exudation increased with fine root sugar concentration; however, stress type affected exudation independently of reserve concentration. Seedlings exposed to cold soils exuded the most C on a per root mass basis followed by shade and drought. Through 13C labeling, we also found that depending on the stress type, aspen seedlings may be less able to control the loss of C to the soil compared with unstressed seedlings, resulting in more C leaked to the rhizosphere. The loss of C beyond that predicted by simple concentration gradients might have important implications for ecosystem functioning and carbon balance. If stressed plants lose proportionally more carbon to the soil, existing interactions between plants and soils may decouple under stress, and may include unexpected C fluxes between trees, soils and the atmosphere with a changing climate.

  12. Root exudation and root development of lettuce (Lactuca sativa L. cv. Tizian) as affected by different soils.

    Science.gov (United States)

    Neumann, G; Bott, S; Ohler, M A; Mock, H-P; Lippmann, R; Grosch, R; Smalla, K

    2014-01-01

    Development and activity of plant roots exhibit high adaptive variability. Although it is well-documented, that physicochemical soil properties can strongly influence root morphology and root exudation, particularly under field conditions, a comparative assessment is complicated by the impact of additional factors, such as climate and cropping history. To overcome these limitations, in this study, field soils originating from an unique experimental plot system with three different soil types, which were stored at the same field site for 10 years and exposed to the same agricultural management practice, were used for an investigation on effects of soil type on root development and root exudation. Lettuce (Lactuca sativa L. cv. Tizian) was grown as a model plant under controlled environmental conditions in a minirhizotrone system equipped with root observation windows (rhizoboxes). Root exudates were collected by placing sorption filters onto the root surface followed by subsequent extraction and GC-MS profiling of the trapped compounds. Surprisingly, even in absence of external stress factors with known impact on root exudation, such as pH extremes, water and nutrient limitations/toxicities or soil structure effects (use of sieved soils), root growth characteristics (root length, fine root development) as well as profiles of root exudates were strongly influenced by the soil type used for plant cultivation. The results coincided well with differences in rhizosphere bacterial communities, detected in field-grown lettuce plants cultivated on the same soils (Schreiter et al., this issue). The findings suggest that the observed differences may be the result of plant interactions with the soil-specific microbiomes.

  13. Root exudation and root development of lettuce (Lactuca sativa L.cv. Tizian as affected by different soils

    Directory of Open Access Journals (Sweden)

    Günter eNeumann

    2014-01-01

    Full Text Available Development and activity of plant roots exhibits high adaptive variability. Although it is well-documented, that physicochemical soil properties can strongly influence root morphology and root exudation, particularly under field conditions, a comparative assessment is complicated by the impact of additional factors, such as climate and cropping history. To overcome these limitations, in this study, field soils originating from an unique experimental plot system with three different soil types, which were stored at the same field site for ten years and exposed to the same agricultural management practice, were used for an investigation on effects of soil type on root development and root exudation. Lettuce (Lactuca sativa L. cv. Tizian was used as a model plant, grown under controlled environmental conditions in a minirhizotrone system equipped with root observation windows (rhizoboxes. Root exudates were collected by placing sorption filters onto the root surface followed by subsequent extraction and GC-MS profiling of the trapped compounds. Surprisingly, even in absence of external stress factors with known impact on root exudation, such as pH extremes, water and nutrient limitations/toxicities or soil structure effects (use of sieved soils, root growth characteristics (root length, fine root development as well as profiles of root exudates were strongly influenced by the soil type used for plant cultivation. The results coincided well with differences in rhizosphere bacterial communities, detected in field-grown lettuce plants cultivated on the same soils (Schreiter et al., this issue. The findings suggest that the observed differences may be the result of plant interactions with the soil-specific microbiomes.

  14. Root exudation and root development of lettuce (Lactuca sativa L. cv. Tizian) as affected by different soils

    Science.gov (United States)

    Neumann, G.; Bott, S.; Ohler, M. A.; Mock, H.-P.; Lippmann, R.; Grosch, R.; Smalla, K.

    2014-01-01

    Development and activity of plant roots exhibit high adaptive variability. Although it is well-documented, that physicochemical soil properties can strongly influence root morphology and root exudation, particularly under field conditions, a comparative assessment is complicated by the impact of additional factors, such as climate and cropping history. To overcome these limitations, in this study, field soils originating from an unique experimental plot system with three different soil types, which were stored at the same field site for 10 years and exposed to the same agricultural management practice, were used for an investigation on effects of soil type on root development and root exudation. Lettuce (Lactuca sativa L. cv. Tizian) was grown as a model plant under controlled environmental conditions in a minirhizotrone system equipped with root observation windows (rhizoboxes). Root exudates were collected by placing sorption filters onto the root surface followed by subsequent extraction and GC-MS profiling of the trapped compounds. Surprisingly, even in absence of external stress factors with known impact on root exudation, such as pH extremes, water and nutrient limitations/toxicities or soil structure effects (use of sieved soils), root growth characteristics (root length, fine root development) as well as profiles of root exudates were strongly influenced by the soil type used for plant cultivation. The results coincided well with differences in rhizosphere bacterial communities, detected in field-grown lettuce plants cultivated on the same soils (Schreiter et al., this issue). The findings suggest that the observed differences may be the result of plant interactions with the soil-specific microbiomes. PMID:24478764

  15. Preferential flow in the vadose zone and interface dynamics: Impact of microbial exudates

    Science.gov (United States)

    Li, Biting; Pales, Ashley R.; Clifford, Heather M.; Kupis, Shyla; Hennessy, Sarah; Liang, Wei-Zhen; Moysey, Stephen; Powell, Brian; Finneran, Kevin T.; Darnault, Christophe J. G.

    2018-03-01

    In the hydrological cycle, the infiltration process is a critical component in the distribution of water into the soil and in the groundwater system. The nonlinear dynamics of the soil infiltration process yield preferential flow which affects the water distribution in soil. Preferential flow is influenced by the interactions between water, soil, plants, and microorganisms. Although the relationship among the plant roots, their rhizodeposits and water transport in soil has been the subject of extensive study, the effect of microbial exudates has been studied in only a few cases. Here the authors investigated the influence of two artificial microbial exudates-catechol and riboflavin-on the infiltration process, particularly unstable fingered flow, one form of preferential flow. Flow experiments investigating the effects of types and concentrations of microbial exudates on unstable fingered flow were conducted in a two-dimensional tank that was filled with ASTM

  16. Influence of root exudates on attachment of Pasteuria penetrans to Meloidogyne arenaria

    Science.gov (United States)

    We hypothesized that root exudates would influence the spore attachment of Pasteuria penetrans to root-knot nematodes (Meloidogyne arenaria). An experiment was carried out using a factorial arrangement of two single spore (SS) lines cultured from P. penetrans and three single egg mass(SEM)lines cult...

  17. [Effects of wheat root exudates on cucumber growth and soil fungal community structure].

    Science.gov (United States)

    Wu, Feng-Zhi; Li, Min; Cao, Peng; Ma, Ya-Fei; Wang, Li-Li

    2014-10-01

    With wheat as the donor plant and cucumber as the receptor plant, this study investigated the effects of root exudates from wheat cultivars with different allelopathic potentials (positive or negative) and companion cropping with wheat on soil fungal community structure by PCR-DGGE method and cucumber growth. Results showed that the wheat root exudates with positive allelopathic potential increased height and stem diameter of cucumber seedlings significantly, compared to the control seedlings (W) after 6 days and 12 days treatment, respectively. Also, wheat root exudates with both positive and negative allelopathic potential increased the seedling height of cucumber significantly after 18 days treatment. The wheat root exudates with different allelopathic potentials decreased the band number, Shannon and evenness indices of soil fungal community significantly in cucumber seedling rhizosphere, and those in the soil with the control seedlings (W) were also significantly higher than that in the control soil without seedlings (Wn) after 6 days treatment. The band number, Shannon and evenness indices in all the treatments were significantly higher than those in the control soil without seedlings (Wn) after 18 days treatment. Companion cropping with negative allelopathic potential wheat decreased the Shannon and evenness indices of soil fungi community significantly in the cucumber seedling rhizosphere, suggesting the wheat root exudates and companion cropping with wheat changed soil fungal community structure in the cucumber seedling rhizosphere. The results of DGGE map and the principal component analysis showed that companion cropping with wheat cultivars with different allelopathic potentials changed soil fungal community structure in cucumber seedling rhizosphere.

  18. Effect of microcystins on root growth, oxidative response, and exudation of rice (Oryza sativa).

    Science.gov (United States)

    Cao, Qing; Rediske, Richard R; Yao, Lei; Xie, Liqiang

    2018-03-01

    A 30 days indoor hydroponic experiment was carried out to evaluate the effect of microcystins (MCs) on rice root morphology and exudation, as well as bioaccumulation of MCs in rice. MCs were bioaccumulated in rice with the greatest concentrations being observed in the leaves (113.68μgg -1 Fresh weight (FW)) when exposed to 500μgL -1 MCs. Root activity at 500μgL -1 decreased 37%, compared to the control. MCs also induced disruption of the antioxidant system and lipid peroxidation in rice roots. Root growth was significantly inhibited by MCs. Root weight, length; surface area and volume were significantly decreased, as well as crown root number and lateral root number. After 30 days exposure to MCs, an increase was found in tartaric acid and malic acid while the other organic acids were not affected. Glycine, tyrosine, and glutamate were the only amino acids stimulated at MCs concentrations of 500μgL -1 . Similarly, dissolved organic carbon (DOC) and carbohydrate at 50 and 500μgL -1 treatments were significantly increased. The increase of DOC and carbohydrate in root exudates was due to rice root membrane permeability changes induced by MCs. Overall, this study indicated that MCs significantly inhibited rice root growth and affected root exudation. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. Trigoxazonane, a monosubstituted trioxazonane from Trigonella foenum-graecum root exudate, inhibits Orobanche crenata seed germination.

    Science.gov (United States)

    Evidente, Antonio; Fernández-Aparicio, Mónica; Andolfi, Anna; Rubiales, Diego; Motta, Andrea

    2007-10-01

    Orobanche crenata is a major threat to grain legume production. Fenugreek (Trigonella foenum-graecum) is an annual legume that has been shown to effectively reduce O. crenata infection when intercropped with grain legumes. In this paper, we point that this can be attributed to allelopathy, through inhibition of the germination of O. crenata by fenugreek root exudates. The main inhibitory metabolite was isolated and characterized. Allelopathy was demonstrated in different bioassays, by inhibition of O. crenata seeds germination both by growing fenugreek and pea plants together (intercropped), and by application of fenugreek root exudates. Fenugreek root exudates were extracted with organic solvent and fractionated giving several fractions, two of which showed moderate (27%) and strong (54%) inhibition of O. crenata seed germination, respectively. The most active metabolite is a new monosubstituted trioxazonane, characterized by spectroscopic methods as the 2-butyl-[1,4,7,2]trioxazonane and named trigoxazonane.

  20. Root exudate-induced alterations in Bacillus cereus cell wall contribute to root colonization and plant growth promotion.

    Directory of Open Access Journals (Sweden)

    Swarnalee Dutta

    Full Text Available The outcome of an interaction between plant growth promoting rhizobacteria and plants may depend on the chemical composition of root exudates (REs. We report the colonization of tobacco, and not groundnut, roots by a non-rhizospheric Bacillus cereus (MTCC 430. There was a differential alteration in the cell wall components of B. cereus in response to the REs from tobacco and groundnut. Attenuated total reflectance infrared spectroscopy revealed a split in amide I region of B. cereus cells exposed to tobacco-root exudates (TRE, compared to those exposed to groundnut-root exudates (GRE. In addition, changes in exopolysaccharides and lipid-packing were observed in B. cereus grown in TRE-amended minimal media that were not detectable in GRE-amended media. Cell-wall proteome analyses revealed upregulation of oxidative stress-related alkyl hydroperoxide reductase, and DNA-protecting protein chain (Dlp-2, in response to GRE and TRE, respectively. Metabolism-related enzymes like 2-amino-3-ketobutyrate coenzyme A ligase and 2-methylcitrate dehydratase and a 60 kDa chaperonin were up-regulated in response to TRE and GRE. In response to B. cereus, the plant roots altered their exudate-chemodiversity with respect to carbohydrates, organic acids, alkanes, and polyols. TRE-induced changes in surface components of B. cereus may contribute to successful root colonization and subsequent plant growth promotion.

  1. Root exudation and root development of lettuce (Lactuca sativa L. cv. Tizian) as affected by different soils

    OpenAIRE

    Neumann, G.; Bott, S.; Ohler, M. A.; Mock, H.-P.; Lippmann, R.; Grosch, R.; Smalla, K.

    2014-01-01

    Development and activity of plant roots exhibits high adaptive variability. Although it is well-documented, that physicochemical soil properties can strongly influence root morphology and root exudation, particularly under field conditions, a comparative assessment is complicated by the impact of additional factors, such as climate and cropping history. To overcome these limitations, in this study, field soils originating from an unique experimental plot system with three different soil types...

  2. Effect of soil water content on spatial distribution of root exudates and mucilage in the rhizosphere

    Science.gov (United States)

    Holz, Maire; Zarebanadkouki, Mohsen; Kuzyakov, Yakov; Carminati, Andrea

    2016-04-01

    Water and nutrients are expected to become the major factors limiting food production. Plant roots employ various mechanisms to increase the access to these limited soil resources. Low molecular root exudates released into the rhizosphere increase nutrient availability, while mucilage improves water availability under low moisture conditions. However, studies on the spatial distribution and quantification of exudates in soil are scarce. Our aim was therefore to quantify and visualize root exudates and mucilage distribution around growing roots using neutron radiography and 14C imaging at different levels of water stress. Maize plants were grown in rhizotrons filled with a silty soil and were exposed to varying soil conditions, from optimal to dry. Mucilage distribution around the roots was estimated from the profiles of water content in the rhizosphere - note that mucilage increases the soil water content. The profiles of water content around different root types and root ages were measured with neutron radiography. Rhizosphere extension was approx. 0.7 mm and did not differ between wet and dry treatments. However, water content (i.e. mucilage concentration) in the rhizosphere of plants grown in dry soils was higher than for plants grown under optimal conditions. This effect was particularly pronounced near the tips of lateral roots. The higher water contents near the root are explained as the water retained by mucilage. 14C imaging of root after 14CO2 labeling of shoots (Pausch and Kuzyakov 2011) was used to estimate the distribution of all rhizodeposits. Two days after labelling, 14C distribution was measured using phosphor-imaging. To quantify 14C in the rhizosphere a calibration was carried out by adding given amounts of 14C-glucose to soil. Plants grown in wet soil transported a higher percentage of 14C to the roots (14Croot/14Cshoot), compared to plants grown under dry conditions (46 vs. 36 %). However, the percentage of 14C allocated from roots to

  3. Recognition of root exudates by seeds of broomrape (Orobanche and Phelipanche) species

    Science.gov (United States)

    Fernández-Aparicio, M.; Flores, F.; Rubiales, D.

    2009-01-01

    Background and Aims The long co-existence of broomrapes and their hosts within the same environment has culminated in a strong adaptation and effective parasitism. As a first step of specialization in the parasitic process, seed receptors of parasitic plant species vary in their ability to recognize compounds released by their hosts. This work aims to investigate potential patterns for the reception requirements needed to activate germination within Orobanche and Phelipanche species. Methods Induction of the germination of seeds of nine Orobanche and Pheliphanche species by root exudates of 41 plant species was studied and subjected to biplot multivariate analysis. Key Results A high level of specialization in root exudate recognition was found in Orobanche densiflora, O. gracilis and O. hederae, which germinated almost exclusively in contact with root exudates from the plants they infect in nature. At the opposite extreme, Phelipanche aegyptiaca, P. ramosa and O. minor were highly generalist, germinating when in contact with the root exudates of most plant species. Orobanche crenata, O. cumana and O. foetida showed intermediate behaviour. Conclusions A universal germination stimulant for all broomrape species has not being identified to date. The synthetic stimulant GR24 is active against most of the weedy broomrape species, but fails with the non-weedy species tested in this study and with the very recent weedy species O. foetida. In addition, germination behaviour of broomrape species depends on the crop plant tested. Weedy broomrapes with a broad host spectrum respond better to the different exudates released by a wide range of crops and wild species than do non-weedy broomrapes, which have a narrow host spectrum and are more restricted to their host range. Root exudates of many plant species were active in stimulating germination of seeds of Orobanche and Phelipanche species for which they are not described as hosts, representing interesting examples of

  4. Quantification and enzyme targets of fatty acid amides from duckweed root exudates involved in the stimulation of denitrification.

    Science.gov (United States)

    Sun, Li; Lu, Yufang; Kronzucker, Herbert J; Shi, Weiming

    2016-07-01

    Fatty acid amides from plant root exudates, such as oleamide and erucamide, have the ability to participate in strong plant-microbe interactions, stimulating nitrogen metabolism in rhizospheric bacteria. However, mechanisms of secretion of such fatty acid amides, and the nature of their stimulatory activities on microbial metabolism, have not been examined. In the present study, collection, pre-treatment, and determination methods of oleamide and erucamide in duckweed root exudates are compared. The detection limits of oleamide and erucamide by gas chromatography (GC) (10.3ngmL(-1) and 16.1ngmL(-1), respectively) are shown to be much lower than those by liquid chromatography (LC) (1.7 and 5.0μgmL(-1), respectively). Quantitative GC analysis yielded five times larger amounts of oleamide and erucamide in root exudates of Spirodela polyrrhiza when using a continuous collection method (50.20±4.32 and 76.79±13.92μgkg(-1) FW day(-1)), compared to static collection (10.88±0.66 and 15.27±0.58μgkg(-1) FW day(-1)). Furthermore, fatty acid amide secretion was significantly enhanced under elevated nitrogen conditions (>300mgL(-1)), and was negatively correlated with the relative growth rate of duckweed. Mechanistic assays were conducted to show that erucamide stimulates nitrogen removal by enhancing denitrification, targeting two key denitrifying enzymes, nitrate and nitrite reductases, in bacteria. Our findings significantly contribute to our understanding of the regulation of nitrogen dynamics by plant root exudates in natural ecosystems. Copyright © 2016 Elsevier GmbH. All rights reserved.

  5. Molecular responses in root-associative rhizospheric bacteria to variations in plant exudates

    Science.gov (United States)

    Abdoun, Hamid; McMillan, Mary; Pereg, Lily

    2015-04-01

    Plant exudates are a major factor in the interface of plant-soil-microbe interactions and it is well documented that the microbial community structure in the rhizosphere is largely influenced by the particular exudates excreted by various plants. Azospirillum brasilense is a plant growth promoting rhizobacterium that is known to interact with a large number of plants, including important food crops. The regulatory gene flcA has an important role in this interaction as it controls morphological differentiation of the bacterium that is essential for attachment to root surfaces. Being a response regulatory gene, flcA mediates the response of the bacterial cell to signals from the surrounding rhizosphere. This makes this regulatory gene a good candidate for analysis of the response of bacteria to rhizospheric alterations, in this case, variations in root exudates. We will report on our studies on the response of Azospirillum, an ecologically, scientifically and agriculturally important bacterial genus, to variations in the rhizosphere.

  6. Compost and biochar alter mycorrhization, tomato root exudation and development of Fusarium oxysporum f. sp. lycopersici

    Directory of Open Access Journals (Sweden)

    Adnan eAkhter

    2015-07-01

    Full Text Available Soil amendments like compost and biochar are known to affect soil properties, plant growth as well as soil borne plant pathogens. Complex interactions based on microbial activity and abiotic characteristics are supposed to be responsible for suppressive properties of certain substrates, however, the specific mechanisms of action are still widely unknown. In the present study, the main focus was on the development of the soil borne pathogen, Fusarium oxysporum f.sp. lycopersici (Fol in tomato (Solanum lycopersicum L. and changes in root exudates of tomato plants grown in different soil substrate compositions, such as compost (Comp alone at application rate of 20 % (v/v, and in combination with wood biochar (WB; made from beech wood chips or green waste biochar (GWB, made from garden waste residues at application rate of 3 % (v/v, and/or with additional arbuscular mycorrhizal fungi (AMF. The association of GWB and AMF had a positive effect on tomato plants growth unlike to the plants grown in WB containing soil substrate. The AMF root colonization was not enhanced by the addition of WB or GWB in the soil substrate, though bio-protective effect of mycorrhization was evident in both biochar amended treatments against Fol. Compost and biochars altered root exudates differently, which is evident from variable response of in vitro growth and development of Fol. The microconidia germination was highest under in root exudates from plants grown in the soil containing compost and GWB, whereas root exudates of plants from substrate containing WB suppressed the mycelial growth and development of Fol. In conclusion, the plant growth response and disease suppression in biochar containing substrates with additional AMF was affected by the feedstock type. Moreover, application of compost and biochars in the soil influence the quality and composition of root exudates with respect to their effects on soil-dwelling fungi.

  7. Metabolomes of Potato Root Exudates: Compounds That Stimulate Resting Spore Germination of the Soil-Borne Pathogen Spongospora subterranea.

    Science.gov (United States)

    Balendres, Mark A; Nichols, David S; Tegg, Robert S; Wilson, Calum R

    2016-10-12

    Root exudation has importance in soil chemical ecology influencing rhizosphere microbiota. Prior studies reported root exudates from host and nonhost plants stimulated resting spore germination of Spongospora subterranea, the powdery scab pathogen of potato, but the identities of stimulatory compounds were unknown. This study showed that potato root exudates stimulated S. subterranea resting spore germination, releasing more zoospores at an earlier time than the control. We detected 24 low molecular weight organic compounds within potato root exudates and identified specific amino acids, sugars, organic acids, and other compounds that were stimulatory to S. subterranea resting spore germination. Given that several stimulatory compounds are commonly found in exudates of diverse plant species, we support observations of nonhost-specific stimulation. We provide knowledge of S. subterranea resting spore biology and chemical ecology that may be useful in formulating new disease management strategies.

  8. New sesquiterpene lactones from sunflower root exudate as germination stimulants for Orobanche cumana.

    Science.gov (United States)

    Raupp, Frank M; Spring, Otmar

    2013-11-06

    Orobanche cumana is a serious threat for cultivation of sunflower in Europe and Asia. Germination of the parasite is induced by metabolites released from the host root system. The first germination stimulant from sunflower root exudate was recently identified as dehydrocostus lactone, a sesquiterpene lactone. Bioassay-guided fractionation of root exudates now showed the release of additional sesquiterpene lactones. Besides dehydrocostus lactone, costunolide, tomentosin, and 8-epixanthatin were purified and identified spectroscopically. All four compounds induced germination of O. cumana at nano- to micromolar concentrations. Costunolide and dehydrocostus lactone concentrations above 1 μM reduced the activity, and application of 100 μM inhibited germination irreversibly. Seeds of Phelipanche ramosa could not be induced with costunolide. O. cumana seeds also germinated with GR24, a synthetic strigolactone. No bioactive fraction of sunflower contained compounds of this type. This supports previous findings that sesquiterpene lactones instead of strigolactones trigger the sunflower/O. cumana interaction.

  9. Exploring the transfer of recent plant photosynthates to soil microbes: mycorrhizal pathway vs direct root exudation

    Science.gov (United States)

    Kaiser, Christina; Kilburn, Matt R; Clode, Peta L; Fuchslueger, Lucia; Koranda, Marianne; Cliff, John B; Solaiman, Zakaria M; Murphy, Daniel V

    2015-01-01

    Plants rapidly release photoassimilated carbon (C) to the soil via direct root exudation and associated mycorrhizal fungi, with both pathways promoting plant nutrient availability. This study aimed to explore these pathways from the root's vascular bundle to soil microbial communities. Using nanoscale secondary ion mass spectrometry (NanoSIMS) imaging and 13C-phospho- and neutral lipid fatty acids, we traced in-situ flows of recently photoassimilated C of 13CO2-exposed wheat (Triticum aestivum) through arbuscular mycorrhiza (AM) into root- and hyphae-associated soil microbial communities. Intraradical hyphae of AM fungi were significantly 13C-enriched compared to other root-cortex areas after 8 h of labelling. Immature fine root areas close to the root tip, where AM features were absent, showed signs of passive C loss and co-location of photoassimilates with nitrogen taken up from the soil solution. A significant and exclusively fresh proportion of 13C-photosynthates was delivered through the AM pathway and was utilised by different microbial groups compared to C directly released by roots. Our results indicate that a major release of recent photosynthates into soil leave plant roots via AM intraradical hyphae already upstream of passive root exudations. AM fungi may act as a rapid hub for translocating fresh plant C to soil microbes. PMID:25382456

  10. Disentangling the rhizosphere effect on nitrate reducers and denitrifiers: insight into the role of root exudates.

    Science.gov (United States)

    Henry, S; Texier, S; Hallet, S; Bru, D; Dambreville, C; Chèneby, D; Bizouard, F; Germon, J C; Philippot, L

    2008-11-01

    To determine to which extent root-derived carbon contributes to the effects of plants on nitrate reducers and denitrifiers, four solutions containing different proportions of sugar, organic acids and amino acids mimicking maize root exudates were added daily to soil microcosms at a concentration of 150 microg C g(-1) of soil. Water-amended soils were used as controls. After 1 month, the size and structure of the nitrate reducer and denitrifier communities were analysed using the narG and napA, and the nirK, nirS and nosZ genes as molecular markers respectively. Addition of artificial root exudates (ARE) did not strongly affect the structure or the density of nitrate reducer and denitrifier communities whereas potential nitrate reductase and denitrification activities were stimulated by the addition of root exudates. An effect of ARE composition was also observed on N(2)O production with an N(2)O:(N(2)O + N(2)) ratio of 0.3 in microcosms amended with ARE containing 80% of sugar and of 1 in microcosms amended with ARE containing 40% of sugar. Our study indicated that ARE stimulated nitrate reduction or denitrification activity with increases in the range of those observed with the whole plant. Furthermore, we demonstrated that the composition of the ARE affected the nature of the end-product of denitrification and could thus have a putative impact on greenhouse gas emissions.

  11. 14CO2 labeling. A reliable technique for rapid measurement of total root exudation capacity and vascular sap flow in crop plants

    International Nuclear Information System (INIS)

    Bhupinder Singh; Sumedha Ahuja; Renu Pandey; Singhal, R.K.

    2014-01-01

    Root release of organic compounds and rate of the vascular sap flow are important for understanding the nutrient and the source-sink dynamics in plants, however, their determination is procedurally cumbersome and time consuming. We report here a simple method involving 14 C labeling for rapid and reliable measurement of root exudates and vascular sap flow rate in a variable groundnut population developed through seed gamma irradiation using a cobalt source ( 60 Co). An experimental hypothesis that a higher 14 C level in the vascular sap would indicate a higher root release of carbon by the roots into the rhizosphere was verified. (author)

  12. Influence of cadmium stress on root exudates of high cadmium accumulating rice line (Oryza sativa L.).

    Science.gov (United States)

    Fu, Huijie; Yu, Haiying; Li, Tingxuan; Zhang, Xizhou

    2018-04-15

    A hydroponic experiment with two different cadmium (Cd) accumulating rice lines of Lu527-8 (the high Cd accumulating rice line) and Lu527-4 (the normal rice line) was carried out to explore the links among Cd stress, root exudates and Cd accumulation. The results showed that (1) Cd stress increased quantities of organic acids, but had no effect on composition in root exudates of the two rice lines. In Cd treatments, the contents of every detected organic acid in root exudates of Lu527-8 were 1.76-2.43 times higher than those of Lu527-4. Significant positive correlations between organic acids contents and Cd contents in plants were observed in both rice lines, except that malic acid was only highly relevant to Lu527-8, but not to Lu527-4. (2) Both composition and quantities of amino acids in root exudates changed a lot under Cd stress and this change differed in two rice lines. In control, four amino acids (glutamic acid, glycine, tyrosine and histidine) were detected in two rice lines. Under Cd stress, eight amino acids in Lu527-8 and seven amino acids in Lu527-4 could be detected, among which phenylalanine was only secreted by Lu527-8 and alanine, methionine and lysine were secreted by both rice lines. The contents of those four newly secreted amino acids from Lu527-8 increased significantly with the increase of Cd dose and each had a high-positive correlation with Cd contents, but the same change did not appear in Lu527-4. The difference between two rice lines in secretion of organic acids and amino acids may be related to their different Cd uptake properties. Copyright © 2017 Elsevier Inc. All rights reserved.

  13. Intraspecific variability in allelopathy of Heracleum mantegazzianum is linked to the metabolic profile of root exudates

    Czech Academy of Sciences Publication Activity Database

    Jandová, Kateřina; Dostál, Petr; Cajthaml, Tomáš; Kameník, Zdeněk

    2015-01-01

    Roč. 115, č. 5 (2015), s. 821-831 ISSN 0305-7364 R&D Projects: GA MŠk(CZ) EE2.3.30.0003; GA ČR GAP504/10/0132 Institutional support: RVO:67985939 ; RVO:61388971 Keywords : giant hogweed * root exudates * UHPLC–TOF-MS Subject RIV: EF - Botanics; EE - Microbiology, Virology (MBU-M) Impact factor: 3.982, year: 2015

  14. The variation of root exudates from the hyperaccumulator Sedum alfredii under cadmium stress: metabonomics analysis.

    Directory of Open Access Journals (Sweden)

    Qing Luo

    Full Text Available Hydroponic experiments were conducted to investigate the variation of root exudates from the hyperaccumulator Sedum alfredii under the stress of cadmium (Cd. S. alfredii was cultured for 4 days in the nutrient solution spiked with CdCl2 at concentrations of 0, 5, 10, 40, and 400 µM Cd after the pre-culture. The root exudates were collected and analyzed by GC-MS, and 62 compounds were identified. Of these compounds, the orthogonal partial least-squares discrimination analysis (OPLS-DA showed that there were a distinct difference among the root exudates with different Cd treatments and 20 compounds resulting in this difference were found out. Changing tendencies in the relative content of these 20 compounds under the different Cd treatments were analyzed. These results indicated that trehalose, erythritol, naphthalene, d-pinitol and n-octacosane might be closely related to the Cd stabilization, phosphoric acid, tetradecanoic acid, oxalic acid, threonic acid and glycine could be attributed to the Cd mobilization, and mannitol, oleic acid, 3-hydroxybutanoic acid, fructose, octacosanol and ribitol could copy well with the Cd stress.

  15. Exudation of fluorescent beta-carbolines from Oxalis tuberosa L roots.

    Science.gov (United States)

    Bais, Harsh Pal; Park, Sang-Wook; Stermitz, Frank R; Halligan, Kathleen M; Vivanco, Jorge M

    2002-11-01

    Root fluorescence is a phenomenon in which roots of seedlings fluoresce when irradiated with ultraviolet (UV) light. Soybean (Glycine max) and rye grass (Elymus glaucus) are the only plant species that have been reported to exhibit this occurrence in germinating seedling roots. The trait has been useful as a marker in genetic, tissue culture and diversity studies, and has facilitated selection of plants for breeding purposes. However, the biological significance of this occurrence in plants and other organisms is unknown. Here we report that the Andean tuber crop species Oxalis tuberosa, known as oca in the highlands of South America, secretes a fluorescent compound as part of its root exudates. The main fluorescent compounds were characterized as harmine (7-methoxy-1-methyl-beta-carboline) and harmaline (3, 4-dihydroharmine). We also detected endogenous root fluorescence in other plant species, including Arabidopsis thaliana and Phytolacca americana, a possible indication that this phenomenon is widespread within the plant kingdom.

  16. Affects N fertilization intensity and composition of root exudation from two plant species differing in their exploitation strategy?

    Science.gov (United States)

    Kotas, Petr; Kastovska, Eva

    2017-04-01

    The rhizosphere represents one of the most important hotspots of microbial activity in soil. As such, it controls soil element cycling and significantly contributes to important ecosystem processes like C and N sequestration. The close plant-microbe-soil interactions in the rhizosphere are mediated by the input of labile exudates into the surroundings of plant roots. Thus microbial performance is constrained by the intensity and composition of root exudation. However, it is poorly understood how closely root exudation corresponds with the plant metabolome and how it is related to plant traits and changing environmental conditions. To fill this gap, we determined the composition of the root metabolic pool and root exudates in two plant species differing in their exploitation type (conservative Carex acuta versus competitive Glyceria maxima) grown for two months in controlled conditions and treated weekly by two levels of foliar N fertilization. Based on previous studies, we knew that Glyceria has, compared to Carex, a lower tissue C:N ratio, higher photosynthetic rate, higher allocation belowground and also larger investment to exudation. Prior to extraction, the roots were cleaned by water and immediately frozen in liquid N2. The root exudates were collected from carefully cleaned roots of living plants encased in glass vials with water and subsequently lyophilised. Both sample types were silylated and analysed for their metabolic profiles using GC-MS/MS. Our results revealed that the metabolite content in root tissue (DW basis) of Glyceria was on average lower compared to Carex, but increased with fertilization, while the root tissue of Carex was characterized by significantly higher metabolite content in the low intensity fertilization treatment compared to both the control and high N fertilization intensity. In contrast, the amount of exuded compounds was much higher in Glyceria compared to Carex in the control plants, but decreased for Glyceria and increased

  17. Evaluation of putative allelochemicals in rice root exudates for their role in the suppression of arrowhead root growth.

    Science.gov (United States)

    Seal, Alexa N; Haig, Terry; Pratley, James E

    2004-08-01

    In previous studies, 15 putative allelopathic compounds detected in rice root exudates were quantified by GC/MS/MS. In this study, multiple regression analysis on these compounds determined that five selected phenolics, namely caffeic, p-hydroxybenzoic, vanillic, syringic, and p-coumaric acids, from rice exudates were best correlated with the observed allelopathic effect on arrowhead (Sagittaria montevidensis) root growth. Despite this positive association, determination of the phenolic acid dose-response curve established that the amount quantified in the exudates was much lower than the required threshold concentration for arrowhead inhibition. A similar dose-response curve resulted from a combination of all 15 quantified compounds. Significant differences between the amounts of trans-ferulic acid, abietic acid, and an indole also existed between allelopathic and non-allelopathic rice cultivars. The potential roles of these three compounds in rice allelopathy were examined by chemoassay. Overall, neither the addition of trans-ferulic acid nor 5-hydroxyindole-3-acetic acid to the phenolic mix significantly contributed to phytotoxicity, although at higher concentrations, trans-ferulic acid appeared to act antagonistically to the phytotoxic effects of the phenolic mix. The addition of abietic acid also decreased the inhibitory effect of the phenolic mix. These studies indicate that the compounds quantified are not directly responsible for the observed allelopathic response. It is possible that the amount of phenolic acids may be indirectly related to the chemicals finally responsible for the observed allelopathic effect.

  18. Phosphorus acquisition by citrate- and phytase-exuding Nicotiana tabacum plant mixtures depends on soil phosphorus availability and root intermingling.

    Science.gov (United States)

    Giles, Courtney D; Richardson, Alan E; Cade-Menun, Barbara J; Mezeli, Malika M; Brown, Lawrie K; Menezes-Blackburn, Daniel; Darch, Tegan; Blackwell, Martin Sa; Shand, Charles A; Stutter, Marc I; Wendler, Renate; Cooper, Patricia; Lumsdon, David G; Wearing, Catherine; Zhang, Hao; Haygarth, Philip M; George, Timothy S

    2018-03-02

    Citrate and phytase root exudates contribute to improved phosphorus (P) acquisition efficiency in Nicotiana tabacum (tobacco) when both exudates are produced in a P deficient soil. To test the importance of root intermingling in the interaction of citrate and phytase exudates, Nicotiana tabacum plant-lines with constitutive expression of heterologous citrate (Cit) or fungal phytase (Phy) exudation traits were grown under two root treatments (roots separated or intermingled) and in two soils with contrasting soil P availability. Complementarity of plant mixtures varying in citrate efflux rate and mobility of the expressed phytase in soil was determined based on plant biomass and P accumulation. Soil P composition was evaluated using solution 31 P NMR spectroscopy. In the soil with limited available P, positive complementarity occurred in Cit+Phy mixtures with roots intermingled. Root separation eliminated positive interactions in mixtures expressing the less mobile phytase (Aspergillus niger PhyA) whereas positive complementarity persisted in mixtures that expressed the more mobile phytase (Peniophora lycii PhyA). Soils from Cit+Phy mixtures contained less inorganic P and more organic P compared to monocultures. Exudate-specific strategies for the acquisition of soil P were most effective in P-limited soil and depended on citrate efflux rate and the relative mobility of the expressed phytase in soil. Plant growth and soil P utilization in plant systems with complementary exudation strategies are expected to be greatest where exudates persist in soil and are expressed synchronously in space and time. This article is protected by copyright. All rights reserved.

  19. The components of rice and watermelon root exudates and their effects on pathogenic fungus and watermelon defense.

    Science.gov (United States)

    Ren, Lixuan; Huo, Hongwei; Zhang, Fang; Hao, Wenya; Xiao, Liang; Dong, Caixia; Xu, Guohua

    2016-06-02

    Watermelon (Citrullus lanatus) is susceptible to wilt disease caused by the fungus Fusarium oxysporum f. sp niveum (FON). Intercropping management of watermelon/aerobic rice (Oryza sativa) alleviates watermelon wilt disease, because some unidentified component(s) in rice root exudates suppress FON sporulation and spore germination. Here, we show that the phenolic acid p-coumaric acid is present in rice root exudates only, and it inhibits FON spore germination and sporulation. We found that exogenously applied p-coumaric acid up-regulated the expression of ClPR3 in roots, as well as increased chitinase activity in leaves. Furthermore, exogenously applied p-coumaric acid increased β-1,3-glucanase activity in watermelon roots. By contrast, we found that ferulic acid was secreted by watermelon roots, but not by rice roots, and that it stimulated spore germination and sporulation of FON. Exogenous application of ferulic acid down-regulated ClPR3 expression and inhibited chitinase activity in watermelon leaves. Salicylic acid was detected in both watermelon and rice root exudates, which stimulated FON spore germination at low concentrations and suppressed spore germination at high concentrations. Exogenously applied salicylic acid did not alter ClPR3 expression, but did increase chitinase and β-1,3-glucanase activities in watermelon leaves. Together, our results show that the root exudates of phenolic acids were different between rice and watermelon, which lead to their special ecological roles on pathogenic fungus and watermelon defense.

  20. Plant-microbe rhizosphere interactions mediated by Rehmannia glutinosa root exudates under consecutive monoculture

    Science.gov (United States)

    Wu, Linkun; Wang, Juanying; Huang, Weimin; Wu, Hongmiao; Chen, Jun; Yang, Yanqiu; Zhang, Zhongyi; Lin, Wenxiong

    2015-10-01

    Under consecutive monoculture, the biomass and quality of Rehmannia glutinosa declines significantly. Consecutive monoculture of R. glutinosa in a four-year field trial led to significant growth inhibition. Most phenolic acids in root exudates had cumulative effects over time under sterile conditions, but these effects were not observed in the rhizosphere under monoculture conditions. It suggested soil microbes might be involved in the degradation and conversion of phenolic acids from the monocultured plants. T-RFLP and qPCR analysis demonstrated differences in both soil bacterial and fungal communities during monoculture. Prolonged monoculture significantly increased levels of Fusarium oxysporum, but decreased levels of Pseudomonas spp. Abundance of beneficial Pseudomonas spp. with antagonistic activity against F. oxysporum was lower in extended monoculture soils. Phenolic acid mixture at a ratio similar to that found in the rhizosphere could promote mycelial growth, sporulation, and toxin (3-Acetyldeoxynivalenol, 15-O-Acetyl-4-deoxynivalenol) production of pathogenic F. oxysporum while inhibiting growth of the beneficial Pseudomonas sp. W12. This study demonstrates that extended monoculture can alter the microbial community of the rhizosphere, leading to relatively fewer beneficial microorganisms and relatively more pathogenic and toxin-producing microorganisms, which is mediated by the root exudates.

  1. Low strigolactone root exudation: a novel mechanism of broomrape (Orobanche and Phelipanche spp.) resistance available for faba bean breeding.

    Science.gov (United States)

    Fernández-Aparicio, Mónica; Kisugi, Takaya; Xie, Xiaonan; Rubiales, Diego; Yoneyama, Koichi

    2014-07-23

    Faba bean yield is severely constrained in the Mediterranean region and Middle East by the parasitic weeds Orobanche crenata, O. foetida, and Phelipanche aegyptiaca. Seed germination of these weeds is triggered upon recognition of host root exudates. Only recently faba bean accessions have been identified with resistance based in low induction of parasitic seed germination, but the underlying mechanism was not identified. Strigolactones are a group of terpenoid lactones involved in the host recognition by parasitic plants. Our LC-MS/MS analysis of root exudates of the susceptible accession Prothabon detected orobanchol, orobanchyl acetate, and a novel germination stimulant. A time course analysis indicated that their concentration increased with plant age. However, low or undetectable amounts of these germination stimulants were detected in root exudates of the resistant lines Quijote and Navio at all plant ages. A time course analysis of seed germination induced by root exudates of each faba bean accession indicated important differences in the ability to stimulate parasitic germination. Results presented here show that resistance to parasitic weeds based on low strigolactone exudation does exist within faba bean germplasm. Therefore, selection for this trait is feasible in a breeding program. The remarkable fact that low induction of germination is similarly operative against O. crenata, O. foetida, and P. aegyptiaca reinforces the value of this resistance.

  2. Differential metabolic responses of Beauveria bassiana cultured in pupae extracts, root exudates and its interactions with insect and plant.

    Science.gov (United States)

    Luo, Feifei; Wang, Qian; Yin, Chunlin; Ge, Yinglu; Hu, Fenglin; Huang, Bo; Zhou, Hong; Bao, Guanhu; Wang, Bin; Lu, Ruili; Li, Zengzhi

    2015-09-01

    Beauveria bassiana is a kind of world-wide entomopathogenic fungus and can also colonize plant rhizosphere. Previous researches showed differential expression of genes when entomopathogenic fungi are cultured in insect or plant materials. However, so far there is no report on metabolic alterations of B. bassiana in the environments of insect or plant. The purpose of this paper is to address this problem. Herein, we first provide the metabolomic analysis of B. bassiana cultured in insect pupae extracts (derived from Euproctis pseudoconspersa and Bombyx mori, EPP and BMP), plant root exudates (derived from asparagus and carrot, ARE and CRE), distilled water and minimal media (MM), respectively. Principal components analysis (PCA) shows that mycelia cultured in pupae extracts and root exudates are evidently separated and individually separated from MM, which indicates that fungus accommodates to insect and plant environments by different metabolic regulation mechanisms. Subsequently, orthogonal projection on latent structure-discriminant analysis (OPLS-DA) identifies differential metabolites in fungus under three environments relative to MM. Hierarchical clustering analysis (HCA) is performed to cluster compounds based on biochemical relationships, showing that sphingolipids are increased in BMP but are decreased in EPP. This observation further implies that sphingolipid metabolism may be involved in the adaptation of fungus to different hosts. In the meantime, sphingolipids are significantly decreased in root exudates but they are not decreased in distilled water, suggesting that some components of the root exudates can suppress sphingolipid to down-regulate sphingolipid metabolism. Pathway analysis finds that fatty acid metabolism is maintained at high level but non-ribosomal peptides (NRP) synthesis is unaffected in mycelia cultured in pupae extracts. In contrast, fatty acid metabolism is not changed but NRP synthesis is high in mycelia cultured in root exudates

  3. Flavonoids and Strigolactones in Root Exudates as Signals in Symbiotic and Pathogenic Plant-Fungus Interactions

    Directory of Open Access Journals (Sweden)

    Horst Vierheilig

    2007-07-01

    Full Text Available Secondary plant compounds are important signals in several symbiotic and pathogenic plant-microbe interactions. The present review is limited to two groups of secondary plant compounds, flavonoids and strigolactones, which have been reported in root exudates. Data on flavonoids as signaling compounds are available from several symbiotic and pathogenic plant-microbe interactions, whereas only recently initial data on the role of strigolactones as plant signals in the arbuscular mycorrhizal symbiosis have been reported. Data from other plant-microbe interactions and strigolactones are not available yet. In the present article we are focusing on flavonoids in plant-fungalinteractions such as the arbuscular mycorrhizal (AM association and the signaling between different Fusarium species and plants. Moreover the role of strigolactones in the AM association is discussed and new data on the effect of strigolactones on fungi, apart from arbuscular mycorrhizal fungi (AMF, are provided.

  4. Proteogenomics data for deciphering Frankia coriariae interactions with root exudates from three host plants

    Directory of Open Access Journals (Sweden)

    Guylaine Miotello

    2017-10-01

    Full Text Available Frankia coriariae BMG5.1 cells were incubated with root exudates derived from compatible (Coriaria myrtifolia, incompatible (Alnus glutinosa and non-actinorhizal (Cucumis melo host plants. Bacteria cells and their exoproteomes were analyzed by high-throughput proteomics using a Q-Exactive HF high resolution tandem mass spectrometer incorporating an ultra-high-field orbitrap analyzer. MS/MS spectra were assigned with two protein sequence databases derived from the closely-related genomes from strains BMG5.1 andDg1, the Frankia symbiont of Datisca glomerata. The tandem mass spectrometry data accompanying the manuscript describing the database searches and comparative analysis (Ktari et al., 2017, doi.org/10.3389/fmicb.2017.00720 [1] have been deposited to the ProteomeXchange with identifiers PXD005979 (whole cell proteomes and PXD005980 (exoproteome data.

  5. Root exudates and leaf leachates of 19 medicinal plants of pakistan exhibit allelopathic potential

    International Nuclear Information System (INIS)

    Syed, S.; Ahmed, Z.I.; Razzaq, A.

    2014-01-01

    Laboratory experiments were conducted to evaluate the allelopathic potential of root exudates and leaf leachates of 19 medicinal plants commonly used in Pakistan by plant box and sandwich methods, respectively. In sandwich method, lettuce seedlings were grown with the dry leaf leachates of the selected plant species in a growing media at the rate of 5, 10 and 50 mg dish-1 in a completely randomized design with three replications. Their effects on hypocotyl and radicle growth of the lettuce were recorded as a percentage of untreated control. Data was subjected for analysis of variance and treatment means were compared by Tukey's HSD test at p<0.05. Results indicated that allelopathic effects of the leaf leachates of all selected plant species on the hypocotyl and radicle elongations of the lettuce varied significantly in all concentrations used in experiments. The hypocotyl growth of the lettuce seedlings was affected from promotion (6.71% inhibition) caused by Phlaris minor to inhibition (78.40%) by Withania somnifera. Both species suppressed the radicle length from 33.69-93.30%. Leachates of W. somnifera and Sarcococca saligna exhibited strong inhibitory results in a concentration dependant manner. After the growth period of 50 days, root exudates of S. saligna appeared most detrimental (78.00% inhibition) to radicle growth of the lettuce seedling followed by W. somnifera (75.00%) when tested by plant box method. The results presented can be utilized as benchmark information for further joint research on the elucidation of chemicals involved in the allelopathy in nature and in the development of new and potent bioherbicides to combat environmental risk. (author)

  6. Two mire species respond differently to enhanced ultraviolet-B radiation: effects on biomass allocation and root exudation

    DEFF Research Database (Denmark)

    Rinnan, Riikka Tiivi Mariisa; Gehrke, Carola; Michelsen, Anders

    2006-01-01

    •  Increased ultraviolet-B (UV-B) radiation arising from stratospheric ozone depletion may influence soil microbial communities via effects on plant carbon allocation and root exudation. •  Eriophorum angustifolium and Narthecium ossifragum plants, grown in peatland mesocosms consisting of Sphagnum...

  7. Compositional differences in simulated root exudates elicit a limited functional and compositional response in soil microbial communities.

    Science.gov (United States)

    Strickland, Michael S; McCulley, Rebecca L; Nelson, Jim A; Bradford, Mark A

    2015-01-01

    Inputs of low molecular weight carbon (LMW-C) to soil - primarily via root exudates- are expected to be a major driver of microbial activity and source of stable soil organic carbon. It is expected that variation in the type and composition of LMW-C entering soil will influence microbial community composition and function. If this is the case then short-term changes in LMW-C inputs may alter processes regulated by these communities. To determine if change in the composition of LMW-C inputs influences microbial community function and composition, we conducted a 90 day microcosm experiment whereby soils sourced from three different land covers (meadows, deciduous forests, and white pine stands) were amended, at low concentrations, with one of eight simulated root exudate treatments. Treatments included no addition of LMW-C, and the full factorial combination of glucose, glycine, and oxalic acid. After 90 days, we conducted a functional response assay and determined microbial composition via phospholipid fatty acid analysis. Whereas we noted a statistically significant effect of exudate treatments, this only accounted for ∼3% of the variation observed in function. In comparison, land cover and site explained ∼46 and ∼41% of the variation, respectively. This suggests that exudate composition has little influence on function compared to site/land cover specific factors. Supporting the finding that exudate effects were minor, we found that an absence of LMW-C elicited the greatest difference in function compared to those treatments receiving any LMW-C. Additionally, exudate treatments did not alter microbial community composition and observable differences were instead due to land cover. These results confirm the strong effects of land cover/site legacies on soil microbial communities. In contrast, short-term changes in exudate composition, at meaningful concentrations, may have little impact on microbial function and composition.

  8. Benzoxazinoids in root exudates of maize attract Pseudomonas putida to the rhizosphere.

    Directory of Open Access Journals (Sweden)

    Andrew L Neal

    Full Text Available Benzoxazinoids, such as 2,4-dihydroxy-7-methoxy-2H-1,4-benzoxazin-3(4H-one (DIMBOA, are secondary metabolites in grasses. In addition to their function in plant defence against pests and diseases above-ground, benzoxazinoids (BXs have also been implicated in defence below-ground, where they can exert allelochemical or antimicrobial activities. We have studied the impact of BXs on the interaction between maize and Pseudomonas putida KT2440, a competitive coloniser of the maize rhizosphere with plant-beneficial traits. Chromatographic analyses revealed that DIMBOA is the main BX compound in root exudates of maize. In vitro analysis of DIMBOA stability indicated that KT2440 tolerance of DIMBOA is based on metabolism-dependent breakdown of this BX compound. Transcriptome analysis of DIMBOA-exposed P. putida identified increased transcription of genes controlling benzoate catabolism and chemotaxis. Chemotaxis assays confirmed motility of P. putida towards DIMBOA. Moreover, colonisation essays in soil with Green Fluorescent Protein (GFP-expressing P. putida showed that DIMBOA-producing roots of wild-type maize attract significantly higher numbers of P. putida cells than roots of the DIMBOA-deficient bx1 mutant. Our results demonstrate a central role for DIMBOA as a below-ground semiochemical for recruitment of plant-beneficial rhizobacteria during the relatively young and vulnerable growth stages of maize.

  9. Early Lotus japonicus root transcriptomic responses to symbiotic and pathogenic fungal exudates

    Directory of Open Access Journals (Sweden)

    Marco eGiovannetti

    2015-06-01

    Full Text Available The objective of this study is to evaluate Lotus japonicus transcriptomic responses to arbuscular mycorrhizal (AM germinated spore exudates (GSE, responsible for activating nuclear Ca2+ spiking in plant root epidermis. A microarray experiment was performed comparing gene expression in Lotus rootlets treated with GSE or water after 24 h and 48 h. The transcriptional pattern of selected genes that resulted to be regulated in the array was further evaluated upon different treatments and timings. In particular, Lotus rootlets were treated with: GSE from the pathogenic fungus Colletotrichum trifolii; short chitin oligomers (acknowledged AM fungal signals and long chitin oligomers (as activators of pathogenic responses. This experimental set up has revealed that AM GSE generates a strong transcriptomic response in Lotus roots with an extensive defense-related response after 24 hours and a subsequent downregulation after 48 hours. A similar subset of defense-related genes resulted to be upregulated also upon treatment with C. trifolii GSE, although with an opposite trend. Surprisingly, long chitin oligomers activated both defense-like and symbiosis-related genes. Among the genes regulated in the microarray, promoter-GUS assay showed that LjMATE1 activates in epidermal cells and root hairs.

  10. Bacteria from Wheat and Cucurbit Plant Roots Metabolize PAHs and Aromatic Root Exudates: Implications for Rhizodegradation

    DEFF Research Database (Denmark)

    Ely, Cairn S; Smets, Barth F.

    2017-01-01

    The chemical interaction between plants and bacteria in the root zone can lead to soil decontamination. Bacteria which degrade PAHs have been isolated from the rhizospheres of plant species with varied biological traits, however, it is not known what phytochemicals promote contaminant degradation....... One monocot and two dicotyledon plants were grown in PAH-contaminated soil from a manufactured gas plant (MGP) site. A phytotoxicity assay confirmed greater soil decontamination in rhizospheres when compared to bulk soil controls. Bacteria were isolated from plant roots (rhizobacteria) and selected...

  11. Bacteria from Wheat and Cucurbit Plant Roots Metabolize PAHs and Aromatic Root Exudates: Implications for Rhizodegradation

    DEFF Research Database (Denmark)

    Ely, Cairn S; Smets, Barth F.

    2017-01-01

    The chemical interaction between plants and bacteria in the root zone can lead to soil decontamination. Bacteria which degrade PAHs have been isolated from the rhizospheres of plant species with varied biological traits, however, it is not known what phytochemicals promote contaminant degradation...

  12. Effects of Selected Root Exudate Components on Nitrogen Removal and Development of Denitrifying Bacteria in Constructed Wetlands

    Directory of Open Access Journals (Sweden)

    Hailu Wu

    2017-06-01

    Full Text Available Root exudates, particularly low molecular weight carbon (LMWC substrates, are major drivers of bacterial diversity and activity in the rhizosphere environment. However, it is not well understood how specific LMWC compounds—such as organic acids, soluble sugars, and amino acids—influence the community structures of denitrifying bacteria or if there are specific functions of LMWC substrates that preferentially respond to nitrogen (N removal in constructed wetlands (CWs. To address these knowledge gaps, we added mixtures of artificial exudates to CW microcosms containing N pollutant. N removal efficiency was observed over a 48-h experimental period, and at the end of the experiment, DNA was extracted from microbial samples for assessment of the bacterial community. The removal efficiencies of TN for the exudates treatments were higher than for control groups by 47.1–58.67%. Organic acid and soluble sugar treatments increased N removal, while amino acids were negative to N removal. The microbial community was changed when artificial exudates were added, but there were no significant relationships between LMWC compounds and bacterial community composition. These results indicate that although the responses of community structures of denitrifying bacteria to LMWC additions are still uncertain, there is evidence for N removal in response to exudate additions across LMWC types.

  13. Is the mineralisation response to root exudation controlled by the microbial stoichiometric demand in subarctic soils?

    Science.gov (United States)

    Rousk, Johannes; Hicks, Lettice; Leizeaga, Ainara; Michelsen, Anders; Rousk, Kathrin

    2017-04-01

    Climate change will expose arctic and subarctic systems to warming and a shift towards plant communities with more rhizosphere labile C input. Labile C can also increase the rate of loss of native soil organic matter (SOM); a phenomenon termed 'priming'. We investigated how warming (+1.1˚ C over ambient using open top chambers) and the addition of plant litter (90 g m-2 y-1) or organic nitrogen (N) (fungal fruit bodies; 90 g m-2 y-1) in the Subarctic influenced the susceptibility of SOM mineralisation to priming, and its microbial underpinnings. Root exudation were simulated with the addition of labile organic matter both in the form of only labile C (13C-glucose) or in the form of labile C and N (13C-alanine). We hypothesized that labile C would induce a higher mineralization of N than C sourced from SOM ("N mining"); a response unrelated to microbial growth responses. We also hypothesized that the N mining effect would be more pronounced in climate change simulation treatments of higher C/N (plant litter) than treatments with lower C/N (fungal fruitbodies and warming), with the control treatments intermediate. We also hypothesized that the addition of labile C and N would not result in selective N mining, but instead coupled responses of C and N mineralisation sourced from SOM; a response that would coincide with stimulated microbial growth responses. Labile C appeared to inhibit the mineralisation of C from SOM by up to 60% within hours. In contrast, the mineralisation of N from SOM was stimulated by up to 300%. These responses occurred rapidly and were unrelated to microbial successional dynamics, suggesting catabolic responses. Considered separately, the labile-C inhibited C mineralisation is compatible with previously reported findings termed 'preferential substrate utilisation' or 'negative apparent priming', while the stimulated N mineralisation responses echo recent reports of 'real priming' of SOM mineralisation. However, C and N mineralisation responses

  14. The mechanisms of root exudates of maize in improvement of iron nutrition of peanut in peanut/maize intercropping system by 14C tracer technique

    International Nuclear Information System (INIS)

    Zuo Yuanmei; Chen Qing; Zhang Fusuo

    2004-01-01

    The related mechanisms of root exudates of maize in improvement iron nutrition of peanut intercropped with maize was investigated by 14 C tracer technique. Neighboring roots between maize and peanut were separated by a 30 μm nylon net, the iron nutrition of peanut was also improved just like normal intercropping of maize and peanut. The results proved that root exudates of maize played an important role in improvement iron nutrition of peanut. The photosynthesis carbohydrate of maize could exuded into the rhizosphere of peanut and transfer into shoot and root of peanut in intercropping system. Root exudates of maize could increased efficiency of iron in soil and improved iron utilization of peanut

  15. Diversity and function of the microbial community on anodes of sediment microbial fuel cells fueled by root exudates

    Energy Technology Data Exchange (ETDEWEB)

    Cabezas da Rosa, Angela

    2010-11-26

    Anode microbial communities are essential for current production in microbial fuel cells. Anode reducing bacteria are capable of using the anode as final electron acceptor in their respiratory chain. The electrons delivered to the anode travel through a circuit to the cathode where they reduce oxygen to water generating an electric current. A novel type of sediment microbial fuel cell (SMFC) harvest energy from photosynthetically derived compounds released through the roots. Nothing is known about anode microbial communities of this type of microbial fuel cell. This work consists of three parts. The first part focuses on the study of bacterial and archaeal community compositions on anodes of SMFCs fueled by rice root exudates. By using terminal restriction fragment length polymorphism (T-RFLP), a profiling technique, and cloning / sequencing of 16S rRNA, we determined that the support type used for the plant (vermiculite, potting soil or rice field soil) is an important factor determining the composition of the microbial community. Finally, by comparing microbial communities of current producing anodes and non-current producing controls we determined that Desulfobulbus- and Geobacter-related populations were probably most important for current production in potting soil and rice field soil SMFCs, respectively. However, {delta}-proteobacterial Anaeromyxobacter spp., unclassified {delta}-proteobacteria and Anaerolineae were also part of the anode biofilm in rice field soil SMFCs and these populations might also play a role in current production. Moreover, distinct clusters of Geobacter and Anaeromyxobacter populations were stimulated by rice root exudates. Regarding Archaea, uncultured Euryarchaea were abundant on anodes of potting soil SMFCs indicating a potential role in current production. In both, rice field soil and potting soil SMFCs, a decrease of Methanosaeta, an acetotrophic methanogen, was detected on current producing anodes. In the second part we focused

  16. Increased root exudation of 14C-compounds by sorghum seedlings inoculated with nitrogen-fixing bacteria

    International Nuclear Information System (INIS)

    Lee, K.J.; Gaskins, M.H.

    1982-01-01

    Organic components leaked from Sorghum bicolor seedlings ('root exudates') were examined by recovering 14 C labelled compounds from root solutions of seedlings inoculated with Azospirillum brasilense, Azotobacter vinelandii or Klebsiella pneumoniae nif-. Up to 3.5% of the total 14 C recovered from shoots, roots, and nutrient solutions was found in the root solutions. Inoculation with Azospirillum and Azotobacter increased the amounts of 14 C and decreased the amounts of carbohydrates in the root solutions. When sucrose was added as a carbon source for the bacteria, the increase of 14 C in the solutions did not occur. Quantities of 14 C found in the root solutions were proportional to amounts of mineral nitrogen supplied to the plants. Bacterial growth also was proportional to nitrogen levels. When sorghum plants were grown in soil and labelled with 14 CO 2 , about 15% of the total 14 C recovered within 48 hours exposure was found in soil leachates. (orig.)

  17. Benzo[a]pyrene co-metabolism in the presence of plant root extracts and exudates: Implications for phytoremediation

    Energy Technology Data Exchange (ETDEWEB)

    Rentz, Jeremy A [Civil and Environmental Engineering, University of Iowa, Iowa City, IA 52242 (United States); Alvarez, Pedro J.J. [Civil and Environmental Engineering, Rice University, Houston, TX 77251 (United States); Schnoor, Jerald L [Civil and Environmental Engineering, University of Iowa, Iowa City, IA 52242 (United States)

    2005-08-15

    Benzo[a]pyrene, a high molecular weight (HMW) polycyclic aromatic hydrocarbon (PAH) was removed from solution by Sphingomonas yanoikuyae JAR02 while growing on root products as a primary carbon and energy source. Plant root extracts of osage orange (Maclura pomifera), hybrid willow (Salix albaxmatsudana), or kou (Cordia subcordata), or plant root exudates of white mulberry (Morus alba) supported 15-20% benzo[a]pyrene removal over 24 h that was similar to a succinate grown culture and an unfed acetonitrile control. No differences were observed between the different root products tested. Mineralization of {sup 14}C-7-benzo[a]pyrene by S. yanoikuyae JAR02 yielded 0.2 to 0.3% {sup 14}CO{sub 2} when grown with plant root products. Collectively, these observations were consistent with field observations of enhanced phytoremediation of HMW PAH and corroborated the hypothesis that co-metabolism may be a plant/microbe interaction important to rhizoremediation. However, degradation and mineralization was much less for root product-exposed cultures than salicylate-induced cultures, and suggested the rhizosphere may not be an optimal environment for HMW PAH degradation by Sphingomonas yanoikuyae JAR02. - Bacterial benzo[a]pyrene cometabolism, a plant-microbe interaction affecting polycyclic aromatic hydrocarbon phytoremediation was demonstrated with Sphingomonas yanoikuyae JAR02 that utilized plant root extracts and exudates as primary substrates.

  18. Benzo[a]pyrene co-metabolism in the presence of plant root extracts and exudates: Implications for phytoremediation

    International Nuclear Information System (INIS)

    Rentz, Jeremy A.; Alvarez, Pedro J.J.; Schnoor, Jerald L.

    2005-01-01

    Benzo[a]pyrene, a high molecular weight (HMW) polycyclic aromatic hydrocarbon (PAH) was removed from solution by Sphingomonas yanoikuyae JAR02 while growing on root products as a primary carbon and energy source. Plant root extracts of osage orange (Maclura pomifera), hybrid willow (Salix albaxmatsudana), or kou (Cordia subcordata), or plant root exudates of white mulberry (Morus alba) supported 15-20% benzo[a]pyrene removal over 24 h that was similar to a succinate grown culture and an unfed acetonitrile control. No differences were observed between the different root products tested. Mineralization of 14 C-7-benzo[a]pyrene by S. yanoikuyae JAR02 yielded 0.2 to 0.3% 14 CO 2 when grown with plant root products. Collectively, these observations were consistent with field observations of enhanced phytoremediation of HMW PAH and corroborated the hypothesis that co-metabolism may be a plant/microbe interaction important to rhizoremediation. However, degradation and mineralization was much less for root product-exposed cultures than salicylate-induced cultures, and suggested the rhizosphere may not be an optimal environment for HMW PAH degradation by Sphingomonas yanoikuyae JAR02. - Bacterial benzo[a]pyrene cometabolism, a plant-microbe interaction affecting polycyclic aromatic hydrocarbon phytoremediation was demonstrated with Sphingomonas yanoikuyae JAR02 that utilized plant root extracts and exudates as primary substrates

  19. [Quantitive study of interleukin 1beta in periapical exudates of chronic periapical periodontitis in the course of root canal therapy].

    Science.gov (United States)

    Yan, Pei-fang; Liang, Jing-ping; Chen, Wei-min; Gu, Shen-sheng

    2007-06-01

    To evaluate the relationship between IL-1beta and clinical findings of chronic apical periodontitis and to explore the function of IL-1beta during the endodontic interappointment flare-ups. Periapical exudates samples were obtained from 19 teeth suffering from endodontic flare-ups after root canal preparation and 20 teeth without any symptoms and signs at the second visit after root canal preparation. The levels of IL-1beta were determined by ELISA and the data was analyzed by SAS6.12 software package. Significantly higher levels of IL-1beta were found in periapical exudates from teeth suffering from endodontic flare-ups than that before canal preparation(Pendodontic therapy if there were no symptom at the second visit (Pendodontic interappointment flare-up.

  20. The dual effects of root-cap exudates on nematodes: from quiescence in plant-parasitic nematodes to frenzy in entomopathogenic nematodes.

    Science.gov (United States)

    Hiltpold, Ivan; Jaffuel, Geoffrey; Turlings, Ted C J

    2015-02-01

    To defend themselves against herbivores and pathogens, plants produce numerous secondary metabolites, either constitutively or de novo in response to attacks. An intriguing constitutive example is the exudate produced by certain root-cap cells that can induce a state of reversible quiescence in plant-parasitic nematodes, thereby providing protection against these antagonists. The effect of such root exudates on beneficial entomopathogenic nematodes (EPNs) remains unclear, but could potentially impair their use in pest management programmes. We therefore tested how the exudates secreted by green pea (Pisum sativum) root caps affect four commercial EPN species. The exudates induced reversible quiescence in all EPN species tested. Quiescence levels varied with the green pea cultivars tested. Notably, after storage in root exudate, EPN performance traits were maintained over time, whereas performances of EPNs stored in water rapidly declined. In sharp contrast to high concentrations, lower concentrations of the exudate resulted in a significant increase in EPN activity and infectiousness, but still reduced the activity of two plant-parasitic nematode species. Our study suggests a finely tuned dual bioactivity of the exudate from green pea root caps. Appropriately formulated, it can favour long-term storage of EPNs and boost their infectiousness, while it may also be used to protect plants from plant-parasitic nematodes. © The Author 2014. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  1. Compositional differences in simulated root exudates elicit a limited functional and compositional response in soil microbial communities

    Directory of Open Access Journals (Sweden)

    Michael S Strickland

    2015-08-01

    Full Text Available Inputs of low molecular weight carbon (LMW-C to soil −primarily via root exudates− are expected to be a major driver of microbial activity and source of stable soil organic carbon. It is expected that variation in the type and composition of LMW-C entering soil will influence microbial community composition and function. If this is the case then short-term changes in LMW-C inputs may alter processes regulated by these communities. To determine if change in the composition of LMW-C inputs influences microbial community function and composition, we conducted a 90 day microcosm experiment whereby soils sourced from three different land covers (meadows, deciduous forests, and white pine stands were amended, at low concentrations, with one of eight simulated root exudate treatments. Treatments included no addition of LMW-C, and the full factorial combination of glucose, glycine, and oxalic acid. After 90 days, we conducted a functional response assay and determined microbial composition via phospholipid fatty acid analysis. Whereas we noted a statistically significant effect of exudate treatments, this only accounted for ~3% of the variation observed in function. In comparison, land cover and site explained ~46 and ~41% of the variation, respectively. This suggests that exudate composition has little influence on function

  2. Regulation of root morphogenesis in arbuscular mycorrhizae: what role do fungal exudates, phosphate, sugars and hormones play in lateral root formation?

    Science.gov (United States)

    Fusconi, Anna

    2014-01-01

    Background Arbuscular mycorrhizae (AMs) form a widespread root–fungus symbiosis that improves plant phosphate (Pi) acquisition and modifies the physiology and development of host plants. Increased branching is recognized as a general feature of AM roots, and has been interpreted as a means of increasing suitable sites for colonization. Fungal exudates, which are involved in the dialogue between AM fungi and their host during the pre-colonization phase, play a well-documented role in lateral root (LR) formation. In addition, the increased Pi content of AM plants, in relation to Pi-starved controls, as well as changes in the delivery of carbohydrates to the roots and modulation of phytohormone concentration, transport and sensitivity, are probably involved in increasing root system branching. Scope This review discusses the possible causes of increased branching in AM plants. The differential root responses to Pi, sugars and hormones of potential AM host species are also highlighted and discussed in comparison with those of the non-host Arabidopsis thaliana. Conclusions Fungal exudates are probably the main compounds regulating AM root morphogenesis during the first colonization steps, while a complex network of interactions governs root development in established AMs. Colonization and high Pi act synergistically to increase root branching, and sugar transport towards the arbusculated cells may contribute to LR formation. In addition, AM colonization and high Pi generally increase auxin and cytokinin and decrease ethylene and strigolactone levels. With the exception of cytokinins, which seem to regulate mainly the root:shoot biomass ratio, these hormones play a leading role in governing root morphogenesis, with strigolactones and ethylene blocking LR formation in the non-colonized, Pi-starved plants, and auxin inducing them in colonized plants, or in plants grown under high Pi conditions. PMID:24227446

  3. Quantitative and qualitative effects of phosphorus on extracts and exudates of sudangrass roots in relation to vesicular-arbuscular mycorrhiza formation.

    Science.gov (United States)

    Schwab, S M; Menge, J A; Leonard, R T

    1983-11-01

    A comparison was made of water-soluble root exudates and extracts of Sorghum vulgare Pers. grown under two levels of P nutrition. An increase in P nutrition significantly decreased the concentration of carbohydrates, carboxylic acids, and amino acids in exudates, and decreased the concentration of carboxylic acids in extracts. Higher P did not affect the relative proportions of specific carboxylic acids and had little effect on proportions of specific amino acids in both extracts and exudates. Phosphorus amendment resulted in an increase in the relative proportion of arabinose and a decrease in the proportion of fructose in exudates, but did not have a large effect on the proportion of individual sugars in extracts. The proportions of specific carbohydrates, carboxylic acids, and amino acids varied between exudates and extracts. Therefore, the quantity and composition of root extracts may not be a reliable predictor of the availability of substrate for symbiotic vesicular-arbuscular mycorrhizal fungi. Comparisons of the rate of leakage of compounds from roots with the growth rate of vesicular-arbuscular mycorrhizal fungi suggest that the fungus must either be capable of using a variety of organic substrates for growth, or be capable of inducing a much higher rate of movement of specific organic compounds across root cell membranes than occurs through passive exudation as measured in this study.

  4. Modeling Root Exudation, Priming and Protection in Soil Carbon Responses to Elevated CO2 from Ecosystem to Global Scales

    Science.gov (United States)

    Sulman, B. N.; Phillips, R.; Shevliakova, E.; Oishi, A. C.; Pacala, S. W.

    2014-12-01

    The sensitivity of soil organic carbon (SOC) to changing environmental conditions represents a critical uncertainty in coupled carbon cycle-climate models. Much of this uncertainty arises from our limited understanding of the extent to which plants induce SOC losses (through accelerated decomposition or "priming") or promote SOC gains (via stabilization through physico-chemical protection). We developed a new SOC model, "Carbon, Organisms, Rhizosphere and Protection in the Soil Environment" (CORPSE), to examine the net effect of priming and protection in response to rising atmospheric CO2, and conducted simulations of rhizosphere priming effects at both ecosystem and global scales. At the ecosystem scale, the model successfully captured and explained disparate SOC responses at the Duke and Oak Ridge free-air CO2 enrichment (FACE) experiments. We show that stabilization of "new" carbon in protected SOC pools may equal or exceed microbial priming of "old" SOC in ecosystems with readily decomposable litter (e.g. Oak Ridge). In contrast, carbon losses owing to priming dominate the net SOC response in ecosystems with more resistant litters (e.g. Duke). For global simulations, the model was fully integrated into the Geophysical Fluid Dynamics Laboratory (GFDL) land model LM3. Globally, priming effects driven by enhanced root exudation and expansion of the rhizosphere reduced SOC storage in the majority of terrestrial areas, partially counterbalancing SOC gains from the enhanced ecosystem productivity driven by CO2 fertilization. Collectively, our results suggest that SOC stocks globally depend not only on temperature and moisture, but also on vegetation responses to environmental changes, and that protected C may provide an important constraint on priming effects.

  5. VARIATION IN RHIZOBIUM GROWTH DUE TO SEED AND ROOT EXUDATES RELEASED FROM GAMMA IRRADIATED GLYCINE MAX SEEDS

    International Nuclear Information System (INIS)

    KAMEL, H.A.; ASKER, M.M.S

    2008-01-01

    In this study, seeds of Glycine max Giza 122 were irradiated with gamma rays from 60 Co source at various doses (10 to 200 Gy), sterilized and soaked into an aerated solution of CaSO 4 (1 mmol and pH 6.5). The capacities of the released seed exudates (SEs) and root exudates (REs) to promote Rhizobium leguminosarum growth were investigated as well as biochemical analysis of the exudates was carried out. SE of both control and gamma irradiated seeds resulted in a higher Rhizobium population and polysaccharide production than RE. Relative to control, the highly effective doses in Rhizobium growth and polysaccharide production were 25 and 200 Gy; the former was a promoter while the later was an inhibitor. HPLC analysis of soluble carbohydrates revealed the presence of glucose (Glu), rhamnose (Rha) and fructose (Fru) in the SE and RE. Protein content in SE was lower than that in RE; the highest values were due to 10 Gy and 25 Gy in SE and RE, respectively. Free amino acids content in SE was increased up to 25 Gy then decreased while RE was increased by increasing gamma doses from 10 to 200 Gy

  6. Rhizoctonia solani and Bacterial Inoculants Stimulate Root Exudation of Antifungal Compounds in Lettuce in a Soil-Type Specific Manner

    Directory of Open Access Journals (Sweden)

    Saskia Windisch

    2017-06-01

    Full Text Available Previous studies conducted on a unique field site comprising three contrasting soils (diluvial sand DS, alluvial loam AL, loess loam LL under identical cropping history, demonstrated soil type-dependent differences in biocontrol efficiency against Rhizoctonia solani-induced bottom rot disease in lettuce by two bacterial inoculants (Pseudomonas jessenii RU47 and Serratia plymuthica 3Re-4-18. Disease severity declined in the order DS > AL > LL. These differences were confirmed under controlled conditions, using the same soils in minirhizotron experiments. Gas chromatography-mass spectrometry (GC-MS profiling of rhizosphere soil solutions revealed benzoic and lauric acids as antifungal compounds; previously identified in root exudates of lettuce. Pathogen inoculation and pre-inoculation with bacterial inoculants significantly increased the release of antifungal root exudates in a soil type-specific manner; with the highest absolute levels detected on the least-affected LL soil. Soil type-dependent differences were also recorded for the biocontrol effects of the two bacterial inoculants; showing the highest efficiency after double-inoculation on the AL soil. However, this was associated with a reduction of shoot growth and root hair development and a limited micronutrient status of the host plants. Obviously, disease severity and the expression of biocontrol effects are influenced by soil properties with potential impact on reproducibility of practical applications.

  7. Root-exuded acid phosphatase and 32Pi-uptake kinetics of wheat, rye and triticale under phosphorus starvation

    International Nuclear Information System (INIS)

    Pandey, Renu

    2006-01-01

    A nutrient culture experiment was conducted with cereal species viz., wheat (Triticum aestivum L.) cv. PBW-343), rye (Secale cereale L cv. R-308) and triticale (Triticale octoploide L. cv. DT-46), a hybrid of wheat and rye, to examine the genetic variation in root-exuded acid phosphatase (ACPase) activity and kinetics of 32 Pi-uptake under P deficient condition. The ACPase activity was assayed in the extract (intra-) and on surface (extra-cellular) or root, using p-nitrophenyl phosphate as substrate. Significantly higher ACPase activity was observed in wheat followed by rye and triticale both on the root surface and in root extract. In general, root surface ACPase activity was 2.2-fold higher than that in root extract. A strong correlation (r 2 = 0.87**) between extra and intra-cellular ACPase activity was observed. In terms of kinetic parameters, it was observed that 32 Pi uptake and I max values were significantly higher in rye while C min and K m were lowest compared to wheat and triticale. The dry weights of shoot, root and total plant were significantly higher in rye compared to wheat and triticale. Rye also had higher amount of total plant P content The superiority of rye over wheat and triticale in P uptake was observed mainly due to efficient Pi-uptake system, which needs further studies to ascertain the enhancement of Pi-induced high-affinity P transporter in these cereals. (author)

  8. Increased root exudation of /sup 14/C-compounds by sorghum seedlings inoculated with nitrogen-fixing bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Lee, K.J. (Institute of Forest Genetics, Suweon (Republic of Korea)); Gaskins, M.H. (Florida Univ., Gainesville (USA). Dept. of Agriculture)

    1982-01-01

    Organic components leaked from Sorghum bicolor seedlings ('root exudates') were examined by recovering /sup 14/C labelled compounds from root solutions of seedlings inoculated with Azospirillum brasilense, Azotobacter vinelandii or Klebsiella pneumoniae nif-. Up to 3.5% of the total /sup 14/C recovered from shoots, roots, and nutrient solutions was found in the root solutions. Inoculation with Azospirillum and Azotobacter increased the amounts of /sup 14/C and decreased the amounts of carbohydrates in the root solutions. When sucrose was added as a carbon source for the bacteria, the increase of /sup 14/C in the solutions did not occur. Quantities of /sup 14/C found in the root solutions were proportional to amounts of mineral nitrogen supplied to the plants. Bacterial growth also was proportional to nitrogen levels. When sorghum plants were grown in soil and labelled with /sup 14/CO/sub 2/, about 15% of the total /sup 14/C recovered within 48 hours exposure was found in soil leachates.

  9. 14CO2 labeling: a reliable technique for rapid measurement of total root exudation capacity and vascular sap flow in crops

    International Nuclear Information System (INIS)

    Singh, Bhupinder; Ahuja, Sumedha; Pandey, Renu; Singhal, R.K.

    2014-01-01

    Ability of roots to release organic compounds in its rhizosphere is known to improve plant available nutrients and reduces heavy metal toxicity by immobilization. It is regarded as an important determinant of micro nutrient deficiency tolerance in plants. Uptake of nutrients and translocation of photoassimilates, on the other hand are governed by the strength of the transpiration stream and sink demand respectively. Measurement of vascular sap flow, thus, is critical for understanding of the translocation efficiency and consequently the sink demand that keeps changing during the crop growth cycle. Measurement of the root exudation capacity and the vascular sap flow is cumbersome and time consuming. Since, the exudates released by the roots and the photosynthates translocated between the source and the sink are essentially carbon compounds, use of labeled carbon as tag could potentially be exploited for a rapid and reliable measurement of exudation and vascular sap flow in crop plants. We report here the experimental results involving 14 C labeling of groundnut, a legume crop, as 14 CO 2 generated by acidification of sodium bicarbonate. An additional factor of seed gamma irradiation was used to generate variability in the root exudation and the sap flow. The 14 C release by the roots was compared against the 14 C transport in the vascular sap. An experimental hypothesis that a higher 14 C level in the vascular sap would indicate a higher root release of carbon by the roots into the rhizosphere was verified. (author)

  10. The role of organic acids exuded from roots in phosphorus nutrition and aluminium tolerance in acidic soils

    Energy Technology Data Exchange (ETDEWEB)

    Hocking, P J; Randall, P J; Delhaize, E [CSIRO Plant Industry, Canberra (Australia); Keerthisinghe, G [International Atomic Energy Agency, Vienna (Austria)

    2000-06-01

    Soil acidity is a major problem of large areas of arable land on a global scale. Many acid soils are low in plant-available phosphorus (P) or are highly P-fixing, resulting in poor plant growth. In addition, aluminium (Al) is soluble in acid soils in the toxic Al{sup 3+} form, which also reduces plant growth. There is considerable evidence that both P deficiency and exposure to Al{sup 3+} stimulate the efflux of organic acids from roots of a range of species. Organic acids such as citrate, malate and oxalate are able to desorb or solubilise fixed soil P, making it available for plant uptake. Organic acids also chelate Al{sup 3+} to render it non-toxic, and are, therefore, involved in Al tolerance mechanisms. In this review, we discuss the literature on the role of organic acids exuded from roots in improving plant P uptake and Al-tolerance in acid soils. Research is now attempting to understand how P deficiency or exposure to Al{sup 3+} activates or induces organic acid efflux at the molecular level, with the aim of improving P acquisition and Al tolerance by conventional plant breeding and by genetic engineering. At the agronomic level, it is desirable that existing crop and pasture plants with enhanced soil-P uptake and tolerance to Al due to organic acid exudation are integrated into farming systems. (author)

  11. The role of organic acids exuded from roots in phosphorus nutrition and aluminium tolerance in acidic soils

    International Nuclear Information System (INIS)

    Hocking, P.J.; Randall, P.J.; Delhaize, E.; Keerthisinghe, G.

    2000-01-01

    Soil acidity is a major problem of large areas of arable land on a global scale. Many acid soils are low in plant-available phosphorus (P) or are highly P-fixing, resulting in poor plant growth. In addition, aluminium (Al) is soluble in acid soils in the toxic Al 3+ form, which also reduces plant growth. There is considerable evidence that both P deficiency and exposure to Al 3+ stimulate the efflux of organic acids from roots of a range of species. Organic acids such as citrate, malate and oxalate are able to desorb or solubilise fixed soil P, making it available for plant uptake. Organic acids also chelate Al 3+ to render it non-toxic, and are, therefore, involved in Al tolerance mechanisms. In this review, we discuss the literature on the role of organic acids exuded from roots in improving plant P uptake and Al-tolerance in acid soils. Research is now attempting to understand how P deficiency or exposure to Al 3+ activates or induces organic acid efflux at the molecular level, with the aim of improving P acquisition and Al tolerance by conventional plant breeding and by genetic engineering. At the agronomic level, it is desirable that existing crop and pasture plants with enhanced soil-P uptake and tolerance to Al due to organic acid exudation are integrated into farming systems. (author)

  12. Organic acid compounds in root exudation of Moso Bamboo (Phyllostachys pubescens) and its bioactivity as affected by heavy metals.

    Science.gov (United States)

    Chen, Junren; Shafi, Mohammad; Wang, Ying; Wu, Jiasen; Ye, Zhengqian; Liu, Chen; Zhong, Bin; Guo, Hua; He, Lizhi; Liu, Dan

    2016-10-01

    Moso bamboo (Phyllostachys pubescens) has great potential as phytoremediation material in soil contaminated by heavy metals. A hydroponics experiment was conducted to determine organic acid compounds of root exudates of lead- (Pb), zinc- (Zn), copper- (Cu), and cadmium (Cd)-tolerant of Moso bamboo. Plants were grown in nutrients solution which included Pb, Zn, Cu, and Cd applied as Pb(NO 3 ) 2 (200 μM), ZnSO 4 ·7H 2 O (100 μM), CuSO 4 ·5H 2 O (25 μM), and CdCl 2 (10 μM), respectively. Oxalic acid and malic acid were detected in all treatments. Lactic acid was observed in Cu, Cd, and control treatments. The oxalic was the main organic acid exudated by Moso bamboo. In the sand culture experiment, the Moso bamboo significantly activated carbonate heavy metals under activation of roots. The concentration of water-soluble metals (except Pb) in sand were significantly increased as compared with control. Organic acids (1 mM mixed) were used due to its effect on the soil adsorption of heavy metals. After adding mixed organic acids, the Cu and Zn sorption capacity in soils was decreased markedly compared with enhanced Pb and Cd sorption capacity in soils. The sorption was analyzed using Langmuir and Freundlich equations with R 2 values that ranged from 0.956 to 0.999 and 0.919 to 0.997, respectively.

  13. Organic acids, amino acids compositions in the root exudates and Cu-accumulation in castor (Ricinus communis L.) Under Cu stress.

    Science.gov (United States)

    Huang, Guoyong; Guo, Guangguang; Yao, Shiyuan; Zhang, Na; Hu, Hongqing

    2016-01-01

    Ricinus communis L. is a hyperaccumulation plant newly discovered in an abandoned land of Cu mine in China. A hydroponic experiment was then carried out to determine the root exudates in the Cu-tolerant castor (Ricinus communis L.). Plants were grown in nutrient solution with increasing level of Cu doses (0, 100, 250, 500, and 750 μmol/L Cu) in the form of CuSO4. Cu accumulation in the roots and shoots of castor, and root exudates collected from the castor were measured. The results indicated that the castor had a high Cu accumulation capacity and the Cu concentrations in the shoots and roots of the castor treated with 750 μmol/L Cu were 177.1, 14586.7 mg/kg, respectively. Tartaric was the largest in the root exudates in terms of concentrations, which reached up to 329.13 μmol/g (dry plant) in the level of 750 μmol/L Cu. There was a significantly positive linear relationship between the Cu concentration in root and the concentration of succinic (R = 0.92, P < 0.05), tartaric (R = 0.96, P < 0.01), and citric (R = 0.89, P < 0.05). These results indicated that the difference in root exudation from castor could affect their Cu tolerance. What is more, significant is that the high tartaric and citric, the low oxalic and cysteine in the root exudation of castor contributed to toleration of high Cu concentrations.

  14. Trichoderma spp. Improve growth of Arabidopsis seedlings under salt stress through enhanced root development, osmolite production, and Na⁺ elimination through root exudates.

    Science.gov (United States)

    Contreras-Cornejo, Hexon Angel; Macías-Rodríguez, Lourdes; Alfaro-Cuevas, Ruth; López-Bucio, José

    2014-06-01

    Salt stress is an important constraint to world agriculture. Here, we report on the potential of Trichoderma virens and T. atroviride to induce tolerance to salt in Arabidopsis seedlings. We first characterized the effect of several salt concentrations on shoot biomass production and root architecture of Arabidopsis seedlings. We found that salt repressed plant growth and root development in a dose-dependent manner by blocking auxin signaling. Analysis of the wild type and eir1, aux1-7, arf7arf19, and tir1abf2abf19 auxin-related mutants revealed a key role for indole-3-acetic acid (IAA) signaling in mediating salt tolerance. We also found that T. virens (Tv29.8) and T. atroviride (IMI 206040) promoted plant growth in both normal and saline conditions, which was related to the induction of lateral roots and root hairs through auxin signaling. Arabidopsis seedlings grown under saline conditions inoculated with Trichoderma spp. showed increased levels of abscissic acid, L-proline, and ascorbic acid, and enhanced elimination of Na⁺ through root exudates. Our data show the critical role of auxin signaling and root architecture to salt tolerance in Arabidopsis and suggest that these fungi may enhance the plant IAA level as well as the antioxidant and osmoprotective status of plants under salt stress.

  15. Chromium toxicity tolerance of Solanum nigrum L. and Parthenium hysterophorus L. plants with reference to ion pattern, antioxidation activity and root exudation.

    Science.gov (United States)

    UdDin, Islam; Bano, Asghari; Masood, Sajid

    2015-03-01

    Chromium (Cr), being a highly toxic metal, adversely affects the mineral uptake and metabolic processes in plants when present in excess. The current study was aimed at investigating the Cr accumulation in various plant tissues and its relation to the antioxidation activity and root exudation. Plants were grown in soil spiked with different concentrations of Cr for three weeks in pots and analysed for different growth, antioxidants and ion attributes. Furthermore, plants treated with different concentrations of Cr in pots were shifted to rhizobox-like system for 48h and organic acids were monitored in the mucilage dissolved from the plant root surface, mirroring rhizospheric solution. The results revealed that the Cr application at 1mM increased the shoot fresh and dry weight and root dry weight of Solanum nigrum, whereas the opposite was observed for Parthenium hysterophorus when compared with lower levels of Cr (0.5mM) or control treatment. In both plant species, Cr and Cl concentrations were increased while Ca, Mg and K concentrations in root, shoot and root exudates were decreased with increasing levels of Cr. Higher levels of Cr treatments enhanced the activities of SOD, POD and proline content in leaves of S. nigrum, whereas lower levels of Cr treatment were found to have stimulatory effects in P. hysterophorus. P. hysterophorus exhibited highest exudation of organic acid contents. With increasing levels of Cr treatments, citric acid concentration in root exudates increased by 35% and 44% in S. nigrum, whereas 20% and 76% in P. hysterophorus. Cr toxicity was responsible for the shoot growth reduction of S. nigrum and P. hysterophorus, however, shoot growth response was different at different levels of applied Cr. Consequently, Cr stress negatively altered the plant physiology and biochemistry. However, the enhanced antioxidant production, Cl uptake and root exudation are the physiological and biochemical indicators for the plant adaptations in biotic systems

  16. Polyphenols, including the new Peapolyphenols A-C, from pea root exudates stimulate Orobanche foetida seed germination.

    Science.gov (United States)

    Evidente, Antonio; Cimmino, Alessio; Fernández-Aparicio, Monica; Andolfi, Anna; Rubiales, Diego; Motta, Andrea

    2010-03-10

    Three new polyphenols, named peapolyphenols A-C, together with an already well-known polyphenol and a chalcone (1-(2,4-dihydroxyphenyl)-3-hydroxy-3-(4-hydroxyphenyl)-1-propanone and 1-(2,4-dihydroxyphenyl)-3-(4-methoxyphenyl)propenone) were isolated from pea root exudates. They were found to strongly stimulate Orobanche and Phelipanche species seed germination. Interestingly, only peapolyphenol A, 1,3,3-substituted propanone, and 1,3-disubstituted propenone had specific stimulatory activity on O. foetida, excluding any other Orobanche or Phelipanche species tested. This species specificity is relevant, as O. foetida does not respond to the synthetic strigolactone analogue GR24, commonly used as a standard for germination assays. As characterized by spectroscopic methods, peapolyphenols A-C proved to be differently functionalized polyphenols with hydroxy and methoxy groups on both the aromatic rings and the propyl chain.

  17. Root biomass and exudates link plant diversity with soil bacterial and fungal biomass

    NARCIS (Netherlands)

    Eisenhauer, Nico; Lanoue, Arnaud; Strecker, Tanja; Scheu, Stefan; Steinauer, Katja; Thakur, Madhav P.; Mommer, Liesje

    2017-01-01

    Plant diversity has been shown to determine the composition and functioning of soil biota. Although root-derived organic inputs are discussed as the main drivers of soil communities, experimental evidence is scarce. While there is some evidence that higher root biomass at high plant diversity

  18. Data from: Root biomass and exudates link plant diversity with soil bacterial and fungal biomass

    NARCIS (Netherlands)

    Eisenhauer, Nico; Strecker, Tanja; Lanoue, Arnaud; Scheu, Stefan; Steinauer, Katja; Thakur, Madhav P.; Mommer, L.

    2017-01-01

    Plant diversity has been shown to determine the composition and functioning of soil biota. Although root-derived organic inputs are discussed as the main drivers of soil communities, experimental evidence is scarce. While there is some evidence that higher root biomass at high plant diversity

  19. Cadmium spiked soil modulates root organic acids exudation and ionic contents of two differentially Cd tolerant maize (Zea mays L.) cultivars.

    Science.gov (United States)

    Javed, M Tariq; Akram, M Sohail; Tanwir, Kashif; Javed Chaudhary, Hassan; Ali, Qasim; Stoltz, Eva; Lindberg, Sylvia

    2017-07-01

    Our earlier work described that the roots of two maize cultivars, grown hydroponically, differentially responded to cadmium (Cd) stress by initiating changes in medium pH depending on their Cd tolerance. The current study investigated the root exudation, elemental contents and antioxidant behavior of the same maize cultivars [cv. 3062 (Cd-tolerant) and cv. 31P41 (Cd-sensitive)] under Cd stress. Plants were maintained in a rhizobox-like system carrying soil spiked with Cd concentrations of 0, 10, 20, 30, 40 and 50 μmol/kg soil. The root and shoot Cd contents increased, while Mg, Ca and Fe contents mainly decreased at higher Cd levels, and preferentially in the sensitive cultivar. Interestingly, the K contents increased in roots of cv. 3062 at low Cd treatments. The Cd stress caused acidosis of the maize root exudates predominantly in cv. 3062. The concentration of various organic acids was significantly increased in the root exudates of cv. 3062 with applied Cd levels. This effect was diminished in cv. 31P41 at higher Cd levels. Cd exposure increased the relative membrane permeability, anthocyanin (only in cv. 3062), proline contents and the activities of peroxidases (POD) and superoxide dismutase (SOD). The only exception was the catalase activity, which was diminished in both cultivars. Root Cd contents were positively correlated with the secretion of acetic acid, oxalic acid, glutamic acid, citric acid, and succinic acid. The antioxidants like POD and SOD exhibited a positive correlation with the organic acids under Cd stress. It is likly that a high exudation of dicarboxylic organic acids improves nutrient uptake and activities of antioxidants, which enables the tolerant cultivar to acclimatize in Cd polluted environment. Copyright © 2017 Elsevier Inc. All rights reserved.

  20. Response-based selection of barley cultivars and legume species for complementarity: Root morphology and exudation in relation to nutrient source.

    Science.gov (United States)

    Giles, Courtney D; Brown, Lawrie K; Adu, Michael O; Mezeli, Malika M; Sandral, Graeme A; Simpson, Richard J; Wendler, Renate; Shand, Charles A; Menezes-Blackburn, Daniel; Darch, Tegan; Stutter, Marc I; Lumsdon, David G; Zhang, Hao; Blackwell, Martin S A; Wearing, Catherine; Cooper, Patricia; Haygarth, Philip M; George, Timothy S

    2017-02-01

    Phosphorus (P) and nitrogen (N) use efficiency may be improved through increased biodiversity in agroecosystems. Phenotypic variation in plants' response to nutrient deficiency may influence positive complementarity in intercropping systems. A multicomponent screening approach was used to assess the influence of P supply and N source on the phenotypic plasticity of nutrient foraging traits in barley (H. vulgare L.) and legume species. Root morphology and exudation were determined in six plant nutrient treatments. A clear divergence in the response of barley and legumes to the nutrient treatments was observed. Root morphology varied most among legumes, whereas exudate citrate and phytase activity were most variable in barley. Changes in root morphology were minimized in plants provided with ammonium in comparison to nitrate but increased under P deficiency. Exudate phytase activity and pH varied with legume species, whereas citrate efflux, specific root length, and root diameter lengths were more variable among barley cultivars. Three legume species and four barley cultivars were identified as the most responsive to P deficiency and the most contrasting of the cultivars and species tested. Phenotypic response to nutrient availability may be a promising approach for the selection of plant combinations for minimal input cropping systems. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  1. Tobacco Rotated with Rapeseed for Soil-Borne Phytophthora Pathogen Biocontrol: Mediated by Rapeseed Root Exudates

    Directory of Open Access Journals (Sweden)

    Yuting Fang

    2016-06-01

    Full Text Available Black shank, caused by Phytophthora parasitica var. nicotianae, is a widespread and destructive disease of tobacco. Crop rotation is essential in controlling black shank. Here, we confirmed that rotating black shank-infested fields with rapeseed (Brassica napus suppressed the incidence this disease. Further study demonstrated that rapeseed roots have a strong ability to attract zoospores and subsequently stop the swimming of zoospores into cystospores. Then, rapeseed roots secrete a series of antimicrobial compounds, including 2-butenoic acid, benzothiazole, 2-(methylthiobenzothiazole, 1-(4-ethylphenyl-ethanone, and 4-methoxyindole, to inhibit the cystospore germination and mycelial growth of P. parasitica var. nicotianae. Thus, rapeseed rotated with tobacco suppresses tobacco black shank disease through the chemical weapons secreted by rapeseed roots.

  2. Influence of root exudates and soil on attachment of Pasteuria penetrans to root-knot nematode Meloidogyne arenaria

    Science.gov (United States)

    Pasteuria penetrans is a parasite of root-knot nematode (Meloidogyne spp.). Spores of P. penetrans attach to the cuticle of second stage juvenile (J2) and sterilize infected female. This study looked at different factors that influence spore attachment of P. penetrans to M. arenaria. Incubating J2 ...

  3. Organic compounds in root exudates of Miscanthus × Giganteus greef et deu and limitation of microorganisms in its rhizosphere by nutrients

    Directory of Open Access Journals (Sweden)

    Hana Kaňová

    2010-01-01

    Full Text Available This study was conducted to determine the composition of sugars and organic acids in root exudates of Miscanthus × Giganteus and to find out if microorganisms of the rhizospheric soil are limited by mi­ne­ral nutrients. The following sugars and organic acids were determined in root exudates of this plant: glucose, saccharose, and acids such as succinic, propionic, citric, tartaric, malic, oxalic, ascorbic, acetic and fumaric. Respiration of soil from rhizosphere of Miscanthus × Giganteus was found to be limited by N, K and Ca. Respiration rate after application of mineral compounds increased in following orther: nitrate > calcium > potassium > ammonium, giving approx. 165, 99, 52 and 31 % increase compared to control. Further research is necessary to determine the role of plant nutrients from the point of their limitations for rhizosphere microorganisms, to broader very rare knowledges in this topic, especially for polluted soils to stimulate efficiency of phytoremediations.

  4. Effect of root exudates of various plants on composition of bacteria and fungi communities with special regard to pathogenic soil-borne fungi

    OpenAIRE

    Danuta Piętka; Elżbieta Patkowska

    2013-01-01

    The purpose of the studies conducted in the years 1996 - 1998 was to determine the composition of bacteria and fungi populations in the rhizosphere of winter wheat, spring wheat, soybean and potato, and in non-rhizosphere soil. Besides, the effect of root exudates of these plants on the formation of pathogenic fungi communities was established. The microbiological analysis showed that the greatest tolal number of bacteria was found in the rhizospheres of potato and soybean, and the lowest num...

  5. Bioavailable concentrations of germanium and rare earth elements in soil as affected by low molecular weight organic acids and root exudates

    Science.gov (United States)

    Wiche, Oliver; Székely, Balázs; Kummer, Nicolai-Alexeji; Heinemann, Ute; Tesch, Silke; Heilmeier, Hermann

    2014-05-01

    Availability of elements in soil to plant is generally dependent on the solubility and mobility of elements in soil solution which is controlled by soil, elemental properties and plant-soil interactions. Low molecular organic acids or other root exudates may increase mobility and availability of certain elements for plants as an effect of lowering pH in the rhizosphere and complexation. However, these processes take place in a larger volume in soil, therefore to understand their nature, it is also important to know in which layers of the soil what factors modify these processes. In this work the influence of citric acid and root exudates of white lupin (Lupinus albus L.) on bioavailable concentrations of germanium, lanthan, neodymium, gadolinium and erbium in soil solution and uptake in root and shoot of rape (Brassica napus L.), comfrey (Symphytum officinale L.), common millet (Panicum milliaceum L.) and oat (Avena sativa L.) was investigated. Two different pot experiments were conducted: (1) the mentioned plant species were treated with nutrient solutions containing various amount of citric acid; (2) white lupin was cultivated in mixed culture (0 % lupin, 33 % lupin) with oat (Avena sativa L.) and soil solution was obtained by plastic suction cups placed at various depths. As a result, addition of citric acid significantly increased germanium concentrations in plant tissue of comfrey and rape and increased translocation of germanium, lanthan, neodymium, gadolinium and erbium from root to shoot. The cultivation of white lupin in mixed culture with oat led to significantly higher concentrations of germanium and increasing concentrations of lanthan, neodymium, gadolinium and erbium in soil solution and aboveground plant tissue. In these pots concentrations of citric acid in soil solution were significantly higher than in the control. The results show, that low molecular organic acids exuded by plant roots are of great importance for the mobilization of germanium

  6. Antinematicidal Efficacy Of Root Exudates Of Some Crotalaria Species On Meloidogyne Incognita Root-Knot Nematode Kofoid And White Chitwood Isolated From Infected Lycopersicum Esculentum L.Tomato Plant

    Directory of Open Access Journals (Sweden)

    L.S Danahap

    2015-08-01

    Full Text Available The antinematicidal efficacies of exudates of four common weeds Crotalaria breviflora Crotalaria juncea Crotalaria retusa and Crotalaria spectabilis were carried out against Meloidogyne incognita. The young actively growing seedling of the common weeds were uprooted and taken to the laboratory for analyses. The root exudates of test plants were prepared by growing the young actively growing seedlings in test tubes wrapped with black carbon paper for five days under lighted florescent bulbs. Root exudates of Crotalaria breviflora Crotalaria juncea Crotalaria retusa and Crotalaria spectabilis exhibited nematicidal properties against the Meloidogyne incognita. The effects varied with concentrations of the exudates P0.05 using analysis of variance ANOVA. The effects also differed among test plants with Crotalaria retusa topping in terms of reduction in nematode population. This was followed by C.breviflora C.juncea and C.spectabilis respectively. The results thus confirmed that all the test plants are potentially viable trap weeds and can be used for the control of Meloidogyne incognita and should be employed as such.

  7. Interaction of Pseudostellaria heterophylla with Fusarium oxysporum f.sp. heterophylla mediated by its root exudates in a consecutive monoculture system.

    Science.gov (United States)

    Zhao, Yongpo; Wu, Linkun; Chu, Leixia; Yang, Yanqiu; Li, Zhenfang; Azeem, Saadia; Zhang, Zhixing; Fang, Changxun; Lin, Wenxiong

    2015-02-03

    In this study, quantitative real-time PCR (qPCR) was used to determine the amount of Fusarium oxysporum, an important replant disease pathogen in Pseudostellaria heterophylla rhizospheric soil. Moreover, HPLC was used to identify phenolic acids in root exudates then it was further to explore the effects of the phenolic acid allelochemicals on the growth of F. oxysporum f.sp. heterophylla. The amount of F. oxysporum increased significantly in P. heterophylla rhizosphere soil under a consecutive replant system as monitored through qPCR analysis. Furthermore, the growth of F. oxysporum f.sp. heterophylla mycelium was enhanced by root exudates with a maximum increase of 23.8%. In addition, the number of spores increased to a maximum of 12.5-fold. Some phenolic acids promoted the growth of F. oxysporum f.sp. heterophylla mycelium and spore production. Our study revealed that phenolic acids in the root secretion of P. heterophylla increased long with its development, which was closely related to changes in rhizospheric microorganisms. The population of pathogenic microorganisms such as F. oxysporum in the rhizosphere soil of P. heterophylla also sharply increased. Our results on plant-microbe communication will help to better clarify the cause of problems associated with P. heterophylla under consecutive monoculture treatment.

  8. Comparative Transcriptomics of Bacillus mycoides Strains in Response to Potato-Root Exudates Reveals Different Genetic Adaptation of Endophytic and Soil Isolates.

    Science.gov (United States)

    Yi, Yanglei; de Jong, Anne; Frenzel, Elrike; Kuipers, Oscar P

    2017-01-01

    Plant root secreted compounds alter the gene expression of associated microorganisms by acting as signal molecules that either stimulate or repel the interaction with beneficial or harmful species, respectively. However, it is still unclear whether two distinct groups of beneficial bacteria, non-plant-associated (soil) strains and plant-associated (endophytic) strains, respond uniformly or variably to the exposure with root exudates. Therefore, Bacillus mycoides , a potential biocontrol agent and plant growth-promoting bacterium, was isolated from the endosphere of potatoes and from soil of the same geographical region. Confocal fluorescence microscopy of plants inoculated with GFP-tagged B. mycoides strains showed that the endosphere isolate EC18 had a stronger plant colonization ability and competed more successfully for the colonization sites than the soil isolate SB8. To dissect these phenotypic differences, the genomes of the two strains were sequenced and the transcriptome response to potato root exudates was compared. The global transcriptome profiles evidenced that the endophytic isolate responded more pronounced than the soil-derived isolate and a higher number of significant differentially expressed genes were detected. Both isolates responded with the alteration of expression of an overlapping set of genes, which had previously been reported to be involved in plant-microbe interactions; including organic substance metabolism, oxidative reduction, and transmembrane transport. Notably, several genes were specifically upregulated in the endosphere isolate EC18, while being oppositely downregulated in the soil isolate SB8. These genes mainly encoded membrane proteins, transcriptional regulators or were involved in amino acid metabolism and biosynthesis. By contrast, several genes upregulated in the soil isolate SB8 and downregulated in the endosphere isolate EC18 were related to sugar transport, which might coincide with the different nutrient availability

  9. Systems approaches to study root architecture dynamics

    Directory of Open Access Journals (Sweden)

    Candela eCuesta

    2013-12-01

    Full Text Available The plant root system is essential for providing anchorage to the soil, supplying minerals and water, and synthesizing metabolites. It is a dynamic organ modulated by external cues such as environmental signals, water and nutrients availability, salinity and others. Lateral roots are initiated from the primary root post-embryonically, after which they progress through discrete developmental stages which can be independently controlled, providing a high level of plasticity during root system formation.Within this review, main contributions are presented, from the classical forward genetic screens to the more recent high-throughput approaches, combined with computer model predictions, dissecting how lateral roots and thereby root system architecture is established and developed.

  10. Methane and Root Dynamics in Arctic Soil

    DEFF Research Database (Denmark)

    D'Imperio, Ludovica

    on the global climate. We investigated two aspects of arctic ecosystem dynamics which are not well represented in climatic models: i) soil methane (CH4) oxidation in dry heath tundra and barren soils and ii) root dynamics in wetlands. Field measurements were carried out during the growing season in Disko Island...

  11. Effects of P limitation and molecules from peanut root exudates on pqqE gene expression and pqq promoter activity in the phosphate-solubilizing strain Serratia sp. S119.

    Science.gov (United States)

    Ludueña, Liliana M; Anzuay, Maria S; Magallanes-Noguera, Cynthia; Tonelli, Maria L; Ibañez, Fernando J; Angelini, Jorge G; Fabra, Adriana; McIntosh, Matthew; Taurian, Tania

    2017-10-01

    The mineral phosphate-solubilizing phenotype in bacteria is attributed predominantly to secretion of gluconic acid produced by oxidation of glucose by the glucose dehydrogenase enzyme and its cofactor, pyrroloquinoline quinone. This study analyzes pqqE gene expression and pqq promoter activity in the native phosphate-solubilizing bacterium Serratia sp S119 growing under P-limitation, and in the presence of root exudates obtained from peanut plants, also growing under P-limitation. Results indicated that Serratia sp. S119 contains a pqq operon composed of six genes (pqqA,B,C,D,E,F) and two promoters, one upstream of pqqA and other between pqqA and pqqB. PqqE gene expression and pqq promoter activity increased under P-limiting growth conditions and not under N-deficient conditions. In the plant-bacteria interaction assay, the activity of the bacterial pqq promoter region varied depending on the concentration and type of root exudates and on the bacterial growth phase. Root exudates from peanut plants growing under P-available and P-limiting conditions showed differences in their composition. It is concluded from this study that the response of Serratia sp. S119 to phosphorus limitation involves an increase in expression of pqq genes, and that molecules exuded by peanut roots modify expression of these phosphate-solubilizing bacterial genes during plant-bacteria interactions. Copyright © 2017 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

  12. Plasma membrane H+-ATPase-dependent citrate exudation from cluster roots of phosphate-deficient white lupin

    DEFF Research Database (Denmark)

    Tomasi, Nicola; Kretzschmar, Tobias; Espen, Luca

    2009-01-01

    ABSTRACT White lupin (Lupinus albus L.) is able to grow on soils with sparingly available phosphate (P) by producing specialized structures called cluster roots.To mobilize sparingly soluble P forms in soils, cluster roots release substantial amounts of carboxylates and concomitantly acidify the ...

  13. Quantification and role of organic acids in cucumber root exudates in Trichoderma harzianum T-E5 colonization.

    Science.gov (United States)

    Zhang, Fengge; Meng, Xiaohui; Yang, Xingming; Ran, Wei; Shen, Qirong

    2014-10-01

    The ability to colonize on plant roots is recognized as one of the most important characteristics of the beneficial fungi Trichoderma spp. The aim of this study is to prove that the utilization of organic acids is a major trait of Trichoderma harzianum T-E5 for colonization of cucumber roots. A series experiments in split-root hydroponic system and in vitro were designed to demonstrate the association between the utilization of organic acids and T-E5 colonization on cucumber roots. In the split-root hydroponic system, inoculation with T-E5 (T) significantly increased the biomass of cucumber plants compared with CK (non-inoculation with T-E5). The T-E5 hyphae densely covering the cucumber root surface were observed by scanning electron microscopy (SEM). Three organic acids (oxalic acid, malic acid and citric acid) were identified from both the CK and T treatments by HPLC and LC/ESI-MS procedures. The amounts of oxalic acid and malic acid in T were significantly higher than those in CK. All the organic acids exhibited different and significant stimulation effects on the mycelial growth and conidial germination of T-E5 in vitro. An additional hydroponic experiment demonstrated the positive effects of organic acids on the T-E5 colonization of cucumber roots. In conclusion, the present study revealed that certain organic acids could be used as nutritional sources for Trichoderma harzianum T-E5 to reinforce its population on cucumber roots. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

  14. Volatile compounds from beneficial or pathogenic bacteria differentially regulate root exudation, transcription of iron transporters, and defense signaling pathways in Sorghum bicolor.

    Science.gov (United States)

    Hernández-Calderón, Erasto; Aviles-Garcia, Maria Elizabeth; Castulo-Rubio, Diana Yazmín; Macías-Rodríguez, Lourdes; Ramírez, Vicente Montejano; Santoyo, Gustavo; López-Bucio, José; Valencia-Cantero, Eduardo

    2018-02-01

    Our results show that Sorghum bicolor is able to recognize bacteria through its volatile compounds and differentially respond to beneficial or pathogens via eliciting nutritional or defense adaptive traits. Plants establish beneficial, harmful, or neutral relationships with bacteria. Plant growth promoting rhizobacteria (PGPR) emit volatile compounds (VCs), which may act as molecular cues influencing plant development, nutrition, and/or defense. In this study, we compared the effects of VCs produced by bacteria with different lifestyles, including Arthrobacter agilis UMCV2, Bacillus methylotrophicus M4-96, Sinorhizobium meliloti 1021, the plant pathogen Pseudomonas aeruginosa PAO1, and the commensal rhizobacterium Bacillus sp. L2-64, on S. bicolor. We show that VCs from all tested bacteria, except Bacillus sp. L2-64, increased biomass and chlorophyll content, and improved root architecture, but notheworthy A. agilis induced the release of attractant molecules, whereas P. aeruginosa activated the exudation of growth inhibitory compounds by roots. An analysis of the expression of iron-transporters SbIRT1, SbIRT2, SbYS1, and SbYS2 and genes related to plant defense pathways COI1 and PR-1 indicated that beneficial, pathogenic, and commensal bacteria could up-regulate iron transporters, whereas only beneficial and pathogenic species could induce a defense response. These results show how S. bicolor could recognize bacteria through their volatiles profiles and highlight that PGPR or pathogens can elicit nutritional or defensive traits in plants.

  15. SOIL RESPIRED D13C SIGNATURES REFLECT ROOT EXUDATE OR ROOT TURNOVER SIGNATURES IN AN ELEVATED CO2 AND OZONE MESOCOSM EXPERIMENT

    Science.gov (United States)

    Bulk tissue and root and soil respired d13C signatures were measured throughout the soil profile in a Ponderosa Pine mesocosm experiment exposed to ambient and elevated CO2 concentrations. For the ambient treatment, root (0-1mm, 1-2mm, and >2mm) and soil d13C signatures were ?24...

  16. Differential effects of fine root morphology on water dynamics in the root-soil interface

    Science.gov (United States)

    DeCarlo, K. F.; Bilheux, H.; Warren, J.

    2017-12-01

    Soil water uptake form plants, particularly in the rhizosphere, is a poorly understood question in the plant and soil sciences. Our study analyzed the role of belowground plant morphology on soil structural and water dynamics of 5 different plant species (juniper, grape, maize, poplar, maple), grown in sandy soils. Of these, the poplar system was extended to capture drying dynamics. Neutron radiography was used to characterize in-situ dynamics of the soil-water-plant system. A joint map of root morphology and soil moisture was created for the plant systems using digital image processing, where soil pixels were connected to associated root structures via minimum distance transforms. Results show interspecies emergent behavior - a sigmoidal relationship was observed between root diameter and bulk/rhizosphere soil water content difference. Extending this as a proxy for extent of rhizosphere development with root age, we observed a logistic growth pattern for the rhizosphere: minimal development in the early stages is superceded by rapid onset of rhizosphere formation, which then stabilizes/decays with the likely root suberization. Dynamics analysis of water content differences between the root/rhizosphere, and rhizosphere/bulk soil interface highlight the persistently higher water content in the root at all water content and root size ranges. At the rhizosphere/bulk soil interface, we observe a shift in soil water dynamics by root size: in super fine roots, we observe that water content is primarily lower in the rhizosphere under wetter conditions, which then gradually increases to a relatively higher water content under drier conditions. This shifts to a persistently higher rhizosphere water content relative to bulk soil in both wet/dry conditions with increased root size, suggesting that, by size, the finest root structures may contribute the most to total soil water uptake in plants.

  17. Allelopathic effect of black mustard tissues and root exudates on some crops and weeds Efeito alelopático de tecidos de mostarda-preta e exsudatos da raiz de algumas culturas e plantas daninhas

    Directory of Open Access Journals (Sweden)

    E Al-Sherif

    2013-03-01

    Full Text Available Laboratory and greenhouse experiments were conducted to evaluate the phytotoxic effect of black mustard extracts and root exudates on two crops: Trifolium alexandrinum and Triticum aestivum, and two weeds: Phalaris paradoxa and Sisymbrium irio. The seeds were treated with aqueous and ethanolic extracts and chloroform for eight days, or subjected to root exudates of just harvested mustard in a greenhouse for five weeks. High-performance liquid chromatography (HPLC was used to quantify phytotoxins from plant tissues. Seed germination of P. paradoxa was reduced with the lowest concentration of the different extracts. However, the aqueous extract at 4% completely curtailed the germination of all the target species. In general, plant extracts had a concentration-dependent reduction of seedling growth of the target species. However, the ethanolic extract, at the lowest concentration, has stimulated the shoot length of both T. alexandrinum and T. aestivum, and the root length of the former. Mustard root exudates inhibited emergence and growth of the target species throughout the experiment. Ferulic and syringic acids were the dominant allelochemicals found when HPLC was used.Experimentos de laboratório e estufa foram realizados para avaliar o efeito fitotóxico dos extratos de mostarda-preta e exsudatos de raiz de duas culturas: Trifolium alexandrinum e Triticum aestivum, bem como de duas plantas daninhas: Phalaris paradoxa e Sisymbrium irio. As sementes foram tratadas com extratos aquosos, etanólicos e clorofórmio por oito dias, ou submetidas a exsudatos de raiz de mostarda recém-colhidaem estufa durante cinco semanas. A cromatografia líquida de alto desempenho (HPLC foi usada para a quantificação de fitotoxinas a partir de tecidos de plantas. Sementes de P. paradoxa apresentam germinação reduzida com a menor concentração dos diferentes extratos. No entanto, o extrato aquoso a 4% restringiu completamente a germinação de todas as esp

  18. The origin and composition of cucurbit "phloem" exudate.

    Science.gov (United States)

    Zhang, Cankui; Yu, Xiyan; Ayre, Brian G; Turgeon, Robert

    2012-04-01

    Cucurbits exude profusely when stems or petioles are cut. We conducted studies on pumpkin (Cucurbita maxima) and cucumber (Cucumis sativus) to determine the origin and composition of the exudate. Morphometric analysis indicated that the exudate is too voluminous to derive exclusively from the phloem. Cold, which inhibits phloem transport, did not interfere with exudation. However, ice water applied to the roots, which reduces root pressure, rapidly diminished exudation rate. Sap was seen by microscopic examination to flow primarily from the fascicular phloem in cucumber, and several other cucurbit species, but primarily from the extrafascicular phloem in pumpkin. Following exposure of leaves to 14CO2, radiolabeled stachyose and other sugars were detected in the exudate in proportions expected of authentic phloem sap. Most of this radiolabel was released during the first 20 s. Sugars in exudate were dilute. The sugar composition of exudate from extrafascicular phloem near the edge of the stem differed from that of other sources in that it was high in hexose and low in stachyose. We conclude that sap is released from cucurbit phloem upon wounding but contributes negligibly to total exudate volume. The sap is diluted by water from cut cells, the apoplast, and the xylem. Small amounts of dilute, mobile sap from sieve elements can be obtained, although there is evidence that it is contaminated by the contents of other cell types. The function of P-proteins may be to prevent water loss from the xylem as well as nutrient loss from the phloem.

  19. Transcriptomic profiling of Burkholderia phymatum STM815, Cupriavidus taiwanensis LMG19424 and Rhizobium mesoamericanum STM3625 in response to Mimosa pudica root exudates illuminates the molecular basis of their nodulation competitiveness and symbiotic evolutionary history.

    Science.gov (United States)

    Klonowska, Agnieszka; Melkonian, Rémy; Miché, Lucie; Tisseyre, Pierre; Moulin, Lionel

    2018-01-30

    Rhizobial symbionts belong to the classes Alphaproteobacteria and Betaproteobacteria (called "alpha" and "beta"-rhizobia). Most knowledge on the genetic basis of symbiosis is based on model strains belonging to alpha-rhizobia. Mimosa pudica is a legume that offers an excellent opportunity to study the adaptation toward symbiotic nitrogen fixation in beta-rhizobia compared to alpha-rhizobia. In a previous study (Melkonian et al., Environ Microbiol 16:2099-111, 2014) we described the symbiotic competitiveness of M. pudica symbionts belonging to Burkholderia, Cupriavidus and Rhizobium species. In this article we present a comparative analysis of the transcriptomes (by RNAseq) of B. phymatum STM815 (BP), C. taiwanensis LMG19424 (CT) and R. mesoamericanum STM3625 (RM) in conditions mimicking the early steps of symbiosis (i.e. perception of root exudates). BP exhibited the strongest transcriptome shift both quantitatively and qualitatively, which mirrors its high competitiveness in the early steps of symbiosis and its ancient evolutionary history as a symbiont, while CT had a minimal response which correlates with its status as a younger symbiont (probably via acquisition of symbiotic genes from a Burkholderia ancestor) and RM had a typical response of Alphaproteobacterial rhizospheric bacteria. Interestingly, the upregulation of nodulation genes was the only common response among the three strains; the exception was an up-regulated gene encoding a putative fatty acid hydroxylase, which appears to be a novel symbiotic gene specific to Mimosa symbionts. The transcriptional response to root exudates was correlated to each strain nodulation competitiveness, with Burkholderia phymatum appearing as the best specialised symbiont of Mimosa pudica.

  20. Fine-root growth in a forested bog is seasonally dynamic, but shallowly distributed in nutrient-poor peat

    Science.gov (United States)

    Colleen M. Iversen; Joanne Childs; Richard J. Norby; Todd A. Ontl; Randall K. Kolka; Deanne J. Brice; Karis J. McFarlane; Paul J. Hanson

    2017-01-01

    Background and aims. Fine roots contribute to ecosystem carbon, water, and nutrient fluxes through resource acquisition, respiration, exudation, and turnover, but are understudied in peatlands. We aimed to determine how the amount and timing of fine-root growth in a forested, ombrotrophic bog varied across gradients of vegetation density, peat...

  1. Reduced ABA Accumulation in the Root System is Caused by ABA Exudation in Upland Rice (Oryza sativa L. var. Gaoshan1) and this Enhanced Drought Adaptation.

    Science.gov (United States)

    Shi, Lu; Guo, Miaomiao; Ye, Nenghui; Liu, Yinggao; Liu, Rui; Xia, Yiji; Cui, Suxia; Zhang, Jianhua

    2015-05-01

    Lowland rice (Nipponbare) and upland rice (Gaoshan 1) that are comparable under normal and moderate drought conditions showed dramatic differences in severe drought conditions, both naturally occurring long-term drought and simulated rapid water deficits. We focused on their root response and found that enhanced tolerance of upland rice to severe drought conditions was mainly due to the lower level of ABA in its roots than in those of the lowland rice. We first excluded the effect of ABA biosynthesis and catabolism on root-accumulated ABA levels in both types of rice by monitoring the expression of four OsNCED genes and two OsABA8ox genes. Next, we excluded the impact of the aerial parts on roots by suppressing leaf-biosynthesized ABA with fluridone and NDGA (nordihydroguaiaretic acid), and measuring the ABA level in detached roots. Instead, we proved that upland rice had the ability to export considerably more root-sourced ABA than lowland rice under severe drought, which improved ABA-dependent drought adaptation. The investigation of apoplastic pH in root cells and root anatomy showed that ABA leakage in the root system of upland rice was related to high apoplastic pH and the absence of Casparian bands in the sclerenchyma layer. Finally, taking some genes as examples, we predicted that different ABA levels in rice roots stimulated distinct ABA perception and signaling cascades, which influenced its response to water stress. © The Author 2015. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  2. Plant exudates promote PCB degradation by a rhodococcal rhizobacteria

    Energy Technology Data Exchange (ETDEWEB)

    Toussaint, Jean-Patrick; Pham, Thi Thanh My; Barriault, Diane; Sylvestre, Michel [Instiut National de la Recherche Scientifique INRS, Laval, QC (Canada). Inst. Armand-Frappier

    2012-09-15

    Rhodococcus erythropolis U23A is a polychlorinated biphenyl (PCB)-degrading bacterium isolated from the rhizosphere of plants grown on a PCB-contaminated soil. Strain U23A bphA exhibited 99% identity with bphA1 of Rhodococcus globerulus P6. We grew Arabidopsis thaliana in a hydroponic axenic system, collected, and concentrated the plant secondary metabolite-containing root exudates. Strain U23A exhibited a chemotactic response toward these root exudates. In a root colonizing assay, the number of cells of strain U23A associated to the plant roots (5.7 x 105 CFU g{sup -1}) was greater than the number remaining in the surrounding sand (4.5 x 104 CFU g{sup -1}). Furthermore, the exudates could support the growth of strain U23A. In a resting cell suspension assay, cells grown in a minimal medium containing Arabidopsis root exudates as sole growth substrate were able to metabolize 2,3,4'- and 2,3',4-trichlorobiphenyl. However, no significant degradation of any of congeners was observed for control cells grown on Luria-Bertani medium. Although strain U23A was unable to grow on any of the flavonoids identified in root exudates, biphenyl-induced cells metabolized flavanone, one of the major root exudate components. In addition, when used as co-substrate with sodium acetate, flavanone was as efficient as biphenyl to induce the biphenyl catabolic pathway of strain U23A. Together, these data provide supporting evidence that some rhodococci can live in soil in close association with plant roots and that root exudates can support their growth and trigger their PCB-degrading ability. This suggests that, like the flagellated Gram-negative bacteria, non-flagellated rhodococci may also play a key role in the degradation of persistent pollutants. (orig.)

  3. Use of an exchange method to estimate the association and dissociation rate constants of cadmium complexes formed with low-molecular-weight organic acids commonly exuded by plant roots.

    Science.gov (United States)

    Schneider, André; Nguyen, Christophe

    2011-01-01

    Organic acids released from plant roots can form complexes with cadmium (Cd) in the soil solution and influence metal bioavailability not only due to the nature and concentration of the complexes but also due to their lability. The lability of a complex influences its ability to buffer changes in the concentration of free ions (Cd); it depends on the association (, m mol s) and dissociation (, s) rate constants. A resin exchange method was used to estimate and (m mol s), which is the conditional estimate of depending on the calcium (Ca) concentration in solution. The constants were estimated for oxalate, citrate, and malate, three low-molecular-weight organic acids commonly exuded by plant roots and expected to strongly influence Cd uptake by plants. For all three organic acids, the and estimates were around 2.5 10 m mol s and 1.3 × 10 s, respectively. Based on the literature, these values indicate that the Cd- low-molecular-weight organic acids complexes formed between Cd and low-molecular-weight organic acids may be less labile than complexes formed with soil soluble organic matter but more labile than those formed with aminopolycarboxylic chelates. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  4. Applicability of optical scanner method for fine root dynamics

    Science.gov (United States)

    Kume, Tomonori; Ohashi, Mizue; Makita, Naoki; Khoon Kho, Lip; Katayama, Ayumi; Matsumoto, Kazuho; Ikeno, Hidetoshi

    2016-04-01

    Fine root dynamics is one of the important components in forest carbon cycling, as ~60 % of tree photosynthetic production can be allocated to root growth and metabolic activities. Various techniques have been developed for monitoring fine root biomass, production, mortality in order to understand carbon pools and fluxes resulting from fine roots dynamics. The minirhizotron method is now a widely used technique, in which a transparent tube is inserted into the soil and researchers count an increase and decrease of roots along the tube using images taken by a minirhizotron camera or minirhizotron video camera inside the tube. This method allows us to observe root behavior directly without destruction, but has several weaknesses; e.g., the difficulty of scaling up the results to stand level because of the small observation windows. Also, most of the image analysis are performed manually, which may yield insufficient quantitative and objective data. Recently, scanner method has been proposed, which can produce much bigger-size images (A4-size) with lower cost than those of the minirhizotron methods. However, laborious and time-consuming image analysis still limits the applicability of this method. In this study, therefore, we aimed to develop a new protocol for scanner image analysis to extract root behavior in soil. We evaluated applicability of this method in two ways; 1) the impact of different observers including root-study professionals, semi- and non-professionals on the detected results of root dynamics such as abundance, growth, and decomposition, and 2) the impact of window size on the results using a random sampling basis exercise. We applied our new protocol to analyze temporal changes of root behavior from sequential scanner images derived from a Bornean tropical forests. The results detected by the six observers showed considerable concordance in temporal changes in the abundance and the growth of fine roots but less in the decomposition. We also examined

  5. Non-destructive digital imaging in poplar allows detailed analysis of adventitious rooting dynamics

    Science.gov (United States)

    R.J. Kodrzycki; R.B. Michaels; A.L. Friend; R.S. Zalesny; Ch.P. Mawata; D.W. McDonald

    2008-01-01

    The dynamics of root formation are difficult to observe directly over time without disturbing the rooting environment. A novel system for a non-destructive, non-invasive root analysis (RootViz FS, Phenotype Screening Corp.) was evaluated for its ability to analyze root formation from cuttings over a 32 day period in three poplar genotypes (DN70, P. Deltoides x...

  6. [Erespal effectiveness in exudative otitis media].

    Science.gov (United States)

    Levina, Iu V; Luchikhin, L A; Krasiuk, A A

    2003-01-01

    Standard conservative treatment of exudative otitis media (EOM) was performed in 82 patients, but 44 of them received adjuvant fenspiride (erespal) in a dose 80 mg per os 3 times a day for 10 days. Dynamic pure tone audiometry, tympanometry and subjective response demonstrated higher treatment efficiency in the erespal group. Therefore, it is recommended to include erespal in combined conventional therapy of EOM.

  7. Nature's amazing biopolymer: basic mechanical and hydrological properties of soil affected by plant exudates

    Science.gov (United States)

    Naveed, Muhammad; Roose, Tiina; Raffan, Annette; George, Timothy; Bengough, Glyn; Brown, Lawrie; Keyes, Sam; Daly, Keith; Hallett, Paul

    2016-04-01

    Plant exudates are known to have a very large impact on soil physical properties through changes in mechanical and hydrological processes driven by long-chain polysaccharides and surface active compounds. Whilst these impacts are well known, the basic physical properties of these exudates have only been reported in a small number of studies. We present data for exudates obtained from barley roots and chia seeds, incorporating treatments examining biological decomposition of the exudates. When these exudates were added to a sandy loam soil, contact angle and drop penetration time increased exponentially with increasing exudate concentration. These wetting properties were strongly correlated with both exudate density and zero-shear viscosity, but not with exudate surface tension. Water holding capacity and water repellency of exudate mixed soil tremendously increased with exudate concentration, however they were significantly reduced on decomposition when measured after 14 days of incubation at 16C. Mechanical stability greatly increased with increasing exudate amendment to soils, which was assessed using a rheological amplitude sweep test near saturation, at -50 cm matric potential (field capacity) using indentation test, and at air-dry condition using the Brazilian test. This reflects that exudates not only attenuate plant water stress but also impart mechanical stability to the rhizosphere. These data are highly relevant to the understanding and modelling of rhizosphere development, which is the next phase of our research.

  8. Ryecyanatines A and B and ryecarbonitrilines A and B, substituted cyanatophenol, cyanatobenzo[1,3]dioxole, and benzo[1,3]dioxolecarbonitriles from rye (Secale cereale L.) root exudates: Novel metabolites with allelopathic activity on Orobanche seed germination and radicle growth.

    Science.gov (United States)

    Cimmino, Alessio; Fernández-Aparicio, Mónica; Avolio, Fabiana; Yoneyama, Koichi; Rubiales, Diego; Evidente, Antonio

    2015-01-01

    Orobanche and Phelipanche species (the broomrapes) are root parasitic plants, some of which represent serious weed problems causing heavy yield losses on important crops. Current control relies on the use of certain agronomic practices, resistant crop varieties, and herbicides, albeit success has been marginal. Agronomic practices such as the use of allelopathic species in intercropping or cover crops, or the use of direct seedling over residues of allelopathic species incorporate the principle of allelopathy exerted by molecules exuded from roots or released by crop residues to control broomrapes. In addition, the isolation of natural substances from root exudates of plants with potential to inhibit broomrape development opens the door to the design of new herbicides based on natural and benign sources. Ryecyanatines A and B and ryecarbonitrilines A and B, the first new substituted cyanatophenol, substituted cyanatobenzo[1,3]dioxole, and the latter two new substituted benzo[1,3]dioxolecarbonitriles were isolated from rye (Secale cereale L.) root exudates. They were characterized as 4-cyanato-2-methoxyphenol, 2-cyanato-benzo[1,3]dioxole, 2-methoxybenzo[1,3]dioxole-5-carbonitrile and benzo[1,3]dioxole-2-carbonitrile by spectroscopic (essentially NMR and HRESI MS spectra) methods. These compounds were investigated for allelopathic activity on Orobanche germination and development. Ryecarbonitriline A induced germination of Orobanche cumana seeds, and this germination can be considered as suicidal because O. cumana does not parasite rye roots and cannot survive without host resources beyond germination stage. In addition, ryecyanatine A promotes a rapid cessation of O. cumana, Orobanche crenata and Orobanche minor radicle growth with the promotion of a layer of papillae at the radicle tip in O. cumana and O. crenata hampering the contact of the parasite to the host. Ryecarbonitriline B also displayed the same activity although being less active than ryecyanatine A and

  9. Fine root dynamics and trace gas fluxes in two lowland tropical forest soils.

    Science.gov (United States)

    WHENDEE L. SILVER; ANDREW W. THOMPSON; MEGAN E . MCGRODDY; RUTH K. VARNER; JADSON D. DIAS; HUDSON SILVA; CRILL PATRICK M.; MICHAEL KELLER

    2005-01-01

    Fine root dynamics have the potential to contribute significantly to ecosystem-scale biogeochemical cycling, including the production and emission of greenhouse gases. This is particularly true in tropical forests which are often characterized as having large fine root biomass and rapid rates of root production and decomposition. We examined patterns in fine root...

  10. Striga seed-germination activity of root exudates and compounds present in stems of Striga host and nonhost (trap crop) plants is reduced due to root colonization by arbuscular mycorrhizal fungi.

    NARCIS (Netherlands)

    Lendzemo, V.W.; Kuyper, T.W.; Vierheilig, H.

    2009-01-01

    Root colonization by arbuscular mycorrhizal (AM) fungi reduces stimulation of seed germination of the plant parasite Striga (Orobanchaceae). This reduction can affect not only host plants for Striga, resulting in a lower parasite incidence, but also false hosts or trap crops, which induce suicidal

  11. Familial Exudative Vitreoretinopathy.

    Science.gov (United States)

    Sızmaz, Selçuk; Yonekawa, Yoshihiro; T Trese, Michael

    2015-08-01

    Familial exudative vitreoretinopathy (FEVR) is a hereditary disease associated with visual loss, particularly in the pediatric group. Mutations in the NDP, FZD4, LRP5, and TSPAN12 genes have been shown to contribute to FEVR. FEVR has been reported to have X-linked recessive, autosomal dominant, and autosomal recessive inheritances. However, both the genotypic and phenotypic features are variable. Novel mutations contributing to the disease have been reported. The earliest and the most prominent finding of the disease is avascularity in the peripheral retina. As the disease progresses, retinal neovascularization, subretinal exudation, partial and total retinal detachment may occur, which may be associated with certain mutations. With early diagnosis and prompt management visual loss can be prevented with laser photocoagulation and anti-VEGF injections. In case of retinal detachment, pars plana vitrectomy alone or combined with scleral buckling should be considered. Identifying asymptomatic family members with various degrees of insidious findings is of certain importance. Wide-field imaging with fluorescein angiography is crucial in the management of this disease. The differential diagnosis includes other pediatric vitreoretinopathies such as Norrie disease, retinopathy of prematurity, and Coats' disease.

  12. Familial Exudative Vitreoretinopathy

    Directory of Open Access Journals (Sweden)

    Selçuk Sızmaz

    2015-08-01

    Full Text Available Familial exudative vitreoretinopathy (FEVR is a hereditary disease associated with visual loss, particularly in the pediatric group. Mutations in the NDP, FZD4, LRP5, and TSPAN12 genes have been shown to contribute to FEVR. FEVR has been reported to have X-linked recessive, autosomal dominant, and autosomal recessive inheritances. However, both the genotypic and phenotypic features are variable. Novel mutations contributing to the disease have been reported. The earliest and the most prominent finding of the disease is avascularity in the peripheral retina. As the disease progresses, retinal neovascularization, subretinal exudation, partial and total retinal detachment may occur, which may be associated with certain mutations. With early diagnosis and prompt management visual loss can be prevented with laser photocoagulation and anti-VEGF injections. In case of retinal detachment, pars plana vitrectomy alone or combined with scleral buckling should be considered. Identifying asymptomatic family members with various degrees of insidious findings is of certain importance. Wide-field imaging with fluorescein angiography is crucial in the management of this disease. The differential diagnosis includes other pediatric vitreoretinopathies such as Norrie disease, retinopathy of prematurity, and Coats’ disease. (Turk J Ophthalmol 2015; 45: 164-168

  13. The Origin and Composition of Cucurbit “Phloem” Exudate1[OA

    Science.gov (United States)

    Zhang, Cankui; Yu, Xiyan; Ayre, Brian G.; Turgeon, Robert

    2012-01-01

    Cucurbits exude profusely when stems or petioles are cut. We conducted studies on pumpkin (Cucurbita maxima) and cucumber (Cucumis sativus) to determine the origin and composition of the exudate. Morphometric analysis indicated that the exudate is too voluminous to derive exclusively from the phloem. Cold, which inhibits phloem transport, did not interfere with exudation. However, ice water applied to the roots, which reduces root pressure, rapidly diminished exudation rate. Sap was seen by microscopic examination to flow primarily from the fascicular phloem in cucumber, and several other cucurbit species, but primarily from the extrafascicular phloem in pumpkin. Following exposure of leaves to 14CO2, radiolabeled stachyose and other sugars were detected in the exudate in proportions expected of authentic phloem sap. Most of this radiolabel was released during the first 20 s. Sugars in exudate were dilute. The sugar composition of exudate from extrafascicular phloem near the edge of the stem differed from that of other sources in that it was high in hexose and low in stachyose. We conclude that sap is released from cucurbit phloem upon wounding but contributes negligibly to total exudate volume. The sap is diluted by water from cut cells, the apoplast, and the xylem. Small amounts of dilute, mobile sap from sieve elements can be obtained, although there is evidence that it is contaminated by the contents of other cell types. The function of P-proteins may be to prevent water loss from the xylem as well as nutrient loss from the phloem. PMID:22331409

  14. Exudation of Allelopathic Substances in Buckwheat (Fagopyrum esculentum Moench)

    Czech Academy of Sciences Publication Activity Database

    Kalinová, J.; Vrchotová, Naděžda; Tříska, Jan

    2007-01-01

    Roč. 55, č. 16 (2007), s. 6453-6459 ISSN 0021-8561 Institutional research plan: CEZ:AV0Z60870520 Keywords : Allelopathy * Epicatechin * Fagopyrum esculentum * palmitic acid * root exudates Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 2.532, year: 2007

  15. Root structural and functional dynamics in terrestrial biosphere models--evaluation and recommendations.

    Science.gov (United States)

    Warren, Jeffrey M; Hanson, Paul J; Iversen, Colleen M; Kumar, Jitendra; Walker, Anthony P; Wullschleger, Stan D

    2015-01-01

    There is wide breadth of root function within ecosystems that should be considered when modeling the terrestrial biosphere. Root structure and function are closely associated with control of plant water and nutrient uptake from the soil, plant carbon (C) assimilation, partitioning and release to the soils, and control of biogeochemical cycles through interactions within the rhizosphere. Root function is extremely dynamic and dependent on internal plant signals, root traits and morphology, and the physical, chemical and biotic soil environment. While plant roots have significant structural and functional plasticity to changing environmental conditions, their dynamics are noticeably absent from the land component of process-based Earth system models used to simulate global biogeochemical cycling. Their dynamic representation in large-scale models should improve model veracity. Here, we describe current root inclusion in models across scales, ranging from mechanistic processes of single roots to parameterized root processes operating at the landscape scale. With this foundation we discuss how existing and future root functional knowledge, new data compilation efforts, and novel modeling platforms can be leveraged to enhance root functionality in large-scale terrestrial biosphere models by improving parameterization within models, and introducing new components such as dynamic root distribution and root functional traits linked to resource extraction. No claim to original US Government works. New Phytologist © 2014 New Phytologist Trust.

  16. Long-Term Effects of Season of Prescribed Burn on the Fine-Root Growth, Root Carbohydrates, and Foliar Dynamics of Mature Longleaf Pine

    Science.gov (United States)

    Eric A. Kuehler; Mary Anne Sword Sayer; James D. Haywood; C. Dan Andries

    2004-01-01

    Depending on the season and intensity of fire, as well as the phenology of foliage and new root growth, fire may damage foliage, and subsequently decrease whole-crown carbon fixation and allocation to the root system. In central Louisiana the authors investigated how season of prescribed burning affects fine-root dynamics, root carbohydrate relations, and leaf area...

  17. Dynamic parallel ROOT facility clusters on the Alice Environment

    International Nuclear Information System (INIS)

    Luzzi, C; Betev, L; Carminati, F; Grigoras, C; Saiz, P; Manafov, A

    2012-01-01

    The ALICE collaboration has developed a production environment (AliEn) that implements the full set of the Grid tools enabling the full offline computational work-flow of the experiment, simulation, reconstruction and data analysis, in a distributed and heterogeneous computing environment. In addition to the analysis on the Grid, ALICE uses a set of local interactive analysis facilities installed with the Parallel ROOT Facility (PROOF). PROOF enables physicists to analyze medium-sized (order of 200-300 TB) data sets on a short time scale. The default installation of PROOF is on a static dedicated cluster, typically 200-300 cores. This well-proven approach, has its limitations, more specifically for analysis of larger datasets or when the installation of a dedicated cluster is not possible. Using a new framework called PoD (Proof on Demand), PROOF can be used directly on Grid-enabled clusters, by dynamically assigning interactive nodes on user request. The integration of Proof on Demand in the AliEn framework provides private dynamic PROOF clusters as a Grid service. This functionality is transparent to the user who will submit interactive jobs to the AliEn system.

  18. Plant root and shoot dynamics during subsurface obstacle interaction

    Science.gov (United States)

    Conn, Nathaniel; Aguilar, Jeffrey; Benfey, Philip; Goldman, Daniel

    As roots grow, they must navigate complex underground environments to anchor and retrieve water and nutrients. From gravity sensing at the root tip to pressure sensing along the tip and elongation zone, the complex mechanosensory feedback system of the root allows it to bend towards greater depths and avoid obstacles of high impedance by asymmetrically suppressing cell elongation. Here we investigate the mechanical and physiological responses of roots to rigid obstacles. We grow Maize, Zea mays, plants in quasi-2D glass containers (22cm x 17cm x 1.4cm) filled with photoelastic gel and observe that, regardless of obstacle interaction, smaller roots branch off the primary root when the upward growing shoot (which contains the first leaf) reaches an average length of 40 mm, coinciding with when the first leaf emerges. However, prior to branching, contacts with obstacles result in reduced root growth rates. The growth rate of the root relative to the shoot is sensitive to the angle of the obstacle surface, whereby the relative root growth is greatest for horizontally oriented surfaces. We posit that root growth is prioritized when horizontal obstacles are encountered to ensure anchoring and access to nutrients during later stages of development. NSF Physics of Living Systems.

  19. [Dynamics of diazotrophic bacteria number in the root zone of wheat Vrn lines isogenic by genes].

    Science.gov (United States)

    Samoĭlov, A M; Zhmurko, V V

    2012-01-01

    The number of diazotrophic bacteria and nitrogenase activity in the root zone of isogenic monogene-dominant Vrn lines were measured in the field experiments throughout their vegetation from tillering to heading. The total number of diazotrophic bacteria and nitrogenase activity in the root zone of these lines during this period were increased irrespective of their genotypes. The above indices of the winter cultivar (Vrn loci bottom recessive) were lower than those of the spring lines--Vrn-A1, Vrn-B1 and Vrn-D1. Plants of Vrn-B1 line have the lowest indices among the spring lines with the exception of some indices. This line plants flowered later than those of Vrn-A1 and Vrn-D1 lines. We hypothesized the differences between plants of these lines as to nitrogen fixation activity and the number of diazotrophic bacteria are mediately determined by Vrn loci through their effects on metabolism intensity and assimilate reflux in the form of root exudates, therefore the total number of diazotrophic bacteria and nitrogenase activity increases.

  20. [Fine root dynamics and its relationship with soil fertility in tropical rainforests of Chocó].

    Science.gov (United States)

    Quinto, Harley; Caicedo, Haylin; Thelis Perez, May; Moreno, Flavio

    2016-12-01

    The fine roots play an important role in the acquisition of water and minerals from the soil, the global carbon balance and mitigation of climate change. The dynamics (productivity and turnover) of fine roots is essential for nutrient cycling and carbon balance of forest ecosystems. The availability of soil water and nutrients has significantly determined the productivity and turnover of fine roots. It has been hypothesized that fine roots dynamics increases with the availability of soil resources in tropical forest ecosystems. To test this hypothesis in tropical rainforests of Chocó (ecosystems with the highest rainfall in the world), five one-ha permanent plots were established in the localities of Opogodó and Pacurita, where the productivity and turnover of fine roots were measured at 0-10 cm and 10-20 cm depth. The measurement of the fine root production was realized by the Ingrowth core method. The fine root turnover was measured like fine roots production divided mean annual biomass. In addition, soil fertility parameters (pH, nutrients, and texture) were measured and their association with productivity and turnover of fine roots was evaluated. It was found that the sites had nutrient-poor soils. The localities also differ in soil; Opogodó has sandy soils and flat topography, and Pacurita has clay soils, rich in aluminum and mountainous topography. In Opogodó fine root production was 6.50 ± 2.62 t/ha.yr (mean ± SD). In Pacurita, fine root production was 3.61 ± 0.88 t/ha.yr. Also in Opogodó, the fine root turnover was higher than in Pacurita (1.17 /y and 0.62 /y, respectively). Fine root turnover and production in the upper soil layers (10 cm upper soil) was considerably higher. Productivity and turnover of fine roots showed positive correlation with pH and contents of organic matter, total N, K, Mg, and sand; whereas correlations were negative with ECEC and contents of Al, silt, and clay. The percentage of sand was the parameter that best explained

  1. Interaction of xylem and phloem during exudation and wound occlusion in Cucurbita maxima.

    Science.gov (United States)

    Zimmermann, Matthias R; Hafke, Jens B; van Bel, Aart J E; Furch, Alexandra C U

    2013-01-01

    Collection of cucurbit exudates from cut petioles has been a powerful tool for gaining knowledge on phloem sap composition without full notion of the complex exudation mechanism. Only few publications explicitly mentioned that exudates were collected from the basal side of the cut, which exudes more copiously than the apical side. This is surprising since only exudation from the apical side is supposedly driven by phloem pressure gradients. Composition of carbohydrates and pH values at both wounding sides are equal, whereas protein concentration is higher at the basal side. Apparently, exudation is far more complex than just the delivery of phloem sap. Xylem involvement is indicated by lower protein concentrations after elimination of root pressure. Moreover, dye was sucked into xylem vessels owing to relaxation of negative pressure after cutting. The lateral water efflux from the vessels increases turgor of surrounding cells including sieve elements. Simultaneously, detached parietal proteins (PP1/PP2) induce occlusion of sieve plates and cover wound surface. If root pressure is strong enough, pure xylem sap can be collected after removal of the occlusion plug at the wound surface. The present findings provide a mechanism of sap exudation in Cucurbita maxima, in which the contribution of xylem water is integrated. © 2012 Blackwell Publishing Ltd.

  2. Fine root dynamics of mature European beech (Fagus sylvatica L.) as influenced by elevated ozone concentrations

    International Nuclear Information System (INIS)

    Mainiero, Raphael; Kazda, Marian; Haeberle, Karl-Heinz; Nikolova, Petia Simeonova; Matyssek, Rainer

    2009-01-01

    Fine root dynamics (diameter < 1 mm) in mature Fagus sylvatica, with the canopies exposed to ambient or twice-ambient ozone concentrations, were investigated throughout 2004. The focus was on the seasonal timing and extent of fine root dynamics (growth, mortality) in relation to the soil environment (water content, temperature). Under ambient ozone concentrations, a significant relationship was found between fine root turnover and soil environmental changes indicating accelerated fine root turnover under favourable soil conditions. In contrast, under elevated ozone, this relationship vanished as the result of an altered temporal pattern of fine root growth. Fine root survival and turnover rate did not differ significantly between the different ozone regimes, although a delay in current-year fine root shedding was found under the elevated ozone concentrations. The data indicate that increasing tropospheric ozone levels can alter the timing of fine root turnover in mature F. sylvatica but do not affect the turnover rate. - Doubling of ozone concentrations in mature European beech affected the seasonal timing of fine root turnover rather than the turnover rate.

  3. Gravitropism interferes with hydrotropism via counteracting auxin dynamics in cucumber roots: clinorotation and spaceflight experiments.

    Science.gov (United States)

    Morohashi, Keita; Okamoto, Miki; Yamazaki, Chiaki; Fujii, Nobuharu; Miyazawa, Yutaka; Kamada, Motoshi; Kasahara, Haruo; Osada, Ikuko; Shimazu, Toru; Fusejima, Yasuo; Higashibata, Akira; Yamazaki, Takashi; Ishioka, Noriaki; Kobayashi, Akie; Takahashi, Hideyuki

    2017-09-01

    Roots of land plants show gravitropism and hydrotropism in response to gravity and moisture gradients, respectively, for controlling their growth orientation. Gravitropism interferes with hydrotropism, although the mechanistic aspects are poorly understood. Here, we differentiated hydrotropism from gravitropism in cucumber roots by conducting clinorotation and spaceflight experiments. We also compared mechanisms regulating hydrotropism and auxin-regulated gravitropism. Clinorotated or microgravity (μG)-grown cucumber seedling roots hydrotropically bent toward wet substrate in the presence of moisture gradients, but they grew straight in the direction of normal gravitational force at the Earth's surface (1G) on the ground or centrifuge-generated 1G in space. The roots appeared to become hydrotropically more sensitive to moisture gradients under μG conditions in space. Auxin transport inhibitors significantly reduced the hydrotropic response of clinorotated seedling roots. The auxin efflux protein CsPIN5 was differentially expressed in roots of both clinorotated and μG-grown seedlings; with higher expression in the high-humidity (concave) side than the low-humidity (convex) side of hydrotropically responding roots. Our results suggest that roots become hydrotropically sensitive in μG, and CsPIN5-mediated auxin transport has an important role in inducing root hydrotropism. Thus, hydrotropic and gravitropic responses in cucumber roots may compete via differential auxin dynamics established in response to moisture gradients and gravity. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

  4. Accumulation of cinnamic acid and vanillin in eggplant root ...

    African Journals Online (AJOL)

    The contents of cinnamic acid and vanillin in eggplant root exudates and soil were determined by HPLC. The results showed that cinnamic acid and vanillin might remain in soil after the root of eggplant is released. With the extending growth stage and planting year of eggplant, the contents in root exudates, rhizosphere and ...

  5. Fine root dynamics in moso bamboo and Japanese cedar forest by scanner method in central Taiwan

    Science.gov (United States)

    Chen, Zhi-Wei; Lin, Po-Hsuan; Kume, Tomonori

    2017-04-01

    Phyllostachys pubescens is one of the most important economic plant in the world. Phyllostachys pubescens originates from China and it had been introduced to neighbor countries about three hundred ago due to its economic value. But substantial bamboo forests were abandoned due to declines in demand. These unmanaged bamboo forests have been expanding to adjacent original forests in northern Taiwan. This vegetation alternation may not only decrease the local biodiversity but also affect the carbon cycle. Fine roots are responsible for water and nutrients acquisition and forming the most active part of the whole root system. The characteristics of fine roots are non-woody, small diameter and short lifespan. When roots keep producing new roots and replacing old roots, carbon and nutrients was transported into soil. Consequently, fine root production is one of the important component to understand the below-ground carbon cycle. However, there is few studies about fine root production in moso bamboo forests. We still lack effective method to obtain quantitative and objective data in Taiwan. It severely limits us to understand the below-ground carbon dynamics there. Minirhizotrons method has been used to investigate fine root dynamics by inserting transparent tubes into soil and by comparing changes in root length in images taken by micro-camera. But this method has some shortcomings; i.e. Most of image analysis are conducted manually and time-consuming. And it is difficult to estimate the stand level fine root production from small observation view. A new method "scanner method", which collect A4-size image (bigger than minirhizotrons) can overcome some parts of the shortcoming of minirhizotrons. The transparent acrylic box with A4-box view is inserted into soil and the interface between soil and box is scanned by commercial scanner. We can monitor the total projected root area, growth and decomposition separately by series of images. The primary objective of this study

  6. A mathematical model for investigating the effect of cluster roots on plant nutrient uptake

    KAUST Repository

    Zygalakis, K. C.; Roose, T.

    2012-01-01

    phase and can also solubilised due to citrate exudation. Using multiple scale homogenisation techniques we derive an effective model that accounts for the cumulative effect of citrate exudation and phosphate uptake by cluster roots whilst still retaining

  7. Dynamic root uptake model for neutral lipophilic organics

    DEFF Research Database (Denmark)

    Trapp, Stefan

    2002-01-01

    and output to stem with the transpiration stream plus first-order metabolism and dilution by exponential growth. For chemicals with low or intermediate lipophilicity (log Kow , 2), there was no relevant difference between dynamic model and equilibrium approach. For lipophilic compounds, the dynamic model...

  8. Effects of Infection by Belonolaimus longicaudatus on Rooting Dynamics among St. Augustinegrass and Bermudagrass Genotypes.

    Science.gov (United States)

    Aryal, Sudarshan K; Crow, William T; McSorley, Robert; Giblin-Davis, Robin M; Rowland, Diane L; Poudel, Bishow; Kenworthy, Kevin E

    2015-12-01

    Understanding rooting dynamics using the minirhizotron technique is useful for cultivar selection and to quantify nematode damage to roots. A 2-yr microplot study including five bermudagrass ('Tifway', Belonolaimus longicaudatus susceptible; two commercial cultivars [TifSport and Celebration] and two genotypes ['BA132' and 'PI 291590'], which have been reported to be tolerant to B. longicaudatus) and two St. Augustinegrass ('FX 313', susceptible, and 'Floratam' that was reported as tolerant to B. longicaudatus) genotypes in a 5 x 2 and 2 x 2 factorial design with four replications, respectively, was initiated in 2012. Two treatments included were uninoculated and B. longicaudatus inoculated. In situ root images were captured each month using a minirhizotron camera system from April to September of 2013 and 2014. Mixed models analysis and comparison of least squares means indicated significant differences in root parameters studied across the genotypes and soil depths of both grass species. 'Celebration', 'TifSport' and 'PI 291590' bermudagrass, and 'Floratam' St. Augustinegrass had significantly different root parameters compared to the corresponding susceptible genotypes (P ≤ 0.05). Only 'TifSport' had no significant root loss when infested with B. longicaudatus compared to non-infested. 'Celebration' and 'PI 291590' had significant root loss but retained significantly greater root densities than 'Tifway' in B. longicaudatus-infested conditions (P ≤ 0.05). Root lengths were greater at the 0 to 5 cm depth followed by 5 to 10 and 10 to 15 cm of vertical soil depth for both grass species (P ≤ 0.05). 'Celebration', 'TifSport', and 'PI 291590' had better root vigor against B. longicaudatus compared to Tifway.

  9. Graph Theory Roots of Spatial Operators for Kinematics and Dynamics

    Science.gov (United States)

    Jain, Abhinandan

    2011-01-01

    Spatial operators have been used to analyze the dynamics of robotic multibody systems and to develop novel computational dynamics algorithms. Mass matrix factorization, inversion, diagonalization, and linearization are among several new insights obtained using such operators. While initially developed for serial rigid body manipulators, the spatial operators and the related mathematical analysis have been shown to extend very broadly including to tree and closed topology systems, to systems with flexible joints, links, etc. This work uses concepts from graph theory to explore the mathematical foundations of spatial operators. The goal is to study and characterize the properties of the spatial operators at an abstract level so that they can be applied to a broader range of dynamics problems. The rich mathematical properties of the kinematics and dynamics of robotic multibody systems has been an area of strong research interest for several decades. These properties are important to understand the inherent physical behavior of systems, for stability and control analysis, for the development of computational algorithms, and for model development of faithful models. Recurring patterns in spatial operators leads one to ask the more abstract question about the properties and characteristics of spatial operators that make them so broadly applicable. The idea is to step back from the specific application systems, and understand more deeply the generic requirements and properties of spatial operators, so that the insights and techniques are readily available across different kinematics and dynamics problems. In this work, techniques from graph theory were used to explore the abstract basis for the spatial operators. The close relationship between the mathematical properties of adjacency matrices for graphs and those of spatial operators and their kernels were established. The connections hold across very basic requirements on the system topology, the nature of the component

  10. Dynamics of root and leaf decomposition in chronosequence of rubber plantation (Hevea brasilensis) in SW China

    International Nuclear Information System (INIS)

    Moazzam, N.S.; Yiping, Z.; Liqing, S.; Moazzam, N.S.

    2018-01-01

    This study highlighted the dynamics of stand parameters as well as root and leaf litter decomposition in the chronosequence (49, 32, 24 and 12 years old plantations established in the year 1965, 1982, 1990 and 2002) of the rubber plantation in Xishuangbanna SW China. Litter trappers were installed on the study site to collect the leaf litter and litter bag experiment was carried out to investigate the rate of root and leaf litter decomposition. The study revealed significant variation of stand characteristics during the decomposition process. The monthly litter fall and root biomass (all categories; kg m-3) showed positive correlation with stand characteristics and age. Remaining leaf litter mass % in the litter bags reduced with the passage of time and was significantly different in the chronosequence. The highest root decomposition rate (55%) was shown by fine roots and minimum (32%) by coarse roots during the study period. The investigations on elemental composition of the leaf and root provides basic important information for rate of nutrient cycle along with decomposition rate in rubber plantation and result are quite helpful for simulating the below ground carbon stock of rubber plantation in SW China. (author)

  11. Seasonal dynamics of structure and functional activity of ectomycorrhizal roots of the Siberian fir

    Directory of Open Access Journals (Sweden)

    T. A. Sizonenko

    2017-12-01

    Full Text Available The aim of our work was to study seasonal dynamics of the Siberian fir Abies sibirica Ledeb. ectomycorrhizal morpho-anatomical structure, respiration rate and fluorescence. The study was carried out in the bilberry-sphagnum spruce forest in the middle taiga of the Komi Republic, Russia. The morpho-anatomical structure and fluorescence parameters were studied by light and luminescence microscopy. Thin root respiration was studied in intact fine roots in the field using an infrared gas analyzer. 12 subtypes of fungal mantels were revealed in ectomycorrhizal fir roots; their amount and composition demonstrated seasonal dynamic changes. At the beginning vegetation stage, the diversity and proportion of pseudoparenchymatous and double covers were maximal. Plant component of ectomycorrhizae that includes cortical parenchyma and stele had high activity of fluorescence during the entire vegetation period. The dynamics of staining of fungal component (fungal mantel and Hartig net was more contrasting. The highest fluorescence intensity of cortical parenchyma was found in ectomycorrhizae with maximal fungal mantel thickness. High proportion of tannin cells in cortical parenchyma was related with low intensity of fungal mantel and Hartig net fluorescence. During vegetation season, maximal amount of intensively strained ectomycorrhizal elements occurred in July and unstrained – in June and August. Relation between fine roots respiration and an increase of brightly strained ectomycorrhizal structural elements in fir roots was not statistically significant. Root CO2-emission was lower in May and September in comparison with summer months. For respiration rate of fir fine roots we found its strong positive correlation with the litter temperature.

  12. Population Dynamics of Biota on the Roots of Azolla microphylla Kaulfuss

    Directory of Open Access Journals (Sweden)

    NITA ETIKAWATI

    2000-01-01

    Full Text Available Azolla was a special fern that their associations with Anabaena azollae able to fix free nitrogen from air, to produce protein. Although by the ages, biota diversity those habits on the roots of Azolla increased and effected to protein concentration. The research was to find out population dynamics of biota on the roots of Azolla microphylla Kaulfuss and the growth peak. This study used Completely Randomized Design with 10 kinds of biota, i.e. bacteria, Fungi, Actinomycetes, Protozoa, Alga, Crustacean, Rotifers, Coelenterate, Insect and Molluscs, and it was used 3 replications. Research was conducted within 4 weeks and the populations of biota were observed every week. Data were statistically analyzed using Analysis Variant and Duncan’s Multiple Range Test. The population dynamics of biota on the roots of Azolla microphylla Kaulfuss were influenced on its quantity and composition, and the growth peak is done in 2nd week.

  13. Arc root dynamics in high power plasma torches – Evidence of ...

    Indian Academy of Sciences (India)

    Two of the major causes of erratic and poor performance of a variety of thermal plasma processes are currently identified as the fluctuations arising out of the arc root movement on the electrodes inside the plasma torch and the fluid dynamic instabilities arising out of entrainment of the air into the plasma jet. This paper ...

  14. Population dynamics of host-specific root-feeding cyst nematode and resource quantity in the root zone of a clonal grass

    NARCIS (Netherlands)

    Stoel, C.D.; Duyts, H.; Putten, van der W.H.

    2006-01-01

    Recent studies have suggested that root-feeding nematodes influence plant community dynamics, but few studies have investigated the population dynamics of the nematodes. In coastal foredunes, feeding-specialist cyst nematodes (Heterodera spp.) are dominant in the soil nematode community and

  15. Population dynamics of a host-specific root-feeding cyst nematode and resource quantity in the root zone of a clonal grass

    NARCIS (Netherlands)

    Van der Stoel, C.D.; Duyts, H.; Van der Putten, W.H.

    2006-01-01

    Recent studies have suggested that root-feeding nematodes influence plant community dynamics, but few studies have investigated the population dynamics of the nematodes. In coastal foredunes, feeding-specialist cyst nematodes (Heterodera spp.) are dominant in the soil nematode community and

  16. The effect of mycorrhizal inoculation on hybrid poplar fine root dynamics in hydrocarbon contaminated soils

    Energy Technology Data Exchange (ETDEWEB)

    Gunderson, J.; Knight, J.D.; Van Rees, K.C.J. [Saskatchewan Univ., Saskatoon, SK (Canada). Dept. of Soil Science

    2006-07-01

    The biological remediation of contaminated soils using plants was discussed. Hybrid poplars are good candidates for phytoremediation because they root deeply, cycle large amounts of water and grow quickly. Their fine root system is pivotal in nutrient and water acquisition. Therefore, in order to maximize the phytoremediation potential, it is important to understand the response of the fine root system. In addition to degrading organic chemicals, ectomycorrhizal (ECM) fungi provide the host with greater access to nutrients. This study determined the relationship between residual soil hydrocarbons and soil properties at a field site. The effects of residual contamination on hybrid poplar fine root dynamics was also examined along with the effect of ectomycorrhizal colonization on hybrid poplar fine root dynamics when grown in diesel contaminated soil under controlled conditions. A minirhizotron camera inside a growth chamber captured images of mycorrhizal inoculation on hybrid poplar fine root production. Walker hybrid poplar seedlings were grown for 12 weeks in a control soil and also in a diesel contaminated soil. Seedlings were also grown in control and diesel contaminated, ectomycorrhizal inoculated soils. The inoculum was a mycorrhizal mix containing Pisolithus tinctorius and Rhizopogon spp. The images showed that colonization by ECM fungi increased hybrid poplar fine root production and aboveground biomass in a diesel contaminated soil compared to non-colonized trees in the same soil. Root:shoot ratios were much higher in the diesel contaminated/non-inoculated treatment than in either of the control soil treatments. Results of phytoremediation in diesel contaminated soil were better in the non-colonized treatment than in the colonized treatment. Both treatments removed more contaminants from the soil than the unplanted control. Much higher quantities of hydrocarbons were found sequestered in the roots from the inoculated treatment than from the non

  17. Marsh plant response to metals: Exudation of aliphatic low molecular weight organic acids (ALMWOAs)

    Science.gov (United States)

    Rocha, A. Cristina S.; Almeida, C. Marisa R.; Basto, M. Clara P.; Vasconcelos, M. Teresa S. D.

    2016-03-01

    Metal exposure is known to induce the production and secretion of substances, such as aliphatic low molecular weight organic acids (ALMWOAs), into the rhizosphere by plant roots. Knowledge on this matter is extensive for soil plants but still considerably scarce regarding marsh plants roots adapted to high salinity media. Phragmites australis and Halimione portulacoides, two marsh plants commonly distributed in European estuarine salt marshes, were used to assess the response of roots of both species, in terms of ALMWOAs exudation, to Cu, Ni and Cd exposure (isolated and in mixture since in natural environment, they are exposed to mixture of metals). As previous studies were carried out in unrealistic and synthetic media, here a more natural medium was selected. Therefore, in vitro experiments were carried out, with specimens of both marsh plants, and in freshwater contaminated with two different Cu, Ni and Cd concentrations (individual metal and in mixture). Both marsh plants were capable of liberating ALMWOAs into the surrounding medium. Oxalic, citric and maleic acids were found in P. australis root exudate solutions and oxalic and maleic acids in H. portulacoides root exudate solutions. ALMWOA liberation by both plants was plant species and metal-dependent. For instance, Cu affected the exudation of oxalic acid by H. portulacoides and of oxalic and citric acids by P. australis roots. In contrast, Ni and Cd did not stimulate any specific response. Regarding the combination of all metals, H. portulacoides showed a similar response to that observed for Cu individually. However, in the P. australis case, at high metal concentration mixture, a synergetic effect led to the increase of oxalic acid levels in root exudate solution and to a decrease of citric acid liberation. A correlation between ALMWOAs exudation and metal accumulation could not be established. P. australis and H. portulacoides are considered suitable metal phytoremediators of estuarine impacted areas

  18. Mycorrhizal Glomus spp. vary in their effects on the dynamics and turnover of fine alfalfa (Medicago sativa L.) roots

    International Nuclear Information System (INIS)

    Ren, A.; Waly, N.; Chunhui, M.; Zhang, Q.; Liu, H.; Yang, J.

    2016-01-01

    The distribution of fine roots in the soil profile has important implications related to water and nutrient uptake. The Objective of this study was to compare the effects of different arbuscular mycorrhizal fungi (AMF) on the fine root dynamics of Medicago sativa L. cv. Sanditi. We used minirhizotrons to observe changes in fine root length density (FRLD, mm/cm2) and fine root surface area density (FRSAD, mm2/cm2) during the growing season. Fine root P concentrations and turnover rate were also measured. The colonization rate of fine roots varied depending on the AMF species. Colonization rates were highest when roots were inoculated with Glomus mosseae and lowest when roots were inoculated G. intraradices. Inoculation with AMF significantly increased both FRLD and FRSAD. G. versiforme increased FRLD and FRSAD most, whereas G. mosseae had the least effect. Inoculation with AMF also decreased fine root turnover rates. Inoculation with a mixture of AMF species increased fine root turnover and P concentrations more than inoculation with a single AMF species. Fine root length density increased to a maximum on Aug. 6 and then decreased. In comparison, FRSAD exhibited two peaks during the growing season. Overall, the Results indicated that inoculation with AMF can significantly promote fine root growth and P uptake by alfalfa growing on soil with low P availability. The AMF may preserve fine root function late in the growing season. (author)

  19. Human impacts on soil carbon dynamics of deep-rooted Amazonian forests

    Science.gov (United States)

    Nepstad, Daniel C.; Stone, Thomas A.; Davidson, Eric A.

    1994-01-01

    Deforestation and logging degrade more forest in eastern and southern Amazonia than in any other region of the world. This forest alteration affects regional hydrology and the global carbon cycle, but our current understanding of these effects is limited by incomplete knowledge of tropical forest ecosystems. It is widely agreed that roots are concentrated near the soil surface in moist tropical forests, but this generalization incorrectly implies that deep roots are unimportant in water and C budgets. Our results indicate that half of the closed-canopy forests of Brazilian Amazonic occur where rainfall is highly seasonal, and these forests rely on deeply penetrating roots to extract soil water. Pasture vegetation extracts less water from deep soil than the forest it replaces, thus increasing rates of drainage and decreasing rates of evapotranspiration. Deep roots are also a source of modern carbon deep in the soil. The soils of the eastern Amazon contain more carbon below 1 m depth than is present in above-ground biomass. As much as 25 percent of this deep soil C could have annual to decadal turnover times and may be lost to the atmosphere following deforestation. We compared the importance of deep roots in a mature, evergreen forest with an adjacent man-made pasture, the most common type of vegetation on deforested land in Amazonia. The study site is near the town of Paragominas, in the Brazilian state of Para, with a seasonal rainfall pattern and deeply-weathered, kaolinitic soils that are typical for large portions of Amazonia. Root distribution, soil water extraction, and soil carbon dynamics were studied using deep auger holes and shafts in each ecosystem, and the phenology and water status of the leaf canopies were measured. We estimated the geographical distribution of deeply-rooting forests using satellite imagery, rainfall data, and field measurements.

  20. Two-photon Photoactivation to Measure Histone Exchange Dynamics in Plant Root Cells.

    Science.gov (United States)

    Rosa, Stefanie; Shaw, Peter

    2015-10-20

    Chromatin-binding proteins play a crucial role in chromatin structure and gene expression. Direct binding of chromatin proteins both maintains and regulates transcriptional states. It is therefore important to study the binding properties of these proteins in vivo within the natural environment of the nucleus. Photobleaching, photoactivation and photoconversion (photoswitching) can provide a non-invasive experimental approach to study dynamic properties of living cells and organisms. We used photoactivation to determine exchange dynamics of histone H2B in plant stem cells of the root (Rosa et al. , 2014). The stem cells of the root are located in the middle of the tissue, which made it impossible to carry out photoactivation of sufficiently small and well-defined sub-cellular regions with conventional laser illumination in the confocal microscope, mainly because scattering and refraction effects within the root tissue dispersed the focal spot and caused photoactivation of too large a region. We therefore used 2-photon activation, which has much better inherent resolution of the illuminated region. This is because the activation depends on simultaneous absorption of two or more photons, which in turns depends on the square (or higher power) of the intensity-a much sharper peak. In this protocol we will describe the experimental procedure to perform two-photon photoactivation experiments and the corresponding image analysis. This protocol can be used for nuclear proteins tagged with photoactivable GFP (PA-GFP) expressed in root tissues.

  1. Growth dynamics of fine roots in a coniferous fern forest site close to Forsmark in the central part of Sweden

    International Nuclear Information System (INIS)

    Persson, Hans; Stadenberg, Ingela

    2007-12-01

    The seasonal growth dynamics of live and dead roots for trees and the field layer species (g/m 2 , varying diameter fractions) and live/dead ratios were analysed at a fresh/moist coniferous fern forest site close to the nuclear power plant at Forsmark in the central eastern parts of Sweden. The changes in depth distribution of fine roots were observed at depth intervals of the top humus horizon down to 40 cm in the mineral soil profile. The bulk of living fine roots of trees ( 2 . The total quantity of fine roots (live + dead) amounted to 543, 434, 314 and 546 g/m 2 . Considerable quantities of fine roots (< 1 mm in diameter) were attributed to field-layer species (about 18% of the total biomass during the whole period of investigation). The turnover rate (the rate of construction of new roots) for tree fine roots < 1 mm in diameter amounted to at least the size of the average fine-root biomass. Our methods of estimating fine-root production and mortality, involved periodic measurements of live and dead dry weight of the fine roots from sequential core samples of the forest soil. The collected data give a proper and instant measure of the spatial and temporal distribution of fine roots in the undisturbed soil-profile. Data from other fine-root investigations suggest turnover rates in agreement with our present findings. Differences between root growth and turnover should be expected between trees of different age, tree species and different forest sites, but also between different years. Substantial variations in fine-root biomass, necromass and live/dead ratios are found in different forest sites. Correct methods for estimating the amount of live and dead fine-roots in the soil at regular time intervals are essential for any calculation of fine-root turnover. Definition of root vitality differs in literature, making it difficult to compare results from different root investigators. Our investigation clarifies the importance of using distinct morphological criteria

  2. Exudate gums: occurrence, production, and applications.

    Science.gov (United States)

    Verbeken, D; Dierckx, S; Dewettinck, K

    2003-11-01

    This paper presents a review of the industrially most relevant exudate gums: gum arabic, gum karya, and gum tragacanth. Exudate gums are obtained as the natural exudates of different tree species and exhibit unique properties in a wide variety of applications. This review covers the chemical structure, occurrence and production of the different gums. It also deals with the size and relative importance of the various players on the world market. Furthermore, it gives an overview of the main application fields of the different gums, both food and non-food.

  3. Evaluation of detectability of right inferior phrenic artery root in dynamic CT

    Energy Technology Data Exchange (ETDEWEB)

    Sato, Osamu [Akashi Municipal Hospital, Hyogo (Japan); Kizu, Osamu; Shimizu, Toshihisa; Takahashi, Takeshi; Ohno, Koji; Ohmura, Makoto; Maeda, Tomoho

    1995-05-01

    We evaluated the detectability of the root of the right inferior phrenic artery in dynamic CT over the entire liver as used for the diagnosis of hepatocellular carcinoma. The results showed no detection in three cases, poor detection in seven, detection in 12 and good detection in eight. The right inferior phrenic artery could be detected in many cases. Identification was easier in cases with direct branching from the aorta. It can be concluded that for angiographic examination, dynamic CT over the entire liver is useful for catheterization to the right inferior phrenic artery. (author).

  4. Evaluation of detectability of right inferior phrenic artery root in dynamic CT

    International Nuclear Information System (INIS)

    Sato, Osamu; Kizu, Osamu; Shimizu, Toshihisa; Takahashi, Takeshi; Ohno, Koji; Ohmura, Makoto; Maeda, Tomoho.

    1995-01-01

    We evaluated the detectability of the root of the right inferior phrenic artery in dynamic CT over the entire liver as used for the diagnosis of hepatocellular carcinoma. The results showed no detection in three cases, poor detection in seven, detection in 12 and good detection in eight. The right inferior phrenic artery could be detected in many cases. Identification was easier in cases with direct branching from the aorta. It can be concluded that for angiographic examination, dynamic CT over the entire liver is useful for catheterization to the right inferior phrenic artery. (author)

  5. Dynamics in the tomato root transcriptome on infection with the potato cyst nematode Globodera rostochiensis.

    Science.gov (United States)

    Swiecicka, Magdalena; Filipecki, Marcin; Lont, Dieuwertje; Van Vliet, Joke; Qin, Ling; Goverse, Aska; Bakker, Jaap; Helder, Johannes

    2009-07-01

    Plant parasitic nematodes infect roots and trigger the formation of specialized feeding sites by substantial reprogramming of the developmental process of root cells. In this article, we describe the dynamic changes in the tomato root transcriptome during early interactions with the potato cyst nematode Globodera rostochiensis. Using amplified fragment length polymorphism-based mRNA fingerprinting (cDNA-AFLP), we monitored 17 600 transcript-derived fragments (TDFs) in infected and uninfected tomato roots, 1-14 days after inoculation with nematode larvae. Six hundred and twenty-four TDFs (3.5%) showed significant differential expression on nematode infection. We employed GenEST, a computer program which links gene expression profiles generated by cDNA-AFLP and databases of cDNA sequences, to identify 135 tomato sequences. These sequences were grouped into eight functional categories based on the presence of genes involved in hormone regulation, plant pathogen defence response, cell cycle and cytoskeleton regulation, cell wall modification, cellular signalling, transcriptional regulation, primary metabolism and allocation. The presence of unclassified genes was also taken into consideration. This article describes the responsiveness of numerous tomato genes hitherto uncharacterized during infection with endoparasitic cyst nematodes. The analysis of transcriptome profiles allowed the sequential order of expression to be dissected for many groups of genes and the genes to be connected with the biological processes involved in compatible interactions between the plant and nematode.

  6. Temporal dynamic responses of roots in contrasting tomato genotypes to cadmium tolerance.

    Science.gov (United States)

    Borges, Karina Lima Reis; Salvato, Fernanda; Alcântara, Berenice Kussumoto; Nalin, Rafael Storto; Piotto, Fernando Ângelo; Azevedo, Ricardo Antunes

    2018-04-01

    Despite numerous studies on cadmium (Cd) uptake and accumulation in crops, relatively little is available considering the temporal dynamic of Cd uptake and responses to stress focused on the root system. Here we highlighted the responses to Cd-induced stress in roots of two tomato genotypes contrasting in Cd-tolerance: the tolerant Pusa Ruby and the sensitive Calabash Rouge. Tomato genotypes growing in the presence of 35 μM CdCl 2 exhibited a similar trend of Cd accumulation in tissues, mainly in the root system and overall plants exhibited reduction in the dry matter weight. Both genotypes showed similar trends for malondialdehyde and hydrogen peroxide accumulation with increases when exposed to Cd, being this response more pronounced in the sensitive genotype. When the antioxidant machinery is concerned, in the presence of Cd the reduced glutathione content was decreased in roots while ascorbate peroxidase (APX), glutathione reductase (GR) and glutathione S-transferase (GST) activities were increased in the presence of Cd in the tolerant genotype. Altogether these results suggest APX, GR and GST as the main players of the antioxidant machinery against Cd-induced oxidative stress.

  7. Root causes occurrence of low BIM adoption in Malaysia: System dynamics modelling approach

    Science.gov (United States)

    Mamter, Shahela; Aziz, Abdul Rashid Abdul; Zulkepli, Jafri

    2017-11-01

    The global implementation of BIM in the construction field is increasing worldwide. Due to the advantages offered by BIM, its implementation is considered important in the construction projects. Nevertheless, the Construction Industry Transformation Plan has reported that the adoption of Building Information Modelling (BIM) in Malaysia is still low and it is estimated at only 10 percent adoption amongst construction stake players. The barriers influencing the occurrence of low adoption BIM in Malaysia have been studied by some researchers. However, these researchers did not investigate the root causes which might lead to the recurring of the barriers to BIM adoption. Root causes that immediately occurrence of barriers, also known as precipitants or trigger causes. This conceptual paper developed the causal loop diagram (CLD) which presents the relationship between the perceived variables using system dynamic modelling approach. The findings revealed a novelty validated diagrams that design the holistic dynamic relationship on the root causes occurrence of low BIM adoption. Nonetheless, the diagram subject to more empirical testing for its practicability and further refinement upon more results expected to emerge as the research progresses.

  8. Subretinal lipid exudation associated with untreated choroidal melanoma

    Directory of Open Access Journals (Sweden)

    C K Minija

    2011-01-01

    Full Text Available Subretinal lipid exudation in an untreated choroidal melanoma is very rare. It is seen following plaque radiotherapy in choroidal melanoma. There is only one case report of untreated choroidal melanoma with massive lipid exudation in a patient with metastatic hypernephroma. We report here a rare case of untreated choroidal melanoma with lipid exudation. Subretinal exudation that is rarely seen following plaque brachytherapy was noted at the borders of this untreated tumor. Lipid exudation partially resolved following brachytherapy.

  9. Methylobacterium-plant interaction genes regulated by plant exudate and quorum sensing molecules

    Directory of Open Access Journals (Sweden)

    Manuella Nóbrega Dourado

    2013-12-01

    Full Text Available Bacteria from the genus Methylobacterium interact symbiotically (endophytically and epiphytically with different plant species. These interactions can promote plant growth or induce systemic resistance, increasing plant fitness. The plant colonization is guided by molecular communication between bacteria-bacteria and bacteria-plants, where the bacteria recognize specific exuded compounds by other bacteria (e.g. homoserine molecules and/or by the plant roots (e.g. flavonoids, ethanol and methanol, respectively. In this context, the aim of this study was to evaluate the effect of quorum sensing molecules (N-acyl-homoserine lactones and plant exudates (including ethanol in the expression of a series of bacterial genes involved in Methylobacterium-plant interaction. The selected genes are related to bacterial metabolism (mxaF, adaptation to stressful environment (crtI, phoU and sss, to interactions with plant metabolism compounds (acdS and pathogenicity (patatin and phoU. Under in vitro conditions, our results showed the differential expression of some important genes related to metabolism, stress and pathogenesis, thereby AHL molecules up-regulate all tested genes, except phoU, while plant exudates induce only mxaF gene expression. In the presence of plant exudates there is a lower bacterial density (due the endophytic and epiphytic colonization, which produce less AHL, leading to down regulation of genes when compared to the control. Therefore, bacterial density, more than plant exudate, influences the expression of genes related to plant-bacteria interaction.

  10. Fine root dynamics in lodgepole pine and white spruce stands along productivity gradients in reclaimed oil sands sites.

    Science.gov (United States)

    Jamro, Ghulam Murtaza; Chang, Scott X; Naeth, M Anne; Duan, Min; House, Jason

    2015-10-01

    Open-pit mining activities in the oil sands region of Alberta, Canada, create disturbed lands that, by law, must be reclaimed to a land capability equivalent to that existed before the disturbance. Re-establishment of forest cover will be affected by the production and turnover rate of fine roots. However, the relationship between fine root dynamics and tree growth has not been studied in reclaimed oil sands sites. Fine root properties (root length density, mean surface area, total root biomass, and rates of root production, turnover, and decomposition) were assessed from May to October 2011 and 2012 using sequential coring and ingrowth core methods in lodgepole pine (Pinus contorta Dougl.) and white spruce (Picea glauca (Moench.) Voss) stands. The pine and spruce stands were planted on peat mineral soil mix placed over tailings sand and overburden substrates, respectively, in reclaimed oil sands sites in Alberta. We selected stands that form a productivity gradient (low, medium, and high productivities) of each tree species based on differences in tree height and diameter at breast height (DBH) increments. In lodgepole pine stands, fine root length density and fine root production, and turnover rates were in the order of high > medium > low productivity sites and were positively correlated with tree height and DBH and negatively correlated with soil salinity (P < 0.05). In white spruce stands, fine root surface area was the only parameter that increased along the productivity gradient and was negatively correlated with soil compaction. In conclusion, fine root dynamics along the stand productivity gradients were closely linked to stand productivity and were affected by limiting soil properties related to the specific substrate used for reconstructing the reclaimed soil. Understanding the impact of soil properties on fine root dynamics and overall stand productivity will help improve land reclamation outcomes.

  11. Changes of organic acid exudation and rhizosphere pH in rice plants under chromium stress

    International Nuclear Information System (INIS)

    Zeng Fanrong; Chen Song; Miao Ying; Wu Feibo; Zhang Guoping

    2008-01-01

    The effect of chromium (Cr) stress on the changes of rhizosphere pH, organic acid exudation, and Cr accumulation in plants was studied using two rice genotypes differing in grain Cr accumulation. The results showed that rhizosphere pH increased with increasing level of Cr in the culture solution and with an extended time of Cr exposure. Among the six organic acids examined in this experiment, oxalic and malic acid contents were relatively higher, and had a significant positive correlation with the rhizosphere pH, indicating that they play an important role in changing rhizosphere pH. The Cr content in roots was significantly higher than that in stems and leaves. Cr accumulation in plants was significantly and positively correlated with rhizosphere pH, and the exudation of oxalic, malic and citric acids, suggesting that an increase in rhizosphere pH, and exudation of oxalic, malic and citric acid enhances Cr accumulation in rice plants. - Rhizosphere pH and organic acid exudation of rice roots are markedly affected by chromium level in culture solution

  12. Dynamic Model of a Rotating Flexible Arm-Flexible Root Mechanism Driven by a Shaft Flexible in Torsion

    Directory of Open Access Journals (Sweden)

    S.Z. Ismail

    2006-01-01

    Full Text Available This paper presents a dynamic model of a rotating flexible beam carrying a payload at its tip. The model accounts for the driving shaft and the arm root flexibilities. The finite element method and the Lagrangian dynamics are used in deriving the equations of motion with the small deformation theory assumptions and the Euler-Bernoulli beam theory. The obtained model is a nonlinear-coupled system of differential equations. The model is simulated for different combinations of shaft and root flexibilities and arm properties. The simulation results showed that the root flexibility is an important factor that should be considered in association with the arm and shaft flexibilities, as its dynamics influence the motor motion. Moreover, the effect of system non-linearity on the dynamic behavior is investigated by simulating the equivalent linearized system and it was found to be an important factor that should be considered, particularly when designing a control strategy for practical implementation.

  13. Amino acids in root exudates of Ambrosia artemisiifolia

    Czech Academy of Sciences Publication Activity Database

    Hohnová, Barbora; Moravcová, Dana; Figala, J.; Lvončík, S.; Lojková, Lea; Formánek, P.

    2015-01-01

    Roč. 47, AUG (2015), s. 1691-1691 ISSN 0939-4451. [International Congress on Amino Acids, Peptides and Proteins /14./. 03.08.2015-07.08.2015, Vienna] Institutional support: RVO:68081715 Keywords : PHWE * GC-MS * SDS-PAGE Subject RIV: CB - Analytical Chemistry, Separation

  14. Allelopathy of root exudates from different resistant eggplants to ...

    African Journals Online (AJOL)

    Three eggplant cultivars were inoculated with Verticillium dahliae Kleb. to assess their resistance to Verticillium wilt. Solanum tor was resistant, “Liyuanziqie” was tolerant, and “Xi'anlvqie” susceptible. The disease incidence and disease index of Verticillium wilt and the amount of V. dahliae in rhizospheric soil, variation of ...

  15. Simulating Root Density Dynamics and Nitrogen Uptake – Can a Simple Approach be Sufficient?

    OpenAIRE

    Pedersen, Anders; Zhang, Kefeng; Jensen, Lars Stoumann; Thorup-Kristensen, Kristian

    2007-01-01

    The modeling of root growth in many plant–soil models is simple and with few possibilities to adapt simulated root proliferation and depth distribution to that actually found with different crop species. Here we propose a root model, developed to describe root growth, root density and nitrogen uptake. The model focuses on annual crops, and attempts to model root growth of different crop species and row crops and its significance for nitrogen uptake from different parts of the soil volume.

  16. Dynamics of organic matters in the root-rhizoplane-soil system of maize [Zea mays], 1: A simple and rapid method for measuring root respiration

    Energy Technology Data Exchange (ETDEWEB)

    Okada, K. [Tokyo Univ., Tokyo (Japan); Kumura, A.

    1990-03-15

    In the analysis of dynamics of organic matter in the root-rhizoplane-soil system, it is essential to estimate various kinds of carbon flows in the system separately. Since a simple and rapid method for measuring root respiration was needed for this purpose, the authors developed the following method. A plastic syringe is used as the chamber. Sample roots are put into a syringe, in which the air is replaced with air of known CO{sub 2} concentration and the syringe is kept at a constant temperature for a certain time. A volume of the air in the syringe is injected into the flow of N{sub 2} gas in the tube which is connected to an infrared gas analyzer. The CO{sub 2} concentration in the syringe is directly related to the reading of the analyzer. From the difference of the CO{sub 2} concentration in the syringe before and after the incubation, the respiration rate of the roots is calculated. The details of the procedure were determined by the results of experiments regarding the effects of factors concerned. (author)

  17. Naturally-assisted metal phytoextraction by Brassica carinata: Role ofroot exudates

    International Nuclear Information System (INIS)

    Quartacci, Mike F.; Irtelli, Barbara; Gonnelli, Cristina; Gabbrielli, Roberto; Navari-Izzo, Flavia

    2009-01-01

    Due to relatively high chelant dosages and potential environmental risks it is necessary to explore different approaches in the remediation of metal-contaminated soils. The present study focussed on the removal of metals (As, Cd, Cu, Pb and Zn) from a multiple metal-contaminated soil by growing Brassica carinata plants in succession to spontaneous metallicolous populations of Pinus pinaster, Plantago lanceolata and Silene paradoxa. The results showed that the growth of the metallicolous populations increased the extractable metal levels in the soil, which resulted in a higher accumulation of metals in the above-ground parts of B. carinata. Root exudates of the three metallicolous species were analysed to elucidate their possible role in the enhanced metal availability. The presence of metals stimulated the exudation of organic and phenolic acids as well as flavonoids. It was suggested that root exudates played an important role in solubilising metals in soil and in favouring their uptake by roots. - Phytoextraction of metals is enhanced in Brassica carinata grown in succession to metallicolous populations of spontaneous species.

  18. Naturally-assisted metal phytoextraction by Brassica carinata: Role ofroot exudates

    Energy Technology Data Exchange (ETDEWEB)

    Quartacci, Mike F., E-mail: mfquart@agr.unipi.i [Dipartimento di Chimica e Biotecnologie Agrarie, Universita di Pisa, Via del Borghetto 80, 56124 Pisa (Italy); Irtelli, Barbara [Dipartimento di Chimica e Biotecnologie Agrarie, Universita di Pisa, Via del Borghetto 80, 56124 Pisa (Italy); Gonnelli, Cristina; Gabbrielli, Roberto [Dipartimento di Biologia Vegetale, Sezione di Ecologia e Fisiologia Vegetale, Universita di Firenze, Via Micheli 1, 50121 Firenze (Italy); Navari-Izzo, Flavia [Dipartimento di Chimica e Biotecnologie Agrarie, Universita di Pisa, Via del Borghetto 80, 56124 Pisa (Italy)

    2009-10-15

    Due to relatively high chelant dosages and potential environmental risks it is necessary to explore different approaches in the remediation of metal-contaminated soils. The present study focussed on the removal of metals (As, Cd, Cu, Pb and Zn) from a multiple metal-contaminated soil by growing Brassica carinata plants in succession to spontaneous metallicolous populations of Pinus pinaster, Plantago lanceolata and Silene paradoxa. The results showed that the growth of the metallicolous populations increased the extractable metal levels in the soil, which resulted in a higher accumulation of metals in the above-ground parts of B. carinata. Root exudates of the three metallicolous species were analysed to elucidate their possible role in the enhanced metal availability. The presence of metals stimulated the exudation of organic and phenolic acids as well as flavonoids. It was suggested that root exudates played an important role in solubilising metals in soil and in favouring their uptake by roots. - Phytoextraction of metals is enhanced in Brassica carinata grown in succession to metallicolous populations of spontaneous species.

  19. Genetics Home Reference: familial exudative vitreoretinopathy

    Science.gov (United States)

    ... A characteristic of X-linked inheritance is that fathers cannot pass X-linked traits to their sons. ... Resources (2 links) GeneReview: Familial Exudative Vitreoretinopathy, Autosomal Dominant GeneReview: NDP-Related Retinopathies General Information from MedlinePlus ( ...

  20. Abscisic acid dynamics in roots detected with genetically encoded FRET sensors

    Science.gov (United States)

    Jones, Alexander M; Danielson, Jonas ÅH; ManojKumar, Shruti N; Lanquar, Viviane; Grossmann, Guido; Frommer, Wolf B

    2014-01-01

    Cytosolic hormone levels must be tightly controlled at the level of influx, efflux, synthesis, degradation and compartmentation. To determine ABA dynamics at the single cell level, FRET sensors (ABACUS) covering a range ∼0.2–800 µM were engineered using structure-guided design and a high-throughput screening platform. When expressed in yeast, ABACUS1 detected concentrative ABA uptake mediated by the AIT1/NRT1.2 transporter. Arabidopsis roots expressing ABACUS1-2µ (Kd∼2 µM) and ABACUS1-80µ (Kd∼80 µM) respond to perfusion with ABA in a concentration-dependent manner. The properties of the observed ABA accumulation in roots appear incompatible with the activity of known ABA transporters (AIT1, ABCG40). ABACUS reveals effects of external ABA on homeostasis, that is, ABA-triggered induction of ABA degradation, modification, or compartmentation. ABACUS can be used to study ABA responses in mutants and quantitatively monitor ABA translocation and regulation, and identify missing components. The sensor screening platform promises to enable rapid fine-tuning of the ABA sensors and engineering of plant and animal hormone sensors to advance our understanding of hormone signaling. DOI: http://dx.doi.org/10.7554/eLife.01741.001 PMID:24737862

  1. The role of deep nitrogen and dynamic rooting profiles on vegetation dynamics and productivity in response to permafrost thaw and climate change in Arctic tundra

    Science.gov (United States)

    Hewitt, R. E.; Helene, G.; Taylor, D. L.; McGuire, A. D.; Mack, M. C.

    2017-12-01

    The release of permafrost-derived nitrogen (N) has the potential to fertilize tundra vegetation, modulating plant competition, stimulating productivity, and offsetting carbon losses from thawing permafrost. Dynamic rooting, mycorrhizal interactions, and coupling of N availability and root N uptake have been identified as gaps in ecosystem models. As a first step towards understanding whether Arctic plants can access deep permafrost-derived N, we characterized rooting profiles and quantified acquisition of 15N tracer applied at the permafrost boundary by moist acidic tundra plants subjected to almost three decades of warming at Toolik Lake, Alaska. In the ambient control plots the vegetation biomass is distributed between five plant functional types (PFTs): sedges, evergreen and deciduous shrubs, mosses and in lower abundance, forbs. The warming treatment has resulted in the increase of deciduous shrub biomass and the loss of sedges, evergreen shrubs, and mosses. We harvested roots by depth increment down to the top of the permafrost. Roots were classified by size class and PFT. The average thaw depth in the warmed plots was 58.3 cm ± 6.4 S.E., close to 18 cm deeper than the average thaw depth in the ambient plots (40.8 cm ± 1.8 S.E.). Across treatments the deepest rooting species was Rubus chamaemorus (ambient 40.8 cm ± 1.8 S.E., warmed 50.3 cm ± 9.8 S.E.), a non-mycorrhizal forb, followed by Eriophorum vaginatum, a non-mycorrhizal sedge. Ectomycorrhizal deciduous and ericoid mycorrhizal evergreen shrubs were rooted at more shallow depths. Deeply rooted non-mycorrhizal species had the greatest uptake of 15N tracer within 24 hours across treatments. Tracer uptake was greatest for roots of E. vaginatum in ambient plots and R. chamaemorus in warmed plots. Root profiles were integrated into a process-based ecosystem model coupled with a dynamic vegetation model. Functions modeling dynamic rooting profile relative to thaw depth were implemented for each PFT. The

  2. Calcium dynamics in root cells of Arabidopsis thaliana visualized with selective plane illumination microscopy.

    Directory of Open Access Journals (Sweden)

    Alex Costa

    Full Text Available Selective Plane Illumination Microscopy (SPIM is an imaging technique particularly suited for long term in-vivo analysis of transparent specimens, able to visualize small organs or entire organisms, at cellular and eventually even subcellular resolution. Here we report the application of SPIM in Calcium imaging based on Förster Resonance Energy Transfer (FRET. Transgenic Arabidopsis plants expressing the genetically encoded-FRET-based Ca(2+ probe Cameleon, in the cytosol or nucleus, were used to demonstrate that SPIM enables ratiometric fluorescence imaging at high spatial and temporal resolution, both at tissue and single cell level. The SPIM-FRET technique enabled us to follow nuclear and cytosolic Ca(2+ dynamics in Arabidopsis root tip cells, deep inside the organ, in response to different stimuli. A relevant physiological phenomenon, namely Ca(2+ signal percolation, predicted in previous studies, has been directly visualized.

  3. Differential exudation of two benzoxazinoids--one of the determining factors for seedling allelopathy of Triticeae species.

    Science.gov (United States)

    Belz, Regina G; Hurle, Karl

    2005-01-26

    Benzoxazinoids (Bx) are natural phytotoxins that function as chemical defense compounds in several species. The release of Bx by intact plant roots associated these compounds with root allelopathy in Triticeae species; however, the significance of exudate concentrations of Bx for plant-plant interactions is still a controversial question. A biological screening of 146 cultivars of four Triticeae species (Triticum aestivum L., Triticum durum Desf., Triticum spelta L., and Secale cereale L.) demonstrated a high cultivar dependence to suppress the root growth of Sinapis alba L. by root allelopathy in a dose-response bioassay. Only a few cultivars possessed a marked high or low allelopathic activity, whereby high-performance liquid chromatography-diode array detection analysis of root exudates revealed that these cultivars differed considerably in their ability to exude the two Bx aglucones, DIBOA [2,4-dihydroxy-2H-1,4-benzoxazin-3(4H)-one] and DIMBOA [2,4-dihydroxy-7-methoxy-2H-1,4-benzoxazin-3(4H)-one]. The total amount of DIBOA and DIMBOA exuded showed a significant correlation to the growth inhibition in bioassay with a statistically estimated contribution to the overall allelopathic effect of 48-72%. In a bioassay with pure phytotoxins, Bx concentrations consistent with the amounts quantified in the screening bioassay caused detrimental effects on S. alba and almost reproduced the statistically estimated contribution. The observed causal association between the allelopathic activity under laboratory conditions and the exudate concentrations of Bx suggests that this association might have implications for the interference of Triticeae species in natural plant communities.

  4. Irrigant flow in the root canal: experimental validation of an unsteady Computational Fluid Dynamics model using high-speed imaging.

    Science.gov (United States)

    Boutsioukis, C; Verhaagen, B; Versluis, M; Kastrinakis, E; van der Sluis, L W M

    2010-05-01

    To compare the results of a Computational Fluid Dynamics (CFD) simulation of the irrigant flow within a prepared root canal, during final irrigation with a syringe and a needle, with experimental high-speed visualizations and theoretical calculations of an identical geometry and to evaluate the effect of off-centre positioning of the needle inside the root canal. A CFD model was created to simulate irrigant flow from a side-vented needle inside a prepared root canal. Calculations were carried out for four different positions of the needle inside a prepared root canal. An identical root canal model was made from poly-dimethyl-siloxane (PDMS). High-speed imaging of the flow seeded with particles and Particle Image Velocimetry (PIV) were combined to obtain the velocity field inside the root canal experimentally. Computational, theoretical and experimental results were compared to assess the validity of the computational model. Comparison between CFD computations and experiments revealed good agreement in the velocity magnitude and vortex location and size. Small lateral displacements of the needle inside the canal had a limited effect on the flow field. High-speed imaging experiments together with PIV of the flow inside a simulated root canal showed a good agreement with the CFD model, even though the flow was unsteady. Therefore, the CFD model is able to predict reliably the flow in similar domains.

  5. Characterization of diverse soybean genotypes using 14 carbon for organic acid exudation under phosphorus stress and its relationship with phosphorus acquisition efficiency

    International Nuclear Information System (INIS)

    Vengavasi, Krishnapriya; Pandey, Renu

    2017-01-01

    To characterise the physiological aspects influencing organic acid exudation under low phosphorus (P) stress, experiment was conducted to screen a diverse soybean panel (comprising 116 genotypes) for total carbon exudation employing shoot labelling with 14 CO 2 technique. Among the traits measured at seedling stage, total carbon ( 14 C) exudation, P uptake and total dry weight contributed to the maximum genotypic variability in soybean. The proportion of organic acids (including oxalate, citrate, succinate and fumarate) was the highest among root-exuded compounds induced by low P stress in soybean. Improved root length, surface area and volume coupled with higher activity of enzymes in TCA cycle contributed to enhanced organic acid exudation under low P. Efficient soybean genotypes (EC-232019 and G-2344) exhibited superior growth and P acquisition efficiency under low soil P availability attributed to its higher root exudation potential aiding in mining fixed soil P. To understand the molecular mechanism differentially regulating root exudation potential in contrasting genotypes (EC-232019 and EC-113396), root proteome analysis at low P stress was carried out. Among the total proteins visualised by 2D-gel electrophoresis, 105 genotypes (32%) were differentially expressed between sufficient and low P levels. A total of 44 (14%) proteins were down-regulated by more than two-fold while 61 (15%) proteins were up-regulated by more than two-fold at low P. The differential proteins were involved in a myriad of functions including organic acid accumulation, carbohydrate, protein and lipid metabolism under low P stress. Characterisation of 17 proteins with unknown function indicated the role of novel genes under low P stress. The identified genotypes have potential to be used as donors in crop improvement programs to develop high-yielding P-efficient cultivars which may be an asset to low-input sustainable agriculture. (author)

  6. Growth dynamics of fine roots in a coniferous fern forest site close to Forsmark in the central part of Sweden

    Energy Technology Data Exchange (ETDEWEB)

    Persson, Hans; Stadenberg, Ingela (SLU, Dept. of Ecology and Environmental Research, Uppsala (Sweden))

    2007-12-15

    The seasonal growth dynamics of live and dead roots for trees and the field layer species (g/m2, varying diameter fractions) and live/dead ratios were analysed at a fresh/moist coniferous fern forest site close to the nuclear power plant at Forsmark in the central eastern parts of Sweden. The changes in depth distribution of fine roots were observed at depth intervals of the top humus horizon down to 40 cm in the mineral soil profile. The bulk of living fine roots of trees (< 1 mm in diameter) were found in the mineral soil horizon the total profile down to 40 cm of the mineral soil, where 89, 82, 83 and 89% of the total amount in the whole profile were found. The upper 2.5 cm part of the humus layer contained 83, 81, 100 and 100% of all roots of the humus layer on the four different sampling occasions. High amounts of living fine roots were found in the upper 10 cm of the mineral soil horizon viz. 84, 76, 91 and 69% of the total mineral soil layer. Consequently, both the top soil horizons of the humus and the mineral soil layers were heavily penetrated by living fine roots. The highest proportion of living fine roots was found in the top 2.5 cm of the humus layer. Accordingly, the live/dead ratio of fine roots (< 1 mm in diameter) decreased from the top of the humus layer to the lower part of mineral soil horizon from 8.0-0.3, 0.8-0.2, 4.4-0.4 and 3.3-0.7 (g g-1) for the four sampling occasions, respectively. We concluded that the decrease in the live/ dead ratio was related to decreased vitality with depth of the fine roots in the soil profile. The highest live/dead ratio was found in the upper 2.5 cm of the humus layer for both the tree and field-layer species. This distribution pattern was most evident for tree fine roots < 1 mm in diameter. The mean fine-root biomass (live tissue < 1 mm in diameter) of tree species for the total profile varied on the four sampling occasions between 317, 113, 139 and 248 g m-2. The related fine root necromass (dead tissue

  7. Automated Root Tracking with "Root System Analyzer"

    Science.gov (United States)

    Schnepf, Andrea; Jin, Meina; Ockert, Charlotte; Bol, Roland; Leitner, Daniel

    2015-04-01

    Crucial factors for plant development are water and nutrient availability in soils. Thus, root architecture is a main aspect of plant productivity and needs to be accurately considered when describing root processes. Images of root architecture contain a huge amount of information, and image analysis helps to recover parameters describing certain root architectural and morphological traits. The majority of imaging systems for root systems are designed for two-dimensional images, such as RootReader2, GiA Roots, SmartRoot, EZ-Rhizo, and Growscreen, but most of them are semi-automated and involve mouse-clicks in each root by the user. "Root System Analyzer" is a new, fully automated approach for recovering root architectural parameters from two-dimensional images of root systems. Individual roots can still be corrected manually in a user interface if required. The algorithm starts with a sequence of segmented two-dimensional images showing the dynamic development of a root system. For each image, morphological operators are used for skeletonization. Based on this, a graph representation of the root system is created. A dynamic root architecture model helps to determine which edges of the graph belong to an individual root. The algorithm elongates each root at the root tip and simulates growth confined within the already existing graph representation. The increment of root elongation is calculated assuming constant growth. For each root, the algorithm finds all possible paths and elongates the root in the direction of the optimal path. In this way, each edge of the graph is assigned to one or more coherent roots. Image sequences of root systems are handled in such a way that the previous image is used as a starting point for the current image. The algorithm is implemented in a set of Matlab m-files. Output of Root System Analyzer is a data structure that includes for each root an identification number, the branching order, the time of emergence, the parent

  8. Nitrogen dynamics in the soil-plant system under deficit and partial root-zone drying irrigation strategies in potatoes

    DEFF Research Database (Denmark)

    Shahnazari, Ali; Ahmadi, Seyed Hamid; Lærke, Poul Erik

    2008-01-01

    Experiments were conducted in lysimeters with sandy soil under an automatic rain-out shelter to study the effects of subsurface drip irrigation treatments, full irrigation (FI), deficit irrigation (DI) and partial root-zone drying (PRD), on nitrogen (N) dynamics in the soil-plant system of potatoes...

  9. Production dynamics of fine roots in beech forests: possible mechanism of resource allocation between above- and below-ground production

    Science.gov (United States)

    Nakahata, R.; Osawa, A.; Naramoto, M.; Mizunaga, H.; Sato, M.

    2017-12-01

    The masting phenomenon that seed production has large annual variation with spatial synchrony appears generally in beeches. Therefore, net primary production and carbon allocation mechanism in beech forests may differ among several years in relation to annual variation of seed production. On the other hand, fine roots play key roles in carbon dynamics and nutrient and water acquisition of an ecosystem. Evaluation of fine root dynamics is essential to understand long-term dynamics of production in forest ecosystems. Moreover, the influence of mast seeding on resource allocation should be clarified in such beech forests. The aim of this study is to clarify possible relationships between the patterns of above- and below-ground production in relation to the masting events using observation data of litter fall and fine root dynamics. We applied the litter trap method and a minirhizotron method in a cool-temperate natural forest dominated by beech (Fagus crenata Blume). Ten litter traps were set from 2008 to 2016, then annual leaf and seed production were estimated. Four minirhizotron tubes were buried in Aug. 2008 and soil profiles were scanned monthly until Nov. 2016 during the periods of no snow covering. The scanned soil profiles were analyzed for calculating fine root production using the WinRHIZO Tron software. In the present study site, rich production of mast seeding occurred biennially and fine root production showed various seasonal patterns. There was no significant correlation between seed production and annual fine root production in the same year. However, seed production had a positive correlation with fine root production in autumn in the previous year and indicated a negative correlation with that in autumn in the current year. These results indicate that higher fine root production has led to increased nutrient acquisition, which resulted in rich seed production in the next year. It is also suppressed after the masting events due to shortage in

  10. Soil moisture causes dynamic adjustments to root reinforcement that reduce slope stability

    Science.gov (United States)

    Tristram C. Hales; Chelcy F. Miniat

    2017-01-01

    In steep soil-mantled landscapes, the initiation of shallow landslides is strongly controlled by the distribution of vegetation, whose roots reinforce the soil. The magnitude of root reinforcement depends on the number, diameter distribution, orientation and the mechanical properties of roots that cross potential failure planes. Understanding how these...

  11. Clinical case of exudative pleuritis in stallion

    International Nuclear Information System (INIS)

    Kanukov, D.; Petkov, P.; Stoyanchev, K.

    2001-01-01

    A casual exudative pleuritis in 2 years old stallion, Holsteiner breed, has been outlined. The disease is extremely rare in this country. Comprehensive examinations have been made during the period of hospitalization: daily clinical examinations, double renthgenography; regular haematological and biochemical tests; microbiological culture tests with an antibioticogram; laboratory tests of punctate and periodical ultrasound tests. The examinations and tests have been carried out at the Internal Noncontagious Disease Clinic at the Veterinary Faculty of the Thracian University in Stara Zagora

  12. Strigolactone levels in dicot roots are determined by an ancestral symbiosis-regulated clade of the PHYTOENE SYNTHASE gene family

    NARCIS (Netherlands)

    Stauder, Ron; Welsch, Ralf; Camagna, Maurizio; Kohlen, Wouter; Balcke, Gerd U.; Tissier, Alain; Walter, Michael H.

    2018-01-01

    Strigolactones (SLs) are apocarotenoid phytohormones synthesized from carotenoid precursors. They are produced most abundantly in roots for exudation into the rhizosphere to cope with mineral nutrient starvation through support of root symbionts. Abscisic acid (ABA) is another apocarotenoid

  13. Confirmation and quantification of strigolactones, germination stimulants for root parasitic plants Striga and Orobanche, produced by cotton.

    Science.gov (United States)

    Sato, Daisuke; Awad, Ayman A; Takeuchi, Yasutomo; Yoneyama, Koichi

    2005-01-01

    The germination stimulants for root parasitic plants Striga and Orobanche produced by cotton (Gossypium hirsutum L.) were examined in detail. Seeds of cotton were germinated and grown on glass wool wetted with sterile distilled water in sterile filter units. The root exudate was collected daily and extracted with ethyl acetate. Each of these ethyl acetate extracts was analyzed directly by high-performance liquid chromatography linked with tandem mass spectrometry (LC/MS/MS). The results demonstrate that cotton roots exuded strigol and strigyl acetate, but no other known strigolactones such as orobanchol and alectrol. The production of strigol was detected even in the root exudate collected during the first 24 h of incubation and reached a maximum 5-7 days later. The average exudation of strigol and strigyl acetate during the incubation period was ca. 15 and 2 pg/plant/day, respectively, indicating that strigol mainly contributed to germination stimulation by the cotton root exudate.

  14. Root dynamics in an artificially constructed regenerating longleaf pine ecosystem are affected by atmospheric CO(2) enrichment.

    Science.gov (United States)

    Pritchard, S G.; Davis, M A.; Mitchell, R J.; Prior, S A.; Boykin, D L.; Rogers, H H.; Runion, G B.

    2001-08-01

    Differential responses to elevated atmospheric CO(2) concentration exhibited by different plant functional types may alter competition for above- and belowground resources in a higher CO(2) world. Because C allocation to roots is often favored over C allocation to shoots in plants grown with CO(2) enrichment, belowground function of forest ecosystems may change significantly. We established an outdoor facility to examine the effects of elevated CO(2) on root dynamics in artificially constructed communities of five early successional forest species: (1) a C(3) evergreen conifer (longleaf pine, Pinus palustris Mill.); (2) a C(4) monocotyledonous bunch grass (wiregrass, Aristida stricta Michx.); (3) a C(3) broadleaf tree (sand post oak, Quercus margaretta); (4) a C(3) perennial herbaceous legume (rattlebox, Crotalaria rotundifolia Walt. ex Gemel); and (5) an herbaceous C(3) dicotyledonous perennial (butterfly weed, Asclepias tuberosa L.). These species are common associates in early successional longleaf pine savannahs throughout the southeastern USA and represent species that differ in life-form, growth habit, physiology, and symbiotic relationships. A combination of minirhizotrons and soil coring was used to examine temporal and spatial rooting dynamics from October 1998 to October 1999. CO(2)-enriched plots exhibited 35% higher standing root crop length, 37% greater root length production per day, and 47% greater root length mortality per day. These variables, however, were enhanced by CO(2) enrichment only at the 10-30 cm depth. Relative root turnover (flux/standing crop) was unchanged by elevated CO(2). Sixteen months after planting, root biomass of pine was 62% higher in elevated compared to ambient CO(2) plots. Conversely, the combined biomass of rattlebox, wiregrass, and butterfly weed was 28% greater in ambient compared to high CO(2) plots. There was no difference in root biomass of oaks after 16 months of exposure to elevated CO(2). Using root and shoot

  15. Dynamic transcriptional profiling provides insights into tuberous root development in Rehmannia glutinosa

    Directory of Open Access Journals (Sweden)

    Peng eSun

    2015-06-01

    Full Text Available Rehmannia glutinosa, a herb of the Scrophulariaceae family, is widely cultivated in the Northern part of China. The tuberous root has well known medicinal properties; however, yield and quality are threatened by abiotic and biotic stresses. Understanding the molecular process of tuberous root development may help identify novel targets for its control. In the present study, we used Illumina sequencing and de novo assembly strategies to obtain a reference transcriptome that is relevant to tuberous root development. We then conducted RNA-seq quantification analysis to determine gene expression profiles of the adventitious root (AR, thickening adventitious root (TAR, and the developing tuberous root (DTR. Expression profiling identified a total of 6,974 differentially expressed unigenes during root developmental. Bioinformatics analysis and gene expression profiling revealed changes in phenylpropanoid biosynthesis, starch and sucrose metabolism, and plant hormone biosynthesis during root development. Moreover, we identified and allocated putative functions to the genes involved in tuberous root development, including genes related to major carbohydrate metabolism, hormone metabolism, and transcription regulation. The present study provides the initial description of gene expression profiles of AR, TAR, and DTR, which facilitates identification of genes of interest. Moreover, our work provides insights into the molecular mechanisms underlying tuberous root development and may assist in the design and development of improved breeding schemes for different R. glutinosa varieties through genetic manipulation.

  16. Facilitative root interactions in intercrops

    DEFF Research Database (Denmark)

    Hauggaard-Nielsen, H.; Jensen, E.S.

    2005-01-01

    of root architecture, exudation of growth stimulating substances, and biofumigation. Facilitative root interactions are most likely to be of importance in nutrient poor soils and in low-input agroecosystems due to critical interspecific competition for plant growth factors. However, studies from more...... nitrogen transfer between legumes and non-leguminous plants, exploitation of the soil via mycorrhizal fungi and soil-plant processes which alter the mobilisation of plant growth resources such as through exudation of amino acids, extra-cellular enzymes, acidification, competition-induced modification......Facilitation takes place when plants ameliorate the environment of their neighbours, and increase their growth and survival. Facilitation occurs in natural ecosystems as well as in agroecosystems. We discuss examples of facilitative root interactions in intercropped agroecosystems; including...

  17. Elevated atmospheric CO2 in a semi-natural grassland: Root dynamics, decomposition and soil C balances

    International Nuclear Information System (INIS)

    Sindhoej, Erik

    2001-01-01

    This thesis focuses on how elevated atmospheric CO 2 affects a semi-natural grassland, with emphasis on root growth, decomposition and the subsequent long-term effects on soil C balances. Parts of a semi-natural grassland in Central Sweden were enclosed in open-top chambers and exposed to ambient and elevated levels of CO 2 (+350 μmol mol -1 ) from 1995 to 2000, while chamberless rings were used for controls. Root dynamics were observed with minirhizotrons while root biomass and production were studied with soil cores and ingrowth cores. Roots collected from ingrowth cores were incubated under controlled conditions for 160 days to measure root decomposition rates. Treatment-induced differences in microclimate, C input and root decomposability were entered into the ICBM soil C balance model for 30-year projections of soil C balances for the three treatments. Elevated CO 2 chambers had higher biomass production both above and below ground compared to ambient, however the root response increased over the years while the shoot response decreased. Plants grown under elevated CO 2 had greater water-use efficiency compared to ambient, which was shown in higher soil moisture and greater biomass production during slightly dry years. Elevated CO 2 chambers showed higher root appearance rates in spring and higher disappearance rates during autumn and winter. Roots from plants grown under elevated CO 2 decomposed more rapidly. The decreased input and the drier conditions in the ambient chambers were projected to lead to a 1.7% decrease in soil C over 30 years. Under elevated CO 2 , however, the increased input compensated for the higher root decomposability and moister soil conditions and lead only to a projected 1.3% decrease in soil C. This work shows that six years of elevated CO 2 exposure had extensive effects on this semi-natural grassland. The CO 2 response of the grassland was dependent on weather conditions and production increased most when under slight water stress

  18. Lactic acid bacteria population dynamics during spontaneous fermentation of radish (Raphanus sativus L.) roots in brine.

    Science.gov (United States)

    Pardali, Eleni; Paramithiotis, Spiros; Papadelli, Marina; Mataragas, Marios; Drosinos, Eleftherios H

    2017-06-01

    The aim of the present study was to assess the microecosystem development and the dynamics of the lactic acid bacteria population during spontaneous fermentation of radish (Raphanus sativus L.) roots in brine at 20 and 30 °C. In both temperatures, lactic acid bacteria prevailed the fermentation; as a result, the pH value was reduced to ca. 3.6 and total titrable acidity increased to ca. 0.4% lactic acid. Enterococci population increased and formed a secondary microbiota while pseudomonads, Enterobacteriaceae and yeasts/molds populations were below enumeration limit already before the middle of fermentation. Pediococcus pentosaceus dominated during the first days, followed by Lactobacillus plantarum that prevailed the fermentation until the end. Lactobacillus brevis was also detected during the final days of fermentation. A succession at sub-species level was revealed by the combination of RAPD-PCR and rep-PCR analyses. Glucose and fructose were the main carbohydrates detected in brine and were metabolized into lactic acid, acetic acid and ethanol.

  19. Automated detection of exudates for diabetic retinopathy screening

    International Nuclear Information System (INIS)

    Fleming, Alan D; Philip, Sam; Goatman, Keith A; Williams, Graeme J; Olson, John A; Sharp, Peter F

    2007-01-01

    Automated image analysis is being widely sought to reduce the workload required for grading images resulting from diabetic retinopathy screening programmes. The recognition of exudates in retinal images is an important goal for automated analysis since these are one of the indicators that the disease has progressed to a stage requiring referral to an ophthalmologist. Candidate exudates were detected using a multi-scale morphological process. Based on local properties, the likelihoods of a candidate being a member of classes exudate, drusen or background were determined. This leads to a likelihood of the image containing exudates which can be thresholded to create a binary decision. Compared to a clinical reference standard, images containing exudates were detected with sensitivity 95.0% and specificity 84.6% in a test set of 13 219 images of which 300 contained exudates. Depending on requirements, this method could form part of an automated system to detect images showing either any diabetic retinopathy or referable diabetic retinopathy

  20. Automated detection of exudates for diabetic retinopathy screening

    Energy Technology Data Exchange (ETDEWEB)

    Fleming, Alan D [Biomedical Physics, University of Aberdeen, Aberdeen, AB25 2ZD (United Kingdom); Philip, Sam [Diabetes Retinal Screening Service, David Anderson Building, Foresterhill Road, Aberdeen, AB25 2ZP (United Kingdom); Goatman, Keith A [Biomedical Physics, University of Aberdeen, Aberdeen, AB25 2ZD (United Kingdom); Williams, Graeme J [Diabetes Retinal Screening Service, David Anderson Building, Foresterhill Road, Aberdeen, AB25 2ZP (United Kingdom); Olson, John A [Diabetes Retinal Screening Service, David Anderson Building, Foresterhill Road, Aberdeen, AB25 2ZP (United Kingdom); Sharp, Peter F [Biomedical Physics, University of Aberdeen, Aberdeen, AB25 2ZD (United Kingdom)

    2007-12-21

    Automated image analysis is being widely sought to reduce the workload required for grading images resulting from diabetic retinopathy screening programmes. The recognition of exudates in retinal images is an important goal for automated analysis since these are one of the indicators that the disease has progressed to a stage requiring referral to an ophthalmologist. Candidate exudates were detected using a multi-scale morphological process. Based on local properties, the likelihoods of a candidate being a member of classes exudate, drusen or background were determined. This leads to a likelihood of the image containing exudates which can be thresholded to create a binary decision. Compared to a clinical reference standard, images containing exudates were detected with sensitivity 95.0% and specificity 84.6% in a test set of 13 219 images of which 300 contained exudates. Depending on requirements, this method could form part of an automated system to detect images showing either any diabetic retinopathy or referable diabetic retinopathy.

  1. Automated detection of exudates for diabetic retinopathy screening

    Science.gov (United States)

    Fleming, Alan D.; Philip, Sam; Goatman, Keith A.; Williams, Graeme J.; Olson, John A.; Sharp, Peter F.

    2007-12-01

    Automated image analysis is being widely sought to reduce the workload required for grading images resulting from diabetic retinopathy screening programmes. The recognition of exudates in retinal images is an important goal for automated analysis since these are one of the indicators that the disease has progressed to a stage requiring referral to an ophthalmologist. Candidate exudates were detected using a multi-scale morphological process. Based on local properties, the likelihoods of a candidate being a member of classes exudate, drusen or background were determined. This leads to a likelihood of the image containing exudates which can be thresholded to create a binary decision. Compared to a clinical reference standard, images containing exudates were detected with sensitivity 95.0% and specificity 84.6% in a test set of 13 219 images of which 300 contained exudates. Depending on requirements, this method could form part of an automated system to detect images showing either any diabetic retinopathy or referable diabetic retinopathy.

  2. Ubiquitous water-soluble molecules in aquatic plant exudates determine specific insect attraction.

    Science.gov (United States)

    Sérandour, Julien; Reynaud, Stéphane; Willison, John; Patouraux, Joëlle; Gaude, Thierry; Ravanel, Patrick; Lempérière, Guy; Raveton, Muriel

    2008-10-08

    Plants produce semio-chemicals that directly influence insect attraction and/or repulsion. Generally, this attraction is closely associated with herbivory and has been studied mainly under atmospheric conditions. On the other hand, the relationship between aquatic plants and insects has been little studied. To determine whether the roots of aquatic macrophytes release attractive chemical mixtures into the water, we studied the behaviour of mosquito larvae using olfactory experiments with root exudates. After testing the attraction on Culex and Aedes mosquito larvae, we chose to work with Coquillettidia species, which have a complex behaviour in nature and need to be attached to plant roots in order to obtain oxygen. This relationship is non-destructive and can be described as commensal behaviour. Commonly found compounds seemed to be involved in insect attraction since root exudates from different plants were all attractive. Moreover, chemical analysis allowed us to identify a certain number of commonly found, highly water-soluble, low-molecular-weight compounds, several of which (glycerol, uracil, thymine, uridine, thymidine) were able to induce attraction when tested individually but at concentrations substantially higher than those found in nature. However, our principal findings demonstrated that these compounds appeared to act synergistically, since a mixture of these five compounds attracted larvae at natural concentrations (0.7 nM glycerol, insect relationships in aquatic eco-systems.

  3. Dynamics of plant nutrient uptake as affected by biopore-associated root growth in arable subsoil

    DEFF Research Database (Denmark)

    Han, Eusun; Kautz, Timo; Huang, Ning

    2017-01-01

    %) precrops, respectively. On average root diameter and root dry mass of following crops were greater by 11 and 15 % after chicory than tall fescue. At anthesis chicory-barley treatment accumulated 10 % more K in comparison to tall fescue-barley treatment. P uptake of canola was greater (7 %) after tall...... fescue compared with chicory at the stage of fruit development. Conclusions: Our results suggest that the subsoil heterogenization by altered soil biopores hold relevance for plant root growth and overall crop performance. However, the effects depended on biopore size classes, root characteristics...

  4. Reactive oxygen species dynamics in roots of salt sensitive and salt tolerant cultivars of rice.

    Science.gov (United States)

    Saini, Shivani; Kaur, Navdeep; Pati, Pratap Kumar

    2018-06-01

    Salinity stress is one of the major constraints for growth and survival of plants that affects rice productivity worldwide. Hence, in the present study, roots of two contrasting salinity sensitive cultivars, IR64 (IR64, salt sensitive) and Luna Suvarna (LS, salt tolerant) were compared with regard to the levels of reactive oxygen species (ROS) to derive clues for their differential salt stress adaptation mechanisms. In our investigation, the tolerant cultivar exhibited longer primary roots, more lateral roots, higher root number leading to increased root biomass, with respect to IR64. It was observed that LS roots maintained higher level of H 2 O 2 in comparison to IR64. The activities of various enzymes involved in enzymatic antioxidant defense mechanism (SOD, CAT, GPX, DHAR and MDHAR) were found to be greater in LS roots. Further, the higher transcript level accumulation of genes encoding ROS generating (RbohA, RbohD and RbohE) and scavenging enzymes (Fe-SOD, Chloroplastic Cu/Zn-SOD, CAT and DHAR) were noticed in the roots of tolerant cultivar, LS. Moreover, the content of other stress markers such as total protein and proline were also elevated in LS roots. While, the expression of proline biosynthesis gene (P5CS) and proline catabolism gene (PDH) was observed to be lower in LS. Copyright © 2018. Published by Elsevier Inc.

  5. Using Micro-Computed Tomography to Evaluate the Dynamics of Orthodontically Induced Root Resorption Repair in a Rat Model.

    Directory of Open Access Journals (Sweden)

    Xiaolin Xu

    Full Text Available To observe dynamic changes in root resorption repair, tooth movement relapse and alveolar bone microstructure following the application of orthodontic force.Forces of 20 g, 50 g or 100 g were delivered to the left maxillary first molars of fifteen 10-week-old rats for 14 days. Each rat was subjected to micro-computed tomography scanning at 0, 3, 7, 10, 14, 28 and 42 days after force removal. The root resorption crater volume, tooth movement relapse and alveolar bone microarchitecture were measured at each time point.From day 3 to day 14, the root resorption volume decreased significantly in each group. In the 20-g force group, the root resorption volume gradually stabilized after 14 days, whereas in the 50-g and 100-g force groups, it stabilized after 28 days. In all groups, tooth movement relapsed significantly from day 0 to day 14 and then remained stable. From day 3 to day 10, the 20-g group exhibited faster relapse than the 50-g and 100-g groups. In all groups, the structure model index and trabecular separation decreased slowly from day 0 to day 10 and eventually stabilized. Trabecular number increased slowly from day 0 to day 7 and then stabilized.The initial stage of root resorption repair did not change significantly and was followed by a dramatic repair period before stabilizing. The most serious tooth movement relapse occurred immediately after the appliance was removed, and then the tooth completely returned to the original position.

  6. A review on exudates detection methods for diabetic retinopathy.

    Science.gov (United States)

    Joshi, Shilpa; Karule, P T

    2018-01-01

    The presence of exudates on the retina is the most characteristic symptom of diabetic retinopathy. As exudates are among early clinical signs of DR, their detection would be an essential asset to the mass screening task and serve as an important step towards automatic grading and monitoring of the disease. Reliable identification and classification of exudates are of inherent interest in an automated diabetic retinopathy screening system. Here we review the numerous early studies that used for automatic exudates detection with the aim of providing decision support in addition to reducing the workload of an ophthalmologist. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  7. Stochastic soil water dynamics of phreatophyte vegetation with dimorphic root systems

    NARCIS (Netherlands)

    Vervoort, R.W.; Zee, van der S.E.A.T.M.

    2009-01-01

    As the direct uptake of deep groundwater by vegetation may be essential in semiarid regions, we incorporated this process in stochastic root zone water balance models. The direct water uptake by vegetation via deep tap roots is simulated using one additional empirical parameter. This is considered

  8. Fine Root Abundance and Dynamics of Stone Pine (Pinus cembra) at the Alpine Treeline Is Not Impaired by Self-shading.

    Science.gov (United States)

    Kubisch, Petra; Leuschner, Christoph; Coners, Heinz; Gruber, Andreas; Hertel, Dietrich

    2017-01-01

    Low temperatures are crucial for the formation of the alpine treeline worldwide. Since soil temperature in the shade of tree canopies is lower than in open sites, it was assumed that self-shading may impair the trees' root growth performance. While experiments with tree saplings demonstrate root growth impairment at soil temperatures below 5-7°C, field studies exploring the soil temperature - root growth relationship at the treeline are missing. We recorded soil temperature and fine root abundance and dynamics in shaded and sun-exposed areas under canopies of isolated Pinus cembra trees at the alpine treeline. In contrast to the mentioned assumption, we found more fine root biomass and higher fine root growth in colder than in warmer soil areas. Moreover, colder areas showed higher fine root turnover and thus lower root lifespan than warmer places. We conclude that P. cembra balances enhanced fine root mortality in cold soils with higher fine root activity and by maintaining higher fine root biomass, most likely as a response to shortage in soil resource supply. The results from our study highlight the importance of in situ measurements on mature trees to understand the fine root response and carbon allocation pattern to the thermal growth conditions at the alpine treeline.

  9. Glycolysis Is Dynamic and Relates Closely to Respiration Rate in Stored Sugarbeet Roots

    Directory of Open Access Journals (Sweden)

    Clarice A. Megguer

    2017-05-01

    Full Text Available Although respiration is the principal cause of the loss of sucrose in postharvest sugarbeet (Beta vulgaris L., the internal mechanisms that control root respiration rate are unknown. Available evidence, however, indicates that respiration rate is likely to be controlled by the availability of respiratory substrates, and glycolysis has a central role in generating these substrates. To determine glycolytic changes that occur in sugarbeet roots after harvest and to elucidate relationships between glycolysis and respiration, sugarbeet roots were stored for up to 60 days, during which activities of glycolytic enzymes and concentrations of glycolytic substrates, intermediates, cofactors, and products were determined. Respiration rate was also determined, and relationships between respiration rate and glycolytic enzymes and metabolites were evaluated. Glycolysis was highly variable during storage, with 10 of 14 glycolytic activities and 14 of 17 glycolytic metabolites significantly altered during storage. Changes in glycolytic enzyme activities and metabolites occurred throughout the 60 day storage period, but were greatest in the first 4 days after harvest. Positive relationships between changes in glycolytic enzyme activities and root respiration rate were abundant, with 10 of 14 enzyme activities elevated when root respiration was elevated and 9 glycolytic activities static during periods of unchanging respiration rate. Major roles for pyruvate kinase and phosphofructokinase in the regulation of postharvest sugarbeet root glycolysis were indicated based on changes in enzymatic activities and concentrations of their substrates and products. Additionally, a strong positive relationship between respiration rate and pyruvate kinase activity was found indicating that downstream TCA cycle enzymes were unlikely to regulate or restrict root respiration in a major way. Overall, these results establish that glycolysis is not static during sugarbeet root

  10. Degradation of Surfactants in Hydroponic Wheat Root Zones

    Science.gov (United States)

    Monje, Oscar; McCoy, Lashelle; Flanagan, Aisling

    Hygiene water recycling in recirculating hydroponic systems can be enhanced by plant roots by providing a substrate and root exudates for bacterial growth. However, reduced plant growth can occur during batch mode additions of high concentrations of surfactant. An analog hygiene water stream containing surfactants (Steol CS330, Mirataine CB) was added to a hydroponically-grown wheat plant root zone. The plants were grown at 700 mol mol-1 CO2, a photosynthetic photon flux of 300 mol m-2 s-1, and a planting density of 380 plants m-2. Volumetric oxygen mass transfer coefficients were determined using the fermentative/dynamic outgassing method to maintain adequate oxygen mass transfer rates in the root zone. This analysis suggested an optimal flow rate of the hydroponic solution of 5 L min-1. The hydroponic system was inoculated with biofilm from a bioreactor and rates of surfactant degradation were measured daily based on reduction in chemical oxygen demand (COD). The COD decreased from 400 to 100 mg L-1 after 2 days following batch addition of the analog hygiene water to the hydroponic system. Measurements of dissolved oxygen concentration and solution temperature suggest that the root zone was provided adequate aeration to meet both oxygen demands from plant and microbial respiration during the degradation of the surfactant. Results from this study show that hydroponic systems can be used to enhance rates of hygiene water processing.

  11. Dynamic QTL and epistasis analysis on seedling root traits in upland ...

    Indian Academy of Sciences (India)

    2014-04-21

    Apr 21, 2014 ... phenotypic values at the time t conditional on the pheno- typic values ...... root, which directly determines drought tolerance and yield potential of ..... Talents of the Ministry of Education (NCET-06-0106) to J. Hua. References.

  12. Norway spruce fine root dynamics and carbon input into soil in relation to environmental factors

    OpenAIRE

    Leppälammi-Kujansuu, Jaana

    2014-01-01

    Knowledge of the quantity of belowground litter carbon (C) input is scarce but highly valued in C budget calculations. Specifically, the turnover rate of fine roots is considered to be one of the most important parameters in the estimation of changes in soil C stock. In this thesis Norway spruce (Picea abies L. (Karst.)) fine root lifespan and litter production and their responses to nutrient availability and temperature were examined. Aboveground foliage and understory litter C inputs were a...

  13. Chemical composition of essential oil of exudates of Dryobalanops ...

    African Journals Online (AJOL)

    Purpose: To identify the chemical composition of essential oil from the exudates of Dryobalanops aromatica from Malaysia. Methods: Exudate was collected from D. aromatica and subjected to fractional distillation to obtain essential oil. Gas chromatography-mass spectrometry (GC-MS) was used to characterize the ...

  14. THE SYSTEMATIC AND EVOLUTIONARY SIGNIFICANCE OF EXUDATE FLAVONOIDS IN AEONIUM

    NARCIS (Netherlands)

    STEVENS, JF; HART, HT; WOLLENWEBER, E

    Leaf exudates of 32 species of Aeonium were examined for the presence of flavonoids. Thirty two flavonoids were detected in exudates of half of the species. The flavonoids were identified as methyl ethers of kaempferol, 6-hydroxykaempferol, quercetin, myricetin and scutellarein. The distribution of

  15. Recurrent Exudative Pleural Effusion with Flare up of Chronic ...

    African Journals Online (AJOL)

    We describe herein a young male patient who presented with exudative pleural effusion that appeared with flare up of chronic HBV infection and spontaneously recovered with the clinical and biochemical improvement of the hepatitis on two occasions five months apart. Other causes of hepatitis and exudative pleural ...

  16. Trickle-bed root culture bioreactor design and scale-up: growth, fluid-dynamics, and oxygen mass transfer.

    Science.gov (United States)

    Ramakrishnan, Divakar; Curtis, Wayne R

    2004-10-20

    Trickle-bed root culture reactors are shown to achieve tissue concentrations as high as 36 g DW/L (752 g FW/L) at a scale of 14 L. Root growth rate in a 1.6-L reactor configuration with improved operational conditions is shown to be indistinguishable from the laboratory-scale benchmark, the shaker flask (mu=0.33 day(-1)). These results demonstrate that trickle-bed reactor systems can sustain tissue concentrations, growth rates and volumetric biomass productivities substantially higher than other reported bioreactor configurations. Mass transfer and fluid dynamics are characterized in trickle-bed root reactors to identify appropriate operating conditions and scale-up criteria. Root tissue respiration goes through a minimum with increasing liquid flow, which is qualitatively consistent with traditional trickle-bed performance. However, liquid hold-up is much higher than traditional trickle-beds and alternative correlations based on liquid hold-up per unit tissue mass are required to account for large changes in biomass volume fraction. Bioreactor characterization is sufficient to carry out preliminary design calculations that indicate scale-up feasibility to at least 10,000 liters.

  17. Decomposition and nitrogen dynamics of 15N-labeled leaf, root, and twig litter in temperate coniferous forests

    Science.gov (United States)

    van Huysen, Tiff L.; Harmon, Mark E.; Perakis, Steven S.; Chen, Hua

    2013-01-01

    Litter nutrient dynamics contribute significantly to biogeochemical cycling in forest ecosystems. We examined how site environment and initial substrate quality influence decomposition and nitrogen (N) dynamics of multiple litter types. A 2.5-year decomposition study was installed in the Oregon Coast Range and West Cascades using 15N-labeled litter from Acer macrophyllum, Picea sitchensis, and Pseudotsuga menziesii. Mass loss for leaf litter was similar between the two sites, while root and twig litter exhibited greater mass loss in the Coast Range. Mass loss was greatest from leaves and roots, and species differences in mass loss were more prominent in the Coast Range. All litter types and species mineralized N early in the decomposition process; only A. macrophyllum leaves exhibited a net N immobilization phase. There were no site differences with respect to litter N dynamics despite differences in site N availability, and litter N mineralization patterns were species-specific. For multiple litter × species combinations, the difference between gross and net N mineralization was significant, and gross mineralization was 7–20 % greater than net mineralization. The mineralization results suggest that initial litter chemistry may be an important driver of litter N dynamics. Our study demonstrates that greater amounts of N are cycling through these systems than may be quantified by only measuring net mineralization and challenges current leaf-based biogeochemical theory regarding patterns of N immobilization and mineralization.

  18. Decomposition and nitrogen dynamics of (15)N-labeled leaf, root, and twig litter in temperate coniferous forests.

    Science.gov (United States)

    van Huysen, Tiff L; Harmon, Mark E; Perakis, Steven S; Chen, Hua

    2013-12-01

    Litter nutrient dynamics contribute significantly to biogeochemical cycling in forest ecosystems. We examined how site environment and initial substrate quality influence decomposition and nitrogen (N) dynamics of multiple litter types. A 2.5-year decomposition study was installed in the Oregon Coast Range and West Cascades using (15)N-labeled litter from Acer macrophyllum, Picea sitchensis, and Pseudotsuga menziesii. Mass loss for leaf litter was similar between the two sites, while root and twig litter exhibited greater mass loss in the Coast Range. Mass loss was greatest from leaves and roots, and species differences in mass loss were more prominent in the Coast Range. All litter types and species mineralized N early in the decomposition process; only A. macrophyllum leaves exhibited a net N immobilization phase. There were no site differences with respect to litter N dynamics despite differences in site N availability, and litter N mineralization patterns were species-specific. For multiple litter × species combinations, the difference between gross and net N mineralization was significant, and gross mineralization was 7-20 % greater than net mineralization. The mineralization results suggest that initial litter chemistry may be an important driver of litter N dynamics. Our study demonstrates that greater amounts of N are cycling through these systems than may be quantified by only measuring net mineralization and challenges current leaf-based biogeochemical theory regarding patterns of N immobilization and mineralization.

  19. Exudation of organic acids by Lupinus albus and Lupinus angustifolius as affected by phosphorus supply

    Science.gov (United States)

    Hentschel, Werner; Wiche, Oliver

    2016-04-01

    In phytomining and phytoremediation research mixed cultures of bioenergy crops with legumes hold promise to enhance availability of trace metals and metalloids in the soil plant system. This is due to the ability of certain legumes to mobilize trace elements during acquisition of nutrients making these elements available for co-cultured species. The legumes achieve this element mobilization by exudating carboxylates and enzymes as well as by lowering the pH value in the rhizosphere. The aim of our research was to determine characteristics and differences in the exudation of Lupinus albus and Lupinus angustifolius regarding to quantitative as to qualitative aspects. Especially the affection by phosphorus (P) supply was a point of interest. Thus we conducted laboratory batch experiments, wherein the plants were grown over four weeks under controlled light, moisture and nutritional conditions on sand as substrate. Half of the plants were supplied with 12 mg P per kg substrate, the other half were cultivated under a total lack of P. After cultivation the plants were transferred from the cultivation substrate into a 0,05 mmolṡL-1 CaCl2 solution. After two hours the plants were removed, moist and dry mass off shoots and roots were measured together with the root length (Tennants' method). Concentrations of exudated carboxylates in the CaCl2 solution were determined via IC (column: Metrosept OrganicAcids, eluent 0.5 molṡL-1 H2SO4 + 15% acetone, pH=3; 0.5 mLṡmin-1). As a result four different organic acids were identified (citric acid, fumaric acid, tartaric acid, malic acid) in concentration ranges of 0.15 mgṡL-1 (fumaric acid) to 9.21 mgṡL-1 (citric acid). Lupinus angustifolius showed a higher exudation rate (in nmol per cm root length per hour) than Lupinus albus in the presence of phosphorus (e.g. regarding citric acid: 1.99 vs 0.64 nmolṡ(gṡh)-1). However, as the root complexity and length of L. albus were far higher than of L. angustifolius, the total

  20. Microbial processes associated with roots of bulbous rush coated with iron plaques

    Energy Technology Data Exchange (ETDEWEB)

    Kusel, K.; Chabbi, A.; Trinkwalter, T. [University of Bayreuth, Bayreuth (Germany). BITOEK

    2003-11-01

    The objectives of this work were to enumerate the microbes involved in the turnover of iron and organic root exudates in the rhizoplane, to investigate the effect of oxygen and pH on the utilization of these exudates by the rhizobacteria, and to study the ability of the root-colonizing microbiota to reduce sulfate. Enumeration studies done at pH 3 demonstrated that 10{sup 6} Fe(III) reducers and 10{sup 7} Fe(II) oxidizers g (fresh wt root){sup -1} were associated with Juncus roots. When roots were incubated in goethite-containing medium without and with supplemental glucose, Fe(II) was formed at rates approximating 1.1 mmol g (fresh wt root) {sup -1} d{sup -1} and 3.6 mmol g (fresh wt root){sup -1} d{sup -1} under anoxic conditions, respectively. These results suggest that a rapid microbially mediated cycling of iron occurs in the rhizosphere of Juncus roots under changing redox conditions. Most-probable-number estimates of aerobes and anaerobes capable of consuming root exudates at pH 3 were similar in the rhizosphere sediment and in Juncus roots, but numbers of aerobes were significantly higher than those of anaerobes. At pH 3, supplemental organic exudates were primarily subject to aerobic oxidation to CO{sub 2} and not subject to fermentation. However, at pH 4.5, root exudates were also rapidly utilized under anoxic conditions. Root-associated sulfate reduction was not observed at pH 3 to 4.5 but was observed at pH 4.9. The pH increased during all root-incubation studies both under oxic and anoxic conditions. Thus, as result of the microbial turnover of organic root exudates, pH and CO{sub 2} levels might be elevated at the root surface and favor Juncus plants to colonize acidic habitats.

  1. Nitrogen fertilization and root growth dynamics of durum wheat for a sustainable production

    Directory of Open Access Journals (Sweden)

    Donato De Giorgio

    2012-07-01

    Full Text Available In an area of the Apulian Tavoliere (southern Italy, the effects of three levels of nitrogen fertilization (0, 50 and 100 kg N ha–1 on root development, growth analysis and yield parameters of durum wheat were evaluated. The research was conducted over a four-year period (1994-97. The non-destructive mini-rhizotron method was used to study the root system at stem extension and at the beginning of heading and ripening stages. At the end of tillering and at boot and flowering stages, samples of wheat biomass were taken and subjected to growth analysis. Yield data and the main biometric parameters were collected at harvest time. The doses of nitrogen (N fertilizer 50 and 100 kg N ha–1 had a greater effect on root development in the 20-30 cm soil layer and on epigeal biomass than the control test (N0 without nitrogen fertilization. In the test (N0 the growth of root and epigeal biomass was slower during the first vegetative phases, however, afterwards both of them recovered and the root system was mainly developed in the 30-40 cm soil layer. A better development of root system in deeper soil layers, without nitrogen supply, has allowed the plant to overcome more easily the water-deficit and thermal stresses during the ripening stage. The results of this research have shown that the production of grain with 50 kg ha–1 of N is similar to those of 100 kg ha–1 of N doses and higher than the test without nitrogen fertilization. In this kind of environment can be recommended a nitrogen dose of 50 kg ha–1 for obtaining an increase in grain production with low costs and reduced agricultural sources of pollution.

  2. Modeling of Soil Water and Salt Dynamics and Its Effects on Root Water Uptake in Heihe Arid Wetland, Gansu, China

    Directory of Open Access Journals (Sweden)

    Huijie Li

    2015-05-01

    Full Text Available In the Heihe River basin, China, increased salinity and water shortages present serious threats to the sustainability of arid wetlands. It is critical to understand the interactions between soil water and salts (from saline shallow groundwater and the river and their effects on plant growth under the influence of shallow groundwater and irrigation. In this study, the Hydrus-1D model was used in an arid wetland of the Middle Heihe River to investigate the effects of the dynamics of soil water, soil salinization, and depth to water table (DWT as well as groundwater salinity on Chinese tamarisk root water uptake. The modeled soil water and electrical conductivity of soil solution (ECsw are in good agreement with the observations, as indicated by RMSE values (0.031 and 0.046 cm3·cm−3 for soil water content, 0.037 and 0.035 dS·m−1 for ECsw, during the model calibration and validation periods, respectively. The calibrated model was used in scenario analyses considering different DWTs, salinity levels and the introduction of preseason irrigation. The results showed that (I Chinese tamarisk root distribution was greatly affected by soil water and salt distribution in the soil profile, with about 73.8% of the roots being distributed in the 20–60 cm layer; (II root water uptake accounted for 91.0% of the potential maximal value when water stress was considered, and for 41.6% when both water and salt stress were considered; (III root water uptake was very sensitive to fluctuations of the water table, and was greatly reduced when the DWT was either dropped or raised 60% of the 2012 reference depth; (IV arid wetland vegetation exhibited a high level of groundwater dependence even though shallow groundwater resulted in increased soil salinization and (V preseason irrigation could effectively increase root water uptake by leaching salts from the root zone. We concluded that a suitable water table and groundwater salinity coupled with proper irrigation

  3. Low pH, Aluminum, and Phosphorus Coordinately Regulate Malate Exudation through GmALMT1 to Improve Soybean Adaptation to Acid Soils1[W][OA

    Science.gov (United States)

    Liang, Cuiyue; Piñeros, Miguel A.; Tian, Jiang; Yao, Zhufang; Sun, Lili; Liu, Jiping; Shaff, Jon; Coluccio, Alison; Kochian, Leon V.; Liao, Hong

    2013-01-01

    Low pH, aluminum (Al) toxicity, and low phosphorus (P) often coexist and are heterogeneously distributed in acid soils. To date, the underlying mechanisms of crop adaptation to these multiple factors on acid soils remain poorly understood. In this study, we found that P addition to acid soils could stimulate Al tolerance, especially for the P-efficient genotype HN89. Subsequent hydroponic studies demonstrated that solution pH, Al, and P levels coordinately altered soybean (Glycine max) root growth and malate exudation. Interestingly, HN89 released more malate under conditions mimicking acid soils (low pH, +P, and +Al), suggesting that root malate exudation might be critical for soybean adaptation to both Al toxicity and P deficiency on acid soils. GmALMT1, a soybean malate transporter gene, was cloned from the Al-treated root tips of HN89. Like root malate exudation, GmALMT1 expression was also pH dependent, being suppressed by low pH but enhanced by Al plus P addition in roots of HN89. Quantitative real-time PCR, transient expression of a GmALMT1-yellow fluorescent protein chimera in Arabidopsis protoplasts, and electrophysiological analysis of Xenopus laevis oocytes expressing GmALMT1 demonstrated that GmALMT1 encodes a root cell plasma membrane transporter that mediates malate efflux in an extracellular pH-dependent and Al-independent manner. Overexpression of GmALMT1 in transgenic Arabidopsis, as well as overexpression and knockdown of GmALMT1 in transgenic soybean hairy roots, indicated that GmALMT1-mediated root malate efflux does underlie soybean Al tolerance. Taken together, our results suggest that malate exudation is an important component of soybean adaptation to acid soils and is coordinately regulated by three factors, pH, Al, and P, through the regulation of GmALMT1 expression and GmALMT1 function. PMID:23341359

  4. Low pH, aluminum, and phosphorus coordinately regulate malate exudation through GmALMT1 to improve soybean adaptation to acid soils.

    Science.gov (United States)

    Liang, Cuiyue; Piñeros, Miguel A; Tian, Jiang; Yao, Zhufang; Sun, Lili; Liu, Jiping; Shaff, Jon; Coluccio, Alison; Kochian, Leon V; Liao, Hong

    2013-03-01

    Low pH, aluminum (Al) toxicity, and low phosphorus (P) often coexist and are heterogeneously distributed in acid soils. To date, the underlying mechanisms of crop adaptation to these multiple factors on acid soils remain poorly understood. In this study, we found that P addition to acid soils could stimulate Al tolerance, especially for the P-efficient genotype HN89. Subsequent hydroponic studies demonstrated that solution pH, Al, and P levels coordinately altered soybean (Glycine max) root growth and malate exudation. Interestingly, HN89 released more malate under conditions mimicking acid soils (low pH, +P, and +Al), suggesting that root malate exudation might be critical for soybean adaptation to both Al toxicity and P deficiency on acid soils. GmALMT1, a soybean malate transporter gene, was cloned from the Al-treated root tips of HN89. Like root malate exudation, GmALMT1 expression was also pH dependent, being suppressed by low pH but enhanced by Al plus P addition in roots of HN89. Quantitative real-time PCR, transient expression of a GmALMT1-yellow fluorescent protein chimera in Arabidopsis protoplasts, and electrophysiological analysis of Xenopus laevis oocytes expressing GmALMT1 demonstrated that GmALMT1 encodes a root cell plasma membrane transporter that mediates malate efflux in an extracellular pH-dependent and Al-independent manner. Overexpression of GmALMT1 in transgenic Arabidopsis, as well as overexpression and knockdown of GmALMT1 in transgenic soybean hairy roots, indicated that GmALMT1-mediated root malate efflux does underlie soybean Al tolerance. Taken together, our results suggest that malate exudation is an important component of soybean adaptation to acid soils and is coordinately regulated by three factors, pH, Al, and P, through the regulation of GmALMT1 expression and GmALMT1 function.

  5. Dual permeability soil water dynamics and water uptake by roots in irrigated potato fields

    DEFF Research Database (Denmark)

    Dolezal, Frantisek; Zumr, David; Vacek, Josef

    2007-01-01

    Water movement and uptake by roots in a drip-irrigated potato field was studied by combining field experiments, outputs of numerical simulations and summary results of an EU project (www.fertorganic.org). Detailed measurements of soil suction and weather conditions in the Bohemo-Moravian highland...

  6. Drought and host selection influence microbial community dynamics in the grass root microbiome

    Science.gov (United States)

    Through 16S rRNA gene profiling across two distinct watering regimes and two developmental time points, we demonstrate that there is a strong correlation between host phylogenetic distance and the microbiome dissimilarity within root tissues, and that drought weakens this correlation by inducing con...

  7. Proline accumulation, ions dynamics and sodium root-shoot partition and compartmentation

    Directory of Open Access Journals (Sweden)

    Jesus Emanuel eBojorquez Quintal

    2014-11-01

    Full Text Available Despite its economic relevance, little is known about salt tolerance mechanisms in pepper plants. To address this question, we compared differences in responses to NaCl in two Capsicum chinense varieties: Rex (tolerant and Chichen-Itza (sensitive. Under salt stress (150 mM NaCl over 7 days roots of Rex variety accumulated 50 times more compatible solutes such as proline compared to Chichen-Itza. Mineral analysis indicated that Na+ is restricted to roots by preventing its transport to leaves. Fluorescence analysis suggested an efficient Na+ compartmentalization in vacuole-like structures and in small intracellular compartments in roots of Rex variety. At the same time, Na+ in Chichen-Itza plants was compartmentalized in the apoplast, suggesting substantial Na+ extrusion. Rex variety was found to retain more K+ in its roots under salt stress according to a mineral analysis and microelectrode ion flux estimation (MIFE. Vanadate-sensitive H+ efflux was higher in Chichen-Itza variety plants, suggesting a higher activity of the plasma membrane H+-ATPase, which fuels the extrusion of Na+, and, possibly, also the re-uptake of K+. Our results suggest a combination of stress tolerance mechanisms, in order to alleviate the salt-induced injury. Furthermore, Na+ extrusion to apoplast does not appear to be an efficient strategy for salt tolerance in pepper plants.

  8. LMWOA (low molecular weight organic acid) exudation by salt marsh plants: Natural variation and response to Cu contamination

    Science.gov (United States)

    Mucha, Ana P.; Almeida, C. Marisa R.; Bordalo, Adriano A.; Vasconcelos, M. Teresa S. D.

    2010-06-01

    This work aimed to evaluate, in vitro, the capability of roots of two salt marsh plants to release low molecular weight organic acids (LMWOAs) and to ascertain whether Cu contamination would stimulate or not organic acids exudation. The sea rush Juncus maritimus and the sea-club rush Scirpus maritimus, both from the lower Douro river estuary (NW Portugal), were used. Plants were collected seasonally, four times a year in 2004, during low tide. After sampling, plant roots were washed for removal of adherent particles and immersed for 2 h in a solution that matched salinity (3) and pH (7.5) of the pore water from the same location to obtain plant exudates. In one of the seasons, similar experiments were carried out but spiking the solution with different amounts of Cu in order to embrace the range between 0 and 1600 nM. In the final solutions as well as in sediment pore water LMWOAs were determined by high performance liquid chromatography. Plants were able to release, in a short period of time, relatively high amounts of LMWOAs (oxalate, citrate, malate, malonate, and succinate). In the sediment pore water oxalate, succinate and acetate were also detected. Therefore, plant roots probably contributed to the presence of some of these organic compounds in pore water. Exudation differed between the plant species and also showed some seasonally variation, particularly for S. maritimus. The release of oxalate by J. maritimus increased with Cu increase in the media. However, exudation of the other LMWOAs did not seem to be stimulated by Cu contamination in the media. This fact is compatible with the existence of alternative internal mechanisms for Cu detoxification, as denoted by the fact that in media contaminated with Cu both plant species accumulated relatively high amounts (29-83%) of the initially dissolved Cu. This study expands our knowledge on the contribution of globally dominant salt marsh plants to the release of LMWOAs into the environment.

  9. Fine root dynamics for forests on contrasting soils in the Colombian Amazon

    Directory of Open Access Journals (Sweden)

    E. M. Jiménez

    2009-12-01

    Full Text Available It has been hypothesized that as soil fertility increases, the amount of carbon allocated to below-ground production (fine roots should decrease. To evaluate this hypothesis, we measured the standing crop fine root mass and the production of fine roots (<2 mm by two methods: (1 ingrowth cores and, (2 sequential soil coring, during 2.2 years in two lowland forests growing on different soils types in the Colombian Amazon. Differences of soil resources were defined by the type and physical and chemical properties of soil: a forest on clay loam soil (Endostagnic Plinthosol at the Amacayacu National Natural Park and, the other on white sand (Ortseinc Podzol at the Zafire Biological Station, located in the Forest Reservation of the Calderón River. We found that the standing crop fine root mass and the production was significantly different between soil depths (0–10 and 10–20 cm and also between forests. The loamy sand forest allocated more carbon to fine roots than the clay loam forest with the production in loamy sand forest twice (mean±standard error=2.98±0.36 and 3.33±0.69 Mg C ha−1 yr−1, method 1 and 2, respectively as much as for the more fertile loamy soil forest (1.51±0.14, method 1, and from 1.03±0.31 to 1.36±0.23 Mg C ha−1 yr−1, method 2. Similarly, the average of standing crop fine root mass was higher in the white-sands forest (10.94±0.33 Mg C ha−1 as compared to the forest on the more fertile soil (from 3.04±0.15 to 3.64±0.18 Mg C ha−1. The standing crop fine root mass also showed a temporal pattern related to rainfall, with the production of fine roots decreasing substantially in the dry period of the year 2005. These results suggest that soil resources may play an important role in patterns of carbon allocation to the production of fine roots in these forests as the proportion of carbon allocated to above- and below-ground organs is different

  10. Reduced germination of Orobanche cumana seeds in the presence of Arbuscular Mycorrhizal fungi or their exudates.

    Directory of Open Access Journals (Sweden)

    Johann Louarn

    Full Text Available Broomrapes (Orobanche and Phelipanche spp are parasitic plants responsible for important crop losses, and efficient procedures to control these pests are scarce. Biological control is one of the possible strategies to tackle these pests. Arbuscular Mycorrhizal (AM fungi are widespread soil microorganisms that live symbiotically with the roots of most plant species, and they have already been tested on sorghum for their ability to reduce infestation by witchweeds, another kind of parasitic plants. In this work AM fungi were evaluated as potential biocontrol agents against Orobanche cumana, a broomrape species that specifically attacks sunflower. When inoculated simultaneously with O. cumana seeds, AM fungi could offer a moderate level of protection against the broomrape. Interestingly, this protection did not only rely on a reduced production of parasitic seed germination stimulants, as was proposed in previous studies. Rather, mycorrhizal root exudates had a negative impact on the germination of O. cumana induced by germination stimulants. A similar effect could be obtained with AM spore exudates, establishing the fungal origin of at least part of the active compounds. Together, our results demonstrate that AM fungi themselves can lead to a reduced rate of parasitic seed germination, in addition to possible effects mediated by the mycorrhizal plant. Combined with the other benefits of AM symbiosis, these effects make AM fungi an attractive option for biological control of O. cumana.

  11. Reduced germination of Orobanche cumana seeds in the presence of Arbuscular Mycorrhizal fungi or their exudates.

    Science.gov (United States)

    Louarn, Johann; Carbonne, Francis; Delavault, Philippe; Bécard, Guillaume; Rochange, Soizic

    2012-01-01

    Broomrapes (Orobanche and Phelipanche spp) are parasitic plants responsible for important crop losses, and efficient procedures to control these pests are scarce. Biological control is one of the possible strategies to tackle these pests. Arbuscular Mycorrhizal (AM) fungi are widespread soil microorganisms that live symbiotically with the roots of most plant species, and they have already been tested on sorghum for their ability to reduce infestation by witchweeds, another kind of parasitic plants. In this work AM fungi were evaluated as potential biocontrol agents against Orobanche cumana, a broomrape species that specifically attacks sunflower. When inoculated simultaneously with O. cumana seeds, AM fungi could offer a moderate level of protection against the broomrape. Interestingly, this protection did not only rely on a reduced production of parasitic seed germination stimulants, as was proposed in previous studies. Rather, mycorrhizal root exudates had a negative impact on the germination of O. cumana induced by germination stimulants. A similar effect could be obtained with AM spore exudates, establishing the fungal origin of at least part of the active compounds. Together, our results demonstrate that AM fungi themselves can lead to a reduced rate of parasitic seed germination, in addition to possible effects mediated by the mycorrhizal plant. Combined with the other benefits of AM symbiosis, these effects make AM fungi an attractive option for biological control of O. cumana.

  12. Nitrate Protects Cucumber Plants Against Fusarium oxysporum by Regulating Citrate Exudation.

    Science.gov (United States)

    Wang, Min; Sun, Yuming; Gu, Zechen; Wang, Ruirui; Sun, Guomei; Zhu, Chen; Guo, Shiwei; Shen, Qirong

    2016-09-01

    Fusarium wilt causes severe yield losses in cash crops. Nitrogen plays a critical role in the management of plant disease; however, the regulating mechanism is poorly understood. Using biochemical, physiological, bioinformatic and transcriptome approaches, we analyzed how nitrogen forms regulate the interactions between cucumber plants and Fusarium oxysporum f. sp. cucumerinum (FOC). Nitrate significantly suppressed Fusarium wilt compared with ammonium in both pot and hydroponic experiments. Fewer FOC colonized the roots and stems under nitrate compared with ammonium supply. Cucumber grown with nitrate accumulated less fusaric acid (FA) after FOC infection and exhibited increased tolerance to chemical FA by decreasing FA absorption and transportation in shoots. A lower citrate concentration was observed in nitrate-grown cucumbers, which was associated with lower MATE (multidrug and toxin compound extrusion) family gene and citrate synthase (CS) gene expression, as well as lower CS activity. Citrate enhanced FOC spore germination and infection, and increased disease incidence and the FOC population in ammonium-treated plants. Our study provides evidence that nitrate protects cucumber plants against F. oxysporum by decreasing root citrate exudation and FOC infection. Citrate exudation is essential for regulating disease development of Fusarium wilt in cucumber plants. © The Author 2016. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  13. Tumor Necrosis Factor-Alpha in Peripical Tissue Exudates of Teeth with Apical Periodontitis

    Directory of Open Access Journals (Sweden)

    Sonja Pezelj-Ribaric

    2007-01-01

    Full Text Available Aim. The aim of this study was to determine tumor necrosis factor-alpha (TNF-α levels in periapical exudates and to evaluate their relationship with radiological findings. Methodology. Periapical exudates were collected from root canals of 60 single-rooted teeth using absorbent paper points. TNF-α levels were determined by enzyme-linked immunosorbent assays. The samples were divided into three groups according to the periapical radiolucent area. Results. Nonparametric Kruskal-Wallis test revealed significant differences between TNF-α concentrations in control group (40, 57±28, 15 pg/mL and group with larger radiolucent areas (2365, 79±582, 95 pg/mL, as well as between control and canals with small radiolucent areas (507, 66±278, 97 (P<.05. Conclusions. The levels of TNF-α increase significantly in teeth with periapical pathosis, from smaller to bigger lesions. This research and its results have shown that objective analysis of the TNF-α levels enables establishment of a relationship between different concentrations of TNF-α and different radiological changes.

  14. A dynamic genetic-hormonal regulatory network model explains multiple cellular behaviors of the root apical meristem of Arabidopsis thaliana.

    Science.gov (United States)

    García-Gómez, Mónica L; Azpeitia, Eugenio; Álvarez-Buylla, Elena R

    2017-04-01

    The study of the concerted action of hormones and transcription factors is fundamental to understand cell differentiation and pattern formation during organ development. The root apical meristem of Arabidopsis thaliana is a useful model to address this. It has a stem cell niche near its tip conformed of a quiescent organizer and stem or initial cells around it, then a proliferation domain followed by a transition domain, where cells diminish division rate before transiting to the elongation zone; here, cells grow anisotropically prior to their final differentiation towards the plant base. A minimal model of the gene regulatory network that underlies cell-fate specification and patterning at the root stem cell niche was proposed before. In this study, we update and couple such network with both the auxin and cytokinin hormone signaling pathways to address how they collectively give rise to attractors that correspond to the genetic and hormonal activity profiles that are characteristic of different cell types along A. thaliana root apical meristem. We used a Boolean model of the genetic-hormonal regulatory network to integrate known and predicted regulatory interactions into alternative models. Our analyses show that, after adding some putative missing interactions, the model includes the necessary and sufficient components and regulatory interactions to recover attractors characteristic of the root cell types, including the auxin and cytokinin activity profiles that correlate with different cellular behaviors along the root apical meristem. Furthermore, the model predicts the existence of activity configurations that could correspond to the transition domain. The model also provides a possible explanation for apparently paradoxical cellular behaviors in the root meristem. For example, how auxin may induce and at the same time inhibit WOX5 expression. According to the model proposed here the hormonal regulation of WOX5 might depend on the cell type. Our results

  15. A dynamic genetic-hormonal regulatory network model explains multiple cellular behaviors of the root apical meristem of Arabidopsis thaliana.

    Directory of Open Access Journals (Sweden)

    Mónica L García-Gómez

    2017-04-01

    Full Text Available The study of the concerted action of hormones and transcription factors is fundamental to understand cell differentiation and pattern formation during organ development. The root apical meristem of Arabidopsis thaliana is a useful model to address this. It has a stem cell niche near its tip conformed of a quiescent organizer and stem or initial cells around it, then a proliferation domain followed by a transition domain, where cells diminish division rate before transiting to the elongation zone; here, cells grow anisotropically prior to their final differentiation towards the plant base. A minimal model of the gene regulatory network that underlies cell-fate specification and patterning at the root stem cell niche was proposed before. In this study, we update and couple such network with both the auxin and cytokinin hormone signaling pathways to address how they collectively give rise to attractors that correspond to the genetic and hormonal activity profiles that are characteristic of different cell types along A. thaliana root apical meristem. We used a Boolean model of the genetic-hormonal regulatory network to integrate known and predicted regulatory interactions into alternative models. Our analyses show that, after adding some putative missing interactions, the model includes the necessary and sufficient components and regulatory interactions to recover attractors characteristic of the root cell types, including the auxin and cytokinin activity profiles that correlate with different cellular behaviors along the root apical meristem. Furthermore, the model predicts the existence of activity configurations that could correspond to the transition domain. The model also provides a possible explanation for apparently paradoxical cellular behaviors in the root meristem. For example, how auxin may induce and at the same time inhibit WOX5 expression. According to the model proposed here the hormonal regulation of WOX5 might depend on the cell

  16. High-resolution quantification of root dynamics in split-nutrient rhizoslides reveals rapid and strong proliferation of maize roots in response to local high nitrogen.

    Science.gov (United States)

    in 't Zandt, Dina; Le Marié, Chantal; Kirchgessner, Norbert; Visser, Eric J W; Hund, Andreas

    2015-09-01

    The plant's root system is highly plastic, and can respond to environmental stimuli such as high nitrogen (N) in patches. A root may respond to an N patch by selective placement of new lateral roots, and therewith increases root N uptake. This may be a desirable trait in breeding programmes, since it decreases NO3(-) leaching and N2O emission. Roots of maize (Zea mays L.) were grown without N in split-nutrient rhizoslides. One side of the slides was exposed to high N after 15 d of root development, and root elongation was measured for another 15 d, described in a time course model and parameterized. The elongation rates of crown axile roots on the N-treated side of the plant followed a logistic increase to a maximum of 5.3cm d(-1); 95% of the maximum were reached within 4 d. At the same time, on the untreated side, axile root elongation dropped linearly to 1.2cm d(-1) within 6.4 d and stayed constant thereafter. Twice as many lateral roots were formed on the crown axis on the N side compared to the untreated side. Most strikingly, the elongation rates of laterals of the N side increased linearly with most of the roots reaching an asymptote ~8 d after start of the N treatment. By contrast, laterals on the side without N did not show any detectable elongation beyond the first day after their emergence. We conclude that split-nutrient rhizoslides have great potential to improve our knowledge about nitrogen responsiveness and selection for contrasting genotypes. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  17. The Effects of Dynamic Root Distribution on Land–Atmosphere Carbon and Water Fluxes in the Community Earth System Model (CESM1.2.0

    Directory of Open Access Journals (Sweden)

    Yuanyuan Wang

    2018-03-01

    Full Text Available Roots are responsible for the uptake of water and nutrients by plants, and they have the plasticity to respond dynamically to different environmental conditions. However, currently, most climate models only prescribe rooting profiles as a function of the vegetation type of the land component, with no consideration of the surroundings. In this study, a dynamic rooting scheme describing root growth as a compromise between water and nitrogen availability in the subsurface was incorporated into the Community Earth System Model 1.2.0 (CESM1.2.0. The dynamic rooting scheme was incorporated to investigate the effects of land–atmosphere carbon and water fluxes, and their subsequent influences on climate. The modeling results of global land–atmosphere coupling simulations from 1982 to 2005 show that the dynamic rooting scheme can improve gross primary production (GPP and evapotranspiration (ET in most tropical regions, and in some high-latitude regions with lower mean biases (MBEs and root mean square errors (RMSEs. Obvious differences in 2-m air temperature were found in low-latitude areas, with decreases of up to 2 °C. Under the influence of local land-surface feedback and large-scale moisture advection, total precipitation in the northeastern area of the Amazon and the west coast of Africa increased by 200 mm year−1, and that of South America, central Africa, and Indonesia increased by 50 to 100 mm year−1. Overall, the model incorporating the dynamic rooting scheme may reveal cooling and humidifying effects, especially for tropical regions.

  18. Do microbial exudates control EH electrode measurements?

    Science.gov (United States)

    Markelova, E.; Parsons, C. T.; Smeaton, C. M.; Van Cappellen, P.

    2017-12-01

    Redox electrodes are widely used as simple, inexpensive monitoring devices to rapidly measure redox potentials (EH) of waterlogged soils, sediments, and aquifers. While a variety of physicochemical and biogeochemical factors have been involved to explain measured EH values, the role of microorganisms remains comparatively understudied and uncertain. Besides catalyzing many inorganic redox reactions (e.g., nitrate reduction), microorganisms produce a variety of redox-active organic compounds (e.g., NAD+/NADH, GSSG/2GSH, FAD/FADH2), which can be released into the surrounding environment via active secretion, passive diffusion, or cell lysis. To isolate different microbial effects on EH measurements, we performed batch experiments using S. oneidensis MR-I as a model heterotrophic microorganism and flavins as example microbial exudates [1]. We monitored EH and pH along with flavin production (fluorescence measurements) during dissimilatory nitrate reduction to ammonium (DNRA). Dissolved flavins increased to 0.2 mM (riboflavin equivalent) under anoxic conditions during complete consumption of 1 mM nitrate by DNRA at pH 7.4 and 30 °C over 80 hours. The observed redox cascade from +255 to -250 mV did not follow the EH predicted for the reduction of NO3- to NO2- and NO2- to NH4+ by the Nernst equation. However, a set of separate abiotic experiments on the photoreduction of synthetic flavins (LMC, RF, FMN, and FAD, Sigma Aldrich) under the same conditions indicated that measured EH values are buffered at +270 ± 20 mV and -230 ± 50 mV when oxidized and reduced flavin species dominate, respectively. Moreover, based on the temporal changes in EH, we speculate that NO3- reduction by S. oneidensis consumes reduced flavins (i.e., NO3- accepts electrons from reduced flavins) and generates oxidized flavins, thus buffering EH at +255 mV. By contrast, NO2- reduction to NH4+ is independent of flavin speciation, which leads to the accumulation of reduced flavins in the solution and

  19. DMSP synthesis and exudation in phytoplankton : a modeling approach

    NARCIS (Netherlands)

    Laroche, D; Vézina, A.F; Levasseur, M; Gosselin, M; Stefels, J.; Keller, M.D; Matrai, P.A; Kwint, R.L J

    1999-01-01

    In the marine environment, phytoplankton are the fundamental producers of dimethylsulfoniopropionate (DMSP), the precursor of the climatically active gas dimethylsulfide (DMS). DMSP is released by exudation, cell autolysis, and zooplankton grazing during phytoplankton blooms. In this study, we

  20. Chemical composition of essential oil of exudates of Dryobalanops ...

    African Journals Online (AJOL)

    Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia, ... Gas chromatography-mass spectrometry (GC-MS) was used to characterize the ... Conclusion: Essential oil from the exudates of D. aromatica contains ..... industries.

  1. Automatic Detection of Retinal Exudates using a Support Vector Machine

    Directory of Open Access Journals (Sweden)

    Nualsawat HIRANSAKOLWONG

    2013-02-01

    Full Text Available Retinal exudates are among the preliminary signs of diabetic retinopathy, a major cause of vision loss in diabetic patients. Correct and efficient screening of exudates is very expensive in professional time and may cause human error. Nowadays, the digital retinal image is frequently used to follow-up and diagnoses eye diseases. Therefore, the retinal image is crucial and essential for experts to detect exudates. Unfortunately, it is a normal situation that retinal images in Thailand are poor quality images. In this paper, we present a series of experiments on feature selection and exudates classification using the support vector machine classifiers. The retinal images are segmented following key preprocessing steps, i.e., color normalization, contrast enhancement, noise removal and color space selection. On data sets of poor quality images, sensitivity, specificity and accuracy is 94.46%, 89.52% and 92.14%, respectively.

  2. Ubiquitous water-soluble molecules in aquatic plant exudates determine specific insect attraction.

    Directory of Open Access Journals (Sweden)

    Julien Sérandour

    Full Text Available Plants produce semio-chemicals that directly influence insect attraction and/or repulsion. Generally, this attraction is closely associated with herbivory and has been studied mainly under atmospheric conditions. On the other hand, the relationship between aquatic plants and insects has been little studied. To determine whether the roots of aquatic macrophytes release attractive chemical mixtures into the water, we studied the behaviour of mosquito larvae using olfactory experiments with root exudates. After testing the attraction on Culex and Aedes mosquito larvae, we chose to work with Coquillettidia species, which have a complex behaviour in nature and need to be attached to plant roots in order to obtain oxygen. This relationship is non-destructive and can be described as commensal behaviour. Commonly found compounds seemed to be involved in insect attraction since root exudates from different plants were all attractive. Moreover, chemical analysis allowed us to identify a certain number of commonly found, highly water-soluble, low-molecular-weight compounds, several of which (glycerol, uracil, thymine, uridine, thymidine were able to induce attraction when tested individually but at concentrations substantially higher than those found in nature. However, our principal findings demonstrated that these compounds appeared to act synergistically, since a mixture of these five compounds attracted larvae at natural concentrations (0.7 nM glycerol, <0.5 nM uracil, 0.6 nM thymine, 2.8 nM uridine, 86 nM thymidine, much lower than those found for each compound tested individually. These results provide strong evidence that a mixture of polyols (glycerol, pyrimidines (uracil, thymine, and nucleosides (uridine, thymidine functions as an efficient attractive signal in nature for Coquillettidia larvae. We therefore show for the first time, that such commonly found compounds may play an important role in plant-insect relationships in aquatic eco-systems.

  3. Detection of exudates in fundus imagery using a constant false-alarm rate (CFAR) detector

    Science.gov (United States)

    Khanna, Manish; Kapoor, Elina

    2014-05-01

    Diabetic retinopathy is the leading cause of blindness in adults in the United States. The presence of exudates in fundus imagery is the early sign of diabetic retinopathy so detection of these lesions is essential in preventing further ocular damage. In this paper we present a novel technique to automatically detect exudates in fundus imagery that is robust against spatial and temporal variations of background noise. The detection threshold is adjusted dynamically, based on the local noise statics around the pixel under test in order to maintain a pre-determined, constant false alarm rate (CFAR). The CFAR detector is often used to detect bright targets in radar imagery where the background clutter can vary considerably from scene to scene and with angle to the scene. Similarly, the CFAR detector addresses the challenge of detecting exudate lesions in RGB and multispectral fundus imagery where the background clutter often exhibits variations in brightness and texture. These variations present a challenge to common, global thresholding detection algorithms and other methods. Performance of the CFAR algorithm is tested against a publicly available, annotated, diabetic retinopathy database and preliminary testing suggests that performance of the CFAR detector proves to be superior to techniques such as Otsu thresholding.

  4. Foveal Exudative Macroaneurysm Treated with Intravitreal Ranibizumab

    Directory of Open Access Journals (Sweden)

    Carlos Menezes

    2015-06-01

    Full Text Available Purpose: We report a case of a foveal macroaneurysm with long-standing macular edema in a rare location, successfully treated with intravitreal ranibizumab. Methods: We report the case of a 52-year-old man with left eye long-term visual loss due to macular edema caused by a retinal macroaneurysm, localized about 400 μm from the center of the fovea, and its response to 6 monthly ranibizumab intravitreal injections. His best-corrected visual acuity and morphological data evaluated by optical coherence tomography and fluorescein angiography are presented. Results: His best-corrected visual acuity improved from 1/10 to 3/10 after the 3rd injection, and from 1/10 to 4/10 after the 6th one. The central retinal thickness was evaluated by optical coherence tomography and improved from 310 to 233 μm, with the resolution of both the associated serous detachments and the cystoid macular edema; an almost complete reabsorption of the hard exudates at the end of the treatment was also observed. The macroaneurysm lumen almost obliterated after the 3rd injection and completely collapsed at the end of treatment. Conclusions: Intravitreal ranibizumab may be effective in the treatment of long-standing macular edema associated with foveal macroaneurysms. To the best of our knowledge, this is the first report of a retinal macroaneurysm located so close to the foveal avascular zone.

  5. Clinical presentation of familial exudative vitreoretinopathy.

    Science.gov (United States)

    Ranchod, Tushar M; Ho, Lawrence Y; Drenser, Kimberly A; Capone, Antonio; Trese, Michael T

    2011-10-01

    To describe the clinical characteristics, staging and presentation of patients with familial exudative vitreoretinopathy (FEVR) in our clinical practice over the last 25 years. Case series, retrospective review. We included 273 eyes of 145 patients. Data collected from charts included gender, gestational age at birth, birthweight, age at presentation, referring diagnosis, family history, prior ocular surgery, and clinical presentation in each eye. Eyes with invasive posterior segment procedures before initial presentation were excluded. Demographics on presentation and clinical staging. Patients were slightly male predominant (57%) with a mean birthweight of 2.80 kg (range, 740 g-4.76 kg), mean gestational age of 37.8 weeks (range, 25-42), and mean age at presentation of almost 6 years (range, presentation, gestational age, and birthweight. Although a positive family history on presentation may support the diagnosis of FEVR, a negative family history is of little help. The majority of retinal folds extended radially in the temporal quadrants, but radial folds were seen in almost all quadrants. Fellow eyes demonstrated a wide variation in symmetry. The presentation of FEVR may mimic the presentation of other pediatric and adult vitreoretinal disorders, and careful examination is often crucial in making the diagnosis of FEVR. The authors have no proprietary or commercial interest in any of the materials discussed in this article. Copyright © 2011 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.

  6. Role of the plasma membrane H+-ATPase in the regulation of organic acid exudation under aluminum toxicity and phosphorus deficiency

    Science.gov (United States)

    Yu, Wenqian; Kan, Qi; Zhang, Jiarong; Zeng, Bingjie; Chen, Qi

    2016-01-01

    Aluminum (Al) toxicity and phosphorus (P) deficiency are 2 major limiting factors for plant growth and crop production in acidic soils. Organic acids exuded from roots have been generally regarded as a major resistance mechanism to Al toxicity and P deficiency. The exudation of organic acids is mediated by membrane-localized OA transporters, such as ALMT (Al-activated malate transporter) and MATE (multidrug and toxic compound extrusion). Beside on up-regulation expression of organic acids transporter gene, transcriptional, translational and post-translational regulation of the plasma membrane H+-ATPase are also involved in organic acid release process under Al toxicity and P deficiency. This mini-review summarizes the current knowledge about this field of study on the role of the plasma membrane H+-ATPase in organic acid exudation under Al toxicity and P deficiency conditions. PMID:26713714

  7. Role of the plasma membrane H(+)-ATPase in the regulation of organic acid exudation under aluminum toxicity and phosphorus deficiency.

    Science.gov (United States)

    Yu, Wenqian; Kan, Qi; Zhang, Jiarong; Zeng, Bingjie; Chen, Qi

    2016-01-01

    Aluminum (Al) toxicity and phosphorus (P) deficiency are 2 major limiting factors for plant growth and crop production in acidic soils. Organic acids exuded from roots have been generally regarded as a major resistance mechanism to Al toxicity and P deficiency. The exudation of organic acids is mediated by membrane-localized OA transporters, such as ALMT (Al-activated malate transporter) and MATE (multidrug and toxic compound extrusion). Beside on up-regulation expression of organic acids transporter gene, transcriptional, translational and post-translational regulation of the plasma membrane H(+)-ATPase are also involved in organic acid release process under Al toxicity and P deficiency. This mini-review summarizes the current knowledge about this field of study on the role of the plasma membrane H(+)-ATPase in organic acid exudation under Al toxicity and P deficiency conditions.

  8. A stable-isotope mass spectrometry-based metabolic footprinting approach to analyze exudates from phytoplankton

    DEFF Research Database (Denmark)

    Weber, Ralf J. M.; Selander, Erik; Sommer, Ulf

    2013-01-01

    Phytoplankton exudates play an important role in pelagic ecology and biogeochemical cycles of elements. Exuded compounds fuel the microbial food web and often encompass bioactive secondary metabolites like sex pheromones, allelochemicals, antibiotics, or feeding attractants that mediate biological...... interactions. Despite this importance, little is known about the bioactive compounds present in phytoplankton exudates. We report a stable-isotope metabolic footprinting method to characterise exudates from aquatic autotrophs. Exudates from 13C-enriched alga were concentrated by solid phase extraction...

  9. Short-Term Effects of Low Intensity Thinning on the Fine Root Dynamics of Pinus massoniana Plantations in the Three Gorges Reservoir Area, China

    Directory of Open Access Journals (Sweden)

    Yafei Shen

    2017-11-01

    Full Text Available Fine roots play an important role in plant growth as well as carbon (C and nutrient cycling in terrestrial ecosystems. Fine roots are important for understanding the contribution of forests to the global C cycle. Knowledge about this topic is still limited, especially regarding the effects of different forest management practices. This study investigated the seasonal dynamics of fine roots (<2 mm in masson pine (P. massoniana plantations for one year after low intensity thinning by using a sequential soil coring method. The fine roots showed pronounced seasonal dynamics, with a peak of fine root biomass (FRB occurring in September. Significant differences were noted in the seasonal dynamics of FRB for the different diameter size sub-classes (≤0.5 mm, 0.5–1 mm and 1–2 mm; also FRB was inversely related to soil depth. Moreover, the FRB (≤0.5 mm and 0.5–1 mm except 1–2 mm in the thinning plots was greater than that in the control only in the upper soil layer (0–10 cm. Furthermore, the FRB varied significantly with soil temperature, moisture and nutrients depended on the diameter sub-class considered. Significant differences in the soil temperature and moisture levels were noted between low-intensity thinned and control plots. Soil nutrient levels slightly decreased after low-intensity thinning. In addition, there was a more sensitive relationship between the very fine roots (diameter < 0.5 mm and soil nutrients. Our results showed an influence of low-intensity thinning on the fine root dynamics with a different magnitude according to fine root diameter sub-classes. These results provide a theoretical basis to promote the benefits of C cycling in the management of P. massoniana forests.

  10. Soil sheaths, photosynthate distribution to roots, and rhizosphere water relations for Opuntia ficus-indica

    Energy Technology Data Exchange (ETDEWEB)

    Huang, B.; North, G.B.; Nobel, P.S. (Univ. of California, Los Angeles, CA (United States))

    1993-09-01

    Soil sheaths incorporating aggregated soil particles surround young roots of many species, but the effects of such sheaths on water movement between roots and the soil are largely unknown. The quantity and location of root exudates associated with soil sheath along the entire length of its young roots, except within 1.4 cm of the tip. The soil sheaths, which average 0.7 mm in thickness, were composed of soil particles and root hairs, both of which were covered with exuded mucilaginous material. As determined with a [sup 14]C pulse-labeling technique, 2% of newly fixed [sup 14]C-photosynthate was translocated into the roots at 3d, 6% at 9 d, and 8% at 15 d after labeling. The fraction of insoluble [sup 14]C in the roots increased twofold from 3 d to 15 d. Over the same time period, 6%-9% of the [sup 14]C translocated to the roots was exuded into the soil. The soluble [sup 14]C compounds exuded into the soil were greater in the 3-cm segment at the root tip than elsewhere along the root, whereas mucilage was exuded relatively uniformly along roots 15 cm in length. The volumetric efflux of water increase for both sheathed and unsheathed roots as the soil water potential decreased form -0.1 MPa to -1.0 MPa. The efflux rate was greater for unsheathed roots than for sheathed roots, which were more turgid and had a higher water potential, especially at lower soil water potentials. During drying, soil particles in the sheaths aggregate more tightly, making the sheaths less permeable to water and possibly creating air gaps. The soil sheaths of O. ficus-indica thus reduce water loss from the roots to a drying soil. 34 refs., 6 figs., 1 tab.

  11. Measurement of pH, exudate composition and temperature in wound healing: a systematic review.

    Science.gov (United States)

    Power, G; Moore, Z; O'Connor, T

    2017-07-02

    To assess the potential of measurements of pH, exudate composition and temperature in wounds to predict healing outcomes and to identify the methods that are employed to measure them. A systematic review based on the outcomes of a search strategy of quantitative primary research published in the English language was conducted. Inclusion criteria limited studies to those involving in vivo and human participants with an existing or intentionally provoked wound, defined as 'a break in the epithelial integrity of the skin', and excluded in vitro and animal studies. Data synthesis and analysis was performed using structured narrative summaries of each included study arranged by concept, pH, exudate composition and temperature. The Evidence Based Literature (EBL) Critical Appraisal Checklist was implemented to appraise the quality of the included studies. A total of 23 studies, three for pH (mean quality score 54.48%), 12 for exudate composition (mean quality score 46.54%) and eight for temperature (mean quality score 36.66%), were assessed as eligible for inclusion in this review. Findings suggest that reduced pH levels in wounds, from alkaline towards acidic, are associated with improvements in wound condition. Metalloproteinase-9 (MMP-9), matrix metalloproteinase-2 (MMP-2), tissue inhibitor of metalloproteinase (TIMP), neutrophil elastase (NE) and albumin, in descending order, were the most frequently measured analytes in wounds. MMP-9 emerged as the analyte which offers the most potential as a biomarker of wound healing, with elevated levels observed in acute or non-healing wounds and decreasing levels in wounds progressing in healing. Combined measures of different exudate components, such as MMP/TIMP ratios, also appeared to offer substantial potential to indicate wound healing. Finally, temperature measurements are highest in non-healing, worsening or acute wounds and decrease as wounds progress towards healing. Methods used to measure pH, exudate composition and

  12. Vegetable exudates as food for Callithrix spp. (Callitrichidae: exploratory patterns.

    Directory of Open Access Journals (Sweden)

    Talitha Mayumi Francisco

    Full Text Available Marmosets of the genus Callithrix are specialized in the consumption of tree exudates to obtain essential nutritional resource by boring holes into bark with teeth. However, marmoset preferences for particular tree species, location, type, and other suitable factors that aid in exudate acquisition need further research. In the current study, the intensity of exudate use from Anadenanthera peregrina var. peregrina trees by hybrid marmosets Callithrix spp. groups was studied in five forest fragments in Viçosa, in the state of Minas, Brazil. Thirty-nine A. peregrina var. peregrina trees were examined and 8,765 active and non-active holes were analyzed. The trunk of A. peregrina var. peregrina had a lower number of holes than the canopy: 11% were found on the trunk and 89% were found on the canopy. The upper canopy was the preferred area by Callithrix spp. for obtaining exudates. The intensity of tree exploitation by marmosets showed a moderate-to-weak correlation with diameter at breast height (DBH and total tree height. The overall results indicate that Anadenanthera peregrina var. peregrina provides food resources for hybrid marmosets (Callithrix spp. and these animals prefer to explore this resource on the apical parts of the plant, where the thickness, location, and age of the branches are the main features involved in the acquisition of exudates.

  13. Importance of root HTO uptake in controlling land-surface tritium dynamics after an-acute HT deposition: a numerical experiment

    International Nuclear Information System (INIS)

    Ota, Masakazu; Nagai, Haruyasu; Koarashi, Jun

    2012-01-01

    To investigate the role of belowground root uptake of tritiated water (HTO) in controlling land-surface tritium (T) dynamics, a sophisticated numerical model predicting tritium behavior in an atmosphere-vegetation-soil system was developed, and numerical experiments were conducted using the model. The developed model covered physical tritiated hydrogen (HT) transport in a multilayered atmosphere and soil, as well as microbial oxidation of HT to HTO in the soil, and it was incorporated into a well-established HTO-transfer organically bound tritium (OBT)-formation model. The model performance was tested through the simulation of an existing HT-release experiment. Numerical experiments involving a hypothetical acute HT exposure to a grassland field with a range of rooting depths showed that the HTO release from the leaves to the atmosphere, driven by the root uptake of the deposited HTO, can exceed the HTO evaporation from the ground surface to the atmosphere when root water absorption preferentially occurs beneath the ground surface. Such enhanced soil-leaf-atmosphere HTO transport, caused by the enhanced root HTO uptake, increased HTO concentrations in both the surface atmosphere and in the cellular water of the leaf. Consequently, leaf OBT assimilation calculated for shallow rooting depths increased by nearly an order of magnitude compared to that for large rooting depths. - Highlights: ► A model that calculates HT deposition from atmosphere to soil was developed. ► Tritium dynamics after an-acute HT deposition was studied by numerical experiments. ► OBT formation highly depends on magnitude of uptake of the deposited HTO by roots.

  14. Root rots

    Science.gov (United States)

    Kathryn Robbins; Philip M. Wargo

    1989-01-01

    Root rots of central hardwoods are diseases caused by fungi that infect and decay woody roots and sometimes also invade the butt portion of the tree. By killing and decaying roots, root rotting fungi reduce growth, decrease tree vigor, and cause windthrow and death. The most common root diseases of central hardwoods are Armillaria root rot, lnonotus root rot, and...

  15. AUTOMATIC RETINA EXUDATES SEGMENTATION WITHOUT A MANUALLY LABELLED TRAINING SET

    Energy Technology Data Exchange (ETDEWEB)

    Giancardo, Luca [ORNL; Meriaudeau, Fabrice [ORNL; Karnowski, Thomas Paul [ORNL; Li, Yaquin [University of Tennessee, Knoxville (UTK); Tobin Jr, Kenneth William [ORNL; Chaum, Edward [University of Tennessee, Knoxville (UTK)

    2011-01-01

    Diabetic macular edema (DME) is a common vision threatening complication of diabetic retinopathy which can be assessed by detecting exudates (a type of bright lesion) in fundus images. In this work, two new methods for the detection of exudates are presented which do not use a supervised learning step and therefore do not require ground-truthed lesion training sets which are time consuming to create, difficult to obtain, and prone to human error. We introduce a new dataset of fundus images from various ethnic groups and levels of DME which we have made publicly available. We evaluate our algorithm with this dataset and compare our results with two recent exudate segmentation algorithms. In all of our tests, our algorithms perform better or comparable with an order of magnitude reduction in computational time.

  16. The impact of a diet with fructan-rich chicory roots on Oesophagostomum dentatum worm population dynamics and host immune responses in pigs

    DEFF Research Database (Denmark)

    Thamsborg, Stig Millan; Mejer, Helena; Skovgaard, Kerstin

    Oesophagostomum infections in pigs persist for months. We hypothesized that feeding fructans (dried chicory roots) may improve immunity and facilitate worm expulsion. We therefore examined the effects of long-term chicory on O. dentatum population dynamics and host immune responses. Methods: Seve...

  17. Differentiation of exudative and transudative pleural effusion : MR appearances

    International Nuclear Information System (INIS)

    Kim, Tae Hoon; Lee, Sang Yoon; Kang, Ho Yeong; Kim, Soo Rhan; Yang, Sang Kyu; Shin, So Young; Lee, Shin Hyung; Lee, Chang Joon

    1996-01-01

    The purpose of this study is to determine whether MR images after intravenous administration of Gd-DTPA can differentiate exudative and transudative pleural effusion. We studied 18 patients with ten exudative and eight transudative pleural effusions diagnosed clinically and by thoracentesis. We analysed the relationship between T1 value(normalized to fat) and the ratio of effusion/serum protein of pleural effusion. We also assessed the contrast enhancement of exudative and transudative pleural effusion on T1 weighted SE images taken at 15 and 30minutes after administration of Gd-DTPA. The relationship between the effusion/serum protein ratio and T1 value(normalized to fat) was statistically not significant(r=0.27, P=0.381). On precontrast spin-echo T1WI, mean signal intensity of the transudate was 0.18(±0.04) and that of the exudate was 0.24(±0.07), values which were not significant differences(P>0.05). Postcontrast mean signal intensities of transudates at 15 and 30 were 0.20±0.06 and 0.26±0.08, respectively, values which were not significantly higher than that of precontrast mean signal intensity(P<0.05). Postcontrast mean signal intensity values of exudative pleural effusions at 15 and 30 minutes(0.32±0.06 and 0.39±0.06, respectively) were, on the other hand, significantly higher than that of precontrast mean signal intensity(P<0.05). Postcontrast T1-weighted SE images at 15 and 30 minutes can be helpful in the differentiation of transudative and exudative pleural effusion

  18. Root cortical aerenchyma inhibits radial nutrient transport in maize (Zea mays).

    Science.gov (United States)

    Hu, Bo; Henry, Amelia; Brown, Kathleen M; Lynch, Jonathan P

    2014-01-01

    Formation of root cortical aerenchyma (RCA) can be induced by nutrient deficiency. In species adapted to aerobic soil conditions, this response is adaptive by reducing root maintenance requirements, thereby permitting greater soil exploration. One trade-off of RCA formation may be reduced radial transport of nutrients due to reduction in living cortical tissue. To test this hypothesis, radial nutrient transport in intact roots of maize (Zea mays) was investigated in two radiolabelling experiments employing genotypes with contrasting RCA. In the first experiment, time-course dynamics of phosphate loading into the xylem were measured from excised nodal roots that varied in RCA formation. In the second experiment, uptake of phosphate, calcium and sulphate was measured in seminal roots of intact young plants in which variation in RCA was induced by treatments altering ethylene action or genetic differences. In each of three paired genotype comparisons, the rate of phosphate exudation of high-RCA genotypes was significantly less than that of low-RCA genotypes. In the second experiment, radial nutrient transport of phosphate and calcium was negatively correlated with the extent of RCA for some genotypes. The results support the hypothesis that RCA can reduce radial transport of some nutrients in some genotypes, which could be an important trade-off of this trait.

  19. [Surgical treatment of patients with exudative otitis media].

    Science.gov (United States)

    Dmitriev, N S; Mileshina, N A

    2003-01-01

    The article concerns peculiarities of surgery for chronic exudative otitis media (CEOM). The significance of miringotomy, tympanostomy, tympanotomy and tympanoantrotomy is demonstrated. The experience of the authors in surgical treatment and postoperative management of CEOM is reviewed. Of primary importance is valid selection of patients for each operation and choice of ventilatory tubes depending on the disease stage. Incidence rate and causes of recurrences in respect to the patients' age are presented and the role of follow-up in prevention of CEOM recurrences is shown. Use of temporal bone computed tomography in CEOM is specified. Key words: exudative otitis media, tympanostomy, ventilation tubes, CT of the temporal bone.

  20. Hard Retinal exudates and visual loss due to papilledema

    International Nuclear Information System (INIS)

    Rush, J.A.

    1982-01-01

    Bilateral papilledema developed in a patient with a cystic, grade 3 astrocytoma of the right frontal lobe. Despite successful neurosurgical treatment, 60 Co radiotherapy, and oral corticosteroid therapy, progressive visual loss occurred. At examination one year later, visual activity was 20/200 and 20/70, and extensive lipid exudates in the peripapillary retina and central macula of each eye were noted. Retinal lipid exudates rarely complicate the course of surviving patients who had papilledema from intracranial tumor; physicians involved in the multispecialty care of such patients should be aware of the possible ocular residuals of persistent papilledema in an otherwise successfully treated patient

  1. Adsorption and absorption of polycyclic aromatic hydrocarbons to rice roots

    International Nuclear Information System (INIS)

    Jiao, X.C.; Xu, F.L.; Dawson, R.; Chen, S.H.; Tao, S.

    2007-01-01

    Rice roots and surrounding air, soil and water samples were collected for polycyclic aromatic hydrocarbon (PAH) analysis. The rice roots were separated into lateral roots and nodal roots, and the PAH concentration in the former was found to be higher than that in the latter. In addition, root physiological characteristics including root biotic mass, root lipid content and specific surface area are also discussed. When normalizing the total, adsorption and absorption PAH fractions on a dry root weight basis to root biomass, root lipid, and surface area bases respectively, the differences between PAHs in the two types of roots diminished by 2 to 3 times on average. Results from sequential extraction indicated that PAHs were more easily absorbed by interior rice roots than adsorbed on the surface. In addition, more than 60% of total PAHs accumulated in root tissue for both lateral and nodal roots. However, the results were highly related to the solvent used, extraction time and methodology. Correlation analysis between bioconcentration factors (root over environment) and K OA , K OW showed water to be more significant for PAH adsorption in rice roots than other environmental media. - A sequential extraction method was applied to divide the PAHs accumulated on rice roots into PAHs in root exudates, PAHs adsorbed on root surfaces, and PAHs absorbed in root tissue

  2. The Impact of Rhizosphere Processes on Water Flow and Root Water Uptake

    Science.gov (United States)

    Schwartz, Nimrod; Kroener, Eva; Carminati, Andrea; Javaux, Mathieu

    2015-04-01

    For many years, the rhizosphere, which is the zone of soil in the vicinity of the roots and which is influenced by the roots, is known as a unique soil environment with different physical, biological and chemical properties than those of the bulk soil. Indeed, in recent studies it has been shown that root exudate and especially mucilage alter the hydraulic properties of the soil, and that drying and wetting cycles of mucilage result in non-equilibrium water dynamics in the rhizosphere. While there are experimental evidences and simplified 1D model for those concepts, an integrated model that considers rhizosphere processes with a detailed model for water and roots flow is absent. Therefore, the objective of this work is to develop a 3D physical model of water flow in the soil-plant continuum that take in consideration root architecture and rhizosphere specific properties. Ultimately, this model will enhance our understanding on the impact of processes occurring in the rhizosphere on water flow and root water uptake. To achieve this objective, we coupled R-SWMS, a detailed 3D model for water flow in soil and root system (Javaux et al 2008), with the rhizosphere model developed by Kroener et al (2014). In the new Rhizo-RSWMS model the rhizosphere hydraulic properties differ from those of the bulk soil, and non-equilibrium dynamics between the rhizosphere water content and pressure head is also considered. We simulated a wetting scenario. The soil was initially dry and it was wetted from the top at a constant flow rate. The model predicts that, after infiltration the water content in the rhizosphere remained lower than in the bulk soil (non-equilibrium), but over time water infiltrated into the rhizosphere and eventually the water content in the rhizosphere became higher than in the bulk soil. These results are in qualitative agreement with the available experimental data on water dynamics in the rhizosphere. Additionally, the results show that rhizosphere processes

  3. Active learning approach for detection of hard exudates, cotton wool spots, and drusen in retinal images

    Science.gov (United States)

    Sánchez, Clara I.; Niemeijer, Meindert; Kockelkorn, Thessa; Abràmoff, Michael D.; van Ginneken, Bram

    2009-02-01

    Computer-aided Diagnosis (CAD) systems for the automatic identification of abnormalities in retinal images are gaining importance in diabetic retinopathy screening programs. A huge amount of retinal images are collected during these programs and they provide a starting point for the design of machine learning algorithms. However, manual annotations of retinal images are scarce and expensive to obtain. This paper proposes a dynamic CAD system based on active learning for the automatic identification of hard exudates, cotton wool spots and drusen in retinal images. An uncertainty sampling method is applied to select samples that need to be labeled by an expert from an unlabeled set of 4000 retinal images. It reduces the number of training samples needed to obtain an optimum accuracy by dynamically selecting the most informative samples. Results show that the proposed method increases the classification accuracy compared to alternative techniques, achieving an area under the ROC curve of 0.87, 0.82 and 0.78 for the detection of hard exudates, cotton wool spots and drusen, respectively.

  4. A mathematical model for investigating the effect of cluster roots on plant nutrient uptake

    KAUST Repository

    Zygalakis, K. C.

    2012-04-01

    Cluster roots are thought to play an important role in mediating nutrient uptake by plants. In this paper we develop a mathematical model for the transport and uptake of phosphate by a single root. Phosphate is assumed to diffuse in the soil fluid phase and can also solubilised due to citrate exudation. Using multiple scale homogenisation techniques we derive an effective model that accounts for the cumulative effect of citrate exudation and phosphate uptake by cluster roots whilst still retaining all the necessary information about the microscale geometry and effects. © 2012 EDP Sciences and Springer.

  5. Reduction of Exudates (Browning) in Sugarcane Micro Propagation ...

    African Journals Online (AJOL)

    ... of this variety, ascorbic acid and citric acid was added as constituent of the media using MS and stock at different concentrations. The browning was reduced drastically at the addition of 0.1g/litre ascorbic acid and 0.15g/litre citric acid. Keywords: reduction, exudates browning, micro propagation, sugarcane. Nig J. Biotech.

  6. Zoospore exudates from Phytophthora nicotianae affect immune responses in Arabidopsis.

    Science.gov (United States)

    Kong, Ping; McDowell, John M; Hong, Chuanxue

    2017-01-01

    Zoospore exudates play important roles in promoting zoospore communication, homing and germination during plant infection by Phytophthora. However, it is not clear whether exudates affect plant immunity. Zoospore-free fluid (ZFF) and zoospores of P. nicotianae were investigated comparatively for effects on resistance of Arabidopsis thaliana Col-0 and mutants that affect signaling mediated by salicylic acid (SA) and jasmonic acid (JA): eds16 (enhanced disease susceptibility16), pad4 (phytoalexin deficient4), and npr1 (nonexpressor of pathogenesis-related genes1). Col-0 attracted more zoospores and had severe tissue damage when flooded with a zoospore suspension in ZFF. Mutants treated with ZFF alone developed disease symptoms similar to those inoculated with zoospores and requirements of EDS16 and PAD4 for plant responses to zoospores and the exudates was apparent. Zoospore and ZFFs also induced expression of the PR1 and PDF1.2 marker genes for defense regulated by SA and JA, respectively. However, ZFF affected more JA defense signaling, down regulating PR1 when SA signaling or synthesis is deficient, which may be responsible for Arabidopsis mutant plants more susceptible to infection by high concentration of P. nicotianae zoospores. These results suggest that zoospore exudates can function as virulence factors and inducers of plant immune responses during plant infection by Phytophthora.

  7. Antioxidant activity of the exudate from Aloe barbadensis leaves in ...

    African Journals Online (AJOL)

    The effects of the exudate of Aloe barbadensis leaves on oxidative stress and some antioxidant status of streptozotocin induced - diabetic rats were studied. There was significant reduction in scavenging enzymes like superoxide dismutase (SOD) activity and significant increase in signs of oxidative tissue damage, such as ...

  8. Classification of visualization exudates fundus images results using ...

    African Journals Online (AJOL)

    The kernel function settings; linear, polynomial, quadratic and RBF have an effect on the classification results. For SVM1, the best parameter in classifying pixels is linear kernel function. The visualization results using CAC and radar chart are classified using ts accuracy. It has proven to discriminated exudates and non ...

  9. Anti-Atherogenicity Following Administration of Exudate from Aloe ...

    African Journals Online (AJOL)

    Anti-Atherogenicity Following Administration of Exudate from Aloe barbadensis Leaves in Diabetic Rats. HU Nwanjo, GO Oze. Abstract. No Abstract. Full Text: EMAIL FULL TEXT EMAIL FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT · AJOL African Journals Online. HOW TO USE AJOL... for Researchers ...

  10. Zoospore exudates from Phytophthora nicotianae affect immune responses in Arabidopsis.

    Directory of Open Access Journals (Sweden)

    Ping Kong

    Full Text Available Zoospore exudates play important roles in promoting zoospore communication, homing and germination during plant infection by Phytophthora. However, it is not clear whether exudates affect plant immunity. Zoospore-free fluid (ZFF and zoospores of P. nicotianae were investigated comparatively for effects on resistance of Arabidopsis thaliana Col-0 and mutants that affect signaling mediated by salicylic acid (SA and jasmonic acid (JA: eds16 (enhanced disease susceptibility16, pad4 (phytoalexin deficient4, and npr1 (nonexpressor of pathogenesis-related genes1. Col-0 attracted more zoospores and had severe tissue damage when flooded with a zoospore suspension in ZFF. Mutants treated with ZFF alone developed disease symptoms similar to those inoculated with zoospores and requirements of EDS16 and PAD4 for plant responses to zoospores and the exudates was apparent. Zoospore and ZFFs also induced expression of the PR1 and PDF1.2 marker genes for defense regulated by SA and JA, respectively. However, ZFF affected more JA defense signaling, down regulating PR1 when SA signaling or synthesis is deficient, which may be responsible for Arabidopsis mutant plants more susceptible to infection by high concentration of P. nicotianae zoospores. These results suggest that zoospore exudates can function as virulence factors and inducers of plant immune responses during plant infection by Phytophthora.

  11. A case of apathetic hyperthyroidism with exudative low SAAG ascites

    Directory of Open Access Journals (Sweden)

    Seyed Masood Tabib

    2009-12-01

    In this case report, we present a 73-year-old man who was referred to us with anorexia, severe weight loss, anemia, lower limbs pitting edema, and also exudative, low SAAG ascites. Extensive work up revealed that these constellation of signs & symptoms were consequent to decompensation of his chronic right-sided heart failure resulting from apathetic hyperthyroidism.

  12. New phenolic esters from the resinous exudate of Haplopappus taeda.

    Science.gov (United States)

    Faini, Francesca; Labbé, Cecilia; Torres, René; Rodilla, Jesús M; Silva, Lucía; Delle Monache, Franco

    2007-12-01

    Two new phenolic esters 9-trans-p-coumaroyloxy-alpha-terpineol (1) and 7-trans-p-coumaroyloxy-taedol (2), both endowed with free radical scavenger activity and cleroda-3,13 (E)-dien-15,18-diol (3) for which a cis stereochemistry at the decalin junction was found, were isolated from the resinous exudate from Haplopappus taeda upper parts.

  13. Evaluation of Biomass Yield and Water Treatment in Two Aquaponic Systems Using the Dynamic Root Floating Technique (DRF

    Directory of Open Access Journals (Sweden)

    Laura Silva

    2015-11-01

    Full Text Available The experiment evaluates the food production and water treatment of TAN, NO2−–N, NO3−–N, and PO43− in two aquaponics systems using the dynamic root floating technique (DRF. A separate recirculation aquaculture system (RAS was used as a control. The fish cultured was Nile tilapia (Oreochromis niloticus. The hydroponic culture in one treatment (PAK was pak choy (Brassica chinensis, and in the other (COR coriander (Coriandrum sativum. Initial and final weights were determined for the fish culture. Final edible fresh weight was determined for the hydroponic plant culture. TAN, NO2−–N, NO3−–N, and PO43− were measured in fish culture and hydroponic culture once a week at two times, morning (9:00 a.m. and afternoon (3:00 p.m.. The fish biomass production was not different in any treatment (p > 0.05 and the total plant yield was greater (p < 0.05 in PAK than in COR. For the hydroponic culture in the a.m., the PO43− was lower (p < 0.05 in the PAK treatment than in COR, and in the p.m. NO3−–N and PO43− were lower (p < 0.05 in PAK than in COR. The PAK treatment demonstrated higher food production and water treatment efficiency than the other two treatments.

  14. Diagnosis of non-exudative (DRY) age related macular degeneration by non-invasive photon-correlation spectroscopy.

    Science.gov (United States)

    Fankhauser, Franz Ii; Ott, Maria; Munteanu, Mihnea

    2016-01-01

    Photon-correlation spectroscopy (PCS) (quasi-elastic light scattering spectroscopy, dynamic light scattering spectroscopy) allows the non-invasively reveal of local dynamics and local heterogeneities of macromolecular systems. The capability of this technique to diagnose the retinal pathologies by in-vivo investigations of spatial anomalies of retinas displaying non-exudative senile macular degeneration was evaluated. Further, the potential use of the technique for the diagnosis of the macular degeneration was analyzed and displayed by the Receiver Operating Curve (ROC). The maculae and the peripheral retina of 73 normal eyes and of 26 eyes afflicted by an early stage of non-exudative senile macular degeneration were characterized by time-correlation functions and analyzed in terms of characteristic decay times and apparent size distributions. The characteristics of the obtained time-correlation functions of the eyes afflicted with nonexudative macular degeneration and of normal eyes differed significantly, which could be referred to a significant change of the nano- and microstructure of the investigated pathologic maculas. Photon-correlation spectroscopy is able to assess the macromolecular and microstructural aberrations in the macula afflicted by non-exudative, senile macular degeneration. It has been demonstrated that macromolecules of this disease show a characteristic abnormal behavior in the macula.

  15. Simulated root dynamics of a 160-year-old sugar maple (Acer saccharum Marsh.) tree with and without ozone exposure using the TREGRO model.

    Science.gov (United States)

    Retzlaff, W. A.; Weinstein, D. A.; Laurence, J. A.; Gollands, B.

    1996-01-01

    Because of difficulties in directly assessing root responses of mature forest trees exposed to atmospheric pollutants, we have used the model TREGRO to analyze the effects of a 3- and a 10-year exposure to ozone (O(3)) on root dynamics of a simulated 160-year-old sugar maple (Acer saccharum Marsh.) tree. We used existing phenological, allometric, and growth data to parameterize TREGRO to produce a simulated 160-year-old tree. Simulations were based on literature values for sugar maple fine root production and senescence and the photosynthetic responses of sugar maple seedlings exposed to O(3) in open-top chambers. In the simulated 3-year exposure to O(3), 2 x ambient atmospheric O(3) concentrations reduced net carbon (C) gain of the 160-year-old tree. This reduction occurred in the C storage pools (total nonstructural carbohydrate, TNC), with most of the reduction occurring in coarse (woody) roots. Total fine root production and senescence were unaffected by the simulated 3-year exposure to O(3). However, extending the simulated O(3) exposure period to 10 years depleted the TNC pools of the coarse roots and reduced total fine root production. Similar reductions in TNC pools have been observed in forest-grown sugar maple trees exhibiting symptoms of stress. We conclude that modeling can aid in evaluating the belowground response of mature forest trees to atmospheric pollution stress and could indicate the potential for gradual deterioration of tree health under conditions of long-term stress, a situation similar to that underlying the decline of sugar maple trees.

  16. Pleural mesothelioma in differential diagnostics of a tubercular exudative pleuritis

    Directory of Open Access Journals (Sweden)

    O.M. Raznatovskaya

    2017-02-01

    Full Text Available Background. Difficulties of differential diagnostics of exudative pleuritis due to pleura mesothelioma and such one of tubercular etiology can take a long time that is the reason of delayed well-timed and correct treatment order. Etiological diagnostics of exudative pleuritis has to be based on an integrated approach taking into account the data of clinical inspection of a patient, a laboratory research of pleural exudate, radial, instrumental, pathomorphological and surgical methods. The aim of our study is to establish the features of diagnosis of exudative pleuritis due to pleura mesothelioma by determining of informativeness and value of applied diagnostic methods for further use for differential diagnostics with exudative pleuritis of tubercular etiology on the cases of own clinical observations. Materials and methods. Four clinical cases of diagnostics of pleura mesothelioma in the patients with exudative pleuritis at Municipal Institution “Zaporizhzhia Regional Antituberculous Clinical Dispensary” were analyzed. Results. Four cases of pleura mesothelioma were diagnosed at Municipal Institution “Zaporizhzhia Regional Antituberculous Clinical Dispensary” within differential diagnostics of exudative pleuritis of obscure origin. In all cases the following similar features of pleura mesothelioma were observed: patients were male; patients complained about dyspnoea at exercise stress, thorax pain (on the side of mesothelioma localization, general weakness, periodic cough; the patients denied tuberculosis contact; the general blood test revealed only lymphopenia against the background of the accelerated ESR; micobacteria of tuberculosis were not revealed at all; steady accumulation of an exudate, despite its systematic evacuation; cytologic research of pleural liquid was characterized by a moderate turbidity, serous (serous and hemorrhagic character, with the specific weight of 1015–1016, rising of protein to 33–66 g/l, positive

  17. Carboxy methylation of cashew nut tree exudate gum

    International Nuclear Information System (INIS)

    Silva, Durcilene A. da; Paula, Regina C.M.

    2001-01-01

    Anacardium occidentale exudate polysaccharide was carboxymethylated with monochloroacetic acid. The samples were characterized by NMR, solution viscometry, GPC and thermal analysis. Carboxymethylated cashew gum (CMGC) with a degree of substitution between 0,1-0,16 was obtained. Solution viscometry and GPC analysis showed that polymer molar mass degradation occurred. Sample with higher DS shows higher peak molar mass, intrinsic viscosity and thermal stability. NMR spectrum indicated that the carboxy methylation reaction occurs preferentially in C-6 of galactose residue. (author)

  18. Heliotropium huascoense resin exudate: chemical constituents and defensive properties.

    Science.gov (United States)

    Villarroel, L; Torres, R; Urzúa, A; Reina, M; Cabrera, R; González-Coloma, A

    2001-09-01

    From the resinous exudate of Heliotropium huascoense a new compound, rel-(8R,9R)-carrizaloic acid, (1) (3-[rel-(8R,9R-9-hydroxy-9,13,13-trimethyl-12-oxo-10-cyclohexenyl)methyl]-4-methoxybenzoic acid), and three known flavonoids, [3-methylgalangin, 3,7-dimethylgalangin, and (-)-alpinone] have been isolated. The structure of 1 was determined by spectral and chemical methods. Several plant defensive properties of 1 (insecticidal and antifungal) have been evaluated.

  19. Diagnostic yield of pleural biopsy in exudative pleural effusion.

    Science.gov (United States)

    Devkota, K C; Chokhani, R; Gautam, S

    2014-09-01

    To know the diagnostic role of pleural biopsy in determining underlying etiological causes of exudative pleural effusion. A total of 47 patients, aged 16-104 years with mean age of 47.36 years, of either sex, with exudative pleural effusion underwent closed pleural biopsy with Abram's needle in standard way. Average 4-6 biopsy specimens were obtained from each patient, which were sent for histopathological examination. In this study, 47 cases of exudative pleural effusion were included, among them 26 (55.31%) cases were male and 21 (44.69%) were female with mean age 47.36 years. Cough was reported by 42 (89.36%) cases, expectoration 28 (59.57%), hemoptysis 3 (6.38%), breathlessness 27 (57.44%), wheezing 3 (6.38%), chest pain 38 (80.85%) and fever by 30 (63.82%) cases. Out of 47 cases, 28 (59.57%) cases had a positive yield, whereas in 19 (40.43%) cases the result was nonspecific inflammation. Out of 28 (59.57%) cases with positive yield 21 (44.68%) were found to have granulomatous inflammation and 10 (21.28%) cases were malignant. Among malignant pleural effusion, 4 cases were squamous cell carcinoma; 3 small cell carcinoma; 1 case adenocarcinoma and 1 case found to have mesothelioma. Tuberculosis and malignancy are the two most common causes of exudative pleural effusion in our set up. Pleural biopsy is a safe, simple and well validated diagnostic tool that helps us to differentiate between malignancy and tuberculosis.

  20. Ultrasound guided pleural biopsy in undiagnosed exudative pleural effusion patients

    OpenAIRE

    Adel S. Ahmed; Mostafa I. Ragab; Alaa eldin M. Elgazaar; Nagwan A. Ismail

    2016-01-01

    Introduction: Pleural biopsy for pathological confirmation is the standard diagnostic procedure for pleural diseases, transthoracic ultrasonography (TUS) has evolved as an important imaging tool for diagnosing pleural and pulmonary conditions. Aim of the study: To assess the diagnostic yield of TUS guided pleural biopsy versus both CT guided and thoracoscopic pleural biopsy in the diagnosis of undiagnosed exudative pleural effusion. Patients and methods: The study was conducted at chest...

  1. Treeline advances and associated shifts in the ground vegetation alter fine root dynamics and mycelia production in the South and Polar Urals.

    Science.gov (United States)

    Solly, Emily F; Djukic, Ika; Moiseev, Pavel A; Andreyashkina, Nelly I; Devi, Nadezhda M; Göransson, Hans; Mazepa, Valeriy S; Shiyatov, Stepan G; Trubina, Marina R; Schweingruber, Fritz H; Wilmking, Martin; Hagedorn, Frank

    2017-02-01

    Climate warming is shifting the elevational boundary between forests and tundra upwards, but the related belowground responses are poorly understood. In the pristine South and Polar Urals with shifts of the treeline ecotone documented by historical photographs, we investigated fine root dynamics and production of extramatrical mycorrhizal mycelia (EMM) along four elevational transects reaching from the closed forest to the treeless tundra. In addition, we analysed elevational differences in climate and vegetation structure, and excavated trees to estimate related changes in the partitioning between below- and aboveground biomass. Fine root biomass of trees (<2 mm) increased by 13-79% with elevation, paralleled by a 35-72% increase in ground vegetation fine roots from the closed forest to the tundra. During the first year of decomposition, mass loss of fine root litter from different vegetation types was greater at lower elevations in the forest-tundra ecotone. The ratio between fine roots of trees and stem biomass largely increased with elevation in both regions, but these increases were not accompanied by a distinct production of EMM. Production of EMM, however, increased with the presence of ectomycorrhizal trees at the transition from the tundra to the forest. Our results imply that the recorded upward expansion of forest into former tundra in the Ural Mountains by 4-8 m per decade is decreasing the partitioning of plant biomass to fine roots. They further suggest that climate-driven forest advances will alter EMM production rates with potential feedbacks on soil carbon and nutrient cycling in these ecosystems.

  2. Evaluation of lymphocytic exudative pleural effusion with pleural biopsy

    International Nuclear Information System (INIS)

    Khurram, M.; Jaffery, A.H.; Khar, Hamama-tul-Bushra; Malik, M.F.; Javed, S.; Burki, U.F.; Khan, B.A.; Ali, A.

    2002-01-01

    Objective: Evaluation of lymphocytic exudative pleural effusion by histopathological examination of pleural biopsy in patients with suspected tuberculous or malignant pleural effusion. Place and Duration of Study: The study was conducted at Pulmonology Department, Pakistan Institute of Medical Sciences, Islamabad and DHQ Teaching Hospital, Rawalpindi for two years 1999-2000. Subjects and Methods: A total of 120 patients with exudative pleural effusion underwent closed pleural biopsy with Abram's needle in standard way. Average 4 biopsy specimens were obtained in each patient which were examined histopathologically. Patients in whom a definite diagnosis was not possible were further investigated with repeat pleural biopsy, sputum examinations, bronchoscopy etc. Results definite histopathological diagnosis with pleural biopsy was possible in 59 (49.16% patients, including 13 diagnosed on repeat pleural biopsy. Two commonest diagnoses made were tuberculosis and adenocarcinoma, 64.40% and 13.55% respectively. Conclusion: Histopathological evaluation of pleural biopsy specimens can lead to diagnosis in 49.16% patients with exudative lymphocytic pleural effusion. (author)

  3. The meaning of living with malodorous exuding ulcers.

    Science.gov (United States)

    Lindahl, Elisabeth; Norberg, Astrid; Söderberg, Anna

    2007-03-01

    This study illuminates the meaning of living with malodorous, exuding ulcers. Difficulties for patients with chronic ulcers and the ulcers' impact on patients' daily life are described in the literature. Suffering and consolation are also addressed in the literature as important issues in nursing care. The first author interviewed seven women and two men, aged 41-95, with various diagnoses. We interpreted the transcribed interviews using a phenomenological hermeneutic method. Two processes were identified: 'being struck down'- themes: feeling dirty, being trapped, losing confidence, losing hope, becoming frustrated and protecting oneself; and 'finding consolation'- themes: experiencing kinship, encountering genuineness and gaining control. The meaning of living with malodorous and exuding ulcers can be understood as being trapped in a debilitating process that slowly strikes one down. There is a longing for purity and wholeness and for one's life to improve. When people with malodorous, exuding ulcers encounter genuineness and feel loved, regarded and respected as fully human despite their ulcers, they feel purified. The contaminated body no longer contaminates their self-image and self-esteem and they feel restored and fully human again. Only when they feel fully human can they regain control and see life beyond their ulcers. Although nurses cannot make ulcers or smell disappear, they can contribute significantly to improve the patients' life. Finding consolation makes patients feel purified despite their contaminated body. This study points to the importance of seeing the human being beyond the ulcer and considering not only the body but the whole person.

  4. A multiscale optimization approach to detect exudates in the macula.

    Science.gov (United States)

    Agurto, Carla; Murray, Victor; Yu, Honggang; Wigdahl, Jeffrey; Pattichis, Marios; Nemeth, Sheila; Barriga, E Simon; Soliz, Peter

    2014-07-01

    Pathologies that occur on or near the fovea, such as clinically significant macular edema (CSME), represent high risk for vision loss. The presence of exudates, lipid residues of serous leakage from damaged capillaries, has been associated with CSME, in particular if they are located one optic disc-diameter away from the fovea. In this paper, we present an automatic system to detect exudates in the macula. Our approach uses optimal thresholding of instantaneous amplitude (IA) components that are extracted from multiple frequency scales to generate candidate exudate regions. For each candidate region, we extract color, shape, and texture features that are used for classification. Classification is performed using partial least squares (PLS). We tested the performance of the system on two different databases of 652 and 400 images. The system achieved an area under the receiver operator characteristic curve (AUC) of 0.96 for the combination of both databases and an AUC of 0.97 for each of them when they were evaluated independently.

  5. RUNTIME DICTIONARIES FOR ROOT

    CERN Document Server

    Wind, David Kofoed

    2013-01-01

    ROOT is the LHC physicists' common tool for data analysis; almost all data is stored using ROOT's I/O system. This system benefits from a custom description of types (a so-called dictionary) that is optimised for the I/O. Until now, the dictionary cannot be provided at run-time; it needs to be prepared in a separate prerequisite step. This project will move the generation of the dictionary to run-time, making use of ROOT 6's new just-in-time compiler. It allows a more dynamic and natural access to ROOT's I/O features especially for user code.

  6. ASSOCIATION BETWEEN RETINAL HARD EXUDATES AND DYSLIPIDEMIA IN TYPE 2 DIABETIC PATIENTS IN RURAL KARNATAKA

    Directory of Open Access Journals (Sweden)

    Arun Kumar B.

    2015-10-01

    Full Text Available AIM: To evaluate the association of elevated serum lipids with retinal hard exudates in type 2 diabetic patients in rural Karnataka. MATERIAL AND METHODS : Hospital based cross sectional study which included 60 (n=60 type 2 diabetic patients (60 eyes fulfilling the inclusion criteria. Patients were subjected to detailed ocular examination, fundus examination done under full dilatation using indirect ophth almoscope with 20D lens and slit lamp biomicroscope with 90D lens. Fundus photographs were obtained using fundus camera. Grading of retinal hard exudates performed by utilizing modified Airlie House classification. The modified Airlie House Classification used is as follows: Grade 0 - No evidence of hard exudates; Grade 1 : Questionable hard exudates present; Grade 2 : Hard exudates less than standard photograph 3; Grade 3 : Hard exudates greater than or equal to standard photograph 3, but less than standard p hotograph 5; Grade 4 : Hard exudates greater than or equal to standard photograph 5, but less than standard photograph 4 and Grade 5 : Hard exudates greater than or equal to standard photograph 4. These grades were further divided into three groups of patie nt severity as follows: Group 1 (absent or minimal hard exudates included patients with Grade 0, 1 or 2 hard exudates; Group 2 (hard exudates present included patients with Grade 3 or 4 hard exudates and Group 3 (prominent hard exudates included patient s with Grade 5 hard exudates. Fasting lipid profile including serum total cholesterol, low density lipoproteins, very low density lipoproteins, high density lipoproteins and triglycerides was obtained. Association of dyslipidemia with retinal hard exudates was analysed using one way ANOVA test. RESULTS: On statistical analysis with ANOVA test retinal hard exudates were significantly associated with elevated total cholesterol (p= .0001, triglycerides (p= .0001, serum LDL (p=.008, serum VLDL (p=.012, and negative correlation was found

  7. The amino acid distribution in rachis xylem sap and phloem exudate of Vitis vinifera 'Cabernet Sauvignon' bunches.

    Science.gov (United States)

    Gourieroux, Aude M; Holzapfel, Bruno P; Scollary, Geoffrey R; McCully, Margaret E; Canny, Martin J; Rogiers, Suzy Y

    2016-08-01

    Amino acids are essential to grape berry and seed development and they are transferred to the reproductive structures through the phloem and xylem from various locations within the plant. The diurnal and seasonal dynamics of xylem and phloem amino acid composition in the leaf petiole and bunch rachis of field-grown Cabernet Sauvignon are described to better understand the critical periods for amino acid import into the berry. Xylem sap was extracted by the centrifugation of excised leaf petioles and rachises, while phloem exudate was collected by immersing these structures in an ethylenediaminetetraacetic acid (EDTA) buffer. Glutamine and glutamic acid were the predominant amino acids in the xylem sap of both grapevine rachises and petioles, while arginine and glycine were the principal amino acids of the phloem exudate. The amino acid concentrations within the xylem sap and phloem exudate derived from these structures were greatest during anthesis and fruit set, and a second peak occurred within the rachis phloem at the onset of ripening. The concentrations of the amino acids within the phloem and xylem sap of the rachis were highest just prior to or after midnight while the flow of sugar through the rachis phloem was greatest during the early afternoon. Sugar exudation rates from the rachis was greater than that of the petiole phloem between anthesis and berry maturity. In summary, amino acid and sugar delivery through the vasculature to grape berries fluctuates over the course of the day as well as through the season and is not necessarily related to levels near the source. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  8. Medium-term response of microbial community to rhizodeposits of white clover and ryegrass and tracing of active processes induced by 13C and 15N labelled exudates

    DEFF Research Database (Denmark)

    Kusliene, Gedrime; Rasmussen, Jim; Kuzyakov, Yakov

    2014-01-01

    and actinomycetes was unaffected by plant species, but pool of Gram-negative and Gram-positive bacteria was greater under white clover at the 10 percent significance level. In the short term, microorganisms more actively utilised fresh exudates (13C-labelled) of ryegrass than of white clover. We expected ryegrass...... microbial groups in soil under white clover (Trifolium repens L.) and ryegrass (Lolium perenne L.) following leaf-labelling with 13C-bicarbonate and 15N-urea. In this way microbial N and 15N and the composition of PLFAs reflect the medium-term (two months) response of microorganisms to rhizodeposits......, whereas the 13C-label of the PLFAs reflects the short-term (one week) utilisation of root exudates following labelling of shoots. In the medium term, microbial biomass N and 15N were greater under the ryegrass, whereas total PLFA was higher under white clover. The relative abundance of fungi...

  9. The miRNAome dynamics during developmental and metabolic reprogramming of tomato root infected with potato cyst nematode.

    Science.gov (United States)

    Koter, Marek D; Święcicka, Magdalena; Matuszkiewicz, Mateusz; Pacak, Andrzej; Derebecka, Natalia; Filipecki, Marcin

    2018-03-01

    Cyst-forming plant-parasitic nematodes are pests threatening many crops. By means of their secretions cyst nematodes induce the developmental and metabolic reprogramming of host cells that lead to the formation of a syncytium, which is the sole food source for growing nematodes. The in depth micro RNA (miRNA) dynamics in the syncytia induced by Globodera rostochiensis in tomato roots was studied. The miRNAomes were obtained from syncytia covering the early and intermediate developmental stages, and were the subject of differential expression analysis. The expression of 1235 miRNAs was monitored. The fold change (log 2 FC) ranged from -7.36 to 8.38, indicating that this transcriptome fraction was very variable. Moreover, we showed that the DE (differentially expressed) miRNAs do not fully overlap between the selected time points, suggesting infection stage specific regulation by miRNA. The correctness of RNA-seq expression profiling was confirmed by qRT-PCR (quantitative Real Time Polymerase Chain Reaction) for seven miRNA species. Down- and up-regulated miRNA species, including their isomiRs, were further used to identify their potential targets. Among them there are a large number of transcription factors linked to different aspects of plant development belonging to gene families, such as APETALA2 (AP2), SQUAMOSA (MADS-box), MYB, GRAS, and AUXIN RESPONSE FACTOR (ARF). The substantial portion of potential target genes belong to the NB-LRR and RLK (RECEPTOR-LIKE KINASE) families, indicating the involvement of miRNA mediated regulation in defense responses. We also collected the evidence for target cleavage in the case of 29 miRNAs using one of three alternative methods: 5' RACE (5' Rapid Amplification of cDNA Ends), a search of tasiRNA within our datasets, and the meta-analysis of tomato degradomes in the GEO (Gene Expression Omnibus) database. Eight target transcripts showed a negative correlation with their respective miRNAs at two or three time points. These

  10. Human impacts on soil carbon dynamics of deep-rooted Amazonian forests and effect of land use change on the carbon cycle in Amazon soils

    Science.gov (United States)

    Nepstad, Daniel; Stone, Thomas; Davidson, Eric; Trumbore, Susan E.

    1992-01-01

    The main objective of these NASA-funded projects is to improve our understanding of land-use impacts on soil carbon dynamics in the Amazon Basin. Soil contains approximately one half of tropical forest carbon stocks, yet the fate of this carbon following forest impoverishment is poorly studied. Our mechanistics approach draws on numerous techniques for measuring soil carbon outputs, inputs, and turnover time in the soils of adjacent forest and pasture ecosystems at our research site in Paragominas, state of Para, Brazil. We are scaling up from this site-specific work by analyzing Basin-wide patterns in rooting depth and rainfall seasonality, the two factors that we believe should explain much of the variation in tropical soil carbons dynamics. In this report, we summarize ongoing measurements at our Paragominas study site, progress in employing new field data to understand soil C dynamics, and some surprising results from our regional, scale-up work.

  11. CYTOLOGICAL FEATURES OF FENSPIRIDE USAGE IN TREATMENT OF CHRONIC EXUDATIVE OTITIS MEDIA

    Directory of Open Access Journals (Sweden)

    O. Yu. Mezentseva

    2012-01-01

    Full Text Available The cytological investigation of exudates, obtained during tympanostomies, showed the predomination of inflammatory-regenerative cytograms types when using Fenspiride (Eurespal in treatment of secretory stage of chronic exudative otitis media. Received data confirm, that treatment with this drug shortens the course of exudative otitis media and contributes to more rapid change from destructive to reparative stage of inflammation, which prevents the development of adhesive process in the middle ear.

  12. CYTOLOGICAL FEATURES OF FENSPIRIDE USAGE IN TREATMENT OF CHRONIC EXUDATIVE OTITIS MEDIA

    OpenAIRE

    O. Yu. Mezentseva; F. N. Zavjyalov; A. A. Vorobjeva; L. P. Popova; M. V. Rodionova

    2012-01-01

    The cytological investigation of exudates, obtained during tympanostomies, showed the predomination of inflammatory-regenerative cytograms types when using Fenspiride (Eurespal) in treatment of secretory stage of chronic exudative otitis media. Received data confirm, that treatment with this drug shortens the course of exudative otitis media and contributes to more rapid change from destructive to reparative stage of inflammation, which prevents the development of adhesive process in the midd...

  13. Metabolomics of meat exudate: Its potential to evaluate beef meat conservation and aging

    International Nuclear Information System (INIS)

    Castejón, David; García-Segura, Juan Manuel; Escudero, Rosa; Herrera, Antonio; Cambero, María Isabel

    2015-01-01

    In this study we analyzed the exudate of beef to evaluate its potential as non invasive sampling for nuclear magnetic resonance (NMR) based metabolomic analysis of meat samples. Exudate, as the natural juice from raw meat, is an easy to obtain matrix that it is usually collected in small amounts in commercial meat packages. Although meat exudate could provide complete and homogeneous metabolic information about the whole meat piece, this sample has been poorly studied. Exudates from 48 beef samples of different breeds, cattle and storage times have been studied by "1H NMR spectroscopy. The liquid exudate spectra were compared with those obtained by High Resolution Magic Angle Spinning (HRMAS) of the original meat pieces. The close correlation found between both spectra (>95% of coincident peaks in both registers; Spearman correlation coefficient = 0.945) lead us to propose the exudate as an excellent alternative analytical matrix with a view to apply meat metabolomics. 60 metabolites could be identified through the analysis of mono and bidimensional exudate spectra, 23 of them for the first time in NMR meat studies. The application of chemometric tools to analyze exudate dataset has revealed significant metabolite variations associated with meat aging. Hence, NMR based metabolomics have made it possible both to classify meat samples according to their storage time through Principal Component Analysis (PCA), and to predict that storage time through Partial Least Squares (PLS) regression. - Highlights: • NMR spectra from beef samples and their exudates are very strongly correlated. • 23 metabolites not reported in previous NMR meat studies have been identified. • Meat exudate NMR spectra allow monitoring of biochemical changes related to aging. • PCA of exudate NMR spectra classified meat samples by their storage time. • The aging of a meat sample can be predicted by PLS analysis of its exudate.

  14. Metabolomics of meat exudate: Its potential to evaluate beef meat conservation and aging

    Energy Technology Data Exchange (ETDEWEB)

    Castejón, David [Centro de Asistencia a la Investigación de Resonancia Magnética Nuclear y de Espín Electrónico, Universidad Complutense de Madrid, 28040 Madrid (Spain); García-Segura, Juan Manuel [Centro de Asistencia a la Investigación de Resonancia Magnética Nuclear y de Espín Electrónico, Universidad Complutense de Madrid, 28040 Madrid (Spain); Departamento de Bioquímica y Biología Molecular I, Facultad de Químicas, Universidad Complutense de Madrid, 28040 Madrid (Spain); Escudero, Rosa [Departamento de Nutrición, Bromatología y Tecnología de los Alimentos, Facultad de Veterinaria. Universidad Complutense de Madrid, 28040 Madrid (Spain); Herrera, Antonio [Departamento de Química Orgánica, Facultad de Químicas, Universidad Complutense de Madrid, 28040 Madrid (Spain); Cambero, María Isabel, E-mail: icambero@vet.ucm.es [Departamento de Nutrición, Bromatología y Tecnología de los Alimentos, Facultad de Veterinaria. Universidad Complutense de Madrid, 28040 Madrid (Spain)

    2015-12-11

    In this study we analyzed the exudate of beef to evaluate its potential as non invasive sampling for nuclear magnetic resonance (NMR) based metabolomic analysis of meat samples. Exudate, as the natural juice from raw meat, is an easy to obtain matrix that it is usually collected in small amounts in commercial meat packages. Although meat exudate could provide complete and homogeneous metabolic information about the whole meat piece, this sample has been poorly studied. Exudates from 48 beef samples of different breeds, cattle and storage times have been studied by {sup 1}H NMR spectroscopy. The liquid exudate spectra were compared with those obtained by High Resolution Magic Angle Spinning (HRMAS) of the original meat pieces. The close correlation found between both spectra (>95% of coincident peaks in both registers; Spearman correlation coefficient = 0.945) lead us to propose the exudate as an excellent alternative analytical matrix with a view to apply meat metabolomics. 60 metabolites could be identified through the analysis of mono and bidimensional exudate spectra, 23 of them for the first time in NMR meat studies. The application of chemometric tools to analyze exudate dataset has revealed significant metabolite variations associated with meat aging. Hence, NMR based metabolomics have made it possible both to classify meat samples according to their storage time through Principal Component Analysis (PCA), and to predict that storage time through Partial Least Squares (PLS) regression. - Highlights: • NMR spectra from beef samples and their exudates are very strongly correlated. • 23 metabolites not reported in previous NMR meat studies have been identified. • Meat exudate NMR spectra allow monitoring of biochemical changes related to aging. • PCA of exudate NMR spectra classified meat samples by their storage time. • The aging of a meat sample can be predicted by PLS analysis of its exudate.

  15. Exudative Retinal Detachment Treatment in a Patient with Thrombotic Thrombocytopenic Purpura

    Directory of Open Access Journals (Sweden)

    Magali Sampo

    2016-02-01

    Full Text Available Purpose: We report a case of unilateral exudative retinal detachment in a patient with thrombotic thrombocytopenic purpura (TTP, without associated hypertension, successfully treated with plasmapheresis. Case Report: A 46-year-old woman with a medical history of TTP presented with unilateral exudative retinal detachment. Biological and radiological assessment eliminated other causes of exudative retinal detachment, including hypertension. Plasma exchange was performed, followed by a rapid improvement in visual acuity and total disappearance of serous detachment. Conclusion: Exudative unilateral retinal detachment is a rare complication of TTP and can be successfully treated by plasma exchange.

  16. Transudative vs exudative pleural effusions: differentiation using Gd-DTPA-enhanced MRI

    International Nuclear Information System (INIS)

    Frola, C.; Cantoni, S.; Turtulici, I.; Leoni, C.; Loria, F.; Gaeta, M.; Derchi, L.E.

    1997-01-01

    The aim of this study was to investigate the capability of Gd-DTPA-enhanced MRI to differentiate between exudative and transudative pleural effusions. An MRI examination was performed on 22 patients with different types of pleural effusion (10 transudative and 12 exudative effusions). T1-weighted SE images were obtained before and 20 min after administration of Gd-DTPA (0.1 mmol/kg). The degree of enhancement of pleural effusions was evaluated both by visual assessement and by quantitative analysis of images. None of 10 transudative effusions showed significative enhancement, whereas 10 of 12 exudative effusions showed enhancement (sensitivity 83 %, specificity 100 %, positive predictive value 100 %). The postcontrast signal intensity ratios (SIRs) of exudates were significantly higher than corresponding precontrast ratios (P = 0.0109) and the postcontrast SIRs of exudates were significantly higher than those of transudates (P = 0.0300). Exudative pleural effusions show a significant enhancement following administration of Gd-DTPA. We presume that this may be caused by increased pleural permeability and more rapid passage of a large amount of Gd-DTPA from the blood into the pleural fluid in case of exudative effusions. In our limited group of patients, signal enhancement proved the presence of an exudative effusion. Absence of signal enhancement suggests a transudate, but does not exclude an exudate. (orig.). With 5 figs., 2 tabs

  17. Exudative epidermitis in pigs caused by toxigenic Staphylococcus chromogenes.

    Science.gov (United States)

    Andresen, Lars Ole; Ahrens, Peter; Daugaard, Lise; Bille-Hansen, Vivi

    2005-02-25

    Staphylococcus chromogenes is closely related to Staphylococcus hyicus, which is recognised as the causative agent of exudative epidermitis (EE) in pigs. S. chromogenes is part of the normal skin flora of pigs, cattle and poultry and has so far been considered non-pathogenic to pigs. A strain of S. chromogenes producing exfoliative toxin type B, ExhB, was identified by the use of a multiplex PCR specific for the exfoliative toxins from S. hyicus. The exfoliative toxin from S. chromogenes reacted in immunoblot analysis with polyclonal and monoclonal antibodies specific to ExhB from S. hyicus and had an apparent molecular weight of 30 kDa. Sequencing the gene encoding the exfoliative toxin from S. chromogenes revealed that the molecular weight of the toxin with the signal peptide and the mature toxin was 30,553 and 26,694 Da, respectively. Comparison of the exhB genes from S. chromogenes strain VA654 and S. hyicus strain 1289D-88 showed differences in seven base pairs of the DNA sequences and in two amino acid residues in the deduced amino acid sequences. Pigs were experimentally inoculated with S. chromogenes strain VA654. By clinical observations and histopathological evaluation of the skin alterations, all pigs revealed development of generalized exudative epidermitis. No toxin producing S. hyicus was isolated from the pigs and all ExhB-positive bacterial isolates were identified as S. chromogenes. This confirmed that the disease-causing agent was the inoculated S. chromogenes strain VA654. The results of this study show that S. chromogenes may cause exudative epidermitis in pigs.

  18. EFFECTS OF ELEVATED CO-2 AND N FERTILIZATION ON FINE ROOT DYNAMICS AND FUNGAL GROWTH IN SEEDLING PINUS PONDEROSA

    Science.gov (United States)

    The effects of elevated CO-2 and N fertilization on fine root growth of Pinus ponderosa Dougl. ex P. Laws. C. Laws., grown in native soil in open-top field-exposure chambers at Placerville, CA, were monitored for a 2-year period using minirhizotrons. The experimental design was a...

  19. Mathematics Teachers' Visualization of Complex Number Multiplication and the Roots of Unity in a Dynamic Geometry Environment

    Science.gov (United States)

    Caglayan, Gunhan

    2016-01-01

    This qualitative research, drawing on the theoretical frameworks by Even (1990, 1993) and Sfard (2007), investigated five high school mathematics teachers' geometric interpretations of complex number multiplication along with the roots of unity. The main finding was that mathematics teachers constructed the modulus, the argument, and the conjugate…

  20. Spatial and temporal dynamics of water in the root environment of potted plants on a flooded bench fertigation system

    NARCIS (Netherlands)

    Otten, W.; Raats, P.A.C.; Baas, R.; Challa, H.; Kabat, P.

    1999-01-01

    The relationship between evapotranspiration of potted Ficus benjamina plants on a flooded bench fertigation system and the distribution of water in the root zone was studied in detail for a range of fertigation schedules. The physical characteristics of the peat-based potting medium were described

  1. PHYTOREMEDIATION: PLANT UPTAKE OF ATRAZINE AND THE ROLE OF ROOT EXUDATES. (R825549C060)

    Science.gov (United States)

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  2. Methods of collection of plant root exudates in relation to plant metabolism and purpose: A review

    Czech Academy of Sciences Publication Activity Database

    Vránová, V.; Rejšek, K.; Skene, K. R.; Janouš, Dalibor; Formanek, P.

    2013-01-01

    Roč. 176, č. 2 (2013), s. 175-199 ISSN 1436-8730 R&D Projects: GA MŠk(CZ) ED1.1.00/02.0073; GA MŠk(CZ) LM2010007 Institutional support: RVO:67179843 Keywords : allelochemical / CAM / C3 * C4 metabolism * retrieval * rhizodeposition * rhizosphere Subject RIV: EH - Ecology, Behaviour Impact factor: 1.663, year: 2013

  3. Amelioration of Pb and Mn toxicity to arbuscular mycorrhizal fungus Glomus intraradices by maize root exudates

    Czech Academy of Sciences Publication Activity Database

    Malcová, Radka; Gryndler, Milan

    2003-01-01

    Roč. 47, č. 2 (2003), s. 297-299 ISSN 0006-3134 R&D Projects: GA AV ČR KSK6005114; GA MŠk OC 838.10 Institutional research plan: CEZ:AV0Z6005908 Keywords : heavy metals * hyphal growth * Zea mays Subject RIV: EF - Botanics Impact factor: 0.919, year: 2003

  4. Ecophysiological characterization of carnivorous plant roots: oxygen fluxes, respiration, and water exudation

    Czech Academy of Sciences Publication Activity Database

    Adamec, Lubomír

    2005-01-01

    Roč. 49, č. 2 (2005), s. 247-255 ISSN 0006-3134 R&D Projects: GA AV ČR(CZ) IAA6005909 Institutional research plan: CEZ:AV0Z6005908 Keywords : terrestrial carnivorous plants * soil anoxia * Genlisea traps Subject RIV: EF - Botanics Impact factor: 0.792, year: 2005

  5. TRANSGENIC PLANTS - INSECTICIDAL TOXIN IN ROOT EXUDATES FROM BT CORN. (R826107)

    Science.gov (United States)

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  6. Root fractures

    DEFF Research Database (Denmark)

    Andreasen, Jens Ove; Christensen, Søren Steno Ahrensburg; Tsilingaridis, Georgios

    2012-01-01

    The purpose of this study was to analyze tooth loss after root fractures and to assess the influence of the type of healing and the location of the root fracture. Furthermore, the actual cause of tooth loss was analyzed....

  7. Yield of abrams needle pleural biopsy in exudative pleural effusion

    International Nuclear Information System (INIS)

    Khan, I.N.; Zaman, M.; Khan, N.; Jadoon, H.; Ahmed, A.

    2009-01-01

    Pleural effusion is the abnormal collection of fluid in the pleural space resulting from excessive fluid production or decreased absorption and it is one of the most common clinical conditions that we come across in pulmonology clinics and in hospitals. The objective of prospective study was to evaluate the diagnostic role of Abrams Needle Biopsy in Exudative Pleural Effusion The study was performed at the Department of Pulmonology, Ayub Teaching Hospital, Abbottabad over a period of 1 year, i.e., January 2008 to December 2008. Sixty-three patients of either sex and all ages with exudative pleural effusion, on whom Abrams Needle Biopsy was performed were included in the study. Minimum of four specimens from each patient were taken and histopathology done. Out of 63 patients, histopathology revealed the cause in 60 (95%) cases. Tuberculosis, malignancy and rheumatoid pleurisy were confirmed in 34, 24, and 2 cases respectively. Specimens of 3 patients did not reveal any result and showed non-specific inflammation and were further investigated accordingly. The diagnostic yield of Biopsy was 95%. Pleural biopsy is still a reliable and valuable investigation in diagnosing pleural effusion, provided that adequate pleural specimen is taken. (author)

  8. A dynamic growth model of vegetative soya bean plants: model structure and behaviour under varying root temperature and nitrogen concentration

    Science.gov (United States)

    Lim, J. T.; Wilkerson, G. G.; Raper, C. D. Jr; Gold, H. J.

    1990-01-01

    A differential equation model of vegetative growth of the soya bean plant (Glycine max (L.) Merrill cv. Ransom') was developed to account for plant growth in a phytotron system under variation of root temperature and nitrogen concentration in nutrient solution. The model was tested by comparing model outputs with data from four different experiments. Model predictions agreed fairly well with measured plant performance over a wide range of root temperatures and over a range of nitrogen concentrations in nutrient solution between 0.5 and 10.0 mmol NO3- in the phytotron environment. Sensitivity analyses revealed that the model was most sensitive to changes in parameters relating to carbohydrate concentration in the plant and nitrogen uptake rate.

  9. Dynamic modelling of energy demand: A guided tour through the jungle of unit roots and co-integration

    Energy Technology Data Exchange (ETDEWEB)

    Engsted, T; Bentzen, J

    1997-04-01

    This paper provides a detailed survey of the recent literature on unit roots and co-integration, and relates the concepts to the estimation of energy demand relationships. The special features and properties of non-stationary time-series are discussed, including the relevant asymptotic theory. The most often used tests for unit roots and co-integration - and various techniques for estimating co-integration relationships - are described, and the connection between co-integration and error-correction models is explored. Further, we revisit the autoregressive distributed lag (ADL) model, which is very often used in energy demand studies, and state under which conditions this model provides a valid framework for estimating income- and price- elasticities, when time-series are non-stationary. Throughout, tests and estimation techniques are illustrated using data on Danish energy consumption, prices, income, and temperature. (au) 71 refs.

  10. Enhancement of phloem exudation from Fraxinus uhdei Wenz. (evergreen ash) using ethylenediaminetetraacetic acid

    International Nuclear Information System (INIS)

    Costello, L.R.; Bassham, J.A.; Calvin, M.

    1982-01-01

    Ethylenediaminetetraacetic acid (EDTA) enhanced the exudation of 14 C-labeled assimilates from excised leaflets and whole plant specimens of Fraxinus uhdei Wenz. A 2 millimolar EDTA concentration was found to be most effective in promoting exudation from excised leaflets, while 10 millimolar EDTA was most effective in whole plants experiments. Exudation rate reached a maximum after 24 hours in both experiments. The continuous presence of EDTA throughout the treatment period was required for maximum exudation from excised leaflets. Stachyose, raffinose, verbascose, and sucrose were the principal compounds found to occur in exudate samples. These compounds are typically transported in sieve elements of various Fraxinus species suggesting the exudate was of phloem orgin. Electron microscope studies of petiolule sieve plate pores from excisd leaflets showed substantially less callose appearing after treatment with EDTA than after H 2 O treatment. It is suggested that EDTA enhances phloem exudation by inhibiting or reducing callose formation in sieve plate pores. The exudation enhancement technique described for whole plant specimens is suggested as a useful means of collecting phloem sap and studying translocation in woody plants

  11. intra-species variation of the properties of gum exudates from Acacia

    African Journals Online (AJOL)

    a

    The results show that significant inter-species variation of the properties of the gum exudates from the two species exist, whereas only some parameters show significant intra-species variation. The specific optical rotations of the gum exudates have been found to vary from ---43.2o to ---52o for Acacia senegal var. senegal ...

  12. Phytotoxic grass residues reduce germination and initial root growth of ponderosa pine

    Science.gov (United States)

    W. J. Rietveld

    1975-01-01

    Extracts of green foliage of Arizona fescue and mountain muhly significantly reduced germination of ponderosa pine seeds, and retarded speed of elongation and mean radicle length. Three possible routes of release of the inhibitor were investigated: (1) leaching from live foliage, (2) root exudation, and (3) overwinter leaching from dead residues. The principal route...

  13. Physicochemical and functional parameters of Cochlospermum vitifolium (bototo gum exudate

    Directory of Open Access Journals (Sweden)

    Maritza Coromoto Martínez

    2016-12-01

    Full Text Available The physicochemical parameters of Cochlospermum vitifolium they were evaluated and were linked to certain functional properties of industrial interest. The physicochemical parameters were determined by the classic methodology used for carbohydrates and the functional properties, as reported in the literature. The results obtained showed that the gum object of this study is low soluble in water, which corresponds with relatively high values of swelling indexes and water absorption capacity. Also, the intrinsic viscosity of the C. vitifolium exudate was related to a high molar mass, in the order of 106. Its emulsifying capacity is high, which is attributed to hydrophobic groups present in its structure. The gum gels at a minimum concentration, similar to that of the gum karaya (4.5%, but the gel that forms agglomerates, it is not uniform. The C. vitifolium gum exhibits important physicochemical and functional parameters which could serve as a criterion for testing its use in various industries.

  14. Oxidation of cashew tree gum exudate polysaccharide with TEMPO reagent

    Energy Technology Data Exchange (ETDEWEB)

    Cunha, Pablyana L.R.; Maciel, Jeanny S.; Paula, Regina C.M. de; Feitosa, Judith P.A. [Universidade Federal do Ceara, Fortaleza, CE (Brazil). Dept. de Quimica Organica e Inorganica; Sierakowski, Maria Rita [Universidade Federal do Parana, Curitiba, PR (Brazil). Dept. de Quimica]. E-mail: judith@dqoi.ufc.br

    2007-07-01

    Cashew gum (CG), an exudate polysaccharide from Anacardium occidentale trees, was oxidized with TEMPO reagent and the product (CGOX) characterized by spectroscopic techniques (FTIR and NMR), chromatographic analyses (HPLC and GPC), viscosity measurements and thermal analysis (TGA). The yield of the reaction product was 96%. The uronic acid content in starting gum (7.2 m%) was increased to 36 m%. The degree of oxidation based on free galactose and glucose units was 68%. NMR data show that oxidation occurred preferentially at primary carbons of galactose units. High degradation degree after oxidation was estimated by the difference on the expected and observed {eta}{sub CGOX}/{eta}{sub CG} ratio. The presence of organic and inorganic impurities in the new polyelectrolyte was detected by TGA. A less thermally stable cashew gum is formed after the oxidation with TEMPO based on initial decomposition temperature and IPDT. (author)

  15. Exudative epidermitis in pigs caused by toxigenic Staphylococcus chromogenes

    DEFF Research Database (Denmark)

    Andresen, Lars Ole; Ahrens, Peter; Daugaard, Lise

    2005-01-01

    Staphylococcus chromogenes is closely related to Staphylococcus hyicus, which is recognised as the causative agent of exudative epidermitis (EE) in pigs. S. chromogenes is part of the normal skin flora of pigs, cattle and poultry and has so far been considered non-pathogenic to pigs. A strain of S....... chromogenes producing exfoliative toxin type B, ExhB, was identified by the use of a multiplex PCR specific for the exfoliative toxins from S. hyicus. The exfoliative toxin from S. chromogenes reacted in immunoblot analysis with polyclonal and monoclonal antibodies specific to ExhB from S. hyicus and had...... an apparent molecular weight of 30 kDa. Sequencing the gene encoding the exfoliative toxin from S. chromogenes revealed that the molecular weight of the toxin with the signal peptide and the mature toxin was 30,553 and 26,694 Da, respectively. Comparison of the exhB genes from S. chromogenes strain VA654...

  16. Oxidation of cashew tree gum exudate polysaccharide with TEMPO reagent

    International Nuclear Information System (INIS)

    Cunha, Pablyana L.R.; Maciel, Jeanny S.; Paula, Regina C.M. de; Feitosa, Judith P.A.; Sierakowski, Maria Rita

    2007-01-01

    Cashew gum (CG), an exudate polysaccharide from Anacardium occidentale trees, was oxidized with TEMPO reagent and the product (CGOX) characterized by spectroscopic techniques (FTIR and NMR), chromatographic analyses (HPLC and GPC), viscosity measurements and thermal analysis (TGA). The yield of the reaction product was 96%. The uronic acid content in starting gum (7.2 m%) was increased to 36 m%. The degree of oxidation based on free galactose and glucose units was 68%. NMR data show that oxidation occurred preferentially at primary carbons of galactose units. High degradation degree after oxidation was estimated by the difference on the expected and observed η CGOX /η CG ratio. The presence of organic and inorganic impurities in the new polyelectrolyte was detected by TGA. A less thermally stable cashew gum is formed after the oxidation with TEMPO based on initial decomposition temperature and IPDT. (author)

  17. X linked exudative vitreoretinopathy: clinical features and genetic linkage analysis.

    Science.gov (United States)

    Fullwood, P; Jones, J; Bundey, S; Dudgeon, J; Fielder, A R; Kilpatrick, M W

    1993-03-01

    A four generation family in which familial exudative vitreoretinopathy is inherited as an X linked condition is described. Essentially the condition is one of abnormal vascularisation and signs at birth are those of a retinopathy superficially resembling retinopathy of prematurity, retinal folds, or, in advanced cases, enophthalmos or even phthisis. Prognosis depends on the progression of the retinal changes. The family members, including seven affected males and five obligate carrier females, have been types for 20 DNA markers, and linkage analysis suggests a gene locus either at Xq21.3 or at Xp11. As the latter region includes the locus for the gene for Norrie disease, it is possible that this and X linked vitreoretinopathy are allelic. We can further speculate that the differences in severity of the clinical manifestations are dependent only upon the timing of the insult.

  18. Proton-transfer-reaction mass spectrometry as a new tool for real time analysis of root-secreted volatile organic compounds in arabidopsis

    NARCIS (Netherlands)

    Steeghs, M.M.L.; Bais, H.P.; de Gouw, J.; Goldan, P.; Kuster, W.; Northway, M.; Fall, R.; Vivanco, J.M.

    2004-01-01

    Plant roots release about 5% to 20% of all photosynthetically-fixed carbon, and as a result create a carbon-rich environment for numerous rhizosphere organisms, including plant pathogens and symbiotic microbes. Although some characterization of root exudates has been achieved, especially of

  19. Dynamic Torque and Vertical Force Analysis during Nickel-titanium Rotary Root Canal Preparation with Different Modes of Reciprocal Rotation.

    Science.gov (United States)

    Tokita, Daisuke; Ebihara, Arata; Nishijo, Miki; Miyara, Kana; Okiji, Takashi

    2017-10-01

    The purpose of the present study was to compare 2 modes of reciprocal movement (torque-sensitive and time-dependent reciprocal rotation) with continuous rotation in terms of torque and apical force generation during nickel-titanium rotary root canal instrumentation. A custom-made automated root canal instrumentation and torque/force analyzing device was used to prepare simulated canals in resin blocks and monitor the torque and apical force generated in the blocks during preparation. Experimental groups (n = 7, each) consisted of (1) torque-sensitive reciprocal rotation with torque-sensitive vertical movement (group TqR), (2) time-dependent reciprocal rotation with time-dependent vertical movement (group TmR), and (3) continuous rotation with time-dependent vertical movement (group CR). The canals were instrumented with TF Adaptive SM1 and SM2 rotary files (SybronEndo, Orange, CA), and the torque and apical force were measured during instrumentation with SM2. The mean and maximum torque and apical force values were statistically analyzed using 1-way analysis of variance and the Tukey test (α = 0.05). The recordings showed intermittent increases of upward apical force and clockwise torque, indicating the generation and release of screw-in forces. The maximum upward apical force values in group TmR were significantly smaller than those in group CR (P forces when compared with continuous rotation. Copyright © 2017 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  20. Linking development and determinacy with organic acid efflux from proteoid roots of white lupin grown with low phosphorus and ambient or elevated atmospheric CO{sub 2} concentration

    Energy Technology Data Exchange (ETDEWEB)

    Watt, M.; Evans, J.R.

    1999-07-01

    White lupin (Lupinus albus L.) was grown in hydroponic culture with 1 {micro}M phosphorus to enable the development of proteoid roots to be observed in conjunction with organic acid exudation. Discrete regions of closely spaced, determinate secondary laterals emerged in near synchrony on the same plant. One day after reaching their final length, citrate exudation occurred over a 3-d pulse. The rate of exudation varied diurnally, with maximal rates during the photoperiod. At the onset of citrate efflux, rootlets had exhausted their apical meristems and had differentiated root hairs and vascular tissues along their lengths. Neither in vitro phosphoenolpyruvate carboxylase nor citrate synthase activity was correlated with the rate of citrate exudation. The authors suggest that an unidentified transport process, presumably at the plasma membrane, regulates citrate efflux. Growth with elevated atmospheric [CO{sub 2}] promoted earlier onset of rootlet determinacy by 1 d, resulting in shorter rootlets and citrate export beginning 1 d earlier as a 2-d diurnal pulse. Citrate was the dominant organic acid exported, and neither the rate of exudation per unit length of root nor the composition of exudate was altered by atmospheric [CO{sub 2}].

  1. Roots & Hollers

    OpenAIRE

    Kollman, Patrick L; Gorman, Thomas A

    2011-01-01

    Roots & Hollers, 2011 A documentary by Thomas Gorman & Patrick Kollman Master’s Project Abstract: Roots & Hollers uncovers the wild American ginseng trade, revealing a unique intersection between Asia and rural America. Legendary in Asia for its healing powers, ginseng helps sustain the livelihoods of thousands in Appalachia. A single root can sell for thousands of dollars at auction. Shot on-location in the mountains of Kentucky and West Virginia, this student doc...

  2. Missing links in the root-soil organic matter continuum

    Energy Technology Data Exchange (ETDEWEB)

    O' Brien, Sarah L. [Argonne National Laboratory (ANL); Iversen, Colleen M [ORNL

    2009-01-01

    wide range of soil processes, from the exudation of labile C compounds to the development of fungal associations. For example, Zoe Cardon demonstrated that the root-mediated redistribution of deep soil water to relatively dry shallower soil, increased soil CO{sub 2} efflux and nutrient cycling near the surface in an arid ecosystem. Andrew Kulmatiski also discussed the importance of rooting distribution throughout the soil profile for strategies of water uptake by different species in an African savanna. Later, Julie Jastrow demonstrated that living roots shape soil physical structure by promoting the formation of soil aggregates, which facilitated accrual of SOM in restored grasslands. Taken together, the evidence is compelling that living roots, and organic matter derived from root detritus, are important parts of the continuum of organic matter in the soil. Larger soil organisms (i.e. 50 {micro}m to many cm in body size) play an important role in the root-SOM continuum by grazing on roots and microbes, comminuting organic matter and aggregating soil in fecal pellets. However, litterbag and soil incubation studies necessarily exclude invertebrates, and research on faunal activity and trophic dynamics tends to be independent from research on the biogeochemistry of SOM cycling. Tim Filley used plant-derived biomarkers in invertebrate residues to bridge the gap between larger soil organisms, such as earthworms and beetle larvae, and SOM distribution. He found that larger soil organisms help to stabilize root-derived organic matter in soil aggregates. Similar coupling of biogeochemistry with food web studies could prove fruitful for describing mechanisms that underlie critical ecosystem processes. Despite considerable research efforts, the breadth of the microbial role in the root-SOM continuum remains unresolved. Using advanced pyrosequencing techniques, David Nelson demonstrated the importance of archea as nitrifiers in agricultural systems exposed to elevated [CO{sub 2

  3. Osmotic stress represses strigolactone biosynthesis in Lotus japonicus roots: exploring the interaction between strigolactones and ABA under abiotic stress

    KAUST Repository

    Liu, Junwei

    2015-02-26

    Main conclusion: Strigolactone changes and cross talk with ABA unveil a picture of root-specific hormonal dynamics under stress.Abstract: Strigolactones (SLs) are carotenoid-derived hormones influencing diverse aspects of development and communication with (micro)organisms, and proposed as mediators of environmental stimuli in resource allocation processes; to contribute to adaptive adjustments, therefore, their pathway must be responsive to environmental cues. To investigate the relationship between SLs and abiotic stress in Lotus japonicus, we compared wild-type and SL-depleted plants, and studied SL metabolism in roots stressed osmotically and/or phosphate starved. SL-depleted plants showed increased stomatal conductance, both under normal and stress conditions, and impaired resistance to drought associated with slower stomatal closure in response to abscisic acid (ABA). This confirms that SLs contribute to drought resistance in species other than Arabidopsis. However, we also observed that osmotic stress rapidly and strongly decreased SL concentration in tissues and exudates of wild-type Lotus roots, by acting on the transcription of biosynthetic and transporter-encoding genes and independently of phosphate abundance. Pre-treatment with exogenous SLs inhibited the osmotic stress-induced ABA increase in wild-type roots and down-regulated the transcription of the ABA biosynthetic gene LjNCED2. We propose that a transcriptionally regulated, early SL decrease under osmotic stress is needed (but not sufficient) to allow the physiological increase of ABA in roots. This work shows that SL metabolism and effects on ABA are seemingly opposite in roots and shoots under stress.

  4. Osmotic stress represses strigolactone biosynthesis in Lotus japonicus roots: exploring the interaction between strigolactones and ABA under abiotic stress

    KAUST Repository

    Liu, Junwei; He, Hanzi; Vitali, Marco; Visentin, Ivan; Charnikhova, Tatsiana V.; Haider, Imran; Schubert, Andrea; Ruyter-Spira, Carolien P.; Bouwmeester, Harro J J; Lovisolo, Claudio; Cardinale, Francesca

    2015-01-01

    Main conclusion: Strigolactone changes and cross talk with ABA unveil a picture of root-specific hormonal dynamics under stress.Abstract: Strigolactones (SLs) are carotenoid-derived hormones influencing diverse aspects of development and communication with (micro)organisms, and proposed as mediators of environmental stimuli in resource allocation processes; to contribute to adaptive adjustments, therefore, their pathway must be responsive to environmental cues. To investigate the relationship between SLs and abiotic stress in Lotus japonicus, we compared wild-type and SL-depleted plants, and studied SL metabolism in roots stressed osmotically and/or phosphate starved. SL-depleted plants showed increased stomatal conductance, both under normal and stress conditions, and impaired resistance to drought associated with slower stomatal closure in response to abscisic acid (ABA). This confirms that SLs contribute to drought resistance in species other than Arabidopsis. However, we also observed that osmotic stress rapidly and strongly decreased SL concentration in tissues and exudates of wild-type Lotus roots, by acting on the transcription of biosynthetic and transporter-encoding genes and independently of phosphate abundance. Pre-treatment with exogenous SLs inhibited the osmotic stress-induced ABA increase in wild-type roots and down-regulated the transcription of the ABA biosynthetic gene LjNCED2. We propose that a transcriptionally regulated, early SL decrease under osmotic stress is needed (but not sufficient) to allow the physiological increase of ABA in roots. This work shows that SL metabolism and effects on ABA are seemingly opposite in roots and shoots under stress.

  5. A Stable-Isotope Mass Spectrometry-Based Metabolic Footprinting Approach to Analyze Exudates from Phytoplankton

    Directory of Open Access Journals (Sweden)

    Mark R. Viant

    2013-10-01

    Full Text Available Phytoplankton exudates play an important role in pelagic ecology and biogeochemical cycles of elements. Exuded compounds fuel the microbial food web and often encompass bioactive secondary metabolites like sex pheromones, allelochemicals, antibiotics, or feeding attractants that mediate biological interactions. Despite this importance, little is known about the bioactive compounds present in phytoplankton exudates. We report a stable-isotope metabolic footprinting method to characterise exudates from aquatic autotrophs. Exudates from 13C-enriched alga were concentrated by solid phase extraction and analysed by high-resolution Fourier transform ion cyclotron resonance mass spectrometry. We used the harmful algal bloom forming dinoflagellate Alexandrium tamarense to prove the method. An algorithm was developed to automatically pinpoint just those metabolites with highly 13C-enriched isotope signatures, allowing us to discover algal exudates from the complex seawater background. The stable-isotope pattern (SIP of the detected metabolites then allowed for more accurate assignment to an empirical formula, a critical first step in their identification. This automated workflow provides an effective way to explore the chemical nature of the solutes exuded from phytoplankton cells and will facilitate the discovery of novel dissolved bioactive compounds.

  6. Automatic detection of retinal exudates in fundus images of diabetic retinopathy patients

    Directory of Open Access Journals (Sweden)

    Mahsa Partovi

    2016-05-01

    Full Text Available Introduction: Diabetic retinopathy (DR is the most frequent microvascular complication of diabetes and can lead to several retinal abnormalities including microaneurysms, exudates, dot and blot hemorrhages, and cotton wool spots. Automated early detection of these abnormalities could limit the severity of the disease and assist ophthalmologists in investigating and treating the disease more efficiently. Segmentation of retinal image features provides the basis for automated assessment. In this study, exudates lesion on retinopathy retinal images was segmented by different image processing techniques. The objective of this study is detection of the exudates regions on retinal images of retinopathy patients by different image processing techniques. Methods: A total of 30 color images from retinopathy patients were selected for this study. The images were taken by Topcon TRC-50 IX mydriatic camera and saves with TIFF format with a resolution of 500 × 752 pixels. The morphological function was applied on intensity components of hue saturation intensity (HSI space. To detect the exudates regions, thresholding was performed on all images and the exudates region was segmented. To optimize the detection efficiency, the binary morphological functions were applied. Finally, the exudates regions were quantified and evaluated for further statistical purposes. Results: The average of sensitivity of 76%, specificity of 98%, and accuracy of 97% was obtained. Conclusion: The results showed that our approach can identify the exudate regions in retinopathy images.

  7. Rhizosphere microbial community structure in relation to root location and plant iron nutritional status.

    Science.gov (United States)

    Yang, C H; Crowley, D E

    2000-01-01

    Root exudate composition and quantity vary in relation to plant nutritional status, but the impact of the differences on rhizosphere microbial communities is not known. To examine this question, we performed an experiment with barley (Hordeum vulgare) plants under iron-limiting and iron-sufficient growth conditions. Plants were grown in an iron-limiting soil in root box microcosms. One-half of the plants were treated with foliar iron every day to inhibit phytosiderophore production and to alter root exudate composition. After 30 days, the bacterial communities associated with different root zones, including the primary root tips, nonelongating secondary root tips, sites of lateral root emergence, and older roots distal from the tip, were characterized by using 16S ribosomal DNA (rDNA) fingerprints generated by PCR-denaturing gradient gel electrophoresis (DGGE). Our results showed that the microbial communities associated with the different root locations produced many common 16S rDNA bands but that the communities could be distinguished by using correspondence analysis. Approximately 40% of the variation between communities could be attributed to plant iron nutritional status. A sequence analysis of clones generated from a single 16S rDNA band obtained at all of the root locations revealed that there were taxonomically different species in the same band, suggesting that the resolving power of DGGE for characterization of community structure at the species level is limited. Our results suggest that the bacterial communities in the rhizosphere are substantially different in different root zones and that a rhizosphere community may be altered by changes in root exudate composition caused by changes in plant iron nutritional status.

  8. Impact of Roots and Rhizomes on Wetland Archaeology: a review

    DEFF Research Database (Denmark)

    Tjellden, Anna Katarina Ejgreen; Kristiansen, Søren Munch; Matthiesen, Henning

    2015-01-01

    species that can damage site stratigraphy and artefacts. However, reviews on the types and degree of damage caused by vegetation to archaeological remains preserved in situ in wetlands have hitherto only been sporadically treated in the literature. Thus, this paper provides an overview of the adverse...... be spatially and temporally concomitant. In waterlogged anoxic environments, deterioration is mainly related to (i) preferential growth of roots/rhizomes due to nutrient uptake and lesser soil resistance, (ii) root etching due to organic acid exudates, (iii) microbial growth due to root release of oxygen...... and labile organic compounds, and/or (iv) precipitation of hydroxides due to root release of oxygen. For example, roots of some wetland plants, such as marsh horsetail (Equisetum palustre), have been documented to penetrate archaeological artefacts down to c. 2 m in waterlogged anoxic soils. Here, we...

  9. Optical sensor nanoparticles in artificial sediments--a new tool to visualize O2 dynamics around the rhizome and roots of seagrasses.

    Science.gov (United States)

    Koren, Klaus; Brodersen, Kasper E; Jakobsen, Sofie L; Kühl, Michael

    2015-02-17

    Seagrass communities provide important ecosystems services in coastal environments but are threatened by anthropogenic impacts. Especially the ability of seagrasses to aerate their below-ground tissue and immediate rhizosphere to prevent sulfide intrusion from the surrounding sediment is critical for their resilience to environmental disturbance. There is a need for chemical techniques that can map the O2 distribution and dynamics in the seagrass rhizosphere upon environmental changes and thereby identify critical stress thresholds of e.g. water flow, turbidity, and O2 conditions in the water phase. In a novel experimental approach, we incorporated optical O2 sensor nanoparticles into a transparent artificial sediment matrix consisting of pH-buffered deoxygenated sulfidic agar. Seagrass growth and photosynthesis was not inhibited in the experimental setup when the below-ground biomass was immobilized in the artificial sulfidic sediment with nanoparticles and showed root growth rates (∼ 5 mm day(-1)) and photosynthetic quantum yields (∼ 0.7) comparable to healthy seagrasses in their natural habitat. We mapped the real-time below ground O2 distribution and dynamics in the whole seagrass rhizosphere during experimental manipulation of light exposure and O2 content in the overlaying water. Those manipulations showed that oxygen release from the belowground tissue is much higher in light as compared to darkness and that water column hypoxia leads to diminished oxygen levels around the rhizome/roots. Oxygen release was visualized and analyzed on a whole rhizosphere level, which is a substantial improvement to existing methods relying on point measurements with O2 microsensors or partial mapping of the rhizosphere in close contact with a planar O2 optode. The combined use of optical nanoparticle-based sensors with artificial sediments enables imaging of chemical microenvironments in the rhizosphere of aquatic plants at high spatiotemporal resolution with a relatively

  10. Root patterning

    NARCIS (Netherlands)

    Scheres, Ben; Laskowski, Marta

    2016-01-01

    The mechanisms that pattern lateral root primordial are essential for the elaboration of root system architecture, a trait of key importance for future crop breeding. But which are most important: periodic or local cues? In this issue of Journal of Experimental Botany (pages 1411-1420), Kircher

  11. Rooted Rights Systems in Turbulent Water: The Dynamics of Collective Fishing Rights in La Albufera, Valencia, Spain

    NARCIS (Netherlands)

    Boelens, R.A.; Claudin, V.

    2015-01-01

    Valencia's Albufera Lake is a wetlands area where different sociolegal systems interact. Its El Palmar community is governed by customary laws for fishing and territorial control. These exist alongside, yet in tension with, governmental laws. This article examines the dynamics of fishing rights,

  12. Rooted rights systems in turbulent waters: the dynamics of collective fishing rights in La Albufera, Valencia, Spain

    NARCIS (Netherlands)

    Boelens, R.; Claudin, V.

    2015-01-01

    Valencia's Albufera Lake is a wetlands area where different sociolegal systems interact. Its El Palmar community is governed by customary laws for fishing and territorial control. These exist alongside, yet in tension with, governmental laws. This article examines the dynamics of fishing rights,

  13. Hairy roots of Helianthus annuus: a model system to study phytoremediation of tetracycline and oxytetracycline.

    Science.gov (United States)

    Gujarathi, Ninad P; Haney, Bryan J; Park, Heidi J; Wickramasinghe, S Ranil; Linden, James C

    2005-01-01

    The release of antibiotics to the environment has to be controlled because of serious threats to human health. Hairy root cultures of Helianthus annuus (sunflower), along with their inherent rhizospheric activity, provide a fast growing, microbe-free environment for understanding plant-pollutant interactions. The root system catalyzes rapid disappearance of tetracycline (TC) and oxytetracycline (OTC) from aqueous media, which suggests roots have potential for phytoremediation of the two antibiotics in vivo. In addition, in vitro modifications of the two antibiotics by filtered, cell- and microbe-free root exudates suggest involvement of root-secreted compounds. The modification is confirmed from changes observed in UV spectra of exudate-treated OTC. Modification appears to be more dominant at the BCD chromophore of the antibiotic molecule. Kinetic analyses dismiss direct enzyme catalysis; the modification rates decrease with increasing OTC concentrations. The rates increase with increasing age of cultures from which root exudates are prepared. The decrease in modification rates upon addition of the antioxidant ascorbic acid (AA) suggests involvement of reactive oxygen species (ROS) in the antibiotic modification process.

  14. Root-secreted allelochemical in the noxious weed Phragmites australis deploys a reactive oxygen species response and microtubule assembly disruption to execute rhizotoxicity.

    Science.gov (United States)

    Rudrappa, Thimmaraju; Bonsall, Justin; Gallagher, John L; Seliskar, Denise M; Bais, Harsh P

    2007-10-01

    Phragmites australis is considered the most invasive plant in marsh and wetland communities in the eastern United States. Although allelopathy has been considered as a possible displacing mechanism in P. australis, there has been minimal success in characterizing the responsible allelochemical. We tested the occurrence of root-derived allelopathy in the invasiveness of P. australis. To this end, root exudates of two P. australis genotypes, BB (native) and P38 (an exotic) were tested for phytotoxicity on different plant species. The treatment of the susceptible plants with P. australis root exudates resulted in acute rhizotoxicity. It is interesting to note that the root exudates of P38 were more effective in causing root death in susceptible plants compared to the native BB exudates. The active ingredient in the P. australis exudates was identified as 3,4,5-trihydroxybenzoic acid (gallic acid). We tested the phytotoxic efficacy of gallic acid on various plant systems, including the model plant Arabidopsis thaliana. Most tested plants succumbed to the gallic acid treatment with the exception of P. australis itself. Mechanistically, gallic acid treatment generated elevated levels of reactive oxygen species (ROS) in the treated plant roots. Furthermore, the triggered ROS mediated the disruption of the root architecture of the susceptible plants by damaging the microtubule assembly. The study also highlights the persistence of the exuded gallic acid in P. australis's rhizosphere and its inhibitory effects against A. thaliana in the soil. In addition, gallic acid demonstrated an inhibitory effect on Spartina alterniflora, one of the salt marsh species it successfully invades.

  15. The spatial and temporal dynamic of algal biomass associated with mangrove roots in Buenaventura bay pacific coast of Colombia

    International Nuclear Information System (INIS)

    Pena Salamanca, Enrique Javier

    2008-01-01

    The spatial and temporal variation of biomass of mangrove associated macro algae growing on roots of Rhizophora mangle and pneumatophores of Avicennia. germinans were studied at three sampling stations in Buenaventura bay, Colombia, between November 1999 and September 2003. Eighteen species of algae were collected including nine Rhodophyceae, five Chlorophyceae and four Cyanophyta (Cyanobacteria). Four species dominated the algal flora and collectively contributed with 90 % of the total algal biomass. Bostrychia calliptera was the most dominant with 32 % of the total biomass, followed by Boodleopsis verticillata (26 %), Catenella impudica (18 %), and Caloglossa leprieurii (12 %) Algal biomass between seasons showed significant differences, with higher biomass found during the dry season compared to those of the rainy season. The algal biomass at the mouth of the estuary was significantly higher than that found in the inner areas of the estuary (annual means of 30.7 ± 10.8 vs. 13.8 ± 4.1 g m 2 respectively).Three well-defined vertical zones were observed, based on algal biomass

  16. Genetic ablation of root cap cells in Arabidopsis

    OpenAIRE

    Tsugeki, Ryuji; Fedoroff, Nina V.

    1999-01-01

    The root cap is increasingly appreciated as a complex and dynamic plant organ. Root caps sense and transmit environmental signals, synthesize and secrete small molecules and macromolecules, and in some species shed metabolically active cells. However, it is not known whether root caps are essential for normal shoot and root development. We report the identification of a root cap-specific promoter and describe its use to genetically ablate root caps by directing root cap-specific expression of...

  17. Concurrent synthesis and release of nod-gene-inducing flavonoids from alfalfa roots

    International Nuclear Information System (INIS)

    Maxwell, C.A.; Phillips, D.A.

    1990-01-01

    Flavonoid signals from alfalfa (Medicago sativa L.) induce transcription of nodulation (nod) genes in Rhizobium meliloti. Alfalfa roots release three major nod-gene inducers: 4',7-dihydroxyflavanone, 4',7-dihydroxyflavone, and 4,4'-dihydroxy-2'-methoxychalcone. The objective of the present study was to define temporal relationships between synthesis and exudation for those flavonoids. Requirements for concurrent flavonoid biosynthesis were assessed by treating roots of intact alfalfa seedlings with [U- 14 C]-L-phenylalanine in the presence or absence of the phenylalanine ammonia-lyase inhibitor L-2-aminoxy-3-phenylpropionic acid (AOPP). In the absence of AOPP, each of the three flavonoids in exudates contained 14 C. In the presence of AOPP, 14 C labeling and release of all the exuded nod-gene inducers were reduced significantly. AOPP inhibited labeling and release of the strongest nod-gene inducer, methoxychalcone, by more than 90%. The release process responsible for exudation of nod-gene inducers appears to be specific rather than a general phenomenon such as a sloughing off of cells during root growth

  18. EXPERIENCE OF TREATMENT WITH FENSPIRIDE IN CHILDREN WITH CHRONIC EXUDATIVE OTITIS MEDIA AFTER TYMPANOSTOMY

    Directory of Open Access Journals (Sweden)

    L.A. Toropova

    2009-01-01

    Full Text Available The trial presents the analysis of factors predisposing to exudative otitis media development in 709 children, needing regular audiologist’s check-up. It was shown that dominating risk factor of auditory tube’s function disorders is hypertrophy of palatine tonsil (it was detected in 69% of children. Besides, doctors from children’s out-patient clinics often use conservative treatment in children with chronic exudative otitis media. Analysis of data obtained at the time of treatment of 180 hospitalized children under the age 1–17 years old with exudative otitis media showed that combination of tympanostomy with fenspiride (Erespal allows achieving of more significant decrease (1.3 times low audibility threshold of different oscillations than in children from control (treated without fenspiride.Key words: children, exudative otitis media, timpanostomy, fenspiride.(Voprosy sovremennoi pediatrii — Current Pediatrics. 2009;8(4:102-105

  19. Comparative Analysis of Automatic Exudate Detection between Machine Learning and Traditional Approaches

    Science.gov (United States)

    Sopharak, Akara; Uyyanonvara, Bunyarit; Barman, Sarah; Williamson, Thomas

    To prevent blindness from diabetic retinopathy, periodic screening and early diagnosis are neccessary. Due to lack of expert ophthalmologists in rural area, automated early exudate (one of visible sign of diabetic retinopathy) detection could help to reduce the number of blindness in diabetic patients. Traditional automatic exudate detection methods are based on specific parameter configuration, while the machine learning approaches which seems more flexible may be computationally high cost. A comparative analysis of traditional and machine learning of exudates detection, namely, mathematical morphology, fuzzy c-means clustering, naive Bayesian classifier, Support Vector Machine and Nearest Neighbor classifier are presented. Detected exudates are validated with expert ophthalmologists' hand-drawn ground-truths. The sensitivity, specificity, precision, accuracy and time complexity of each method are also compared.

  20. Effects of cadmium amendments on low-molecular-weight organic acid exudates in rhizosphere soils of tobacco and sunflower.

    Science.gov (United States)

    Chiang, Po-Neng; Wang, Ming Kuang; Chiu, Chih Yu; Chou, Shu-Yen

    2006-10-01

    To recognize physiological response of plants to cadmium (Cd) toxicity in rhizosphere of plants, the pot experiments were employed to investigate how low-molecular-weight organic acids (LMWOAs) were exudated from tobacco and sunflower roots of Cd-amended soils. The aims of this study were to assess the effect of LMWOAs on uptake of Cd by tobacco and sunflower under pot experiments, thus comparing the ability of tobacco and sunflower for phytoremediation. Surface soils (0-20 cm) were collected from Taichung Experiment Station (TC) (silty loam). Cadmium chloride (CdCl(2)) was amended into TC soil, giving Cd concentrations of 1, 5, 10 mg kg(-1) soil. Soils with different concentrations of Cd were put into 12 cm (i.d.) pots for incubation, and then 2-week-old tobacco and sunflower seedlings were transplanted into the pots. Tobacco and sunflower were grown in greenhouse for 50 days, respectively. The rhizosphere and bulk soils, and fresh plant tissues were collected after harvest. The Cd concentrations in the plant and transfer factor values in the sunflower were higher than that in the tobacco. No LMWOAs were detected by gas chromatograph in bulk soils, and low amounts of LMWOAs were found in uncontaminated rhizosphere soils. Acetic, lactic, glycolic, malic, maleic, and succinic acids were found in the tobacco and sunflower rhizosphere soils. Concentrations of LMWOAs increased with increasing amendment of Cd concentrations in tobacco and sunflower rhizosphere soils. Correlation coefficient (r) of concentrations of Cd amendment versus LMWOAs exudates of tobacco and sunflower were 0.85 and 0.98, respectively. These results suggest that the different levels of LMWOAs present in the rhizosphere soil play an important role in the solubilization of Cd that bound with soil particle into soil solution and then uptake by plants.

  1. Influence of Spirulina platensis exudates on the endocrine and nervous systems of a mammalian model

    OpenAIRE

    Samah M.M. Fathy; Ashraf M.M. Essa

    2015-01-01

    Objective: To investigate the effect of intra-peritoneal injection of purified exudates of axenic Spirulina platensis on the mammalian endocrine and nervous systems. Methods: The intra-peritoneal injection of the cyanobacterial exudates in mice was applied. Sex hormonal levels of testosterone and progesterone were measured using radioimmunoassay while the follicular stimulating hormone and luteinizing hormone were evaluated by direct chemiluminescence. In addition, superoxide dismutase, ca...

  2. EXPERIENCE OF TREATMENT WITH FENSPIRIDE IN CHILDREN WITH CHRONIC EXUDATIVE OTITIS MEDIA AFTER TYMPANOSTOMY

    OpenAIRE

    L.A. Toropova; T.V. Zhuikova; N.I. Marysheva; A.I. Nikolaeva; Yu.S. Maiorova

    2009-01-01

    The trial presents the analysis of factors predisposing to exudative otitis media development in 709 children, needing regular audiologist’s check-up. It was shown that dominating risk factor of auditory tube’s function disorders is hypertrophy of palatine tonsil (it was detected in 69% of children). Besides, doctors from children’s out-patient clinics often use conservative treatment in children with chronic exudative otitis media. Analysis of data obtained at the time of treatment of 180 ho...

  3. Effect of gamma irradiation on rheological properties of polysaccharides exuded by A. fluccosus and A. gossypinus.

    Science.gov (United States)

    Alijani, Samira; Balaghi, Sima; Mohammadifar, Mohammad Amin

    2011-11-01

    In this study, Iranian gum tragacanth (GT) exudates from Astragalus fluccosus (AFG) and Astragalus gossypinus (AGG) were irradiated at 3, 7, 10 and 15 kGy. Fourier transform infrared spectroscopy (FTIR) data showed that irradiation did not induce changes in the chemical structure of either type of gum. Although particle size distribution and both steady shear and dynamic rheological properties were considerably affected by the irradiation process, the magnitude of the effect of irradiation on each of the rheological and size variables was different for the hydrocolloids. For instance, for AGG, increasing the irradiation dose from 3 to 10 kGy, the d(0.5) and D[3,2] values were reduced by one-sixth to one-eighth fold. Colour measurement revealed that the radiation process led to an increase in the yellow index and b* values for both types of GT in powder form, but it was more pronounced for AGG samples. Irradiation led to an approximate 13-fold increase in redness in AFG. Surface and shape changes of the gum crystals were studied by scanning electron microscope (SEM) and a smoother surface for irradiated samples was detected. The notable changes in functional properties of each variety of irradiated gum should be taken into consideration before using the radiation technology as a commercial tool for sterilisation. Copyright © 2011 Elsevier B.V. All rights reserved.

  4. Rheological Modeling and Characterization of Ficus platyphylla Gum Exudates

    Directory of Open Access Journals (Sweden)

    Nnabuk O. Eddy

    2013-01-01

    Full Text Available Ficus platyphylla gum exudates (FP gum have been analyzed for their physicochemical parameters and found to be ionic, mildly acidic, odourless, and yellowish brown in colour. The gum is soluble in water, sparingly soluble in ethanol, and insoluble in acetone and chloroform. The nitrogen (0.39% and protein (2.44% contents of the gum are relatively low. The concentrations of the cations were found to increase according to the following trend, Mn>Fe>Zn>Pb>Cu>Mg>Cd>Ca. Analysis of the FTIR spectrum of the gum revealed vibrations similar to those found in polysaccharides while the scanning electron micrograph indicated that the gum has irregular molecular shapes, arranged randomly. The intrinsic viscosity of FP gum estimated by extrapolating to zero concentrations in Huggins, Kraemer, Schulz-Blaschke, and Martin plots has an average value of 7 dL/g. From the plots of viscosity versus shear rate/speed of rotation and also that of shear stress versus shear rate, FP gum can be classified as a non-Newtonian gum with characteristics-plastic properties. Development of the Master_s curve for FP gum also indicated that the gum prefers to remain in a dilute domain (C

  5. A Low-Cost Imaging Method for the Temporal and Spatial Colorimetric Detection of Free Amines on Maize Root Surfaces

    Directory of Open Access Journals (Sweden)

    Truc H. Doan

    2017-08-01

    Full Text Available Plant root exudates are important mediators in the interactions that occur between plants and microorganisms in the soil, yet much remains to be learned about spatial and temporal variation in their production. This work outlines a method utilizing a novel colorimetric paper to detect spatial and temporal changes in the production of nitrogen-containing compounds on the root surface. While existing methods have made it possible to conduct detailed analysis of root exudate composition, relatively less is known about where in the root system exudates are produced and how this localization changes as the root grows. Furthermore, there is much to learn about how exudate localization and composition varies in response to stress. Root exudates are chemically diverse secretions composed of organic acids, amino acids, proteins, sugars, and other metabolites. The sensor utilized for the method, ninhydrin, is a colorless substance in solution that reacts with free amino groups to form a purple dye. A detection paper was developed by formulating ninhydrin into a print solution that was uniformly deposited onto paper with a commercial ink jet printer. This “ninhydrin paper” was used to analyze the chemical makeup of root surfaces from maize seedlings grown vertically on germination paper. Through contact between the ninhydrin paper and seedling root surfaces, combined with images of both the seedlings and dried ninhydrin papers captured using a standard flatbed scanner, nitrogen-containing substances on the root surface can be localized and concentration of signal estimated for over 2 weeks of development. The method was found to be non-inhibiting to plant growth over the analysis period although damage to root hairs was observed. The method is sensitive in the detection of free amines at concentrations as little as 140 μM. Furthermore, ninhydrin paper is stable, showing consistent color changes up to 2 weeks after printing. This relatively simple, low

  6. Root resorption

    DEFF Research Database (Denmark)

    Kjaer, Inger

    2014-01-01

    Introduction: This paper summarizes the different conditions, which have a well-known influence on the resorption of tooth roots, exemplified by trauma and orthodontic treatment. The concept of the paper is to summarize and explain symptoms and signs of importance for avoiding resorption during...... orthodontic treatment. The Hypothesis: The hypothesis in this paper is that three different tissue layers covering the root in the so-called periroot sheet can explain signs and symptoms of importance for avoiding root resorption during orthodontic treatment. These different tissue layers are; outermost...... processes provoked by trauma and orthodontic pressure. Inflammatory reactions are followed by resorptive processes in the periroot sheet and along the root surface. Evaluation of the Hypothesis: Different morphologies in the dentition are signs of abnormal epithelium or an abnormal mesodermal layer. It has...

  7. DESIGN AND DEVELOP A COMPUTER AIDED DESIGN FOR AUTOMATIC EXUDATES DETECTION FOR DIABETIC RETINOPATHY SCREENING

    Directory of Open Access Journals (Sweden)

    C. A. SATHIYAMOORTHY

    2016-04-01

    Full Text Available Diabetic Retinopathy is a severe and widely spread eye disease which can lead to blindness. One of the main symptoms for vision loss is Exudates and it could be prevented by applying an early screening process. In the Existing systems, a Fuzzy C-Means Clustering technique is used for detecting the exudates for analyzation. The main objective of this paper is, to improve the efficiency of the Exudates detection in diabetic retinopathy images. To do this, a three Stage – [TS] approach is introduced for detecting and extracting the exudates automatically from the retinal images for screening the Diabetic retinopathy. TS functions on the image in three levels such as Pre-processing the image, enhancing the image and detecting the Exudates accurately. After successful detection, the detected exudates are classified using GLCM method for finding the accuracy. The TS approach is experimented using MATLAB software and the performance evaluation can be proved by comparing the results with the existing approach’s result and with the hand-drawn ground truths images from the expert ophthalmologist.

  8. Carbon cost of the fungal symbiont relative to net leaf P accumulation in a split-root VA mycorrhizal symbiosis

    International Nuclear Information System (INIS)

    Douds, D.D. Jr.; Johnson, C.R.; Koch, K.E.

    1988-01-01

    Translocation of 14 C-photosynthates to mycorrhizal (++), half mycorrhizal (0+), and nonmycorrhizal (00) split-root systems was compared to P accumulation in leaves of the host plant. Carrizo citrange seedlings (Poncirus trifoliata [L.] Raf. x Citrus sinensis [L.] Osbeck) were inoculated with the vesicular-arbuscular mycorrhizal fungus Glomus intraradices Schenck and Smith. Plants were exposed to 14 CO 2 for 10 minutes and ambient air for 2 hours. Three to 4% of recently labeled photosynthate was allocated to metabolism of the mycorrhiza in each inoculated root half independent of shoot P concentration, growth response, and whether one or both root halves were colonized. Nonmycorrhizal roots respired more of the label translocated to them than did mycorrhizal roots. Label recovered in the potting medium due to exudation or transport into extraradical hyphae was 5 to 6 times greater for (++) versus (00) plants. In low nutrient media, roots of (0+) and (++) plants transported more P to leaves per root weight than roots of (00) plants. However, when C translocated to roots utilized for respiration, exudation, etc., as well as growth is considered, (00) plant roots were at least as efficient at P uptake (benefit) per C utilized (cost) as (0+) and (++) plants. Root systems of (++) plants did not supply more P to leaves than (0+) plants in higher nutrient media, yet they still allocated twice the 14 C-photosynthate to the mycorrhiza as did (0+) root systems

  9. Plants influence on arsenic availability and speciation in the rhizosphere, roots and shoots of three different vegetables

    International Nuclear Information System (INIS)

    Bergqvist, Claes; Herbert, Roger; Persson, Ingmar; Greger, Maria

    2014-01-01

    The toxicity of arsenic (As) in the environment is controlled by its concentration, availability and speciation. The aims of the study were to evaluate the accumulation and speciation of As in carrot, lettuce and spinach cultivated in soils with various As concentrations and to estimate the concomitant health risks associated with the consumption of the vegetables. Arsenic concentration and speciation in plant tissues and soils was analysed by HPLC, AAS and XANES spectroscopy. To estimate the plants influence in the rhizosphere, organic acids in lettuce root exudates were analysed by ion chromatography. The results showed that the As accumulation was higher in plants cultivated in soil with higher As extractability. Arsenate predominated in the soils, rhizosphere and root exudates of lettuce. Succinic acid was the major organic acid in lettuce root exudates. Ingestion of the tested vegetables may result in an intake of elevated levels of inorganic As. -- Highlights: • In soils with higher arsenic extractability, accumulation in plants was higher. • Arsenate predominated in the soils, rhizosphere and root exudates of lettuce. • Arsenite predominated in the shoots of healthy looking vegetables. -- Regardless of the initial level of extractable As in the soil, the plants almost doubled the extractable As in the rhizosphere soil

  10. Root growth and N dynamics in response to multi-year experimental warming, summer drought and elevated CO2 in a mixed heathland-grass ecosystem

    DEFF Research Database (Denmark)

    Arndal, M. F.; Schmidt, I. K.; Kongstad, J.

    2013-01-01

    growth would be matched by an increase in root nutrient uptake of NH4+-N and NO3- -N. Root growth was significantly increased by elevated CO2. The roots, however, did not fully compensate for the higher growth with a similar increase in nitrogen uptake per unit of root mass. Hence the nitrogen...... concentration in roots was decreased in elevated CO2, whereas the biomass N pool was unchanged or even increased. The higher net root production in elevated CO2 might be a strategy for the plants to cope with increased nutrient demand leading to a long-term increase in N uptake on a whole-plant basis. Drought...... reduced grass root biomass and N uptake, especially when combined with warming, but CO2 was the most pronounced main factor effect. Several significant interactions of the treatments were found, which indicates that the responses were nonadditive and that changes to multiple environmental changes cannot...

  11. Sugars en route to the roots. Transport, metabolism and storage within plant roots and towards microorganisms of the rhizosphere.

    Science.gov (United States)

    Hennion, Nils; Durand, Mickael; Vriet, Cécile; Doidy, Joan; Maurousset, Laurence; Lemoine, Rémi; Pourtau, Nathalie

    2018-04-28

    In plants, root is a typical sink organ that relies exclusively on the import of sugar from the aerial parts. Sucrose is delivered by the phloem to the most distant root tips and, en route to the tip, is used by the different root tissues for metabolism and storage. Besides, a certain portion of this carbon is exuded in the rhizosphere, supplied to beneficial microorganisms and diverted by parasitic microbes. The transport of sugars towards these numerous sinks either occurs symplastically through cell connections (plasmodesmata) or is apoplastically mediated through membrane transporters (MST, SUT/SUC and SWEET) that control monosaccharide and sucrose fluxes. Here, we review recent progresses on carbon partitioning within and outside roots, discussing membrane transporters involved in plant responses to biotic and abiotic factors. This article is protected by copyright. All rights reserved.

  12. Regulatory RNA at the root of animals: dynamic expression of developmental lincRNAs in the calcisponge Sycon ciliatum.

    Science.gov (United States)

    Bråte, Jon; Adamski, Marcin; Neumann, Ralf S; Shalchian-Tabrizi, Kamran; Adamska, Maja

    2015-12-22

    Long non-coding RNAs (lncRNAs) play important regulatory roles during animal development, and it has been hypothesized that an RNA-based gene regulation was important for the evolution of developmental complexity in animals. However, most studies of lncRNA gene regulation have been performed using model animal species, and very little is known about this type of gene regulation in non-bilaterians. We have therefore analysed RNA-Seq data derived from a comprehensive set of embryogenesis stages in the calcareous sponge Sycon ciliatum and identified hundreds of developmentally expressed intergenic lncRNAs (lincRNAs) in this species. In situ hybridization of selected lincRNAs revealed dynamic spatial and temporal expression during embryonic development. More than 600 lincRNAs constitute integral parts of differentially expressed gene modules, which also contain known developmental regulatory genes, e.g. transcription factors and signalling molecules. This study provides insights into the non-coding gene repertoire of one of the earliest evolved animal lineages, and suggests that RNA-based gene regulation was probably present in the last common ancestor of animals. © 2015 The Authors.

  13. A multi-step system for screening and localization of hard exudates in retinal images

    Science.gov (United States)

    Bopardikar, Ajit S.; Bhola, Vishal; Raghavendra, B. S.; Narayanan, Rangavittal

    2012-03-01

    The number of people being affected by Diabetes mellitus worldwide is increasing at an alarming rate. Monitoring of the diabetic condition and its effects on the human body are therefore of great importance. Of particular interest is diabetic retinopathy (DR) which is a result of prolonged, unchecked diabetes and affects the visual system. DR is a leading cause of blindness throughout the world. At any point of time 25 - 44% of people with diabetes are afflicted by DR. Automation of the screening and monitoring process for DR is therefore essential for efficient utilization of healthcare resources and optimizing treatment of the affected individuals. Such automation would use retinal images and detect the presence of specific artifacts such as hard exudates, hemorrhages and soft exudates (that may appear in the image) to gauge the severity of DR. In this paper, we focus on the detection of hard exudates. We propose a two step system that consists of a screening step that classifies retinal images as normal or abnormal based on the presence of hard exudates and a detection stage that localizes these artifacts in an abnormal retinal image. The proposed screening step automatically detects the presence of hard exudates with a high sensitivity and positive predictive value (PPV ). The detection/localization step uses a k-means based clustering approach to localize hard exudates in the retinal image. Suitable feature vectors are chosen based on their ability to isolate hard exudates while minimizing false detections. The algorithm was tested on a benchmark dataset (DIARETDB1) and was seen to provide a superior performance compared to existing methods. The two-step process described in this paper can be embedded in a tele-ophthalmology system to aid with speedy detection and diagnosis of the severity of DR.

  14. Hagfish slime exudate stabilization and its effect on slime formation and functionality.

    Science.gov (United States)

    Böni, L J; Zurflüh, R; Widmer, M; Fischer, P; Windhab, E J; Rühs, P A; Kuster, S

    2017-07-15

    Hagfish produce vast amounts of slime when under attack. The slime is the most dilute hydrogel known to date, and is a highly interesting material for biomaterial research. It forms from a glandular secrete, called exudate, which deploys upon contact with seawater. To study slime formation ex vivo and to characterize its material properties, stabilization of the sensitive slime exudate is crucial. In this study, we compared the two main stabilization methods, dispersion in high osmolarity citrate/PIPES (CP) buffer and immersion in oil, and tested the influence of time, temperature and pH on the stability of the exudate and functionality of the slime. Using water retention measurements to assess slime functionality, we found that CP buffer and oil preserved the exudate within the first 5 hours without loss of functionality. For longer storage times, slime functionality decreased for both stabilization methods, for which the breakdown mechanisms differed. Stabilization in oil likely favored temperature-sensitive osmotic-driven swelling and rupture of the mucin vesicles, causing the exudate to gel and clump. Extended storage in CP buffer resulted in an inhibited unraveling of skeins. We suggest that a water soluble protein glue, which mediates skein unraveling in functional skeins, denatures and gradually becomes insoluble during storage in CP buffer. The breakdown was accentuated when the pH of the CP buffer was raised from pH 6.7 to pH 8.5, probably caused by increased denaturation of the protein glue or by inferior vesicle stabilization. However, when fresh exudate was mixed into seawater or phosphate buffer at pH 6-9, slime functionality was not affected, showing pH insensitivity of the slime formation around a neutral pH. These insights on hagfish exudate stabilization mechanisms will support hagfish slime research at a fundamental level, and contribute to resolve the complex mechanisms of skein unraveling and slime formation. © 2017. Published by The Company

  15. Root-induced changes of Zn and Pb dynamics in the rhizosphere of sunflower with different plant growth promoting treatments in a heavily contaminated soil.

    Science.gov (United States)

    Mousavi, Seyed Majid; Motesharezadeh, Babak; Hosseini, Hossein Mirseyed; Alikhani, Hoseinali; Zolfaghari, Ali Asghar

    2018-01-01

    Root induced changes are deemed to have an important role in the success of remediation techniques in contaminated soils. Here, the effects of two nano-particles [SiO 2 and zeolite] with an application rate of 200mgkg -1 , and two bacteria [Bacillus safensis FO-036b(T) and Pseudomonas fluorescens p.f.169] in the rhizosphere of sunflower on Zn and Pb dynamics were studied in greenhouse conditions. The treatments reduced the exchangeable Zn (from 13.68% to 30.82%) and Pb (from 10.34% to 25.92%) in the rhizosphere compared to the control. The EC and microbial respiration/population of the rhizosphere and bulk soil had an opposite trend with the exchangeable fraction of Zn and Pb, but dissolved organic carbon followed a similar trend with the more bioavailable fractions. As a result, the accumulation of Pb and Zn in the plant tissues was significantly (p soil, depending on the chemical character of the metals and the treatments. Generally, the affinity of the biotic treatment for Pb was more than the abiotic and conversely, the abiotic treatment showed a higher ability to immobilize Zn than the biotic treatment. Copyright © 2017 Elsevier Inc. All rights reserved.

  16. Root (Botany)

    Science.gov (United States)

    Robert R. Ziemer

    1981-01-01

    Plant roots can contribute significantly to the stability of steep slopes. They can anchor through the soil mass into fractures in bedrock, can cross zones of weakness to more stable soil, and can provide interlocking long fibrous binders within a weak soil mass. In deep soil, anchoring to bedrock becomes negligible, and lateral reinforcement predominates

  17. Analytical studies on the gum exudate from Anogeissus leiocarpus

    International Nuclear Information System (INIS)

    Ahmed, Samia Eltayeb

    1999-04-01

    Anogeissus leiocarpus gum samples were collected as natural exudate nodules, from three different location. Physicochemical properties of gum samples were studied. results showed significant differences within each location in most parameters studied except refractive index value which was found to be constant in all samples. The effect of location on the properties of gum samples was also studied and the analysis of variance showed insignificant differences (P≤0.05) in all properties studied except in ash content. Inter nodule variations of gum from two different location were studied individually. Results showed significant differences for each parameter studied except for the refractive index value. The properties studied of all gum samples were as follows: 9.2% moisture, 3.4% ash, 0.72% nitrogen, 4.74% protein, -35.5 specific rotation, 1.68 relative viscosity, 4.2 pH, 1.334 refractive index, 14.3 uronic acid, 0.44% reducing sugar, 1336.0 equivalent weight and 0.68% tannin content. UV absorption spectra of gum samples and gum nodules were determined. Cationic composition of gum samples was also determined and the results showed that (Mg) has highest value in all samples studied followed by Fe, Na, K, Ca, Zn and trace amount of Mn, Co, Ni, Cd and Pb. The water holding capacity was found to be 65.5% and emulsifying stability was found to be 1.008. The component sugars of gum were examined by different methods followed by qualitative and quantitative analysis. Analysis of hydrolysate crude gum sample by HPLC show L-rhamnose (6.82), L-arabinose (48.08), D-galactose (11.26) and two unknown oligosaccharides having values (0.22 and 32.61). Some physicochemical properties were studied. Results showed significant differences in nitrogen and protein contents, specific rotation, relative viscosity, equivalent weight and pH of fractions, where as insignificant differences were observed in uronic acid content and refractive index values

  18. ELEVATED CO2 AND ELEVATED TEMPERATURE HAVE NO EFFECT ON DOUGLAS-FIR FINE-ROOT DYNAMICS IN NITROGEN-POOR SOIL

    Science.gov (United States)

    Here, we investigate fine-root production, mortality and standing crop of Douglas-fir (Pseudotsuga menziesii) seedlings exposed to elevated atmospheric CO2 and elevated air temperature. We hypothesized that these treatments would increase fine-root production, but that mortality ...

  19. Solid phase extraction and metabolic profiling of exudates from living copepods

    DEFF Research Database (Denmark)

    Selander, Erik; Heuschele, Jan; Nylund, Göran M.

    2016-01-01

    describe the development of a closed loop solid phase extraction setup that allows for extraction of exuded metabolites from live copepods. We captured exudates from male and female Temora longicornis and analyzed the content with high resolution LC-MS. Chemometric methods revealed 87 compounds...... that solid phase extraction in combination with metabolic profiling of exudates is a useful tool to develop our understanding of the chemical interplay between pelagic organisms....... Copepodamide G, known to induce defensive responses in phytoplankton, was among the ten compounds of highest relative abundance in both male and female extracts. The presence of copepodamide G shows that the method can be used to capture and analyze chemical signals from living source organisms. We conclude...

  20. Biodegradation of polycyclic aromatic hydrocarbons, selection and dynamics of bacterial populations in the rhizosphere in relation with the distance to roots; Biodegradation des Hydrocarbures Aromatiques Polycycliques, selection et dynamique des populations bacteriennes dans la rhizosphere en fonction de la distance aux racines

    Energy Technology Data Exchange (ETDEWEB)

    Corgie, St.

    2004-03-01

    The biodegradation of Polycyclic Aromatic Hydrocarbons (PAH) is mainly performed by microorganisms that can use these compounds as sole source of carbon and energy. Such capacity has been amply studied to use and optimise microbial activity for remediation of contaminated soils. The use of plants has been suggested to increase and accelerate biodegradation rate by improving microbial activity. However, biodegradation mechanisms still remain poorly described as the interactions between plant, pollutant and rhizosphere microflora are often complex. A simplified compartmented device was developed to study rhizospheric processes, especially biodegradation of PAH, as a function of distance to roots, where root exudates and/or PAH were the only carbon sources for microbial growth. The development and use of bio-molecular techniques (nucleic acid isolation, PCR, RT-PCR, TGGE, hybridization with a degradation gene specific probe) permitted to follow the structure of bacterial communities. Gradients of phenanthrene biodegradation were observed as a function of distance to roots, in parallel to spatial and temporal variations in bacterial community structure. These bacterial communities, as well as PAH biodegradation rate, also depended on the aromaticity of PAH and were modified by the symbiosis between plant and an arbuscular mycorrhizal fungus. (author)

  1. Effect of intravitreal bevacizumab on diabetic macular edema with hard exudates

    Science.gov (United States)

    Jeon, Sohee; Lee, Won Ki

    2014-01-01

    Background We evaluated the efficacy of intravitreal bevacizumab on diabetic macular edema with subfoveal and perifoveal hard exudates. Materials and methods Eleven eyes (11 patients) exhibiting diabetic macular edema with subfoveal and perifoveal hard exudates were included in this prospective, nonrandomized interventional pilot study. All patients were treated with monthly scheduled intravitreal bevacizumab injections for 6 months. Changes in the Early Treatment Diabetic Retinopathy Study best corrected visual acuity, amount of hard exudates on fundus photography, and macular edema detected by central subfield thickness on spectral domain optical coherence tomography after six serial injections, were assessed. The amount of hard exudates at each visit was evaluated as pixels in fundus photography, using an Adobe Photoshop program. Results Ten of 11 patients completed follow-up. The mean Early Treatment Diabetic Retinopathy Study best corrected visual acuity was 59.9±5.7 letters (Snellen equivalent, 20/63) at baseline evaluation. The best corrected visual acuity exhibited no significant difference at month 6 compared with at baseline (57.9±6.0 letters or 20/70 at month 6; P=0.085). At month 6, mean central subfield thickness decreased from 370.4±56.5 to 334.6±65.0 μm (P=0.009). The mean amount of hard exudates increased from 4467.1±2736.1 to 6592.4±2498.3 pixels at month 6 (P=0.022). No serious adverse events occurred. Conclusion Continuous intravitreal bevacizumab was found to have no benefit in visual acuity and amount of hard exudates, despite the improvement of macular edema at 6 months. PMID:25143708

  2. Mevalonate-derived quinonemethide triterpenoid from in vitro roots of Peritassa laevigata and their localization in root tissue by MALDI imaging

    Science.gov (United States)

    Pina, Edieidia S.; Silva, Denise B.; Teixeira, Simone P.; Coppede, Juliana S.; Furlan, Maysa; França, Suzelei C.; Lopes, Norberto P.; Pereira, Ana Maria S.; Lopes, Adriana A.

    2016-03-01

    Biosynthetic investigation of quinonemethide triterpenoid 22β-hydroxy-maytenin (2) from in vitro root cultures of Peritassa laevigata (Celastraceae) was conducted using 13C-precursor. The mevalonate pathway in P. laevigata is responsible for the synthesis of the quinonemethide triterpenoid scaffold. Moreover, anatomical analysis of P. laevigata roots cultured in vitro and in situ showed the presence of 22β-hydroxy-maytenin (2) and maytenin (1) in the tissues from transverse or longitudinal sections with an intense orange color. MALDI-MS imaging confirmed the distribution of (2) and (1) in the more distal portions of the root cap, the outer cell layers, and near the vascular cylinder of P. laevigata in vitro roots suggesting a role in plant defense against infection by microorganisms as well as in the root exudation processes.

  3. Nanobiotechnology approach using plant rooting hormone synthesized silver nanoparticle as “nanobullets” for the dynamic applications in horticulture – An in vitro and ex vitro study

    Directory of Open Access Journals (Sweden)

    Raja Muthuramalingam Thangavelu

    2018-01-01

    Full Text Available Horticulture is the branch of agriculture that deals with science and technology and business of plant cultivation and it is considered to be the foremost part of the world economy. Even though, one of the major challenges which has seriously influenced the economic loss of horticulture is rooting of cuttings and root growth inhibiting plant pathogens. To address this issue through nanobiotechnology, we ingeniously build a concept of silver nanoparticles (AgNPs as “nano-bullets” can act for a dual mode like root enhancer and pathogen destroyer on the target site. After that, we succeeded in AgNPs synthesis, using two auxin rooting hormones of Indole-3-acetic acid and Indole-3-butyric acid as a reducing cum stabilizing agent. Further, its efficacy of root promoting and pathogen inhibitory action was sufficiently validated through in vitro and ex vitro studies with model plants and plant pathogens. As a result, the action duality of hormone-stabilized AgNPs was manifested to threefold enhanced root growth compared to controls and it increased the rooting capabilities against root growth inhibiting phytopathogens. This feature was also proved by the direct antifungal assay. Moreover, hormone-AgNPs left no toxicity to treated plants which was revealed by RAPD molecular markers. Therefore, with a detailed study and analysis with instruments such as Spectroscopy, TEM, Zetasizer, FTIR, Cyclic Voltammetry, Fluorescence microscopy (nanoparticles uptake, SEM coupled with EDS (bioaccumulation, TGA (grafting density and PCR (RAPD analysis, this study can unravel the relevance, scope and current challenges at horticulture plants root development and plant disease management for the sustainable agricultural crop production.

  4. Tunnel technique with connective tissue graft versus coronally advanced flap with enamel matrix derivative for root coverage: a RCT using 3D digital measuring methods. Part II. Volumetric studies on healing dynamics and gingival dimensions.

    Science.gov (United States)

    Rebele, Stephan F; Zuhr, Otto; Schneider, David; Jung, Ronny E; Hürzeler, Markus B

    2014-06-01

    The aim of this randomized clinical trial (RCT) was to compare the clinical performance of the tunnel technique with subepithelial connective tissue graft (TUN) versus a coronally advanced flap with enamel matrix derivative (CAF) in the treatment of gingival recession defects. The use of innovative 3D digital measuring methods allowed to study healing dynamics at connective tissue (CT)-grafted sites and to evaluate the influence of the thickness of the root covering soft tissues on the outcome of surgical root coverage. Twenty-four patients contributed a total of 47 Miller class I or II recessions for scientific evaluation. Precise study models collected at baseline and follow-up examinations were optically scanned and virtually superimposed for digital evaluation of clinical outcome measures including mean marginal soft tissue thickness (THK). Healing dynamics were measured in a defined region of interest at CT-grafted sites where volume differences between time points were calculated. At 12 months, recession reduction as well as mean root coverage were significantly better at CT-grafted sites treated in the TUN group (1.94 mm and 98.4% respectively) compared to the non-augmented sites of the CAF group (1.17 mm and 71.8% respectively) and statistical analysis revealed a positive correlation of THK (1.63 mm TUN versus 0.91 mm CAF, p tissue healing following surgical root coverage with CT-grafting was mainly accomplished after 6 months, with around two-thirds of the augmented volume being maintained after 12 months. The TUN resulted in thicker gingiva and better clinical outcomes compared to CAF. Increased gingival thickness was associated with better surgical outcomes in terms of recession reduction and root coverage. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  5. Dynamics of soil exploration by fine roots down to a depth of 10 m throughout the entire rotation in Eucalyptus grandis plantations

    Directory of Open Access Journals (Sweden)

    Jean-Paul eLaclau

    2013-07-01

    Full Text Available Although highly weathered soils cover considerable areas in tropical regions, little is known about exploration by roots in deep soil layers. Intensively managed Eucalyptus plantations are simple forest ecosystems that can provide an insight into the belowground growth strategy of fast-growing tropical trees. Fast exploration of deep soil layers by eucalypt fine roots may contribute to achieving a gross primary production (GPP that is among the highest in the world for forests. Soil exploration by fine roots down to a depth of 10 m was studied throughout the complete cycle of Eucalyptus plantations. Intersects of fine roots, less than 1 mm in diameter, and medium-sized roots, 1-3 mm in diameter, were counted on trench walls in a chronosequence of 1-, 2-, 3.5- and 6-year-old plantations on a sandy soil, as well as in an adjacent 6-year-old stand growing in a clayey soil. Two soil profiles were studied down to a depth of 10 m in each stand (down to 6 m at ages 1 and 2 years. The root intersects were counted on 224 m2 of trench walls in 15 pits. Monitoring the soil water content showed that, after clear-cutting, almost all the available water stored down to a depth of 7 m was taken up by tree roots within 1.1 year of planting. The soil space was explored intensively by fine roots down to a depth of 3 m from 1 year after planting, with an increase in anisotropy in the upper layers throughout the stand cycle. About 60% of fine root intersects were found at a depth of more than 1 m, irrespective of stand age. The root distribution was isotropic in deep soil layers and kriged maps showed fine root clumping. The results showed that a considerable volume of soil was explored by fine roots in eucalypt plantations on deep tropical soils, which might prevent water and nutrient losses by deep drainage after canopy closure and contribute to maximizing resource uses.

  6. Locally Finite Root Supersystems

    OpenAIRE

    Yousofzadeh, Malihe

    2013-01-01

    We introduce the notion of locally finite root supersystems as a generalization of both locally finite root systems and generalized root systems. We classify irreducible locally finite root supersystems.

  7. Antimicrobial susceptibility of Staphylococcus hyicus Isolated from exudative epidermitis in pigs

    DEFF Research Database (Denmark)

    Wegener, Henrik Caspar; Watts, J.L.; Salmon, S.A.

    1994-01-01

    for their activities against 100 S. hyicus strains isolated from pigs with exudative epidermitis. Novobiocin was the most active compound tested, with an MIC for 90% of the strains tested (MIC(90)) of less than or equal to 0.06 mu g/ml. Enrofloxacin, ampicillin, and ceftiofur were the next most active compounds...

  8. Use of hydrocapillary dressing in the management of highly exuding ulcers

    DEFF Research Database (Denmark)

    Norkus, A.; Dargis, V.; Thomsen, J.K.

    2005-01-01

    was conducted on 97 patients with an ankle brachial pressure index > or = 0.8 and a highly exuding leg ulcer. Ulcer duration was at least four weeks.Treatment continued until healing or for a maximum of 12 months. RESULTS: There was no statistically significant difference in healing time or wound area reduction...

  9. Antioxidant capacity of flavonoids and a new arylphenol of the resinous exudate from Heliotropium sinuatum.

    Science.gov (United States)

    Modak, Brenda; Torres, René; Lissi, Eduardo; delle Monache, Franco

    2003-12-01

    From the resinous exudate of Heliotropium sinuatum (family Boraginaceae), a new compound: 4-(3',5'-dihydroxynonadecyl)phenol 1, together with eight previously described flavonoids, were isolated and their antioxidant activities were assessed by quenching measurements with ABTS and DPPH cation radicals.

  10. Organic anion exudation by ectomycorrhizal fungi and Pinus sylvestris in response to nutrient deficiences

    NARCIS (Netherlands)

    Schöll, van L.; Hoffland, E.; Breemen, van N.

    2006-01-01

    Low molecular weight organic anions (LMWOA) can enhance weathering of mineral grains. We tested the hypothesis that ectomycorrhizal (EcM) fungi and tree seedlings increase their exudation of LMWOA when supply of magnesium, potassium and phosphorus is low to enhance the mobilization of Mg, K and P

  11. Machine learning approach to automatic exudate detection in retinal images from diabetic patients

    Science.gov (United States)

    Sopharak, Akara; Dailey, Matthew N.; Uyyanonvara, Bunyarit; Barman, Sarah; Williamson, Tom; Thet Nwe, Khine; Aye Moe, Yin

    2010-01-01

    Exudates are among the preliminary signs of diabetic retinopathy, a major cause of vision loss in diabetic patients. Early detection of exudates could improve patients' chances to avoid blindness. In this paper, we present a series of experiments on feature selection and exudates classification using naive Bayes and support vector machine (SVM) classifiers. We first fit the naive Bayes model to a training set consisting of 15 features extracted from each of 115,867 positive examples of exudate pixels and an equal number of negative examples. We then perform feature selection on the naive Bayes model, repeatedly removing features from the classifier, one by one, until classification performance stops improving. To find the best SVM, we begin with the best feature set from the naive Bayes classifier, and repeatedly add the previously-removed features to the classifier. For each combination of features, we perform a grid search to determine the best combination of hyperparameters ν (tolerance for training errors) and γ (radial basis function width). We compare the best naive Bayes and SVM classifiers to a baseline nearest neighbour (NN) classifier using the best feature sets from both classifiers. We find that the naive Bayes and SVM classifiers perform better than the NN classifier. The overall best sensitivity, specificity, precision, and accuracy are 92.28%, 98.52%, 53.05%, and 98.41%, respectively.

  12. The role of haemorrhage and exudate detection in automated grading of diabetic retinopathy.

    Science.gov (United States)

    Fleming, Alan D; Goatman, Keith A; Philip, Sam; Williams, Graeme J; Prescott, Gordon J; Scotland, Graham S; McNamee, Paul; Leese, Graham P; Wykes, William N; Sharp, Peter F; Olson, John A

    2010-06-01

    Automated grading has the potential to improve the efficiency of diabetic retinopathy screening services. While disease/no disease grading can be performed using only microaneurysm detection and image-quality assessment, automated recognition of other types of lesions may be advantageous. This study investigated whether inclusion of automated recognition of exudates and haemorrhages improves the detection of observable/referable diabetic retinopathy. Images from 1253 patients with observable/referable retinopathy and 6333 patients with non-referable retinopathy were obtained from three grading centres. All images were reference-graded, and automated disease/no disease assessments were made based on microaneurysm detection and combined microaneurysm, exudate and haemorrhage detection. Introduction of algorithms for exudates and haemorrhages resulted in a statistically significant increase in the sensitivity for detection of observable/referable retinopathy from 94.9% (95% CI 93.5 to 96.0) to 96.6% (95.4 to 97.4) without affecting manual grading workload. Automated detection of exudates and haemorrhages improved the detection of observable/referable retinopathy.

  13. Exudate detection in color retinal images for mass screening of diabetic retinopathy.

    Science.gov (United States)

    Zhang, Xiwei; Thibault, Guillaume; Decencière, Etienne; Marcotegui, Beatriz; Laÿ, Bruno; Danno, Ronan; Cazuguel, Guy; Quellec, Gwénolé; Lamard, Mathieu; Massin, Pascale; Chabouis, Agnès; Victor, Zeynep; Erginay, Ali

    2014-10-01

    The automatic detection of exudates in color eye fundus images is an important task in applications such as diabetic retinopathy screening. The presented work has been undertaken in the framework of the TeleOphta project, whose main objective is to automatically detect normal exams in a tele-ophthalmology network, thus reducing the burden on the readers. A new clinical database, e-ophtha EX, containing precisely manually contoured exudates, is introduced. As opposed to previously available databases, e-ophtha EX is very heterogeneous. It contains images gathered within the OPHDIAT telemedicine network for diabetic retinopathy screening. Image definition, quality, as well as patients condition or the retinograph used for the acquisition, for example, are subject to important changes between different examinations. The proposed exudate detection method has been designed for this complex situation. We propose new preprocessing methods, which perform not only normalization and denoising tasks, but also detect reflections and artifacts in the image. A new candidates segmentation method, based on mathematical morphology, is proposed. These candidates are characterized using classical features, but also novel contextual features. Finally, a random forest algorithm is used to detect the exudates among the candidates. The method has been validated on the e-ophtha EX database, obtaining an AUC of 0.95. It has been also validated on other databases, obtaining an AUC between 0.93 and 0.95, outperforming state-of-the-art methods. Copyright © 2014 Elsevier B.V. All rights reserved.

  14. Decision support system for the detection and grading of hard exudates from color fundus photographs

    Science.gov (United States)

    Jaafar, Hussain F.; Nandi, Asoke K.; Al-Nuaimy, Waleed

    2011-11-01

    Diabetic retinopathy is a major cause of blindness, and its earliest signs include damage to the blood vessels and the formation of lesions in the retina. Automated detection and grading of hard exudates from the color fundus image is a critical step in the automated screening system for diabetic retinopathy. We propose novel methods for the detection and grading of hard exudates and the main retinal structures. For exudate detection, a novel approach based on coarse-to-fine strategy and a new image-splitting method are proposed with overall sensitivity of 93.2% and positive predictive value of 83.7% at the pixel level. The average sensitivity of the blood vessel detection is 85%, and the success rate of fovea localization is 100%. For exudate grading, a polar fovea coordinate system is adopted in accordance with medical criteria. Because of its competitive performance and ability to deal efficiently with images of variable quality, the proposed technique offers promising and efficient performance as part of an automated screening system for diabetic retinopathy.

  15. Influence of aluminum on growth, mineral nutrition and organic acid exudation of rambutan (Nephelium lappaceum)

    Science.gov (United States)

    A randomized complete block design experiment with six aluminum (Al) concentrations was carried out to evaluate the effect of aluminum on nutrient content, plant growth, dry matter production and Al-induced organic acid exudation in rambutan (Nephelium lappaceum). One rambutan cultivar was grown in...

  16. THE HYDROGEN ION CONCENTRATION OF JOINT EXUDATES IN RHEUMATIC FEVER AND OTHER FORMS OF ARTHRITIS.

    Science.gov (United States)

    Boots, R H; Cullen, G E

    1922-09-30

    1. The hydrogen ion concentration of joint exudates aspirated from patients ill with acute rheumatic fever, arthritis of undetermined origin, and bacterial arthritis was determined. The hydrogen ion concentrations of the joint exudates from patients with acute rheumatic fever approximated the normal reaction of blood, varying from pH 7.27 to 7.42. Exudates from patients with arthritis of undetermined origin varied in pH from 7.33 to 7.47. The pH of a joint effusion occurring in a patient with myocardial insufficiency was 7.34. Bacteriologically, all of these fluids were sterile by ordinary means of cultivation. An exudate aspirated from a knee infected with Staphylococcus aureus had a pH of 6.69, while that from a patient having an arthritis due to Streptococcus hoemolyticus was also acid, having a pH of 6.19. 2. Since a definitely acid medium is necessary for the liberation of free salicylic acid and since all of the joint fluids from patients with acute rheumatic fever were slightly alkaline, no free salicylic acid could possibly exist in such joint fluids following the administration of salicylates.

  17. Effects of fine root length density and root biomass on soil preferential flow in forest ecosystems

    Directory of Open Access Journals (Sweden)

    Yinghu Zhang

    2015-04-01

    Full Text Available Aim of study: The study was conducted to characterize the impacts of plant roots systems (e.g., root length density and root biomass on soil preferential flow in forest ecosystems. Area of study: The study was carried out in Jiufeng National Forest Park, Beijing, China. Material and methods: The flow patterns were measured by field dye tracing experiments. Different species (Sophora japonica Linn,Platycladus orientalis Franco, Quercus dentata Thunbwere quantified in two replicates, and 12 soil depth were applied. Plant roots were sampled in the sieving methods. Root length density and root biomass were measured by WinRHIZO. Dye coverage was implied in the image analysis, and maximum depth of dye infiltration by direct measurement. Main results: Root length density and root biomass decreased with the increasing distance from soil surface, and root length density was 81.6% higher in preferential pathways than in soil matrix, and 66.7% for root biomass with respect to all experimental plots. Plant roots were densely distributed in the upper soil layers. Dye coverage was almost 100% in the upper 5-10 cm, but then decreased rapidly with soil depth. Root length density and root biomass were different from species: Platycladus orientalis Franco > Quercus dentata Thunb > Sophora japonica Linn. Research highlights: The results indicated that fine roots systems had strong effects on soil preferential flow, particularly root channels enhancing nutrition transport across soil profiles in forest dynamics.

  18. Can we manipulate root system architecture to control soil erosion?

    Science.gov (United States)

    Ola, A.; Dodd, I. C.; Quinton, J. N.

    2015-09-01

    Soil erosion is a major threat to soil functioning. The use of vegetation to control erosion has long been a topic for research. Much of this research has focused on the above-ground properties of plants, demonstrating the important role that canopy structure and cover plays in the reduction of water erosion processes. Less attention has been paid to plant roots. Plant roots are a crucial yet under-researched factor for reducing water erosion through their ability to alter soil properties, such as aggregate stability, hydraulic function and shear strength. However, there have been few attempts to specifically manipulate plant root system properties to reduce soil erosion. Therefore, this review aims to explore the effects that plant roots have on soil erosion and hydrological processes, and how plant root architecture might be manipulated to enhance its erosion control properties. We demonstrate the importance of root system architecture for the control of soil erosion. We also show that some plant species respond to nutrient-enriched patches by increasing lateral root proliferation. The erosional response to root proliferation will depend upon its location: at the soil surface dense mats of roots may reduce soil erodibility but block soil pores thereby limiting infiltration, enhancing runoff. Additionally, in nutrient-deprived regions, root hair development may be stimulated and larger amounts of root exudates released, thereby improving aggregate stability and decreasing erodibility. Utilizing nutrient placement at specific depths may represent a potentially new, easily implemented, management strategy on nutrient-poor agricultural land or constructed slopes to control erosion, and further research in this area is needed.

  19. Clinical significance of dental root canal microflora.

    Science.gov (United States)

    Gomes, B P; Lilley, J D; Drucker, D B

    1996-01-01

    Previous work by this group has shown that a significant association exists between pain and the presence of either Prevotella or Peptostreptococcus spp. in dental root canals. The aim of this study was to examine a more extensive series of canals microbiologically, to determine whether any other particular endodontic symptoms or clinical signs showed specific associations with individual bacterial species. Seventy root canals were examined microbiologically and clinical data collected to investigate in detail such associations. Of the canals studied, 37 were associated with pain, 49 with tenderness to percussion, 23 with swelling, six with purulent exudate and 57 presented with wet root canals. Anaerobes were isolated from 70.3% of painful canals and from 29.7% of pain-free canals. Significant associations were found between (a) pain and either Prevotella spp. or peptostreptococci, both with P spp. (P Eubacterium spp. (P spp. or Pstr. micros, both with P spp. (each P Eubacterium, Peptostreptococcus, Prevotella or Propionibacterium (each P < 0.05). It was concluded that several different endodontic clinical signs and symptoms are significantly associated with specific bacterial species.

  20. Macromolecular composition of phloem exudate from white lupin (Lupinus albus L.

    Directory of Open Access Journals (Sweden)

    Mann Anthea J

    2011-02-01

    Full Text Available Abstract Background Members of the legume genus Lupinus exude phloem 'spontaneously' from incisions made to the vasculature. This feature was exploited to document macromolecules present in exudate of white lupin (Lupinus albus [L.] cv Kiev mutant, in particular to identify proteins and RNA molecules, including microRNA (miRNA. Results Proteomic analysis tentatively identified 86 proteins from 130 spots collected from 2D gels analysed by partial amino acid sequence determination using MS/MS. Analysis of a cDNA library constructed from exudate identified 609 unique transcripts. Both proteins and transcripts were classified into functional groups. The largest group of proteins comprised those involved in metabolism (24%, followed by protein modification/turnover (9%, redox regulation (8%, cell structural components (6%, stress and defence response (6% with fewer in other groups. More prominent proteins were cyclophilin, ubiquitin, a glycine-rich RNA-binding protein, a group of proteins that comprise a glutathione/ascorbate-based mechanism to scavenge oxygen radicals, enzymes of glycolysis and other metabolism including methionine and ethylene synthesis. Potential signalling macromolecules such as transcripts encoding proteins mediating calcium level and the Flowering locus T (FT protein were also identified. From around 330 small RNA clones (18-25 nt 12 were identified as probable miRNAs by homology with those from other species. miRNA composition of exudate varied with site of collection (e.g. upward versus downward translocation streams and nutrition (e.g. phosphorus level. Conclusions This is the first inventory of macromolecule composition of phloem exudate from a species in the Fabaceae, providing a basis to identify systemic signalling macromolecules with potential roles in regulating development, growth and stress response of legumes.

  1. Immunotherapy for choroidal neovascularization in a laser-induced mouse model simulating exudative (wet) macular degeneration

    Science.gov (United States)

    Bora, Puran S.; Hu, Zhiwei; Tezel, Tongalp H.; Sohn, Jeong-Hyeon; Kang, Shin Goo; Cruz, Jose M. C.; Bora, Nalini S.; Garen, Alan; Kaplan, Henry J.

    2003-03-01

    Age-related macular degeneration (AMD) is the leading cause of blindness after age 55 in the industrialized world. Severe loss of central vision frequently occurs with the exudative (wet) form of AMD, as a result of the formation of a pathological choroidal neovasculature (CNV) that damages the macular region of the retina. We tested the effect of an immunotherapy procedure, which had been shown to destroy the pathological neovasculature in solid tumors, on the formation of laser-induced CNV in a mouse model simulating exudative AMD in humans. The procedure involves administering an Icon molecule that binds with high affinity and specificity to tissue factor (TF), resulting in the activation of a potent cytolytic immune response against cells expressing TF. The Icon binds selectively to TF on the vascular endothelium of a CNV in the mouse and pig models and also on the CNV of patients with exudative AMD. Here we show that the Icon dramatically reduces the frequency of CNV formation in the mouse model. After laser treatment to induce CNV formation, the mice were injected either with an adenoviral vector encoding the Icon, resulting in synthesis of the Icon by vector-infected mouse cells, or with the Icon protein. The route of injection was i.v. or intraocular. The efficacy of the Icon in preventing formation of laser-induced CNV depends on binding selectively to the CNV. Because the Icon binds selectively to the CNV in exudative AMD as well as to laser-induced CNV, the Icon might also be efficacious for treating patients with exudative AMD.

  2. Tryptophan exposure and accessibility in the chitooligosaccharide-specific phloem exudate lectin from pumpkin (Cucurbita maxima). A fluorescence study.

    Science.gov (United States)

    Narahari, Akkaladevi; Swamy, Musti J

    2009-10-06

    The exposure and accessibility of the tryptophan residues in the chitooligosaccharide-specific pumpkin (Cucurbita maxima) phloem exudate lectin (PPL) have been investigated by fluorescence spectroscopy. The emission lambda(max) of native PPL, seen at 338nm was red-shifted to 348nm upon denaturation by 6M Gdn.HCl in the presence of 10mM beta-mercaptoethanol, indicating near complete exposure of the tryptophan residues to the aqueous medium, whereas a blue-shift to 335nm was observed in the presence of saturating concentrations of chitotriose, suggesting that ligand binding leads to a decrease in the solvent exposure of the tryptophan residues. The extent of quenching was maximum with the neutral molecule, acrylamide whereas the ionic species, iodide and Cs(+) led to significantly lower quenching, which could be attributed to the presence of charged amino acid residues in close proximity to some of the tryptophan residues. The Stern-Volmer plot for acrylamide was linear for native PPL and upon ligand binding, but became upward curving upon denaturation, indicating that the quenching occurs via a combination of static and dynamic mechanisms. In time-resolved fluorescence experiments, the decay curves could be best fit to biexponential patterns, for native protein, in the presence of ligand and upon denaturation. In each case both lifetimes systematically decreased with increasing acrylamide concentrations, indicating that quenching occurs predominantly via a dynamic process.

  3. Bacillus subtilis Early Colonization of Arabidopsis thaliana Roots Involves Multiple Chemotaxis Receptors.

    Science.gov (United States)

    Allard-Massicotte, Rosalie; Tessier, Laurence; Lécuyer, Frédéric; Lakshmanan, Venkatachalam; Lucier, Jean-François; Garneau, Daniel; Caudwell, Larissa; Vlamakis, Hera; Bais, Harsh P; Beauregard, Pascale B

    2016-11-29

    Colonization of plant roots by Bacillus subtilis is mutually beneficial to plants and bacteria. Plants can secrete up to 30% of their fixed carbon via root exudates, thereby feeding the bacteria, and in return the associated B. subtilis bacteria provide the plant with many growth-promoting traits. Formation of a biofilm on the root by matrix-producing B. subtilis is a well-established requirement for long-term colonization. However, we observed that cells start forming a biofilm only several hours after motile cells first settle on the plant. We also found that intact chemotaxis machinery is required for early root colonization by B. subtilis and for plant protection. Arabidopsis thaliana root exudates attract B. subtilis in vitro, an activity mediated by the two characterized chemoreceptors, McpB and McpC, as well as by the orphan receptor TlpC. Nonetheless, bacteria lacking these chemoreceptors are still able to colonize the root, suggesting that other chemoreceptors might also play a role in this process. These observations suggest that A. thaliana actively recruits B. subtilis through root-secreted molecules, and our results stress the important roles of B. subtilis chemoreceptors for efficient colonization of plants in natural environments. These results demonstrate a remarkable strategy adapted by beneficial rhizobacteria to utilize carbon-rich root exudates, which may facilitate rhizobacterial colonization and a mutualistic association with the host. Bacillus subtilis is a plant growth-promoting rhizobacterium that establishes robust interactions with roots. Many studies have now demonstrated that biofilm formation is required for long-term colonization. However, we observed that motile B. subtilis mediates the first contact with the roots. These cells differentiate into biofilm-producing cells only several hours after the bacteria first contact the root. Our study reveals that intact chemotaxis machinery is required for the bacteria to reach the

  4. Prognostic value of pro-inflammatory cytokine and pro-angiogenesis factor in differentiating malignant from benign exudative effusion.

    Science.gov (United States)

    Elhefny, Radwa Ahmed; Shaban, Marwa Moawad; Shaker, Olfat Gamil

    2017-01-01

    The precise mechanism of pathogenesis in exudation of effusions is uncertain. Released factors in inflammation and malignancy of pleura are related to incremented permeability of the micro-pleural vessels. Angiopoietins (Ang) take part in development of angiogenesis and pleural inflammation. Interleukin-8 (IL-8) influences proliferation and tumor angiogenesis and it is expressed in cancer. The aims of this study were to investigate the relationship between inflammation, angiogenesis and etiologies of exudative effusions, and to evaluate the diagnostic value in differentiating malignant from benign. The study includes 49 pleural fluid (PF) samples. Ang-2 and IL-8 in PF and serum were estimated. Ten patients were transudative and 39 patients were exudative fluid, subdivided into 16 benign and 23 malignant effusion. Ang-2 and IL-8 either fluid level or ratio were in significantly high in exudative more than in transudative fluid (P = 0.002). Ang-2 and IL-8 in PF were in high level than in serum of exudative and transudative. Ang-2 fluid level and ratio were significantly high in benign exudative effusion (P = 0.01, P = 0.05, respectively), while IL-8 level was significantly high in malignant exudative effusion (P = 0.04). Cut-off points for PF Ang-2 and IL-8 in differentiating malignant from benign exudative were 15.67 ng/mL, 325.54 pg/mL, respectively. Our results support the evidence that angiogenesis and inflammatory pathways are linked, and that inflammation and vascular permeability of pleura constitutes the pathogenic basis of the majority of exudative effusion. © 2015 John Wiley & Sons Ltd.

  5. Studies on the pathogenesis of fever. III. The leucocytic origin of endogenous pyrogen in acute inflammatory exudates.

    Science.gov (United States)

    KING, M K; WOOD, W B

    1958-02-01

    The evolution of an acute inflammatory exudate produced in rabbits by the intraperitoneal injection of saline has been described. Evidence has been presented that polymorphonuclear leucocytes release endogenous pyrogen into the cell-free fluid of the exudate. Leucocytes from such exudates have also been shown to release pyrogen into the surrounding medium during incubation in vitro at 37 degrees C. The results of parallel cytological studies have provided evidence which suggests that the leucocytes give up their pyrogen while functionally intact. These observations add further support to the hypothesis that polymorphonuclear leucocytes play a significant role in the pathogenesis of fever.

  6. Jasmonic Acid Enhances Al-Induced Root Growth Inhibition.

    Science.gov (United States)

    Yang, Zhong-Bao; He, Chunmei; Ma, Yanqi; Herde, Marco; Ding, Zhaojun

    2017-02-01

    Phytohormones such as ethylene and auxin are involved in the regulation of the aluminum (Al)-induced root growth inhibition. Although jasmonate (JA) has been reported to play a crucial role in the regulation of root growth and development in response to environmental stresses through interplay with ethylene and auxin, its role in the regulation of root growth response to Al stress is not yet known. In an attempt to elucidate the role of JA, we found that exogenous application of JA enhanced the Al-induced root growth inhibition. Furthermore, phenotype analysis with mutants defective in either JA biosynthesis or signaling suggests that JA is involved in the regulation of Al-induced root growth inhibition. The expression of the JA receptor CORONATINE INSENSITIVE1 (COI1) and the key JA signaling regulator MYC2 was up-regulated in response to Al stress in the root tips. This process together with COI1-mediated Al-induced root growth inhibition under Al stress was controlled by ethylene but not auxin. Transcriptomic analysis revealed that many responsive genes under Al stress were regulated by JA signaling. The differential responsive of microtubule organization-related genes between the wild-type and coi1-2 mutant is consistent with the changed depolymerization of cortical microtubules in coi1 under Al stress. In addition, ALMT-mediated malate exudation and thus Al exclusion from roots in response to Al stress was also regulated by COI1-mediated JA signaling. Together, this study suggests that root growth inhibition is regulated by COI1-mediated JA signaling independent from auxin signaling and provides novel insights into the phytohormone-mediated root growth inhibition in response to Al stress. © 2017 American Society of Plant Biologists. All Rights Reserved.

  7. Seedling root targets

    Science.gov (United States)

    Diane L. Haase

    2011-01-01

    Roots are critical to seedling performance after outplanting. Although root quality is not as quick and simple to measure as shoot quality, target root characteristics should be included in any seedling quality assessment program. This paper provides a brief review of root characteristics most commonly targeted for operational seedling production. These are: root mass...

  8. Comparative effectiveness of the methods adenoidectomy in cнildren with exudative otitis media

    Directory of Open Access Journals (Sweden)

    Gusakov A.

    2016-03-01

    Full Text Available Actuality: A thorough sanation of the nasopharynx is essential for successful treatment of the exudative otitis media (EOM. The literature describes in detail the state of the nasopharynx after different types of adenoidectomy. The classifications of the location of the remnants of lymphoid tissue and the extent of scarring in the nasopharynx are given.The subject of this work is to trace the relationship of postoperative nasopharyngeal changes with recurrent EOM. Objective: To study the immediate and long-term results of different methods of surgical treatment of hypertrophy of the nasopharyngeal lymphoid tissue in children with exudative otitis media. Materials and Methods: This paper presents information on the results of treatment of 62 children of 5–7 years suffering from exudative otitis media. Observations were carried out in two groups of patients. The first group included 28 children previously undergone adenoidectomy, with the signs of recurrent exudative otitis. The second group included 34 children with exudative otitis previously untreated surgically. The task of the investigation is to study the effectiveness of endonasal and extranasal methods of surgical removal of nasopharengeal lymphoid tissue with a minimum probability of scar obliteration of the mouth of the Eustachian tube. Results and discussion: The priority method in nasopharengeal surgery in children is extranasal access with shaver technology in conjunction with cold plasma surgery. The using of these methods gives a clear visualization of the operating field under conditions of moderately bleeding wound. On the other hand, endonasal approach is associated with traumatization of the nasal mucosa with incomplete volume visualization of the surgical field. This combination can result in a longer healing of the surgical wound, the formation of adhesions of the nasal cavity and scarring in the nasopharynx. Complete visualization of the operating field significantly

  9. Mechanisms of salt tolerance in habanero pepper plants (Capsicum chinense Jacq.): Proline accumulation, ions dynamics and sodium root-shoot partition and compartmentation.

    Science.gov (United States)

    Bojórquez-Quintal, Emanuel; Velarde-Buendía, Ana; Ku-González, Angela; Carillo-Pech, Mildred; Ortega-Camacho, Daniela; Echevarría-Machado, Ileana; Pottosin, Igor; Martínez-Estévez, Manuel

    2014-01-01

    Despite its economic relevance, little is known about salt tolerance mechanisms in pepper plants. To address this question, we compared differences in responses to NaCl in two Capsicum chinense varieties: Rex (tolerant) and Chichen-Itza (sensitive). Under salt stress (150 mM NaCl over 7 days) roots of Rex variety accumulated 50 times more compatible solutes such as proline compared to Chichen-Itza. Mineral analysis indicated that Na(+) is restricted to roots by preventing its transport to leaves. Fluorescence analysis suggested an efficient Na(+) compartmentalization in vacuole-like structures and in small intracellular compartments in roots of Rex variety. At the same time, Na(+) in Chichen-Itza plants was compartmentalized in the apoplast, suggesting substantial Na(+) extrusion. Rex variety was found to retain more K(+) in its roots under salt stress according to a mineral analysis and microelectrode ion flux estimation (MIFE). Vanadate-sensitive H(+) efflux was higher in Chichen-Itza variety plants, suggesting a higher activity of the plasma membrane H(+)-ATPase, which fuels the extrusion of Na(+), and, possibly, also the re-uptake of K(+). Our results suggest a combination of stress tolerance mechanisms, in order to alleviate the salt-induced injury. Furthermore, Na(+) extrusion to apoplast does not appear to be an efficient strategy for salt tolerance in pepper plants.

  10. Dynamics of nitrification and denitrification in root- oxygenated sediments and adaptation of ammonia-oxidizing bacteria to low-oxygen or anoxic habitats

    NARCIS (Netherlands)

    Bodelier, P.L.E.; Libochant, J.A.; Blom, C.W.P.M.; Laanbroek, H.J.

    1996-01-01

    Oxygen-releasing plants may provide aerobic niches in anoxic sediments and soils for ammonia-oxidizing bacteria, The oxygen- releasing, aerenchymatous emergent macrophyte Glycerin maxima had a strong positive effect on numbers and activities of the nitrifying bacteria in its root zone in spring and

  11. Dynamics of nitrification and denitrification in root- oxygenated sediments and adaptation of ammonia-oxidizing bacteria to low-oxygen or anoxic habitats

    NARCIS (Netherlands)

    Bodelier, P.L.E.; Libochant, J.A.; Blom, C.W.P.M.; Laanbroek, H.J.

    1996-01-01

    Oxygen-releasing plants may provide aerobic niches in anoxic sediments and soils for ammonia-oxidizing bacteria. The oxygen-releasing, aerenchymatous emergent macrophyte Glyceria maxima had a strong positive effect on numbers and activities of the nitrifying bacteria in its root zone in spring and

  12. Application of biochar reduces Ralstonia solanacearum infection via effects on pathogen chemotaxis, swarming motility, and root exudate adsorption

    NARCIS (Netherlands)

    Gu, Yian; Hou, Yugang; Huang, Dapeng; Hao, Zhexia; Wang, Xiaofang; Wei, Zhong; Jousset, Alexandre; Tan, Shiyong; Xu, Dabing; Shen, Qirong; Xu, Yangchun; Friman, Ville Petri

    Aims: We evaluated the efficacy of biochar application for suppressing bacterial wilt of tomato and identified the potential underlying mechanisms involved in the disease control. Methods: We measured the impact of two different sized biochar (53–120 μm and 380–830 μm) on bacterial wilt incidence in

  13. Novel weapons and invasion: biogeographic differences in the competitive effects of Centaurea maculosa and its root exudate (+/-)-catechin.

    Science.gov (United States)

    He, Wei-Ming; Feng, Yulong; Ridenour, Wendy M; Thelen, Giles C; Pollock, Jarrod L; Diaconu, Alecu; Callaway, Ragan M

    2009-04-01

    Recent studies suggest that the invasive success of Centaurea maculosa may be related to its stronger allelopathic effects on native North American species than on related European species, one component of the "novel weapons" hypothesis. Other research indicates that C. maculosa plants from the invasive range in North America have evolved to be larger and better competitors than conspecifics from the native range in Europe, a component of the "evolution of increased competitive ability" hypothesis. These hypotheses are not mutually exclusive, but this evidence sets the stage for comparing the relative importance of evolved competitive ability to inherent competitive traits. In a competition experiment with a large number of C. maculosa populations, we found no difference in the competitive effects of C. maculosa plants from North America and Europe on other species. However, both North American and European C. maculosa were much better competitors against plants native to North America than congeners native to Romania, collected in areas where C. maculosa is also native. These results are consistent with the novel weapons hypothesis. But, in a second experiment using just one population from North America and Europe, and where North American and European species were collected from a broader range of sites, competitive interactions were weaker overall, and the competitive effects of C. maculosa were slightly stronger against European species than against North American species. Also consistent with the novel weapons hypothesis, (+/-)-catechin had stronger effects on native North American species than on native European species in two experiments. Our results suggest that the regional composition of the plant communities being invaded by C. maculosa may be more important for invasive success than the evolution of increased size and competitive ability.

  14. Can liming reduce cadmium (Cd) accumulation in rice (Oryza sativa) in slightly acidic soils? A contradictory dynamic equilibrium between Cd uptake capacity of roots and Cd immobilisation in soils.

    Science.gov (United States)

    Yang, Yongjie; Chen, Jiangmin; Huang, Qina; Tang, Shaoqing; Wang, Jianlong; Hu, Peisong; Shao, Guosheng

    2018-02-01

    Cadmium (Cd) accumulation in rice is strongly controlled by liming, but information on the use of liming to control Cd accumulation in rice grown in slightly acidic soils is inconsistent. Here, pot experiments were carried out to investigate the mechanisms of liming on Cd accumulation in two rice varieties focusing on two aspects: available/exchangeable Cd content in soils that were highly responsive to liming, and Cd uptake and transport capacity in the roots of rice in terms of Cd accumulation-relative gene expression. The results showed that soil availability and exchangeable iron, manganese, zinc and Cd contents decreased with increased liming, and that genes related to Cd uptake (OsNramp5 and OsIRT1) were sharply up-regulated in the roots of the two rice varieties. Thus, iron, manganese, zinc and Cd contents in rice plants increased under low liming applications but decreased in response to high liming applications. However, yield and rice quantities were only slightly affected. These results indicated that Cd accumulation in rice grown in slightly acidic soils presents a contradictory dynamic equilibrium between Cd uptake capacity by roots and soil Cd immobilisation in response to liming. The enhanced Cd uptake capacity under low liming dosages increases risks to human health. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Lateral root organogenesis - from cell to organ.

    Science.gov (United States)

    Benková, Eva; Bielach, Agnieszka

    2010-12-01

    Unlike locomotive organisms capable of actively approaching essential resources, sessile plants must efficiently exploit their habitat for water and nutrients. This involves root-mediated underground interactions allowing plants to adapt to soils of diverse qualities. The root system of plants is a dynamic structure that modulates primary root growth and root branching by continuous integration of environmental inputs, such as nutrition availability, soil aeration, humidity, or salinity. Root branching is an extremely flexible means to rapidly adjust the overall surface of the root system and plants have evolved efficient control mechanisms, including, firstly initiation, when and where to start lateral root formation; secondly lateral root primordia organogenesis, during which the development of primordia can be arrested for a certain time; and thirdly lateral root emergence. Our review will focus on the most recent advances in understanding the molecular mechanisms involved in the regulation of lateral root initiation and organogenesis with the main focus on root system of the model plant Arabidopsis thaliana. Copyright © 2010 Elsevier Ltd. All rights reserved.

  16. Total antioxidant potential of resinous exudates from Heliotropium species, and a comparison of the ABTS and DPPH methods.

    Science.gov (United States)

    Lissi, E A; Modak, B; Torres, R; Escobar, J; Urzua, A

    1999-06-01

    Total reactive antioxidant potential (TRAP) of resinous exudates from Heliotropium species was evaluated by measuring the bleaching of stable free radicals. The antioxidant capacity of the resinous exudates in Trolox equivalents, evaluated from the bleaching of ABTS derived radical cations, ranged from 2.0 M (H. huascoense) to 5.2 M (H. stenophyllum), indicating a very high concentration of phenolic compounds. Considerably smaller values were obtained by measuring the bleaching of DPPH radicals. The ratio between the values obtained employing ABTS derived radicals and DPPH, ranged from 37 (H. megalanthum) to 4.5 (H. chenopodiaceum variety typica). The magnitude of the difference can be considered as an indication of the relative reactivity of the antioxidants present in the exudates. Similar ratios were observed when stoichiometric coefficients were evaluated for representative purified flavonoids obtained from the resinous exudates.

  17. ZNF408 is mutated in familial exudative vitreoretinopathy and is crucial for the development of zebrafish retinal vasculature

    NARCIS (Netherlands)

    Collin, R.W.J.; Nikopoulos, K.; Dona, M.A.; Gilissen, C.F.H.A.; Hoischen, A.; Boonstra, F.N.; Poulter, J.A.; Kondo, H.; Berger, W.; Toomes, C.; Tahira, T.; Mohn, L.R.; Blokland, E.A.W.; Hetterschijt, L.; Ali, M.; Groothuismink, J.M.; Duijkers, L.E.M.; Inglehearn, C.F.; Sollfrank, L.; Strom, T.M.; Uchio, E.; Nouhuys, C.E. van; Kremer, H.; Veltman, J.A.; Wijk, E. van; Cremers, F.P.M.

    2013-01-01

    Familial exudative vitreoretinopathy (FEVR) is a genetically heterogeneous disorder characterized by abnormal vascularization of the peripheral retina, which can result in retinal detachment and severe visual impairment. In a large Dutch FEVR family, we performed linkage analysis, exome sequencing,

  18. Correlation between organic acid exudation and metal uptake by ectomycorrhizal fungi grown on pond ash in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Ray, P.; Adholeya, A. [Energy & Resources Institute, New Delhi (India). India Habitat Centre

    2009-04-15

    Experiments were conducted to investigate the effect of coal ash on organic acid exudation and subsequent metal uptake by ectomycorrhizal fungi. Four isolates of ectomycorrhizal fungi namely, Pisolithus tinctorius (EM-1293 and EM-1299), Scleroderma verucosum (EM-1283) and Scleroderma cepa (EM-1233) were grown on pond ash moistened with Modified Melin-Norkans medium in vitro. Exudation of formic acid, malic acid and succinic acid by these fungi were detected by HPLC. Mycelial accumulation of Al, As, Cd, Cr, Ni and Pb by these fungi was assayed by atomic absorption spectrophotometer. Relationship between organic acid exudation and metal uptake was determined using classical multivariate linear regression model. Correlation between organic acid exudation and metal uptake could be substantiated when several metals are considered collectively. The finding supports the widespread role of low molecular weight organic acid as a function of tolerance, when exposed to metals in vitro.

  19. Lactoferrin, myeloperoxidase, lysozyme and eosinophil cationic protein in exudate in delayed type hypersensitivity

    DEFF Research Database (Denmark)

    Lerche, A; Bisgaard, H; Christensen, J D

    1988-01-01

    allergic patients with nickel challenge in the chamber medium showed a time-dependent increase of mononuclear cells, eosinophils and basophils and a concomitant decrease of polymorphonuclear granulocytes, characteristic of a combined specific and unspecific inflammation. The morphology of the exudate...... in contact allergic patients exposed to nickel showed a dominance of polymorphonuclear granulocytes throughout the study period, while mononuclear cells, eosinophils and basophils were detected at a much lower quantity and with a considerable delay. Further, we studied the kinetics of the leucocyte granule...... proteins: lactoferrin, myeloperoxidase, lysozyme and eosinophil cationic protein in exudate fluid in a parallel test. A significant higher flux was found for all during the second day of allergen exposure compared to contact allergic patients without allergen challenge as well as normal volunteers...

  20. Heliolactone, a non-sesquiterpene lactone germination stimulant for root parasitic weeds from sunflower.

    Science.gov (United States)

    Ueno, Kotomi; Furumoto, Toshio; Umeda, Shuhei; Mizutani, Masaharu; Takikawa, Hirosato; Batchvarova, Rossitza; Sugimoto, Yukihiro

    2014-12-01

    Root exudates of sunflower (Helianthus annuus L.) line 2607A induced germination of seeds of root parasitic weeds Striga hermonthica, Orobanche cumana, Orobanche minor, Orobanche crenata, and Phelipanche aegyptiaca. Bioassay-guided purification led to the isolation of a germination stimulant designated as heliolactone. FT-MS analysis indicated a molecular formula of C20H24O6. Detailed NMR spectroscopic studies established a methylfuranone group, a common structural component of strigolactones connected to a methyl ester of a C14 carboxylic acid via an enol ether bridge. The cyclohexenone ring is identical to that of 3-oxo-α-ionol and the other part of the molecule corresponds to an oxidized carlactone at C-19. It is a carlactone-type molecule and functions as a germination stimulant for seeds of root parasitic weeds. Heliolactone induced seed germination of the above mentioned root parasitic weeds, while dehydrocostus lactone and costunolide, sesquiterpene lactones isolated from sunflower root exudates, were effective only on O. cumana and O. minor. Heliolactone production in aquacultures increased when sunflower seedlings were grown hydroponically in tap water and decreased on supplementation of the culture with either phosphorus or nitrogen. Costunolide, on the other hand, was detected at a higher concentration in well-nourished medium as opposed to nutrient-deficient media, thus suggesting a contrasting contribution of heliolactone and the sesquiterpene lactone to the germination of O. cumana under different soil fertility levels. Copyright © 2014 Elsevier Ltd. All rights reserved.

  1. The role of prophylactic ibuprofen and N-acetylcysteine on the level of cytokines in periapical exudates and the post-treatment pain

    Directory of Open Access Journals (Sweden)

    Ehsani Maryam

    2012-09-01

    Full Text Available Abstract Background Periapical lesions are inflammatory diseases that result in periapical bone destruction because of host defensive–microbial disturbances. Objective To evaluate the role of prophylactic ibuprofen and N-acetylcysteine (NAC on the levels of tumor necrosis factor alpha (TNF- α, interleukin- 6(IL-6 and IL-17 and post-treatment pain level in chronic periapical lesions. Materials and methods Eighty patients with chronic apical lesions less than 1 cm were randomly assigned to receive NAC tablets (400 mg, ibuprofen tablets (400 mg, NAC (400 mg/ibuprofen (200 mg combination and placebo 90 minutes prior to sampling. Periapical exudates were collected from root canals. TNF- α, IL-6 and IL-17 levels were determined by ELISA and post-treatment pain was assessed using a visual analog scale (VAS. Results There was a significant difference in IL-6 level between ibuprofen group and placebo (p = 0.019. Significant difference in IL-17 level was observed between NAC/ibuprofen combination group and placebo (p = 0.043. Four hours after treatment, a significant difference was observed in VAS pain score between ibuprofen group and placebo (p = 0.017. Eight hours post-treatment, VAS pain score for NAC group was statistically lower than placebo group (p = 0.033. After 12 hours VAS pain score showed a significant decrease in NAC group compared to placebo (p = 0.049. Conclusion The prophylactic ibuprofen and NAC failed to clearly reflect their effect on cytokines levels in exudates of chronic periapical lesions. On the other hand it seems that NAC can be a substitute for ibuprofen in the management of post endodontic pain.

  2. The Role of Prophylactic Ibuprofen and N-Acetylcysteine on the Level of Cytokines in Periapical Exudates and the Post-Treatment Pain

    Directory of Open Access Journals (Sweden)

    Seyyed Mohsen Aghajanpour Mir

    2012-09-01

    Full Text Available Background Periapical lesions are inflammatory diseases that result in periapical bone destruction because of host defensive-microbial disturbances. Objective:To evaluate the role of prophylactic ibuprofen and N-acetylcysteine (NAC on the levels of tumor necrosis factor alpha (TNF- alpha, interleukin- 6(IL-6 and IL-17 and post-treatment pain level in chronic periapical lesions. Materials and methods Eighty patients with chronic apical lesions less than 1 cm were randomly assigned to receive NAC tablets (400 mg, ibuprofen tablets (400 mg, NAC (400 mg/ibuprofen (200 mg combination and placebo 90 minutes prior to sampling. Periapical exudates were collected from root canals. TNF- alpha, IL-6 and IL-17 levels were determined by ELISA and posttreatment pain was assessed using a visual analog scale (VAS. Results:There was a significant difference in IL-6 level between ibuprofen group and placebo (p = 0.019. Significant difference in IL-17 level was observed between NAC/ibuprofen combination group and placebo (p = 0.043. Four hours after treatment, a significant difference was observed in VAS pain score between ibuprofen group and placebo (p = 0.017. Eight hours post-treatment, VAS pain score for NAC group was statistically lower than placebo group (p = 0.033. After 12 hours VAS pain score showed a significant decrease in NAC group compared to placebo (p = 0.049. Conclusion:The prophylactic ibuprofen and NAC failed to clearly reflect their effect on cytokines levels in exudates of chronic periapical lesions. On the other hand it seems that NAC can be a substitute for ibuprofen in the management of post endodontic pain

  3. Exudate Chemical Profiles Derived from Lespedeza and Other Tallgrass Prairie Plant Species

    Science.gov (United States)

    2017-05-01

    Chemical Profiles Derived from Lespedeza and Other Tall- grass Prairie Plant Species. ERDC TN-17-1. Vicksburg, MS: U.S. Army Engineer Re- search and...200-1-52. Washington, DC: U.S. Army Corps of Engineers Headquarters, Civil Works. https://www.wbdg.org/ffc/army-coe/public-works-technical-bulletins...ERDC TN-17-1 May 2017 Approved for public release; distribution is unlimited. Exudate Chemical Profiles Derived from Lespedeza and Other

  4. Neurogenic plasma exudation mediates grain dust-induced tissue injury in vivo.

    Science.gov (United States)

    Gao, X P; Von Essen, S; Rubinstein, I

    1997-02-01

    The purpose of this study was to determine whether an aqueous extract of grain sorghum dust (GDE) elicits neurogenic plasma exudation in the oral mucosa in vivo. Using intravital microscopy, we found that GDE elicited significant, concentration-dependent leaky site formation and an increase in clearance of fluorescein isothiocyanate-labeled dextran (FITC-dextran; mol mass 70 kDa) from the hamster cheek pouch (P grain sorghum dust elicits immediate oral mucosa inflammation in vivo.

  5. Functional properties of PSE (Pale, Soft, Exudative) broiler meat in the production of mortadella

    OpenAIRE

    Kissel,Cassiana; Soares,Adriana Lourenço; Rossa,Alessandro; Shimokomaki,Massami

    2009-01-01

    This work was carried out in order to evaluate whether the functional properties of broiler meat are affected by the factors that lead to PSE (Pale, Soft, Exudative). PSE meat was characterized by pH and L* values, and mortadella formulations consisted of isolated soy protein, sodium tripolyphosphate, and cassava starch in addition to PSE and normal meats. The functionality of the meat was evaluated by examining the water holding capacity (WHC), texture profile, emulsion stability (ES) and co...

  6. Isothermal titration calorimetric and computational studies on the binding of chitooligosaccharides to pumpkin (Cucurbita maxima) phloem exudate lectin.

    Science.gov (United States)

    Narahari, Akkaladevi; Singla, Hitesh; Nareddy, Pavan Kumar; Bulusu, Gopalakrishnan; Surolia, Avadhesha; Swamy, Musti J

    2011-04-14

    The interaction of chitooligosaccharides [(GlcNAc)(2-6)] with pumpkin phloem exudate lectin (PPL) was investigated by isothermal titration calorimetry and computational methods. The dimeric PPL binds to (GlcNAc)(3-5) with binding constants of 1.26-1.53 × 10(5) M(-1) at 25 °C, whereas chitobiose exhibits approximately 66-fold lower affinity. Interestingly, chitohexaose shows nearly 40-fold higher affinity than chitopentaose with a binding constant of 6.16 × 10(6) M(-1). The binding stoichiometry decreases with an increase in the oligosaccharide size from 2.26 for chitobiose to 1.08 for chitohexaose. The binding reaction was essentially enthalpy driven with negative entropic contribution, suggesting that hydrogen bonds and van der Waals' interactions are the main factors that stabilize PPL-saccharide association. The three-dimensional structure of PPL was predicted by homology modeling, and binding of chitooligosaccharides was investigated by molecular docking and molecular dynamics simulations, which showed that the protein binding pocket can accommodate up to three GlcNAc residues, whereas additional residues in chitotetraose and chitopentaose did not exhibit any interactions with the binding pocket. Docking studies with chitohexaose indicated that the two triose units of the molecule could interact with different protein binding sites, suggesting formation of higher order complexes by the higher oligomers of GlcNAc by their simultaneous interaction with two protein molecules.

  7. Effect of gum tragacanth exuded by three Iranian Astragalus on mixed milk protein system during acid gelation.

    Science.gov (United States)

    Nejatian, Mohammad; Hatami, Masoud; Mohammadifar, Mohammad Amin

    2013-02-01

    The effects of various concentrations of three species of gum tragacanth on the gelation process, microstructure and viscoelastic properties of milk protein mixed gels acidified at 37°C by glucono-δ-lactone (GDL) were investigated using dynamic rheometry and microscopy. According to rheological measurements, the addition of gum tragacanth in the range of 0.05-0.2% (w/w) into milk protein dispersions led to a weaker structure for the milk protein network, compared to the control sample. This weakening effect could be eliminated by adding 0.3% (w/w) gum tragacanth exudates from A. gossypinus; the compositional features of gum tragacanth may have been responsible for the improved protein-protein interactions, greater structural strength and reduced gelation time onset. It was determined by scanning electron microscopy that the addition of gum tragacanth at a low concentration caused the density of the matrix to increase, while an open structure was observed in the presence of a higher gum concentration. Copyright © 2012 Elsevier B.V. All rights reserved.

  8. Raise of efficiency of flocculation-precipitation treatment of exuding water from reclaimed land by irradiation

    International Nuclear Information System (INIS)

    Sawai, Teruko; Yamazaki, Masao; Sawai, Takeshi

    1984-01-01

    When rain falls on the coastal reclaimed land filled with home garbage in Tokyo, a large quantity of water containing much organic contaminant flows out. It is difficult to treat this water exuding from reclaimed land by conventional method. Because the water with low BOD which is difficult to treat by biological process flows out for long period after the stabilization of reclaimed land. When the water is treated by flocculation and precipitation, the substances with high molecular weight are easily removed, but the rate of removal of fulvic acid with low molecular weight, which accounts for more than 60% of the composition of the water, is very poor. Therefore, it was examined to change the fulvic acid to high molecular weight by irradiation, and to improve the efficiency of the flocculation-precipitation treatment of exuding water. Exuding water was sampled in Tokyo Bay No.15 reclaimed land, and it was separated into humic acid and fulvic acid. The Co-60 gamma ray of 5 kCi was irradiated to the samples. The experimental method and the results are reported. The change of fulvic acid to high molecular weight by irradiation was most efficient at pH 2.2. More than 90% of organic contaminants was able to be removed. (Kako, I.)

  9. Role of blind closed pleural biopsy in the managment of pleural exudates.

    Science.gov (United States)

    Pereyra, Marco F; San-José, Esther; Ferreiro, Lucía; Golpe, Antonio; Antúnez, José; González-Barcala, Francisco-Javier; Abdulkader, Ihab; Álvarez-Dobaño, José M; Rodríguez-Núñez, Nuria; Valdés, Luis

    2013-01-01

    The performance of blind closed pleural biopsy (BCPB) in the study of pleural exudates is controversial. To assess the diagnostic yield of BCPB in clinical practice and its role in the study of pleural exudates. Data were retrospectively collected on all patients who underwent BCPB performed between January 1999 and December 2011. A total of 658 BCPBs were performed on 575 patients. Pleural tissue was obtained in 590 (89.7%) of the biopsies. A malignant pleural effusion was found in 35% of patients. The cytology and the BCPB were positive in 69.2% and 59.2% of the patients, respectively. Of the patients with negative cytology, 21 had a positive BCPB (diagnostic improvement, 15%), which would have avoided one pleuroscopy for every seven BCPBs that were performed. Of the 113 patients with a tuberculous effusion, granulomas were observed in 87 and the Lowenstein culture was positive in an additional 17 (sensitivity 92%). The overall sensitivity was 33.9%, with a specificity and positive predictive value of 100%, and a negative predictive value of 71%. Complications were recorded in 14.4% of patients (pneumothorax 9.4%; chest pain 5.6%; vasovagal reaction, 4.1%; biopsy of another organ 0.5%). BCPB still has a significant role in the study of a pleural exudate. If an image-guided technique is unavailable, it seems reasonable to perform BCPB before resorting to a pleuroscopy. These results support BCPB as a relatively safe technique.

  10. ACUTE EXUDATIVE PARANEOPLASTIC POLYMORPHOUS VITELLIFORM MACULOPATHY DURING VEMURAFENIB AND PEMBROLIZUMAB TREATMENT FOR METASTATIC MELANOMA.

    Science.gov (United States)

    Sandhu, Harpal S; Kolomeyer, Anton M; Lau, Marisa K; Shields, Carol L; Schuchter, Lynn M; Nichols, Charles W; Aleman, Tomas S

    2017-06-13

    To describe a patient with BRAF mutation-positive cutaneous melanoma who developed acute exudative polymorphous vitelliform maculopathy during vemurafenib and pembrolizumab treatment for metastatic melanoma. Retrospective case report documented with wide-field fundus imaging, spectral domain optical coherence tomography, and fundus autofluorescence imaging. A 55-year-old woman with bilateral ductal breast carcinoma and BRAF mutation-positive metastatic cutaneous melanoma complained of bilateral blurred vision within 5 days of starting vemurafenib (BRAF inhibitor). She had been on pembrolizumab (program death receptor antibody) and intermittently on dabrafenib (BRAF inhibitor) and trametinib (MEK inhibitor), and had a normal ophthalmologic examination. On presentation three weeks after the introduction of vemurafenib, her visual acuity had declined to 20/40 in both eyes. Her examination showed diffuse elevation of the fovea with multifocal yellow-white, crescent-shaped subretinal deposits within the macula of both eyes and bilateral neurosensory retinal detachments by spectral domain optical coherence tomography. Discontinuation of vemurafenib and introduction of difluprednate and dorzolamide led to a gradual resolution (over four months) of the neurosensory detachments with recovery of vision. This case report suggests that acute exudative polymorphous vitelliform maculopathy may be directly associated with the use of BRAF inhibitors as treatment for metastatic cutaneous melanoma, or indirectly by triggering autoimmune-paraneoplastic processes. Future identification of similar associations is required to unequivocally link vemurafenib and/or pembrolizumab to acute exudative polymorphous vitelliform maculopathy in metastatic melanoma.

  11. Outcome of ultrasound-guided small-bore catheter drainage in exudative pleural effusions.

    Science.gov (United States)

    Kiranantawat, Nantaka; Sungsiri, Jitpreedee; Geater, Sarayut L

    2014-05-01

    To evaluate the outcome and safety of ultrasound-guided percutaneous catheter drainage of exudative pleural effusion. The present study was a retrospective analysis of 412 pleural effusions from 373 patients that underwent ultrasound-guided small-bore catheter drainage in exudative pleural effusions between 2004 and 2009. The two most common causes for drainage were parapneumonic effusion or empyema (52.2%) and malignant effusion (30.3%), while the remains were trauma, iatrogenic, and others. Overall clinical success rate was 76.5%. The success rate was lower among malignant pleural effusion (p = 0.003). Causes of effusion were the only independent predictors related to success. Only five (1.2%) patients developed complication during the procedure. Seventy-five of 412 effusions (15.8%) developed complication during the period of drainage; the majority were drain blockage (9%) and accidental dislodgment (4.1%). Ultrasound-guided small-bore catheter drainage was a safe and efficient procedure for exudative pleural effusions.

  12. Thermochemical Properties of Hydrophilic Polymers from Cashew and Khaya Exudates and Their Implications on Drug Delivery

    Directory of Open Access Journals (Sweden)

    Emmanuel O. Olorunsola

    2016-01-01

    Full Text Available Characterization of a polymer is essential for determining its suitability for a particular purpose. Thermochemical properties of cashew gum (CSG extracted from exudates of Anacardium occidentale L. and khaya gum (KYG extracted from exudates of Khaya senegalensis were determined and compared with those of acacia gum BP (ACG. The polymers were subjected to different thermal and chemical analyses. Exudates of CSG contained higher amount of hydrophilic polymer. The pH of 2% w/v gum dispersions was in the order KYG < CSG < ACG. Calcium was the predominant ion in CSG while potassium was predominant in KYG. The FTIR spectra of CSG and KYG were similar and slightly different from that of ACG. Acacia and khaya gums exhibited the same thermal behaviour which is different from that of CSG. X-ray diffraction revealed that the three gums are the same type of polymer, the major difference being the concentration of metal ions. This work suggests the application of cashew gum for formulation of basic and oxidizable drugs while using khaya gum for acidic drugs.

  13. Phytochemical screening of the exudate of Aloe otallensis and its effect on Leishmania donovani

    Directory of Open Access Journals (Sweden)

    Zerihun Tesfaye Nigusse

    2016-06-01

    Full Text Available Objective: To evaluate the antileishmanial activity of methanolic extract of Aloe otallensis (A. otallensis on the promastigote stage of Leishmania donovani (L. donovani as compared to standard drugs and to screen its phytochemical constituents. Methods: Phytochemical screening was done by using the method mentioned by Evans and Trease on methanolic extract of the exudates of Aloe otallensis leaves. The extract was also evaluated for in vitro antileishmanial activity against L. donavani which is found from the Parasitology Unit of Black Lion Hospital. The result was compared to standard drugs of sodium stibogluconate, milfostin and paramomycin. Results: The extract has a good antileishmanial activity with an IC50 of 0.1230 μg/mL on L. donovani (AM 563. The experimental data showed that relatively it had better activity than paramomycin and milfostin but less activity than sodium stibogluconate. The data analyses were done by GraphPad Prism version 5 software after it was read by ELISA reader at the wave length of 650 nm. The phytochemical screening of the exudates of A. otallensis showed the presence of phenol, alkaloid and saponin. Conclusions: The methanol extract of the exudates of A. otallensis has a good antileishmaniasis activity and this may be attributed to phenol, alkaloid and saponin present in the plant. But it needs further analysis for the conformation of which constituent presents in high concentration to know which one has the strongest effect.

  14. Retreatment of Exudative Age-Related Macular Degeneration after Loading 3-Monthly Intravitreal Ranibizumab.

    Science.gov (United States)

    Sugiyama, Atsushi; Sakurada, Yoichi; Honda, Shigeru; Miki, Akiko; Matsumiya, Wataru; Yoneyama, Seigo; Kikushima, Wataru; Iijima, Hiroyuki

    2018-01-01

    The aim of this study was to investigate the clinical implications of required retreatment after 3-monthly intravitreal ranibizumab (IVR) injections followed by as-needed reinjections up to 5 years in eyes with exudative age-related macular degeneration (AMD). A retrospective cohort study was conducted for 165 treatment-naïve eyes from 165 patients with exudative AMD. Visual changes were investigated in terms of the required retreatments. Retreatment-free proportions were 37.0, 23.7, 16.6, 12.1, and 10.5% at 12, 24, 36, 48, and 60 months, respectively. Visual changes were significantly better in eyes which did not require retreatment at every yearly checkpoint within the 5 years. A multivariate logistic regression analysis revealed that requirement of additional IVR treatments in the first 12-24 months was associated with the T allele (risk allele) of ARMS2 A69S (p = 0.010 and 0.015, respectively). Cox regression analysis revealed that older age (p = 0.046) and the T allele of ARMS2 A69S (p = 0.036) were associated with required retreatment within the 5-year follow-up period. Age and the T allele of ARMS2 A69S are the risk factors requiring retreatments, leading to poor visual change in eyes with exudative AMD following the initial 3-monthly IVR. © 2017 S. Karger AG, Basel.

  15. Patterns of organic acids exuded by pioneering fungi from a glacier forefield are affected by carbohydrate sources

    Science.gov (United States)

    Brunner, Ivano; Goren, Asena; Schlumpf, Alessandro

    2014-01-01

    Bare soils in the area of retreating glaciers are ideal environments to study the role of microorganisms in the early soil formation and in processes of mineral weathering. The aim of our study was to investigate whether the source of carbohydrate would influence the patterns of organic acids exuded by fungal species. Three pioneering fungus species, isolated from fine granitic sediments in front of the Damma glacier from the central Swiss Alps, have previously been found to have the capability to exude organic acids and dissolve granite powder. In batch experiments, various carbohydrates, including glucose, cellulose, pectin, pollen, and cell remnants of cyanobacteria, fungi, and algae, were applied as carbohydrate sources and the patterns of exuded organic acids recorded. The results showed that two fungi, the zygomycete fungus Mucor hiemalis and the ascomycete fungus Penicillium chrysogenum, released a significantly higher amount of organic acids in dependence on specific carbohydrate sources. Pollen and algae as carbohydrate sources triggered significantly the exudation of malate in M. hiemalis, and pollen and cellulose that of oxalate in P. chrysogenum. We conclude that the occurrence of complex carbohydrate sources in nutrient-deficient deglaciated soils may positively influence the exudation of organic acids of fungi. In particular, pollen and remnants of other microorganisms can trigger the exudation of organic acids of fungi in order to promote the weathering of minerals and to make nutrients available that would otherwise be trapped in that cryospheric environment.

  16. Patterns of organic acids exuded by pioneering fungi from a glacier forefield are affected by carbohydrate sources

    International Nuclear Information System (INIS)

    Brunner, Ivano; Goren, Asena; Schlumpf, Alessandro

    2014-01-01

    Bare soils in the area of retreating glaciers are ideal environments to study the role of microorganisms in the early soil formation and in processes of mineral weathering. The aim of our study was to investigate whether the source of carbohydrate would influence the patterns of organic acids exuded by fungal species. Three pioneering fungus species, isolated from fine granitic sediments in front of the Damma glacier from the central Swiss Alps, have previously been found to have the capability to exude organic acids and dissolve granite powder. In batch experiments, various carbohydrates, including glucose, cellulose, pectin, pollen, and cell remnants of cyanobacteria, fungi, and algae, were applied as carbohydrate sources and the patterns of exuded organic acids recorded. The results showed that two fungi, the zygomycete fungus Mucor hiemalis and the ascomycete fungus Penicillium chrysogenum, released a significantly higher amount of organic acids in dependence on specific carbohydrate sources. Pollen and algae as carbohydrate sources triggered significantly the exudation of malate in M. hiemalis, and pollen and cellulose that of oxalate in P. chrysogenum. We conclude that the occurrence of complex carbohydrate sources in nutrient-deficient deglaciated soils may positively influence the exudation of organic acids of fungi. In particular, pollen and remnants of other microorganisms can trigger the exudation of organic acids of fungi in order to promote the weathering of minerals and to make nutrients available that would otherwise be trapped in that cryospheric environment. (paper)

  17. Dynamics of adventitious rooting in mini-cuttings of Eucalyptus benthamii x Eucalyptus dunnii=Dinamica de enraizamento adventício em miniestacas de Eucalyptus benthamii x Eucalyptus dunnii

    Directory of Open Access Journals (Sweden)

    Antônio Natal Gonçalves

    2012-04-01

    Full Text Available It is possible to determine the optimum time for permanence of vegetative propagules (mini-cuttings inside a greenhouse for rooting, and this value can be used to optimize the structure of the nursery. The aim of this study was to determine the dynamics of adventitious rooting in mini-cuttings of three clones of Eucalyptus benthamii x Eucalyptus dunnii. Sprouts of H12, H19 and H20 clones were collected from mini-stumps that were planted in gutters containing sand and grown in a semi-hydroponic system. The basal region of the mini-cuttings was immersed in 2,000 mg L-1 indole-3-butyric acid (IBA solution for 10 seconds. The rooting percentage of the mini-cuttings, the total length of the root system and the rooting rate per mini-cutting were also evaluated at 0 (time of planting, 7, 14, 21, 28, 35, 42, 49 and 56 days. We used logistic and exponential regression to mathematically model the speed of rhizogenesis. The rooting percentage was best represented as a logistic model, and the total length of the root system was best represented as an exponential model. The clones had different speeds of adventitious rooting. The optimum time for permanence of the mini-cuttings inside the greenhouse for rooting was between 35 and 42 days, and varied depending on the genetic material.O tempo ideal de permanência de propágulos vegetativos (miniestacas no interior da casa de vegetação para a rizogênese é possível de ser determinado matematicamente, o que pode otimizar as instalações do viveiro. O objetivo deste estudo foi determinar a dinâmica de enraizamento de miniestacas de três clones de Eucalyptus benthamii x Eucalyptus dunnii. Brotações dos clones H19, H12 e H20 foram coletadas de minicepas plantadas em canaletão com areia e cultivadas sob sistema semi-hidropônico. A região basal da miniestaca foi imersa em solução de 2.000 mg L-1 de ácido indolbutírico (AIB por 10 segundos. A porcentagem de enraizamento de miniestacas, o comprimento

  18. Hard exudates segmentation based on learned initial seeds and iterative graph cut.

    Science.gov (United States)

    Kusakunniran, Worapan; Wu, Qiang; Ritthipravat, Panrasee; Zhang, Jian

    2018-05-01

    (Background and Objective): The occurrence of hard exudates is one of the early signs of diabetic retinopathy which is one of the leading causes of the blindness. Many patients with diabetic retinopathy lose their vision because of the late detection of the disease. Thus, this paper is to propose a novel method of hard exudates segmentation in retinal images in an automatic way. (Methods): The existing methods are based on either supervised or unsupervised learning techniques. In addition, the learned segmentation models may often cause miss-detection and/or fault-detection of hard exudates, due to the lack of rich characteristics, the intra-variations, and the similarity with other components in the retinal image. Thus, in this paper, the supervised learning based on the multilayer perceptron (MLP) is only used to identify initial seeds with high confidences to be hard exudates. Then, the segmentation is finalized by unsupervised learning based on the iterative graph cut (GC) using clusters of initial seeds. Also, in order to reduce color intra-variations of hard exudates in different retinal images, the color transfer (CT) is applied to normalize their color information, in the pre-processing step. (Results): The experiments and comparisons with the other existing methods are based on the two well-known datasets, e_ophtha EX and DIARETDB1. It can be seen that the proposed method outperforms the other existing methods in the literature, with the sensitivity in the pixel-level of 0.891 for the DIARETDB1 dataset and 0.564 for the e_ophtha EX dataset. The cross datasets validation where the training process is performed on one dataset and the testing process is performed on another dataset is also evaluated in this paper, in order to illustrate the robustness of the proposed method. (Conclusions): This newly proposed method integrates the supervised learning and unsupervised learning based techniques. It achieves the improved performance, when compared with the

  19. On the road to quantitative genetic/genomic analyses of root growth and development components underlying root architecture

    International Nuclear Information System (INIS)

    Draye, X.; Dorlodot, S. de; Lavigne, T.

    2006-01-01

    The quantitative genetic and functional genomic analyses of root development, growth and plasticity will be instrumental in revealing the major regulatory pathways of root architecture. Such knowledge, combined with in-depth consideration of root physiology (e.g. uptake, exsudation), form (space-time dynamics of soil exploration) and ecology (including root environment), will settle the bases for designing root ideotypes for specific environments, for low-input agriculture or for successful agricultural production with minimal impact on the environment. This report summarizes root research initiated in our lab between 2000 and 2004 in the following areas: quantitative analysis of root branching in bananas, high throughput characterisation of root morphology, image analysis, QTL mapping of detailed features of root architecture in rice, and attempts to settle a Crop Root Research Consortium. (author)

  20. Investigations into rhizosphere microflora. IV. Fungal association in different root regions of some rainy-season crops

    Directory of Open Access Journals (Sweden)

    V. B. Srivastava

    2015-01-01

    Full Text Available Non-rhizosphere, rhizosphere and rhizoplane microflora of the crown and distal regions of Echinochloa crusgalli (L. Beauv. and Paspalum scrobiculatum L. were studied from seedling stage to the harvest. The variation in bacterial and fungal flora in relation to host species, stage of development and żonę of the rhizosphere were studied. The differences between fungal and bacterial flora are described. The relation between rhizosphere microflora and roots exudates is described.

  1. Fine-tuning by strigolactones of root response to low phosphate.

    Science.gov (United States)

    Kapulnik, Yoram; Koltai, Hinanit

    2016-03-01

    Strigolactones are plant hormones that regulate the development of different plant parts. In the shoot, they regulate axillary bud outgrowth and in the root, root architecture and root-hair length and density. Strigolactones are also involved with communication in the rhizosphere, including enhancement of hyphal branching of arbuscular mycorrhizal fungi. Here we present the role and activity of strigolactones under conditions of phosphate deprivation. Under these conditions, their levels of biosynthesis and exudation increase, leading to changes in shoot and root development. At least for the latter, these changes are likely to be associated with alterations in auxin transport and sensitivity. On the other hand, strigolactones may positively affect plant-mycorrhiza interactions and thereby promote phosphate acquisition by the plant. Strigolactones may be a way for plants to fine-tune their growth pattern under phosphate deprivation. © 2015 Institute of Botany, Chinese Academy of Sciences.

  2. Structure and dynamics of microbe-exuded polymers and their interactions with calcite surfaces.

    Energy Technology Data Exchange (ETDEWEB)

    Cygan, Randall Timothy; Mitchell, Ralph (Harvard University, Cambridge, MA); Perry, Thomas D. (Harvard University, Cambridge, MA)

    2005-12-01

    Cation binding by polysaccharides is observed in many environments and is important for predictive environmental modeling, and numerous industrial and food technology applications. The complexities of these organo-cation interactions are well suited to predictive molecular modeling studies for investigating the roles of conformation and configuration of polysaccharides on cation binding. In this study, alginic acid was chosen as a model polymer and representative disaccharide and polysaccharide subunits were modeled. The ability of disaccharide subunits to bind calcium and to associate with the surface of calcite was investigated. The findings were extended to modeling polymer interactions with calcium ions.

  3. Effects of arbuscular mycorrhizae on tomato yield, nutrient uptake, water relations, and soil carbon dynamics under deficit irrigation in field conditions.

    Science.gov (United States)

    Bowles, Timothy M; Barrios-Masias, Felipe H; Carlisle, Eli A; Cavagnaro, Timothy R; Jackson, Louise E

    2016-10-01

    Plant strategies to cope with future droughts may be enhanced by associations between roots and soil microorganisms, including arbuscular mycorrhizal (AM) fungi. But how AM fungi affect crop growth and yield, together with plant physiology and soil carbon (C) dynamics, under water stress in actual field conditions is not well understood. The well-characterized mycorrhizal tomato (Solanum lycopersicum L.) genotype 76R (referred to as MYC+) and the mutant nonmycorrhizal tomato genotype rmc were grown in an organic farm with a deficit irrigation regime and control regime that replaced evapotranspiration. AM increased marketable tomato yields by ~25% in both irrigation regimes but did not affect shoot biomass. In both irrigation regimes, MYC+ plants had higher plant nitrogen (N) and phosphorus (P) concentrations (e.g. 5 and 24% higher N and P concentrations in leaves at fruit set, respectively), 8% higher stomatal conductance (gs), 7% higher photosynthetic rates (Pn), and greater fruit set. Stem water potential and leaf relative water content were similar in both genotypes within each irrigation regime. Three-fold higher rates of root sap exudation in detopped MYC+ plants suggest greater capacity for water uptake through osmotic driven flow, especially in the deficit irrigation regime in which root sap exudation in rmc was nearly absent. Soil with MYC+ plants also had slightly higher soil extractable organic C and microbial biomass C at anthesis but no changes in soil CO2 emissions, although the latter were 23% lower under deficit irrigation. This study provides novel, field-based evidence for how indigenous AM fungi increase crop yield and crop water use efficiency during a season-long deficit irrigation and thus play an important role in coping with increasingly limited water availability in the future. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. ROOT Reference Documentation

    CERN Document Server

    Fuakye, Eric Gyabeng

    2017-01-01

    A ROOT Reference Documentation has been implemented to generate all the lists of libraries needed for each ROOT class. Doxygen has no option to generate or add the lists of libraries for each ROOT class. Therefore shell scripting and a basic C++ program was employed to import the lists of libraries needed by each ROOT class.

  5. Simulating root carbon storage with a coupled carbon — Water cycle root model

    Science.gov (United States)

    Kleidon, A.; Heimann, M.

    1996-12-01

    Is it possible to estimate carbon allocation to fine roots from the water demands of the vegetation? We assess this question by applying a root model which is based on optimisation principles. The model uses a new formulation of water uptake by fine roots, which is necessary to explicitly take into account the highly dynamic and non-steady process of water uptake. Its carbon dynamics are driven by maximising the water uptake while keeping maintenance costs at a minimum. We apply the model to a site in northern Germany and check averaged vertical fine root biomass distribution against measured data. The model reproduces the observed values fairly well and the approach seems promising. However, more validation is necessary, especially on the predicted dynamics of the root biomass.

  6. Spatially Resolved Carbon Isotope and Elemental Analyses of the Root-Rhizosphere-Soil System to Understand Below-ground Nutrient Interactions

    Science.gov (United States)

    Denis, E. H.; Ilhardt, P.; Tucker, A. E.; Huggett, N. L.; Rosnow, J. J.; Krogstad, E. J.; Moran, J.

    2017-12-01

    The intimate relationships between plant roots, rhizosphere, and soil are fostered by the release of organic compounds from the plant (through various forms of rhizodeposition) into soil and the simultaneous harvesting and delivery of inorganic nutrients from the soil to the plant. This project's main goal is to better understand the spatial controls on bi-directional nutrient exchange through the rhizosphere and how they impact overall plant health and productivity. Here, we present methods being developed to 1) spatially track the release and migration of plant-derived organics into the rhizosphere and soil and 2) map the local inorganic geochemical microenvironments within and surrounding the rhizosphere. Our studies focused on switchgrass microcosms containing soil from field plots at the Kellogg Biological Station (Hickory Corners, Michigan), which have been cropped with switchgrass for nearly a decade. We used a 13CO2 tracer to label our samples for both one and two diel cycles and tracked subsequent movement of labeled organic carbon using spatially specific δ13C analysis (with 50 µm resolution). The laser ablation-isotope ratio mass spectrometry (LA-IRMS) approach allowed us to map the extent of 13C-label migration into roots, rhizosphere, and surrounding soil. Preliminary results show the expected decrease of organic exudates with distance from a root and that finer roots (<0.1 mm) incorporated more 13C-label than thicker roots, which likely correlates to specific root growth rates. We are adapting both laser induced breakdown spectroscopy (LIBS) and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) to spatially map inorganic nutrient content in the exact same samples used for LA-IRMS analysis. Both of these methods provide rapid surface mapping of a wide range of elements (with high dynamic range) at 150 μm spatial resolution. Preliminary results show that, based on elemental content, we can distinguish between roots, rhizosphere

  7. Conjoined lumbosacral nerve roots

    International Nuclear Information System (INIS)

    Kyoshima, Kazumitsu; Nishiura, Iwao; Koyama, Tsunemaro

    1986-01-01

    Several kinds of the lumbosacral nerve root anomalies have already been recognized, and the conjoined nerve roots is the most common among them. It does not make symptoms by itself, but if there is a causation of neural entrapment, for example, disc herniation, lateral recessus stenosis, spondylolisthesis, etc., so called ''biradicular syndrome'' should occur. Anomalies of the lumbosacral nerve roots, if not properly recognized, may lead to injury of these nerves during operation of the lumbar spine. Recently, the chance of finding these anomalous roots has been increased more and more with the use of metrizamide myelography and metrizamide CT, because of the improvement of the opacification of nerve roots. We describe the findings of the anomalous roots as revealed by these two methods. They demonstrate two nerve roots running parallel and the asymmetrical wide root sleeve. Under such circumstances, it is important to distinguish the anomalous roots from the normal ventral and dorsal roots. (author)

  8. Looking deep inside: detection of low-abundance proteins in leaf extracts of Arabidopsis and phloem exudates of pumpkin.

    Science.gov (United States)

    Fröhlich, Andreas; Gaupels, Frank; Sarioglu, Hakan; Holzmeister, Christian; Spannagl, Manuel; Durner, Jörg; Lindermayr, Christian

    2012-07-01

    The field of proteomics suffers from the immense complexity of even small proteomes and the enormous dynamic range of protein concentrations within a given sample. Most protein samples contain a few major proteins, which hamper in-depth proteomic analysis. In the human field, combinatorial hexapeptide ligand libraries (CPLL; such as ProteoMiner) have been used for reduction of the dynamic range of protein concentrations; however, this technique is not established in plant research. In this work, we present the application of CPLL to Arabidopsis (Arabidopsis thaliana) leaf proteins. One- and two-dimensional gel electrophoresis showed a decrease in high-abundance proteins and an enrichment of less abundant proteins in CPLL-treated samples. After optimization of the CPLL protocol, mass spectrometric analyses of leaf extracts led to the identification of 1,192 proteins in control samples and an additional 512 proteins after the application of CPLL. Upon leaf infection with virulent Pseudomonas syringae DC3000, CPLL beads were also used for investigating the bacterial infectome. In total, 312 bacterial proteins could be identified in infected Arabidopsis leaves. Furthermore, phloem exudates of pumpkin (Cucurbita maxima) were analyzed. CPLL prefractionation caused depletion of the major phloem proteins 1 and 2 and improved phloem proteomics, because 67 of 320 identified proteins were detectable only after CPLL treatment. In sum, our results demonstrate that CPLL beads are a time- and cost-effective tool for reducing major proteins, which often interfere with downstream analyses. The concomitant enrichment of less abundant proteins may facilitate a deeper insight into the plant proteome.

  9. Root canal irrigants

    OpenAIRE

    Kandaswamy, Deivanayagam; Venkateshbabu, Nagendrababu

    2010-01-01

    Successful root canal therapy relies on the combination of proper instrumentation, irrigation, and obturation of the root canal. Of these three essential steps of root canal therapy, irrigation of the root canal is the most important determinant in the healing of the periapical tissues. The primary endodontic treatment goal must thus be to optimize root canal disinfection and to prevent reinfection. In this review of the literature, various irrigants and the interactions between irrigants are...

  10. A Bacillus subtilis Sensor Kinase Involved in Triggering Biofilm Formation on the Roots of Tomato Plants

    Science.gov (United States)

    Chen, Yun; Cao, Shugeng; Chai, Yunrong; Clardy, Jon; Kolter, Roberto; Guo, Jian-hua; Losick, Richard

    2012-01-01

    SUMMARY The soil bacterium Bacillus subtilis is widely used in agriculture as a biocontrol agent able to protect plants from a variety of pathogens. Protection is thought to involve the formation of bacterial communities - biofilms - on the roots of the plants. Here we used confocal microscopy to visualize biofilms on the surface of the roots of tomato seedlings and demonstrated that biofilm formation requires genes governing the production of the extracellular matrix that holds cells together. We further show that biofilm formation was dependent on the sensor histidine kinase KinD and in particular on an extracellular CACHE domain implicated in small molecule sensing. Finally, we report that exudates of tomato roots strongly stimulated biofilm formation ex planta and that an abundant small molecule in the exudates, l-malic acid, was able to stimulate biofilm formation at high concentrations in a manner that depended on the KinD CACHE domain. We propose that small signaling molecules released by the roots of tomato plants are directly or indirectly recognized by KinD, triggering biofilm formation. PMID:22716461

  11. GLO-Roots: an imaging platform enabling multidimensional characterization of soil-grown root systems

    Science.gov (United States)

    Rellán-Álvarez, Rubén; Lobet, Guillaume; Lindner, Heike; Pradier, Pierre-Luc; Sebastian, Jose; Yee, Muh-Ching; Geng, Yu; Trontin, Charlotte; LaRue, Therese; Schrager-Lavelle, Amanda; Haney, Cara H; Nieu, Rita; Maloof, Julin; Vogel, John P; Dinneny, José R

    2015-01-01

    Root systems develop different root types that individually sense cues from their local environment and integrate this information with systemic signals. This complex multi-dimensional amalgam of inputs enables continuous adjustment of root growth rates, direction, and metabolic activity that define a dynamic physical network. Current methods for analyzing root biology balance physiological relevance with imaging capability. To bridge this divide, we developed an integrated-imaging system called Growth and Luminescence Observatory for Roots (GLO-Roots) that uses luminescence-based reporters to enable studies of root architecture and gene expression patterns in soil-grown, light-shielded roots. We have developed image analysis algorithms that allow the spatial integration of soil properties, gene expression, and root system architecture traits. We propose GLO-Roots as a system that has great utility in presenting environmental stimuli to roots in ways that evoke natural adaptive responses and in providing tools for studying the multi-dimensional nature of such processes. DOI: http://dx.doi.org/10.7554/eLife.07597.001 PMID:26287479

  12. Genetic Determinism of Sensitivity to Corynespora cassiicola Exudates in Rubber Tree (Hevea brasiliensis).

    Science.gov (United States)

    Tran, Dinh Minh; Clément-Demange, André; Déon, Marine; Garcia, Dominique; Le Guen, Vincent; Clément-Vidal, Anne; Soumahoro, Mouman; Masson, Aurélien; Label, Philippe; Le, Mau Tuy; Pujade-Renaud, Valérie

    2016-01-01

    An indirect phenotyping method was developed in order to estimate the susceptibility of rubber tree clonal varieties to Corynespora Leaf Fall (CLF) disease caused by the ascomycete Corynespora cassiicola. This method consists in quantifying the impact of fungal exudates on detached leaves by measuring the induced electrolyte leakage (EL%). The tested exudates were either crude culture filtrates from diverse C. cassiicola isolates or the purified cassiicolin (Cas1), a small secreted effector protein produced by the aggressive isolate CCP. The test was found to be quantitative, with the EL% response proportional to toxin concentration. For eight clones tested with two aggressive isolates, the EL% response to the filtrates positively correlated to the response induced by conidial inoculation. The toxicity test applied to 18 clones using 13 toxinic treatments evidenced an important variability among clones and treatments, with a significant additional clone x treatment interaction effect. A genetic linkage map was built using 306 microsatellite markers, from the F1 population of the PB260 x RRIM600 family. Phenotyping of the population for sensitivity to the purified Cas1 effector and to culture filtrates from seven C. cassiicola isolates revealed a polygenic determinism, with six QTL detected on five chromosomes and percentages of explained phenotypic variance varying from 11 to 17%. Two common QTL were identified for the CCP filtrate and the purified cassiicolin, suggesting that Cas1 may be the main effector of CCP filtrate toxicity. The CCP filtrate clearly contrasted with all other filtrates. The toxicity test based on Electrolyte Leakage Measurement offers the opportunity to assess the sensitivity of rubber genotypes to C. cassiicola exudates or purified effectors for genetic investigations and early selection, without risk of spreading the fungus in plantations. However, the power of this test for predicting field susceptibility of rubber clones to CLF will have

  13. Can Wound Exudate from Venous Leg Ulcers Measure Wound Pain Status?: A Pilot Study.

    Directory of Open Access Journals (Sweden)

    Taichi Goto

    Full Text Available We investigated the associations between the self-evaluated pain status and two pain biomarker candidates, nerve growth factor and S100A8/A9, in exudate from venous leg ulcer to finally develop an objective pain evaluation method. Patients with venous leg ulcer participated in this cross-sectional observational study conducted between April and October 2014 at two medical facilities. During routine wound care, each participant self-evaluated their pain status at each examination using the 10-point numerical rating scale (present pain intensity and the short-form McGill Pain Questionnaire 2 (continuous pain, intermittent pain, neuropathic pain, affective descriptors, and total score. Venous leg ulcer exudate sample was collected after wound cleansing. The nerve growth factor and S100A8/A9 concentrations in the venous leg ulcer exudate were measured by enzyme-linked immunosorbent assay and standardized according to the wound area. The association between each pain status and the two standardized protein concentrations was evaluated using Spearman's correlation coefficient. In 30 sample collected from 13 participants, the standardized nerve growth factor concentration was negatively correlated with continuous pain (ρ = -0.47, P = 0.01, intermittent pain (ρ = -0.48, P = 0.01, neuropathic pain (ρ = -0.51, P = 0.01, and total score (ρ = -0.46, P = 0.01. The standardized S100A8/A9 concentration was positively correlated with present pain intensity (ρ = 0.46, P = 0.03 and continuous pain (ρ = 0.48, P = 0.03. Thus, these two proteins may be useful for objective evaluation of wound pain in venous leg ulcer patients.

  14. Oil exudation and histological structures of duck egg yolks during brining.

    Science.gov (United States)

    Lai, K M; Chung, W H; Jao, C L; Hsu, K C

    2010-04-01

    Changes in oil exudation and histological structures of salted duck egg yolks during brining up to 5 wk were investigated. During brining, the salt contents of albumen, exterior yolk (hardened portion), and interior yolk (soft or liquid portion) gradually increased accompanied by slight decreases in moisture content. The hardening ratio of salted egg yolks increased rapidly to about 60% during the first week of brining and then reached 100% at the end of brining. After brining, part of the lipids in salted egg yolk became free due to the structural changes of low-density lipoprotein induced by dehydration and increase of salt content, and more free lipids in salted egg yolk were released after the cooking process. With the brining time increased up to 5 wk, the outer region of the cooked salted yolk gradually changed into dark brown, brown, orange, and then dark brown, whereas the center region changed into light yellow, yellow, dark yellow, and then yellow again. The microstructures of cooked salted egg yolks showed that the yolk spheres in the outer and middle regions retained their original shape, with some shrinking and being packed more loosely when brining time increased, and the exuded oil filled the space between the spheres. Furthermore, the yolk spheres in the center region transformed to a round shape but still showed granulation after 4 wk of brining, whereas they were mostly disrupted after 2 to 5 wk of brining. One of the most important characteristics of cooked salted egg yolks, gritty texture, contributed to oil exudation and granulated yolk spheres were observed at the brining time of 4 wk.

  15. Gelation of Soy Milk with Hagfish Exudate Creates a Flocculated and Fibrous Emulsion- and Particle Gel.

    Directory of Open Access Journals (Sweden)

    Lukas Böni

    Full Text Available Hagfish slime is an ultra dilute, elastic and cohesive hydrogel that deploys within milliseconds in cold seawater from a glandularly secreted exudate. The slime is made of long keratin-like fibers and mucin-like glycoproteins that span a network which entraps water and acts as a defense mechanism against predators. Unlike other hydrogels, the slime only confines water physically and is very susceptible to mechanical stress, which makes it unsuitable for many processing operations and potential applications. Despite its huge potential, little work has been done to improve and functionalize the properties of this hydrogel. To address this shortcoming, hagfish exudate was mixed with a soy protein isolate suspension (4% w/v and with a soy emulsion (commercial soy milk to form a more stable structure and combine the functionalities of a suspension and emulsion with those of the hydrogel. Hagfish exudate interacted strongly with the soy systems, showing a markedly increased viscoelasticity and water retention. Hagfish mucin was found to induce a depletion and bridging mechanism, which caused the emulsion and suspension to flocculate, making "soy slime", a cohesive and cold-set emulsion- and particle gel. The flocculation network increases viscoelasticity and substantially contributes to liquid retention by entrapping liquid in the additional confinements between aggregated particles and protein fibers. Because the mucin-induced flocculation resembles the salt- or acid-induced flocculation in tofu curd production, the soy slime was cooked for comparison. The cooked soy slime was similar to conventional cooked tofu, but possessed a long-range cohesiveness from the fibers. The fibrous, cold-set, and curd-like structure of the soy slime represents a novel way for a cold coagulation and fiber incorporation into a suspension or emulsion. This mechanism could be used to efficiently gel functionalized emulsions or produce novel tofu-like structured food

  16. Gelation of Soy Milk with Hagfish Exudate Creates a Flocculated and Fibrous Emulsion- and Particle Gel

    Science.gov (United States)

    Böni, Lukas; Rühs, Patrick A.; Windhab, Erich J.; Fischer, Peter; Kuster, Simon

    2016-01-01

    Hagfish slime is an ultra dilute, elastic and cohesive hydrogel that deploys within milliseconds in cold seawater from a glandularly secreted exudate. The slime is made of long keratin-like fibers and mucin-like glycoproteins that span a network which entraps water and acts as a defense mechanism against predators. Unlike other hydrogels, the slime only confines water physically and is very susceptible to mechanical stress, which makes it unsuitable for many processing operations and potential applications. Despite its huge potential, little work has been done to improve and functionalize the properties of this hydrogel. To address this shortcoming, hagfish exudate was mixed with a soy protein isolate suspension (4% w/v) and with a soy emulsion (commercial soy milk) to form a more stable structure and combine the functionalities of a suspension and emulsion with those of the hydrogel. Hagfish exudate interacted strongly with the soy systems, showing a markedly increased viscoelasticity and water retention. Hagfish mucin was found to induce a depletion and bridging mechanism, which caused the emulsion and suspension to flocculate, making “soy slime”, a cohesive and cold-set emulsion- and particle gel. The flocculation network increases viscoelasticity and substantially contributes to liquid retention by entrapping liquid in the additional confinements between aggregated particles and protein fibers. Because the mucin-induced flocculation resembles the salt- or acid-induced flocculation in tofu curd production, the soy slime was cooked for comparison. The cooked soy slime was similar to conventional cooked tofu, but possessed a long-range cohesiveness from the fibers. The fibrous, cold-set, and curd-like structure of the soy slime represents a novel way for a cold coagulation and fiber incorporation into a suspension or emulsion. This mechanism could be used to efficiently gel functionalized emulsions or produce novel tofu-like structured food products. PMID

  17. Diffusion-weighted MR imaging of pleural fluid: differentiation of transudative vs exudative pleural effusions

    International Nuclear Information System (INIS)

    Baysal, T.; Bulut, T.; Dusak, A.; Dogan, M.; Goekirmak, M.; Kalkan, S.

    2004-01-01

    The aim of this study was to evaluate the ability of diffusion-weighted MRI in differentiating transudative from exudative pleural effusions. Fifty-seven patients with pleural effusion were studied. Diffusion-weighted imaging (DWI) was performed with an echo-planar imaging (EPI) sequence (b values 0, 1000 s/mm 2 ) in 52 patients. The apparent diffusion coefficient (ADC) values were reconstructed from three different regions. Subsequently, thoracentesis was performed and the pleural fluid was analyzed. Laboratory results revealed 20 transudative and 32 exudative effusions. Transudates had a mean ADC value of 3.42±0.76 x 10 -3 mm 2 /s. Exudates had a mean ADC value of 3.18±1.82 x 10 -3 mm 2 /s. The optimum cutoff point for ADC values was 3.38 x 10 -3 mm 2 /s with a sensitivity of 90.6% and specificity of 85%. A significant negative correlation was seen between ADC values and pleural fluid protein, albumin concentrations and lactate dehydrogenase (LDH) measurements (r=-0.69, -0.66, and -0.46, respectively; p<0.01). The positive predictive value, negative predictive value, and diagnostic accuracy of ADC values were determined to be 90.6, 85, and 88.5%, respectively. The application of diffusion gradients to analyze pleural fluid may be an alternative to the thoracentesis. Non-invasive characterization of a pleural effusion by means of DWI with single-shot EPI technique may obviate the need for thoracentesis with its associated patient morbidity. (orig.)

  18. Diagnostic yield and safety of closed needle pleural biopsy in exudative pleural effusion.

    Science.gov (United States)

    Rajawat, Govind Singh; Batra, Supreet; Takhar, Rajendra Prasad; Rathi, Lalit; Bhandari, Chand; Gupta, Manohar Lal

    2017-01-01

    Closed pleural biopsy was previously considered a procedure of choice in cases of undiagnosed pleural effusion with good efficacy. Currently, the closed pleural biopsy has been replaced by thoracoscopic biopsy but not easily available in resource-limited setups. The objective of this study was to analyze the diagnostic yield and safety of closed needle pleural biopsy in exudative pleural effusion and assessment of patients' characteristics with the yield of pleural biopsy. This was a cross-sectional study. This study was conducted at Institute of Respiratory Diseases, SMS Medical College, Jaipur, a tertiary care center of West India. A total of 250 cases of pleural effusion were evaluated with complete pleural fluid biochemical, microbiological, and cytological examination. Out of these 250 patients, 59 were excluded from the study as the diagnosis could be established on initial pleural fluid examination. The remaining (191) patients were considered for closed pleural biopsy with Abrams pleural biopsy needle. The main outcome measure was diagnostic yield in the form of confirming diagnosis. Out of the 191 patients with exudative lymphocytic pleural effusion, 123 (64.40%) were diagnosed on the first pleural biopsy. Among the remaining 68 patients, 22 patients had repeat pleural biopsy with a diagnostic yield of 59.9%. The overall pleural biopsy could establish the diagnosis in 136 (71.20%) patients with pleural effusion. The most common diagnosis on pleural biopsy was malignancy followed by tuberculosis. Closed pleural biopsy provides diagnostic yield nearly comparative to thoracoscopy in properly selected patients of pleural effusions. In view of good yield, low cost, easy availability, and very low complication rate, it should be used routinely in all cases of undiagnosed exudative lymphocytic pleural effusion. There was no comparison with a similar group undergoing thoracoscopic pleural biopsy.

  19. Risk factors for exudative age-related macular degeneration in a large French case-control study.

    Science.gov (United States)

    Zerbib, Jennyfer; Delcourt, Cécile; Puche, Nathalie; Querques, Giuseppe; Cohen, Salomon Yves; Sahel, José; Korobelnik, Jean-François; Le Goff, Mélanie; Souied, Eric H

    2014-06-01

    The purpose of the CAP (Creteil AMD PHRC-funded) Study was to analyze risk factors of exudative age-related macular degeneration (AMD) in a large French case-control population. One thousand and twenty-four patients with exudative AMD and 275 controls were recruited. Information about lifestyle, medical history, and dietary intake were collected. Associations of risk factors were estimated using logistic regression. After multivariate adjustment, CFH Y402H and ARMS2 A69S polymorphisms were associated with very high risk for exudative AMD (OR = 6.21 and OR = 11.7, respectively, p cooking oils rich in omega 3 fatty acids was significantly associated with a reduced risk of exudative AMD (OR = 0.55, 95 % CI: 0.36-0.84, p = 0.006), as well as a high consumption of fruits (OR = 0.60, 95 % CI: 0.37-0.98, p = 0.04), but not the consumption of fish, vegetables or oils rich in omega 6. High waist circumference was associated with increased risk for exudative AMD (OR = 2.53, p cooking oils harboring a beneficial omega-3 fatty acid profile.

  20. Status of Exudative Pleural Effusion in Adults of South Khorasan Province, Northeast Iran: Pleural Tuberculosis Tending toward Elderly

    Directory of Open Access Journals (Sweden)

    Sayyed Gholam Reza Mortazavi-Moghaddam

    2016-07-01

    Full Text Available The causes and situation of exudative pleural effusion vary from one area to another. A cross-sectional study was conducted on 327 patients with exudative pleural effusion in South Khorasan province (Iran. The patients were older than 12 years and comprised 172 (52.6% males and 155 (47.4% females. The study commenced in 2007 with seven years duration. The Light’s criteria were used to define exudative effusion. Procedures including pleural fluid analysis, microbiological study, pleural biopsy, and systemic investigations were conducted to determine the special cause of pleural effusion. The mean age of the patients was 63.4±18.4 years. Malignancies, tuberculosis, and parapneumonia pleural exudation were diagnosed in 125 (38.2%, 48 (14.7%, and 45 (13.8% cases, respectively. Among malignant effusions, metastasis from lung cancer made 48 (38.4% of the cases. The origin of metastasis was not determined in 44 (35.2% patients. The mean age of patients was not significantly different between malignant (66.9±14.3 years and tuberculosis (63.9±19.7 years cases (P=0.16. The older age of tuberculosis patients could be a new discussion point on the overall impression created on the subject of tuberculosis pleural exudation (TB-PLE occurring in young people.

  1. MICROBIAL IMPACTS ON THE MIGRATION OF ACTINIDES -EFFECTS OF EXUDATES ON ADSORPTION-

    International Nuclear Information System (INIS)

    OHNUKI, T.; OZAKI, T.; YOSHIDA, T.; NANKAWA, T.; KOZAI, N.; SAKAMOTO, F.; SUZUKI, Y.; FRANCIS, A.J.

    2006-01-01

    The interaction of actinides with microorganisms has been extensively studied to elucidate migration behavior of actinides in the environments. However, the mechanisms of interaction of microorganisms and actinides are poorly understood. They have been conducting basic science on microbial accumulation of actinides in order to elucidate the environmental behavior of actinides under relevant conditions. The effect of exudates from bacteria cells on the sorption of Eu(III) and Cm(III) by Chlorella vulgaris was studied by a batch method. The pH dependence of log K d of Eu(III) and Cm(III) for cellulose, major component of C. vulgaris cell, differed from that for C. vulgaris. On the contrary, log K d of Eu(III) and Cm(III) for cellulose in the solution containing exudates from C. vulgaris cells in a 0.5% NaCl solution showed a similar pH dependence to that by C. vulgaris. These results strongly suggested that exudates affect on the sorption of Eu(III) and Cm(III) on C. vulgaris. Effect of desferrioxamine B (DFO), one of exudates to chelate the insoluble Fe(III), on the sorption of Pu(IV), Th(IV) and Eu(III) by Pseudomonas fluorescens was studied. In the presence of DFO the sorption of Pu(IV), Th(IV) and Eu(III) on the cells increased with a decrease in pH from 7 to 4. In contrast, without DFO most of Pu(IV), Th(IV) and Eu(III) were precipitated from solution. Adsorption of DFO on the cells was negligible in the solution with and without metals. Adsorption of Pu(IV), Th(IV) and Eu(III) on P. fluorescens cells decreased in the order Eu(III) > Th(IV) > Pu(IV), which corresponds to increasing stability constant of the DFO complexes. These results indicate that Th(IV), Pu(IV) and Eu(III) dissociate when in contact with cells, after which the metals are adsorbed

  2. Microbial impacts on the migration of actinides. Effects of exudates on adsorption

    International Nuclear Information System (INIS)

    Ohnuki, Toshihiko; Ozaki, Takuo; Nakawa, Takuya; Kozai, Naofumi; Sakamoto, Fuminori; Suzuki, Yosinori; Yoshida, Takahiro; Francis, Arokiasamy J.

    2007-01-01

    The interaction of actinides with microorganisms has been extensively studied to elucidate migration behavior of actinides in the environments. However, the mechanisms of interaction of microorganisms and actinides are poorly understood. We have been conducting basic science on microbial accumulation of actinides in order to elucidate the environmental behavior of actinides under relevant conditions. The effect of exudates from bacteria cells on the sorption of Eu(III) and Cm(III) by Chlorella vulgaris was studied by a batch method. The pH dependence of log K d of Eu(III) and Cm(III) for cellulose, major component of C. vulgaris cell, differed from that for C. vulgaris. On the contrary, log K d of Eu(III) and Cm(III) for cellulose in the solution containing exudates from C. vulgaris cells in a 0.5% NaCl solution showed a similar pH dependence to that by C. vulgaris. These results strongly suggested that exudates affect on the sorption of Eu(III) and Cm(III) on C. vulgaris. Effect of desferrioxamine B (DFO), one of exudates to chelate with insoluble Fe(III), on the sorption of Pu(IV), Th(IV) and Eu(III) by Pseudomonas fluorescens was studied. In the presence of DFO the sorption of Pu(IV), Th(IV) and Eu(III) on the cells increased with a decrease in pH from 7 to 4. In contrast, without DFO most of Pu(IV), Th(IV) and Eu(III) were precipitated from solution. Adsorption of DFO on the cells was negligible in the solution with and without metals. Adsorption of Pu(IV), Th(IV) and Eu(III) on P. fluorescens cells decreased in the order Eu(III) > Th(IV) > Pu(IV), which corresponds to increasing stability constant of the DFO complexes. These results indicate that Th(IV), Pu(IV) and Eu(III) dissociate when in contact with cells, after which the metals are adsorbed. (author)

  3. Structure-antioxidant activity relationships of flavonoids isolated from the resinous exudate of Heliotropium sinuatum.

    Science.gov (United States)

    Modak, Brenda; Contreras, M Leonor; González-Nilo, Fernando; Torres, René

    2005-01-17

    Relationships between the structural characteristics of flavonoids isolated from the resinous exudate of Heliotropium sinuatum and their antioxidant activity were studied. Radical formation energies, DeltaH of dehydrogenation and spin densities were calculated using DFT methods (B3LYP/6-31G*). Results show that studied flavonoids can be divided into two sets according to their activity. It has been found that antioxidant activity depends both on substitution pattern of hydroxyl groups of the flavonoid skeleton and the presence of an unsaturation at the C2-C3 bond. A good tendency between DeltaH of dehydrogenation and antioxidant activity was established.

  4. A case of von Hippel-Lindau disease with exudative maculopathy

    Directory of Open Access Journals (Sweden)

    Basel T Ba′arah

    2009-01-01

    Full Text Available Von Hippel-Lindau (VHL disease is a rare multisystem familial tumor syndrome of autosomal dominant inheritance. Hallmark lesions include retinal, cerebellum and spinal cord hemangioblastomas, renal cell carcinomas, adrenal pheochromocytomas, angiomatous or cystic lesions of the kidneys, pancreas, and epididymis. We report a case of VHL disease in a 26-year-old patient who presented with exudative macular edema. Ocular and systemic studies revealed the presence of retinal and central nervous system hemangioblastomas, adrenal pheochromocytoma, multiple pancreatic, and kidney cysts. The retinal angiomas were successfully treated with argon laser photocoagulation and cryotherapy.

  5. High-Density Lipoprotein Function in Exudative Age-Related Macular Degeneration.

    Directory of Open Access Journals (Sweden)

    Laura Pertl

    Full Text Available High-density lipoproteins (HDL have long been implicated in the pathogenesis of age-related macular degeneration (AMD. However, conflicting results have been reported with regard to the associations of AMD with HDL-cholesterol levels. The present study is the first to assess HDL composition and metrics of HDL function in patients with exudative AMD and control patients.Blood samples were collected from 29 patients with exudative AMD and 26 age-matched control patients. Major HDL associated apolipoproteins were determined in apoB-depleted serum by immunoturbidimetry or ELISA, HDL-associated lipids were quantified enzymatically. To get an integrated measure of HDL quantity and quality, we assessed several metrics of HDL function, including cholesterol efflux capacity, anti-oxidative and anti-inflammatory activities using apoB-depleted serum from study participants.In our study, we observed that the HDL associated acute phase protein serum amyloid A (SAA was significantly increased in AMD patients (p<0.01, whereas all other assessed apolipoproteins including ApoA-I, apoA-II, apoC-II, apoC-III and apoE as well as major HDL associated lipids were not altered. HDL efflux capacity, anti-oxidative capacity and arylesterase activity were not different in AMD patients when compared with the control group. The ability of apoB-depleted serum to inhibit monocyte NF-κB expression was significantly improved in AMD patients (mean difference (MD -5.6, p<0.01. Moreover, lipoprotein-associated phospholipase A2 activity, a marker of vascular inflammation, was decreased in AMD subjects (MD -24.1, p<0.01.The investigated metrics of HDL composition and HDL function were not associated with exudative AMD in this study, despite an increased content of HDL associated SAA in AMD patients. Unexpectedly, anti-inflammatory activity of apoB-depleted serum was even increased in our study. Our data suggest that the investigated parameters of serum HDL function showed no

  6. The Wnt signaling pathway in familial exudative vitreoretinopathy and Norrie disease.

    Science.gov (United States)

    Warden, Scott M; Andreoli, Christopher M; Mukai, Shizuo

    2007-01-01

    The Wnt signaling pathway is highly conserved among species and has an important role in many cell biological processes throughout the body. This signaling cascade is involved in regulating ocular growth and development, and recent findings indicate that this is particularly true in the retina. Mutations involving different aspects of the Wnt signaling pathway are being linked to several diseases of retinal development. The aim of this article is to first review the Wnt signaling pathway. We will then describe two conditions, familial exudative vitreoretinopathy (FEVR) and Norrie disease (ND), which have been shown to be caused in part by defects in the Wnt signaling cascade.

  7. Plant-Microbe Communication Enhances Auxin Biosynthesis by a Root-Associated Bacterium, Bacillus amyloliquefaciens SQR9.

    Science.gov (United States)

    Liu, Yunpeng; Chen, Lin; Zhang, Nan; Li, Zunfeng; Zhang, Guishan; Xu, Yu; Shen, Qirong; Zhang, Ruifu

    2016-04-01

    Mechanisms by which beneficial rhizobacteria promote plant growth include tryptophan-dependent indole-3-acetic acid (IAA) synthesis. The abundance of tryptophan in the rhizosphere, however, may influence the level of benefit provided by IAA-producing rhizobacteria. This study examined the cucumber-Bacillus amyloliquefaciens SQR9 system and found that SQR9, a bacterium previously shown to enhance the growth of cucumber, increased root secretion of tryptophan by three- to fourfold. Using a split-root system, SQR9 colonization of roots in one chamber not only increased tryptophan secretion from the noninoculated roots but also increased the expression of the cucumber tryptophan transport gene but not the anthranilate synthesis gene in those roots. The increased tryptophan in isolated rhizosphere exudates was sufficient to support increased IAA production by SQR9. Moreover, SQR9 colonization of roots in one chamber in the split-root system resulted in sufficient tryptophan production by the other roots to upregulate SQR9 IAA biosynthesis genes, including a 27-fold increase in the indole-3-acetonitrilase gene yhcX during subsequent colonization of those roots. Deletion of yhcX eliminated SQR9-mediated increases in root surface area, likely by reducing IAA-stimulated lateral root growth. This study demonstrates a chemical dialogue between B. amyloliquefaciens and cucumber in which this communication contributes to bacteria-mediated plant-growth enhancement.

  8. Molecular Physiology of Root System Architecture in Model Grasses

    Science.gov (United States)

    Hixson, K.; Ahkami, A. H.; Anderton, C.; Veličković, D.; Myers, G. L.; Chrisler, W.; Lindenmaier, R.; Fang, Y.; Yabusaki, S.; Rosnow, J. J.; Farris, Y.; Khan, N. E.; Bernstein, H. C.; Jansson, C.

    2017-12-01

    ) and leaf node axile root (LNR) during developmental stages of root formation. The root exudates also will be quantified and preliminary data will be used to engineer our microbial consortium to improve plant growth.

  9. Quantitative Simulation of Damage Roots on Inoculated Alfalfa by Arbuscular Mycorrhiza Fungi

    Directory of Open Access Journals (Sweden)

    Ying Liu

    2017-12-01

    Full Text Available Underground mining would cause ground subsidence damage and large amounts of cracks, which would result a loss of surface moisture and nutrient and intensifying drought. There are a few reports about damage to plant roots caused by coal mining. The irregular distribution of plant roots in soil and the different forces generated in process of surface subsidence are difficult to study comprehensively. The technologies to repair damaged plant roots have not been completely perfected yet. Based on quantitative simulation of alfalfa root cut-repair experiment, this paper discusses the influences of inoculated Arbuscular Mycorrhiza Fungi on alfalfa root and the mitigation effects of an inoculation on the growth of alfalfa. Root injured alfalfa were investigated by soil pot experiments. The result indicated that at the same cut degree, the growth situation of inoculated alfalfa is better than the contrast. Compared with the Olsen-P content, at cut level of 0 and 1/3, the sand of inoculated alfalfa has less Olsen-P than contrast, at cut degree of 1/2 and 2/3, the sand of inoculated alfalfa has more Olsen-P than contrast, at degree of 3/4, the sand of inoculated alfalfa has less Olsen-P than contrast, the change trend of Olsen-P content is concerned with the relative strength size of absorb Olsen-P by alfalfa root and dissolve Olsen-P by root exudates and hyphae interstate.

  10. In situ stimulation vs. bioaugmentation: Can microbial inoculation of plant roots enhance biodegradation of organic compounds?

    Energy Technology Data Exchange (ETDEWEB)

    Kingsley, M.T.; Metting, F.B. Jr.; Fredrickson, J.K. [Pacific Northwest Lab., Richland, WA (United States); Seidler, R.J. [Environmental Protection Agency, Corvallis, OR (United States). Environmental Research Lab.

    1993-06-01

    The use of plant roots and their associated rhizosphere bacteria for biocontainment and biorestoration offers several advantages for treating soil-dispersed contaminants and for application to large land areas. Plant roots function as effective delivery systems, since root growth transports bacteria vertically and laterally along the root in the soil column (see [ 1,2]). Movement of microbes along roots and downward in the soil column can be enhanced via irrigation [1-4]. For example, Ciafardini et al. [3] increased the nodulation and the final yield of soybeans during pod filling by including Bradyrhizobium japonicum in the irrigation water. Using rhizosphere microorganisms is advantageous for biodegradation of compounds that are degraded mainly by cometabolic processes, e.g., trichloroethylene (TCE). The energy source for bacterial growth and metabolism is supplied by the plant in the form of root exudates and other sloughed organic material. Plants are inexpensive, and by careful choice of species that possess either tap or fibrous root growth patterns, they can be used to influence mass transport of soil contaminants to the root surface via the transpiration stream [5]. Cropping of plants to remove heavy metals from contaminated soils has been proposed as a viable, low-cost, low-input treatment option [6]. The interest in use of plants as a remediation strategy has even reached the popular press [7], where the use of ragweed for the reclamation of sites contaminated with tetraethyl lead and other heavy metals was discussed.

  11. Pharmacokinetics of cephem antibiotics in exudate of pelvic retroperitoneal space after radical hysterectomy and pelvic lymphadenectomy.

    Science.gov (United States)

    Ito, K; Hayasaki, M; Tamaya, T

    1990-01-01

    Many cephalosporin antibiotics have recently been invented and attempts have been made to use them clinically. The choice of which of these drugs should be used has been difficult in gynecology. The efficacies of these drugs depend on their antibacterial spectra, potencies, and concentrations in tissues. This study was designed to investigate the pharmacokinetics of various cephem antibiotics in the exudate of the retroperitoneal space that is formed after radical hysterectomy and pelvic lymphadenectomy. These cephem antibiotics were cefoxitin, cefotiam, cefotetan, cefpiramide, cefminox, cefotaxime, ceftizoxime, cefoperazone, cefmenoxime, cefbuperazone, ceftazidime, cefpimizole, flomoxef, and cefuzonam. The maximum concentrations after administration of a 1-g dose in the exudate of the pelvic retroperitoneal space were 37.9 micrograms/ml with cefminox, 30.3 micrograms/ml with cefpimizole, 21.6 micrograms/ml with flomoxef, 21.5 micrograms/ml with ceftazidime, and 17.6 micrograms/ml with cefbuperazone, which were relatively high. When selecting antibiotics for prophylactic use against infections in the retroperitoneal space after radical hysterectomy and pelvic lymphadenectomy, on the basis of drug transfer, flomoxef, cefminox, cefbuperazone, ceftazidime, and cefpimizole were considered to be the drugs of first choice at a dose of 1 g. PMID:2393276

  12. In vitro antibacterial effect of tobacco leaf exudates against two bacterial plant pathogens

    Directory of Open Access Journals (Sweden)

    Yanelis Karina Capdesuñer

    2015-01-01

    Full Text Available Natural products are an alternative to control microorganisms that cause diseases in crops. This work aimed to evaluate different solvents for obtaining crude extracts from tobacco leaf exudates and to determine in vitro effect of these extracts against two phytopathogenic bacteria: Xanthomonas campestris(Xc and Pectobacterium carotovorum(Pc. Crude extracts from ten tobacco lines using solvents with polarities between 3.1 and 6.2 (dichloromethane, n-butanol, ethyl acetate, methanol and ethanol 90% were obtained. Ethanol 90% was selected as the best solvent for obtaining extracts from tobacco leaf exudates and as a substitute of dichloromethane due to the best yield. The chemical composition diversity of the ethanolic extracts was revealed by thin-layer chromatography. The antibacterial activity was evaluated by agar disk diffusion method recording the inhibition zones. Growth inhibition was observed for all extracts against Xc, and the better activity corresponded to the lines Nic 1061"TI 1738" and Nic 1016 "Incekara" until a minimal amount of 5 µg/ disc, with higher yield in case of the line Nic1061 . Only the extract of the line Nic 1015 was able to inhibit the growth of Pc until a minimal inhibitory concentration of 5 µg/disc. These results suggest a potential use of crude extracts from lines Nic 1061 and Nic 1015 "TI 1341" as an effective agent for the crop protection against Xc and Pc respectively.

  13. Recent advances in Rosaceae gum exudates: From synthesis to food and non-food applications.

    Science.gov (United States)

    Bouaziz, Fatma; Koubaa, Mohamed; Ellouz Ghorbel, Raoudha; Ellouz Chaabouni, Semia

    2016-05-01

    In recent years, great interest has been devoted to the development of new applications for natural gums. These molecules were used for a variety of purposes since they are chemically inert, non-toxic, less expensive, biodegradable and widely available. They represent one of the most abundant raw materials used not only in commercial food products, but also in cosmetic and pharmaceutical products. Plant gums take their advantages compared to other gums (e.g., from animal and microbial sources) mainly because of their acceptance by consumers. Despite of the well description given in literature for the features of plant gum exudates, there is a lack distinguishing the different families that are producing gums, and their potential applications. Among these gums, the ones produced by Rosaceae family (e.g., almond, apricot, cherry, peach, and plum plants) have been taking special attention. Thus, the aim of this review is to report the recent advances in Rosaceae gum exudates. An emphasis is given for the formation mechanisms of these gums, their chemical composition, functional properties and structures, beneficial properties, as well as their food/non-food applications. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. [Computed tomography of the temporal bone in diagnosis of chronic exudative otitis media].

    Science.gov (United States)

    Zelikovich, E I

    2005-01-01

    Computed tomography (CT) of the temporal bone was made in 37 patients aged 2 to 55 years with chronic exudative otitis media (CEOM). In 21 of them the pathology was bilateral. The analysis of 58 CT images has identified CT signs of chronic exudative otitis media. They include partial (17 temporary bones) or complete (38 temporal bones) block of the bone opening of the auditory tube, pneumatic defects of the tympanic cavity (58 temporal bones), pneumatic defects of the mastoid process and antrum (47 temporal bones), pathologic retraction of the tympanic membrane. The examination of the temporal bone detected both CT-signs of CEOM and other causes of hearing disorders in 14 patients (26 temporal bones) with CEOM symptoms and inadequately high hypoacusis. Among these causes were malformation of the auditory ossicula (n=5), malformation of the labynthine window (n=2), malformation of the middle and internal ear (n=4), a wide aqueduct of the vestibule, labyrinthine anomaly of Mondini's type (n=1), cochlear hypoplasia (n=4), stenosis of the internal acoustic meatuses (n=2). Sclerotic fibrous dysplasia was suggested in 2 temporal bones (by CT data). CT was repeated after surgical treatment of 10 patients (14 temporal bones) and visual assessment of tympanostomy results was made.

  15. Fundus Image Features Extraction for Exudate Mining in Coordination with Content Based Image Retrieval: A Study

    Science.gov (United States)

    Gururaj, C.; Jayadevappa, D.; Tunga, Satish

    2018-06-01

    Medical field has seen a phenomenal improvement over the previous years. The invention of computers with appropriate increase in the processing and internet speed has changed the face of the medical technology. However there is still scope for improvement of the technologies in use today. One of the many such technologies of medical aid is the detection of afflictions of the eye. Although a repertoire of research has been accomplished in this field, most of them fail to address how to take the detection forward to a stage where it will be beneficial to the society at large. An automated system that can predict the current medical condition of a patient after taking the fundus image of his eye is yet to see the light of the day. Such a system is explored in this paper by summarizing a number of techniques for fundus image features extraction, predominantly hard exudate mining, coupled with Content Based Image Retrieval to develop an automation tool. The knowledge of the same would bring about worthy changes in the domain of exudates extraction of the eye. This is essential in cases where the patients may not have access to the best of technologies. This paper attempts at a comprehensive summary of the techniques for Content Based Image Retrieval (CBIR) or fundus features image extraction, and few choice methods of both, and an exploration which aims to find ways to combine these two attractive features, and combine them so that it is beneficial to all.

  16. Use of a new silver barrier dressing, ALLEVYN Ag in exuding chronic wounds.

    LENUS (Irish Health Repository)

    Kotz, Paula

    2009-06-01

    Recognising and managing wounds at risk of infection is vital in wound management. ALLEVYN Ag dressings have been designed to manage exudate in chronic wounds that are at risk of infection; are displaying signs of local infection; or where a suspected increase in bacterial colonisation is delaying healing. They combine an absorbent silver sulfadiazine containing hydrocellular foam layer, with a perforated wound contact layer and highly breathable top film. The results presented are from a multi-centre clinical evaluation of 126 patients conducted to assess the performance of ALLEVYN Ag (Adhesive, Non Adhesive and Sacrum dressings) in a range of indications. Clinicians rated the dressings as acceptable for use in various wound types in 88% of patients. The majority of clinical signs of infection reduced between the initial and the final assessment. The condition of wound tissue and surrounding skin was observed to improve, and there was significant evidence of a reduction in the level of exudate from initial to final assessment (p < 0.001). Clinicians rated ALLEVYN Ag as satisfying or exceeding expectations in over 90% of patients. The evaluation showed the dressings to offer real benefits to patients and clinicians across multiple indications when used in conjunction with local protocols.

  17. Linkage and candidate gene analysis of X-linked familial exudative vitreoretinopathy.

    Science.gov (United States)

    Shastry, B S; Hejtmancik, J F; Plager, D A; Hartzer, M K; Trese, M T

    1995-05-20

    Familial exudative vitreoretinopathy (FEVR) is a hereditary eye disorder characterized by avascularity of the peripheral retina, retinal exudates, tractional detachment, and retinal folds. The disorder is most commonly transmitted as an autosomal dominant trait, but X-linked transmission also occurs. To initiate the process of identifying the gene responsible for the X-linked disorder, linkage analysis has been performed with three previously unreported three- or four-generation families. Two-point analysis showed linkage to MAOA (Zmax = 2.1, theta max = 0) and DXS228 (Zmax = 0.5, theta max = 0.11), and this was further confirmed by multipoint analysis with these same markers (Zmax = 2.81 at MAOA), which both lie near the gene causing Norrie disease. Molecular genetic analysis further reveals a missense mutation (R121W) in the third exon of the Norrie's disease gene that perfectly cosegregates with the disease through three generations in one family. This mutation was not detected in the unaffected family members and six normal unrelated controls, suggesting that it is likely to be the pathogenic mutation. Additionally, a polymorphic missense mutation (H127R) was detected in a severely affected patient.

  18. Flavonoids from Heliotropium subulatum exudate and their evaluation for antioxidant, antineoplastic and cytotoxic activities II.

    Science.gov (United States)

    Singh, Bharat; Sahu, Pooran M; Sharma, Ram A

    2017-02-01

    The flavonoids are the largest group of phenolic compounds isolated from a wide range of higher plants. These compounds work as antimicrobials, anti-insect agents and protect plants from other types of biotic and abiotic stresses. Various researchers have suggested that flavonoids possessed antioxidant, antineoplastic and cytotoxic activities. The main objective of this study was to test dichloromethane fraction of resinous exudate of Heliotropium subulatum for their antioxidant, antineoplastic and cytotoxic activities, as well as to search new antioxidant and antineoplastic agents for pharmaceutical formulations. Five flavonoids were isolated from resinous exudate of this plant species and screened for their in vitro and in vivo antioxidant models (DPPH radical scavenging, reducing power, superoxide anion scavenging, metal chelating scavenging systems, catalase and lipid peroxidation), antineoplastic (Sarcoma 180), and cytotoxic (Chinese hamster V79 cells) activities. Tricetin demonstrated maximum antioxidant activity against both in vitro and in vivo experimental systems while galangin exhibited maximum inhibition (78.35%) at a dose of 10 µg/kg/day against Sarcoma 180. Similarly, it was found that galangin also showed highest activity (21.1 ± 0.15%) at a concentration of 70 µg/ml to Chinese hamster V79 cells. The observed results suggest that tricetin has a potential to scavenge free radicals in both in vitro and in vivo models while the galangin could be considered as antitumor and cytotoxic agent.

  19. Exudate-based diabetic macular edema detection in fundus images using publicly available datasets

    Energy Technology Data Exchange (ETDEWEB)

    Giancardo, Luca [ORNL; Meriaudeau, Fabrice [ORNL; Karnowski, Thomas Paul [ORNL; Li, Yaquin [University of Tennessee, Knoxville (UTK); Garg, Seema [University of North Carolina; Tobin Jr, Kenneth William [ORNL; Chaum, Edward [University of Tennessee, Knoxville (UTK)

    2011-01-01

    Diabetic macular edema (DME) is a common vision threatening complication of diabetic retinopathy. In a large scale screening environment DME can be assessed by detecting exudates (a type of bright lesions) in fundus images. In this work, we introduce a new methodology for diagnosis of DME using a novel set of features based on colour, wavelet decomposition and automatic lesion segmentation. These features are employed to train a classifier able to automatically diagnose DME through the presence of exudation. We present a new publicly available dataset with ground-truth data containing 169 patients from various ethnic groups and levels of DME. This and other two publicly available datasets are employed to evaluate our algorithm. We are able to achieve diagnosis performance comparable to retina experts on the MESSIDOR (an independently labelled dataset with 1200 images) with cross-dataset testing (e.g., the classifier was trained on an independent dataset and tested on MESSIDOR). Our algorithm obtained an AUC between 0.88 and 0.94 depending on the dataset/features used. Additionally, it does not need ground truth at lesion level to reject false positives and is computationally efficient, as it generates a diagnosis on an average of 4.4 s (9.3 s, considering the optic nerve localization) per image on an 2.6 GHz platform with an unoptimized Matlab implementation.

  20. AM fungal exudates activate MAP kinases in plant cells in dependence from cytosolic Ca(2+) increase.

    Science.gov (United States)

    Francia, Doriana; Chiltz, Annick; Lo Schiavo, Fiorella; Pugin, Alain; Bonfante, Paola; Cardinale, Francesca

    2011-09-01

    The molecular dialogue occurring prior to direct contact between the fungal and plant partners of arbuscular-mycorrhizal (AM) symbioses begins with the release of fungal elicitors, so far only partially identified chemically, which can activate specific signaling pathways in the host plant. We show here that the activation of MAPK is also induced by exudates of germinating spores of Gigaspora margarita in cultured cells of the non-leguminous species tobacco (Nicotiana tabacum), as well as in those of the model legume Lotus japonicus. MAPK activity peaked about 15 min after the exposure of the host cells to the fungal exudates (FE). FE were also responsible for a rapid and transient increase in free cytosolic Ca(2+) in Nicotiana plumbaginifolia and tobacco cells, and pre-treatment with a Ca(2+)-channel blocker (La(3+)) showed that in these cells, MAPK activation was dependent on the cytosolic Ca(2+) increase. A partial dependence of MAPK activity on the common Sym pathway could be demonstrated for a cell line of L. japonicus defective for LjSym4 and hence unable to establish an AM symbiosis. Our results show that MAPK activation is triggered by an FE-induced cytosolic Ca(2+) transient, and that a Sym genetic determinant acts to modulate the intensity and duration of this activity. Copyright © 2011 Elsevier Masson SAS. All rights reserved.

  1. Antiprotozoal and Antiglycation Activities of Sesquiterpene Coumarins from Ferula narthex Exudate

    Directory of Open Access Journals (Sweden)

    Adnan Amin

    2016-09-01

    Full Text Available The exudate of Ferula narthex Boiss. (Apiaceae is widely used in the Indian subcontinent as a spice and because of its health effects. Six sesquiterpene coumarins have been isolated from this exudate: feselol, ligupersin A, asacoumarin A, 8′-O-acetyl-asacoumarin A, 10′R-karatavacinol and 10′R-acetyl-karatavacinol. Based on its use in infectious and diabetic conditions, the isolated constituents were evaluated for antimicrobial and antiglycation activities. Some compounds showed activity against protozoal parasites, asacoumarin A being the most active one against Plasmodium falciparum K1 (IC50 1.3 μM. With regard to antiglycation activity, in the BSA-glucose test, ligupersin A displayed the highest activity (IC50 0.41 mM, being more active than the positive control aminiguanidine (IC50 1.75 mM. In the BSA-MGO assay, the highest activity was shown by 8′-O-acetyl-asacoumarin A (IC50 1.03 mM, being less active than aminoguanidine (IC50 0.15 mM. Hence, the antiglycation activity of the isolated constituents was due to both oxidative and non-oxidative modes of inhibition.

  2. Fundus Image Features Extraction for Exudate Mining in Coordination with Content Based Image Retrieval: A Study

    Science.gov (United States)

    Gururaj, C.; Jayadevappa, D.; Tunga, Satish

    2018-02-01

    Medical field has seen a phenomenal improvement over the previous years. The invention of computers with appropriate increase in the processing and internet speed has changed the face of the medical technology. However there is still scope for improvement of the technologies in use today. One of the many such technologies of medical aid is the detection of afflictions of the eye. Although a repertoire of research has been accomplished in this field, most of them fail to address how to take the detection forward to a stage where it will be beneficial to the society at large. An automated system that can predict the current medical condition of a patient after taking the fundus image of his eye is yet to see the light of the day. Such a system is explored in this paper by summarizing a number of techniques for fundus image features extraction, predominantly hard exudate mining, coupled with Content Based Image Retrieval to develop an automation tool. The knowledge of the same would bring about worthy changes in the domain of exudates extraction of the eye. This is essential in cases where the patients may not have access to the best of technologies. This paper attempts at a comprehensive summary of the techniques for Content Based Image Retrieval (CBIR) or fundus features image extraction, and few choice methods of both, and an exploration which aims to find ways to combine these two attractive features, and combine them so that it is beneficial to all.

  3. Clinical performance of a new silver dressing, Contreet Foam, for chronic exuding venous leg ulcers

    DEFF Research Database (Denmark)

    Karlsmark, T; Agerslev, R H; Bendz, S H

    2003-01-01

    OBJECTIVE: This study aimed to evaluate the safety and performance of a new sustained silver-releasing dressing, Contreet Foam (Coloplast A/S), in the treatment of moderately to highly exuding chronic venous leg ulcers in which healing is delayed due to the presence of bacteria. METHOD: The clini......OBJECTIVE: This study aimed to evaluate the safety and performance of a new sustained silver-releasing dressing, Contreet Foam (Coloplast A/S), in the treatment of moderately to highly exuding chronic venous leg ulcers in which healing is delayed due to the presence of bacteria. METHOD......'s effect on the peri-ulcer area. Blood samples were analysed for silver content. RESULTS: Twenty-three out of 25 patients completed the study. One ulcer healed and no wound infections occurred during the study period. A mean 56% reduction in ulcer area (from 15.6 to 6.9 cm2) was recorded during the four...... weeks, and there was a mean 25% reduction in granulation tissue from dull to healthy after one week. Wound odour reduced significantly after one week. Mean dressing wear time was 3.1 days, and there were only minimal incidences of leakage. Serum silver levels did not exceed reference values. CONCLUSION...

  4. Monosaccharide composition of acidic gum exudates from Indian Acacia tortilis ssp. raddiana (Savi) Brenan.

    Science.gov (United States)

    Lakhera, Ajeet Kumar; Kumar, Vineet

    2017-01-01

    Acacia tortilis ssp. raddiana (Savi) Brenan commonly known as Israeli Babool has contributed immensely for sand dunes management in Indian desert leading to wind erosion control and increased biological productivity. The species is extensively used in traditional medicine system for a number of therapeutic applications and as nutraceutical. The polysaccharide was isolated in 43.6% yield from gum exudates. The monosaccharides, L-arabinose, D-galactose D-glucose, L-rhamnose and D-mannose were determined in molar ratio of 78.1%, 18.64%, 0.60%, 1.71% and 0.74% respectively. The molar ratio of uronic acids was studied using diverse spectrophotometric methods and compared with GLC. The content of D-galacturonic acid and D-glucuronic was determined as 3.88% and 4.35% respectively by GLC. The results were compared with the spectrophotometric methods. The results using DMP as chromogenic reagent are closer to that obtained by GLC. Structural analysis of the polysaccharide may provide scientific basis for nutraceutical, pharmaceutical and biological applications of gum exudates from A. tortilis, which is extensively planted in India. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. CLINICAL AND ELECTROPHYSIOLOGICAL EVALUATION AFTER INTRAVITREAL ZIV-AFLIBERCEPT FOR EXUDATIVE AGE-RELATED MACULAR DEGENERATION.

    Science.gov (United States)

    de Oliveira Dias, João Rafael; de Andrade, Gabriel Costa; Kniggendorf, Vinicius Ferreira; Novais, Eduardo Amorim; Maia, André; Meyer, Carsten; Watanabe, Sung Eun Song; Farah, Michel Eid; Rodrigues, Eduardo Büchele

    2017-08-01

    To evaluate the 6-month safety and efficacy of ziv-aflibercept intravitreal injections for treating exudative age-related macular degeneration. Fifteen patients with unilateral exudative age-related macular degeneration were enrolled. The best-corrected visual acuity was measured and spectral domain optical coherence tomography was performed at baseline and monthly. Full-field electroretinography and multifocal electroretinography were obtained at baseline and 4, 13, and 26 weeks after the first injection. All patients received three monthly intravitreal injections of ziv-aflibercept (1.25 mg) followed by as-needed treatment. Between baseline and 26 weeks, the mean logMAR best-corrected visual acuity improved (P = 0.00408) from 0.93 ± 0.4 (20/200) to 0.82 ± 0.5 (20/160) logarithm of the minimum angle of resolution, respectively; the central retinal thickness decreased significantly (P = 0.0007) from 490.3 ± 155.1 microns to 327.9 ± 101.5 microns; the mean total macular volume decreased significantly (P macular responses within the first central 15° showed significantly (P macular volume from baseline to 26 weeks. No retinal toxicity on full-field electroretinography or adverse events occurred during the follow-up period.

  6. MACULAR CHOROIDAL VOLUME CHANGES AFTER INTRAVITREAL BEVACIZUMAB FOR EXUDATIVE AGE-RELATED MACULAR DEGENERATION.

    Science.gov (United States)

    Palkovits, Stefan; Seidel, Gerald; Pertl, Laura; Malle, Eva M; Hausberger, Silke; Makk, Johanna; Singer, Christoph; Osterholt, Julia; Herzog, Sereina A; Haas, Anton; Weger, Martin

    2017-12-01

    To evaluate the effect of intravitreal bevacizumab on the macular choroidal volume and the subfoveal choroidal thickness in treatment naïve eyes with exudative age-related macular degeneration. The macular choroidal volume and the subfoveal choroidal thickness were measured using enhanced depth imaging optical coherence tomography. After a screening examination, each patient received 3 monthly intravitreal injections of 1.25 mg bevacizumab. One month after the third injection was a final assessment. Forty-seven patients with a mean age of 80 ± 6.4 years were included. The macular choroidal volume decreased significantly from median 4.1 mm (interquartile range 3.4-5.9) to median 3.9 mm (interquartile range 3.1-5.6) between the baseline and final examination (difference -0.46 mm, 95% confidence interval: -0.57 to 0.35, P macular choroidal volume at baseline and subfoveal choroidal thickness at baseline were not associated with the response to treatment. The macular choroidal volume and the subfoveal choroidal thickness decreased significantly after 3 monthly bevacizumab injections for exudative age-related macular degeneration.

  7. Vascular Endothelial Growth Factor Concentration in Chronic Subdural Hematoma Fluid Is Related to Computed Tomography Appearance and Exudation Rate

    Science.gov (United States)

    Weigel, Ralf; Hohenstein, Axel

    2014-01-01

    Abstract Chronic subdural hematoma (CSH) is characterized by a net increase of volume over time. Major underlying mechanisms appear to be hemorrhagic episodes and a continuous exudation, which may be studied using labeled proteins to yield an exudation rate in a given patient. We tested the hypothesis that the concentration of vascular endothelial growth factor (VEGF) in hematoma fluid correlates with the rate of exudation. Concentration of VEGF was determined in 51 consecutive patients with CSH by the sandwich immune enzyme-linked immunosorbent assay technique. Mean values were correlated with exudation rates taken from the literature according to the appearance of CSH on computed tomography (CT) images. The CT appearance of each CSH was classified as hypodense, isodense, hyperdense, or mixed density. Mean VEGF concentration was highest in mixed-density hematomas (22,403±4173 pg/mL; mean±standard error of the mean; n=27), followed by isodense (9715±1287 pg/mL; n=9) and hypodense (5955±610 pg/mL; n=18) hematomas. Only 1 patient with hyperdense hematoma fulfilled the inclusion criteria, and the concentration of VEGF found in this patient was 24,200 pg/mL. There was a statistically significant correlation between VEGF concentrations and exudation rates in the four classes of CT appearance (r=0.98). The current report is the first to suggest a pathophysiological link between the VEGF concentration and the exudation rate underlying the steady increase of hematoma volume and CT appearance.With this finding, the current report adds another piece of evidence in favor of the pathophysiological role of VEGF in the development of CSH, including mechanisms contributing to hematoma growth and CT appearance. PMID:24245657

  8. The diagnostic value of pleural effusion ferritin and the ratio of it to serum ferritin in differentiating exudates from transudates

    International Nuclear Information System (INIS)

    Yang Liu; Liu Junfeng; Yu Jiuru; Ju Ping; Ke Caiming

    2003-01-01

    To explore the diagnostic value of measuring the level of ferritin in pleural and peritoneal effusion for differentiating exudates from transudates, 128 effusion samples were initially detected for differentiating exudates from transudates by traditional method and Light's criteria. Ferritin in the effusions and serum ferritin were detected simultaneously, and the ratio of effusion ferritin (P Ft ) to serum ferritin (S Ft ) was counted. Based on the clinical data, the samples were divided into four groups and P Ft and P Ft /S Ft were compared. At the same time, the sensitivity and specificity of P Ft and P Ft /S Ft in differentiating exudates from transudates were compared with traditional method and Light's criteria. The results showed that in the groups of tuberculous pleurisy, non-tuberculous, benign pleurisy, and malignant tumor, the concentration of Ft in the effusions was significantly higher than that in the group of congestive heart failure and cirrhosis; and the Ft in exudates was significantly higher than that in transudates (P 0.05). If the cut-off value was set up for Ft in the effusion as 100 μg/L and P Ft /S Ft ratio as 0.5, respectively, the differentiating sensitivity and specificity were 94.2% and 87.0%, respectively. Conclusion was that the concentration of P Ft and P Ft /S Ft in exudates are higher than 100 μg/L and 0.5, respectively. On the contrary, they are lower than the cut-off level in transudates. P Ft and P Ft /S Ft have high sensitivity and high specificity in differentiating exudates from transudates, and have great diagnostic value

  9. Why rooting fails

    OpenAIRE

    Creutz, Michael

    2007-01-01

    I explore the origins of the unphysical predictions from rooted staggered fermion algorithms. Before rooting, the exact chiral symmetry of staggered fermions is a flavored symmetry among the four "tastes." The rooting procedure averages over tastes of different chiralities. This averaging forbids the appearance of the correct 't Hooft vertex for the target theory.

  10. Rooting gene trees without outgroups: EP rooting.

    Science.gov (United States)

    Sinsheimer, Janet S; Little, Roderick J A; Lake, James A

    2012-01-01

    Gene sequences are routinely used to determine the topologies of unrooted phylogenetic trees, but many of the most important questions in evolution require knowing both the topologies and the roots of trees. However, general algorithms for calculating rooted trees from gene and genomic sequences in the absence of gene paralogs are few. Using the principles of evolutionary parsimony (EP) (Lake JA. 1987a. A rate-independent technique for analysis of nucleic acid sequences: evolutionary parsimony. Mol Biol Evol. 4:167-181) and its extensions (Cavender, J. 1989. Mechanized derivation of linear invariants. Mol Biol Evol. 6:301-316; Nguyen T, Speed TP. 1992. A derivation of all linear invariants for a nonbalanced transversion model. J Mol Evol. 35:60-76), we explicitly enumerate all linear invariants that solely contain rooting information and derive algorithms for rooting gene trees directly from gene and genomic sequences. These new EP linear rooting invariants allow one to determine rooted trees, even in the complete absence of outgroups and gene paralogs. EP rooting invariants are explicitly derived for three taxon trees, and rules for their extension to four or more taxa are provided. The method is demonstrated using 18S ribosomal DNA to illustrate how the new animal phylogeny (Aguinaldo AMA et al. 1997. Evidence for a clade of nematodes, arthropods, and other moulting animals. Nature 387:489-493; Lake JA. 1990. Origin of the metazoa. Proc Natl Acad Sci USA 87:763-766) may be rooted directly from sequences, even when they are short and paralogs are unavailable. These results are consistent with the current root (Philippe H et al. 2011. Acoelomorph flatworms are deuterostomes related to Xenoturbella. Nature 470:255-260).

  11. Nasal mucosa secretion exudation response to cold air in bronchial asthma patients

    Directory of Open Access Journals (Sweden)

    Eduard V. Nekrasov

    2017-01-01

    Full Text Available Background. Combined airway hyper responsiveness to cold and hypoosmotic stimuli in asthma patients results in impairment of lung respiration function and poor disease control compared to patients with isolated airway hyper responsiveness to only one of the stimuli or without such responsiveness that can be connected with edema or mucus hypersecretion.Aim. The purpose of the study is the estimation of the processes of mucin secretion, plasma exudation and oxidative stress in response to cold air in asthma patients with combined airway responsiveness to cold and hypoosmotic stimuli using nasal mucosa as a model.Materials and methods. 23 patients with asthma participated in the study. For the nasal lavage procedure, a nasal cavity was pre-washed at least three times in 5-min intervals with 5 ml saline solution (~36 °C. A control nasal lavage was done 5 min after the last washing with a dwelling time of 1 min in the nasal cavity. Directly after the control lavage, a cold air nasal challenge was done: a participant was asked to breathe deeply at the pace of a metronome to ensure hyperventilation inhaling cold air (–20 °C through the nose and exhaling through the mouth for 5 min. Nasal lavages were taken at 1 min, 15, and 30 min after the challenge. Mucin secretion was estimated on the basis of total protein (TP content, total carbohydrates (TC, and water-soluble forms of mucins MUC5AC and MUC5B in the lavage fluids. For the estimation of plasma exudation, the concentration of α2-macroglobulin (α2-MG was measured. Oxidative stress was estimated by the content of thiobarbituric acid-reactive substances (TBARS in lavage fluid. Lung function and airway responsiveness were studied by the forced expiration spirometry method and the bronchial challenge tests with isocapnic cold air hyperventilation (CAHV and distilled water inhalation (DWI.Results. According to the bronchial challenge tests, the patients were divided into groups: 1 without airway

  12. Abscisic Acid as a Dominant Signal in Tomato During Salt Stress Predisposition to Phytophthora Root and Crown Rot

    Directory of Open Access Journals (Sweden)

    Matthew F. Pye

    2018-04-01

    Full Text Available Salt stress predisposes plants to Phytophthora root and crown rot in an abscisic acid (ABA-dependent manner. We used the tomato–Phytophthora capsici interaction to examine zoospore chemoattraction and assessed expression of pathogenesis-related (PR genes regulated by salicylic acid (SA and jasmonic acid (JA following a salt-stress episode. Although salt treatment enhances chemoattraction of tomato roots to zoospores, exudates from salt-stressed roots of ABA-deficient mutants, which do not display the predisposition phenotype, have a similar chemoattraction as exudates from salt-stressed, wild-type roots. This suggests that ABA action during predisposing stress enhances disease through effects on plant responses occurring after initial contact and during ingress by the pathogen. The expression of NCED1 (ABA synthesis and TAS14 (ABA response in roots generally corresponded to previously reported changes in root ABA levels during salt stress onset and recovery in a pattern that was not altered by infection by P. capsici. The PR genes, P4 and PI-2, hallmarks in tomato for SA and JA action, respectively, were induced in non-stressed roots during infection and strongly suppressed in infected roots exposed to salt-stress prior to inoculation. However, there was a similar proportional increase in pathogen colonization observed in salt-stressed plants relative to non-stressed plants in both wild-type and a SA-deficient nahG line. Unlike the other tomato cultivars used in this study that showed a strong predisposition phenotype, the processing tomato cv. ‘Castlemart’ and its JA mutants were not predisposed by salt. Salt stress predisposition to crown and root rot caused by P. capsici appears to be strongly conditioned by ABA-driven mechanisms in tomato, with the stress compromising SA-and JA-mediated defense-related gene expression during P. capsici infection.

  13. Fine root production at drained peatland sites

    Energy Technology Data Exchange (ETDEWEB)

    Finer, L [Finnish Forest Research Inst. (Finland). Joensuu Research Station; Laine, J [Helsinki Univ. (Finland). Dept. of Forest Ecology

    1997-12-31

    The preliminary results of the Finnish project `Carbon balance of peatlands and climate change` show that fine roots play an important role in carbon cycling on peat soils. After drainage the roots of mire species are gradually replaced by the roots of trees and other forest species. Pine fine root biomass reaches a maximum level by the time of crown closure, some 20 years after drainage on pine mire. The aim of this study is to compare the results of the sequential coring method and the ingrowth bag method used for estimating fine root production on three drained peatland sites of different fertility. The results are preliminary and continuation to the work done in the study Pine root production on drained peatlands, which is part of the Finnish project `Carbon cycling on peatlands and climate change`. In this study the fine root biomass was greater on the poor site than on the rich sites. Pine fine root production increased with the decrease in fertility. Root turnover and the production of field layer species were greater on the rich sites than on the poor site. The results suggested that the in growth bag method measured more root activity than the magnitude of production. More than two growing seasons would have been needed to balance the root dynamics in the in growth bags with the surrounding soil. That time would probably have been longer on the poor site than on the rich ones and longer for pine and field layer consisting of dwarf shrubs than for field layer consisting of sedge like species and birch. (11 refs.)

  14. Fine root production at drained peatland sites

    Energy Technology Data Exchange (ETDEWEB)

    Finer, L. [Finnish Forest Research Inst. (Finland). Joensuu Research Station; Laine, J. [Helsinki Univ. (Finland). Dept. of Forest Ecology

    1996-12-31

    The preliminary results of the Finnish project `Carbon balance of peatlands and climate change` show that fine roots play an important role in carbon cycling on peat soils. After drainage the roots of mire species are gradually replaced by the roots of trees and other forest species. Pine fine root biomass reaches a maximum level by the time of crown closure, some 20 years after drainage on pine mire. The aim of this study is to compare the results of the sequential coring method and the ingrowth bag method used for estimating fine root production on three drained peatland sites of different fertility. The results are preliminary and continuation to the work done in the study Pine root production on drained peatlands, which is part of the Finnish project `Carbon cycling on peatlands and climate change`. In this study the fine root biomass was greater on the poor site than on the rich sites. Pine fine root production increased with the decrease in fertility. Root turnover and the production of field layer species were greater on the rich sites than on the poor site. The results suggested that the in growth bag method measured more root activity than the magnitude of production. More than two growing seasons would have been needed to balance the root dynamics in the in growth bags with the surrounding soil. That time would probably have been longer on the poor site than on the rich ones and longer for pine and field layer consisting of dwarf shrubs than for field layer consisting of sedge like species and birch. (11 refs.)

  15. The dynamics of low-chlorinated benzenes in a pilot-scale constructed wetland and a hydroponic plant root mat treating sulfate-rich groundwater.

    Science.gov (United States)

    Chen, Zhongbing; Kuschk, Peter; Paschke, Heidrun; Kästner, Matthias; Köser, Heinz

    2015-03-01

    A rarely used hydroponic plant root mat filter (PRMF, of 6 m(2)) and a horizontal subsurface flow constructed wetland (HSSF CW, of 6 m(2)), operating in continuous flow and discontinuous outflow flushing modes, were investigated for treating sulfate-rich and organic carbon-lean groundwater contaminated with monochlorobenzene (MCB); 1,2-dichlorobenzene (1,2-DCB); 1,4-dichlorobenzene (1,4-DCB); and 2-chlorotoluene. Whereas the mean inflow loads ranged from 1 to 247 mg m(-2) days(-1), the range of mean inflow concentrations of the chlorobenzenes recorded over a period of 7 months was within 0.04 and 8 mg L(-1). A hydraulic surface loading rate of 30 L m(-2) days(-1) was obtained in both systems. The mean load removal efficiencies were found to vary between 87 and 93 % in the PRMF after a flow path of 4 m, while the removal efficiencies were found to range between 46 and 70 % and 71 to 73 % in the HSSF CW operating in a continuous flow mode and a discontinuous outflow flushing mode, respectively. Seasonal variations in the removal efficiencies were observed for all low-chlorinated hydrocarbons both in the PRMF and the HSSF CW, whereby the highest removal efficiencies were reached during the summer months. Sulfide formation occurred in the organic carbon-lean groundwater particularly in summer, which is probably due to the plant-derived organic carbon that fostered the microbial dissimilatory sulfate reduction. Higher redox potential in water was observed in the PRMF. In conclusion, the PRMF could be an option for the treatment of water contaminated with compounds which in particular need oxic conditions for their microbial degradation, such as in the case of low-chlorinated benzenes.

  16. Say it with flowers: Flowering acceleration by root communication.

    Science.gov (United States)

    Falik, Omer; Hoffmann, Ishay; Novoplansky, Ariel

    2014-01-01

    The timing of reproduction is a critical determinant of fitness, especially in organisms inhabiting seasonal environments. Increasing evidence suggests that inter-plant communication plays important roles in plant functioning. Here, we tested the hypothesis that flowering coordination can involve communication between neighboring plants. We show that soil leachates from Brassica rapa plants growing under long-day conditions accelerated flowering and decreased allocation to vegetative organs in target plants growing under non-inductive short-day conditions. The results suggest that besides endogenous signaling and external abiotic cues, flowering timing may involve inter-plant communication, mediated by root exudates. The study of flowering communication is expected to illuminate neglected aspects of plant reproductive interactions and to provide novel opportunities for controlling the timing of plant reproduction in agricultural settings.

  17. Cytokine concentration in aqueous humour of eyes with exudative age-related macular degeneration.

    Science.gov (United States)

    Jonas, Jost B; Tao, Yong; Neumaier, Michael; Findeisen, Peter

    2012-08-01

    To measure the concentration of cytokines in the aqueous humour of eyes with exudative age-related macular degeneration (AMD). The clinical interventional study included a study group of 18 patients with exudative AMD and a control group of 20 patients undergoing routine cataract surgery. Age did not vary significantly (p = 0.36) between study group (80.8 ± 6.4 years) and control group (77.0 ± 9.9 years), nor did gender (p = 0.75). During the interventions, aqueous humour samples were obtained, in which the concentration of cytokines was measured using a solid-phase chemiluminescence immunoassay. Macular thickness was measured by optical coherence tomography (OCT). In the study group as compared to the control group, significantly higher concentrations were measured for epithelial growth factor (EGF) (p = 0.017), human growth factor (HGF) (p= 0.048), intercellular adhesion molecule-1 (ICAM1) (p = 0.028), interleukin 12p40 (IL12p40) (p = 0.009), interleukin 1a2 (IL1a2) (p = 0.01), interleukin 3 (IL3) (p = 0.02), interleukin 6 (IL6) (p = 0.006), interleukin 8 (IL8) (p = 0.02), monocyte chemoattractant protein-1 (MCP-1) (p = 0.048), monokine induced by interferon gamma (MIG) (p = 0.016), matrix metalloproteinase 9 (MMP9) (p = 0.004) and plasminogen activator inhibitor 1 (PAI1) (p = 0.006). Macular thickness was significantly associated with the concentrations of EGF (p = 0.001), HGF (p = 0.02), ICAM1 (p = 0.001), interleukin 12p40 (p = 0.006), IL 1a2 (p = 0.002), MIG (p = 0.001), MMP9 (p < 0.001) and PAI1 (p = 0.01). Interleukin 6 and MCP-1 showed significant associations with the height of retinal pigment epithelium detachment. Numerous cytokines are associated with the presence and the amount of exudative AMD. © 2012 The Authors. Acta Ophthalmologica © 2012 Acta Ophthalmologica Scandinavica Foundation.

  18. Root-Zone Redox Dynamics - In Search for the Cause of Damage to Treated-Wastewater Irrigated Orchards in Clay Soils

    Science.gov (United States)

    Yalin, David; Shenker, Moshe; Schwartz, Amnon; Assouline, Shmuel; Tarchitzky, Jorge

    2016-04-01

    Treated wastewater (TW) has become a common source of water for agriculture. However recent findings raise concern regarding its use: a marked decrease (up to 40%) in yield appeared in orchards irrigated with TW compared with fresh water (FW) irrigated orchards. These detrimental effects appeared predominantly in orchards cultivated in clay soils. The association of the damage with clay soils rather than sandy soils led us to hypothesize that the damage is linked to soil aeration problems. We suspected that in clay soils, high sodium adsorption ratio (SAR) and high levels of organic material, both typical of TW, may jointly lead to an extreme decrease in soil oxygen levels, so as to shift soil reduction-oxidation (redox) state down to levels that are known to damage plants. Two-year continuous measurement of redox potential, pH, water tension, and oxygen were conducted in the root-zone (20-35 cm depth) of avocado trees planted in clay soil and irrigated with either TW or FW. Soil solution composition was sampled periodically in-situ and mineral composition was sampled in tree leaves and woody organs biannually. In dry periods the pe+pH values indicated oxic conditions (pe+pH>14), and the fluctuations in redox values were small in both TW and FW plots. Decreases in soil water tension following irrigation or rain were followed by drops in soil oxygen and pe+pH values. TW irrigated plots had significantly lower minimum pe+pH values compared with FW-irrigated plots, the most significant differences occurred during the irrigation season rather than the rain season. A linear correlation appeared between irrigation volume and reduction severity in TW-irrigated plots, but not in the FW plots, indicating a direct link to the irrigation regime in TW-irrigated plots. The minimum pe+pH values measured in the TW plots are indicative of suboxic conditions (9water tension and oxygen concentration levels. The consequences of our findings to plant health will be discussed, and

  19. Innate Immune Responses Activated in Arabidopsis Roots by Microbe-Associated Molecular Patterns[W][OA

    Science.gov (United States)

    Millet, Yves A.; Danna, Cristian H.; Clay, Nicole K.; Songnuan, Wisuwat; Simon, Matthew D.; Werck-Reichhart, Danièle; Ausubel, Frederick M.

    2010-01-01

    Despite the fact that roots are the organs most subject to microbial interactions, very little is known about the response of roots to microbe-associated molecular patterns (MAMPs). By monitoring transcriptional activation of β-glucuronidase reporters and MAMP-elicited callose deposition, we show that three MAMPs, the flagellar peptide Flg22, peptidoglycan, and chitin, trigger a strong tissue-specific response in Arabidopsis thaliana roots, either at the elongation zone for Flg22 and peptidoglycan or in the mature parts of the roots for chitin. Ethylene signaling, the 4-methoxy-indole-3-ylmethylglucosinolate biosynthetic pathway, and the PEN2 myrosinase, but not salicylic acid or jasmonic acid signaling, play major roles in this MAMP response. We also show that Flg22 induces the cytochrome P450 CYP71A12-dependent exudation of the phytoalexin camalexin by Arabidopsis roots. The phytotoxin coronatine, an Ile-jasmonic acid mimic produced by Pseudomonas syringae pathovars, suppresses MAMP-activated responses in the roots. This suppression requires the E3 ubiquitin ligase COI1 as well as the transcription factor JIN1/MYC2 but does not rely on salicylic acid–jasmonic acid antagonism. These experiments demonstrate the presence of highly orchestrated and tissue-specific MAMP responses in roots and potential pathogen-encoded mechanisms to block these MAMP-elicited signaling pathways. PMID:20348432

  20. Innate immune responses activated in Arabidopsis roots by microbe-associated molecular patterns.

    Science.gov (United States)

    Millet, Yves A; Danna, Cristian H; Clay, Nicole K; Songnuan, Wisuwat; Simon, Matthew D; Werck-Reichhart, Danièle; Ausubel, Frederick M

    2010-03-01

    Despite the fact that roots are the organs most subject to microbial interactions, very little is known about the response of roots to microbe-associated molecular patterns (MAMPs). By monitoring transcriptional activation of beta-glucuronidase reporters and MAMP-elicited callose deposition, we show that three MAMPs, the flagellar peptide Flg22, peptidoglycan, and chitin, trigger a strong tissue-specific response in Arabidopsis thaliana roots, either at the elongation zone for Flg22 and peptidoglycan or in the mature parts of the roots for chitin. Ethylene signaling, the 4-methoxy-indole-3-ylmethylglucosinolate biosynthetic pathway, and the PEN2 myrosinase, but not salicylic acid or jasmonic acid signaling, play major roles in this MAMP response. We also show that Flg22 induces the cytochrome P450 CYP71A12-dependent exudation of the phytoalexin camalexin by Arabidopsis roots. The phytotoxin coronatine, an Ile-jasmonic acid mimic produced by Pseudomonas syringae pathovars, suppresses MAMP-activated responses in the roots. This suppression requires the E3 ubiquitin ligase COI1 as well as the transcription factor JIN1/MYC2 but does not rely on salicylic acid-jasmonic acid antagonism. These experiments demonstrate the presence of highly orchestrated and tissue-specific MAMP responses in roots and potential pathogen-encoded mechanisms to block these MAMP-elicited signaling pathways.

  1. Anointing chemicals and ectoparasites: responses by ticks and mosquitoes to Citrus (Rutaceae) peel exudates and monoterpene constituents

    Science.gov (United States)

    Some birds and mammals rub their feathers or fur with the fruits or leaves of Citrus spp. or other Rutaceae, presumably to deter ectoparasites. We measured avoidance and other responses by the lone star tick (Amblyomma americanum) and the yellow fever mosquito (Aedes aegypti) to lemon peel exudate a...

  2. Autologous Translocation of the Retinal Pigment Epithelium and Choroid in the Treatment of Exudative Age-related Macular Degeneration

    NARCIS (Netherlands)

    K.J.M. Maaijwee (Kristel Johanna Maria)

    2008-01-01

    textabstractAge-related macular degeneration (AMD) is the most important cause of irreversible legal blindness in elderly persons in industrialized countries. AMD has two forms: atrophic (dry) and exudative (wet). In the wet form, abnormal blood vessels, arising from the choriocapillaris (choroidal

  3. Statistical modeling of nitrogen-dependent modulation of root system architecture in Arabidopsis thaliana.

    Science.gov (United States)

    Araya, Takao; Kubo, Takuya; von Wirén, Nicolaus; Takahashi, Hideki

    2016-03-01

    Plant root development is strongly affected by nutrient availability. Despite the importance of structure and function of roots in nutrient acquisition, statistical modeling approaches to evaluate dynamic and temporal modulations of root system architecture in response to nutrient availability have remained as widely open and exploratory areas in root biology. In this study, we developed a statistical modeling approach to investigate modulations of root system architecture in response to nitrogen availability. Mathematical models were designed for quantitative assessment of root growth and root branching phenotypes and their dynamic relationships based on hierarchical configuration of primary and lateral roots formulating the fishbone-shaped root system architecture in Arabidopsis thaliana. Time-series datasets reporting dynamic changes in root developmental traits on different nitrate or ammonium concentrations were generated for statistical analyses. Regression analyses unraveled key parameters associated with: (i) inhibition of primary root growth under nitrogen limitation or on ammonium; (ii) rapid progression of lateral root emergence in response to ammonium; and (iii) inhibition of lateral root elongation in the presence of excess nitrate or ammonium. This study provides a statistical framework for interpreting dynamic modulation of root system architecture, supported by meta-analysis of datasets displaying morphological responses of roots to diverse nitrogen supplies. © 2015 Institute of Botany, Chinese Academy of Sciences.

  4. Complex genetics of familial exudative vitreoretinopathy and related pediatric retinal detachments

    Science.gov (United States)

    Kondo, Hiroyuki

    2015-01-01

    Familial exudative vitreoretinopathy (FEVR) is a hereditary vitreoretinal