Immobilization of Lead Migrating from Contaminated Soil in Rhizosphere Soil of Barley (Hordeum vulgare L.) and Hairy Vetch (Vicia villosa) Using Hydroxyapatite.

PubMed

Katoh, Masahiko; Risky, Elsya; Sato, Takeshi

2017-10-23

This study conducted plant growth tests using a rhizobox system to quantitatively determine the distance of immobilization lead migrating from contaminated soil into uncontaminated rhizosphere soil, and to assess the lead phases accumulated in rhizosphere soil by sequential extraction. Without the hydroxyapatite, exchangeable lead fractions increased as the rhizosphere soil got closer to the contaminated soil. Exchangeable lead fractions were higher even in the rhizosphere soil that shares a boundary with the root surface than in the soil before being planted. Thus, plant growth of hairy vetch was lower in the soil without the hydroxyapatite than in the soil with the hydroxyapatite. The presence of hydroxyapatite may immobilize the majority of lead migrating from contaminated soil into the rhizosphere soil within 1 mm from the contaminated soil. The dominant lead fraction in the rhizosphere soil with the hydroxyapatite was residual. Thus, plant growth was not suppressed and the lead concentration of the plant shoot remained at the background level. These results indicate that the presence of hydroxyapatite in the rhizosphere soil at 5% wt may immobilize most of the lead migrating into the rhizosphere soil within 1 mm from the contaminated soil, resulting in the prevention of lead migration toward the root surface.

Immobilization of Lead Migrating from Contaminated Soil in Rhizosphere Soil of Barley (Hordeum vulgare L.) and Hairy Vetch (Vicia villosa) Using Hydroxyapatite

PubMed Central

Risky, Elsya; Sato, Takeshi

2017-01-01

This study conducted plant growth tests using a rhizobox system to quantitatively determine the distance of immobilization lead migrating from contaminated soil into uncontaminated rhizosphere soil, and to assess the lead phases accumulated in rhizosphere soil by sequential extraction. Without the hydroxyapatite, exchangeable lead fractions increased as the rhizosphere soil got closer to the contaminated soil. Exchangeable lead fractions were higher even in the rhizosphere soil that shares a boundary with the root surface than in the soil before being planted. Thus, plant growth of hairy vetch was lower in the soil without the hydroxyapatite than in the soil with the hydroxyapatite. The presence of hydroxyapatite may immobilize the majority of lead migrating from contaminated soil into the rhizosphere soil within 1 mm from the contaminated soil. The dominant lead fraction in the rhizosphere soil with the hydroxyapatite was residual. Thus, plant growth was not suppressed and the lead concentration of the plant shoot remained at the background level. These results indicate that the presence of hydroxyapatite in the rhizosphere soil at 5% wt may immobilize most of the lead migrating into the rhizosphere soil within 1 mm from the contaminated soil, resulting in the prevention of lead migration toward the root surface. PMID:29065529

External apical root resorption diagnosis by using FII human dentine fraction and salivary IGg.

PubMed

Da-Costa, Tânia Maris Pedrini Soares; Hidalgo, Mirian Marubayashi; Consolaro, Alberto; Lima, Carlos Eduardo de Oliveira; Tanaka, Evelise Ono; Itano, Eiko Nakagawa

2018-06-01

External apical root resorption as a consequence of orthodontic treatment is an inflammatory pathological process that results in permanent loss of tooth structure from the root apex. This study aimed to investigate the diagnostic potential of human dentine fractions and salivary IgG in external apical root resorption. Saliva samples were collected from 10 patients before (T0) and after 3 (T3), 6 (T6) and 12 (T12) months of orthodontic treatment. The total dentinal extract, obtained from human third molars, was fractioned by gel filtration chromatography in three fractions denominated FI, FII and FIII. The root resorption analysis of the upper central incisors was performed by digital image subtraction method. Reactivity of salivary IgG to antigenic fractions of dentine was determined by enzyme-linked immunosorbent assay (Elisa). Regardless of treatment, FI dentin fraction with high MM (<300kDa) was the one that presented highest reactivity with salivary IgG. However, it was found higher salivary IgG reactivity for FII (69 to 45 kilodalton [kDa]) as compared to FIII (<45kDa) at (T6) and (T12), (P<0.05), the same periods in that the root resorptions were detected. Our results suggest that FII human dentine fraction and salivary IgG have potential to be used in diagnosis and monitoring of external apical root resorption. The development of a practical and accessible biochemical test using saliva and FII dentine fraction may help in the prevention of severe root resorption. Copyright © 2018. Published by Elsevier Masson SAS.

Modeling electron fractionalization with unconventional Fock spaces.

PubMed

Cobanera, Emilio

2017-08-02

It is shown that certain fractionally-charged quasiparticles can be modeled on D-dimensional lattices in terms of unconventional yet simple Fock algebras of creation and annihilation operators. These unconventional Fock algebras are derived from the usual fermionic algebra by taking roots (the square root, cubic root, etc) of the usual fermionic creation and annihilation operators. If the fermions carry non-Abelian charges, then this approach fractionalizes the Abelian charges only. In particular, the mth-root of a spinful fermion carries charge e/m and spin 1/2. Just like taking a root of a complex number, taking a root of a fermion yields a mildly non-unique result. As a consequence, there are several possible choices of quantum exchange statistics for fermion-root quasiparticles. These choices are tied to the dimensionality [Formula: see text] of the lattice by basic physical considerations. One particular family of fermion-root quasiparticles is directly connected to the parafermion zero-energy modes expected to emerge in certain mesoscopic devices involving fractional quantum Hall states. Hence, as an application of potential mesoscopic interest, I investigate numerically the hybridization of Majorana and parafermion zero-energy edge modes caused by fractionalizing but charge-conserving tunneling.

The Extract of Roots of Sophora flavescens Enhances the Recovery of Motor Function by Axonal Growth in Mice with a Spinal Cord Injury

PubMed Central

Tanabe, Norio; Kuboyama, Tomoharu; Kazuma, Kohei; Konno, Katsuhiro; Tohda, Chihiro

2016-01-01

Although axonal extension to reconstruct spinal tracts should be effective for restoring function after spinal cord injury (SCI), chondroitin sulfate proteoglycan (CSPG) levels increase at spinal cord lesion sites, and inhibit axonal regrowth. In this study, we found that the water extract of roots of Sophora flavescens extended the axons of mouse cortical neurons, even on a CSPG-coated surface. Consecutive oral administrations of S. flavescens extract to SCI mice for 31 days increased the density of 5-HT-positive axons at the lesion site and improved the motor function. Further, the active constituents in the S. flavescens extract were identified. The water and alkaloid fractions of the S. flavescens extract each exhibited axonal extension activity in vitro. LC/MS analysis revealed that these fractions mainly contain matrine and/or oxymatrine, which are well-known major compounds in S. flavescens. Matrine and oxymatrine promoted axonal extension on the CSPG-coated surface. This study is the first to demonstrate that S. flavescens extract, matrine, and oxymatrine enhance axonal growth in vitro, even on a CSPG-coated surface, and that S. flavescens extract improves motor function and increases axonal density in SCI mice. PMID:26834638

Explicit Formulae for the Continued Fraction Convergents of "Square Root of D"

ERIC Educational Resources Information Center

Braza, Peter A.

2010-01-01

The formulae for the convergents of continued fractions are always given recursively rather than in explicit form. This article derives explicit formulae for the convergents of the continued fraction expansions for square roots.

Antibacterial activity of Artocarpus heterophyllus.

PubMed

Khan, M R; Omoloso, A D; Kihara, M

2003-07-01

The crude methanolic extracts of the stem and root barks, stem and root heart-wood, leaves, fruits and seeds of Artocarpus heterophyllus and their subsequent partitioning with petrol, dichloromethane, ethyl acetate and butanol gave fractions that exhibited a broad spectrum of antibacterial activity. The butanol fractions of the root bark and fruits were found to be the most active. None of the fractions were active against the fungi tested.

Fractionation of metal stable isotopes by higher plants

USGS Publications Warehouse

Von Blanckenburg, F.; Von Wiren, N.; Guelke, M.; Weiss, D.J.; Bullen, T.D.

2009-01-01

Higher plants induce chemical reactions in the rhizosphere, facilitating metal uptake by roots. Fractionation of the isotopes in nutrients such as calcium, iron, magnesium, and zinc produces a stable isotope composition in the plants that generally differs from that of the growth medium. Isotope fractionation also occurs during transport of the metals within most plants, but its extent depends on plant species and on the metal, in particular, on the metal's redox state and what ligand it is bound to. The metal stable isotope variations observed in plants create an isotope signature of life at the Earth's surface, contributing substantially to our understanding of metal cycling processes in the environment and in individual organisms.

Phytotoxic substances in runoff from forested catchment areas

NASA Astrophysics Data System (ADS)

Grimvall, Anders; Bengtsson, Maj-Britt; Borén, Hans; Wahlström, Dan

Runoff from different catchment areas in southern Sweden was tested in a root bioassay based on solution cultures of cucumber seedlings. Water samples from agricultural catchment areas produced no signs at all or only weak signs of inhibited root growth, whereas several water samples from catchment areas dominated by mires or coniferous forests produced visible root injuries. The most severe root injuries (very short roots, discolouration, swelling of root tips and lack of root hairs) were caused by samples from a catchment area without local emissions and dominated by old stands of spruce. Fractionation by ultrafiltration showed that the phytotoxic effect of these samples could be attributed to organic matter with a nominal molecular-weight exceeding 1000 or to substances associated with organic macromolecules. Experiments aimed at concentrating phytotoxic compounds from surface water indicated that the observed growth inhibition was caused by strongly hydrophilic substances. Previous reports on phytotoxic, organic substances of natural origin have emphasized interaction between plants growing close together. The presence of phytotoxic substances in runoff indicates that there is also a large-scale dispersion of such compounds.

The unseen iceberg: Plant roots in arctic tundra

USGS Publications Warehouse

Iverson, Colleen M.; Sloan, Victoria L.; Sullivan, Patrick F.; Euskirchen, E.S.; McGuire, A. David; Norby, Richard J.; Walker, Anthony P.; Warren, Jeffrey M.; Wullschleger, Stan D.

2015-01-01

Plant roots play a critical role in ecosystem function in arctic tundra, but root dynamics in these ecosystems are poorly understood. To address this knowledge gap, we synthesized available literature on tundra roots, including their distribution, dynamics and contribution to ecosystem carbon and nutrient fluxes, and highlighted key aspects of their representation in terrestrial biosphere models. Across all tundra ecosystems, belowground plant biomass exceeded aboveground biomass, with the exception of polar desert tundra. Roots were shallowly distributed in the thin layer of soil that thaws annually, and were often found in surface organic soil horizons. Root traits – including distribution, chemistry, anatomy and resource partitioning – play an important role in controlling plant species competition, and therefore ecosystem carbon and nutrient fluxes, under changing climatic conditions, but have only been quantified for a small fraction of tundra plants. Further, the annual production and mortality of fine roots are key components of ecosystem processes in tundra, but extant data are sparse. Tundra root traits and dynamics should be the focus of future research efforts. Better representation of the dynamics and characteristics of tundra roots will improve the utility of models for the evaluation of the responses of tundra ecosystems to changing environmental conditions.

Distinct Litter Stabilization Dynamics Pathways for Decomposition of Pine Needle and Fine Root Within Soil

NASA Astrophysics Data System (ADS)

Mambelli, S.; Filley, T. R.; Bird, J.; Dawson, T.; Torn, M. S.

2008-12-01

The chemical composition of litter imparts a strong control on the initial rates of microbial decay but it is unclear how plant chemistry influences the ultimate stabilization of soil organic matter (SOM) and the nature of the products stabilized. We determined the concentration and 13C enrichment of lignin phenols and substituted fatty acids (SFA) in SOM fractions from an experiment in which 13C- and 15N-labeled needles or fine roots were added to the mineral soil in a Ponderosa pine (Pinus ponderosa) forest in the Sierra Nevada, CA, USA. 1.5 y after litter addition, we analyzed bulk soil (< 2 mm), free light fraction (LF, mean residence time (MRT) ~5 y) and alkali/acid insoluble humin (MRT ~270 y) fractions. Needles contained nearly 2 and 3x the lignin and SFA content per organic carbon unit as did roots. Lignin and SFA decreased from the free LF to the bulk soil to the humin fraction; and molecular properties were more similar within a SOM fraction regardless of the litter source. However, LF and humin from the root addition contained more lignin than from the needle addition. Based upon the relative movement of litter-derived 13C and 15N into SOM fractions during 1.5 y, it was proposed that the 13C accumulation in the humin fraction for needles was derived from high C/N, needle-derived biopolymer molecular fragments that are surficially associated with particles. In contrast, the root-derived material entering SOM fractions was much lower in C/N and was likely from microbial by-products. Consistent with this hypothesis, both lignin and SFA in the LF and humin fractions amended with enriched needles were highly enriched (+ 30-60 permil) with respect to the SOM fractions from soils amended with roots. These differences were large even considering the lower concentration of SFA and lignin in root material. Although the chemistry and MRT of LF and humin were dramatically different, the extent of 13C-enrichment among lignin and SFA were comparable for the needle experiment while most lignin phenols for the humin from the root addition had greater 13C content than SFA. This indicates that molecular fragments of plant biopolymers can readily associate with both labile and stabilized SOM fractions. At the same time, these results suggest that distinct decomposition and stabilization pathways exist for litters, such as needles vs. roots, of different chemical quality.

GC-MS profile of antimicrobial and antioxidant fractions from Cordia rothii roots.

PubMed

Khan, Kehkashan; Firdous, Sadiqa; Ahmad, Aqeel; Fayyaz, Nida; Nadir, Muhammad; Rasheed, Munawwer; Faizi, Shaheen

2016-11-01

An ethnobotanical survey of Cordia rothii Roem. & Schult. (Boraginaceae) reveals it as a medicinal plant. Antimicrobial and antioxidant potential evaluation and identification of chemical constituents via GC-MS of C. rothii roots fractions. To the best of our knowledge, this is the first systematic investigation of the roots exploiting GC-MS. Extraction and fractionation of C. rothii roots furnished various fractions using solvents of varying polarity, i.e., n-hexane, chloroform, ethyl acetate, acetone and methanol. In vitro antimicrobial and antioxidant screening was performed using disk diffusion and DPPH methods, respectively. MIC of active fractions was also determined using disk diffusion method. GC-MS was used to identify constituents which may be responsible for these activities. Among various fractions from C. rothii roots, fraction KA-C showed strong antibacterial activity against 17 microorganisms tested, with MIC ranging from 250-31.25 μg/mL. Fractions KA-A, KM and KM-A exhibited significant antioxidant potential with EC 50 46.875 μg/mL, while fractions KEA-PE, KM-PE and KM-M were good with EC 50 93.750 μg/mL. Forty-five phytochemicals were identified in GC-MS studies including eight hydrocarbons, six free fatty acids, 11 fatty acids esters, two phenylpropanoids, four aromatics, four terpenoid quinones/hydroquinones, three triterpenes, four phytosterols, two hexose metabolites and a DNA base. Of these, 32 constituents have been reported for the first time from C. rothii, 24 from genus Cordia and 15 from Boraginaceae. Strong antibacterial and antioxidant potential of C. rothii roots may be due to the contribution of phytoconstituents identified through GC-MS studies.

The low-molecular-weight fraction of exopolysaccharide II from Sinorhizobium meliloti is a crucial determinant of biofilm formation.

PubMed

Rinaudi, Luciana V; González, Juan E

2009-12-01

Sinorhizobium meliloti is a soil bacterium that elicits the formation of root organs called nodules on its host plant, Medicago sativa. Inside these structures, the bacteria are able to convert atmospheric nitrogen into ammonia, which is then used by the plant as a nitrogen source. The synthesis by S. meliloti of at least one exopolysaccharide, succinoglycan or EPS II, is essential for a successful symbiosis. While exopolysaccharide-deficient mutants induce the formation of nodules, they fail to invade them, and as a result, no nitrogen fixation occurs. Interestingly, the low-molecular-weight fractions of these exopolysaccharides are the symbiotically active forms, and it has been suggested that they act as signals to the host plant to initiate infection thread formation. In this work, we explored the role of these rhizobial exopolysaccharides in biofilm formation and their importance in the symbiotic relationship with the host. We showed that the ExpR/Sin quorum-sensing system controls biofilm formation in S. meliloti through the production of EPS II, which provides the matrix for the development of structured and highly organized biofilms. Moreover, the presence of the low-molecular-weight fraction of EPS II is vital for biofilm formation, both in vitro and in vivo. This is the first report where the symbiotically active fraction of EPS II is shown to be a critical factor for biofilm formation and root colonization. Thus, the ability of S. meliloti to properly attach to root surfaces and form biofilms conferred by the synthesis of exopolysaccharides may embody the main function of these symbiotically essential molecules.

Chemical composition, antioxidant and antigenotoxic activities of different fractions of Gentiana asclepiadea L. roots extract

PubMed Central

Mihailovic, Vladimir; Matic, Sanja; Mišic, Danijela; Solujic, Slavica; Stanic, Snežana; Katanic, Jelena; Mladenovic, Milan; Stankovic, Nevena

2013-01-01

The aim of this study was to evaluate the antioxidant and antigenotoxic activities of chloroform, ethyl acetate and n-butanol fractions obtained from Gentiana asclepiadea L. roots methanolic extract. The main secondary metabolites sweroside, swertiamarin and gentiopicrine were quantified in G. asclepiadea root extracts using HPLC-DAD analysis. Amount of total phenols, flavonoids, flavonols and gallotannins was also determined. The antigenotoxic potential of extracts from roots of G. asclepiadea was assessed using the standard in vivo procedure for the detection of sex linked recessive lethal mutations in Drosophila melanogaster males treated with ethyl methanesulfonate (EMS). The results showed that the most abundant secoiridoid in G. asclepiadea roots was gentiopicrine and its content in the n-butanol fraction (442.89 mg/g) was the highest. Among all extracts, ethyl acetate fraction showed the highest antioxidant activity, as well as total phenolics (146.64 GAE/g), flavonoids (44.62 RUE/g), flavonols (22.71 RUE/g) and gallotannins (0.99 mg GAE/g) content. All the fractions showed antioxidant activity using in vitro model systems and the results have been correlated with total phenolics, flavonoids, flavonols and gallotannins content. In addition to antioxidant activity, G. asclepiadea root extract fractions possess an antigenotoxic effect against DNA damage induced by alkylation with EMS. The antioxidant activity exhibited by G. asclepiadea depended on the phenolic compounds content of the tested extracts, while there was no significant difference in the antigenotoxic potential between fractions. PMID:26622219

Micropore surface area of alkali-soluble plant macromolecules (humic acids) drives their decomposition rates in soil.

PubMed

Papa, Gabriella; Spagnol, Manuela; Tambone, Fulvia; Pilu, Roberto; Scaglia, Barbara; Adani, Fabrizio

2010-02-01

Previous studies suggested that micropore surface area (MSA) of alkali-soluble bio-macromolecules of aerial plant residues of maize constitutes an important factor that explains their humification in soil, that is, preservation against biological degradation. On the other hand, root plant residue contributes to the soil humus balance, as well. Following the experimental design used in a previous paper published in this journal, this study shows that the biochemical recalcitrance of the alkali-soluble acid-insoluble fraction of the root plant material, contributed to the root maize humification of both Wild-type maize plants and its corresponding mutant brown midrib (bm3), this latter characterized by reduced lignin content. Humic acids (HAs) existed in root (root-HAs) were less degraded in soil than corresponding HAs existed in shoot (shoot-HAs): shoot-HAs bm3 (48%)>shoot-HAs Wild-type (37%)>root-HAs Wild-type (33%)>root-HAs bm3 (22%) (degradability shown in parenthesis). These differences were related to the MSA of HAs, that is, root-HAs having a higher MSA than shoot-HAs: shoot-HAs bm3 (41.43+/-1.2m(2)g(-1))

Relationship between metal speciation in soil solution and metal adsorption at the root surface of ryegrass.

PubMed

Kalis, Erwin J J; Temminghoff, Erwin J M; Town, Raewyn M; Unsworth, Emily R; van Riemsdijk, Willem H

2008-01-01

The total metal content of the soil or total metal concentration in the soil solution is not always a good indicator for metal availability to plants. Therefore, several speciation techniques have been developed that measure a defined fraction of the total metal concentration in the soil solution. In this study the Donnan Membrane Technique (DMT) was used to measure free metal ion concentrations in CaCl(2) extractions (to mimic the soil solution, and to work under standardized conditions) of 10 different soils, whereas diffusive gradients in thin-films (DGT) and scanning chronopotentiometry (SCP) were used to measure the sum of free and labile metal concentrations in the CaCl(2) extracts. The DGT device was also exposed directly to the (wetted) soil (soil-DGT). The metal concentrations measured with the speciation techniques are related to the metal adsorption at the root surface of ryegrass (Lolium perenne L.), to be able to subsequently predict metal uptake. In most cases the metal adsorption related pH-dependently to the metal concentrations measured by DMT, SCP, and DGT in the CaCl(2) extract. However, the relationship between metal adsorption at the root surface and the metal concentrations measured by the soil-DGT was not-or only slightly-pH dependent. The correlations between metal adsorption at the root surface and metal speciation detected by different speciation techniques allow discussion about rate limiting steps in biouptake and the contribution of metal complexes to metal bioavailability.

Effects of boiling and frying on the bioaccessibility of beta-carotene in yellow-fleshed cassava roots (Manihot esculenta Crantz cv. BRS Jari).

PubMed

Gomes, Suellen; Torres, Alexandre Guedes; Godoy, Ronoel; Pacheco, Sidney; Carvalho, José; Nutti, Marília

2013-03-01

The effects of boiling and frying on the bioaccessibility of all-trans-beta-carotene in biofortified BRS Jari cassava roots have not been investigated, although these are conventional methods of cassava preparation. The aims of the present study were to investigate beta-carotene micellarization efficiency of yellow-fleshed BRS Jari cassava roots after boiling and frying, as an indicator of the bioaccessibility of this carotenoid, and to apply fluorescence microscopy to investigate beta-carotene in the emulsified fraction. Uncooked, boiled, and fried cassava roots were digested in vitro for the evaluation, by reversed-phase high-performance liquid chromatography (HPLC), of the efficiency of micellarization of all-trans-beta-carotene in BRS Jari cassava roots. Fluorescence microscopy of the micellar fraction was used to confirm the presence of beta-carotene in the emulsified fraction and to observe the structure of the microemulsion from the boiled and fried cassava samples. Fried cassava roots showed the highest (p < .05) micellarization efficiency for total carotenoids and all-trans-beta-carotene (14.1 +/- 2.25% and 14.37 +/- 2.44%, respectively), compared with boiled and raw samples. Fluorescence microscopy showed that after in vitro digestion there were no carotenoid crystals in the micellar fraction, but rather that this fraction presented a biphasic system compatible with emulsified carotenoids, which was consistent with the expected high bioavailability of beta-carotene in this fraction. Increased emulsification and bioaccessibility of beta-carotene from fried biofortified BRS Jari cassava roots compensates for chemical losses during preparation, indicating that this preparation is suitable for home use of BRS Jari cassava roots and might represent a relatively good food source of bioavailable provitamin A.

Iron isotope fingerprints of redox and biogeochemical cycling in the soil-water-rice plant system of a paddy field.

PubMed

Garnier, J; Garnier, J-M; Vieira, C L; Akerman, A; Chmeleff, J; Ruiz, R I; Poitrasson, F

2017-01-01

The iron isotope composition was used to investigate dissimilatory iron reduction (DIR) processes in an iron-rich waterlogged paddy soil, the iron uptake strategies of plants and its translocation in the different parts of the rice plant along its growth. Fe concentration and isotope composition (δ 56 Fe) in irrigation water, precipitates from irrigation water, soil, pore water solution at different depths under the surface water, iron plaque on rice roots, rice roots, stems, leaves and grains were measured. Over the 8.5-10cm of the vertical profiles investigated, the iron pore water concentration (0.01 to 24.3mg·l -1 ) and δ 56 Fe (-0.80 to -3.40‰) varied over a large range. The significant linear co-variation between Ln[Fe] and δ 56 Fe suggests an apparent Rayleigh-type behavior of the DIR processes. An average net fractionation factor between the pore water and the soil substrate of Δ 56 Fe≈-1.15‰ was obtained, taking the average of all the δ 56 Fe values weighted by the amount of Fe for each sample. These results provide a robust field study confirmation of the conceptual model of Crosby et al. (2005, 2007) for interpreting the iron isotope fractionation observed during DIR, established from a series of laboratories experiments. In addition, the strong enrichment of heavy Fe isotope measured in the root relative to the soil solution suggest that the iron uptake by roots is more likely supplied by iron from plaque and not from the plant-available iron in the pore water. Opposite to what was previously observed for plants following strategy II for iron uptake from soils, an iron isotope fractionation factor of -0.9‰ was found from the roots to the rice grains, pointing to isotope fractionation during rice plant growth. All these features highlight the insights iron isotope composition provides into the biogeochemical Fe cycling in the soil-water-rice plant systems studied in nature. Copyright © 2016 Elsevier B.V. All rights reserved.

Operationally Defined Apoplastic and Symplastic Aluminum Fractions in Root Tips of Aluminum-Intoxicated Wheat

PubMed Central

Tice, Kathy R.; Parker, David R.; DeMason, Darleen A.

1992-01-01

Knowledge of the mechanistic basis of differential aluminum (Al) tolerance depends, in part, on an improved ability to quantify Al located in the apoplastic and symplastic compartments of the root apex. Using root tips excised from seedlings of an Al-tolerant wheat cultivar (Triticum aestivum L. cv Yecora Rojo) grown in Al solutions for 2 d, we established an operationally defined apoplastic Al fraction determined with six sequential 30-min washes using 5 mm CaCl2 (pH 4.3). Soluble symplastic Al was eluted by freezing root tips to rupture cell membranes and performing four additional 30-min CaCl2 washes, and a residual fraction was determined via digestion of root tips with HNO3. The three fractions were then determined in Yecora Rojo and a sensitive wheat cultivar (Tyler) grown at 18, 55, or 140 μm total solution Al (AlT). When grown at equal AlT, Tyler contained more Al than Yecora Rojo in all fractions, but both total Al and fractional distribution were similar in the two cultivars grown at AlT levels effecting a 50% reduction in root growth. Residual Al was consistently 50 to 70% of the total, and its location was elucidated by staining root tips with the fluorophore morin and examining them using fluorescence and confocal laser scanning microscopy. Wall-associated Al was only observed in tips prior to any washing, and the residual fraction was manifested as distinct staining of the cytoplasm and nucleus but not of the apoplastic space. Accordingly, the residual fraction was allocated to the symplastic compartment for both cultivars, and recalculated apoplastic Al was consistently approximately 30 to 40% of the total. Distributions of Al in the two cultivars did not support a symplastic detoxification hypothesis, but the role of cytoplasmic exclusion remains unsettled. Images Figure 4 Figure 5 PMID:16652962

Calcium isotope fractionation between aqueous compounds relevant to low-temperature geochemistry, biology and medicine

NASA Astrophysics Data System (ADS)

Moynier, Frédéric; Fujii, Toshiyuki

2017-03-01

Stable Ca isotopes are fractionated between bones, urine and blood of animals and between soils, roots and leaves of plants by >1000 ppm for the 44Ca/40Ca ratio. These isotopic variations have important implications to understand Ca transport and fluxes in living organisms; however, the mechanisms of isotopic fractionation are unclear. Here we present ab initio calculations for the isotopic fractionation between various aqueous species of Ca and show that this fractionation can be up to 3000 ppm. We show that the Ca isotopic fractionation between soil solutions and plant roots can be explained by the difference of isotopic fractionation between the different first shell hydration degree of Ca2+ and that the isotopic fractionation between roots and leaves is controlled by the precipitation of Ca-oxalates. The isotopic fractionation between blood and urine is due to the complexation of heavy Ca with citrate and oxalates in urine. Calculations are presented for additional Ca species that may be useful to interpret future Ca isotopic measurements.

Biochemical Changes in Terminal Root Galls Caused by an Ectoparasitic Nematode, Longidorus africanus: Amino Acids.

PubMed

Epstein, E; Cohn, E

1971-10-01

The amino acids of terminal root galls caused by Longidorus africanus on bur marigold (Bidens tripartita L.) and grapevine (Vitis vinifera L.) were studied. The galled roots of bur marigold contained 73% more cell-wall protein and 184% more free amino acids. The main changes among the free amino acids of the galled tissue were a large increase (1900%) in proline and a decrease in aspartic acid (56%) compared with the respective check tissue. Hydroxyproline decreased in the wall protein fraction from 5.6% in the healthy tissue to 3.6% in the infected tissue.Percent of hydroxyproline in total amino acids of the wall protein fraction of grapevine roots decreased from 0.7% in the healthy tissue to 0.3% in the galled tissue, and total proteins of this fraction decreased from 9.5 mg to 4.5 rag, respectively. Total protein in the protoplasmic fraction also decreased from 3.0 mg in healthy to 1.0 mg in infected roots. No change was noticed in total proteins in the free amino acids fraction but free proline decreased 40% in the infected roots.The relationship of these differences to the specific reactions of the hosts to nematode feeding is discussed.

Distribution of polycyclic aromatic hydrocarbons in subcellular root tissues of ryegrass (Lolium multiflorum Lam.)

PubMed Central

2010-01-01

Background Because of the increasing quantity and high toxicity to humans of polycyclic aromatic hydrocarbons (PAHs) in the environment, several bioremediation mechanisms and protocols have been investigated to restore PAH-contaminated sites. The transport of organic contaminants among plant cells via tissues and their partition in roots, stalks, and leaves resulting from transpiration and lipid content have been extensively investigated. However, information about PAH distributions in intracellular tissues is lacking, thus limiting the further development of a mechanism-based phytoremediation strategy to improve treatment efficiency. Results Pyrene exhibited higher uptake and was more recalcitrant to metabolism in ryegrass roots than was phenanthrene. The kinetic processes of uptake from ryegrass culture medium revealed that these two PAHs were first adsorbed onto root cell walls, and they then penetrated cell membranes and were distributed in intracellular organelle fractions. At the beginning of uptake (< 50 h), adsorption to cell walls dominated the subcellular partitioning of the PAHs. After 96 h of uptake, the subcellular partition of PAHs approached a stable state in the plant water system, with the proportion of PAH distributed in subcellular fractions being controlled by the lipid contents of each component. Phenanthrene and pyrene primarily accumulated in plant root cell walls and organelles, with about 45% of PAHs in each of these two fractions, and the remainder was retained in the dissolved fraction of the cells. Because of its higher lipophilicity, pyrene displayed greater accumulation factors in subcellular walls and organelle fractions than did phenanthrene. Conclusions Transpiration and the lipid content of root cell fractions are the main drivers of the subcellular partition of PAHs in roots. Initially, PAHs adsorb to plant cell walls, and they then gradually diffuse into subcellular fractions of tissues. The lipid content of intracellular components determines the accumulation of lipophilic compounds, and the diffusion rate is related to the concentration gradient established between cell walls and cell organelles. Our results offer insights into the transport mechanisms of PAHs in ryegrass roots and their diffusion in root cells. PMID:20860818

Community composition of ammonia-oxidizing bacteria and archaea in rice field soil as affected by nitrogen fertilization.

PubMed

Wang, Yanan; Ke, Xiubin; Wu, Liqin; Lu, Yahai

2009-02-01

Little information is available on the ecology of ammonia-oxidizing bacteria (AOB) and archaea (AOA) in flooded rice soils. Consequently, a microcosm experiment was conducted to determine the effect of nitrogen fertilizer on the composition of AOB and AOA communities in rice soil by using molecular analyses of ammonia monooxygenase gene (amoA) fragments. Experimental treatments included three levels of N (urea) fertilizer, i.e. 50, 100 and 150 mgNkg(-1) soil. Soil samples were operationally divided into four fractions: surface soil, bulk soil deep layer, rhizosphere and washed root material. NH(4)(+)-N was the dominant form of N in soil porewater and increased with N fertilization. Cloning and sequencing of amoA gene fragments showed that the AOB community in the rice soil consisted of three major groups, i.e. Nitrosomonas communis cluster, Nitrosospira cluster 3a and cluster 3b. The sequences related to Nitrosomonas were predominant. There was a clear effect of N fertilizer and soil depth on AOB community composition based on terminal restriction fragment length polymorphism fingerprinting. Nitrosomonas appeared to be more abundant in the potentially oxic or micro-oxic fractions, including surface soil, rhizosphere and washed root material, than the deep layer of anoxic bulk soil. Furthermore, Nitrosomonas increased relatively in the partially oxic fractions and that of Nitrosospira decreased with the increasing application of N fertilizer. However, AOA community composition remained unchanged according to the denaturing gradient gel electrophoresis analyses.

The unseen iceberg: plant roots in arctic tundra.

PubMed

Iversen, Colleen M; Sloan, Victoria L; Sullivan, Patrick F; Euskirchen, Eugenie S; McGuire, A David; Norby, Richard J; Walker, Anthony P; Warren, Jeffrey M; Wullschleger, Stan D

2015-01-01

Plant roots play a critical role in ecosystem function in arctic tundra, but root dynamics in these ecosystems are poorly understood. To address this knowledge gap, we synthesized available literature on tundra roots, including their distribution, dynamics and contribution to ecosystem carbon and nutrient fluxes, and highlighted key aspects of their representation in terrestrial biosphere models. Across all tundra ecosystems, belowground plant biomass exceeded aboveground biomass, with the exception of polar desert tundra. Roots were shallowly distributed in the thin layer of soil that thaws annually, and were often found in surface organic soil horizons. Root traits - including distribution, chemistry, anatomy and resource partitioning - play an important role in controlling plant species competition, and therefore ecosystem carbon and nutrient fluxes, under changing climatic conditions, but have only been quantified for a small fraction of tundra plants. Further, the annual production and mortality of fine roots are key components of ecosystem processes in tundra, but extant data are sparse. Tundra root traits and dynamics should be the focus of future research efforts. Better representation of the dynamics and characteristics of tundra roots will improve the utility of models for the evaluation of the responses of tundra ecosystems to changing environmental conditions. No claim to original US Government works New Phytologist © 2014 New Phytologist Trust.

Evaluation of phytochemical content, antimicrobial, cytotoxic and antitumor activities of extract from Rumex hastatus D. Don roots.

PubMed

Sahreen, Sumaira; Khan, Muhammad Rashid; Khan, Rahmat Ali; Hadda, Taibi Ben

2015-07-03

Being a part of Chinese as well as ayurdic herbal system, roots of Rumex hastatus D. Don (RH) is highly medicinal, used to regulated blood pressure. It is also reported that the plant is diuretic, laxative, tonic, used against microbial skin diseases, bilious complaints and jaundice. The present study is conducted to evaluate phytochemical, antimicrobial, antitumor and cytotoxic activities of extract obtained from R. hastatus roots. RH roots were powdered and extracted with methanol to get crude extract. Crude extract was further fractioned on the basis of increasing polarity, with n-hexane (HRR), chloroform (CRR), ethyl acetate (ERR), n-butanol (BRR) and residual aqueous fraction (ARR). Methanol extract and its derived fractions were subjected to phytochemical screening and assayed for antibacterial activities via agar well diffusion method. Antifungal activities were checked through agar tube dilution method whereas potato disc assay was employed for the determination of antitumor activity. On the other hand cytotoxic activities were conducted using brine shrimps procedures. The results obtained from phytochemical analysis indicate the presence of alkaloids, anthraquinones, flavonoids and saponins in all the fractions. Most of the plant fractions showed substantial antimicrobial activities, which is in accordance with the spacious use of tested plant samples in primary healthcare center. Fractions of R. hastatus roots for cytotoxicity were tested as an effective cytotoxic was found as BRR > MRR > CRR > ARR > ERR > HRR. Ranking order of fractions of R. hastatus roots for effective antitumor screening was found as MRR > BRR > ARR > CRR > ERR > HRR. These results showed that R. hastatus appeared as an important source for the discovery of new antimicrobial drugs and antitumor agents; verify its traditional uses and its exploitation as therapeutic agent.

a New Method for Calculating the Fractal Dimension of Surface Topography

NASA Astrophysics Data System (ADS)

Zuo, Xue; Zhu, Hua; Zhou, Yuankai; Li, Yan

2015-06-01

A new method termed as three-dimensional root-mean-square (3D-RMS) method, is proposed to calculate the fractal dimension (FD) of machined surfaces. The measure of this method is the root-mean-square value of surface data, and the scale is the side length of square in the projection plane. In order to evaluate the calculation accuracy of the proposed method, the isotropic surfaces with deterministic FD are generated based on the fractional Brownian function and Weierstrass-Mandelbrot (WM) fractal function, and two kinds of anisotropic surfaces are generated by stretching or rotating a WM fractal curve. Their FDs are estimated by the proposed method, as well as differential boxing-counting (DBC) method, triangular prism surface area (TPSA) method and variation method (VM). The results show that the 3D-RMS method performs better than the other methods with a lower relative error for both isotropic and anisotropic surfaces, especially for the surfaces with dimensions higher than 2.5, since the relative error between the estimated value and its theoretical value decreases with theoretical FD. Finally, the electrodeposited surface, end-turning surface and grinding surface are chosen as examples to illustrate the application of 3D-RMS method on the real machined surfaces. This method gives a new way to accurately calculate the FD from the surface topographic data.

Evaluation of antioxidant activity and characterization of phenolic constituents of Phyllanthus amarus root.

PubMed

Maity, Soumya; Chatterjee, Suchandra; Variyar, Prasad Shekhar; Sharma, Arun; Adhikari, Soumyakanti; Mazumder, Santasree

2013-04-10

The antioxidant property of the 70% aqueous ethanol extract of Phyllanthus amarus roots and its ether-soluble, ethyl acetate-soluble, and aqueous fractions were investigated by various in vitro assays. The root extracts showed higher DPPH, hydroxyl, superoxide, and nitric oxide radical scavenging and reducing power activity. Among all the samples, the ethyl acetate-soluble fraction demonstrated highest radical scavenging activity and total phenolics content. Twenty-eight different phenolic compounds were identified by LCMS/MS analysis of the ethyl acetate-soluble fraction. The majority of the compounds were found to exist as their glycosides, and many of these were gallic acid derivatives. Free epicatechin and gallic acid were also identified in the ethyl acetate-soluble fraction. The present investigation suggested that P. amarus root is a potent antioxidant and can be used for the prevention of diseases related to oxidative stress.

High-resolution synchrotron imaging shows that root hairs influence rhizosphere soil structure formation.

PubMed

Koebernick, Nicolai; Daly, Keith R; Keyes, Samuel D; George, Timothy S; Brown, Lawrie K; Raffan, Annette; Cooper, Laura J; Naveed, Muhammad; Bengough, Anthony G; Sinclair, Ian; Hallett, Paul D; Roose, Tiina

2017-10-01

In this paper, we provide direct evidence of the importance of root hairs on pore structure development at the root-soil interface during the early stage of crop establishment. This was achieved by use of high-resolution (c. 5 μm) synchrotron radiation computed tomography (SRCT) to visualise both the structure of root hairs and the soil pore structure in plant-soil microcosms. Two contrasting genotypes of barley (Hordeum vulgare), with and without root hairs, were grown for 8 d in microcosms packed with sandy loam soil at 1.2 g cm -3 dry bulk density. Root hairs were visualised within air-filled pore spaces, but not in the fine-textured soil regions. We found that the genotype with root hairs significantly altered the porosity and connectivity of the detectable pore space (> 5 μm) in the rhizosphere, as compared with the no-hair mutants. Both genotypes showed decreasing pore space between 0.8 and 0.1 mm from the root surface. Interestingly the root-hair-bearing genotype had a significantly greater soil pore volume-fraction at the root-soil interface. Effects of pore structure on diffusion and permeability were estimated to be functionally insignificant under saturated conditions when simulated using image-based modelling. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

Analysis of turbulence and surface growth models on the estimation of soot level in ethylene non-premixed flames

NASA Astrophysics Data System (ADS)

Yunardi, Y.; Munawar, Edi; Rinaldi, Wahyu; Razali, Asbar; Iskandar, Elwina; Fairweather, M.

2018-02-01

Soot prediction in a combustion system has become a subject of attention, as many factors influence its accuracy. An accurate temperature prediction will likely yield better soot predictions, since the inception, growth and destruction of the soot are affected by the temperature. This paper reported the study on the influences of turbulence closure and surface growth models on the prediction of soot levels in turbulent flames. The results demonstrated that a substantial distinction was observed in terms of temperature predictions derived using the k-ɛ and the Reynolds stress models, for the two ethylene flames studied here amongst the four types of surface growth rate model investigated, the assumption of the soot surface growth rate proportional to the particle number density, but independent on the surface area of soot particles, f ( A s ) = ρ N s , yields in closest agreement with the radial data. Without any adjustment to the constants in the surface growth term, other approaches where the surface growth directly proportional to the surface area and square root of surface area, f ( A s ) = A s and f ( A s ) = √ A s , result in an under- prediction of soot volume fraction. These results suggest that predictions of soot volume fraction are sensitive to the modelling of surface growth.

Uptake of PAHs by cabbage root and leaf in vegetable plots near a large coking manufacturer and associations with PAHs in cabbage core.

PubMed

Xiong, GuanNan; Zhang, YunHui; Duan, YongHong; Cai, ChuanYang; Wang, Xin; Li, JingYa; Tao, Shu; Liu, WenXin

2017-08-01

Samples of ambient air (including gaseous and particulate phases), dust fall, surface soil, rhizosphere soil, core (edible part), outer leaf, and root of cabbage from eight vegetable plots near a large coking manufacturer were collected during the harvest period. Concentrations, compositions, and distributions of parent PAHs in different samples were determined. Our results indicated that most of the parent PAHs in air occurred in the gaseous phase, dominated by low molecular weight (LMW) species with two to three rings. Specific isomeric ratios and principal component analysis were employed to preliminarily identify the local sources of parent PAHs emitted. The main emission sources of parent PAHs could be apportioned as a mixture of coal combustion, coking production, and traffic tailing gas. PAH components with two to four rings were prevailing in dust fall, surface soil, and rhizosphere soil. Concentrations of PAHs in surface soil exhibited a significant positive correlation with topsoil TOC fractions. Compositional profiles in outer leaf and core of cabbage, dominated by LMW species, were similar to those in the local air. Overall, the order of parent PAH concentration in cabbage was outer leaf > root > core. Partial correlation analysis and multivariate linear stepwise regression revealed that PAH concentrations in cabbage core were closely associated with PAHs present both in root and in outer leaf, namely, affected by adsorption, then absorption, and translocation of PAHs from rhizosphere soil and ambient air, respectively.

Water dynamics in different biochar fractions.

PubMed

Conte, Pellegrino; Nestle, Nikolaus

2015-09-01

Biochar is a carbonaceous porous material deliberately applied to soil to improve its fertility. The mechanisms through which biochar acts on fertility are still poorly understood. The effect of biochar texture size on water dynamics was investigated here in order to provide information to address future research on nutrient mobility towards plant roots as biochar is applied as soil amendment. A poplar biochar has been stainless steel fractionated in three different textured fractions (1.0-2.0 mm, 0.3-1.0 mm and <0.3 mm, respectively). Water-saturated fractions were analyzed by fast field cycling (FFC) NMR relaxometry. Results proved that 3D exchange between bound and bulk water predominantly occurred in the coarsest fraction. However, as porosity decreased, water motion was mainly associated to a restricted 2D diffusion among the surface-site pores and the bulk-site ones. The X-ray μ-CT imaging analyses on the dry fractions revealed the lowest surface/volume ratio for the coarsest fraction, thereby corroborating the 3D water exchange mechanism hypothesized by FFC NMR relaxometry. However, multi-micrometer porosity was evidenced in all the samples. The latter finding suggested that the 3D exchange mechanism cannot even be neglected in the finest fraction as previously excluded only on the basis of NMR relaxometry results. X-ray μ-CT imaging showed heterogeneous distribution of inorganic materials inside all the fractions. The mineral components may contribute to the water relaxation mechanisms by FFC NMR relaxometry. Further studies are needed to understand the role of the inorganic particles on water dynamics. Copyright © 2015 John Wiley & Sons, Ltd.

Long-term effects of elevated atmospheric CO{sub 2} on below-ground biomass and transformations to soil organic matter in grassland.

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

Jastrow, J.D.; Miller, R.M.; Owensby, C.E.

2000-01-01

We determined the effects of elevated [CO{sub 2}] on the quantity and quality of below-ground biomass and several soil organic matter pools at the conclusion of an eight-year CO{sub 2} enrichment experiment on native tallgrass prairie. Plots in open-top chambers were exposed continuously to ambient and twice-ambient [CO{sub 2}] from early April through late October of each year. Soil was sampled to a depth of 30 cm beneath and next to the crowns of C4 grasses in these plots and in unchambered plots. Elevated [CO{sub 2}] increased the standing crops of rhizomes (87%), coarse roots (46%), and fibrous roots (40%)more » but had no effect on root litter (mostly fine root fragments and sloughed cortex material >500 {mu}m). Soil C and N stocks also increased under elevated [CO{sub 2}], with accumulations in the silt/clay fraction over twice that of particulate organic matter (POM; >53 {mu}m). The mostly root-like, light POM (density {<=}1.8 Mg m{sup -3}) appeared to turn over more rapidly, while the more amorphous and rendered heavy POM (density >1.8 Mg m{sup -3}) accumulated under elevated [CO{sub 2}]. Overall, rhizome and root C:N ratios were not greatly affected by CO{sub 2} enrichment. However, elevated [CO{sub 2}] increased the C:N ratios of root litter and POM in the surface 5 cm and induced a small but significant increase in the C:N ratio of the silt/clay fraction to a depth of 15 cm. Our data suggest that 8 years of CO{sub 2} enrichment may have affected elements of the N cycle (including mineralization, immobilization, and asymbiotic fixation) but that any changes in N dynamics were insufficient to prevent significant plant growth responses.« less

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

Filley, T. R.; Boutton, T. W.; Liao, J. D.

Encroachment of thorn woodlands into grasslands of southern Texas has resulted in greater aboveground and belowground biomass and greater soil organic carbon (SOC) stocks. Our previous studies showed that a large percentage of the SOC accrued under invading woody clusters was not stabilized within protective soil aggregates or on mineral-surfaces. Here we evaluated lignin and cutin- and suberin-derived substituted fatty acid (SFA) chemistry to determine if the accrual of nonaggregated particulate organic matter (POM) in woodlands was promoted by inherently greater recalcitrance of tissues from woody versus grass species, and if there was selective input of aboveground versus belowground plantmore » carbon to POM. Woody clusters exhibited reduced concentrations of cutin-derived SFA and cinnamyl phenols within surface litter compared to fresh aboveground plant material. However, root litter exhibited relatively minor changes in biopolymer chemistry compared to fresh root tissue, suggesting it was either more stable or was refreshed at a greater rate. Between 14 and 105 years of woody plant encroachment, SFA in free POM fractions appeared to be consistently derived from root material while SFA within intraaggregate POM were increasingly derived from cutin sources. In addition, the shift from herbaceous to woody input was accompanied by enrichment in the amount of cutin and suberin-derived aliphatics with respect to lignin in both root and surface litter as well as nonaggregated POM. Woody plant encroachment at this site results in the rapid accrual of POM pools that are biochemically recalcitrant, providing a mechanism by which soil organic carbon can accumulate in this sandy soil system. Our results also lend further credence to the hypothesis that aliphatic biopolymers, particularly root-derived suberin, are important components of long-term soil organic carbon stabilization.« less

Chemical changes to nonaggregated particulate soil organic matter following grassland-to-woodland transition in a subtropical savanna

NASA Astrophysics Data System (ADS)

Filley, Timothy R.; Boutton, Thomas W.; Liao, Julia D.; Jastrow, Julie D.; Gamblin, David E.

2008-09-01

Encroachment of thorn woodlands into grasslands of southern Texas has resulted in greater aboveground and belowground biomass and greater soil organic carbon (SOC) stocks. Our previous studies showed that a large percentage of the SOC accrued under invading woody clusters was not stabilized within protective soil aggregates or on mineral-surfaces. Here we evaluated lignin and cutin- and suberin-derived substituted fatty acid (SFA) chemistry to determine if the accrual of nonaggregated particulate organic matter (POM) in woodlands was promoted by inherently greater recalcitrance of tissues from woody versus grass species, and if there was selective input of aboveground versus belowground plant carbon to POM. Woody clusters exhibited reduced concentrations of cutin-derived SFA and cinnamyl phenols within surface litter compared to fresh aboveground plant material. However, root litter exhibited relatively minor changes in biopolymer chemistry compared to fresh root tissue, suggesting it was either more stable or was refreshed at a greater rate. Between 14 and 105 years of woody plant encroachment, SFA in free POM fractions appeared to be consistently derived from root material while SFA within intraaggregate POM were increasingly derived from cutin sources. In addition, the shift from herbaceous to woody input was accompanied by enrichment in the amount of cutin and suberin-derived aliphatics with respect to lignin in both root and surface litter as well as nonaggregated POM. Woody plant encroachment at this site results in the rapid accrual of POM pools that are biochemically recalcitrant, providing a mechanism by which soil organic carbon can accumulate in this sandy soil system. Our results also lend further credence to the hypothesis that aliphatic biopolymers, particularly root-derived suberin, are important components of long-term soil organic carbon stabilization.

A discrete model of Ostwald ripening based on multiple pairwise interactions

NASA Astrophysics Data System (ADS)

Di Nunzio, Paolo Emilio

2018-06-01

A discrete multi-particle model of Ostwald ripening based on direct pairwise interactions is developed for particles with incoherent interfaces as an alternative to the classical LSW mean field theory. The rate of matter exchange depends on the average surface-to-surface interparticle distance, a characteristic feature of the system which naturally incorporates the effect of volume fraction of second phase. The multi-particle diffusion is described through the definition of an interaction volume containing all the particles involved in the exchange of solute. At small volume fractions this is proportional to the size of the central particle, at higher volume fractions it gradually reduces as a consequence of diffusion screening described on a geometrical basis. The topological noise present in real systems is also included. For volume fractions below about 0.1 the model predicts broad and right-skewed stationary size distributions resembling a lognormal function. Above this value, a transition to sharper, more symmetrical but still right-skewed shapes occurs. An excellent agreement with experiments is obtained for 3D particle size distributions of solid-solid and solid-liquid systems with volume fraction 0.07, 0.30, 0.52 and 0.74. The kinetic constant of the model depends on the cube root of volume fraction up to about 0.1, then increases rapidly with an upward concavity. It is in good agreement with the available literature data on solid-liquid mixtures in the volume fraction range from 0.20 to about 0.75.

Anti-angiogenic activity of Entada africana root.

PubMed

Germanò, Maria Paola; Certo, Giovanna; D'Angelo, Valeria; Sanogo, Rokia; Malafronte, Nicola; De Tommasi, Nunziatina; Rapisarda, Antonio

2015-01-01

Entada africana roots are used in African traditional medicine for various diseases including inflammation. This application may be mediated through anti-angiogenic effects. Thus, in this study the anti-angiogenic activity of E. africana root extracts (n-hexane, chloroform, chloroform/methanol and methanol) was preliminarily evaluated by the quantitative determination of endogenous alkaline phosphatase in zebrafish embryos. A bioactivity-guided fractionation of chloroform/methanol extract yielded apigenin and robinetin as the main constituents from the most active fractions. In addition, a marked reduction on capillary formation was evidenced in chick chorioallantoic membrane after treatment with the active fractions or isolated compounds. Results obtained in this study suggest that the anti-angiogenic effects of E. africana root may account for its use in inflammatory diseases and other related pathological conditions.

Fractionations of rare earth elements in plants and their conceptive model.

PubMed

Ding, ShiMing; Liang, Tao; Yan, JunCai; Zhang, ZiLi; Huang, ZeChun; Xie, YaNing

2007-02-01

Fractionations of rare earth elements (REEs) and their mechanisms in soybean were studied through application of exogenous mixed REEs under hydroponic conditions. Significant enrichment of middle REEs (MREEs) and heavy REEs (HREEs) was observed in plant roots and leaves respectively, with slight fractionation between light REEs (LREEs) and HREEs in stems. Moreover, the tetrad effect was observed in these organs. Investigations into REE speciation in roots and in the xylem sap using X-ray absorption spectroscopy (XAS) and nanometer-sized TiO2 adsorption techniques, associated with other controlled experiments, demonstrated that REE fractionations should be dominated by fixation mechanism in roots caused by cell wall absorption and phosphate precipitation, and by the combined effects of fixation mechanism and transport mechanism in aboveground parts caused by solution complexation by intrinsic organic ligands. A conceptive model was established for REE fractionations in plants based on the above studies.

Impacts of leaves, roots, and earthworms on soil organic matter composition and distribution in sycamore maple stands

NASA Astrophysics Data System (ADS)

Rivera, N.; Mueller, K. E.; Mueller, C. W.; Oleksyn, J.; Hale, C.; Freeman, K. H.; Eissenstat, D.

2009-12-01

The relative contributions of leaf and root material to soil organic matter (SOM) are poorly understood despite the importance of constraining SOM sources to conceptual and numeric models of SOM dynamics. Selective ingestion and bioturbation of litter and soil by earthworms can alter the fate and spatial distribution of OM in soils, including stabilization pathways of leaf and root litter. However, studies on the contributions of leaves, roots, and earthworms to SOM dynamics are rare. In 3 stands of sycamore maple (Acer pseudoplatanus) with minimal O horizon development and high earthworm activity, we sampled surface litter (> 2 mm) from the Oi horizon, fine roots (< 2 mm), bulk mineral soils (0-20 cm depth), and earthworm casts from Lumbricus terrestris middens. The chemical composition of these samples was estimated by wet-chemical degradation followed by GC-MS analysis. In addition, elemental analyses (C and N) were performed on bulk soils and earthworm casts, before and after physical fractionation by means of particle size and density. Relative to bulk soils, earthworm casts were highly enriched in organic matter, dominated by large particulate OM, and had lower acid to aldehyde ratios among lignin monomers (a proxy for extent of decomposition), confirming that L. terrestris casts stabilize recent plant litter inputs. Maple fine roots and surface litter were distinguished by different profiles of carboxylic acids estimated by GC-MS, facilitating interpretation of OM sources in bulk soil and earthworm casts. Earthworm casts were characterized by a distribution of carboxylic acids similar to that of surface litter while bulk soils had a carboxylic acid profile much closer to that of roots. These results confirm that L. terrestris is primarily a surface, leaf feeder and suggest that OM in the bulk soil may be dominated by root inputs. In bulk soils, the ratio of lignin to hydroxy- and diacids derived from suberin and cutin was low relative to plant litter, confirming the often-observed selective preservation of aliphatic over aromatic biomolecules. The ratio of lignin to cutin/suberin acids in earthworm casts was also low; based on the minimal extent of decomposition in casts evident by lignin acid to aldehyde ratios, we attribute this to selective ingestion by L. terrestris of leaf litter rich in aliphatic biomolecules at the expense of woody debris and petioles rich in lignin, rather than selective preservation.

Comprehensive assessment of phenolics and antiradical potential of Rumex hastatus D. Don. roots

PubMed Central

2014-01-01

Background Roots of Rumex hastatus (Polygonaceae) are traditionally used for the treatment of various ailments including liver and lung diseases. In this study, various solvent extracts of R. hastatus roots, like methanolic, n-hexane, ethyl acetate, chloroform, butanol and aqueous fractions were assessed through their antioxidant properties in vitro and determination of phenolic contents. Methods Several parameters like DPPH˙, ABTS˙+, ˙OH, H2O2, superoxide free radical scavenging, iron chelating power, reducing power, β-carotene bleaching power, antioxidant capacity and total phenolics and flavonoids were evaluated. High Performance liquid Chromatography (HPLC) was also considered. Results Though all the fractions exhibited dose dependant activity. The samples with the highest activity were the butanol and methanol fractions in all the assays except hydrogen peroxide radical scavenging assay where chloroform fraction showed the highest scavenging aptitude. On the other hand, aquous fraction showed significant beta carotene linoleic acid, while n-hexane and ethyl acetate fractions exhibited a lesser antioxidant activity in all the assays. HPLC revealed the presence of rutin, luteolin-7-glucoside, vitexin and luteolin. Conclusion These results have to some extent substantiated the use of R. hastatus roots against different diseases, as an excellent basis of potential antioxidant due to the presence of sufficient amount of phenolics such as rutin and luteolin. PMID:24507200

Comprehensive assessment of phenolics and antiradical potential of Rumex hastatus D. Don. roots.

PubMed

Sahreen, Sumaira; Khan, Muhammad Rashid; Khan, Rahmat Ali

2014-02-08

Roots of Rumex hastatus (Polygonaceae) are traditionally used for the treatment of various ailments including liver and lung diseases. In this study, various solvent extracts of R. hastatus roots, like methanolic, n-hexane, ethyl acetate, chloroform, butanol and aqueous fractions were assessed through their antioxidant properties in vitro and determination of phenolic contents. Several parameters like DPPH˙, ABTS˙(+), ˙OH, H2O2, superoxide free radical scavenging, iron chelating power, reducing power, β-carotene bleaching power, antioxidant capacity and total phenolics and flavonoids were evaluated. High Performance liquid Chromatography (HPLC) was also considered. Though all the fractions exhibited dose dependant activity. The samples with the highest activity were the butanol and methanol fractions in all the assays except hydrogen peroxide radical scavenging assay where chloroform fraction showed the highest scavenging aptitude. On the other hand, aquous fraction showed significant beta carotene linoleic acid, while n-hexane and ethyl acetate fractions exhibited a lesser antioxidant activity in all the assays. HPLC revealed the presence of rutin, luteolin-7-glucoside, vitexin and luteolin. These results have to some extent substantiated the use of R. hastatus roots against different diseases, as an excellent basis of potential antioxidant due to the presence of sufficient amount of phenolics such as rutin and luteolin.

Effectiveness of DIAGNOdent in Detecting Root Caries Without Dental Scaling Among Community-dwelling Elderly.

PubMed

Zhang, Wen; McGrath, Colman; Lo, Edward C M

The purpose of this clinical research was to analyze the effectiveness of DIAGNOdent in detecting root caries without dental scaling. The status of 750 exposed, unfilled root surfaces was assessed by visual-tactile examination and DIAGNOdent before and after root scaling. The sensitivity and specificity of different cut-off DIAGNOdent values in diagnosing root caries with reference to visual-tactile criteria were evaluated on those root surfaces without visible plaque/calculus. The DIAGNOdent values from sound and carious root surfaces were compared using the nonparametric Mann-Whitney U-test. The level of statistical significance was set at 0.05. On root surfaces without plaque/calculus, significantly different (p < 0.05) DIAGNOdent readings were obtained from sound root surfaces (12.2 ± 11.1), active carious root surfaces (37.6 ± 31.7) and inactive carious root surfaces (20.9 ± 10.5) before scaling. On root surfaces with visible plaque, DIAGNOdent readings obtained from active carious root surfaces (29.6 ± 20.8) and inactive carious root surfaces (27.0 ± 7.2) were not statistically significantly different (p > 0.05). Furthermore, on root surfaces with visible calculus, all DIAGNOdent readings obtained from sound root surfaces were > 50, which might be misinterpreted as carious. After scaling, the DIAGNOdent readings obtained from sound root surfaces (8.1 ± 11.3), active carious root surfaces (37.9 ± 31.9) and inactive carious root surfaces (24.9 ± 11.5) presented significant differences (p < 0.05). A cut-off value between 10 and 15 yielded the highest combined sensitivity and specificity in detecting root caries on root surfaces without visible plaque/calculus before scaling, but the combined sensitivity and specificity are both around 70%. These findings suggest that on exposed, unfilled root surfaces without visible plaque/calculus, DIAGNOdent can be used as an adjunct to the visual-tactile criteria in detecting root-surface status without pre-treatment by dental scaling.

Allometric growth and allocation in forests: a perspective from FLUXNET.

PubMed

Wolf, Adam; Field, Christopher B; Berry, Joseph A

2011-07-01

To develop a scheme for partitioning the products of photosynthesis toward different biomass components in land-surface models, a database on component mass and net primary productivity (NPP), collected from FLUXNET sites, was examined to determine allometric patterns of allocation. We found that NPP per individual of foliage (Gfol), stem and branches (Gstem), coarse roots (Gcroot) and fine roots (Gfroot) in individual trees is largely explained (r2 = 67-91%) by the magnitude of total NPP per individual (G). Gfol scales with G isometrically, meaning it is a fixed fraction of G ( 25%). Root-shoot trade-offs were manifest as a slow decline in Gfroot, as a fraction of G, from 50% to 25% as stands increased in biomass, with Gstem and Gcroot increasing as a consequence. These results indicate that a functional trade-off between aboveground and belowground allocation is essentially captured by variations in G, which itself is largely governed by stand biomass and only secondarily by site-specific resource availability. We argue that forests are characterized by strong competition for light, observed as a race for individual trees to ascend by increasing partitioning toward wood, rather than by growing more leaves, and that this competition stronglyconstrains the allocational plasticity that trees may be capable of. The residual variation in partitioning was not related to climatic or edaphic factors, nor did plots with nutrient or water additions show a pattern of partitioning distinct from that predicted by G alone. These findings leverage short-term process studies of the terrestrial carbon cycle to improve decade-scale predictions of biomass accumulation in forests. An algorithm for calculating partitioning in land-surface models is presented.

Amount of cadmium associated with Cd-binding protein in roots of young plants. [Agrostis gigantea

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

Rauser, W.E.

1986-04-01

The partitioning of Cd between roots and shoots was determined for young plants exposed to Cd in nutrient solution. The intentionally high concentration of 3 ..mu..m Cd was used to assess the role of root Cd-binding protein (Cd-BP) in Cd detoxification. The roots of tomatoes exposed to Cd retained 60-84% of the plant Cd from day 2 through day 9 without toxicity symptoms evident. Cd-BP did not contribute to Cd retention over the initial 4 days, only 1-4% of the root Cd was in this protein fraction. Maize roots retained 59-66% of the plant Cd from day 1 through daymore » 7. The Cd-BP fraction bound 8-19% of the root Cd on day 1 and 31-55% by day 7. Cd toxicity symptoms occurred in leaves by 4 days. In the grass Agrostis gigantea the roots retained 73-85% of the seedling Cd after 1 day and for another 6 days. A high proportion of the root Cd(34-68%) was in the Cd-BP fraction after one day and continued to be so to day 7 (46-64%). No Cd toxicity symptoms were evident. Only the specific pattern of rapid, early and sustained production of Cd-BP observed in Agrostis was consistent with the putative detoxification role for Cd-BP.« less

M-Mode Echocardiographic Changes in Growing Beagles

PubMed Central

Diez-Prieto, Inmaculada; García-Rodríguez, M Belén; Ríos-Granja, M Angeles; Cano-Rábano, María J; Peña-Penabad, Marina; Pérez-García, Carlos C

2010-01-01

Heart growth in 6 female beagle dogs was measured by using M-mode echocardiography at 4, 7, 10, 13, 17, and 21 mo of age. The same 6 dogs were evaluated throughout the study to establish when cardiac development ends in this breed. The following parameters were measured during systole and diastole: left ventricle posterior wall thickness, interventricular septal thickness, left ventricular internal dimension, left atrial dimension during ventricular systole, aortic root dimension at end diastole, E-point to septal separation, left ventricular preejection period, ejection time of the left ventricular outflow, and time between the cessation and onset of the mitral inflow intervals. The percentage of the left ventricle posterior wall thickening, fractional shortening, ejection fraction, left ventricular end systolic and end-diastolic volumes, ratio of the left atrial dimension to aortic root dimension, and the Tei index of myocardial performance were calculated. The heart rate was measured by cardiac auscultation. The influence of ageing on each echocardiographic parameter and relationships with body weight and surface were studied. Results show that cardiac development in female beagles can be considered finished by the age of 1 y, perhaps as soon as 7 mo. The cardiac indexes studied were unaffected by the age and corporal dimensions, confirming the usefulness of these parameters for evaluating cardiac functionality alterations independent of a dog's age and body weight or surface area. PMID:20122313

How does litter become soil organic matter? Tracing the fate of needle- and root-derived soil organic matter through 10 years of decomposition

NASA Astrophysics Data System (ADS)

Hicks Pries, Caitlin E.; Hatton, Pierre-Joseph; Castanha, Cristina; Bird, Jeffrey A.; Torn, Margaret S.

2014-05-01

All soil organic matter (SOM) is derived from plant material. However, little is known about the process by which plant litter becomes SOM (as opposed to the better-studied controls on rates of carbon (C) and nitrogen (N) loss from litter). We investigated the transformations of above- and below-ground plant inputs in soil over ten years, and whether litter type (roots versus needles) affects the form and location of litter-derived C and N in soil after 10 years. We placed 15N and 13C-labeled Pinus ponderosa needle and fine root litter in the Blodgett Experimental Forest in the Sierra Nevada foothills in 2001. A two-way factorial design was used with needle and root litter placed into O and A soil horizons. Litter was inserted into the given horizon within soil mesocosms (10.2 cm diameter x 24 cm long PVC) that had two 5 x 5 cm mesh windows to allow contact with the surrounding soil. After 0.5, 1, 1.5, 4.5, and 10 years, the mesocosms were collected from the field. Isotopes were used to measure the percent recovery of the litter C and N in the bulk soil of the O and A horizons. To investigate mineral associations of the added litter C and N after 10 years, we sequentially fractionated the soils by density. The fractions were a free light fraction (<1.75 g cm-3), a fraction dominated by secondary phyllosilicate minerals (1.75-2.5 g cm-3), a quartz and feldspar-dominated fraction (2.5-2.78 g cm-3), and a fraction dominated by biotite with kaolinite and iron oxide coatings (>2.78 g cm-3). These fractions differ in the type of organic matter they are associated with according to C:N ratios and molecular characterization via FTIR. The biotite fraction had the lowest C:N ratios, indicating it was the most microbially-processed. After 10 years, more root litter C (about 44%) was retained in the soil than needle litter C (about 28%). In line with slower rates of decomposition, root C and N remained in the particulate (>2 mm) fraction and the free light fraction longer than needle C. However, there were similar amounts of root and needle C and N in the mineral-associated pools with 12-17% of the remaining C associated with secondary phyllosilicates and less than 1% associated with biotite. C:N ratios of the litter-derived OM were much lower in the mineral fractions than in the free light fraction. In conclusion, litter type affects how long organic matter is retained in soils by affecting the earlier stages of decomposition when microbes are utilizing substrates that are part of larger OM particles, but litter type does not appear to affect later stages of decomposition, when microbially-processed OM becomes associated with minerals.

A brief description of the simple biosphere model (SiB)

NASA Technical Reports Server (NTRS)

Sellers, P. J.; Mintz, Y.; Sud, Y. C.

1986-01-01

A biosphere model for calculating the transfer of energy, mass, and momentum between the atmosphere and the vegetated surface of the Earth was designed for atmospheric general circulation models. An upper vegetation layer represents the perennial canopy of trees or shrubs, a lower layer represents the annual ground cover of grasses and other herbacious species. The local coverage of each vegetation layer may be fractional or complete but as the individual vegetation elements are considered to be evenly spaced, their root systems are assumed to extend uniformly throughout the entire grid-area. The biosphere has seven prognostic physical-state variables: two temperatures (one for the canopy and one for the ground cover and soil surface); two interception water stores (one for the canopy and one for the ground cover); and three soil moisture stores (two of which can be reached by the vegetation root systems and one underlying recharge layer into and out of which moisture is transferred only by hydraulic diffusion).

Long-distance abscisic acid signalling under different vertical soil moisture gradients depends on bulk root water potential and average soil water content in the root zone.

PubMed

Puértolas, Jaime; Alcobendas, Rosalía; Alarcón, Juan J; Dodd, Ian C

2013-08-01

To determine how root-to-shoot abscisic acid (ABA) signalling is regulated by vertical soil moisture gradients, root ABA concentration ([ABA](root)), the fraction of root water uptake from, and root water potential of different parts of the root zone, along with bulk root water potential, were measured to test various predictive models of root xylem ABA concentration [RX-ABA](sap). Beans (Phaseolus vulgaris L. cv. Nassau) were grown in soil columns and received different irrigation treatments (top and basal watering, and withholding water for varying lengths of time) to induce different vertical soil moisture gradients. Root water uptake was measured at four positions within the column by continuously recording volumetric soil water content (θv). Average θv was inversely related to bulk root water potential (Ψ(root)). In turn, Ψ(root) was correlated with both average [ABA](root) and [RX-ABA](sap). Despite large gradients in θv, [ABA](root) and root water potential was homogenous within the root zone. Consequently, unlike some split-root studies, root water uptake fraction from layers with different soil moisture did not influence xylem sap (ABA). This suggests two different patterns of ABA signalling, depending on how soil moisture heterogeneity is distributed within the root zone, which might have implications for implementing water-saving irrigation techniques. © 2013 John Wiley & Sons Ltd.

Characterization of Cadmium Uptake by Plant Tissue 12

PubMed Central

Cutler, Jay M.; Rains, Donald W.

1974-01-01

The uptake of cadmium by excised root tissue of barley (Hordeum vulgare L. cv. Arivat) was investigated with respect to kinetics, concentration, and interactions with various cations. The role of metabolism in Cd absorption was examined using a range of temperatures, anaerobic treatments, and chemical inhibitors. The uptake and distribution of Cd in intact barley plants was also determined. A large fraction of the Cd taken up by excised barley roots was apparently the result of exchange adsorption and was displaced by subsequent desorption with unlabeled Cd, Zn, Cu, or Hg. Another fraction of Cd which could not be displaced by desorption in unlabeled Cd was thought to result from strong irreversible binding of Cd, perhaps on sites of the cell wall. The fraction of the Cd taken up beyond that by exchange adsorption by fresh roots was a linear function of temperature, and inhibited by conditions of low oxygen and by the presence of 2,4-dinitrophenol. It was concluded that this fraction of Cd entered excised barley roots by diffusion. Diffusion, when followed by sequestering, probably accounts for the accumulation of Cd observed in intact barley plants. PMID:16658840

Structure-Property-Function Relationship in Humic Substances to Explain the Biological Activity in Plants

PubMed Central

García, Andrés Calderín; de Souza, Luiz Gilberto Ambrosio; Pereira, Marcos Gervasio; Castro, Rosane Nora; García-Mina, José María; Zonta, Everaldo; Lisboa, Francy Junior Gonçalves; Berbara, Ricardo Luis Louro

2016-01-01

Knowledge of the structure-property-function relationship of humic substances (HSs) is key for understanding their role in soil. Despite progress, studies on this topic are still under discussion. We analyzed 37 humic fractions with respect to their isotopic composition, structural characteristics, and properties responsible for stimulating plant root parameters. We showed that regardless of the source of origin of the carbon (C3 or C4), soil-extracted HSs and humic acids (HAs) are structurally similar to each other. The more labile and functionalized HS fraction is responsible for root emission, whereas the more recalcitrant and less functionalized HA fraction is related to root growth. Labile structures promote root stimulation at lower concentrations, while recalcitrant structures require higher concentrations to promote a similar stimulus. These findings show that lability and recalcitrance, which are derived properties of humic fractions, are related to the type and intensity of their bioactivity. In summary, the comparison of humic fractions allowed a better understanding of the relationship between the source of origin of plant carbon and the structure, properties, and type and intensity of the bioactivity of HSs in plants. In this study, scientific concepts are unified and the basis for the agronomic use of HSs is established. PMID:26862010

Nickel and zinc isotope fractionation in hyperaccumulating and nonaccumulating plants.

PubMed

Deng, Teng-Hao-Bo; Cloquet, Christophe; Tang, Ye-Tao; Sterckeman, Thibault; Echevarria, Guillaume; Estrade, Nicolas; Morel, Jean-Louis; Qiu, Rong-Liang

2014-10-21

Until now, there has been little data on the isotope fractionation of nickel (Ni) in higher plants and how this can be affected by plant Ni and zinc (Zn) homeostasis. A hydroponic cultivation was conducted to investigate the isotope fractionation of Ni and Zn during plant uptake and translocation processes. The nonaccumulator Thlaspi arvense, the Ni hyperaccumulator Alyssum murale and the Ni and Zn hyperaccumulator Noccaea caerulescens were grown in low (2 μM) and high (50 μM) Ni and Zn solutions. Results showed that plants were inclined to absorb light Ni isotopes, presumably due to the functioning of low-affinity transport systems across root cell membrane. The Ni isotope fractionation between plant and solution was greater in the hyperaccumulators grown in low Zn treatments (Δ(60)Ni(plant-solution) = -0.90 to -0.63‰) than that in the nonaccumulator T. arvense (Δ(60)Ni(plant-solution) = -0.21‰), thus indicating a greater permeability of the low-affinity transport system in hyperaccumulators. Light isotope enrichment of Zn was observed in most of the plants (Δ(66)Zn(plant-solution) = -0.23 to -0.10‰), but to a lesser extent than for Ni. The rapid uptake of Zn on the root surfaces caused concentration gradients, which induced ion diffusion in the rhizosphere and could result in light Zn isotope enrichment in the hyperaccumulator N. caerulescens. In high Zn treatment, Zn could compete with Ni during the uptake process, which reduced Ni concentration in plants and decreased the extent of Ni isotope fractionation (Δ(60)Ni(plant-solution) = -0.11 to -0.07‰), indicating that plants might take up Ni through a low-affinity transport system of Zn. We propose that isotope composition analysis for transition elements could become an empirical tool to study plant physiological processes.

Cadmium chemical speciation and absorption in plant in a polluted soil

NASA Astrophysics Data System (ADS)

Gigliotti, Giovanni; Massaccesi, Luisa

2013-04-01

Cadmium is a very toxic heavy metal presents in nature in small amounts, with an average content of 0.2 mg kg-1 in the geosphere. Nonetheless, anthropogenic activities such as industrial processes, large use of phosphate fertilizers and sewage sludge disposals may determine a massive accumulation of Cd in soil. Cd is considered a particularly interesting heavy metal as it can be accumulated by plants to levels that can be toxic to humans and animals, when consumed even in minor amounts. The aim of the present work was to study in a soil polluted with Cd for a long time i) the distribution of Cd in different chemical fractions by means of a sequential extraction procedure; ii) the adsorption of Cd by plants grown in this polluted soil; iii) the change in the distribution of Cd in the soil fractions possibly due to root exudates after plant growing. The chemical fractionation procedure used involved the following forms: a) exchangeable, b) bound to carbonates, c) bound to Fe-Mn oxides and hydroxides, d) bound to organic matter, e) residual part. The following reagents and extraction times were applied: a) 1 M CH3COONa (1:10, w/v; pH 8.2) for 16 h at room temperature; b) 0,1 M CH3COOH for 16 h at room temperature; c) 0,1 M NH2OH•HCl (1:10, w/v; adjusted to pH 2.0 with HNO3) for 16 h at room temperature; d) 30% H2O2 (adjusted to pH 2.0 with HNO3) at 85 °C, followed by extraction with 1 M CH3COONH4 (1:10, w/v; adjusted to pH 2.0 with HNO3) for 16 h at room temperature; e) acid digestion with concentrated HNO3 and 30% H2O2 for residue fraction. Festuca seeds were germinated in the contaminated soil in plastic flats and non-contaminated soil. After two days the seedling were submitted to day/night conditions. The seedlings were collected 6 weeks after seeding and divided in roots and shoots and analysed for Cd concentration. The polluted soil has average Cd content of 200 mg kg-1, instead, the Cd content in the same unpolluted soil was about 0.44 mg kg-1. The speciation results showed that a significant amount of Cd (45%), before plant seeding, was associated with the metal oxide fraction (typically Fe-Mn oxides and hydroxides) followed to Cd bound to soil organic matter (39%), despite the content of organic matter in the soil was very low. Instead the amount of Cd bound to carbonates (13%), exchangeable phase (1%) and residue fraction (2.5%) were negligible. After six weeks of plant seeding the Cd fractionation was slightly different, with a decrease of metal bound to oxide and hydroxide from 45% to 29% and an increase of fraction bound to carbonate from 13% to 19% and exchangeable fraction from 1% to 8%. The roots system of Festuca had colonized all pot and the fractionation of metal was disturbed by plants growth. Roots may induce changes in the biochemical, chemical and physical properties of the rhizosphere increasing potentially toxic elements diffusion through the production of roots exudates. The soil environment immediately adjacent to the root can be strongly influenced by root exudates, so that chemical process of dissolution, chelation and precipitation outside the root also occur. Cd was absorbed by plant root in a great concentration, but not translocation to leafs was noticed.

Aluminum fractions in root tips of slash pine and loblolly pine families differing in Al resistance

Treesearch

Jaroslaw Nowak; Alexander L. Friend

2005-01-01

Aluminum (Al) distribution among several cellular fractions was investigated in root tips of seedlings of one Al-resistant and one Al-sensitive family of slash pine (Pinus elliottii Engelm.) and loblolly pine (Pinus taeda L.) grown in nutrient solution containing 100 M AlCl3 (pH 4) for 167 h....

On the scaling of the slip velocity in turbulent flows over superhydrophobic surfaces

NASA Astrophysics Data System (ADS)

Seo, Jongmin; Mani, Ali

2016-02-01

Superhydrophobic surfaces can significantly reduce hydrodynamic skin drag by accommodating large slip velocity near the surface due to entrapment of air bubbles within their micro-scale roughness elements. While there are many Stokes flow solutions for flows near superhydrophobic surfaces that describe the relation between effective slip length and surface geometry, such relations are not fully known in the turbulent flow limit. In this work, we present a phenomenological model for the kinematics of flow near a superhydrophobic surface with periodic post-patterns at high Reynolds numbers. The model predicts an inverse square root scaling with solid fraction, and a cube root scaling of the slip length with pattern size, which is different from the reported scaling in the Stokes flow limit. A mixed model is then proposed that recovers both Stokes flow solution and the presented scaling, respectively, in the small and large texture size limits. This model is validated using direct numerical simulations of turbulent flows over superhydrophobic posts over a wide range of texture sizes from L+ ≈ 6 to 310 and solid fractions from ϕs = 1/9 to 1/64. Our report also embarks on the extension of friction laws of turbulent wall-bounded flows to superhydrophobic surfaces. To this end, we present a review of a simplified model for the mean velocity profile, which we call the shifted-turbulent boundary layer model, and address two previous shortcomings regarding the closure and accuracy of this model. Furthermore, we address the process of homogenization of the texture effect to an effective slip length by investigating correlations between slip velocity and shear over pattern-averaged data for streamwise and spanwise directions. For L+ of up to O(10), shear stress and slip velocity are perfectly correlated and well described by a homogenized slip length consistent with Stokes flow solutions. In contrast, in the limit of large L+, the pattern-averaged shear stress and slip velocity become uncorrelated and thus the homogenized boundary condition is unable to capture the bulk behavior of the patterned surface.

Can the KTP laser change the cementum surface of healthy and diseased teeth providing an acceptable root surface for fibroblast attachment?

NASA Astrophysics Data System (ADS)

Mailhot, Jason M.; Garnick, Jerry J.

1996-04-01

The purpose of our research is to determine the effects of KTP laser on root cementum and fibroblast attachment. Initial work has been completed in testing the effect of different energy levels on root surfaces. From these studies optimal energy levels were determined. In subsequent studies the working distance and exposure time required to obtain significant fibroblast attachment to healthy cementum surfaces were investigated. Results showed that lased cemental surfaces exhibited changes in surface topography which ranged from a melted surface to an apparent slight fusion of the surface of the covering smear layer. When the optimal energy level was used, fibroblasts demonstrate attachment on the specimens, resulting in the presence of a monolayer of cells on the control surfaces as well as on the surfaces lased with this energy level. The present study investigates the treatment of pathological root surfaces and calculus with a KTP laser utilizing these optimal parameters determine previously. Thirty single rooted teeth with advanced periodontal disease and ten healthy teeth were obtained, crowns were sectioned and roots split longitudinally. Forty test specimens were assigned into 1 of 4 groups; pathologic root--not lased, pathologic root--lased, root planed root and health root planed root. Human gingival fibroblasts were seeded on specimens and cultured for 24 hours. Specimens were processed for SEM. The findings suggest that with the KTP laser using a predetermined energy level applied to pathological root surfaces, the lased surfaces provided an unacceptable surface for fibroblast attachment. However, the procedural control using healthy root planed surfaces did demonstrate fibroblast attachment.

Antioxidant and acetylcholinesterase inhibitory activities of ginger root (Zingiber officinale Roscoe) extract.

PubMed

Tung, Bui Thanh; Thu, Dang Kim; Thu, Nguyen Thi Kim; Hai, Nguyen Thanh

2017-05-04

Background Zingiber officinale Roscoe has been used in traditional medicine for the treatment of neurological disorder. This study aimed to investigate the phenolic contents, antioxidant, acetylcholinesterase enzyme (AChE) inhibitory activities of different fraction of Z. officinale root grown in Vietnam. Methods The roots of Z. officinale are extracted with ethanol 96 % and fractionated with n-hexane, ethyl acetate (EtOAc) and butanol (BuOH) solvents. These fractions evaluated the antioxidant activity by 1,1-Diphenyl -2-picrylhydrazyl (DPPH) assay and AChE inhibitory activity by Ellman's colorimetric method. Results Our data showed that the total phenolic content of EtOAc fraction was highest equivalents to 35.2±1.4 mg quercetin/g of fraction. Our data also demonstrated that EtOAc fraction had the strongest antioxidant activity with IC50 was 8.89±1.37 µg/mL and AChE inhibitory activity with an IC50 value of 22.85±2.37 μg/mL in a dose-dependent manner, followed by BuOH fraction and the n-hexane fraction is the weakest. Detailed kinetic analysis indicated that EtOAc fraction was mixed inhibition type with Ki (representing the affinity of the enzyme and inhibitor) was 30.61±1.43 µg/mL. Conclusions Our results suggest that the EtOAc fraction of Z. officinale may be a promising source of AChE inhibitors for Alzheimer's disease.

Integrating seasonal optical and thermal infrared spectra to characterize urban impervious surfaces with extreme spectral complexity: a Shanghai case study

NASA Astrophysics Data System (ADS)

Wang, Wei; Yao, Xinfeng; Ji, Minhe

2016-01-01

Despite recent rapid advancement in remote sensing technology, accurate mapping of the urban landscape in China still faces a great challenge due to unusually high spectral complexity in many big cities. Much of this complication comes from severe spectral confusion of impervious surfaces with polluted water bodies and bright bare soils. This paper proposes a two-step land cover decomposition method, which combines optical and thermal spectra from different seasons to cope with the issue of urban spectral complexity. First, a linear spectral mixture analysis was employed to generate fraction images for three preliminary endmembers (high albedo, low albedo, and vegetation). Seasonal change analysis on land surface temperature induced from thermal infrared spectra and coarse component fractions obtained from the first step was then used to reduce the confusion between impervious surfaces and nonimpervious materials. This method was tested with two-date Landsat multispectral data in Shanghai, one of China's megacities. The results showed that the method was capable of consistently estimating impervious surfaces in highly complex urban environments with an accuracy of R2 greater than 0.70 and both root mean square error and mean average error less than 0.20 for all test sites. This strategy seemed very promising for landscape mapping of complex urban areas.

Zinc isotopic fractionation in Phragmites australis in response to toxic levels of zinc

PubMed Central

Caldelas, Cristina; Dong, Shuofei; Araus, José Luis; Jakob Weiss, Dominik

2011-01-01

Stable isotope signatures of Zn have shown great promise in elucidating changes in uptake and translocation mechanisms of this metal in plants during environmental changes. Here this potential was tested by investigating the effect of high Zn concentrations on the isotopic fractionation patterns of Phragmites australis (Cav.) Trin. ex Steud. Plants were grown for 40 d in a nutritive solution containing 3.2 μM (sufficient) or 2 mM (toxic) Zn. The Zn isotopic composition of roots, rhizomes, shoots, and leaves was analysed. Stems and leaves were sampled at different heights to evaluate the effect of long-distance transport on Zn fractionation. During Zn sufficiency, roots, rhizomes, and shoots were isotopically heavy (δ66ZnJMC Lyon=0.2‰) while the youngest leaves were isotopically light (–0.5‰). During Zn excess, roots were still isotopically heavier (δ66Zn=0.5‰) and the rest of the plant was isotopically light (up to –0.5‰). The enrichment of heavy isotopes at the roots was attributed to Zn uptake mediated by transporter proteins under Zn-sufficient conditions and to chelation and compartmentation in Zn excess. The isotopically lighter Zn in shoots and leaves is consistent with long-distance root to shoot transport. The tolerance response of P. australis increased the range of Zn fractionation within the plant and with respect to the environment. PMID:21193582

The fractional Fourier transform and applications

NASA Technical Reports Server (NTRS)

Bailey, David H.; Swarztrauber, Paul N.

1991-01-01

This paper describes the 'fractional Fourier transform', which admits computation by an algorithm that has complexity proportional to the fast Fourier transform algorithm. Whereas the discrete Fourier transform (DFT) is based on integral roots of unity e exp -2(pi)i/n, the fractional Fourier transform is based on fractional roots of unity e exp -2(pi)i(alpha), where alpha is arbitrary. The fractional Fourier transform and the corresponding fast algorithm are useful for such applications as computing DFTs of sequences with prime lengths, computing DFTs of sparse sequences, analyzing sequences with noninteger periodicities, performing high-resolution trigonometric interpolation, detecting lines in noisy images, and detecting signals with linearly drifting frequencies. In many cases, the resulting algorithms are faster by arbitrarily large factors than conventional techniques.

Root distribution and potential interactions between allelopathic rice, sprangletop (Leptochloa spp.), and barnyardgrass (Echinochloa crus-galli) based on ¹³C isotope discrimination analysis.

PubMed

Gealy, David; Moldenhauer, Karen; Duke, Sara

2013-02-01

Weed-suppressive rice cultivars hold promise for improved and more economical weed management in rice. Interactions between roots of rice and weeds are thought to be modulated by the weed-suppressive activity of some rice cultivars, but these phenomena are difficult to measure and not well understood. Thus, above-ground productivity, weed suppression, and root distribution of 11 rice cultivars and two weed species were evaluated in a drill-seeded, flood-irrigated system at Stuttgart, Arkansas, USA in a two-year study. The allelopathic cultivars, PI 312777 and Taichung Native 1 (TN-1), three other weed-suppressive cultivars, three indica-derived breeding selections, and three non-suppressive commercial cultivars were evaluated in field plots infested with barnyardgrass (Echinochloa crus-galli (L.) Beauv.) or bearded sprangletop (sprangletop, Leptochloa fusca (L.) Kunth var. fascicularis (Lam.) N. Snow). The allelopathic cultivars produced more tillers and suppressed both weed species to a greater extent than did the breeding selections or the non-suppressive cultivars. (13)C isotope discrimination analysis of mixed root samples to a depth of 15 cm revealed that the allelopathic cultivars typically produced a greater fraction of their total root mass in the surface 0-5 cm of soil depth compared to the breeding selections or the non-suppressive cultivars, which tended to distribute their roots more evenly throughout the soil profile. These trends in root mass distribution were apparent at both early (pre-flood) and late-season stages in weed-free and weed-infested plots. Cultivar productivity and root distribution generally responded similarly to competition with the two weed species, but barnyardgrass reduced rice yield and root mass more than did sprangletop. These findings demonstrate for the first time that roots of the allelopathic cultivars PI 312777 and TN-1 explore the upper soil profile more thoroughly than do non-suppressive cultivars under weed-infested and weed-free conditions in flood-irrigated U.S. rice production systems. They raise the interesting prospect that root proliferation near the soil surface might enhance the weed-suppressive activity of allelochemical exudates released from roots. Plant architectural design for weed suppressive activity should take these traits into consideration along with other proven agronomic traits such as high tillering and yield.

Root development during soil genesis: effects of root-root interactions, mycorrhizae, and substrate

NASA Astrophysics Data System (ADS)

Salinas, A.; Zaharescu, D. G.

2015-12-01

A major driver of soil formation is the colonization and transformation of rock by plants and associated microbiota. In turn, substrate chemical composition can also influence the capacity for plant colonization and development. In order to better define these relationships, a mesocosm study was set up to analyze the effect mycorrhizal fungi, plant density and rock have on root development, and to determine the effect of root morphology on weathering and soil formation. We hypothesized that plant-plant and plant-fungi interactions have a stronger influence on root architecture and rock weathering than the substrate composition alone. Buffalo grass (Bouteloua dactyloides) was grown in a controlled environment in columns filled with either granular granite, schist, rhyolite or basalt. Each substrate was given two different treatments, including grass-microbes and grass-microbes-mycorrhizae and incubated for 120, 240, and 480 days. Columns were then extracted and analyzed for root morphology, fine fraction, and pore water major element content. Preliminary results showed that plants produced more biomass in rhyolite, followed by schist, basalt, and granite, indicating that substrate composition is an important driver of root development. In support of our hypothesis, mycorrhizae was a strong driver of root development by stimulating length growth, biomass production, and branching. However, average root length and branching also appeared to decrease in response to high plant density, though this trend was only present among roots with mycorrhizal fungi. Interestingly, fine fraction production was negatively correlated with average root thickness and volume. There is also slight evidence indicating that fine fraction production is more related to substrate composition than root morphology, though this data needs to be further analyzed. Our hope is that the results of this study can one day be applied to agricultural research in order to promote the production of crops on traditionally un-arable land.

Antibacterial and synergistic effects of the n-BuOH fraction of Sophora flavescens root against oral bacteria.

PubMed

Lee, Kyung-Yeol; Cha, Su-Mi; Choi, Sung-Mi; Cha, Jeong-Dan

2017-01-01

The antibacterial activity of an extract and several fractions of Sophora flavescens (S. flavescens) root alone and in combination with antibiotics against oral bacteria was investigated by checkerboard assay and time-kill assay. The minimum inhibitory concentration/minimum bactericidal concentration (MIC/MBC) values for all examined bacteria were 0.313-2.5/0.625-2.5 μg/mL for the n-BuOH fraction, 0.625-5/1.25-10 μg/mL for the EtOAc fraction, 0.25-8/0.25-16 μg/mL for ampicillin, 0.5-256/1-512 μg/mL for gentamicin, 0.008-32/0.016-64 μg/mL for erythromycin, and 0.25-64/0.5-128 μg/mL for vancomycin. The n-butanol (n-BuOH) and ethyl acetate (EtOAc) fractions exhibited stronger antibacterial activity against oral bacteria than other fractions and extracts. The MICs and MBCs were reduced to between one half and one quarter when the n-BuOH and EtOAc fractions were combined with antibiotics. After 24 h of incubation, combination of 1/2 MIC of the n-BuOH fraction with antibiotics increased the degree of bactericidal activity. The present results suggest that n-BuOH and EtOAc extracts of S. flavescens root might be applicable as new natural antimicrobial agents against oral pathogens.

Adaptogenic activity of a novel, withanolide-free aqueous fraction from the roots of Withania somnifera Dun.

PubMed

Singh, B; Saxena, A K; Chandan, B K; Gupta, D K; Bhutani, K K; Anand, K K

2001-06-01

The practitioners of the traditional Indian system of medicine regard Withania somnifera Dun. as the 'Indian ginseng'. A new withanolide-free aqueous fraction was isolated from the roots of this plant and was evaluated for putative antistress activity against a battery of tests such as hypoxia time, antifatigue effect, swimming performance time, swimming induced gastric ulceration and hypothermia, immobilization induced gastric ulceration, autoanalgesia and biochemical changes in the adrenal glands. This bioactive fraction exhibited significant antistress activity in a dose-related manner in all the parameters studied. The extract of Withania somnifera root (a commercial preparation available locally) was used to compare the results. A preliminary acute toxicity study in mice showed a good margin of safety. Copyright 2001 John Wiley & Sons, Ltd.

Latent nitrate reductase activity is associated with the plasma membrane of corn roots

NASA Technical Reports Server (NTRS)

Ward, M. R.; Grimes, H. D.; Huffaker, R. C.

1989-01-01

Latent nitrate reductase activity (NRA) was detected in corn (Zea mays L., Golden Jubilee) root microsome fractions. Microsome-associated NRA was stimulated up to 20-fold by Triton X-100 (octylphenoxy polyethoxyethanol) whereas soluble NRA was only increased up to 1.2-fold. Microsome-associated NRA represented up to 19% of the total root NRA. Analysis of microsomal fractions by aqueous two-phase partitioning showed that the membrane-associated NRA was localized in the second upper phase (U2). Analysis with marker enzymes indicated that the U2 fraction was plasma membrane (PM). The PM-associated NRA was not removed by washing vesicles with up to 1.0 M NACl but was solubilized from the PM with 0.05% Triton X-100. In contrast, vanadate-sensitive ATPase activity was not solubilized from the PM by treatment with 0.1% Triton X-100. The results show that a protein capable of reducing nitrate is embedded in the hydrophobic region of the PM of corn roots.

Litter type control on soil C and N stabilization dynamics in a temperate forest.

PubMed

Hatton, Pierre-Joseph; Castanha, Cristina; Torn, Margaret S; Bird, Jeffrey A

2015-03-01

While plant litters are the main source of soil organic matter (SOM) in forests, the controllers and pathways to stable SOM formation remain unclear. Here, we address how litter type ((13) C/(15) N-labeled needles vs. fine roots) and placement-depth (O vs. A horizon) affect in situ C and N dynamics in a temperate forest soil after 5 years. Litter type rather than placement-depth controlled soil C and N retention after 5 years in situ, with belowground fine root inputs greatly enhancing soil C (x1.4) and N (x1.2) retention compared with aboveground needles. While the proportions of added needle and fine root-derived C and N recovered into stable SOM fractions were similar, they followed different transformation pathways into stable SOM fractions: fine root transfer was slower than for needles, but proportionally more of the remaining needle-derived C and N was transferred into stable SOM fractions. The stoichiometry of litter-derived C vs. N within individual SOM fractions revealed the presence at least two pools of different turnover times (per SOM fraction) and emphasized the role of N-rich compounds for long-term persistence. Finally, a regression approach suggested that models may underestimate soil C retention from litter with fast decomposition rates. © 2014 John Wiley & Sons Ltd.

Ca biogeochemical cycle at the beech tree - soil solution interface from the Strengbach CZO (NE France): a clue from stable Ca and radiogenic Sr isotopes

NASA Astrophysics Data System (ADS)

Schmitt, Anne-Désirée; Gangloff, Sophie; Labolle, François; Chabaux, François; Stille, Peter

2017-04-01

Stable calcium and radiogenic Sr are analysed in several organs from two beech trees that were collected in June and September in the Strengbach CZO (NE France) and in corresponding soil solutions. The combination of these two isotopic systems shows that the isotopic signatures of roots are dominated by Ca fractionation mechanisms and Sr, and thus Ca, source variations. In contrast, translocation mechanisms are only governed by Ca fractionation processes. This study also confirms in the field that the Ca uptake mechanisms from nutritive solutions are controlled by adsorption processes in small roots because of physico-chemical mechanisms. Similarly, a study of surface soil solutions suggests that recent soil waters are less affected by vegetation uptake than in the past, probably because of a decline in the growth of the vegetation that is linked to climate warming, which causes drought episodes. Thus, soil solutions reflect the role of soil components in addition to nutrient uptake by vegetation. This isotopic Ca-Sr study also helps to identify one-time events that are caused by snow cover melting and/or dry episodes that release cations.

Land-atmosphere interactions over the continental United States

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

Zeng, Xubin

This paper briefly discusses four suggested modifications for land surface modeling in climate models. The impact of the modifications on climate simulations is analyzed with the Biosphere-Atmosphere Transfer Scheme (BATS) land surface model. It is found that the modifications can improve BATS simulations. In particular, the sensitivity of BATS to the prescribed value of physical root fraction which cannot be observed from satellite remote sensing or field experiments is improved. These modifications significantly reduce the excessive summer land surface temperature over the continental United States simulated by the National Center for Atmospheric Research Community Climate Model (CCM2) coupled with BATS.more » A land-atmosphere interaction mechanism involving energy and water cycles is proposed to explain the results. 9 refs., 1 fig.« less

Modeling vegetation rooting strategies on a hillslope

NASA Astrophysics Data System (ADS)

Sivandran, G.; Bras, R. L.

2011-12-01

The manner in which water and energy is partitioned and redistributed along a hillslope is the result of complex coupled ecohydrological interactions between the climatic, soils, topography and vegetation operating over a wide range of spatiotemporal scales. Distributed process based modeling creates a framework through which the interaction of vegetation with the subtle differences in the spatial and temporal dynamics of soil moisture that arise under localized abiotic conditions along a hillslope can be simulated and examined. One deficiency in the current dynamic vegetation models is the one sided manner in which vegetation responds to soil moisture dynamics. Above ground, vegetation is given the freedom to dynamically evolve through alterations in fractional vegetation cover and/or canopy height and density; however below ground rooting profiles are simplistically represented and often held constant in time and space. The need to better represent the belowground role of vegetation through dynamic rooting strategies is fundamental in capturing the magnitude and timing of water and energy fluxes between the atmosphere and land surface. In order to allow vegetation to adapt to gradients in soil moisture a dynamic rooting scheme was incorporated into tRIBS+VEGGIE (a physically based distributed ecohydrological model). The dynamic rooting scheme allows vegetation the freedom to adapt their rooting depth and distribution in response abiotic conditions in a way that more closely mimics observed plant behavior. The incorporation of this belowground plasticity results in vegetation employing a suite of rooting strategies based on soil texture, climatic conditions and location on the hillslope.

Do oxygen stable isotopes track precipitation moisture source in vascular plant dominated peatlands?

NASA Astrophysics Data System (ADS)

Charman, D.; Amesbury, M. J.; Newnham, R.; Loader, N.; Goodrich, J. P.; Gallego-Sala, A. V.; Royles, J.; Keller, E. D.; Baisden, W. T.

2014-12-01

Variations in the isotopic composition of precipitation are determined by fractionation processes which occur during temperature and humidity dependent phase changes associated with evaporation and condensation. Oxygen stable isotope ratios have therefore been frequently used as a source of palaeoclimate data from a variety of proxy archives. Exploitation of this record from ombrotrophic peatlands, where the source water used in cellulose synthesis is derived solely from precipitation, has been mostly limited to Northern Hemisphere Sphagnum-dominated bogs, with limited application in the Southern Hemisphere (SH) or in peatlands dominated by vascular plants. Throughout New Zealand (NZ), the preserved root matrix of the restionaceous wire rush (Empodisma spp.) forms deep peat deposits. NZ provides an ideal location to undertake empirical research into oxygen isotope fractionation in vascular peatlands because sites are ideally suited to single taxon analysis, preserve potentially high resolution full Holocene palaeoclimate records and are situated in the climatically sensitive SH mid-latitudes. Crucially, large gradients exist in the mean isotopic composition of precipitation across NZ, caused primarily by the relative influence of different climate modes. We test the capacity for δ18O analysis of Empodisma alpha cellulose from ombrotrophic restiad peatlands in NZ to provide a methodology for developing palaeoclimate records. We took surface plant, water and precipitation samples over spatial (six sites spanning >10° latitude) and temporal (monthly measurements over one year) gradients. We found a strong link between the isotopic compositions of surface root water, the most likely source water for plant growth, and precipitation in both datasets. Back-trajectory modelling of precipitation moisture source for rain days prior to sampling showed clear seasonality in the temporal data that was reflected in surface root water. The link between source water and plant cellulose was less clear, although mechanistic modelling predicted mean cellulose values within published error margins for both datasets. Improved understanding and modelling of δ18O in restiad peatlands should enable use of this approach as a new source of palaeoclimate data to reconstruct changes in past atmospheric circulation

Regional structural characteristics of bovine periodontal ligament samples and their suitability for biomechanical tests.

PubMed

Bosshardt, Dieter D; Bergomi, Marzio; Vaglio, Giovanna; Wiskott, Anselm

2008-03-01

Mechanical testing of the periodontal ligament requires a practical experimental model. Bovine teeth are advantageous in terms of size and availability, but information is lacking as to the anatomy and histology of their periodontium. The aim of this study, therefore, was to characterize the anatomy and histology of the attachment apparatus in fully erupted bovine mandibular first molars. A total of 13 teeth were processed for the production of undecalcified ground sections and decalcified semi-thin sections, for NaOH maceration, and for polarized light microscopy. Histomorphometric measurements relevant to the mechanical behavior of the periodontal ligament included width, number, size and area fraction of blood vessels and fractal analysis of the two hard-soft tissue interfaces. The histological and histomorphometric analyses were performed at four different root depths and at six circumferential locations around the distal and mesial roots. The variety of techniques applied provided a comprehensive view of the tissue architecture of the bovine periodontal ligament. Marked regional variations were observed in width, surface geometry of the two bordering hard tissues (cementum and alveolar bone), structural organization of the principal periodontal ligament connective tissue fibers, size, number and numerical density of blood vessels in the periodontal ligament. No predictable pattern was observed, except for a statistically significant increase in the area fraction of blood vessels from apical to coronal. The periodontal ligament width was up to three times wider in bovine teeth than in human teeth. The fractal analyses were in agreement with the histological observations showing frequent signs of remodeling activity in the alveolar bone - a finding which may be related to the magnitude and direction of occlusal forces in ruminants. Although samples from the apical root portion are not suitable for biomechanical testing, all other levels in the buccal and lingual aspects of the mesial and distal roots may be considered. The bucco-mesial aspect of the distal root appears to be the most suitable location.

In Vivo Antimalarial Activity of the Solvent Fractions of Fruit Rind and Root of Carica papaya Linn (Caricaceae) against Plasmodium berghei in Mice

PubMed Central

Kebebe, Dereje; Mulisa, Eshetu; Gashe, Fanta

2017-01-01

Background Currently, antimalarial drug resistance poses a serious challenge. This stresses the need for newer antimalarial compounds. Carica papaya is used traditionally and showed in vitro antimalarial activity. This study attempted to evaluate in vivo antimalarial activity of C. papaya in mice. Methods In vivo antimalarial activity of solvent fractions of the plant was carried out against early P. berghei infection in mice. Parasitemia, temperature, PCV, and body weight of mice were recorded. Windows SPSS version 16 (one-way ANOVA followed by Tukey's post hoc test) was used for data analysis. Results The pet ether and chloroform fractions of C. papaya fruit rind and root produced a significant (p < 0.001) chemosuppressive effect. A maximum parasite suppression of 61.78% was produced by pet ether fraction of C. papaya fruit rind in the highest dose (400 mg/kg/day). Only 400 mg/kg/day dose of chloroform fraction of C. papaya root exhibited a parasite suppression effect (48.11%). But, methanol fraction of the plant parts produced less chemosuppressive effect. Conclusion Pet ether fraction of C. papaya fruit rind had the highest antimalarial activity and could be a potential source of lead compound. Further study should be done to show the chemical and metabolomic profile of active ingredients. PMID:29391947

In vitro cytotoxicity of nonpolar constituents from different parts of kava plant (Piper methysticum).

PubMed

Jhoo, Jin-Woo; Freeman, James P; Heinze, Thomas M; Moody, Joanna D; Schnackenberg, Laura K; Beger, Richard D; Dragull, Klaus; Tang, Chung-Shih; Ang, Catharina Y W

2006-04-19

Kava (Piper methysticum), a perennial shrub native to the South Pacific islands, has been used to relieve anxiety. Recently, several cases of severe hepatotoxicity have been reported from the consumption of dietary supplements containing kava. It is unclear whether the kava constituents, kavalactones, are responsible for the associated hepatotoxicity. To investigate the key components responsible for the liver toxicity, bioassay-guided fractionation was carried out in this study. Kava roots, leaves, and stem peelings were extracted with methanol, and the resulting residues were subjected to partition with a different polarity of solvents (hexane, ethyl acetate, n-butanol, and water) for evaluation of their cytotoxicity on HepG2 cells based on the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and lactate dehydrogenase and aspartate aminotransferase enzyme leakage assays. Organic solvent fractions displayed a much stronger cytotoxicity than water fractions for all parts of kava. The hexane fraction of the root exhibited stronger cytotoxic effects than fractions of root extracted with other solvents or extracts from the other parts of kava. Further investigations using bioassay-directed isolation and analysis of the hexane fraction indicated that the compound responsible for the cytotoxicity was flavokavain B. The identity of the compound was confirmed by (1)H and (13) C NMR and MS techniques.

Negligible fractionation of Kr and Xe isotopes by molecular diffusion in water

NASA Astrophysics Data System (ADS)

Tyroller, Lina; Brennwald, Matthias S.; Busemann, Henner; Maden, Colin; Baur, Heinrich; Kipfer, Rolf

2018-06-01

Molecular diffusion is a key transport process for noble gases in water. Such diffusive transport is often thought to cause a mass-dependent fractionation of noble gas isotopes that is inversely proportional to the square root of the ratio of their atomic mass, referred to as the square root relation. Previous studies, challenged the commonly held assumption that the square root relation adequately describes the behaviour of noble gas isotopes diffusing through water. However, the effect of diffusion on noble gas isotopes has only been determined experimentally for He, Ne and Ar to date, whereas the extent of fractionation of Kr and Xe has not been measured. In the present study the fractionation of Kr and Xe isotopes diffusing through water immobilised by adding agar was quantified through measuring the respective isotope ratio after diffusing through the immobilised water. No fractionation of Kr and Xe isotopes was observed, even using high-precision noble gas analytics. These results complement our current understanding on isotopic fractionation of noble gases diffusing through water. Therefore this complete data set builds a robust basis to describe molecular diffusion of noble gases in water in a physical sound manner which is fundamental to assess the physical aspects of gas dynamics in aquatic systems.

Digging a Little Deeper: Microbial Communities, Molecular Composition and Soil Organic Matter Turnover along Tropical Forest Soil Depth Profiles

NASA Astrophysics Data System (ADS)

Pett-Ridge, J.; McFarlane, K. J.; Heckman, K. A.; Reed, S.; Green, E. A.; Nico, P. S.; Tfaily, M. M.; Wood, T. E.; Plante, A. F.

2016-12-01

Tropical forest soils store more carbon (C) than any other terrestrial ecosystem and exchange vast amounts of CO2, water, and energy with the atmosphere. Much of this C is leached and stored in deep soil layers where we know little about its fate or the microbial communities that drive deep soil biogeochemistry. Organic matter (OM) in tropical soils appears to be associated with mineral particles, suggesting deep soils may provide greater C stabilization. However, few studies have evaluated sub-surface soils in tropical ecosystems, including estimates of the turnover times of deep soil C, the sensitivity of this C to global environmental change, and the microorganisms involved. We quantified bulk C pools, microbial communities, molecular composition of soil organic matter, and soil radiocarbon turnover times from surface soils to 1.5m depths in multiple soil pits across the Luquillo Experimental Forest, Puerto Rico. Soil C, nitrogen, and root and microbial biomass all declined exponentially with depth; total C concentrations dropped from 5.5% at the surface to <0.5% at 140cm depth. High-throughput sequencing highlighted distinct microbial communities in surface soils (Acidobacteria and Proteobacteria) versus those below the active rooting zone (Verrucomicrobia and Thaumarchaea). High resolution mass spectrometry (FTICR-MS) analyses suggest a shift in the composition of OM with depth (especially in the water soluble fraction), an increase in oxidation, and decreasing H/C with depth (indicating higher aromaticity). Additionally, surface samples were rich in lignin-like compounds of plant origin that were absent with depth. Soil OM 14C and mean turnover times were variable across replicate horizons, ranging from 3-1500 years at the surface, to 5000-40,000 years at depth. In comparison to temperate deciduous forests, these 14C values reflect far older soil C. Particulate organic matter (free light fraction), with a relatively modern 14C was found in low but measureable concentration in even the deepest soil horizons. Our results indicate these tropical subsoils contain small but metabolically active microbial communities that are highly OM limited and may persist via degradation of recent inputs.

Extraction and Isolation of Antineoplastic Pristimerin from Mortonia greggii (Celastraceae).

PubMed

Mejia-Manzano, Luis Alberto; Barba-Dávila, Bertha A; Gutierrez-Uribe, Janet A; Escalante-Vázquez, Edgardo J; Serna-Saldivar, Sergio O

2015-11-01

The aim of this research was to identify, extract and isolate pristimerin in leaves, stems and roots of the Mexican plant Mortonia greggii (Celastraceae). The principal objective was to determine the best laboratory experimental conditions for the extraction and isolation of this powerful natural anticancer agent from the root tissue. Six experimental factors in solid-liquid pristimerin extraction were analyzed: solvent systems, number of extractions, ratio of plant weight (g)/solvent volume (mL) used, time of extraction, temperature and agitation. A mathematical model was generated for pristimerin purity and yield. Ethanol, first extraction, 0.5 ratio of plant weight/solvent volume (g/mL), 0.5 h, 200 rpm and 49.7°C were optimal conditions for the extraction of this phytochemical. The degree of purification of pristimerin root extract was studied by size-exclusion chromatography (SEC) using Sephadex LH-20 reaching fractions with purification indexes (PI) greater than 2 and recoveries of 28.3%. When fractions with purification indices higher than 1 and less than 2 were accumulated, the recovery of pristimerin increased by about 73.6%. By combining the optimum extracts and SEC purification protocols, an enriched fraction containing 245.6 mg pristimerin was obtained from 100 g of root bark, representing about 14.4%, w/w, pristimerin from the total solids presented in the fraction.

Characterisation of antimicrobial extracts from dandelion root (Taraxacum officinale) using LC-SPE-NMR.

PubMed

Kenny, O; Brunton, N P; Walsh, D; Hewage, C M; McLoughlin, P; Smyth, T J

2015-04-01

Plant extracts have traditionally been used as sources of natural antimicrobial compounds, although in many cases, the compounds responsible for their antimicrobial efficacy have not been identified. In this study, crude and dialysed extracts from dandelion root (Taraxacum officinale) were evaluated for their antimicrobial properties against Gram positive and Gram negative bacterial strains. The methanol hydrophobic crude extract (DRE3) demonstrated the strongest inhibition of microbial growth against Staphylococcus aureus, methicillin-resistant S. aureus and Bacillus cereus strains. Normal phase (NP) fractionation of DRE3 resulted in two fractions (NPF4 and NPF5) with enhanced antimicrobial activity. Further NP fractionation of NPF4 resulted in two fractions (NPF403 and NPF406) with increased antimicrobial activity. Further isolation and characterisation of compounds in NPF406 using liquid chromatography solid phase extraction nuclear magnetic resonance LC-SPE-NMR resulted in the identification of 9-hydroxyoctadecatrienoic acid and 9-hydroxyoctadecadienoic acid, while the phenolic compounds vanillin, coniferaldehyde and p-methoxyphenylglyoxylic acid were also identified respectively. The molecular mass of these compounds was confirmed by LC mass spectroscopy (MS)/MS. In summary, the antimicrobial efficacy of dandelion root extracts demonstrated in this study support the use of dandelion root as a source of natural antimicrobial compounds. Copyright © 2015 John Wiley & Sons, Ltd.

Antibacterial activities of the methanol extracts, fractions and compounds from Fagara tessmannii.

PubMed

Tankeo, Simplice B; Damen, Francois; Awouafack, Maurice D; Mpetga, James; Tane, Pierre; Eloff, Jacobus N; Kuete, Victor

2015-07-01

Fagara tessmannii is a shrub of the African rainforests used to treat bacterial infections, cancers, swellings and inflammation. In the present study, the methanol extract from the leaves (FTL), bark (FTB), and roots (FTR) of this plant as well as fractions (FTR1-5) and compounds isolated from FTR namely β-sitosterol-3-O-β-d-glucopyranoside (1), nitidine chloride (2) and buesgenine (3), were tested for their antimicrobial activities against a panel of Gram-negative bacteria including multidrug resistant (MDR) phenotypes. The broth microdilution method was used to determine the minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) of the above samples; Column chromatography was used for the fractionation and purification of the roots extract whilst the chemical structures of compounds were determined using spectroscopic techniques. Results of the MIC determinations indicated that the crude extracts from the roots as well as fraction FTRa4 were active on all the 26 tested bacterial strains. MIC values below 100µg/mL were obtained with roots, leaves and bark extract respectively against 30.8%, 15.4% and 11.5% tested bacteria. The lowest MIC value below of 8µg/mL was obtained with extract from the roots against Escherichia coli MC100 strain. The lowest MIC value of 4µg/mL was also obtained with compound 3 against E. coli AG102 and Klebsiella pneumoniae ATCC11296 CONCLUSIONS: The present study demonstrates that F. tessmannii is a potential source of antimicrobial drugs to fight against MDR bacteria. Benzophenanthrine alkaloids 2 and 3 are the main antibacterial consituents of the roots of the plant. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Molar crown and root size relationship in anthropoid primates.

PubMed

Kupczik, Kornelius; Olejniczak, Anthony J; Skinner, Matthew M; Hublin, Jean-Jacques

2009-01-01

Mandibular corpus form is thought to reflect masticatory function and the size of the dentition, but there is no universal association between crown dimensions and corpus size across anthropoids. Previous research was based on the assumption that crown size is an appropriate proxy for overall tooth size, but this hypothesis remains largely untested. This study assesses the relationship between the volume and surface area of molar crowns and roots by examining two main hypotheses: (1) crown size correlates significantly with root size, and (2) the proportion of root-to-crown surface area is related to dietary proclivity. Permanent M2s (n=58) representing 19 anthropoid species were CT scanned and the volume and surface area of the crown and root were measured. Interspecific correlation and regression analyses reveal significant isometric relationships between crown and root volume and a positive allometric relationship between root and crown surface area (i.e. as crown surface area increases, root surface area becomes disproportionately greater). Intraspecifically, crown and root surface area correlate significantly in some species where such analyses were possible. In general, hard object feeders exhibit relatively larger root surface area per unit crown surface area compared to soft and tough object feeders. The results also show that despite differences in food specialization closely related species have similar root-to-crown surface area proportions, thus indicating a strong phylogenetic influence. Since it is possible that, at least in some species, crown and root size vary independently, future studies should elucidate the relationship between tooth root size and mandible form. Copyright (c) 2009 S. Karger AG, Basel.

In vitro anthelmintic effects of Spigelia anthelmia protein fractions against Haemonchus contortus.

PubMed

Araújo, Sandra Alves; Soares, Alexandra Martins Dos Santos; Silva, Carolina Rocha; Almeida Júnior, Eduardo Bezerra; Rocha, Cláudia Quintino; Ferreira, André Teixeira da Silva; Perales, Jonas; Costa-Júnior, Livio M

2017-01-01

Gastrointestinal nematodes are a significant concern for animal health and well-being, and anthelmintic treatment is mainly performed through the use of chemical products. However, bioactive compounds produced by plants have shown promise for development as novel anthelmintics. The aim of this study is to assess the anthelmintic activity of protein fractions from Spigelia anthelmia on the gastrointestinal nematode Haemonchus contortus. Plant parts were separated into leaves, stems and roots, washed with distilled water, freeze-dried and ground into a fine powder. Protein extraction was performed with sodium phosphate buffer (75 mM, pH 7.0). The extract was fractionated using ammonium sulfate (0-90%) and extensively dialyzed. The resulting fractions were named LPF (leaf protein fraction), SPF (stem protein fraction) and RPF (root protein fraction), and the protein contents and activities of the fractions were analyzed. H. contortus egg hatching (EHA), larval exsheathment inhibition (LEIA) and larval migration inhibition (LMIA) assays were performed. Proteomic analysis was conducted, and high-performance liquid chromatography (HPLC) chromatographic profiles of the fractions were established to identify proteins and possible secondary metabolites. S. anthelmia fractions inhibited H. contortus egg hatching, with LPF having the most potent effects (EC50 0.17 mg mL-1). During LEIA, SPF presented greater efficiency than the other fractions (EC50 0.25 mg mL-1). According to LMIA, the fractions from roots, stems and leaves also reduced the number of larvae, with EC50 values of 0.11, 0.14 and 0.21 mg mL-1, respectively. Protein analysis indicated the presence of plant defense proteins in the S. anthelmia fractions, including protease, protease inhibitor, chitinase and others. Conversely, secondary metabolites were absent in the S. anthemia fractions. These results suggest that S. anthelmia proteins are promising for the control of the gastrointestinal nematode H. contortus.

RIP-ET: A riparian evapotranspiration package for MODFLOW-2005

USGS Publications Warehouse

Maddock, Thomas; Baird, Kathryn J.; Hanson, R.T.; Schmid, Wolfgang; Ajami, Hoori

2012-01-01

A new evapotranspiration package for the U.S. Geological Survey's groundwater-flow model, MODFLOW, is documented. The Riparian Evapotranspiration Package (RIP-ET) provides flexibility in simulating riparian and wetland transpiration not provided by the Evapotranspiration (EVT) or Segmented Function Evapotranspiration (ETS1) Packages for MODFLOW 2005. This report describes how the RIP-ET package was conceptualized and provides input instructions, listings and explanations of the source code, and an example. Traditional approaches to modeling evapotranspiration (ET) processes assume a piecewise linear relationship between ET flux and hydraulic head. The RIP-ET replaces this traditional relationship with a segmented, nonlinear dimensionless curve that reflects the eco-physiology of riparian and wetland ecosystems. Evapotranspiration losses from these ecosystems are dependent not only on hydraulic head, but on the plant types present. User-defined plant functional groups (PFGs) are used to elucidate the interaction between plant transpiration and groundwater conditions. Five generalized plant functional groups based on transpiration rates, plant rooting depth, and water tolerance ranges are presented: obligate wetland, shallow-rooted riparian, deep-rooted riparian, transitional riparian and bare ground/open water. Plant functional groups can be further divided into subgroups (PFSGs) based on plant size, density or other characteristics. The RIP-ET allows for partial habitat coverage and mixtures of plant functional subgroups to be present in a single model cell. RIP-ET also distinguishes between plant transpiration and bare-ground evaporation. Habitat areas are designated by polygons; each polygon can contain a mixture of PFSGs and bare ground, and is assigned a surface elevation. This process requires a determination of fractional coverage for each of the plant functional subgroups present in a polygon to account for the mixture of coverage types and resulting transpiration. The fractional cover within a cell has two components: (1) the polygonal fraction of active habitat (excluding area of bare ground, dead trees, or brush) in a cell, and (2) fraction of plant type area or bare ground area in a polygon. RIP-ET determines the transpiration rate for each plant functional group and evaporation from bare ground/open water in a cell, the total ET in the cell, and the total ET rate over the region of simulation.

Silicon isotope fractionation in bamboo and its significance to the biogeochemical cycle of silicon

NASA Astrophysics Data System (ADS)

Ding, T. P.; Zhou, J. X.; Wan, D. F.; Chen, Z. Y.; Wang, C. Y.; Zhang, F.

2008-03-01

A systematic investigation on silica contents and silicon isotope compositions of bamboos was undertaken. Seven bamboo plants and related soils were collected from seven locations in China. The roots, stem, branch and leaves for each plant were sampled and their silica contents and silicon isotope compositions were determined. The silica contents and silicon isotope compositions of bulk and water-soluble fraction of soils were also measured. The silica contents of studied bamboo organs vary from 0.30% to 9.95%. Within bamboo plant the silica contents show an increasing trend from stem, through branch, to leaves. In bamboo roots the silica is exclusively in the endodermis cells, but in stem, branch and leaves, the silica is accumulated mainly in epidermal cells. The silicon isotope compositions of bamboos exhibit significant variation, from -2.3‰ to 1.8‰, and large and systematic silicon isotope fractionation was observed within each bamboo. The δ 30Si values decrease from roots to stem, but then increase from stem, through branch, to leaves. The ranges of δ 30Si values within each bamboo vary from 1.0‰ to 3.3‰. Considering the total range of silicon isotope composition in terrestrial samples is only 7‰, the observed silicon isotope variation in single bamboo is significant and remarkable. This kind of silicon isotope variation might be caused by isotope fractionation in a Rayleigh process when SiO 2 precipitated in stem, branches and leaves gradually from plant fluid. In this process the Si isotope fractionation factor between dissolved Si and precipitated Si in bamboo ( αpre-sol) is estimated to be 0.9981. However, other factors should be considered to explain the decrease of δ 30Si value from roots to stem, including larger ratio of dissolved H 4SiO 4 to precipitated SiO 2 in roots than in stem. There is a positive correlation between the δ 30Si values of water-soluble fractions in soils and those of bulk bamboos, indicating that the dissolved silicon in pore water and phytoliths in soil is the direct sources of silicon taken up by bamboo roots. A biochemical silicon isotope fractionation exists in process of silicon uptake by bamboo roots. Its silicon isotope fractionation factor ( αbam-wa) is estimated to be 0.9988. Considering the distribution patterns of SiO 2 contents and δ 30Si values among different bamboo organs, evapotranspiration may be the driving force for an upward flow of a silicon-bearing fluid and silica precipitation. Passive silicon uptake and transportation may be important for bamboo, although the role of active uptake of silicic acid by roots may not be neglected. The samples with relatively high δ 30Si values all grew in soils showing high content of organic materials. In contrast, the samples with relatively low δ 30Si values all grew in soil showing low content of organic materials. The silicon isotope composition of bamboo may reflect the local soil type and growth conditions. Our study suggests that bamboos may play an important role in global silicon cycle.

Adding Some Perspective to de Moivre's Theorem: Visualising the "n"-th Roots of Unity

ERIC Educational Resources Information Center

Bardell, Nicholas S.

2015-01-01

Traditionally, "z" is assumed to be a complex number and the roots are usually determined by using de Moivre's theorem adapted for fractional indices. The roots are represented in the Argand plane by points that lie equally pitched around a circle of unit radius. The "n"-th roots of unity always include the real number 1, and…

Interpreting spectral unmixing coefficients: From spectral weights to mass fractions

NASA Astrophysics Data System (ADS)

Grumpe, Arne; Mengewein, Natascha; Rommel, Daniela; Mall, Urs; Wöhler, Christian

2018-01-01

It is well known that many common planetary minerals exhibit prominent absorption features. Consequently, the analysis of spectral reflectance measurements has become a major tool of remote sensing. Quantifying the mineral abundances, however, is not a trivial task. The interaction between the incident light rays and particulate surfaces, e.g., the lunar regolith, leads to a non-linear relationship between the reflectance spectra of the pure minerals, the so-called ;endmembers;, and the surface's reflectance spectrum. It is, however, possible to transform the non-linear reflectance mixture into a linear mixture of single-scattering albedos of the Hapke model. The abundances obtained by inverting the linear single-scattering albedo mixture may be interpreted as volume fractions which are weighted by the endmember's extinction coefficient. Commonly, identical extinction coefficients are assumed throughout all endmembers and the obtained volume fractions are converted to mass fractions using either measured or assumed densities. In theory, the proposed method may cover different grain sizes if each grain size range of a mineral is treated as a distinct endmember. Here, we present a method to transform the mixing coefficients to mass fractions for arbitrary combinations of extinction coefficients and densities. The required parameters are computed from reflectance measurements of well defined endmember mixtures. Consequently, additional measurements, e.g., the endmember density, are no longer required. We evaluate the method based on laboratory measurements and various results presented in the literature, respectively. It is shown that the procedure transforms the mixing coefficients to mass fractions yielding an accuracy comparable to carefully calibrated laboratory measurements without additional knowledge. For our laboratory measurements, the square root of the mean squared error is less than 4.82 wt%. In addition, the method corrects for systematic effects originating from mixtures of endmembers showing a highly varying albedo, e.g., plagioclase and pyroxene.

Anti-acetylcholinesterase activity and antioxidant properties of extracts and fractions of Carpolobia lutea.

PubMed

Nwidu, Lucky Legbosi; Elmorsy, Ekramy; Thornton, Jack; Wijamunige, Buddhika; Wijesekara, Anusha; Tarbox, Rebecca; Warren, Averil; Carter, Wayne Grant

2017-12-01

There is an unmet need to discover new treatments for Alzheimer's disease. This study determined the anti-acetylcholinesterase (AChE) activity, DPPH free radical scavenging and antioxidant properties of Carpolobia lutea G. Don (Polygalaceae). The objective of this study is to quantify C. lutea anti-AChE, DPPH free radical scavenging, and antioxidant activities and cell cytotoxicity. Plant stem, leaves and roots were subjected to sequential solvent extractions, and screened for anti-AChE activity across a concentration range of 0.02-200 μg/mL. Plant DPPH radical scavenging activity, reducing power, and total phenolic and flavonoid contents were determined, and cytotoxicity evaluated using human hepatocytes. Carpolobia lutea exhibited concentration-dependent anti-AChE activity. The most potent inhibitory activity for the stem was the crude ethanol extract and hexane stem fraction oil (IC 50  = 140 μg/mL); for the leaves, the chloroform leaf fraction (IC 50  = 60 μg/mL); and for roots, the methanol, ethyl acetate and aqueous root fractions (IC 50  = 0.3-3 μg/mL). Dose-dependent free radical scavenging activity and reducing power were observed with increasing stem, leaf or root concentration. Total phenolic contents were the highest in the stem: ∼632 mg gallic acid equivalents/g for a hexane stem fraction oil. Total flavonoid content was the highest in the leaves: ∼297 mg quercetin equivalents/g for a chloroform leaf fraction. At 1 μg/mL, only the crude ethanol extract oil was significantly cytotoxic to hepatocytes. Carpolobia lutea possesses anti-AChE activity and beneficial antioxidant capacity indicative of its potential development as a treatment of Alzheimer's and other diseases characterized by a cholinergic deficit.

In Situ Analyses of Methane Oxidation Associated with the Roots and Rhizomes of a Bur Reed, Sparganium Eurycarpum, in a Maine Wetland

NASA Technical Reports Server (NTRS)

King, Gary M.

1996-01-01

Methane oxidation associated with the belowground tissues of a common aquatic macrophyte, the burweed Sparganium euryearpum, was assayed in situ by a chamber technique with acetylene or methyl fluoride as a methanotrophic inhibitor at a headspace concentration of 3 to 4%. Acetylene and methyl fluoride inhibited both methane oxidation and peat methanogenesis. However, inhibition of methanogenesis resulted in no obvious short-term effect on methane fluxes. Since neither inhibitor adversely affected plant metabolism and both inhibited methanotrophy equally well, acetylene was employed for routine assays because of its low cost and ease of use. Root-associated methanotrophy consumed a variable but significant fraction of the total potential methane flux; values varied between 1 and 58% (mean +/- standard deviation, 27.0% +/- 6.0%), with no consistent temporal or spatial pattern during late summer. The absolute amount of methane oxidized was not correlated with the total potential methane flux; this suggested that parameters other than methane availability (e.g., oxygen availability) controlled the rates of methane oxidation. Estimates of diffusive methane flux and oxidation at the peat surface indicated that methane emission occurred primarily through aboveground plant tissues; the absolute magnitude of methane oxidation was also greater in association with roots than at the peat surface. However, the relative extent of oxidation was greater at the latter locus.

Barley root hair growth and morphology in soil, sand, and water solution media and relationship with nickel toxicity.

PubMed

Lin, Yanqing; Allen, Herbert E; Di Toro, Dominic M

2016-08-01

Barley, Hordeum vulgare (Doyce), was grown in the 3 media of soil, hydroponic sand solution (sand), and hydroponic water solution (water) culture at the same environmental conditions for 4 d. Barley roots were scanned, and root morphology was analyzed. Plants grown in the 3 media had different root morphology and nickel (Ni) toxicity response. Root elongations and total root lengths followed the sequence soil > sand > water. Plants grown in water culture were more sensitive to Ni toxicity and had greater root hair length than those from soil and sand cultures, which increased root surface area. The unit root surface area as root surface area per centimeter of length of root followed the sequence water > sand > soil and was found to be related with root elongation. Including the unit root surface area, the difference in root elongation and 50% effective concentration were diminished, and percentage of root elongations can be improved with a root mean square error approximately 10% for plants grown in different media. Because the unit root surface area of plants in sand culture is closer to that in soil culture, the sand culture method, not water culture, is recommended for toxicity parameter estimation. Environ Toxicol Chem 2016;35:2125-2133. © 2016 SETAC. © 2016 SETAC.

Transpiration flow controls Zn transport in Brassica napus and Lolium multiflorum under toxic levels as evidenced from isotopic fractionation

NASA Astrophysics Data System (ADS)

Couder, Eléonore; Mattielli, Nadine; Drouet, Thomas; Smolders, Erik; Delvaux, Bruno; Iserentant, Anne; Meeus, Coralie; Maerschalk, Claude; Opfergelt, Sophie; Houben, David

2015-11-01

Stable zinc (Zn) isotope fractionation between soil and plant has been used to suggest the mechanisms affecting Zn uptake under toxic conditions. Here, changes in Zn isotope composition in soil, soil solution, root and shoot were studied for ryegrass (Lolium multiflorum L.) and rape (Brassica napus L.) grown on three distinct metal-contaminated soils collected near Zn smelters (total Zn 0.7-7.5%, pH 4.8-7.3). The Zn concentrations in plants reflected a toxic Zn supply. The Zn isotopic fingerprint of total soil Zn varied from -0.05‰ to +0.26 ± 0.02‰ (δ66Zn values relative to the JMC 3-0749L standard) among soils, but the soil solution Zn was depleted in 66Zn, with a constant Zn isotope fractionation of about -0.1‰ δ66Zn unit compared to the bulk soil. Roots were enriched with 66Zn relative to soil solution (δ66Znroot - δ66Znsoil solution = Δ66Znroot-soil solution = +0.05 to +0.2 ‰) and shoots were strongly depleted in 66Zn relative to roots (Δ66Znshoot-root = -0.40 to -0.04 ‰). The overall δ66Zn values in shoots reflected that of the bulk soil, but were lowered by 0.1-0.3 ‰ units as compared to the latter. The isotope fractionation between root and shoot exhibited a markedly strong negative correlation (R2 = 0.83) with transpiration per unit of plant weight. Thus, the enrichment with light Zn isotopes in shoot progressed with increasing water flux per unit plant biomass dry weight, showing a passive mode of Zn transport by transpiration. Besides, the light isotope enrichment in shoots compared to roots was larger for rape than for rye grass, which may be related to the higher Zn retention in rape roots. This in turn may be related to the higher cation exchange capacity of rape roots. Our finding can be of use to trace the biogeochemical cycles of Zn and evidence the tolerance strategies developed by plants in Zn-excess conditions.

Influence of sulfur on the accumulation of mercury in rice plant (Oryza sativa L.) growing in mercury contaminated soils.

PubMed

Li, Yunyun; Zhao, Jiating; Guo, Jingxia; Liu, Mengjiao; Xu, Qinlei; Li, Hong; Li, Yu-Feng; Zheng, Lei; Zhang, Zhiyong; Gao, Yuxi

2017-09-01

Sulfur (S) is an essential element for plant growth and its biogeochemical cycling is strongly linked to the species of heavy metals in soil. In this work, the effects of S (sulfate and elemental sulfur) treatment on the accumulation, distribution and chemical forms of Hg in rice growing in Hg contaminated soil were investigated. It was found that S could promote the formation of iron plaque on the root surface and decrease total mercury (T-Hg) and methylmercury (MeHg) accumulation in rice grains, straw, and roots. Hg in the root was dominated in the form of RS-Hg-SR. Sulfate treatment increased the percentage of RS-Hg-SR to T-Hg in the rice root and changed the Hg species in soil. The dominant Hg species (70%) in soil was organic substance bound fractions. Sulfur treatment decreased Hg motility in the rhizosphere soils by promoting the conversion of RS-Hg-SR to HgS. This study is significant since it suggests that low dose sulfur treatment in Hg-containing water irrigated soil can decrease both T-Hg and MeHg accumulation in rice via inactivating Hg in the soil and promoting the formation of iron plaque in rice root, which may reduce health risk for people consuming those crops. Copyright © 2017. Published by Elsevier Ltd.

Inter-Annual Variability of Soil Moisture Stress Function in the Wheat Field

NASA Astrophysics Data System (ADS)

Akuraju, V. R.; Ryu, D.; George, B.; Ryu, Y.; Dassanayake, K. B.

2014-12-01

Root-zone soil moisture content is a key variable that controls the exchange of water and energy fluxes between land and atmosphere. In the soil-vegetation-atmosphere transfer (SVAT) schemes, the influence of root-zone soil moisture on evapotranspiration (ET) is parameterized by the soil moisture stress function (SSF). Dependence of actual ET: potential ET (fPET) or evaporative fraction to the root-zone soil moisture via SSF can also be used inversely to estimate root-zone soil moisture when fPET is estimated by remotely sensed land surface states. In this work we present fPET versus available soil water (ASW) in the root zone observed in the experimental farm sites in Victoria, Australia in 2012-2013. In the wheat field site, fPET vs ASW exhibited distinct features for different soil depth, net radiation, and crop growth stages. Interestingly, SSF in the wheat field presented contrasting shapes for two cropping years of 2012 and 2013. We argue that different temporal patterns of rainfall (and resulting soil moisture) during the growing seasons in 2012 and 2013 are responsible for the distinctive SSFs. SSF of the wheat field was simulated by the Agricultural Production Systems sIMulator (APSIM). The APSIM was able to reproduce the observed fPET vs. ASW. We discuss implications of our findings for existing modeling and (inverse) remote sensing approaches relying on SSF and alternative growth-stage-dependent SSFs.

Kinetic Analysis of Phospholipase C from Catharanthus roseus Transformed Roots Using Different Assays1

PubMed Central

Hernández-Sotomayor, S.M. Teresa; De Los Santos-Briones, César; Muñoz-Sánchez, J. Armando; Loyola-Vargas, Victor M.

1999-01-01

The properties of phospholipase C (PLC) partially purified from Catharanthus roseus transformed roots were analyzed using substrate lipids dispersed in phospholipid vesicles, phospholipid-detergent mixed micelles, and phospholipid monolayers spread at an air-water interface. Using [33P]phosphatidylinositol 4,5-bisphosphate (PIP2) of high specific radioactivity, PLC activity was monitored directly by measuring the loss of radioactivity from monolayers as a result of the release of inositol phosphate and its subsequent dissolution on quenching in the subphase. PLC activity was markedly affected by the surface pressure of the monolayer, with reduced activity at extremes of initial pressure. The optimum surface pressure for PIP2 hydrolysis was 20 mN/m. Depletion of PLC from solution by incubation with sucrose-loaded PIP2 vesicles followed by ultracentrifugation demonstrated stable attachment of PLC to the vesicles. A mixed micellar system was established to assay PLC activity using deoxycholate. Kinetic analyses were performed to determine whether PLC activity was dependent on both bulk PIP2 and PIP2 surface concentrations in the micelles. The interfacial Michaelis constant was calculated to be 0.0518 mol fraction, and the equilibrium dissociation constant of PLC for the lipid was 45.5 μm. These findings will add to our understanding of the mechanisms of regulation of plant PLC. PMID:10444091

Use of Rhizosphere Metabolomics to Investigate Exudation of Phenolics by Arabidopsis Roots

NASA Astrophysics Data System (ADS)

Lee, Yong Jian; Rai, Amit; Reuben, Sheela; Nesati, Victor; Almeida, Reinaldo; Swarup, Sanjay

2013-04-01

The rhizosphere is a specialised micro-niche for bacteria that have an active exchange of signals and nutrients with the host plant. Nearly 20% of photosynthates are released as root exudates, which consist of primary metabolites and products of secondary metabolism which are largely phenolic in nature. Previously, using rhizosphere metabolomics, we showed that nearly 50% of organic carbon in the exudates is in the form of phenolic compounds, of which the largest fraction is from the phenylpropanoid synthesis pathway. Using Arabidopsis as a model, we have demonstrated that a biased rhizosphere can be created using plants with varying levels of phenylpropanoids due to mutations in the biosynthetic or regulatory genes. These phenylpropanoids levels are reflected in the exudates, and exudates from lines with regulatory gene mutations, tt8 and ttg, have higher levels of phenylpropanoids, whereas biosynthetic mutant line, tt4, has very low and undetectable levels of phenylpropanoids. The biased rhizosphere of tt8 and ttg lines provides a nutritional advantage to rhizobacteria that can utilize these phenylpropanoids such as quercetin. With such a strategy to increase the competitiveness of plant growth-promoting rhizobacteria (PGPR) such as Pseudomonas putida, this system can be applied to improve plant performance. In order to better understand the metabolic basis of the nutritional advantage behind the competitiveness of the favoured P. putida, we elucidated its quercetin utilization pathway. We have recently cloned the gene for quercetin oxidoreductase (QuoA) and expressed it in transgenic Arabidopsis lines to alter the plant phenylpropanoid metabolism, using a gain of function approach. Since phenylpropanoid biosynthesis in plants involve formation of quercetin from naringenin, we envisaged that QuoA expression in plants will provide us with a genetic tool to "reverse" this biosynthetic step. This perturbation led to a decrease in flavonoids and an increase in lignin and anthocyanin metabolites. We describe here the metabolites present in the root exudates using high resolution accurate mass (HRAM) metabolomics approach. Using this approach, biased rhizosphere for another class of PGPR strains can now be created. In this case, lignin- and anthocyanin- utilizing strains will be selectively preferred. We have set up a platform to perform metabolomics of exudates at the root surface. This has allowed us to use the liquid extraction surface analysis (LESA) system using a Thermo Velos Pro Orbitrap-MS to identify differences in exudate profiles along the root system of Arabidopsis. This platform enables direct sampling and measurement from plant roots grown aeroponically. As the metabolites are extracted from root surface and directly injected into the mass spectrometer, there is minimal loss of sample in this process. This method will now allow us to further dissect rhizosphere properties from places such as young root apex, as well as from the more mature base of roots. Taken together, these resources of altered rhizosphere, nutrient utilization pathways in microbes and surface analysis technology will help in extending our understanding of the processes in the plant rhizosphere.

Identification of qSOR1, a major rice QTL involved in soil-surface rooting in paddy fields.

PubMed

Uga, Yusaku; Hanzawa, Eiko; Nagai, Shinsei; Sasaki, Kazuhiro; Yano, Masahiro; Sato, Tadashi

2012-01-01

Specific Indonesian lowland rice (Oryza sativa L.) cultivars elongate thick primary roots on the soil surface of paddy fields. To clarify the genetic factors controlling soil-surface rooting, we performed quantitative trait locus (QTL) analyses using 124 recombinant inbred lines (RILs) derived from a cross between Gemdjah Beton, an Indonesian lowland rice cultivar with soil-surface roots, and Sasanishiki, a Japanese lowland rice cultivar without soil-surface roots. These cultivars and the RILs were tested for soil-surface rooting in a paddy field. We identified four regions of chromosomes 3, 4, 6, and 7 that were associated with soil-surface rooting in the field. Among them, one major QTL was located on the long arm of chromosome 7. This QTL explained 32.5-53.6% of the total phenotypic variance across three field evaluations. To perform fine mapping of this QTL, we measured the basal root growth angle of crown roots at the seedling stage in seven BC(2)F(3) recombinant lines grown in small cups in a greenhouse. The QTL was mapped between markers RM21941 and RM21976, which delimit an 812-kb interval in the reference cultivar Nipponbare. We have designated this QTL qSOR1 (quantitative trait locus for SOIL SURFACE ROOTING 1).

Synergistic Effects of a Calcium Phosphate/Fibronectin Coating on the Adhesion of Periodontal Ligament Stem Cells Onto Decellularized Dental Root Surfaces.

PubMed

Lee, Jung-Seok; Kim, Hyun-Suk; Park, So-Yon; Kim, Tae-Wan; Jung, Jae-Suk; Lee, Jong-Bin; Kim, Chang-Sung

2015-01-01

This study aimed to enhance the attachment of periodontal ligament stem cells (PDLSCs) onto the decellularized dental root surface using surface coating with fibronectin and/or calcium phosphate (CaP) and to evaluate the activity of PDLSCs attached to a coated dental root surface following tooth replantation. PDLSCs were isolated from five dogs, and the other dental roots were used as a scaffold for carrying PDLSCs and then assigned to one of four groups according to whether their surface was coated with CaP, fibronectin, CaP/fibronectin, or left uncoated (control). Fibronectin increased the adhesion of PDLSCs onto dental root surfaces compared to both the control and CaP-coated groups, and simultaneous surface coating with CaP and fibronectin significantly accelerated and increased PDLSC adhesion compared to the fibronectin-only group. On in vivo tooth replantation, functionally oriented periodontal new attachment was observed on the CaP/fibronectin-coated dental roots to which autologous PDLSCs had adhered, while in the control condition, dental root replantation was associated only with root resorption and ankylosis along the entire root length. CaP and fibronectin synergistically enhanced the attachment of PDLSCs onto dental root surfaces, and autologous PDLSCs could produce de novo periodontal new attachment in an experimental in vivo model.

Bioremediation of phenolic compounds from water with plant root surface peroxidases

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

Adler, P.R.; Arora, R.; El Ghaouth, A.

1994-09-01

Peroxidases have been shown to polymerize phenolic compounds, thereby removing them from solution by precipitation. Others have studied the role of root surface associated peroxidases as a defense against fungal root pathogens; however, their use in detoxification of organic pollutants in vivo at the root surface has not been studied. Two plant species, waterhyacinth [Eichhornia crassipes (C. Mart) Solms-Laub.] and tomato (Lycopersicon esculentum L.), were tested for both in vitro and in vivo peroxidase activity on the root surface. In vitro studies indicated that root surface peroxidase activities were 181 and 78 nmol tetraguaiacol formed min{sup -1} g{sup -1} rootmore » fresh wt., for tomato and waterhyacinth, respectively. Light microscope studies revealed that guaiacol was polymerized in vivo at the root surface. Although peroxidase was evenly distributed on tomato roots, it was distributed patchily on waterhyacinth roots. In vitro studies using gas chromatography-mass spectrometry (GC-MS) showed that the efficiency of peroxidase to polymerize phenols vary with phenolic compound. We suggest that plants may be utilized as a source of peroxidases for removal of phenolic compounds that are on the EPA priority pollutant list and that root surface peroxidases may minimize the absorption of phenolic compounds into plants by precipitating them at the root surface. In this study we have identified a new use for root-associated proteins in ecologically engineering plant systems for bioremediation of phenolic compounds in the soil and water environment. 25 refs., 2 figs., 2 tabs.« less

Tyrosinase Inhibitory Activities of Carissa opaca Stapf ex Haines Roots Extracts and Their Phytochemical Analysis

PubMed Central

Malik, Wajeeha; Ahmed, Dildar; Izhar, Sania

2017-01-01

Objective: Carissa opaca is a medicinal plant with rich folkloric applications. The present research was conducted to explore the tyrosinase inhibitory potential of aqueous decoction (AD) and methanolic extract (ME) of roots of C. opaca and its fractions in various solvents and their phytochemical analysis. Materials and Methods: AD of the dried powdered roots of C. opaca was prepared by boiling in water. ME was prepared by cold maceration. Its fractions were obtained in solvents of increasing polarity, i.e., hexane, chloroform, ethyl acetate, n-butanol, and water. The biomass left after extraction with methanol was boiled in water to get its decoction Biomass aqueous decoction (BAD). Tyrosinase inhibitory activities of the samples were studied according to a reported method. Chemical compounds in the samples were identified by gas chromatography-mass spectrometry (GC-MS). Results: The AD, BAD, and ME and its fractions displayed remarkable tyrosinase inhibitory activity. The IC50 of AD was 23.33 μg/mL as compared to 15.80 μg/mL of the standard arbutin and that of BAD was 21.24 μg/mL. The IC50 of ME was 34.76 μg/mL while that of hexane, chloroform, ethyl acetate, n-butanolic, and aqueous fractions was 21.0, 44.73, 43.40, 27.66, and 25.06 μg/mL, respectively. The hexane fraction was thus most potent followed by aqueous fraction. By phytochemical analysis, campesterol, stigmasterol, gamma-sitosterol, alpha-amyrin, 9,19-cyclolanostan-3-ol, 24-methylene-,(3 β)-, lupeol, lup-20(29)-en-3-one, lup-20(29)-en-3-ol, acetate,(3 β)-, 2(1H) naphthalenone, 3,5,6,7,8,8a-hexahydro-4,8a-dimethyl-6-(1-methylethenyl)-, and 2,3,3-trimethyl-2-(3-methylbuta-1,3-dienyl)-6-methylenecyclohexanone were identified in the extracts by GC-MS. Other compounds included fatty acids and their esters. Some of these compounds are being first time reported here from this plant. Conclusions: The roots extracts exhibited considerable tyrosinase inhibitory activities, alluding to a possible application of the plant in cosmetic as whitening agent subject to further pharmacological studies. SUMMARY The present study aimed to explore the tyrosinase inhibitory potential of aqueous decoction and methanolic extract of roots of Carissa opaca and its fractions in various solvents and their phytochemical constituents. GCMS analysis was conducted to identify the phytochemicals. The extracts and fractions of C. opaca roots showed remarkable anti-tyrosinase activities alluding to their possible application to treat disorders related to overproduction of melanin. Abbreviations used: AD: Aqueous decoction; ME: Methanolic extract; BAD: Biomass aqueous decoction; GC-MS: Gas chromatography-mass spectrometry. PMID:29142412

In vitro performance of DIAGNOdent laser fluorescence device for dental calculus detection on human tooth root surfaces.

PubMed

Rams, Thomas E; Alwaqyan, Abdulaziz Y

2017-10-01

This study assessed the reproducibility of a red diode laser device, and its capability to detect dental calculus in vitro on human tooth root surfaces. On each of 50 extracted teeth, a calculus-positive and calculus-free root surface was evaluated by two independent examiners with a low-power indium gallium arsenide phosphide diode laser (DIAGNOdent) fitted with a periodontal probe-like sapphire tip and emitting visible red light at 655 nm wavelength. Laser autofluorescence intensity readings of examined root surfaces were scored on a 0-99 scale, with duplicate assessments performed using the laser probe tip directed both perpendicular and parallel to evaluated tooth root surfaces. Pearson correlation coefficients of untransformed measurements, and kappa analysis of data dichotomized with a >40 autofluorescence intensity threshold, were calculated to assess intra- and inter-examiner reproducibility of the laser device. Mean autofluorescence intensity scores of calculus-positive and calculus-free root surfaces were evaluated with the Student's t -test. Excellent intra- and inter-examiner reproducibility was found for DIAGNOdent laser autofluorescence intensity measurements, with Pearson correlation coefficients above 94%, and kappa values ranging between 0.96 and 1.0, for duplicate readings taken with both laser probe tip orientations. Significantly higher autofluorescence intensity values were measured when the laser probe tip was directed perpendicular, rather than parallel, to tooth root surfaces. However, calculus-positive roots, particularly with calculus in markedly-raised ledges, yielded significantly greater mean DIAGNOdent laser autofluorescence intensity scores than calculus-free surfaces, regardless of probe tip orientation. DIAGNOdent autofluorescence intensity values >40 exhibited a stronger association with calculus (36.6 odds ratio) then measurements of ≥5 (20.1 odds ratio) when the laser probe tip was advanced parallel to root surfaces. Excellent intra- and inter-examiner reproducibility of autofluorescence intensity measurements was obtained with the DIAGNOdent laser fluorescence device on human tooth roots. Calculus-positive root surfaces exhibited significantly greater DIAGNOdent laser autofluorescence than calculus-free tooth roots, even with the laser probe tip directed parallel to root surfaces. These findings provide further in vitro validation of the potential utility of a DIAGNOdent laser fluorescence device for identifying dental calculus on human tooth root surfaces.

Allelopathic potential of Artemisia arborescens: isolation, identification and quantification of phytotoxic compounds through fractionation-guided bioassays.

PubMed

Araniti, Fabrizio; Lupini, Antonio; Sorgonà, Agostino; Conforti, Filomena; Marrelli, Mariangela; Statti, Giancarlo Antonio; Menichini, Francesco; Abenavoli, Maria Rosa

2013-01-01

The aerial part of Artemisia arborescens L. (Asteraceae) was extracted with water and methanol, and both extracts were fractionated using n-hexane, chloroform, ethyl acetate and n-butanol. The potential phytotoxicity of both crude extracts and their fractions were assayed in vitro on seed germination and root growth of lettuce (Lactuca sativa L.), a sensitive species largely employed in the allelopathy studies. The inhibitory activities were analysed by dose-response curves and the ED 50 were estimated. Crude extracts strongly inhibited both germination and root growth processes. The fraction-bioassay indicated the following hierarchy of phytotoxicity for both physiological processes: ethyl acetate ≥ n-hexane > chloroform ≥ n-butanol. On the n-hexane fraction, GC-MS analyses were carried out to characterise and quantify some of the potential allelochemicals. Twenty-one compounds were identified and three of them, camphor, trans-caryophyllene and pulegone were quantified.

Experimental identification of mechanisms controlling calcium isotopic fractionations by the vegetation.

NASA Astrophysics Data System (ADS)

Cobert, Florian; Schimtt, Anne-Désirée.; Bourgeade, Pascale; Stille, Peter; Chabaux, François; Badot, Pierre-Marie; Jaegler, Thomas

2010-05-01

This study aims to better understand the role of vegetation on the Ca cycle at the level of the critical zone of the Earth, in order to specify the mechanisms controlling the Ca absorption by plants at the rock/plant interface. To do this, we performed experiments using hydroponic plant cultures in a way that we could control the co-occuring geochemical and physiological process and determine the impact of the nutritive solution on the Ca cycle within plants. A dicotyledon and calcicole plant with rapid growth, the French bean (Phaseolus vulgaris L.), has been chosen to have access to one complete growth cycle. Several experiments have been conducted with two Ca concentrations, 6 (L) and 60 (H) ppm and two pH values (4 and 6) in the nutritive solution, for which the Ca concentration was maintained constant, so its Ca content is considered as infinite. A second experiment (non infinite L6) allowed Ca depletion in the solution through time; therefore, response effects on the Ca isotopic signatures in the plant organs and in the nutritive solution were observed. We determined Ca concentrations and isotopic ratios in the nutritive solution and in different organs (main roots, secondary roots, old and young stems, old and young leaves and fruits) at two different growth stages (10 days and 6 weeks). Preliminary results show that: (1) the roots (main and secondary) were enriched in the light isotope (40Ca) compared to the nutritive solution, and leaves were enriched in the heavy isotope (44Ca) compared to stems. These results are in accord with previously published field studies (Wigand et al., 2005; Page et al., 2008; Cenki-Tok et al., 2009; Holmden and Bélanger, 2010). Leaves and secondary roots were however enriched in the heavy isotope (44Ca) compared to bean pods, stems and main roots. These results could be related to kinetic fractionation processes occurring either during the Ca root uptake, or during the Ca transport within the plant, or physiological mechanisms occurring first at the level of secondary roots, and second at the level of leaves. (2) No Ca isotope difference was observed neither between old and young organs, (except for H6 leaves), nor between the two growth stages (except for H6 roots). This suggest that the mechanisms controlling isotopic fractionations of Ca within common beans do not vary during growth, and that the nutrients stored in the cotyledons have only a minor effect on the Ca isotope fractionations of plants harvested after 10 days. (3) Strongest Ca isotope fractionations were observed at the nutritive solution/root interface. This implies that the mechanisms of light isotope enrichments in the plant are mainly due to transport processes taking place at this interface. (4) The non infinite L6 nutritive solution became enriched in 44Ca during the experiment compared to the infinite L6 nutritive solution and all the other solutions (L4, H4, and H6). This enrichment can be explained by Rayleigh fractionation or isotopic equilibrium. (5) Bean organs, from L4 and non infinite L6 experiment conditions, were enriched in 44Ca compared to stems and roots cultivated under H4, H6 and infinite L6 conditions. This might be due to the limited Ca in the nutritive solutions that cause smallest Ca isotope fractionations in the bean organs. All these results show that there is no simple correlation between Ca isotopic variations, Ca content and pH of the nutrient solution, and that physiological effects have also to be involved. They confirm the potential of the Ca isotopic system for tracing biological fractionations in natural ecosystems.

Root Surface Bio-modification with Erbium Lasers- A Myth or a Reality??

PubMed Central

Lavu, Vamsi; Sundaram, Subramoniam; Sabarish, Ram; Rao, Suresh Ranga

2015-01-01

The objective of this literature review was to critically review the evidence available in the literature regarding the expediency of erbium family of lasers for root bio modification as a part of periodontal therapy. The literature search was performed on the Pubmed using MeSH words such as "lasers/therapeutic use, scaling, dental calculus, tooth root/anatomy and histology, ultrasonic therapy". The studies were screened and were grouped as follows: those evaluating a) efficacy for calculus removal with the Erbium family of laser b) root surface changes following Er YAG and Er Cr YSGG application c) comparative studies of the Er YAG, Er Cr YSGG lasers versus conventional methods of root surface modification d) Bio compatibility of root surface following Erbium laser treatment e) Studies on the combined efficacy of laser root modification with conventional methods towards root surface bio-modification f) Studies on effectiveness of root surface bio-modification prior to root coverage procedures. In conclusion, the erbium family has a proven anti-bacterial action, predictable calculus removal, minimal root substance removal, and appears to favor cell attachment. The Erbium family of lasers appears to be a useful adjunct for the management of periodontal disease. PMID:25713635

Phytoavailability and mechanism of bound PAH residues in filed contaminated soils.

PubMed

Gao, Yanzheng; Hu, Xiaojie; Zhou, Ziyuan; Zhang, Wei; Wang, Yize; Sun, Bingqing

2017-03-01

Understanding the phytoavailability of bound residues of polycyclic aromatic hydrocarbons (PAHs) in soils is essential to assessing their environmental fate and risks. This study investigated the release and plant uptake of bound PAH residues (reference to parent compounds) in field contaminated soils after the removal of extractable PAH fractions. Plant pot experiments were performed in a greenhouse using ryegrass (Lolium multiflorum Lam.) to examine the phytoavailablility of bound PAH residues, and microcosm incubation experiments with and without the addition of artificial root exudates (AREs) or oxalic acid were conducted to examine the effect of root exudates on the release of bound PAH residues. PAH accumulation in the ryegrass after a 50-day growth period indicated that bound PAH residues were significantly phytoavailable. The extractable fractions, including the desorbing and non-desorbing fractions, dominated the total PAH concentrations in vegetated soils after 50 days, indicating the transfer of bound PAH residues to the extractable fractions. This transfer was facilitated by root exudates. The addition of AREs and oxalic acid to test soils enhanced the release of bound PAH residues into their extractable fractions, resulting in enhanced phytoavailability of bound PAH residues in soils. This study provided important information regarding environmental fate and risks of bound PAH residues in soils. Copyright © 2016 Elsevier Ltd. All rights reserved.

Carbon isotope fractionation in the mangrove Avicennia marina has implications for food web and blue carbon research

NASA Astrophysics Data System (ADS)

Kelleway, Jeffrey J.; Mazumder, Debashish; Baldock, Jeffrey A.; Saintilan, Neil

2018-05-01

The ratio of stable isotopes of carbon (δ13C) is commonly used to track the flow of energy among individuals and ecosystems, including in mangrove forests. Effective use of this technique requires understanding of the spatial variability in δ13C among primary producer(s) as well as quantification of the isotopic fractionations that occur as C moves within and among ecosystem components. In this experiment, we assessed δ13C variation in the cosmopolitan mangrove Avicennia marina across four sites of varying physico-chemical conditions across two estuaries. We also compared the isotopic values of five distinct tissue types (leaves, woody stems, cable roots, pneumatophores and fine roots) in individual plants. We found a significant site effect (F3, 36 = 15.78; P < 0.001) with mean leaf δ13C values 2.0‰ more depleted at the lowest salinity site compared to the other locations. There was a larger within-plant fractionation effect, however, with leaf samples (mean ± SE = -29.1 ± 0.2) more depleted in 13C than stem samples (-27.1 ± 0.1), while cable root (-25. 8 ± 0.1), pneumatophores (-25.7 ± 0.1) and fine roots (-26.0 ± 0.2) were more enriched in 13C relative to both aboveground tissue types (F4, 36 = 223.45; P < 0.001). The within-plant δ13C fractionation we report for A. marina is greater than that reported in most other ecosystems. This has implications for studies of estuarine carbon cycling. The consistent and large size of the fractionation from leaf to woody stem (∼2.0‰) and mostly consistent fractionation from leaf to root tissues (>3.0‰) means that it may now be possible to partition the individual contributions of various mangrove tissues to estuarine food webs. Similarly, the contributions of mangrove leaves, woody debris and belowground sources to blue carbon stocks might also be quantified. Above all, however, our results emphasize the importance of considering appropriate mangrove tissue types when using δ13C to trace carbon cycling in estuarine systems.

Impact of cadmium stress on two maize hybrids.

PubMed

Vatehová, Zuzana; Malovíková, Anna; Kollárová, Karin; Kučerová, Danica; Lišková, Desana

2016-11-01

Some physiological parameters and composition of the root cell walls of two maize hybrids (monocots), the sensitive Novania and the tolerant Almansa were studied after treatment with cadmium cations. After 10 days of Cd 2+ treatment (1 × 10 -5  M and 5 × 10 -5  M), plant growth inhibition, in the sensitive hybrid in particular, as well as a certain alteration in root structure and pigment content were observed. The Cd 2+ accumulation was ten times higher in the roots than in the shoots. Chemical analyses and atomic absorption spectroscopy proved that Cd 2+ modified the composition of the root cell walls by a significant increase in the content of alkali-soluble polysaccharide fractions, particularly in the tolerant hybrid. An increase in the content of phenolic compounds, mainly in the tolerant hybrid, and a decrease in protein content were observed in the presence of Cd 2+ in the alkali fractions. The results indicate that the changes in the cell wall polysaccharide fractions and their proportion to lignin and cellulose are obviously involved in the tolerance and/or defence against Cd 2+ of the maize hybrids studied. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Cell wall-bound cationic and anionic class III isoperoxidases of pea root: biochemical characterization and function in root growth.

PubMed

Kukavica, Biljana M; Veljovicc-Jovanovicc, Sonja D; Menckhoff, Ljiljana; Lüthje, Sabine

2012-07-01

Cell wall isolated from pea roots was used to separate and characterize two fractions possessing class III peroxidase activity: (i) ionically bound proteins and (ii) covalently bound proteins. Modified SDS-PAGE separated peroxidase isoforms by their apparent molecular weights: four bands of 56, 46, 44, and 41kDa were found in the ionically bound fraction (iPOD) and one band (70kDa) was resolved after treatment of the cell wall with cellulase and pectinase (cPOD). Isoelectric focusing (IEF) patterns for iPODs and cPODs were significantly different: five iPODs with highly cationic pI (9.5-9.2) were detected, whereas the nine cPODs were anionic with pI values between pH 3.7 and 5. iPODs and cPODs showed rather specific substrate affinity and different sensitivity to inhibitors, heat, and deglycosylation treatments. Peroxidase and oxidase activities and their IEF patterns for both fractions were determined in different zones along the root and in roots of different ages. New iPODs with pI 9.34 and 9.5 were induced with root growth, while the activity of cPODs was more related to the formation of the cell wall in non-elongating tissue. Treatment with auxin that inhibits root growth led to suppression of iPOD and induction of cPOD. A similar effect was obtained with the widely used elicitor, chitosan, which also induced cPODs with pI 5.3 and 5.7, which may be specifically related to pathogen defence. The differences reported here between biochemical properties of cPOD and iPOD and their differential induction during development and under specific treatments implicate that they are involved in specific and different physiological processes.

Phytoremediation in the tropics--influence of heavy crude oil on root morphological characteristics of graminoids.

PubMed

Merkl, Nicole; Schultze-Kraft, Rainer; Infante, Carmen

2005-11-01

When studying species for phytoremediation of petroleum-contaminated soils, one of the main traits is the root zone where enhanced petroleum degradation takes place. Root morphological characteristics of three tropical graminoids were studied. Specific root length (SRL), surface area, volume and average root diameter (ARD) of plants grown in crude oil-contaminated and uncontaminated soil were compared. Brachiaria brizantha and Cyperus aggregatus showed coarser roots in polluted soil compared to the control as expressed in an increased ARD. B. brizantha had a significantly larger specific root surface area in contaminated soil. Additionally, a shift of SRL and surface area per diameter class towards higher diameters was found. Oil contamination also caused a significantly smaller SRL and surface area in the finest diameter class of C. aggregatus. The root structure of Eleusine indica was not significantly affected by crude oil. Higher specific root surface area was related to higher degradation of petroleum hydrocarbons found in previous studies.

Systematic review finds that silver diamine fluoride is effective for both root caries prevention and arrest in older adults.

PubMed

McReynolds, David; Duane, Brett

2018-06-01

Data sourcesPubMed, Pubmed Clinical Queries, EMBASE, the American Dental Associations Evidence-Based Dentistry Website, Cochrane Library, Web of Science, repository of the Journal of the American Dental Association and Google Scholar.Study selectionFour authors independently assessed the abstracts of studies resulting from the above searches which compared treatment of root caries in an older population with SDF versus other preventive agents or placebos.Data extraction and synthesisTitles and abstracts of all reports identified through the electronic searches were assessed independently by four authors based on agreed upon inclusion and exclusion criteria. Of the selected studies for final inclusion in the systematic review, study quality was assessed using the critical appraisal worksheet for randomised controlled trials from the Oxford Centre for Evidence-Based Medicine (CEBM 2005). Prevented fraction (PF), number needed to treat (NNT) and relative risk (RR) were calculated as outcome measures in each study. In addition, the published evidence on SDF was reviewed in order to formulate clinical recommendations on safety and effectiveness when treating root or coronal caries in an adult population with SDF, as well as treatment of dental hypersensitivity.ResultsThree randomised controlled trials were identified that addressed the effectiveness of SDF on root caries in older adults, but none addressed coronal caries. Root caries prevented fraction and arrest rate for SDF were significantly higher than placebo. The prevented fraction for caries prevention for SDF compared to placebo was 71% in a three-year study and 25% in a two-year study. The prevented fraction for caries arrest for SDF was 725% greater in a 24-month study and 100% greater than placebo in a 30-month study. No severe adverse effects were observed.ConclusionsExisting reports of SDF trials support effectiveness in root caries prevention and arrest, remineralisation of deep occlusal lesions and treatment of hypersensitive dentine.

Plastic responses of native plant root systems to the presence of an invasive annual grass.

PubMed

Phillips, Allison J; Leger, Elizabeth A

2015-01-01

• The ability to respond to environmental change via phenotypic plasticity may be important for plants experiencing disturbances such as climate change and plant invasion. Responding to belowground competition through root plasticity may allow native plants to persist in highly invaded systems such as the cold deserts of the Intermountain West, USA.• We investigated whether Poa secunda, a native bunchgrass, could alter root morphology in response to nutrient availability and the presence of a competitive annual grass. Seeds from 20 families were grown with high and low nutrients and harvested after 50 d, and seeds from 48 families, grown with and without Bromus tectorum, were harvested after ∼2 or 6 mo. We measured total biomass, root mass fraction, specific root length (SRL), root tips, allocation to roots of varying diameter, and plasticity in allocation.• Plants had many parallel responses to low nutrients and competition, including increased root tip production, a trait associated with tolerance to reduced resources, though families differed in almost every trait and correlations among trait changes varied among experiments, indicating flexibility in plant responses. Seedlings actively increased SRL and fine root allocation under competition, while older seedlings also increased coarse root allocation, a trait associated with increased tolerance, and increased root mass fraction.• The high degree of genetic variation for root plasticity within natural populations could aid in the long-term persistence of P. secunda because phenotypic plasticity may allow native species to persist in invaded and fluctuating resource environments. © 2015 Botanical Society of America, Inc.

Measurement of surface microtopography

NASA Technical Reports Server (NTRS)

Wall, S. D.; Farr, T. G.; Muller, J.-P.; Lewis, P.; Leberl, F. W.

1991-01-01

Acquisition of ground truth data for use in microwave interaction modeling requires measurement of surface roughness sampled at intervals comparable to a fraction of the microwave wavelength and extensive enough to adequately represent the statistics of a surface unit. Sub-centimetric measurement accuracy is thus required over large areas, and existing techniques are usually inadequate. A technique is discussed for acquiring the necessary photogrammetric data using twin film cameras mounted on a helicopter. In an attempt to eliminate tedious data reduction, an automated technique was applied to the helicopter photographs, and results were compared to those produced by conventional stereogrammetry. Derived root-mean-square (RMS) roughness for the same stereo-pair was 7.5 cm for the automated technique versus 6.5 cm for the manual method. The principal source of error is probably due to vegetation in the scene, which affects the automated technique but is ignored by a human operator.

Micronucleus induction in Vicia faba roots. Part 1. Absence of dose-rate, fractionation, and oxygen effect at low doses of low LET radiations.

PubMed

Marshall, I; Bianchi, M

1983-08-01

Micronucleus indication in Vicia faba roots has been evaluated after irradiation with 60Co gamma-rays. The dependence of the damage on dose, dose rate, fractionation, and oxygen has been studied. The best fit to the experimental data in the dose region between 7 and 190 cGy is represented, for single-dose exposures, by a linear + quadratic relationship. In the low-dose region, between 7 and 20 cGy, where the linear dose dependence is dominant, no dose-rate, fractionation, or oxygen effect could be observed. These effects were, however, present in the high-dose region, where the quadratic dependence is dominant.

Bioactivity-guided fractionation for the butyrylcholinesterase inhibitory activity of furanocoumarins from Angelica archangelica L. roots and fruits.

PubMed

Wszelaki, Natalia; Paradowska, Katarzyna; Jamróz, Marta K; Granica, Sebastian; Kiss, Anna K

2011-09-14

Isolation and identification of the inhibitors of butyrylcholinesterase (BChE), obtained from the extracts of roots and fruits of Angelica archangelica L., are reported. Our results confirmed the weak inhibitory effect of Angelica roots on acetylcholinesterase activity. BChE inhibition was much more pronounced at a concentration of 100 μg/mL for hexane extracts and attained a higher rate than 50%. The TLC bioautography guided fractionation and spectroscopic analysis led to the isolation and identification of imperatorin from the fruit's hexane extract and of heraclenol-2'-O-angelate from the root's hexane extract. Both compounds showed significant BChE inhibition activity with IC(50) = 14.4 ± 3.2 μM and IC(50) = 7.5 ± 1.8 μM, respectively. Only C8-substituted and C5-unsubstituted furanocoumarins were active, which could supply information about the initial structures of specific BChE inhibitors.

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

Bony, Sandrine; Stevens, Bjorn; Coppin, David

General circulation models show that as the surface temperature increases, the convective anvil clouds shrink. By analyzing radiative–convective equilibrium simulations, our work shows that this behavior is rooted in basic energetic and thermodynamic properties of the atmosphere: As the climate warms, the clouds rise and remain at nearly the same temperature, but find themselves in a more stable atmosphere; this enhanced stability reduces the convective outflow in the upper troposphere and decreases the anvil cloud fraction. By warming the troposphere and increasing the upper-tropospheric stability, the clustering of deep convection also reduces the convective outflow and the anvil cloud fraction.more » When clouds are radiatively active, this robust coupling between temperature, high clouds, and circulation exerts a positive feedback on convective aggregation and favors the maintenance of strongly aggregated atmospheric states at high temperatures. This stability iris mechanism likely contributes to the narrowing of rainy areas as the climate warms. Whether or not it influences climate sensitivity requires further investigation.« less

Isolation and characterization of bioactive polyacetylenes Panax ginseng Meyer roots.

PubMed

Yeo, Chia-Rou; Yong, Jin-Jie; Popovich, David G

2017-05-30

Panax ginseng has been studied for its chemo-preventive properties and pharmaceutical potential. Polyacetylenic compounds isolated from Panax ginseng root typically comprised of non-polar C 17 compound have been reported to exhibit bioactive properties. The objective of this project is to extract, isolate, and characterize bioactive polyacetylenes from Panax ginseng root using various extraction and separation methods Ginseng was extracted by reflux using methanol, ethanol, hexane, ethyl acetate, methanolic ultrasonication. The extracts were partitioned with hexane to obtain water-soluble portion and hexane-soluble portion. Hexane was subsequently removed under vacuum, and formed a crude polyacetylenes extract (crude PA). Silica gel chromatography and semi-preparative HPLC were utilized to prepare 5 fractions and the polyacetylenes were measure by HPLC and molecular weights confirm my APCI-MS and MNR. The bioactive effect was measured by MTT viability assay using murine 3T3-L1 cells. Extraction with methanol under reflux produced significantly larger amount of polyacetylenes (p<0.05). Liquid-liquid extraction and column chromatography were used to separate polyacetylenic compounds into five different fractions. Major polyacetylenes, panaxynol and panaxydol were found in fraction 1 and 2 respectively. Dose-response relationships were observed in 3T3-L1 cells and LC50 were 13.52±3.05μg/mL (fraction 1), 3.69±1.09μg/mL (fraction 2), 52.88±11.16μg/mL (fraction 3), 85.91±27.37μg/mL (fraction 4) and 135.52±32.91μg/mL (fraction 5). Fraction 2 containing panaxydol was found to have exhibited the greatest anti-proliferative effects on 3T3-L1 preadipocytes. Extraction with methanol under reflux produced significantly more polyacetylenes. Fractions that contain panaxydol was the most cytotoxic. Copyright © 2017 Elsevier B.V. All rights reserved.

Essential oils chemical composition, antioxidant activities and total phenols of Astrodaucus persicus.

PubMed

Goodarzi, Saeid; Hadjiakhoondi, Abbas; Yassa, Narguess; Khanavi, Mahnaz; Tofighi, Zahra

2016-02-01

Astrodaucus persicus, Apiaceae, is used as vegetable or food additive in some parts of Iran. The essential oils of different parts of Astrodaucus persicus from Kordestan province were analyzed for the first time and compared with other regions. In this study, antioxidant activities and total phenols determination of aerial parts essential oils and root fractions of A. persicus were investigated. The essential oils were obtained by hydro-distillation from flowers/fruits, leaves/stems, ripe fruits and roots of plant and analyzed by GC-MS. Crude root extract was fractionated with hexane, chloroform, ethyl acetate and methanol. Antioxidant activities by DPPH and FRAP methods and total phenols by Folin-ciocalteu assay were measured. The abundant compounds of flowers/fruits blue essential oil were α-thujene, β-pinene and α-pinene. The predominant components of blue leaves/stems essential oil were α-thujene, α-pinene and α-fenchene. The major volatiles of ripe fruits blue essential oil were β-pinene, α-thujene and α-pinene. The chief compounds of root yellow essential oil were trans-caryophyllene, bicycogermacrene and germacrene-D. Total root extract and ethyl acetate fraction showed potent antioxidant activities and high amount of total phenols in comparison to other samples. Among volatile oils, the flowers/fruits essential oil showed potent reducing capacity. The major compounds of aerial parts essential oils were hydrocarbon monoterpenes while the chief percentage of roots essential oil constituents were hydrocarbon sesquiterpenes. α-Eudesmol and β-eudesmol were identified as responsible for creation of blue color in aerial parts essential oils. A. persicus was known as a potent antioxidant among Apiaceae.

Comparison of cadmium absorption, translocation, subcellular distribution and chemical forms between two radish cultivars (Raphanus sativus L.).

PubMed

Xin, Juan; Zhao, Xiaohu; Tan, Qiling; Sun, Xuecheng; Hu, Chengxiao

2017-11-01

Cadmium (Cd) absorption and accumulation vary greatly not only among plant species but also among cultivars within the same species. In order to better understand the mechanisms of Cd absorption, transportation and distribution, we examined the differences of Cd absorption, translocation, subcellular distribution and chemical forms between L19, a Cd-tolerant genotype, and H4, a Cd-sensitive genotype, using kinetic analysis and soil culture experiment. Kinetic assays showed that the different Cd concentrations between the two cultivars might be ascribed to root absorption and translocation from root to shoot. The investigations of subcellular distribution and chemical forms verified that Cd concentrations of all subcellular fractions in H4 were all higher than in L19. Meanwhile, most of the Cd was associated with cell walls in the root of H4, but the Cd in the root of L19 and leaf of the two cultivars was mainly stored in soluble fraction, which could be one possible mechanism of tolerance to Cd toxicity. In addition, Cd fractions extracted by 1M NaCl and 2% HAC were predominant in root and leaf of both cultivars and the concentrations and proportions extracted by water and 80% ethanol in root and 1M NaCl in leaf were all higher in H4 than in L19. These results indicate that the Cd in H4 is more active than L19, which could be responsible for the sensitivity of H4 to Cd damage. Copyright © 2017 Elsevier Inc. All rights reserved.

Root surface removal and resultant surface texture with diamond-coated ultrasonic inserts: an in vitro and SEM study.

PubMed

Vastardis, Sotirios; Yukna, Raymond A; Rice, David A; Mercante, Don

2005-05-01

A new diamond-coated ultrasonic insert has been developed for scaling and root planing, and it was evaluated in vitro for the amount of root surface removed and the roughness of the residual root surface as a result of instrumentation. 48 extracted single-rooted human teeth were ground flat on one root surface and mounted (flat side up) in PVC rings of standard height and diameter with improved dental stone. Each tooth surface was treated with either a plain ultrasonic insert (PI), an ultrasonic insert with a fine grit diamond coating (DI) or sharp Gracey curettes (HI). The mounted teeth were attached to a stepper motor which drove the teeth in a horizontal, reciprocal motion at a constant rate. The thickness from the flattened bottom of the ring to the flattened tooth surface was measured before and after 10, 20, and 30 instrumentation strokes for each root surface with each of the experimental instruments. A number of treated teeth were randomly selected for examination with SEM and a profilometer. Statistical analysis (analysis of co-variance) was performed to compare the amounts of tooth structure removed among the 3 instruments and t-test was used to compare the roughness of the treated root surfaces. The mean depth of root structure removed was PI 10.7 microm, HI 15.0 microm, and DI 46.2 microm after 10 strokes; and PI 21.6 microm, HI 33.2 and DI 142.0 microm after 30 strokes, respectively. On average, 0.9 microm, 1.3 microm, and 4.7 microm of root surface was removed with each stroke of PI, HI and DI, respectively. PI and HI were not different from each other for all the stroke cycles, while DI was significantly different from PI and HI for all the stroke cycles (p<0.0001). Analysis with the profilometer showed that the smoothest surface was produced by the PI followed by the HI. The DI produced a surface that was significantly rougher than the surface produced by the PI or HI. These results suggest that diamond-coated ultrasonic instruments will effectively plane roots, and that caution should be used during periodontal root planing procedures. Additionally, the diamond-coated instruments will produce a rougher surface than the plain inserts or the hand curettes.

Optimal partitioning theory revisited: nonstructural carbohydrates dominate root mass responses to nitrogen.

PubMed

Kobe, Richard K; Iyer, Meera; Walters, Michael B

2010-01-01

Under optimal partitioning theory (OPT), plants preferentially allocate biomass to acquire the resource that most limits growth. Within this framework, higher root mass under low nutrients is often assumed to reflect an allocation response to build more absorptive surface. However, higher root mass also could result from increased storage of total nonstructural carbohydrates (TNC) without an increase in non-storage mass or root surface area. To test the relative contributions of TNC and non-storage mass as components of root mass responses to resources, we grew seedlings of seven northern hardwood tree species (black, red, and white oak, sugar and red maple, American beech, and black cherry) in a factorial light x nitrogen (N) greenhouse experiment. Because root mass is a coarse metric of absorptive surface, we also examined treatment effects on fine-root surface area (FRSA). Consistent with OPT, total root mass as a proportion of whole-plant mass generally was greater in low vs. high N. However, changes in root mass were influenced by TNC mass in all seven species and were especially strong in the three oak species. In contrast, non-storage mass contributed to increased total root mass under low N in three of the seven species. Root morphology also responded, with higher fine-root surface area (normalized to root mass) under low vs. high N in four species. Although biomass partitioning responses to resources were consistent with OPT, our results challenge the implicit assumption that increases in root mass under low nutrient levels primarily reflect allocation shifts to build more root surface area. Rather, root responses to low N included increases in: TNC, non-storage mass and fine-root surface area, with increases in TNC being the largest and most consistent of these responses. The greatest TNC accumulation occurred when C was abundant relative to N. Total nonstructural carbohydrates storage could provide seedlings a carbon buffer when respiratory or growth demands are not synchronized with photosynthesis, flexibility in responding to uncertain and fluctuating abiotic and biotic conditions, and increased access to soil resources by providing an energy source for mycorrhizae, decomposers in the rhizosphere, or root uptake of nutrients.

Cell-cell recognition of host surfaces by pathogens. The adsorption of maize (Zea mays) root mucilage by surfaces of pathogenic fungi.

PubMed Central

Gould, J; Northcote, D H

1986-01-01

The adsorption of radioactive mucilage by pathogenic fungi was shown to be dependent upon time, the composition of mucilage, the type of fungal surface (conidia, hyphae, hyphal apices), fungal species, pH and bivalent cations. All fungal adhesins were inactivated by either proteinase or polysaccharase treatments. Adsorption was not inhibited by the numberous mono-, di- and oligo-saccharides that were tested individually, but it was inhibited absolutely by several polysaccharides. This suggested that adsorption of mucilage by pathogens involved conformational and ionic interactions between plant and fungal polymers but not fungal lectins bound to sugar residues of mucilage. Several fractionation schemes showed that pathogens bound only the most acidic of the variety of polymers that comprise mucilage. There was not any absolute distinction between ability to bind radioactive mucilage and type of pathogen or non-pathogen. However, there were notable differences in characteristics of adsorption between two types of pathogen. Differences were revealed by comparison of the adsorption capacities of conidia and germinant conidia and chromatography of radioactive mucilage on germinant conidia. An ectotrophic root-infecting fungus (a highly specialized pathogen) bound a greater proportion of mucilage than did a vascular-wilt fungus (of catholic host and tissue range) with more than one class of site for adsorption. In contrast with the vascular-wilt fungus, sites for adsorption on the specialized pathogen were present solely on surfaces formed by germination. PMID:3954742

Central depressant activity of butanol fraction of Securinega virosa root bark in mice.

PubMed

Magaji, Mohammed Garba; Yaro, Abdullahi Hamza; Musa, Aliyu Muhammad; Anuka, Joseph Akponso; Abdu-Aguye, Ibrahim; Hussaini, Isa Marte

2012-05-07

Securinega virosa is a commonly used medicinal plant in African traditional medicine in the management of epilepsy and mental illness. Previous studies in our laboratory showed that the crude methanol root bark extract of the plant possesses significant behavioral effect in laboratory animals. In an attempt to isolate and characterize the biological principles responsible for the observed activity, this study is aimed at evaluating the central depressant activity of the butanol fraction of the methanol root bark extract of Securinega virosa. The medial lethal dose of the butanol fraction was estimated using the method of Lorke. Preliminary phytochemical screening was conducted on the butanol fraction using standard protocol. The behavioral effect of the butanol fraction (75, 150 and 300mg/kg) was evaluated using diazepam induced sleep test, hole-board test, beam walking assay, staircase test, open field test and elevated plus maze assay, all in mice. The median lethal dose of the butanol fraction was estimated to be 1256.9mg/kg. The preliminary phytochemical screening revealed the presence of tannins, saponins, alkaloids, flavonoids, cardiac glycosides, similar to those found in the crude methanol extract. The butanol fraction significantly (P<0.001) reduced the mean onset of sleep in mice and doubled the mean duration of sleep in mice at the dose of 75mg/kg. The butanol fraction and diazepam (0.5mg/kg) significantly (P<0.01-0.001) reduced the number of head dips in the hole-board test suggesting sedative effect. The sedative effect of the butanol fraction was further corroborated by its significant (P<0.01-0.001) reduction of the number of step climbed and rearing in the staircase test. The butanol fraction did not significantly increase the time taken to complete the task and number of foot slips in the beam walking assay, suggesting that it does not induce significant motor coordination deficit. Diazepam (2mg/kg), the standard agent used significantly (P<0.01) increased the number of foot slips. In the open field test, the butanol fraction significantly reduced the number of square crossed as well as the number of rearing. However, the butanol fraction did not significantly alter the behavior of mice in the elevated plus maze assay, while diazepam (0.5mg/kg) significantly (P<0.05) increased the time spent in the open arm and reduced the number of closed arm entry. The findings of this study suggest that the butanol fraction of Securinega virosa root bark contains some bioactive principles that are sedative in nature. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Transport, ultrastructural localization, and distribution of chemical forms of lead in radish (Raphanus sativus L.).

PubMed

Wang, Yan; Shen, Hong; Xu, Liang; Zhu, Xianwen; Li, Chao; Zhang, Wei; Xie, Yang; Gong, Yiqin; Liu, Liwang

2015-01-01

Lead (Pb), a ubiquitous but highly toxic heavy metal (HM), is harmful to human health through various pathways including by ingestion of contaminated vegetables. Radish is a worldwide root vegetable crop with significant health and nutritional benefits. However, little is known about Pb translocation and distribution within radish plants after its uptake by the roots. In this study, Pb stress was induced using Pb(NO3)2 in hydroponic culture, aiming to characterize the transport, ultrastructural localization, and distribution of chemical forms of Pb in different tissues of radish. The results showed that the majority of Pb (85.76-98.72%) was retained in underground organs including lateral roots, root heads and taproot skins, while a small proportion of Pb was absorbed by root flesh (0.44-1.56%) or transported to the shoot (1.28-14.24%). A large proportion of Pb (74.11-99.30%) was integrated with undissolved Pb oxalate, protein and pectates forming Pb-phosphate complexes. Moreover, a low-Pb-accumulating line of radish showed a higher proportion of Pb in water-soluble form compared with a high-Pb-accumulating line. Subcellular distribution analysis showed that a large proportion of Pb was bound to cell wall fraction in lateral roots (71.08-80.40%) and taproot skin (46.22-77.94%), while the leaves and roots had 28.36-39.37% and 27.35-46.51% of Pb stored in the soluble fraction, respectively. Furthermore, transmission electron microscopy (TEM) revealed Pb precipitates in intercellular space, cell wall, plasma lemma and vacuoles. Fractionation results also showed the accumulation of Pb on the cell wall, intercellular space and vacuole, and low uptake of undissolved Pb oxalate, protein, pectates and Pb-phosphate complexes, which might be due to low transport efficiency and Pb tolerance of radish. These findings would provide insight into molecular mechanism of Pb uptake and translocation in radish and facilitate development of low-Pb-content cultivars in root vegetable crops.

Relationship of cariogenic bacteria levels with periodontal status and root surface caries in elderly Japanese.

PubMed

Saotome, Yasuhiko; Tada, Akio; Hanada, Nobuhiro; Yoshihara, Akihiro; Uematsu, Hiroshi; Miyazaki, Hideo; Senpuku, Hidenobu

2006-12-01

The relationship of the levels of cariogenic bacterial species with periodontal status and decayed root surfaces was investigated in elderly Japanese subjects. Three hundred and sixty-eight individuals (each 75 years old) were examined for periodontal status (pocket depth, attachment loss), root surface caries and salivary levels of mutans streptococci (MS) and lactobacilli (LB). Values >4 mm of attachment loss (rAL4) and for average attachment loss (aAL) of sites measured were significantly higher in subjects with LB than those without. Multiple regression analysis also showed a correlation between aAL and rAL4 values with the presence of LB (aAL p = 0.003; rAL4 p = 0.002). Further, multiple regression analysis of interacting factors regarding decayed root surfaces showed that LB carriers had a greater incidence of decayed root surface caries (p = 0.003), while MS and LB levels were correlated to the number of decayed root surfaces (LB p = 0.010; MS p = 0.026). Our results indicate that considerable attachment loss elevates the possibility of having LB, thus increasing the risk of root surface caries. It was also found that LB and MS measurements may be useful indicators of decayed root surfaces in elderly individuals with attachment loss.

Free radical scavenging, antidiarrheal and anthelmintic activity of Pistia stratiotes L. extracts and its phytochemical analysis.

PubMed

Bin Karim, Mohammed Faisal; Imam, Hasan; Sarker, Md Moklesur-Rahman; Uddin, Nizam; Hasan, Nahid; Paul, Nirmala; Haque, Tahmina

2015-05-01

In this phyto-pharmacological screening of Pistia stratiotes L leaf and root extracts each separately in two different solvents demonstrated its potential medicinal value. Apparent antioxidant value is demonstrated by DPPH, Nitric oxide scavenging and Ferric ion reducing method. Additionally, total flavonoid and phenolic compounds were measured. The leaf methanolic extract scavenged both nitric oxide (NO) and DPPH radical with a dose dependent manner. But the pet ether fraction of root was found to have highest efficacy in Fe(3±) reducing power assay. Flavonoid was found to contain highest in the pet ether fraction of root (411.35mg/g) in terms of quercetin equivalent, similarly highest amount (34.96mg/g) of total phenolic compounds (assayed as gallic acid equivalents) were found to contain in the same fraction. The methanolic fractions appeared less cytotoxic compared to pet ether extracts. The plant extracts caused a dose dependent decrease in faecal droppings in both castor oil and magnesium sulphate induced diarrhea, where as leaf extracts in each solvent appeared most effective. Also, the plant extracts showed anthelmintic activity in earthworm by inducing paralysis and death in a dose dependent manner. At highest doses (50 mg/ml) all fractions were almost effective as the positive control piperazine citrate (10 mg/ml). Thus, besides this cytotoxic effect it's traditional claim for therapeutic use can never be overlooked.

The effect of ultrasonic post instrumentation on root surface temperature.

PubMed

Huttula, Andrew S; Tordik, Patricia A; Imamura, Glen; Eichmiller, Frederick C; McClanahan, Scott B

2006-11-01

This study measured root surface temperature changes when ultrasonic vibration, with and without irrigation, was applied to cemented endodontic posts. Twenty-six, extracted, single-rooted premolars were randomly divided into two groups. Root lengths were standardized, canals instrumented, obturated, and posts cemented into prepared spaces. Thermocouples were positioned at two locations on the proximal root surfaces. Samples were embedded in plaster and brought to 37 degrees C in a water bath. Posts were ultrasonically vibrated for 4 minutes while continuously measuring temperature. Two-way ANOVA compared effects of water coolant and thermocouple location on temperature change. Root surface temperatures were significantly higher (p < 0.001) when posts were instrumented dry. A trend for higher temperatures was observed at coronal thermocouples of nonirrigated teeth and at apical thermocouples of irrigated teeth (p = 0.057). Irrigation during post removal with ultrasonics had a significant impact on the temperature measured at the external root surface.

Insecticidal compounds from Rhizophoraceae mangrove plants for the management of dengue vector Aedes aegypti.

PubMed

Ali, M Syed; Ravikumar, S; Beula, J Margaret; Anuradha, V; Yogananth, N

2014-06-01

Mosquito control is facing a threat due to the emergence of resistance to synthetic insecticides. Insecticides of botanical origin could serve as potential alternatives in future. Larvicidal efficacies of different parts of mangrove plants belonging to Rhizophoraceae family were tested against the late IV instar larvae of dengue vector, Aedes aegypti. Different plant parts (leaf, bark, root, stilt root, hypocotyl and flower) of Rhizophoraceae family mangrove plants (Bruguiera cylindrica, Ceriops decandra, Rhizophora mucronata and R. apiculata) were collected from Karangadu southeast coast of India. The larval mortality was observed after 24 h exposure. Repellency bioassays were carried out in a 10 Χ 10 Χ 3 m room at 27- 35°C and 60- 80% RH. The bark (A3 and E1) and stilt root (A3 and E4) fractions of R. mucronata with different concentrations (0.25, 0.50, 0.75, 1, 2 and 4 mg/cm) were applied on one arm. The stilt root crude extract of R. mucronata showed maximum larvicidal activity (LC50 value 0.0275 ± 0.0066 μg/ml and LC90 = 0.0695 ± 0.156 μg/ml) followed by the bark extract (LC50 value of 0.03 ± 0.0076 μg/ml and LC90 = 0.0915 ± 0.156 μg/ml). Column chromatographic fractions of R. mucronata bark extracts (E1) showed maximum larvicidal activity (LC50 = 0.0496 ± 0.0085 μg/ml and LC90 = 0.1264 ± 0.052 μg/ml) followed by the acetone extract (LC50 = 0.0564 ± 0.0069 μg/ml and LC90 = 0.1187 ± 0.05 μg/ml). Ethanolic fraction (E4) of R. mucronata stilt root extracts showed maximum larvicidal activity (LC50 = 0.0484 ± 0.0078 μg/ml and LC90 = 0.1191 ± 0.025 μg/ml) followed by acetone fraction (A3) (LC50 = 0.0419 ± 0.0059 μg/ml and LC90 = 0.0955 ± 0.069 μg/ml). Repellent activity of R. mucronata stilt root and bark extracts (A3) showed maximum percentage of protection (97.5%) with 9.1 h protection time at 4 mg concentration of the stilt root extract. Moreover, ethanolic fraction of the stilt root (E4) extract showed maximum percentage of protection (100%) with 10 h protection time at 4 mg concentration. GC-MS analysis revealed that R. mucronata possesses variety of biopesticidal compounds. The results as well as the significance of this preliminary investigation highlight the importance of R. mucronata as a novel source for natural insecticidal products.

Advances in the simulation and automated measurement of well-sorted granular material: 2. Direct measures of particle properties

USGS Publications Warehouse

Buscombe, Daniel D.; Rubin, David M.

2012-01-01

1. In this, the second of a pair of papers on the structure of well-sorted natural granular material (sediment), new methods are described for automated measurements from images of sediment, of: 1) particle-size standard deviation (arithmetic sorting) with and without apparent void fraction; and 2) mean particle size in material with void fraction. A variety of simulations of granular material are used for testing purposes, in addition to images of natural sediment. Simulations are also used to establish that the effects on automated particle sizing of grains visible through the interstices of the grains at the very surface of a granular material continue to a depth of approximately 4 grain diameters and that this is independent of mean particle size. Ensemble root-mean squared error between observed and estimated arithmetic sorting coefficients for 262 images of natural silts, sands and gravels (drawn from 8 populations) is 31%, which reduces to 27% if adjusted for bias (slope correction between observed and estimated values). These methods allow non-intrusive and fully automated measurements of surfaces of unconsolidated granular material. With no tunable parameters or empirically derived coefficients, they should be broadly universal in appropriate applications. However, empirical corrections may need to be applied for the most accurate results. Finally, analytical formulas are derived for the one-step pore-particle transition probability matrix, estimated from the image's autocorrelogram, from which void fraction of a section of granular material can be estimated directly. This model gives excellent predictions of bulk void fraction yet imperfect predictions of pore-particle transitions.

Advances in the simulation and automated measurement of well-sorted granular material: 2. Direct measures of particle properties

NASA Astrophysics Data System (ADS)

Buscombe, D.; Rubin, D. M.

2012-06-01

In this, the second of a pair of papers on the structure of well-sorted natural granular material (sediment), new methods are described for automated measurements from images of sediment, of: 1) particle-size standard deviation (arithmetic sorting) with and without apparent void fraction; and 2) mean particle size in material with void fraction. A variety of simulations of granular material are used for testing purposes, in addition to images of natural sediment. Simulations are also used to establish that the effects on automated particle sizing of grains visible through the interstices of the grains at the very surface of a granular material continue to a depth of approximately 4 grain diameters and that this is independent of mean particle size. Ensemble root-mean squared error between observed and estimated arithmetic sorting coefficients for 262 images of natural silts, sands and gravels (drawn from 8 populations) is 31%, which reduces to 27% if adjusted for bias (slope correction between observed and estimated values). These methods allow non-intrusive and fully automated measurements of surfaces of unconsolidated granular material. With no tunable parameters or empirically derived coefficients, they should be broadly universal in appropriate applications. However, empirical corrections may need to be applied for the most accurate results. Finally, analytical formulas are derived for the one-step pore-particle transition probability matrix, estimated from the image's autocorrelogram, from which void fraction of a section of granular material can be estimated directly. This model gives excellent predictions of bulk void fraction yet imperfect predictions of pore-particle transitions.

Bricks as indicators for an urban soil genesis

NASA Astrophysics Data System (ADS)

Nehls, Thomas; Rokia, Sarah; Schwartz, Christophe; Wessolek, Gerd

2013-04-01

Bricks can be considered as anthropogenic markers since they are regularly found in urban soils worldwide. They are among the most resistent residues of building materials, therefore are called technogenic substrates. They have been dumped to urban soils since more than 4000 years and can be dated back to their burning using thermoluminescence. In Berlin, bricks have been piled up to more than 37 rubble mountains in the city after WW II. The devils mountain, the most prominent of them is higher than 60m. However, bricks are known not to be isolated in the soil but to fulfill soil functions due to their porosity. Therefore, they are nice research objects for soil scientists. The purpose of this study is to investigate abundance and functions of bricks in urban soils, focusing on plant nutrition and contamination aspects. Three different Berlin urban soils have been studied for their brick contents in the coarse and fine earth fractions by endless hand sorting. Light and scanning electron microscopy was then employed to investigate the bricks for proofs of plant roots. Third, CEC, pH, EC, Corg, nutrient storage (XRF) and availability (2:1 extract, ion chromatography, AAS) of bricks and fine earth fractions of the corresponding soil horizons have been investigated. The fine earth fractions of the investigated soils contain 3 to 5% of bricks, while the coarse fractions contain up to 50%. We found roots entering brick pores or at least attached to brick surfaces. Therefore, plants can use the water and nutrients stored in bricks. The CEC of bricks is grain size dependent and reaches a maximum of 6 cmolc kg-1 for particles smaller than 0.063 mm. This dependency is not explained by a low pore connectivity. Rather, it is the result of the restricted diffusion into the brick pore system due to the short shaking time in the CEC analysis protocol. From the nutrient storage and availabilities we conclude that bricks can better supply plants with K, Mg, Ca and S than the bulk soil at the investigated sandy site. However, in general, the nutrient availability from bricks is rather low compared to agricultural soils, except for Ca and S. Because of the water and nutrient storage, low contamination status and the possible rooting of bricks, they can be used for amelioration of poor sandy soils and for soil construction.

Simulating root-induced rhizosphere deformation and its effect on water flow

NASA Astrophysics Data System (ADS)

Aravena, J. E.; Ruiz, S.; Mandava, A.; Regentova, E. E.; Ghezzehei, T.; Berli, M.; Tyler, S. W.

2011-12-01

Soil structure in the rhizosphere is influenced by root activities, such as mucilage production, microbial activity and root growth. Root growth alters soil structure by moving and deforming soil aggregates, affecting water and nutrient flow from the bulk soil to the root surface. In this study, we utilized synchrotron X-ray micro-tomography (XMT) and finite element analysis to quantify the effect of root-induced compaction on water flow through the rhizosphere to the root surface. In a first step, finite element meshes of structured soil around the root were created by processing rhizosphere XMT images. Then, soil deformation by root expansion was simulated using COMSOL Multiphysics° (Version 4.2) considering the soil an elasto-plastic porous material. Finally, fluid flow simulations were carried out on the deformed mesh to quantify the effect of root-induced compaction on water flow to the root surface. We found a 31% increase in water flow from the bulk soil to the root due to a 56% increase in root diameter. Simulations also show that the increase of root-soil contact area was the dominating factor with respect to the calculated increase in water flow. Increase of inter-aggregate contacts in size and number were observed within a couple of root diameters away from the root surface. But their influence on water flow was, in this case, rather limited compared to the immediate soil-root contact.

Body weight management effect of burdock (Arctium lappa L.) root is associated with the activation of AMP-activated protein kinase in human HepG2 cells.

PubMed

Kuo, Daih-Huang; Hung, Ming-Chi; Hung, Chao-Ming; Liu, Li-Min; Chen, Fu-An; Shieh, Po-Chuen; Ho, Chi-Tang; Way, Tzong-Der

2012-10-01

Burdock (Arcticum lappa L.) root is used in folk medicine and also as a vegetable in Asian countries. In the present study, burdock root treatment significantly reduced body weight in rats. To evaluate the bioactive compounds, we successively extracted the burdock root with ethanol (AL-1), and fractionated it with n-hexane (AL-2), ethyl acetate (AL-3), n-butanol (AL-4), and water (AL-5). Among these fractions, AL-2 contained components with the most effective hypolipidemic potential in human hepatoma HepG2 cells. AL-2 decreased the expression of fatty acid synthase (FASN) and inhibited the activity of acetyl-coenzyme A carboxylase (ACC) by stimulating AMP-activated protein kinase (AMPK) through the LKB1 pathway. Three active compounds were identified from the AL-2, namely α-linolenic acid, methyl α-linolenate, and methyl oleate. These results suggest that burdock root is expected to be useful for body weight management. Copyright © 2012 Elsevier Ltd. All rights reserved.

[Effects of tillage practices on root spatial distribution and yield of spring wheat and pea in the dry land farming areas of central Gansu, China].

PubMed

Zhang, Ming Jun; Li, Ling Ling; Xie, Jun Hong; Peng, Zheng Kai; Ren, Jin Hu

2017-12-01

A field experiment was conducted to explore the mechanism of cultivation measures in affecting crop yield by investigating root distribution in spring wheat-pea rotation based on a long-term conservation tillage practices in a farming region of Gansu. The results showed that with the develo-pment of growth period, the total root length, root surface area of spring wheat and pea showed a consistent trend of increase after initial decrease and reached the maximum at flowering stage. Higher root distribution was found in the 0-10 cm soil layer at seedling and 10-30 cm soil layer at flowering and maturity stages in spring wheat, while in the field pea, higher root distribution was found in the 0-10 cm soil layer at seedling and maturity, and in the 10-30 cm soil layer at flowering stages. No tillage with straw mulching and plastic mulching increased the root length and root surface area. Compared with conventional tillage in spring wheat and field pea, root length increased by 35.9% to 92.6%, and root surface area increased by 43.2% to 162.4%, respectively. No tillage with straw mulching and plastic mulching optimized spring wheat and pea root system distribution, compared with conventional tillage, increased spring wheat and field pea root length and root surface area ratio at 0-10 cm depths at the seedling stage, the root distribution at deeper depths increased significantly at flowering and maturity stages, and no tillage with straw mulching increased root length and root surface area ratio by 3.3% and 9.7% respectively, in 30-80 cm soil layer at the flowering stage. The total root length, root surface area and yield had significantly positive correlation for spring wheat in each growth period, and the total root length and pea yield also had significant positive correlation. No tillage with straw mulching and plastic mulching boosted yield of spring wheat and pea by 23.4%-38.7% compared with the conventional tillage, and the water use efficiency was increased by 13.7%-28.5%. It was concluded that no-till farming and straw mulching (plastic) could increase crop root length and root surface area, optimize the spatial distribution of roots in the soil, enhance crop root layer absorption ability, so as to improve crop yield and water utilization.

The root economics spectrum: divergence of absorptive root strategies with root diameter

NASA Astrophysics Data System (ADS)

Kong, D.; Wang, J.; Kardol, P.; Wu, H.; Zeng, H.; Deng, X.; Deng, Y.

2015-08-01

Plant roots usually vary along a dominant ecological axis, the root economics spectrum (RES), depicting a tradeoff between resource acquisition and conservation. For absorptive roots, which are mainly responsible for resource acquisition, we hypothesized that root strategies as predicted from the RES shift with increasing root diameter. To test this hypothesis, we used seven contrasting plant species for which we separated absorptive roots into two categories: thin roots (< 247 μm diameter) and thick roots. For each category, we analyzed a~range of root traits closely related to resource acquisition and conservation, including root tissue density, carbon (C) and nitrogen (N) fractions as well as root anatomical traits. The results showed that trait relationships for thin absorptive roots followed the expectations from the RES while no clear trait relationships were found in support of the RES for thick absorptive roots. Our results suggest divergence of absorptive root strategies in relation to root diameter, which runs against a single economics spectrum for absorptive roots.

Partial Purification of a Legume Nodulation Factor Present in Coconut Water 1

PubMed Central

Schaffer, A. G.; Alexander, M.

1967-01-01

The nodulation of adventitious roots growing from segments of bean hypocotyl tissue was used as a bioassay for the material present in coconut water which stimulated nodulation. The active material in coconut water is acidic, but it was not possible to extract it from an acid solution with organic solvents. A purification of approximately 70-fold (on a dry wt basis) was obtained using activated charcoal, but at least 10 different compounds were present in the active fractions. A purified fraction of coconut water, which is stimulatory to the growth of carrot root explants, was active in the nodulation assay at a concentration of 2 μg/ml. This represents a 4000-fold purification of the diffusible fraction of coconut water. The charcoal fractionation procedure can be applied to the active material present in extracts of bean leaves. PMID:16656538

Two new triterpene saponins from the anti-inflammatory saponin fraction of Ilex pubescens root.

PubMed

Wang, Jing-Rong; Zhou, Hua; Jiang, Zhi-Hong; Liu, Liang

2008-07-01

The saponin fraction from the ethanolic extracts of the root of Ilex pubescens Hook. et Arn. (Ilexaceae) was found to exhibit potent anti-inflammatory effects on carrageenan-induced paw edema in rats. Two novel triterpene saponins, pubescenosides C and D (1 and 2, resp.), together with five known saponins were isolated from this saponin fraction. The structures of 1 and 2 were elucidated as (20beta)-3-O-[beta-D-glucopyranosyl-(1-->2)-beta-D-xylopyranosyl]ursa-12,18-dien-28-oic acid 28-O-beta-D-glucopyranosyl ester, and (20beta)-3-O-[alpha-L-rhamnopyranosyl-(1-->2)-beta-D-glucopyranosyl-(1-->2)-beta-D-xylopyranosyl]ursa- 12,18-dien-28-oic acid 28-O-beta-D-glucopyranosyl ester, respectively, on the basis of chemical and spectroscopic data. Five known saponins isolated from the saponin fraction were identified as ilexsaponin B(1), B(2), B(3), A(1), and chikusetsusaponin IV(a).

Amelioration of oxidative stress in bio-membranes and macromolecules by non-toxic dye from Morinda tinctoria (Roxb.) roots.

PubMed

Bhakta, Dipita; Siva, Ramamoorthy

2012-06-01

Plant dyes have been in use for coloring and varied purposes since prehistoric times. A red dye found in the roots of plants belonging to genus Morinda is a well recognized coloring ingredient. The dye fraction obtained from the methanolic extract of the roots of Morinda tinctoria was explored for its role in attenuating damages caused by H(2)O(2)-induced oxidative stress. The antioxidant potential of the dye fraction was assessed through DPPH radical scavenging, deoxyribose degradation and inhibition of lipid peroxidation in mice liver. It was subsequently screened for its efficiency in extenuating damage incurred to biomembrane (using erythrocytes and their ghost membranes) and macromolecules (pBR322 DNA, lipids and proteins) from exposure to hydrogen peroxide. In addition, the non-toxic nature of the dye was supported by the histological evaluation conducted on the tissue sections from the major organs of Swiss Albino mice as well as effect on Hep3B cell line (human hepatic carcinoma). The LC-MS confirms the dye fraction to be morindone. Our study strongly suggests that morindone present in the root extracts of M. tinctoria, in addition to being a colorant, definitely holds promise in the pharmaceutical industry. Copyright © 2012 Elsevier Ltd. All rights reserved.

[The genotypic diversity of oral Actinomyces naeslundii of root caries in aged people].

PubMed

Guo, Bin; Yang, Fan; Jia, Yue; Xia, Qian; Zhou, Xue-Dong

2010-12-01

To investigate the genotypic diversity of Actinomyces naeslundii in aged people and the relationship between the genotypes of Actinomyces naeslundii and root caries. According to the inclusion criteria, 20 aged people with root caries and 20 without root caries were chosen into two groups for this study. Two sites were chosen in subjects with root caries: One site was the exposed sound root surface, and the other site was the root caries. In subjects without root caries the sampling site of root surface was exposed. Bacteria were cultured and then identified. Repetitive extragenic palindromic sequence-based polymerase chain reaction (REP-PCR) was used to analyze the genotypic diversity of the Actinomyces naeslundii clinic isolates. 299 strains were isolated from the groups, 156 strains were chosen to analyze, belonged to 61 different genotypes. At the site of sound root surface in the subjects with root caries, there were 57 strains with 25 different patterns. At the site of root caries and of sound root surface in subjects without caries, there were 34 strains with 25 different patterns and 65 strains with 26 different patterns respectively. There was the genotypic diversity within Actinomyces naeslundii. There was significant difference in the genotypes in every individual site. Many different genotypes of Actinomyces naeslundii concerned with occurrence of root caries.

Estimation of runoff mitigation by morphologically different cover crop root systems

NASA Astrophysics Data System (ADS)

Yu, Yang; Loiskandl, Willibald; Kaul, Hans-Peter; Himmelbauer, Margarita; Wei, Wei; Chen, Liding; Bodner, Gernot

2016-07-01

Hydrology is a major driver of biogeochemical processes underlying the distinct productivity of different biomes, including agricultural plantations. Understanding factors governing water fluxes in soil is therefore a key target for hydrological management. Our aim was to investigate changes in soil hydraulic conductivity driven by morphologically different root systems of cover crops and their impact on surface runoff. Root systems of twelve cover crop species were characterized and the corresponding hydraulic conductivity was measured by tension infiltrometry. Relations of root traits to Gardner's hydraulic conductivity function were determined and the impact on surface runoff was estimated using HYDRUS 2D. The species differed in both rooting density and root axes thickness, with legumes distinguished by coarser axes. Soil hydraulic conductivity was changed particularly in the plant row where roots are concentrated. Specific root length and median root radius were the best predictors for hydraulic conductivity changes. For an intensive rainfall simulation scenario up to 17% less rainfall was lost by surface runoff in case of the coarsely rooted legumes Melilotus officinalis and Lathyrus sativus, and the densely rooted Linum usitatissimum. Cover crops with coarse root axes and high rooting density enhance soil hydraulic conductivity and effectively reduce surface runoff. An appropriate functional root description can contribute to targeted cover crop selection for efficient runoff mitigation.

Hyperaccumulation of cadmium by hairy roots of Thlaspi caerulescens

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

Nedelkoska, T.V.; Doran, P.M.

Hairy roots were used to investigate cadmium uptake by Thlaspi caerulescens, a metal hyperaccumulator plant with potential applications in phytoremediation and phytomining. Experiments were carried out in nutrient media under conditions supporting root growth. Accumulation of Cd in short-term (9-h) experiments varied with initial medium pH and increased after treating the roots with H{sup +}-ATPase inhibitor. The highest equilibrium Cd content measured in T. caerulescens roots was 62,800 {micro}g g{sup {minus}1} dry weight, or 6.3% dry weight, at a liquid Cd concentration of 3,710 ppm. Cd levels in live T. caerulescens roots were 1.5- to 1.7-fold those in hairy rootsmore » of nonhyperaccumulator species exposed to the same Cd concentration, but similar to the Cd content of auto-claved T. caerulescens roots. The ability to grow at Cd concentrations of up to 100 ppm clearly distinguished T. caerulescens hairy roots from the nonhyperaccumulators. The specific growth rate of T. caerulescens roots was essentially unaffected by 20 to 50 ppm Cd in the culture medium; in contrast, N. tabacum roots turned dark brown at 20 ppm and growth was negligible. Up to 10,600 {micro}g g{sup {minus}1} dry weight Cd was accumulated by growing T. caerulescens hairy roots. Measurement of Cd levels in while roots and in the cell wall fraction revealed significant differences in the responses of T. caerulescens and N. tabacum roots to 20 ppm Cd. Most metal was transported directly into the symplasm of N. tabacum roots within 3 days of exposure; in contrast, T. caerulescens roots stored virtually all of their Cd in the wall fraction for the first 7 to 10 days. This delay in transmembrane uptake may represent an important defensive strategy against Cd poisoning in T. caerulescens, allowing time for activation of intracellular mechanisms for heavy metal detoxification.« less

In-situ atrazine biodegradation dynamics in wheat (Triticum) crops under variable hydrologic regime.

PubMed

la Cecilia, Daniele; Maggi, Federico

2017-08-01

A comprehensive biodegradation reaction network of atrazine (ATZ) and its 18 byproducts was coupled to the nitrogen cycle and integrated in a computational solver to assess the in-situ biodegradation effectiveness and leaching along a 5m deep soil cultivated with wheat in West Wyalong, New South Wales, Australia. Biodegradation removed 97.7% of 2kg/ha ATZ yearly applications in the root zone, but removal substantially decreased at increasing depths; dechlorination removed 79% of ATZ in aerobic conditions and 18% in anaerobic conditions, whereas deethylation and oxidation removed only 0.11% and 0.15% of ATZ, respectively. The residual Cl mass fraction in ATZ and 4 byproducts was 2.4% of the applied mass. ATZ half-life ranged from 150 to 247days in the soil surface. ATZ reached 5m soil depth within 200years and its concentration increased from 1×10 -6 to 4×10 -6 mg/kg dry-soil over time. The correlation between ATZ specific biomass degradation affinity Φ 0 and half-life t 1/2 , although relatively uncertain for both hydrolyzing and oxidizing bacteria, suggested that microorganisms with high Φ 0 led to low ATZ t 1/2 . Greater ATZ applications were balanced by small nonlinear increments of ATZ biodegraded fraction within the root zone and therefore less ATZ leached into the shallow aquifer. Copyright © 2017 Elsevier B.V. All rights reserved.

In-situ atrazine biodegradation dynamics in wheat (Triticum) crops under variable hydrologic regime

NASA Astrophysics Data System (ADS)

la Cecilia, Daniele; Maggi, Federico

2017-08-01

A comprehensive biodegradation reaction network of atrazine (ATZ) and its 18 byproducts was coupled to the nitrogen cycle and integrated in a computational solver to assess the in-situ biodegradation effectiveness and leaching along a 5 m deep soil cultivated with wheat in West Wyalong, New South Wales, Australia. Biodegradation removed 97.7% of 2 kg/ha ATZ yearly applications in the root zone, but removal substantially decreased at increasing depths; dechlorination removed 79% of ATZ in aerobic conditions and 18% in anaerobic conditions, whereas deethylation and oxidation removed only 0.11% and 0.15% of ATZ, respectively. The residual Cl mass fraction in ATZ and 4 byproducts was 2.4% of the applied mass. ATZ half-life ranged from 150 to 247 days in the soil surface. ATZ reached 5 m soil depth within 200 years and its concentration increased from 1 ×10-6 to 4 ×10-6 mg/kgdry-soil over time. The correlation between ATZ specific biomass degradation affinity Φ0 and half-life t1/2, although relatively uncertain for both hydrolyzing and oxidizing bacteria, suggested that microorganisms with high Φ0 led to low ATZ t1/2. Greater ATZ applications were balanced by small nonlinear increments of ATZ biodegraded fraction within the root zone and therefore less ATZ leached into the shallow aquifer.

The α-amylase and α-glucosidase inhibitory activities of the dichloromethane extracts and constituents of Ferulago bracteata roots.

PubMed

Karakaya, Songül; Gözcü, Sefa; Güvenalp, Zühal; Özbek, Hilal; Yuca, Hafize; Dursunoğlu, Benan; Kazaz, Cavit; Kılıç, Ceyda Sibel

2018-12-01

Ferulago (Apiaceae) species have been used since ancient times for the treatment of intestinal worms, hemorrhoids, and as a tonic, digestive, aphrodisiac, or sedative, as well as in salads or as a spice due to their special odors. This study reports the α-amylase and α-glucosidase inhibitory activities of dichloromethane extract and bioactive compounds isolated from Ferulago bracteata Boiss. & Hausskn. roots. The isolated compounds obtained from dichloromethane extract of Ferulago bracteata roots through bioassay-guided fractionation and isolation process were evaluated for their in vitro α-amylase and α-glucosidase inhibitory activities at 5000-400 µg/mL concentrations. Compound structures were elucidated by detailed analyses (NMR and MS). A new coumarin, peucedanol-2'-benzoate (1), along with nine known ones, osthole (2), imperatorin (3), bergapten (4), prantschimgin (5), grandivitinol (6), suberosin (7), xanthotoxin (8), felamidin (9), umbelliferone (10), and a sterol mixture consisted of stigmasterol (11), β-sitosterol (12) was isolated from the roots of F. bracteata. Felamidin and suberosin showed significant α-glucosidase inhibitory activity (IC 50 0.42 and 0.89 mg/mL, respectively) when compared to the reference standard acarbose (IC 50 4.95 mg/mL). However, none of the tested extracts were found to be active on α-amylase inhibition. The present study demonstrated that among the compounds isolated from CH 2 Cl 2 fraction of F. bracteata roots, coumarins were determined as the main chemical constituents of this fraction. This is the first report on isolation and characterization of the bioactive compounds from root extracts of F. bracteata and on their α-amylase and α-glucosidase inhibitory activities.

Incorporation of 13C labeled Pinus ponderosa needle and fine root litter into soil organic matter measured by Py-GC/MS-C-IRMS

NASA Astrophysics Data System (ADS)

Mambelli, S.; Gleixner, G.; Dawson, T. E.; Bird, J. A.; Torn, M. S.

2006-12-01

Developing effective strategies for enhancing C storage in soils requires understanding the influence of plant C quality. In turn, plant C quality impacts the decay continuum between plant residue and humified, stable SOM. This remains one of the least understood aspects of soil biogeochemistry. We investigated the initial phase of incorporation of 13C labeled Pinus ponderosa needle and fine root litter into SOM. The two litter types were placed in separate microcosms in the A horizon in a temperate conifer soil. Curie-point pyrolysis-gas chromatography coupled with on-line mass spectrometry and isotope ratio mass spectrometry (Py-GC/MS-C- IRMS) were used to determine the identity and the 13C enrichment of pyrolysis products (fragments of carbohydrates, lignin, proteins and lipids). We compared the two initial litter types, needles and fine roots, to samples of the bulk soil (A horizon, < 2mm) and soil humin fraction (from chemical solubility) obtained from each microcosm 1.5y after litter addition. Pyrolysis of plant material and SOM produced 56 suitable products for isotopic analysis; of them, 15 occurred in both the litter and bulk soil, 7 in both the litter and the humin fraction and 9 in both bulk soil and the humin fraction. The pyrolysis products found in common in the plant and soil were related either to polysaccharides or were non-specific and could have originated from various precursors. The data suggest that the majority of plant inputs, both from needles or fine roots, were degraded very rapidly. In the humin fraction, the most recalcitrant pool of C in soil, with a measured turnover time of 260y (this soil), only products from the fragmentation of polysaccharides and alkyl-benzene compounds were found. Comparisons of the enrichment normalized by input level suggest little difference between the incorporation of C from needles versus fine roots into SOM. The most enriched fragments in the humin fraction were products from polysaccharides degradation, indicating a very important role of microbial processing in the stabilization of C in SOM.

Response of soil carbon fractions and dryland maize yield to mulching

USDA-ARS?s Scientific Manuscript database

Stimulation of root growth from mulching may enhance soil C fractions under maize (Zea mays L.). We studied the 5-yr straw (SM) and plastic film (PM) mulching effect on soil C fractions and maize yield compared with no mulching (CK) in the Loess Plateau of China. Soil samples collected from 0- to 10...

Antibacterial and antifungal activities of Dracontomelon dao.

PubMed

Khan, M R; Omoloso, A D

2002-07-01

The crude methanolic extracts of the leaves, stem and root barks of Drancantomelon dao and their subsequent partitioning (petrol, dichloromethane, ethyl acetate, butanol) gave fractions which demonstrated a very good level of broad spectrum antibacterial activity. The dichloromethane and butanol fractions of the leaf were the most active. Only the leaf fractions had antifungal activity, particularly the dichloromethane and butanol.

Bioassay-guided isolation of wound healing active compounds from Echium species growing in Turkey.

PubMed

Eruygur, Nuraniye; Yılmaz, Gülderen; Kutsal, Osman; Yücel, Gözde; Üstün, Osman

2016-06-05

The roots and root barks of Echium sp. have been used to treat ulcers, burns and wounds in traditional Turkish medicine. On the basis of them traditional use and literature references, four Echium species were selected for evaluation of them wound healing potential. Isolation of active component(s) from the active extracts through the bioassay guided fractionation procedures. In vivo the wound healing activity of the plants was evaluated by linear incision experimental models. The chloroform extract of Echium italicum L. was fractionated by successive chromatographic techniques. Wound healing activity of each fraction was investigated following the bioassay-guided fractionation procedures. Moreover, the tissue samples of isolated compounds were examined histopathologically. The healing potential was comparatively assessed with a reference ointment Madecassol®, which contains 1% extract of Centella asiatica. Significant wound healing activity was observed from the ointment prepared with ethanol extract at 1% concentration. The ethanol root extract treated in groups of animals showed a significant increase (37.38%, 40.97% and 35.29% separately for E. italicum L, Echium vulgare L. and Echium angustifolium Miller) wound tensile strength in the incision wound model. Subfractions showed significant but reduced wound healing activity on in vivo wound models. Shikonin derivatives "Acetylshikonin", "Deoxyshikonin" and "2-methyl-n-butyrylshikonin+Isovalerylshikonin", were isolated and determined as active components of active final subfraction from E. italicum L. roots. The results of histopathological examination supported the outcome of linear incision wound models. The experimental study revealed that Echium species display remarkable wound healing activity. Copyright © 2016. Published by Elsevier Ireland Ltd.

Where Is Needle- and Root-Derived Soil Organic Matter After 10 Years of Decomposition in a Temperate Forest?

NASA Astrophysics Data System (ADS)

Hicks Pries, C.; Hatton, P.; Castanha, C.; Bird, J. A.; Torn, M. S.

2013-12-01

All soil organic matter (SOM) is ultimately derived from plant litter. The fate of plant litter in ecosystems determines soil carbon (C) storage and nutrient availability with far-reaching implications for ecosystems and global change. However, little is known about the process by which litter becomes SOM (as opposed to the well-studied controls on rates of C and nitrogen (N) loss from litter). We are investigating whether litter type affects where in soils litter-derived C and N eventually reside. Specifically, we are investigating whether litter type affects which minerals the C and N are associated with and how much C is in the microbial pool after a decade. We incubated 15N and 13C-labeled Pinus ponderosa needle and fine root litter in the Blodgett Experimental Forest in the Sierra Nevada foothills for 10 years. A two-way factorial design was used with needle and root litter placed into O and A soil horizons. In 2001, litter was inserted into the given horizon within soil mesocosms (10.2 cm diameter x 24 cm long PVC) that had two 5 x 5 cm mesh windows to allow contact with the surrounding soil. After 0.5, 1, 1.5, 4.5, and 10 years, the soil mesocosms were collected from the field. Isotopes were used to measure the percent recovery of the litter C and N in the bulk soil of the O and A horizons. To investigate mineral associations of the added litter C and N after 10 years, we sequentially fractionated the soils by density. The fractions were a free light fraction (<1.75 g cm-3), a fraction dominated by phyllosilicate secondary minerals (1.75-2.5 g cm-3), a quartz and feldspar-dominated fraction (2.5-2.78 g cm-3), and a fraction dominated by biotite with kaolinite and iron oxide coatings (>2.78 g cm-3). To quantify the amount of litter-derived C actively cycling in the microbial pool after 10 years and use of the C by different microbial groups, we measured the 13C in phospholipid fatty acids (PLFAs). After 10 years, more root litter C (about 40%) was retained in the soil than needle litter C (about 25%). Less than 0.15% of the remaining litter C (0.06% of originally applied) was found actively cycling in microbial PLFA's. Needle and root C did not differ in the amount remaining still in the active microbial pool. Preliminary data indicate that unlike after one year, there were no microbial groups with strong preferences for the added root or needle C relative to other microbial groups. The amount of root and needle C and N associated with the different mineral groups will also be presented.

Modeling the erythemal surface diffuse irradiance fraction for Badajoz, Spain

NASA Astrophysics Data System (ADS)

Sanchez, Guadalupe; Serrano, Antonio; Cancillo, María Luisa

2017-10-01

Despite its important role on the human health and numerous biological processes, the diffuse component of the erythemal ultraviolet irradiance (UVER) is scarcely measured at standard radiometric stations and therefore needs to be estimated. This study proposes and compares 10 empirical models to estimate the UVER diffuse fraction. These models are inspired from mathematical expressions originally used to estimate total diffuse fraction, but, in this study, they are applied to the UVER case and tested against experimental measurements. In addition to adapting to the UVER range the various independent variables involved in these models, the total ozone column has been added in order to account for its strong impact on the attenuation of ultraviolet radiation. The proposed models are fitted to experimental measurements and validated against an independent subset. The best-performing model (RAU3) is based on a model proposed by Ruiz-Arias et al. (2010) and shows values of r2 equal to 0.91 and relative root-mean-square error (rRMSE) equal to 6.1 %. The performance achieved by this entirely empirical model is better than those obtained by previous semi-empirical approaches and therefore needs no additional information from other physically based models. This study expands on previous research to the ultraviolet range and provides reliable empirical models to accurately estimate the UVER diffuse fraction.

Complex I-complex II ratio strongly differs in various organs of Arabidopsis thaliana.

PubMed

Peters, Katrin; Niessen, Markus; Peterhänsel, Christoph; Späth, Bettina; Hölzle, Angela; Binder, Stefan; Marchfelder, Anita; Braun, Hans-Peter

2012-06-01

In most studies, amounts of protein complexes of the oxidative phosphorylation (OXPHOS) system in different organs or tissues are quantified on the basis of isolated mitochondrial fractions. However, yield of mitochondrial isolations might differ with respect to tissue type due to varying efficiencies of cell disruption during organelle isolation procedures or due to tissue-specific properties of organelles. Here we report an immunological investigation on the ratio of the OXPHOS complexes in different tissues of Arabidopsis thaliana which is based on total protein fractions isolated from five Arabidopsis organs (leaves, stems, flowers, roots and seeds) and from callus. Antibodies were generated against one surface exposed subunit of each of the five OXPHOS complexes and used for systematic immunoblotting experiments. Amounts of all complexes are highest in flowers (likewise with respect to organ fresh weight or total protein content of the flower fraction). Relative amounts of protein complexes in all other fractions were determined with respect to their amounts in flowers. Our investigation reveals high relative amounts of complex I in green organs (leaves and stems) but much lower amounts in non-green organs (roots, callus tissue). In contrast, complex II only is represented by low relative amounts in green organs but by significantly higher amounts in non-green organs, especially in seeds. In fact, the complex I-complex II ratio differs by factor 37 between callus and leaf, indicating drastic differences in electron entry into the respiratory chain in these two fractions. Variation in amounts concerning complexes III, IV and V was less pronounced in different Arabidopsis tissues (quantification of complex V in leaves was not meaningful due to a cross-reaction of the antibody with the chloroplast form of this enzyme). Analyses were complemented by in gel activity measurements for the protein complexes of the OXPHOS system and comparative 2D blue native/SDS PAGE analyses using isolated mitochondria. We suggest that complex I has an especially important role in the context of photosynthesis which might be due to its indirect involvement in photorespiration and its numerous enzymatic side activities in plants.

In vitro antimicrobial and antiprotozoal activities, phytochemical screening and heavy metals toxicity of different parts of Ballota nigra.

PubMed

Ullah, Najeeb; Ahmad, Ijaz; Ayaz, Sultan

2014-01-01

The study was done to assess the phytochemicals (flavonoids, terpenoids, saponins, tannin, alkaloids, and phenol) in different parts (root, stem, and leaves) of Ballota nigra and correlated it to inhibition of microbes (bacteria and fungi), protozoan (Leishmania), and heavy metals toxicity evaluation. In root and stem flavonoids, terpenes and phenols were present in ethanol, chloroform, and ethyl acetate soluble fraction; these were found to be the most active inhibiting fractions against all the tested strains of bacteria, fungi, and leishmania. While in leaves flavonoids, terpenes, and phenols were present in ethanol, chloroform, and n-butanol fractions which were the most active fractions against both types of microbes and protozoan (leishmania) in in vitro study. Ethanol and chloroform fractions show maximum inhibition against Escherichia coli (17 mm). The phytochemical and biological screenings were correlated with the presence of heavy metals in selected plant Ballota nigra. Cr was found above permissible value (above 1.5 mg/kg) in all parts of the plant. Ni was above WHO limit in B. nigra root and leaves (3.35 ± 1.20 mg/kg and 5.09 ± 0.47 mg/kg, respectively). Fe was above permissible value in all parts of B. nigra (above 20 mg/kg). Cd was above permissible value in all parts of the plant (above 0.3 mg/kg). Pb was above WHO limit (above 2 mg/kg) in all parts of Ballota nigra.

In Vitro Antimicrobial and Antiprotozoal Activities, Phytochemical Screening and Heavy Metals Toxicity of Different Parts of Ballota nigra

PubMed Central

Ullah, Najeeb; Ahmad, Ijaz; Ayaz, Sultan

2014-01-01

The study was done to assess the phytochemicals (flavonoids, terpenoids, saponins, tannin, alkaloids, and phenol) in different parts (root, stem, and leaves) of Ballota nigra and correlated it to inhibition of microbes (bacteria and fungi), protozoan (Leishmania), and heavy metals toxicity evaluation. In root and stem flavonoids, terpenes and phenols were present in ethanol, chloroform, and ethyl acetate soluble fraction; these were found to be the most active inhibiting fractions against all the tested strains of bacteria, fungi, and leishmania. While in leaves flavonoids, terpenes, and phenols were present in ethanol, chloroform, and n-butanol fractions which were the most active fractions against both types of microbes and protozoan (leishmania) in in vitro study. Ethanol and chloroform fractions show maximum inhibition against Escherichia coli (17 mm). The phytochemical and biological screenings were correlated with the presence of heavy metals in selected plant Ballota nigra. Cr was found above permissible value (above 1.5 mg/kg) in all parts of the plant. Ni was above WHO limit in B. nigra root and leaves (3.35 ± 1.20 mg/kg and 5.09 ± 0.47 mg/kg, respectively). Fe was above permissible value in all parts of B. nigra (above 20 mg/kg). Cd was above permissible value in all parts of the plant (above 0.3 mg/kg). Pb was above WHO limit (above 2 mg/kg) in all parts of Ballota nigra. PMID:25054139

Accumulation and ultrastructural distribution of copper in Elsholtzia splendens *

PubMed Central

Peng, Hong-yun; Yang, Xiao-e; Tian, Sheng-ke

2005-01-01

Copper accumulation and intracellular distribution in Elsholtzia splendens, a native Chinese Cu-tolerant and accumulating plant species, was investigated by transmission electron microscope (TEM) and gradient centrifugation techniques. Copper concentrations in roots, stems and leaves of E. splendens increased with increasing Cu levels in solution. After exposure to 500 μmol/L Cu for 8 d, about 1000 mg/kg Cu were accumulated in the stem and 250 mg/kg Cu in the leaf of E. splendens. At 50 µmol/L Cu, no significant toxicity was observed in the chloroplast and mitochondrion within its leaf cells, but separation appeared at the cytoplasm and the cell wall within the root cells. At >250 µmol/L Cu, both root and leaf organelles in E. splendens were damaged heavily by excessive Cu in vivo. Copper subcellular localization in the plant leaf after 8 days’ exposure to 500 µmol/L Cu using gradient centrifugation techniques was found to be decreased in the order: chloroplast>cell wall>soluble fraction>other organelles. The plant root cell wall was found to be the site of highest Cu localization. Increase of Cu exposure time from 8 d to 16 d, increased slightly Cu concentration in cell wall fraction in roots and leaves, while that in the chloroplast fraction decreased in leaves of the plants grown in both 0.25 μmol/L and 500 μmol/L Cu. TEM confirmed that much more Cu localized in cell walls of E. splendens roots and leaves, but also more Cu localized in E. splendens’ chloroplast when the plant is exposed to Cu levels>250 μmol/L, as compared to those in the plant grown in 0.25 μmol/L Cu. Copper treatment at levels>250 μmol/L caused pronounced damage in the leaf chloroplast and root organelles. Copper localization in cell walls and chloroplasts could mainly account for the high detoxification of Cu in E. splendens. PMID:15822140

Identification of Active Compounds in the Root of Merung (Coptosapelta tomentosa Valeton K. Heyne)

NASA Astrophysics Data System (ADS)

Fitriyana

2018-04-01

The roots of Merung (Coptosapelta tomentosa Valeton K. Heyne) are a group of shrubs usually found on the margins of secondary dryland forest. Empirically, local people have been using the roots of Merung for medical treatment. However, some researches show that the plant extract is used as a poisonous material applied on the tip of the arrow (dart). Based on the online literature study, there are less than 5 articles that provide information about the active compound of this root extract. This study aimed to give additional information more deeply about the content of active compound of Merung root extract in three fractions, n-hexane (nonpolar), ethyl acetate (semi polar) and methanol (polar). The extract was then analysed using Gas Chromatography-Mass Spectrometry (GC-MS). GC-MS analysis of root extract in n-hexane showed there were 56 compounds, with the main compound being decanoic acid, methyl ester (peak 5, 10.13%), 11-Octadecenoic acid, methyl ester (peak 15, 10.43%) and 1H-Pyrazole, 3- (4-chlorophenyl) -4, 5-dihydro-1-phenyl (peak 43, 11.25%). Extracts in ethyl acetate fraction obtained 81 compounds. The largest component is Benzoic acid (peak 19, 22.40%), whereas in methanol there are 38 compounds, of which the main component is 2-Furancarboxaldehyde, 5-(hydroxyl methyl) (peak 29, 30.46%).

The effect of EDTA in attachment gain and root coverage.

PubMed

Kassab, Moawia M; Cohen, Robert E; Andreana, Sebastiano; Dentino, Andrew R

2006-06-01

Root surface biomodification using low pH agents such as citric acid and tetracycline has been proposed to enhance root coverage following connective tissue grafting. The authors hypothesized that root conditioning with neutral pH edetic acid would improve vertical recession depth, root surface coverage, pocket depth, and clinical attachment levels. Twenty teeth in 10 patients with Miller class I and II recession were treated with connective tissue grafting. The experimental sites received 24% edetic acid in sterile distilled water applied to the root surface for 2 minutes before grafting. Controls were pretreated with only sterile distilled water. Measurements were evaluated before surgery and 6 months after surgery. Analysis of variance was used to determine differences between experimental and control groups. We found significant postoperative improvements in vertical recession depth, root surface coverage, and clinical attachment levels in test and control groups, compared to postoperative data. Pocket depth differences were not significant (P<.01).

Sheared-root inocula of vesicular-arbuscular mycorrhizal fungi.

PubMed

Sylvia, D M; Jarstfer, A G

1992-01-01

For efficient handling, vesicular-arbuscular mycorrhizal fungi should be processed into small and uniform inocula; however, processing can reduce the inoculum density. In this article we describe the preparation and use of sheared-root inocula of Glomus spp. in which inoculum densities were increased during processing. Our objectives were to determine inoculum viability and density after shearing and to ascertain if the sheared inocula could be pelletized or used with a gel carrier. Root samples were harvested from aeroponic cultures, blotted dry, cut into 1-cm lengths, and sheared in a food processor for up to 80 s. After shearing, the inoculum was washed over sieves, and the propagule density in each fraction was determined. Sheared inocula were also encapsulated in carrageenan or used in a gel carrier. Shearing aeroponically produced root inocula reduced particle size. Propagule density increased with decreasing size fraction down to a size of 63 mum, after which propagule density decreased. The weighted-average propagule density of the inoculum was 135,380 propagules g (dry weight) of sheared root material. Sheared roots were encapsulated successfully in carrageenan, and the gel served as an effective carrier. Aeroponic root inoculum was stored dry at 4 degrees C for 23 months without significant reduction in propagule density; however, this material was not appropriate for shearing. Moist roots, useful for shearing, began to lose propagule density after 1 month of storage. Shearing proved to be an excellent method to prepare viable root inocula of small and uniform size, allowing for more efficient and effective use of limited inoculum supplies.

Characterizing the changes in biopolymer composition in roots of photosynthetically divergent grasses exposed to future climates

NASA Astrophysics Data System (ADS)

Suseela, V.; Tharayil, N.; Pendall, E.

2014-12-01

A majority of carbon in soil is derived from plant roots, yet roots remain remarkably less explored. Root tissues are abundant in heteropolymers such as suberin, lignin and tannins which are energetically demanding to depolymerize, thus facilitating the accrual of carbon in soil. Most biopolymers are operationally/functionally defined and their function is regulated by the identity of monomers and the linkages connecting these monomers. The structural chemistry of these biopolymers could vary with the environmental conditions experienced during their formative stage thus altering the potential for soil carbon sequestration. We examined the biopolymer composition in the roots of a C3 (Hesperostipa comata) and a C4 (Bouteloua gracilis) grass species exposed to a factorial combination of warming and elevated CO2 at the Prairie Heating and CO2 Enrichment (PHACE) experiment, Wyoming, USA. The grass roots were subjected to a sequential solvent extraction and base hydrolysis to delineate various operational fractions within the polydisperse matrix. The extracted fractions were analyzed using various chromatography mass spectrometry platforms. Warming and elevated CO2 increased the total suberin content and the amount of ω-hydroxy acids in C4 grass species while in C3 species there was a trend of increasing concentration of α,ω-dioic acids in roots exposed to elevated CO2 compared to ambient CO2 treatment. Our results highlight the effect of warming and elevated CO2 on the chemical composition of heteropolymers in roots that may potentially alter root function and rate of decomposition leading to changes in soil carbon in a future warmer world.

Quantitative evaluation of root canal surface roughness after filing with adaptive reciprocating and continuous rotary instruments.

PubMed

Sakhaei Manesh, Vahid; Giacomin, Paul; Stoll, Richard

2017-06-01

Obtaining clean and smooth root canal walls is the ideal clinical outcome of the cleaning and shaping stage in root canal treatment. This study compares the surface roughness of root canal surfaces instrumented with a NiTi filing system with either adaptive reciprocating (AR) or continuous rotation (CR). Root canal cleaning and shaping was carried out on the mesial canals of 24 extracted first molars roots with either AR or CR. Roots were split in half and the surface roughness of their canals was evaluated in 12 three dimensional roughness reconstructions using a scanning electron microscope. Rz (nm) values were calculated in three areas of each reconstruction and analyzed (α = 0.05). Mann-Whitney tests showed that surface roughness was significantly higher overall in the AR group (Rz = 967 ± 250 nm) compared with the CR group (Rz = 739 ± 239 nm; p = 0.044). The roughness values generally increased from apical towards the coronal third in both groups. A less aggressive finishing file or a continuous rotary system to end the cleaning and shaping stage may be beneficial to reduce roughness of the root canal surface. © 2017 Wiley Periodicals, Inc.

Transfer of radiocesium from rhizosphere soil to four cruciferous vegetables in association with a Bacillus pumilus strain and root exudation.

PubMed

Aung, Han Phyo; Mensah, Akwasi Dwira; Aye, Yi Swe; Djedidi, Salem; Oikawa, Yosei; Yokoyama, Tadashi; Suzuki, Sohzoh; Dorothea Bellingrath-Kimura, Sonoko

2016-11-01

This study was carried out to assess the effect of Bacillus pumilus on the roots of four cruciferous vegetables with different root structures in regard to enhancement of 137 Cs bioavailability in contaminated rhizosphere soil. Results revealed that B. pumilus inoculation did not enhance the plant biomass of vegetables, although it increased root volume and root surface areas of all vegetables except turnip. The pH changes due to rhizosphere acidification by B. pumilus inoculation and root exudation did not affect the bioavailability of 137 Cs. However, concentrations of 137 Cs in plant tissues and soil-to-plant transfer values increased as a result of the larger root volume and root surface area of vegetables due to inoculation. Moreover, leafy vegetables, which possessed larger root volume and root surface areas, had a higher 137 Cs transfer value than root vegetables. Copyright © 2016 Elsevier Ltd. All rights reserved.

Micro-CT and nano-CT analysis of filling quality of three different endodontic sealers.

PubMed

Huang, Yan; Celikten, Berkan; de Faria Vasconcelos, Karla; Ferreira Pinheiro Nicolielo, Laura; Lippiatt, Nicholas; Buyuksungur, Arda; Jacobs, Reinhilde; Orhan, Kaan

2017-12-01

To investigate voids in different root canal sealers using micro-CT and nano-CT, and to explore the feasibility of using nano-CT for quantitative analysis of sealer filling quality. 30 extracted mandibular central incisors were randomly assigned into three groups according to the applied root canal sealers (Total BC Sealer, Sure Seal Root, AH Plus) by the single cone technique. Subsequently, micro-CT and nano-CT were performed to analyse the incidence rate of voids, void fraction, void volume and their distribution in each sample. Micro-CT evaluation showed no significant difference among sealers for the incidence rate of voids or void fraction in the whole filling materials (p > 0.05), whereas a significant difference was found between AH Plus and the other two sealers using nano-CT (p < 0.05). All three sealers presented less void volume in the apical third; however, higher void volumes were observed in the apical and coronal thirds in AH Plus using micro-CT (p < 0.05), while nano-CT results displayed higher void volume in AH Plus among all the sealers and regions (p < 0.05). Bioactive sealers showed higher root filling rate, lower incidence rate of voids, void fraction and void volume than AH Plus under nano-CT analysis, when round root canals were treated by the single cone technique. The disparate results suggest that the higher resolution of nano-CT have a greater ability of distinguishing internal porosity, and therefore suggesting the potential use of nano-CT in quantitative analysis of filling quality of sealers.

Land-atmosphere coupling and climate prediction over the U.S. Southern Great Plains

NASA Astrophysics Data System (ADS)

Williams, Ian N.; Lu, Yaqiong; Kueppers, Lara M.; Riley, William J.; Biraud, Sebastien C.; Bagley, Justin E.; Torn, Margaret S.

2016-10-01

Biases in land-atmosphere coupling in climate models can contribute to climate prediction biases, but land models are rarely evaluated in the context of this coupling. We tested land-atmosphere coupling and explored effects of land surface parameterizations on climate prediction in a single-column version of the National Center for Atmospheric Research Community Earth System Model (CESM1.2.2) and an off-line Community Land Model (CLM4.5). The correlation between leaf area index (LAI) and surface evaporative fraction (ratio of latent to total turbulent heat flux) was substantially underpredicted compared to observations in the U.S. Southern Great Plains, while the correlation between soil moisture and evaporative fraction was overpredicted by CLM4.5. To estimate the impacts of these errors on climate prediction, we modified CLM4.5 by prescribing observed LAI, increasing soil resistance to evaporation, increasing minimum stomatal conductance, and increasing leaf reflectance. The modifications improved the predicted soil moisture-evaporative fraction (EF) and LAI-EF correlations in off-line CLM4.5 and reduced the root-mean-square error in summer 2 m air temperature and precipitation in the coupled model. The modifications had the largest effect on prediction during a drought in summer 2006, when a warm bias in daytime 2 m air temperature was reduced from +6°C to a smaller cold bias of -1.3°C, and a corresponding dry bias in precipitation was reduced from -111 mm to -23 mm. The role of vegetation in droughts and heat waves is underpredicted in CESM1.2.2, and improvements in land surface models can improve prediction of climate extremes.

Effect of EDTA, sodium hypochlorite, and chlorhexidine gluconate with or without surface modifiers on dentin microhardness.

PubMed

Aslantas, Eda E; Buzoglu, Hatice Dogan; Altundasar, Emre; Serper, Ahmet

2014-06-01

This study aimed to evaluate the effects of root canal irrigants on the microhardness of root canal dentin in the presence and absence of surface-modifying agents. Forty-eight root halves were prepared by longitudinal splitting of the distal roots of 24 freshly extracted mandibular human third molars and embedded in autopolymerizing acrylic resin, leaving the dentin surface exposed. After polishing, the microhardness values of the untreated dentin surfaces were recorded by using Vickers tester at the mid-root level. The root halves were randomly assigned to 6 groups composed of 8 samples each and treated for 5 minutes with one of the following irrigants: 17% EDTA, REDTA, 2% chlorhexidine gluconate (CHX), 2% CHX with surface modifiers (CHX-Plus), 6% NaOCl, or 6% NaOCl with surface modifiers (Chlor-XTRA). After surface treatment, dentin microhardness values were recorded at close proximity to the initial indentation areas. Experimental data were statistically analyzed by using the t test and one-way analysis of variance, followed by Tukey honestly significant difference test at α = 0.05. EDTA, REDTA, NaOCl, and Chlor-XTRA significantly decreased the microhardness of root dentin compared with intact controls (P < .05). The addition of surface modifiers to the irrigants did not affect the microhardness of the samples. Copyright © 2014 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

LC-MS identification and preparative HPLC isolation of Frankenia pulverulenta phenolics with antioxidant and neuroprotective capacities in PC12 cell line.

PubMed

Ben Mansour, Rim; Wided, Megdiche Ksouri; Cluzet, Stéphanie; Krisa, Stéphanie; Richard, Tristan; Ksouri, Riadh

2017-12-01

Frankenia pulverulenta L. (Frankeniaceae) is a medicinal species with carminative, analgesic and antiviral properties. However, phytochemical investigations, antioxidant and neuroprotective capacities of this plant remain unclear. This work assesses the phenolic composition of F. pulverulenta shoot and root and evaluates their antioxidant and neuroprotective capacities. Successive fractionation of F. pulverulenta shoot and root using 6 solvents were used. Antioxidant capacity of these fractions was assessed through four in vitro tests (DPPH, ABTS, Fe-chelating activity and ORAC). Phenolic identification, purification as well as neuroprotective activity of ethyl acetate (EtOAc) fraction and purified molecules were assessed. Among the tested fractions, EtOAc shoot and root fractions possessed considerable phenolic contents (383 and 374 mg GAE/g E, respectively) because of their important ORAC (821 and 1054 mg of TE/g E), DPPH (586 and 750 mg of TE/g) and ABTS (1453 and 1319 mg of TE/g) results. Moreover, gallic acid, quercetin, quercetin galloyl glucoside, trigalloyl hexoside, procyanidin dimers and sulfated flavonoids were identified by LC-DAD-ESI-MS for the first time in this species. The relevant cytoprotective capacity (at 300 μg/mL) against β-amyloid peptide induced toxicity in PC12 cells of EtOAc fractions were corroborated with the chemical composition. In addition, purified molecules were tested for their ORAC and neuroprotective activity. Quercetin showed the best ORAC value (33.55 mmol TE/g polyphenols); nevertheless, procyanidin dimer exhibited an exceptionally efficient neuroprotective activity (100% of viability at 50 μg/mL). These findings suggest that this halophyte is a promising source of antioxidant and neuroprotective molecules for pharmaceutical purposes.

Transport, ultrastructural localization, and distribution of chemical forms of lead in radish (Raphanus sativus L.)

PubMed Central

Wang, Yan; Shen, Hong; Xu, Liang; Zhu, Xianwen; Li, Chao; Zhang, Wei; Xie, Yang; Gong, Yiqin; Liu, Liwang

2015-01-01

Lead (Pb), a ubiquitous but highly toxic heavy metal (HM), is harmful to human health through various pathways including by ingestion of contaminated vegetables. Radish is a worldwide root vegetable crop with significant health and nutritional benefits. However, little is known about Pb translocation and distribution within radish plants after its uptake by the roots. In this study, Pb stress was induced using Pb(NO3)2 in hydroponic culture, aiming to characterize the transport, ultrastructural localization, and distribution of chemical forms of Pb in different tissues of radish. The results showed that the majority of Pb (85.76–98.72%) was retained in underground organs including lateral roots, root heads and taproot skins, while a small proportion of Pb was absorbed by root flesh (0.44–1.56%) or transported to the shoot (1.28–14.24%). A large proportion of Pb (74.11–99.30%) was integrated with undissolved Pb oxalate, protein and pectates forming Pb–phosphate complexes. Moreover, a low-Pb-accumulating line of radish showed a higher proportion of Pb in water-soluble form compared with a high-Pb-accumulating line. Subcellular distribution analysis showed that a large proportion of Pb was bound to cell wall fraction in lateral roots (71.08–80.40%) and taproot skin (46.22–77.94%), while the leaves and roots had 28.36–39.37% and 27.35–46.51% of Pb stored in the soluble fraction, respectively. Furthermore, transmission electron microscopy (TEM) revealed Pb precipitates in intercellular space, cell wall, plasma lemma and vacuoles. Fractionation results also showed the accumulation of Pb on the cell wall, intercellular space and vacuole, and low uptake of undissolved Pb oxalate, protein, pectates and Pb–phosphate complexes, which might be due to low transport efficiency and Pb tolerance of radish. These findings would provide insight into molecular mechanism of Pb uptake and translocation in radish and facilitate development of low-Pb-content cultivars in root vegetable crops. PMID:26005445

How does biomass distribution change with size and differ among species? An analysis for 1200 plant species from five continents.

PubMed

Poorter, Hendrik; Jagodzinski, Andrzej M; Ruiz-Peinado, Ricardo; Kuyah, Shem; Luo, Yunjian; Oleksyn, Jacek; Usoltsev, Vladimir A; Buckley, Thomas N; Reich, Peter B; Sack, Lawren

2015-11-01

We compiled a global database for leaf, stem and root biomass representing c. 11 000 records for c. 1200 herbaceous and woody species grown under either controlled or field conditions. We used this data set to analyse allometric relationships and fractional biomass distribution to leaves, stems and roots. We tested whether allometric scaling exponents are generally constant across plant sizes as predicted by metabolic scaling theory, or whether instead they change dynamically with plant size. We also quantified interspecific variation in biomass distribution among plant families and functional groups. Across all species combined, leaf vs stem and leaf vs root scaling exponents decreased from c. 1.00 for small plants to c. 0.60 for the largest trees considered. Evergreens had substantially higher leaf mass fractions (LMFs) than deciduous species, whereas graminoids maintained higher root mass fractions (RMFs) than eudicotyledonous herbs. These patterns do not support the hypothesis of fixed allometric exponents. Rather, continuous shifts in allometric exponents with plant size during ontogeny and evolution are the norm. Across seed plants, variation in biomass distribution among species is related more to function than phylogeny. We propose that the higher LMF of evergreens at least partly compensates for their relatively low leaf area : leaf mass ratio. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

Subcellular Compartmentalization and Chemical Forms of Lead Participate in Lead Tolerance of Robinia pseudoacacia L. with Funneliformis mosseae

PubMed Central

Huang, Li; Zhang, Haoqiang; Song, Yingying; Yang, Yurong; Chen, Hui; Tang, Ming

2017-01-01

The effect of arbuscular mycorrhizal fungus on the subcellular compartmentalization and chemical forms of lead (Pb) in Pb tolerance plants was assessed in a pot experiment in greenhouse conditions. We measured root colonization, plant growth, photosynthesis, subcellular compartmentalization and chemical forms of Pb in black locust (Robinia pseudoacacia L.) seedlings inoculated with Funneliformis mosseae isolate (BGC XJ01A) under a range of Pb treatments (0, 90, 900, and 3000 mg Pb kg-1 soil). The majority of Pb was retained in the roots of R. pseudoacacia under Pb stress, with a significantly higher retention in the inoculated seedlings. F. mosseae inoculation significantly increased the proportion of Pb in the cell wall and soluble fractions and decreased the proportion of Pb in the organelle fraction of roots, stems, and leaves, with the largest proportion of Pb segregated in the cell wall fraction. F. mosseae inoculation increased the proportion of inactive Pb (especially pectate- and protein-integrated Pb and Pb phosphate) and reduced the proportion of water-soluble Pb in the roots, stems, and leaves. The subcellular compartmentalization of Pb in different chemical forms was highly correlated with improved plant biomass, height, and photosynthesis in the inoculated seedlings. This study indicates that F. mosseae could improve Pb tolerance in R. pseudoacacia seedlings growing in Pb polluted soils. PMID:28443111

Viper and cobra venom neutralization by beta-sitosterol and stigmasterol isolated from the root extract of Pluchea indica Less. (Asteraceae).

PubMed

Gomes, A; Saha, Archita; Chatterjee, Ipshita; Chakravarty, A K

2007-09-01

We reported previously that the methanolic root extract of the Indian medicinal plant Pluchea indica Less. (Asteraceae) could neutralize viper venom-induced action [Alam, M.I., Auddy, B., Gomes, A., 1996. Viper venom neutralization by Indian medicinal plant (Hemidesmus indicus and P. indica) root extracts. Phytother. Res. 10, 58-61]. The present study reports the neutralization of viper and cobra venom by beta-sitosterol and stigmasterol isolated from the root extract of P. indica Less. (Asteraceae). The active fraction (containing the major compound beta-sitosterol and the minor compound stigmasterol) was isolated and purified by silica gel column chromatography and the structure was determined using spectroscopic analysis (EIMS, (1)H NMR, (13)C NMR). Anti-snake venom activity was studied in experimental animals. The active fraction was found to significantly neutralize viper venom-induced lethal, hemorrhagic, defibrinogenation, edema and PLA(2) activity. Cobra venom-induced lethality, cardiotoxicity, neurotoxicity, respiratory changes and PLA(2) activity were also antagonized by the active component. It potentiated commercial snake venom antiserum action against venom-induced lethality in male albino mice. The active fraction could antagonize venom-induced changes in lipid peroxidation and superoxide dismutase activity. This study suggests that beta-sitosterol and stigmasterol may play an important role, along with antiserum, in neutralizing snake venom-induced actions.

Changes in subcellular distribution and antioxidant compounds involved in Pb accumulation and detoxification in Neyraudia reynaudiana.

PubMed

Zhou, Chuifan; Huang, Meiying; Li, Ying; Luo, Jiewen; Cai, Li Ping

2016-11-01

The effects of increasing concentrations of lead (Pb) on Pb accumulation, subcellular distribution, ultrastructure, photosynthetic characteristics, antioxidative enzyme activity, malondialdehyde content, and phytochelatin contents were investigated in Neyraudia reynaudiana seedlings after a 21-day exposure. A Pb analysis at the subcellular level showed that the majority of Pb in the roots was associated with the cell wall fraction, followed by the soluble fraction. In contrast, the majority of the Pb in the leaves was located in the soluble fraction based on transmission electron microscopy and energy dispersive X-ray analyses. Furthermore, high Pb concentrations adversely affected N. reynaudiana cellular structure. The changes in enzyme activity suggested that the antioxidant system plays an important role in eliminating or alleviating Pb toxicity, both in the roots and leaves of N. reynaudiana. Additionally, the phytochelatin contents in the roots and leaves differed significantly between Pb-spiked treatments and control plants. Our results provide strong evidence that cell walls restrict Pb uptake into the protoplasm and establish an important protective barrier. Subsequent vacuolar compartmentalization in leaves could isolate Pb from other substances in the cell and minimize Pb toxicity in other organelles over time. These results also demonstrated that the levels of antioxidant enzymes and phytochelatin in leaves and roots are correlated with Pb toxicity. These detoxification mechanisms promote Pb tolerance in N. reynaudiana.

Phenotypic variation of Pseudomonas brassicacearum as a plant root-colonization strategy.

PubMed

Achouak, Wafa; Conrod, Sandrine; Cohen, Valérie; Heulin, Thierry

2004-08-01

Pseudomonas brassicacearum was isolated as a major root-colonizing population from Arabidopsis thaliana. The strain NFM421 of P. brassicacearum undergoes phenotypic variation during A. thaliana and Brassica napus root colonization in vitro as well as in soil, resulting in different colony appearance on agar surfaces. Bacteria forming translucent colonies (phase II cells) essentially were localized at the surface of young roots and root tips, whereas wild-type cells (phase I cells) were localized at the basal part of roots. The ability of phase II cells to spread and colonize new sites on root surface correlates with over-production of flagellin as evidenced by sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis of surface proteins and microsequencing. Moreover, phase II cells showed a higher ability to swim and to swarm on semisolid agar medium. Phase I and phase II cells of P. brassicacearum NFM421 were tagged genetically with green fluorescent protein and red fluorescent protein. Confocal scanning laser microscopy was used to localize phase II cells on secondary roots and root tips of A. thaliana, whereas phase I cells essentially were localized at the basal part of roots. These experiments were conducted in vitro and in soil. Phenotypic variation on plant roots is likely to be a colonization strategy that may explain the high colonization power of P. brassicacearum.

Dispersion of kaolinite by dissolved organic matter from Douglas-fir roots

Treesearch

Philip B. Durgin; Jesse G. Chaney

1984-01-01

The organic constituents of water extracts from Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco var. menziesii) roots that cause kaolinite dispersion were investigated. The dissolved organic matter was fractionated according to molecular size and chemical characteristics into acids, neutrals, and bases of the hydrophilic and hydrophobic groups.

Catharanthus alkaloids XXXII: isolation of alkaloids from Catharanthus trichophyllus roots and structure elucidation of cathaphylline.

PubMed

Cordell, G A; Farnsworth, N R

1976-03-01

Further examination of the cytotoxic alkaloid fractions of Catharanthus trichophyllus roots afforded nine alkaloids. Two of these alkaloids, lochnericine and horhammericine, are responsible for part of the cytotoxic activity. The structure elucidation of cathaphylline, a new beta-anilino acrylate derivative, is described.

The effect of root surface conditioning on smear layer removal in periodontal regeneration (a scanning electron microscopic study)

NASA Astrophysics Data System (ADS)

Fidyawati, D.; Soeroso, Y.; Masulili, S. L. C.

2017-08-01

The role of root surface conditioning treatment on smear layer removal of human teeth is affected by periodontitis in periodontal regeneration. The objective of this study is to analyze the smear layer on root surface conditioned with 2.1% minocycline HCl ointment (Periocline), and 24% EDTA gel (Prefgel). A total of 10 human teeth indicated for extraction due to chronic periodontitis were collected and root planed. The teeth were sectioned in thirds of the cervical area, providing 30 samples that were divided into three groups - minocycline ointment treatment, 24% EDTA gel treatment, and saline as a control. The samples were examined by scanning electron microscope. No significant differences in levels of smear layer were observed between the minocycline group and the EDTA group (p=0.759). However, there were significant differences in the level of smear layer after root surface treatment in the minocycline and EDTA groups, compared with the control group (p=0.00). There was a relationship between root surface conditioning treatment and smear layer levels following root planing.

High-order fractional partial differential equation transform for molecular surface construction.

PubMed

Hu, Langhua; Chen, Duan; Wei, Guo-Wei

2013-01-01

Fractional derivative or fractional calculus plays a significant role in theoretical modeling of scientific and engineering problems. However, only relatively low order fractional derivatives are used at present. In general, it is not obvious what role a high fractional derivative can play and how to make use of arbitrarily high-order fractional derivatives. This work introduces arbitrarily high-order fractional partial differential equations (PDEs) to describe fractional hyperdiffusions. The fractional PDEs are constructed via fractional variational principle. A fast fractional Fourier transform (FFFT) is proposed to numerically integrate the high-order fractional PDEs so as to avoid stringent stability constraints in solving high-order evolution PDEs. The proposed high-order fractional PDEs are applied to the surface generation of proteins. We first validate the proposed method with a variety of test examples in two and three-dimensional settings. The impact of high-order fractional derivatives to surface analysis is examined. We also construct fractional PDE transform based on arbitrarily high-order fractional PDEs. We demonstrate that the use of arbitrarily high-order derivatives gives rise to time-frequency localization, the control of the spectral distribution, and the regulation of the spatial resolution in the fractional PDE transform. Consequently, the fractional PDE transform enables the mode decomposition of images, signals, and surfaces. The effect of the propagation time on the quality of resulting molecular surfaces is also studied. Computational efficiency of the present surface generation method is compared with the MSMS approach in Cartesian representation. We further validate the present method by examining some benchmark indicators of macromolecular surfaces, i.e., surface area, surface enclosed volume, surface electrostatic potential and solvation free energy. Extensive numerical experiments and comparison with an established surface model indicate that the proposed high-order fractional PDEs are robust, stable and efficient for biomolecular surface generation.

Characterizing the cytoprotective activity of Sarracenia purpurea L., a medicinal plant that inhibits glucotoxicity in PC12 cells.

PubMed

Harris, Cory S; Asim, Muhammad; Saleem, Ammar; Haddad, Pierre S; Arnason, John T; Bennett, Steffany A L

2012-12-05

The purple pitcher plant, Sarracenia purpurea L., is a widely distributed species in North America with a history of use as both a marketed pain therapy and a traditional medicine in many aboriginal communities. Among the Cree of Eeyou Istchee in northern Québec, the plant is employed to treat symptoms of diabetes and the leaf extract demonstrates multiple anti-diabetic activities including cytoprotection in an in vitro model of diabetic neuropathy. The current study aimed to further investigate this activity by identifying the plant parts and secondary metabolites that contribute to these cytoprotective effects. Ethanolic extracts of S. purpurea leaves and roots were separately administered to PC12 cells exposed to glucose toxicity with subsequent assessment by two cell viability assays. Assay-guided fractionation of the active extract and fractions was then conducted to identify active principles. Using high pressure liquid chromatography together with mass spectrometry, the presence of identified actives in both leaf and root extracts were determined. The leaf extract, but not that of the root, prevented glucose-mediated cell loss in a concentration-dependent manner. Several fractions elicited protective effects, indicative of multiple active metabolites, and, following subfractionation of the polar fraction, hyperoside (quercetin-3-O-galactoside) and morroniside were isolated as active constituents. Phytochemical analysis confirmed the presence of hyperoside in the leaf but not root extract and, although morroniside was detected in both organs, its concentration was seven times higher in the leaf. Our results not only support further study into the therapeutic potential and safety of S. purpurea as an alternative and complementary treatment for diabetic complications associated with glucose toxicity but also identify active principles that can be used for purposes of standardization and quality control.

Characterizing the cytoprotective activity of Sarracenia purpurea L., a medicinal plant that inhibits glucotoxicity in PC12 cells

PubMed Central

2012-01-01

Background The purple pitcher plant, Sarracenia purpurea L., is a widely distributed species in North America with a history of use as both a marketed pain therapy and a traditional medicine in many aboriginal communities. Among the Cree of Eeyou Istchee in northern Québec, the plant is employed to treat symptoms of diabetes and the leaf extract demonstrates multiple anti-diabetic activities including cytoprotection in an in vitro model of diabetic neuropathy. The current study aimed to further investigate this activity by identifying the plant parts and secondary metabolites that contribute to these cytoprotective effects. Methods Ethanolic extracts of S. purpurea leaves and roots were separately administered to PC12 cells exposed to glucose toxicity with subsequent assessment by two cell viability assays. Assay-guided fractionation of the active extract and fractions was then conducted to identify active principles. Using high pressure liquid chromatography together with mass spectrometry, the presence of identified actives in both leaf and root extracts were determined. Results The leaf extract, but not that of the root, prevented glucose-mediated cell loss in a concentration-dependent manner. Several fractions elicited protective effects, indicative of multiple active metabolites, and, following subfractionation of the polar fraction, hyperoside (quercetin-3-O-galactoside) and morroniside were isolated as active constituents. Phytochemical analysis confirmed the presence of hyperoside in the leaf but not root extract and, although morroniside was detected in both organs, its concentration was seven times higher in the leaf. Conclusion Our results not only support further study into the therapeutic potential and safety of S. purpurea as an alternative and complementary treatment for diabetic complications associated with glucose toxicity but also identify active principles that can be used for purposes of standardization and quality control. PMID:23216659

Liquid Chromatography Mass Spectrometry Analysis and Cytotoxicity of Asparagus adscendens Roots against Human Cancer Cell Lines.

PubMed

Khan, Kashif Maqbool; Nahar, Lutfun; Mannan, Abdul; Arfan, Muhammad; Khan, Ghazanfar Ali; Al-Groshi, Afaf; Evans, Andrew; Dempster, Nicola M; Ismail, Fyaz M D; Sarker, Satyajit D

2018-01-01

Asparagus adscendens Roxb. (Asparagaceae), is native to the Himalayas. This plant has been used in the prevention and effective treatment of various forms of cancers. This paper reports, for the first time, on the cytotoxicity of the methanol (MeOH) extract of the roots of A. adscendens and its solid-phase extraction (SPE) fractions against four human carcinoma cell lines and LC-ESI-QTOF-MS analysis of the SPE fractions. Finely powdered roots of A. adscendens were macerated in methanol and extracted through SPE using gradient solvent system (water: methanol) proceeded for analysis on LC-ESI-QTOF-MS and cytotoxicity against four human carcinoma cell lines: breast (MCF7), liver (HEPG2), lung (A549), and urinary bladder (EJ138), using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromide assay. The MeOH extract and four SPE fractions exhibited cytotoxicity against all cell lines with the IC 50 values ranging from 6 to 79 μg/mL. As observed in other Asparagus species, the presence of saponins and sapogenins in the SPE fractions was evident in the liquid chromatography-mass spectrometry data. It is reasonable to assume that the cytotoxicity of the MeOH extract of the roots of A. adscendens and its SPE fractions, at least partly, due to the presence of saponins and their aglycones. This suggests that A. adscendens could be exploited as a potential source of cytotoxic compounds with putative anticancer potential. The MeOH extract and all solid-phase extraction (SPE) fractions exhibited various levels of cytotoxicity against all cell lines with the IC 50 values ranging from 6 to 79 μg/mLThe presence of saponins and sapogenins in the SPE fractions was evident in the Liquid chromatography-mass spectrometry dataDue to the presence of saponins and their aglycones, suggest that A. adscendens could be exploited as a potential source of cytotoxic compounds with putative anticancer potential. Abbreviation used: SPE: Solid-phase extraction, MCF7: Breast cancer cell line, HEPG2: Liver cancer cell line, A549: Lung liver cancer cell line, EJ138: Urinary bladder cancer cell line, MTT: 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromide, LC-MS: Liquid chromatography-mass spectrometry.

Deposition of corrosion products from dowels on human dental root surfaces measured with proton microprobe technique

NASA Astrophysics Data System (ADS)

Brune, D.; Brunell, G.; Lindh, U.

1982-06-01

Distribution of copper, mercury and zinc on human teeth root surfaces adjacent to dowels of gold alloy or brass as well as dowels of brass in conjunction with an amalgam crown has been measured with a proton microprobe using PIXE techniques. Upper limits of the contents of gold and silver on the root surfaces were established. Pronounced concentration profiles of copper and zinc were observed on the root surfaces of teeth prepared with dowels of brass. The dowel of gold alloy revealed only zinc deposition. The major part of copper on the root surfaces is assumed to arise from corrosion of the dowels, and has been transported to the surface by diffusion through the dential tubuli. Zinc in the volume analysed is a constituent of dentin tissue as well as a corrosion product of the brass dowel. Part of the zinc level could also be ascribed to erosion of the zinc phosphate cement matrix. The volumes analysed were (25×25×25)μm 3. The levels of copper, mercury and zinc on the tooth root surfaces attained values up to about 200, 20 and 600 ppm, respectively.

Thermodynamic control of anvil cloud amount

PubMed Central

Bony, Sandrine; Stevens, Bjorn; Coppin, David; Becker, Tobias; Reed, Kevin A.; Voigt, Aiko

2016-01-01

General circulation models show that as the surface temperature increases, the convective anvil clouds shrink. By analyzing radiative–convective equilibrium simulations, we show that this behavior is rooted in basic energetic and thermodynamic properties of the atmosphere: As the climate warms, the clouds rise and remain at nearly the same temperature, but find themselves in a more stable atmosphere; this enhanced stability reduces the convective outflow in the upper troposphere and decreases the anvil cloud fraction. By warming the troposphere and increasing the upper-tropospheric stability, the clustering of deep convection also reduces the convective outflow and the anvil cloud fraction. When clouds are radiatively active, this robust coupling between temperature, high clouds, and circulation exerts a positive feedback on convective aggregation and favors the maintenance of strongly aggregated atmospheric states at high temperatures. This stability iris mechanism likely contributes to the narrowing of rainy areas as the climate warms. Whether or not it influences climate sensitivity requires further investigation. PMID:27412863

Thermodynamic control of anvil cloud amount

DOE PAGES

Bony, Sandrine; Stevens, Bjorn; Coppin, David; ...

2016-07-13

General circulation models show that as the surface temperature increases, the convective anvil clouds shrink. By analyzing radiative–convective equilibrium simulations, our work shows that this behavior is rooted in basic energetic and thermodynamic properties of the atmosphere: As the climate warms, the clouds rise and remain at nearly the same temperature, but find themselves in a more stable atmosphere; this enhanced stability reduces the convective outflow in the upper troposphere and decreases the anvil cloud fraction. By warming the troposphere and increasing the upper-tropospheric stability, the clustering of deep convection also reduces the convective outflow and the anvil cloud fraction.more » When clouds are radiatively active, this robust coupling between temperature, high clouds, and circulation exerts a positive feedback on convective aggregation and favors the maintenance of strongly aggregated atmospheric states at high temperatures. This stability iris mechanism likely contributes to the narrowing of rainy areas as the climate warms. Whether or not it influences climate sensitivity requires further investigation.« less

Isolation of bergenin from the root bark of Securinega virosa and evaluation of its potential sleep promoting effect.

PubMed

Magaji, Mohammed Garba; Musa, Aliyu Muhammad; Abdullahi, Musa Ismail; Ya'u, Jamilu; Hussaini, Isa Marte

2015-01-01

Securinega virosa Roxb (Ex Willd) Baill (Euphorbaiceae) root bark has been reportedly used in African traditional medicine in the management of mental illnesses. Previously, the sleep-inducing potential of the crude methanol root bark of Securinega virosa extract and its butanol fraction have been reported. The study aimed to isolate and characterize the bioactive constituent that may be responsible for the sleep inducing property of the root of the plant. The phytochemical investigation of the S. virosa root bark was carried out leading to the isolation of a compound from the butanol-soluble fraction of the methanol extract. The structure of the compound was elucidated on the basis of its spectral data, including IR, 1D and 2D NMR, mass spectrometry as well as X-ray diffraction analysis. The compound was investigated for sleep-inducing potential using diazepam-induced sleeping time test and beam walking assay in mice. This is the first report on the isolation of bergenin from the root of the plant. It significantly decreased the mean onset of sleep [F (2, 15) =7.167; p< 0.01] at the dose of 10 mg/kg, without significantly affecting the total sleep duration [F (2, 15) = 0.090, p=0.914]. Conversely, it did not significantly affect the number of foot slips at the doses of 5 and 10 mg/kg tested. Bergenin isolated from the root bark of S. virosa possesses sleep-inducing property and could be partly responsible for the sedative potential of the root of S. virosa.

In vivo microcomputed tomography evaluation of rat alveolar bone and root resorption during orthodontic tooth movement.

PubMed

Ru, Nan; Liu, Sean Shih-Yao; Zhuang, Li; Li, Song; Bai, Yuxing

2013-05-01

To observe the real-time microarchitecture changes of the alveolar bone and root resorption during orthodontic treatment. A 10 g force was delivered to move the maxillary left first molars mesially in twenty 10-week-old rats for 14 days. The first molar and adjacent alveolar bone were scanned using in vivo microcomputed tomography at the following time points: days 0, 3, 7, and 14. Microarchitecture parameters, including bone volume fraction, structure model index, trabecular thickness, trabecular number, and trabecular separation of alveolar bone, were measured on the compression and tension side. The total root volume was measured, and the resorption crater volume at each time point was calculated. Univariate repeated measures analysis of variance with Bonferroni corrections were performed to compare the differences in each parameter between time points with significance level at P < .05. From day 3 to day 7, bone volume fraction, structure model index, trabecular thickness, and trabecular separation decreased significantly on the compression side, but the same parameters increased significantly on the tension side from day 7 to day 14. Root resorption volume of the mesial root increased significantly on day 7 of orthodontic loading. Real-time root and bone resorption during orthodontic movement can be observed in 3 dimensions using in vivo micro-CT. Alveolar bone resorption and root resorption were observed mostly in the apical third on day 7 on the compression side; bone formation was observed on day 14 on the tension side during orthodontic tooth movement.

Surface-based GPR underestimates below-stump root biomass

Treesearch

John R. Butnor; Lisa J. Samuelson; Thomas A. Stokes; Kurt H. Johnsen; Peter H. Anderson; Carlos A. Gonzalez-Benecke

2016-01-01

Aims While lateral root mass is readily detectable with ground penetrating radar (GPR), the roots beneath a tree (below-stump) and overlapping lateral roots near large trees are problematic for surface-based antennas operated in reflection mode. We sought to determine if tree size (DBH) effects GPR root detection proximal to longleaf pine (Pinus palustris Mill) and if...

SMERGE: A multi-decadal root-zone soil moisture product for CONUS

NASA Astrophysics Data System (ADS)

Crow, W. T.; Dong, J.; Tobin, K. J.; Torres, R.

2017-12-01

Multi-decadal root-zone soil moisture products are of value for a range of water resource and climate applications. The NASA-funded root-zone soil moisture merging project (SMERGE) seeks to develop such products through the optimal merging of land surface model predictions with surface soil moisture retrievals acquired from multi-sensor remote sensing products. This presentation will describe the creation and validation of a daily, multi-decadal (1979-2015), vertically-integrated (both surface to 40 cm and surface to 100 cm), 0.125-degree root-zone product over the contiguous United States (CONUS). The modeling backbone of the system is based on hourly root-zone soil moisture simulations generated by the Noah model (v3.2) operating within the North American Land Data Assimilation System (NLDAS-2). Remotely-sensed surface soil moisture retrievals are taken from the multi-sensor European Space Agency Climate Change Initiative soil moisture data set (ESA CCI SM). In particular, the talk will detail: 1) the exponential smoothing approach used to convert surface ESA CCI SM retrievals into root-zone soil moisture estimates, 2) the averaging technique applied to merge (temporally-sporadic) remotely-sensed with (continuous) NLDAS-2 land surface model estimates of root-zone soil moisture into the unified SMERGE product, and 3) the validation of the SMERGE product using long-term, ground-based soil moisture datasets available within CONUS.

Plant regulation of greenhouse gas emissions and carbon lability in a Neotropical peatland

NASA Astrophysics Data System (ADS)

Girkin, Nicholas; Vane, Christopher; Turner, Benjamin; Ostle, Nicholas; Sjogersten, Sofie

2017-04-01

Tropical peatlands are under significant threat from land use changes but there remains a significant knowledge gap regarding the influences of contrasting plant types on greenhouse gas emissions and belowground carbon dynamics. We investigated differences in surface CO2 and CH4 fluxes and differences in soil organic carbon chemistry under contrasting surface vegetation types, a palm (Raphia taedigera) and a broadleaved evergreen tree (Campnosperma panamensis), in a Neotropical peatland. CO2 and CH4 production differed significantly between species, with higher fluxes measured under R. taedigera. There were significant differences in peat carbon properties under each species as revealed by Rock-Eval pyrolysis. Peat from under each species showed contrasting trends in degradation inside and outside the rooting zone, and strong differences in the presence of the most labile fractions of carbon. These results highlight the strong impacts that surface vegetation can have on surface gas emissions as well as the influences exerted on peat carbon chemistry within a tropical forested peatland, with implications for our understanding of changes in land use type across the tropics.

Labile rhizosphere soil solution fraction for prediction of bioavailability of heavy metals and rare earth elements to plants.

PubMed

Shan, Xiao-Quan; Wang, Zhongwen; Wang, Weisheng; Zhang, Shuzhen; Wen, Bei

2003-02-01

A labile rhizosphere soil solution fraction has been recommended to predict the bioavailability of heavy metals and rare earth elements to plants. This method used moist rhizosphere soil in combination with a mixture of 0.01 mol L(-1) of low-molecular-weight organic acids (LMWOAs) as extractant. The extracted soil solutions were fractionated into two colloidal fractions of <0.45 microm (F(3)) and <0.2 microm (F(2)), and one truly dissolved fraction including free metal ions and inorganic and organic complexes (fractionr(0.2 microm, LMWOAs) approximately r(0.45 microm, LMWOAs). In the case of rare earth elements the good correlation was obtained for both the wheat roots and shoots. Generally, the correlation coefficients obtained by LMWAOs were better than that obtained by the first step of BCR method. Therefore, LMWAOs and F(lrss) were strongly recommended to predict the bioavailability of metals in soil pools to plants.

Surface modification of tooth root canal after application of an X-ray opaque waveguide

NASA Astrophysics Data System (ADS)

Dostálová, T.; Jelínková, H.; Šulc, J.; Němec, M.; Koranda, P.; Bartoňová, M.; Radina, P.; Miyagi, M.; Shi, Y.-W.; Matsuura, Y.

The interest in endodontic use of dental laser systems has been increasing. With the development of thin and flexible delivery systems for various wavelengths, laser applications in endodontics may become even more desirable. The aim of this study is to check the X-ray opacity of a hollow waveguide and to observe the results after laser root canal treatment. The root canal systems of 10 molars were treated endodontically by laser. For the laser radiation source, an Er:YAG laser system generating a wavelength of 2940 nm and an Alexandrite laser system generating a wavelength of 375 nm were used. The hollow waveguide used was checked under X-ray . A root canal surface treated by laser radiation was analyzed by a scanning electron microscope (SEM). The special hollow glass waveguide used was visible in the root canal system under X-ray imaging. Surface modification of the root canal after laser treatment was not found. After conventional treatment the root canal was enlarged. The surface was covered with a smear layer. After application of both laser systems, the smear layer was removed. The resulting canal surface was found to be clean and smooth. Under SEM observation open dentinal tubules were visible. No cracks were present, nor were surface modifications observed.

Calculus removal on a root cement surface by ultrashort laser pulses

NASA Astrophysics Data System (ADS)

Kraft, Johan F.; Vestentoft, Kasper; Christensen, Bjarke H.; Løvschall, Henrik; Balling, Peter

2008-01-01

Ultrashort-pulse-laser ablation of dental calculus (tartar) and cement is performed on root surfaces. The investigation shows that the threshold fluence for ablation of calculus is a factor of two to three times smaller than that of a healthy root cement surface. This indicates that ultrashort laser pulses may provide an appropriate tool for selective removal of calculus with minimal damage to the underlying root cement. Future application of an in situ profiling technique allows convenient on-line monitoring of the ablation process.

Twenty Years of Litter and Root Manipulations: Insights into Multi-Decadal SOM Dynamics and Controls

NASA Astrophysics Data System (ADS)

Wig, J.; Lajtha, K.; Nadelhoffer, K. J.

2012-12-01

Reforestation, reducing deforestation, and sustainable forest management are often recommended by policy makers to mitigate the greenhouse gas contributions of the forestry sector. However, underlying many of these policy recommendations is the assumption that increasing above-ground carbon stocks corresponds to long-term increases in ecosystem carbon stocks, the majority of which is stored in soils. We analyzed soil carbon and nitrogen dynamics in forest soils that had undergone twenty years of continuous manipulations of above- and below-ground organic inputs as part of the Detritus Input and Removal Treatment (DIRT) network. Although we expected that increased C inputs would correspond to significantly elevated C in surface mineral soils, our data suggest that increasing above-ground litter inputs has had a positive priming effect in this soil. Positive priming occurs when increased rates of litter addition to soil lead to disproportionate increases in microbial respiration rates of native soil C, resulting in a net decrease of soil C. Soil respiration rates in a year-long laboratory incubation support this theory: increased above-ground litter inputs led to decreased respiration rates, suggesting a relative deficit of labile organic matter. Removal of below ground inputs, either with or without above-ground litter inputs, also led to decreased respiration in laboratory incubations, demonstrating the importance of fresh root inputs to labile C. Trends in non-hydrolyzable C fractions, a proxy for the more stable C pool, agree with our respiration measurements. Data from sequential density fractionation are consistent with the hypotheses that priming has occurred in response to increased above-ground litter inputs and that root inputs are an important control of the labile C pool. The importance of roots inputs for C stabilization is well documented in the literature, and our hypothesis that increased above-ground litter inputs leads to priming is supported by data from several other DIRT sites. These data indicate there is an important potential loss of ecosystem C due to priming which should be considered when changing organic inputs to the soil, as is the case in some sustainable forestry recommendations.

Changes in plastid proteome and structure in arbuscular mycorrhizal roots display a nutrient starvation signature.

PubMed

Daher, Zeina; Recorbet, Ghislaine; Solymosi, Katalin; Wienkoop, Stefanie; Mounier, Arnaud; Morandi, Dominique; Lherminier, Jeannine; Wipf, Daniel; Dumas-Gaudot, Eliane; Schoefs, Benoît

2017-01-01

During arbuscular mycorrhizal symbiosis, arbuscule-containing root cortex cells display a proliferation of plastids, a feature usually ascribed to an increased plant anabolism despite the lack of studies focusing on purified root plastids. In this study, we investigated mycorrhiza-induced changes in plastidic pathways by performing a label-free comparative subcellular quantitative proteomic analysis targeted on plastid-enriched fractions isolated from Medicago truncatula roots, coupled to a cytological analysis of plastid structure. We identified 490 root plastid protein candidates, among which 79 changed in abundance upon mycorrhization, as inferred from spectral counting. According to cross-species sequence homology searches, the mycorrhiza-responsive proteome was enriched in proteins experimentally localized in thylakoids, whereas it was depleted of proteins ascribed predominantly to amyloplasts. Consistently, the analysis of plastid morphology using transmission electron microscopy indicated that starch depletion associated with the proliferation of membrane-free and tubular membrane-containing plastids was a feature specific to arbusculated cells. The loss of enzymes involved in carbon/nitrogen assimilation and provision of reducing power, coupled to macromolecule degradation events in the plastid-enriched fraction of mycorrhizal roots that paralleled lack of starch accumulation in arbusculated cells, lead us to propose that arbuscule functioning elicits a nutrient starvation and an oxidative stress signature that may prime arbuscule breakdown. © 2016 Scandinavian Plant Physiology Society.

The effect of MTAD, an endodontic irrigant, on fibroblast attachment to periodontally affected root surfaces: A SEM analysis.

PubMed

Ghandi, Mostafa; Houshmand, Behzad; Nekoofar, Mohammad H; Tabor, Rachel K; Yadeghari, Zahra; Dummer, Paul M H

2013-03-01

Root surface debridement (RSD) is necessary to create an environment suitable for reattachment of the periodontium. Root surface conditioning may aid the formation of a biocompatible surface suitable for cell reattachment. BioPure™ MTAD (mixture of Doxycycline, citric acid and a detergent) is an endodontic irrigant with antibacterial properties and the ability to remove smear layer. It was hypothesized that MTAD may be useful for root surface conditioning. The efficacy of MTAD as a conditioner was measured by examining fibroblast attachment to root surfaces. Thirty-two specimens of human teeth with advanced periodontal disease were used. The surfaces were root planed until smooth. Half of the specimens were treated with 0.9% saline and the other samples with Biopure MTAD. As a negative control group, five further samples were left unscaled with surface calculus. Human gingival fibroblast cells HGF1-PI1 were cultured and poured over the tooth specimens and incubated. After fixation, the samples were sputter-coated with gold and examined with a SEM. The morphology and number of attached, fixed viable cells were examined. The data was analysed using the Mann-Whitney-U statistical test. There was no significant difference between the numbers of attached cells in the experimental group treated with MTAD and the control group treated with saline. Little or no attached cells were seen in the negative control group. RSD created an environment suitable for cell growth and attachment in a laboratory setting. The use of MTAD did not promote the attachment and growth of cells on the surface of human roots following RSD.

Controls on deep drainage beneath the root soil zone in snowmelt-dominated environments

NASA Astrophysics Data System (ADS)

Hammond, J. C.; Harpold, A. A.; Kampf, S. K.

2017-12-01

Snowmelt is the dominant source of streamflow generation and groundwater recharge in many high elevation and high latitude locations, yet we still lack a detailed understanding of how snowmelt is partitioned between the soil, deep drainage, and streamflow under a variety of soil, climate, and snow conditions. Here we use Hydrus 1-D simulations with historical inputs from five SNOTEL snow monitoring sites in each of three regions, Cascades, Sierra, and Southern Rockies, to investigate how inter-annual variability on water input rate and duration affects soil saturation and deep drainage. Each input scenario was run with three different soil profiles of varying hydraulic conductivity, soil texture, and bulk density. We also created artificial snowmelt scenarios to test how snowmelt intermittence affects deep drainage. Results indicate that precipitation is the strongest predictor (R2 = 0.83) of deep drainage below the root zone, with weaker relationships observed between deep drainage and snow persistence, peak snow water equivalent, and melt rate. The ratio of deep drainage to precipitation shows a stronger positive relationship to melt rate suggesting that a greater fraction of input becomes deep drainage at higher melt rates. For a given amount of precipitation, rapid, concentrated snowmelt may create greater deep drainage below the root zone than slower, intermittent melt. Deep drainage requires saturation below the root zone, so saturated hydraulic conductivity serves as a primary control on deep drainage magnitude. Deep drainage response to climate is mostly independent of soil texture because of its reliance on saturated conditions. Mean water year saturations of deep soil layers can predict deep drainage and may be a useful way to compare sites in soils with soil hydraulic porosities. The unit depth of surface runoff often is often greater than deep drainage at daily and annual timescales, as snowmelt exceeds infiltration capacity in near-surface soil layers. These results suggest that processes affecting the duration of saturation below the root zone could compromise deep recharge, including changes in snowmelt rate and duration as well as the depth and rate of ET losses from the soil profile.

8,12;8,20-diepoxy-8,14-secopregnane glycosides from roots of Asclepias tuberosa and their effect on proliferation of human skin fibroblasts.

PubMed

Warashina, Tsutomu; Umehara, Kaoru; Miyase, Toshio; Noro, Tadataka

2011-10-01

A pregnane glycoside fraction from the roots of Asclepias tuberosa L. caused normal human skin fibroblasts to proliferate. This fraction contained 21 pregnane glycosides whose structures were established using NMR spectroscopic analysis and chemical evidence. The aglycones of most of these compounds were identified as 8,12;8,20-diepoxy-8,14-secopregnanes, such as tuberogenin or 5,6-didehydrotuberogenin, the same aglycones as constituents of the aerial parts of this plant. Some of these compounds also caused proliferation of skin fibroblasts. Copyright © 2011 Elsevier Ltd. All rights reserved.

Role of Subsurface Physics in the Assimilation of Surface Soil Moisture Observations

NASA Technical Reports Server (NTRS)

Reichle, R. H.

2010-01-01

Root zone soil moisture controls the land-atmosphere exchange of water and energy and exhibits memory that may be useful for climate prediction at monthly scales. Assimilation of satellite-based surface soil moisture observations into a land surface model is an effective way to estimate large-scale root zone soil moisture. The propagation of surface information into deeper soil layers depends on the model-specific representation of subsurface physics that is used in the assimilation system. In a suite of experiments we assimilate synthetic surface soil moisture observations into four different models (Catchment, Mosaic, Noah and CLM) using the Ensemble Kalman Filter. We demonstrate that identical twin experiments significantly overestimate the information that can be obtained from the assimilation of surface soil moisture observations. The second key result indicates that the potential of surface soil moisture assimilation to improve root zone information is higher when the surface to root zone coupling is stronger. Our experiments also suggest that (faced with unknown true subsurface physics) overestimating surface to root zone coupling in the assimilation system provides more robust skill improvements in the root zone compared with underestimating the coupling. When CLM is excluded from the analysis, the skill improvements from using models with different vertical coupling strengths are comparable for different subsurface truths. Finally, the skill improvements through assimilation were found to be sensitive to the regional climate and soil types.

High-order fractional partial differential equation transform for molecular surface construction

PubMed Central

Hu, Langhua; Chen, Duan; Wei, Guo-Wei

2013-01-01

Fractional derivative or fractional calculus plays a significant role in theoretical modeling of scientific and engineering problems. However, only relatively low order fractional derivatives are used at present. In general, it is not obvious what role a high fractional derivative can play and how to make use of arbitrarily high-order fractional derivatives. This work introduces arbitrarily high-order fractional partial differential equations (PDEs) to describe fractional hyperdiffusions. The fractional PDEs are constructed via fractional variational principle. A fast fractional Fourier transform (FFFT) is proposed to numerically integrate the high-order fractional PDEs so as to avoid stringent stability constraints in solving high-order evolution PDEs. The proposed high-order fractional PDEs are applied to the surface generation of proteins. We first validate the proposed method with a variety of test examples in two and three-dimensional settings. The impact of high-order fractional derivatives to surface analysis is examined. We also construct fractional PDE transform based on arbitrarily high-order fractional PDEs. We demonstrate that the use of arbitrarily high-order derivatives gives rise to time-frequency localization, the control of the spectral distribution, and the regulation of the spatial resolution in the fractional PDE transform. Consequently, the fractional PDE transform enables the mode decomposition of images, signals, and surfaces. The effect of the propagation time on the quality of resulting molecular surfaces is also studied. Computational efficiency of the present surface generation method is compared with the MSMS approach in Cartesian representation. We further validate the present method by examining some benchmark indicators of macromolecular surfaces, i.e., surface area, surface enclosed volume, surface electrostatic potential and solvation free energy. Extensive numerical experiments and comparison with an established surface model indicate that the proposed high-order fractional PDEs are robust, stable and efficient for biomolecular surface generation. PMID:24364020

Ultramorphology of the root surface subsequent to hand-ultrasonic simultaneous instrumentation during non-surgical periodontal treatments. An in vitro study

PubMed Central

D. ASPRIELLO, Simone; PIEMONTESE, Matteo; LEVRINI, Luca; SAURO, Salvatore

2011-01-01

Objective The purpose of this study was to investigate the ultramorphology of the root surfaces induced by mechanical instrumentation performed using conventional curettes or piezoelectric scalers when used single-handedly or with a combined technique. Material and Methods Thirty single-rooted teeth were selected and divided into 3 groups: Group A, instrumentation with curettes; Group B instrumentation with titanium nitride coated periodontal tip mounted in a piezoelectric handpiece; Group C, combined technique with curette/ultrasonic piezoelectric instrumentation. The specimens were processed and analyzed using confocal and scanning electron microscopy. Differences between the different groups of instrumentation were determined using Pearson’s χ 2 with significance predetermined at α=0.001. Results Periodontal scaling and root planing performed with curettes, ultrasonic or combined instrumentation induced several morphological changes on the root surface. The curettes produced a compact and thick multilayered smear layer, while the morphology of the root surfaces after ultrasonic scaler treatment appeared irregular with few grooves and a thin smear layer. The combination of curette/ultrasonic instrumentation showed exposed root dentin tubules with a surface morphology characterized by the presence of very few grooves and slender remnants of smear layer which only partially covered the root dentin. In some cases, it was also possible to observe areas with exposed collagen fibrils. Conclusion The curette-ultrasonic simultaneous instrumentation may combine the beneficial effects of each instrument in a single technique creating a root surface relatively free from the physical barrier of smear layer and dentin tubules orifices partial occlusion. PMID:21437474

Effect of citric acid, tetracycline, and doxycycline on instrumented periodontally involved root surfaces: A SEM study

PubMed Central

Chahal, Gurparkash Singh; Chhina, Kamalpreet; Chhabra, Vipin; Bhatnagar, Rakhi; Chahal, Amna

2014-01-01

Background: A surface smear layer consisting of organic and inorganic material is formed on the root surface following mechanical instrumentation and may inhibit the formation of new connective tissue attachment to the root surface. Modification of the tooth surface by root conditioning has resulted in improved connective tissue attachment and has advanced the goal of reconstructive periodontal treatment. Aim: The aim of this study was to compare the effects of citric acid, tetracycline, and doxycycline on the instrumented periodontally involved root surfaces in vitro using a scanning electron microscope. Settings and Design: A total of 45 dentin samples obtained from 15 extracted, scaled, and root planed teeth were divided into three groups. Materials and Methods: The root conditioning agents were applied with cotton pellets using the Passive burnishing technique for 5 minutes. The samples were then examined by the scanning electron microscope. Statistical Analysis Used: The statistical analysis was carried out using Statistical Package for Social Sciences (SPSS Inc., Chicago, IL, version 15.0 for Windows). For all quantitative variables means and standard deviations were calculated and compared. For more than two groups ANOVA was applied. For multiple comparisons post hoc tests with Bonferroni correction was used. Results: Upon statistical analysis the root conditioning agents used in this study were found to be effective in removing the smear layer, uncovering and widening the dentin tubules and unmasking the dentin collagen matrix. Conclusion: Tetracycline HCl was found to be the best root conditioner among the three agents used. PMID:24744541

Clinical evaluation of demineralization and remineralization of intact root surface lesions in the clinic by a quantitative light-induced fluorescence system.

PubMed

Durmusoglu, Oykü; Tağtekin, Dilek Arslantunali; Yanikoğlu, Funda

2012-03-01

Detection of demineralization of root surface caries is an important issue since preventive approaches prolong tooth life. Quantitative light-induced fluorescence (QLF) has been shown to be useful for the laboratory assessment of demineralization of root surfaces. The aim of this study was to determine the demineralization and remineralization of root surface intact and cavitated caries lesions using a QLF system as a nondestructive in vivo method. Noncavitated and demineralized root surface lesions were detected and scored using the QLF system. Oral hygiene education was given and periodontal cleaning was completed before the remineralization treatment. After obtaining baseline QLF data, the patients were informed about the remineralization treatment. Fluoride varnish was applied to the carious lesions at the baseline visit, and the patients were then reviewed after 1, 2, 3 and 4 weeks, with QLF assessment and fluoride varnish application repeated at each review. Repeated-measures ANOVA (α = 0.05) showed significant differences between ΔQ values at each visit (p < 0.001); ΔQ showed marked decreases at all the cut-off values (15, 20, 25, 30). The changes in ΔQ were not affected by the cut-off value. The ΔQ values of QLF showed differences at all visits. The QLF system was able to detect early root surface caries lesions in vivo. Bifluoride 12 varnish improved mineral levels as shown by the QLF system. The treatment response to chemicals of intact noncavitated root surface carious lesions could be followed nondestructively in the clinic using QLF to quantify remineralization at recall visits. Teeth with root surface caries can be kept by controlling their remineralization.

Apical root resorption during orthodontic treatment. A prospective study using cone beam CT.

PubMed

Lund, Henrik; Gröndahl, Kerstin; Hansen, Ken; Gröndahl, Hans-Göran

2012-05-01

To investigate the incidence and severity of root resorption during orthodontic treatment by means of cone beam computed tomography (CBCT) and to explore factors affecting orthodontically induced inflammatory root resorption (OIIRR). CBCT examinations were performed on 152 patients with Class I malocclusion. All roots from incisors to first molars were assessed on two or three occasions. At treatment end, 94% of patients had ≥1 root with shortening >1 mm, and 6.6% had ≥1 tooth where it exceeded 4 mm. Among teeth, 56.3% of upper lateral incisors had root shortening >1 mm. Of upper incisors and the palatal root of upper premolars, 2.6% showed root shortenings >4 mm. Slanted surface resorptions of buccal and palatal surfaces were found in 15.1% of upper central and 11.5% of lateral incisors. Monthly root shortening was greater after 6-month control than before. Upper jaw teeth and anterior teeth were significantly associated with the degree of root shortening. Gender, root length at baseline, and treatment duration were not. Practically all patients and up to 91% of all teeth showed some degree of root shortening, but few patients and teeth had root shortenings >4 mm. Slanted root resorption was found on root surfaces that could be evaluated only by a tomographic technique. A CBCT technique can provide more valid and accurate information about root resorption.

Influences of calcium availability and tree species on Ca isotope fractionation in soil and vegetation

USGS Publications Warehouse

Page, B.D.; Bullen, T.D.; Mitchell, M.J.

2008-01-01

The calcium (Ca) isotope system is potentially of great use for understanding biogeochemical processes at multiple scales in forest ecosystems, yet remains largely unexplored for this purpose. In order to further our understanding of Ca behavior in forests, we examined two nearly adjacent hardwood-dominated catchments with differing soil Ca concentrations, developed from crystalline bedrock, to determine the variability of 44Ca/ 40Ca ratios (expressed as ??44Ca) within soil and vegetation pools. For both sugar maple and American beech, the Ca isotope compositions of the measured roots and calculated bulk trees were considerably lighter than those of soil pools at these sites, suggesting that the trees were able to preferentially take up light Ca at the root-soil interface. The Ca isotope compositions of three of four root samples were among the lightest values yet reported for terrestrial materials (??44Ca ???-3.95???). Our results further indicate that Ca isotopes were fractionated along the transpiration streams of both tree species with roots having the least ??44Ca values and leaf litter the greatest. An approximately 2??? difference in ??44Ca values between roots and leaf litter of both tree species suggests a persistent fractionation mechanism along the transpiration stream, likely related to Ca binding in wood tissue coupled with internal ion exchange. Finally, our data indicate that differing tree species demand for Ca and soil Ca concentrations together may influence Ca isotope distribution within the trees. Inter-catchment differences in Ca isotope distributions in soils and trees were minor, indicating that the results of our study may have broad transferability to studies of forest ecosystems in catchments developed on crystalline substrates elsewhere. ?? 2008 Springer Science+Business Media B.V.

Effects of tungsten on uptake, transport and subcellular distribution of molybdenum in oilseed rape at two different molybdenum levels.

PubMed

Qin, Shiyu; Sun, Xuecheng; Hu, Chengxiao; Tan, Qiling; Zhao, Xiaohu; Xu, Shoujun

2017-03-01

Due to the similarities of molybdenum (Mo) with tungsten (W) in the physical structure and chemical properties, studies involving the two elements have mainly examined their competitive relationships. The objectives of this study were to assess the effects of equimolar W on Mo accumulation, transport and subcellular distribution in oilseed rape at two Mo levels with four treatments: Mo 1 (1μmol/L Mo, Low Mo), Mo 1 +W 1 (1μmol/L Mo+1μmol/LW, Low Mo with Low W), Mo 200 (200μmol/L Mo, High Mo) and Mo 200 +W 200 (200μmol/L Mo+200μmol/L Mo, High Mo with high W). The fresh weight and root growth were inhibited by equimolar W at both low and high Mo levels. The Mo concentration and accumulation in root was increased by equimolar W at the low Mo level, but that in the root and shoot was decreased at the high Mo level. Additionally, equimolar W increased the Mo concentrations of xylem and phloem sap at low Mo level, but decreased that of xylem and increased that of phloem sap at the high Mo level. Furthermore, equimolar W decreased the expression of BnMOT1 in roots and leaves at the low Mo level, and only decreased its expression in leaves at the high Mo level. The expression of BnMOT2 was also decreased in root for equimolar W compared with the low Mo level, but increased compared with high Mo level. Moreover, equimolar W increased the proportion of Mo in cell wall fraction in root and that of soluble fraction in leaves when compared with the low Mo level. The results suggest that cell wall and soluble fractions might be responsible for the adaptation of oilseed rape to W stress. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Do root hydraulic properties change during the early vegetative stage of plant development in barley (Hordeum vulgare)?

PubMed Central

Suku, Shimi; Knipfer, Thorsten; Fricke, Wieland

2014-01-01

Background and Aims As annual crops develop, transpirational water loss increases substantially. This increase has to be matched by an increase in water uptake through the root system. The aim of this study was to assess the contributions of changes in intrinsic root hydraulic conductivity (Lp, water uptake per unit root surface area, driving force and time), driving force and root surface area to developmental increases in root water uptake. Methods Hydroponically grown barley plants were analysed during four windows of their vegetative stage of development, when they were 9–13, 14–18, 19–23 and 24–28 d old. Hydraulic conductivity was determined for individual roots (Lp) and for entire root systems (Lpr). Osmotic Lp of individual seminal and adventitious roots and osmotic Lpr of the root system were determined in exudation experiments. Hydrostatic Lp of individual roots was determined by root pressure probe analyses, and hydrostatic Lpr of the root system was derived from analyses of transpiring plants. Key Results Although osmotic and hydrostatic Lp and Lpr values increased initially during development and were correlated positively with plant transpiration rate, their overall developmental increases (about 2-fold) were small compared with increases in transpirational water loss and root surface area (about 10- to 40-fold). The water potential gradient driving water uptake in transpiring plants more than doubled during development, and potentially contributed to the increases in plant water flow. Osmotic Lpr of entire root systems and hydrostatic Lpr of transpiring plants were similar, suggesting that the main radial transport path in roots was the cell-to-cell path at all developmental stages. Conclusions Increase in the surface area of root system, and not changes in intrinsic root hydraulic properties, is the main means through which barley plants grown hydroponically sustain an increase in transpirational water loss during their vegetative development. PMID:24287810

Do root hydraulic properties change during the early vegetative stage of plant development in barley (Hordeum vulgare)?

PubMed

Suku, Shimi; Knipfer, Thorsten; Fricke, Wieland

2014-02-01

As annual crops develop, transpirational water loss increases substantially. This increase has to be matched by an increase in water uptake through the root system. The aim of this study was to assess the contributions of changes in intrinsic root hydraulic conductivity (Lp, water uptake per unit root surface area, driving force and time), driving force and root surface area to developmental increases in root water uptake. Hydroponically grown barley plants were analysed during four windows of their vegetative stage of development, when they were 9-13, 14-18, 19-23 and 24-28 d old. Hydraulic conductivity was determined for individual roots (Lp) and for entire root systems (Lp(r)). Osmotic Lp of individual seminal and adventitious roots and osmotic Lp(r) of the root system were determined in exudation experiments. Hydrostatic Lp of individual roots was determined by root pressure probe analyses, and hydrostatic Lp(r) of the root system was derived from analyses of transpiring plants. Although osmotic and hydrostatic Lp and Lp(r) values increased initially during development and were correlated positively with plant transpiration rate, their overall developmental increases (about 2-fold) were small compared with increases in transpirational water loss and root surface area (about 10- to 40-fold). The water potential gradient driving water uptake in transpiring plants more than doubled during development, and potentially contributed to the increases in plant water flow. Osmotic Lp(r) of entire root systems and hydrostatic Lp(r) of transpiring plants were similar, suggesting that the main radial transport path in roots was the cell-to-cell path at all developmental stages. Increase in the surface area of root system, and not changes in intrinsic root hydraulic properties, is the main means through which barley plants grown hydroponically sustain an increase in transpirational water loss during their vegetative development.

Effect of surface treatment of fiberglass posts on bond strength to root dentin.

PubMed

Valdivia, Andréa Dolores Correia Miranda; Novais, Veridiana Resende; Menezes, Murilo de Sousa; Roscoe, Marina Guimarães; Estrela, Carlos; Soares, Carlos José

2014-01-01

This study evaluated the influence of the surface treatments of fiberglass posts on bond strength to root dentin using push-out test. Forty bovine incisor roots were endodontically treated. The surface of the fiberglass posts (Exacto #2, Angelus) were treated using 4 different protocols (n=10): Control - 70% ethanol for 1 min; 37% phosphoric acid for 1 min; 10% hydrofluoric acid for 1 min; and 24% hydrogen peroxide for 1 min. After a silane coupling agent was applied for 1 min and all posts were cemented using self-adhesive resin cement (RelyX Unicem, 3M-ESPE). The roots were sectioned and two 1-mm-thick slices were obtained from each third: cervical, middle and apical. The specimens were subjected to the push-out test with a crosshead speed of 0.5 mm/min. Data were analyzed by repeated measures ANOVA followed by Tukey's HSD tests (=0.05). The surface treatment (p<0.001) and root third region (p=0.007) factors were significant. The retention to root canal was affected by surface treatment type. The post surface treatment with 24% hydrogen peroxide for 1 min yielded significantly higher bond strength when the fiberglass posts were cemented with RelyX Unicem.

Does the increased air humidity affect soil respiration and carbon stocks?

NASA Astrophysics Data System (ADS)

Kukumägi, Mai; Celi, Luisella; Said-Pullicino, Daniel; Kupper, Priit; Sõber, Jaak; Lõhmus, Krista; Kutti, Sander; Ostonen, Ivika

2013-04-01

Climate manipulation experiments at ecosystem-scale enable us to simulate, investigate and predict changes in carbon balance of forest ecosystems. Considering the predicted increase in air humidity and precipitation for northern latitudes, this work aimed at investigating the effect of increased air humidity on soil respiration, distribution of soil organic matter (SOM) among pools having different turnover times, and microbial, fine root and rhizome biomass. The study was carried out in silver birch (Betula pendula Roth.) and hybrid aspen (Populus tremula L. × P. tremuloides Michx.) stands in a Free Air Humidity Manipulation (FAHM) experimental facility containing three humidified (H; on average 7% above current ambient levels since 2008) and three control (C) plots. Soil respiration rates were measured monthly during the growing season using a closed dynamic chamber method. Density fractionation was adopted to separate SOM into two light fractions (free and aggregate-occluded particulate organic matter, fPOM and oPOM respectively), and one heavy fraction (mineral-associated organic matter, MOM). The fine root and rhizome biomass and microbial data are presented for silver birch stands only. In 2011, after 4 growing seasons of humidity manipulation soil organic carbon contents were significantly higher in C plots than H plot (13.5 and 12.5 g C kg-1, respectively), while soil respiration tended to be higher in the latter. Microbial biomass and basal respiration were 13 and 14% higher in H plots than in the C plots, respectively. Twice more fine roots of trees were estimated in H plots, while the total fine root and rhizome biomass (tree + understory) was similar in C and H plots. Fine root turnover was higher for both silver birch and understory roots in H plots. Labile SOM light fractions (fPOM and oPOM) were significantly smaller in H plots with respect to C plots (silver birch and hybrid aspen stands together), whereas no differences were observed in the contents of the more stable MOM. These results strongly suggest that, apart from the predicted increase in temperature and atmospheric carbon and nitrogen concentrations, an increase in free air humidity as a result of climate change may significantly influence the complex belowground carbon cycling by affecting biomass production, soil respiration and organic matter turnover.

Natural history and outcome of aortic stenosis diagnosed prenatally.

PubMed Central

Simpson, J. M.; Sharland, G. K.

1997-01-01

OBJECTIVE: To document the growth of the left heart structures and outcome of fetuses with aortic stenosis. DESIGN: Retrospective echocardiographic and clinical study. SETTING: Tertiary centre for fetal cardiology. PATIENTS: 27 consecutive fetuses with aortic stenosis. MAIN OUTCOME MEASURES: Survival of affected fetuses. Measurement of left ventricular end diastolic volume (LVEDV), aortic root diameter, and ejection fraction. RESULTS: Before 25 weeks' gestation, the LVEDV was normal or increased in all cases. In six of eight fetuses studied sequentially, the LVEDV fell across normal centiles. Initial ejection fraction was reduced in 23 fetuses (88%). Before 28 weeks' gestation, the aortic root was normal in all but one case, but after 29 weeks, 11 of 13 fetuses had values below the 50th centile. In two fetuses prenatal aortic valvoplasty was attempted, 10 babies had postnatal interventions, and there were six survivors. Biventricular repair was attempted in eight cases, of whom five survived. A first stage Norwood operation was performed in three babies, of whom one survived. The four fetuses with the highest aortic root z scores had successful biventricular repair. The two fetuses with initially normal ejection fractions survived. Successful biventricular repair was achieved even where the LVEDV was below the 5th centile. CONCLUSIONS: In aortic stenosis diagnosed prenatally, failure of growth of the left ventricle and aortic root often occurs. The outcome of affected fetuses is better than previously reported. Prenatal echocardiography may assist selection of suitable candidates for biventricular versus Norwood repair. Images PMID:9093035

A bioactivity guided study on the antibacterial activity of Hertia cheirifolia L. extracts.

PubMed

Majouli, Kaouther; Hamdi, Assia; Msaada, Kamel; Kenani, Abderraouf

2017-05-01

This study was carried out with the objective to investigate the antibacterial activity of Hertia cheirifolia L. extracts against Gram-positive and Gram-negative strains including Staphylococcus aureus (ATCC 6538), Bacillus subtilis (ATCC 6633), Bacillus licheniformis, Esherichia coli (ATCC 8739), Pseudomonas aeruginosa (ATCC 9027), Salmonella enterica (CIP 8039) and Salmonella typhimirium. The results of this antibacterial screening showed that the ethyl acetate (EtOAc) extracts had the best activity against the tested microorganisms. A bioassay-oriented fractionation approach for the more active extract (roots ethyl acetate extract) led to the obtaining five sub-fractions. Furthermore, these sub-fractions were also tested for antimicrobial activity and the best results were obtained for the roots EtOAc sub-fraction (C) with MICs values between 0.039 and 0.156 mg/mL. Reversed-phase high performance liquid chromatography (RP-HPLC) analysis indicated that the major phenolic components of active (EtOAc) extracts and sub-fraction (C) are fisetin hydrate (82.06%), trans cinnamic acid (63.66%), gallic acid (38.97%) and myricetin (20.92%). These results may help to improve these natural antibacterial substances that could serve as selective agents for bacterial diseases. Copyright © 2016 Elsevier Ltd. All rights reserved.

Extracts and Fractions from Edible Roots of Sechium edule (Jacq.) Sw. with Antihypertensive Activity

PubMed Central

Lombardo-Earl, Galia; Roman-Ramos, Rubén; Zamilpa, Alejandro; Herrera-Ruiz, Maribel; Rosas-Salgado, Gabriela; Tortoriello, Jaime; Jiménez-Ferrer, Enrique

2014-01-01

Sechium edule is traditionally used in Mexico as a therapeutic resource against renal diseases and to control high blood pressure. The purpose of this work is to evaluate the antihypertensive effect of the hydroalcoholic extract obtained from the roots of this plant, including its fractions and subfractions, on different hypertension models induced with angiotensin II (AG II). The hydroalcoholic extract was tested on an in vitro study of isolated aorta rings denuded of endothelial cells, using AG II as the agonist; this assay proved the vasorelaxant effect of this extract. Vagotomized rats were administered different doses of AG II as well as the Hydroalcoholic extract, which reduced blood pressure in 30 mmHg approximately; subsequently this extract was separated into two fractions (acetone and methanol) which were evaluated in the acute hypertension mouse model induced with AG II, where the acetone fraction was identified as the most effective one and was subsequently subfractioned using an open chromatographic column packed with silica gel. The subfractions were also evaluated in the acute hypertension model. Finally, the extract, fraction, and active subfraction were analyzed by MS-PDA-HPLC, identifying cinnamic derivative compounds like cinnamic acid methyl ester. PMID:24812568

Morphological changes in diseased cementum layers: a scanning electron microscopy study.

PubMed

Bilgin, E; Gürgan, C A; Arpak, M Nejat; Bostanci, H S; Güven, K

2004-05-01

The aim of this study was to compare the morphological changes that occurred in root cementum layers due to periodontal disease by using scanning electron microscopy (SEM). Ninety-two periodontally hopeless teeth extracted from 29 patients were studied. Measurements of probing depth (PD) and clinical attachment loss (CAL) were taken prior to extractions. After the longitudinal fracturing process of root specimens, healthy and diseased cementum layers of roots were evaluated by SEM for the thickness of the cementum and the morphological changes in collagen fibers. The result of SEM evaluation revealed a significant ( P < 0.001) decrease in the thickness of cementum layer on the diseased root surfaces compared to the healthy surfaces. There were denser and conspicuous collagen fibers with their interfibrillar matrix in cementum layers on the healthy root surfaces compared to the diseased surfaces. Within the limits of this study, the thickness of cementum layers in diseased areas was found to be significantly less than that in the healthy areas of root surfaces. However, there exist variations in the density and visibility of cemental fibers between individuals and within the individual.

Inhibition of nitrate transport by anti-nitrate reductase IgG fragments and the identification of plasma membrane associated nitrate reductase in roots of barley seedlings

NASA Technical Reports Server (NTRS)

Ward, M. R.; Tischner, R.; Huffaker, R. C.

1988-01-01

Membrane associated nitrate reductase (NR) was detected in plasma membrane (PM) fractions isolated by aqueous two-phase partitioning from barley (Hordeum vulgare L. var CM 72) roots. The PM associated NR was not removed by washing vesicles with 500 millimolar NaCl and 1 millimolar EDTA and represented up to 4% of the total root NR activity. PM associated NR was stimulated up to 20-fold by Triton X-100 whereas soluble NR was only increased 1.7-fold. The latency was a function of the solubilization of NR from the membrane. NR, solubilized from the PM fraction by Triton X-100 was inactivated by antiserum to Chlorella sorokiniana NR. Anti-NR immunoglobulin G fragments purified from the anti-NR serum inhibited NO3- uptake by more than 90% but had no effect on NO2- uptake. The inhibitory effect was only partially reversible; uptake recovered to 50% of the control after thorough rinsing of roots. Preimmune serum immunoglobulin G fragments inhibited NO3- uptake 36% but the effect was completely reversible by rinsing. Intact NR antiserum had no effect on NO3- uptake. The results present the possibility that NO3- uptake and NO3- reduction in the PM of barley roots may be related.

In Vitro Adhesion of Streptococcus sanguinis to Dentine Root Surface After Treatment with Er:Yag Laser, Ultrasonic System, or Manual Curette

PubMed Central

Martins, Fernanda L.; Giorgetti, Ana Paula O.; de Freitas, Patrícia M.; Duarte, Poliana M.

2009-01-01

Abstract Objective: The purpose of this in vitro study was to evaluate the dentine root surface roughness and the adherence of Streptococcus sanguinis (ATCC 10556) after treatment with an ultrasonic system, Er:YAG laser, or manual curette. Background Data: Bacterial adhesion and formation of dental biofilm after scaling and root planing may be a challenge to the long-term stability of periodontal therapy. Materials and Methods: Forty flattened bovine roots were randomly assigned to one of the following groups: ultrasonic system (n = 10); Er:YAG laser (n = 10); manual curette (n = 10); or control untreated roots (n = 10). The mean surface roughness (Ra, μm) of the specimens before and after exposure to each treatment was determined using a surface profilometer. In addition, S. sanguinis was grown on the treated and untreated specimens and the amounts of retained bacteria on the surfaces were measured by culture method. Results: All treatments increased the Ra; however, the roughest surface was produced by the curettes. In addition, the specimens treated with curettes showed the highest S. sanguinis adhesion. There was a significant positive correlation between roughness values and bacterial cells counts. Conclusion: S. sanguinis adhesion was the highest on the curette-treated dentine root surfaces, which also presented the greatest surface roughness. PMID:19712018

ForCent model development and testing using the Enriched Background Isotope Study experiment

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

Parton, W.J.; Hanson, P. J.; Swanston, C.

The ForCent forest ecosystem model was developed by making major revisions to the DayCent model including: (1) adding a humus organic pool, (2) incorporating a detailed root growth model, and (3) including plant phenological growth patterns. Observed plant production and soil respiration data from 1993 to 2000 were used to demonstrate that the ForCent model could accurately simulate ecosystem carbon dynamics for the Oak Ridge National Laboratory deciduous forest. A comparison of ForCent versus observed soil pool {sup 14}C signature ({Delta} {sup 14}C) data from the Enriched Background Isotope Study {sup 14}C experiment (1999-2006) shows that the model correctly simulatesmore » the temporal dynamics of the {sup 14}C label as it moved from the surface litter and roots into the mineral soil organic matter pools. ForCent model validation was performed by comparing the observed Enriched Background Isotope Study experimental data with simulated live and dead root biomass {Delta} {sup 14}C data, and with soil respiration {Delta} {sup 14}C (mineral soil, humus layer, leaf litter layer, and total soil respiration) data. Results show that the model correctly simulates the impact of the Enriched Background Isotope Study {sup 14}C experimental treatments on soil respiration {Delta} {sup 14}C values for the different soil organic matter pools. Model results suggest that a two-pool root growth model correctly represents root carbon dynamics and inputs to the soil. The model fitting process and sensitivity analysis exposed uncertainty in our estimates of the fraction of mineral soil in the slow and passive pools, dissolved organic carbon flux out of the litter layer into the mineral soil, and mixing of the humus layer into the mineral soil layer.« less

ForCent Model Development and Testing using the Enriched Background Isotope Study (EBIS) Experiment

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

Parton, William; Hanson, Paul J; Swanston, Chris

The ForCent forest ecosystem model was developed by making major revisions to the DayCent model including: (1) adding a humus organic pool, (2) incorporating a detailed root growth model, and (3) including plant phenological growth patterns. Observed plant production and soil respiration data from 1993 to 2000 were used to demonstrate that the ForCent model could accurately simulate ecosystem carbon dynamics for the Oak Ridge National Laboratory deciduous forest. A comparison of ForCent versus observed soil pool 14C signature (? 14C) data from the Enriched Background Isotope Study 14C experiment (1999-2006) shows that the model correctly simulates the temporal dynamicsmore » of the 14C label as it moved from the surface litter and roots into the mineral soil organic matter pools. ForCent model validation was performed by comparing the observed Enriched Background Isotope Study experimental data with simulated live and dead root biomass ? 14C data, and with soil respiration ? 14C (mineral soil, humus layer, leaf litter layer, and total soil respiration) data. Results show that the model correctly simulates the impact of the Enriched Background Isotope Study 14C experimental treatments on soil respiration ? 14C values for the different soil organic matter pools. Model results suggest that a two-pool root growth model correctly represents root carbon dynamics and inputs to the soil. The model fitting process and sensitivity analysis exposed uncertainty in our estimates of the fraction of mineral soil in the slow and passive pools, dissolved organic carbon flux out of the litter layer into the mineral soil, and mixing of the humus layer into the mineral soil layer.« less

Surface morphological evolution of epitaxial CrN(001) layers

NASA Astrophysics Data System (ADS)

Frederick, J. R.; Gall, D.

2005-09-01

CrN layers, 57 and 230 nm thick, were grown on MgO(001) at Ts=600-800 °C by ultrahigh-vacuum magnetron sputter deposition in pure N2 discharges from an oblique deposition angle α=80°. Layers grown at 600 °C nucleate as single crystals with a cube-on-cube epitaxial relationship with the substrate. However, rough surfaces with cauliflower-type morphologies cause the nucleation of misoriented CrN grains that develop into cone-shaped grains that protrude out of the epitaxial matrix to form triangular faceted surface mounds. The surface morphology of epitaxial CrN(001) grown at 700 °C is characterized by dendritic ridge patterns extending along the orthogonal <110> directions superposed by square-shaped super mounds with <100> edges. The ridge patterns are attributed to a Bales-Zangwill instability while the supermounds form due to atomic shadowing which leads to the formation of epitaxial inverted pyramids that are separated from the surrounding layer by tilted nanovoids. Growth at 800 °C yields complete single crystals with smooth surfaces. The root-mean-square surface roughness for 230-nm-thick layers decreases from 18.8 to 9.3 to 1.1 nm as Ts is raised from 600 to 700 to 800 °C. This steep decrease is due to a transition in the roughening mechanism from atomic shadowing to kinetic roughening. Atomic shadowing is dominant at 600 and 700 °C, where misoriented grains and supermounds, respectively, capture a larger fraction of the oblique deposition flux in comparison to the surrounding epitaxial matrix, resulting in a high roughening rate that is described by a power law with an exponent β>0.5. In contrast, kinetic roughening controls the surface morphology for Ts=800 °C, as well as the epitaxial fraction of the layers grown at 600 and 700 °C, yielding relatively smooth surfaces and β<=0.27.

Phytochemical investigations and antioxidant potential of roots of Leea macrophylla (Roxb.).

PubMed

Mahmud, Zobaer Al; Bachar, Sitesh C; Hasan, Choudhury Mahmood; Emran, Talha Bin; Qais, Nazmul; Uddin, Mir Muhammad Nasir

2017-07-06

Oleanolic acid (NZ-15), 7 α, 28-olean diol (NZ-38) and Stigmasterol (NZ-14) were isolated from the ethanolic extracts of the roots of Leea macrophylla (Family: Leeaceae) by using chromatographic analysis. This is the first report of isolation of these compounds from this plant. Their structures were constructed by spectroscopic analysis and by comparing the data with the published one. Subsequently the ethanolic extract was fractionated with two organic solvents and all the fractions were studied to evaluate their in vitro antioxidant property. The ethanolic extract was fractionated with two organic solvents and all the fractions were studied to evaluate their in vitro antioxidant property by DPPH free radical scavenging assay, superoxide anion radical scavenging assay, nitric oxide radical scavenging assay, and reducing power assay. In the DPPH free radical scavenging assay and superoxide radical scavenging assay, the ethyl acetate soluble fraction of ethanolic extract revealed the highest free radical scavenging activity with IC 50 value of 2.65 and 155.62 μg/ml, respectively as compared to standard ascorbic acid (IC 50 value of 5.8 and 99.66 μg/ml). Ethyl acetate fraction also possessed highest reducing power activity with an EC50 value of 15.27 μg/ml compared to ascorbic acid (EC 50 0.91 μg/ml). On the other hand, the carbon tetrachloride fraction exhibited most significant NO scavenging activity with IC 50 value of 277.8 μg/ml that was even higher than that of standard ascorbic acid (IC 50 value 356.04 μg/ml). In addition, the total phenolic contents of these extract and fractions were evaluated using Folin-Ciocalteu reagent and varied from 7.93 to 50.21 mg/g dry weight expressed as gallic acid equivalents (GAE). This study showed that different extracts of roots of L. macrophylla possess potential DPPH, superoxide, and NO free radical scavenging activities. The antioxidant activities of the plant extracts might be due to the presence of oleanolic acid, oleanolic acid derivative 7 α, 28-olean diol and stigmasterol.

The effect of MTAD, an endodontic irrigant, on fibroblast attachment to periodontally affected root surfaces: A SEM analysis

PubMed Central

Ghandi, Mostafa; Houshmand, Behzad; Nekoofar, Mohammad H.; Tabor, Rachel K.; Yadeghari, Zahra; Dummer, Paul M. H.

2013-01-01

Background: Root surface debridement (RSD) is necessary to create an environment suitable for reattachment of the periodontium. Root surface conditioning may aid the formation of a biocompatible surface suitable for cell reattachment. BioPure™ MTAD (mixture of Doxycycline, citric acid and a detergent) is an endodontic irrigant with antibacterial properties and the ability to remove smear layer. It was hypothesized that MTAD may be useful for root surface conditioning. The efficacy of MTAD as a conditioner was measured by examining fibroblast attachment to root surfaces. Materials and Methods: Thirty-two specimens of human teeth with advanced periodontal disease were used. The surfaces were root planed until smooth. Half of the specimens were treated with 0.9% saline and the other samples with Biopure MTAD. As a negative control group, five further samples were left unscaled with surface calculus. Human gingival fibroblast cells HGF1-PI1 were cultured and poured over the tooth specimens and incubated. After fixation, the samples were sputter-coated with gold and examined with a SEM. The morphology and number of attached, fixed viable cells were examined. The data was analysed using the Mann-Whitney-U statistical test. Results: There was no significant difference between the numbers of attached cells in the experimental group treated with MTAD and the control group treated with saline. Little or no attached cells were seen in the negative control group. Conclusion: RSD created an environment suitable for cell growth and attachment in a laboratory setting. The use of MTAD did not promote the attachment and growth of cells on the surface of human roots following RSD. PMID:23869124

Identification and effect of two flavonoids from root bark of Morus alba against Ichthyophthirius multifiliis in grass carp

USDA-ARS?s Scientific Manuscript database

Morus alba is an important plant for sericulture and has a high medicinal value. In this study, two flavonoids (kuwanons G and O) with antiparasitic activity were isolated from the root bark of M. alba by bioassay-guided fractionation. The chemical structures were determined by pectroscopic analys...

Sorocenols G and H, Anti-MRSA Oxygen Heterocyclic Diels-Alder-type Adducts from Sorocea muriculata Roots

USDA-ARS?s Scientific Manuscript database

Bioassay-guided fractionation of a root extract of Sorocea muriculata led to the isolation and identification of two new oxygen heterocyclic Diels-Alder-type adducts, sorocenols G (1) and H (2), along with lupeol-3-(3'R-hydroxytetradecanoate) and oxyresveratrol. The structures of 1 and 2 were eluci...

The plasma membrane proteome of Medicago truncatula roots as modified by arbuscular mycorrhizal symbiosis.

PubMed

Aloui, Achref; Recorbet, Ghislaine; Lemaître-Guillier, Christelle; Mounier, Arnaud; Balliau, Thierry; Zivy, Michel; Wipf, Daniel; Dumas-Gaudot, Eliane

2018-01-01

In arbuscular mycorrhizal (AM) roots, the plasma membrane (PM) of the host plant is involved in all developmental stages of the symbiotic interaction, from initial recognition to intracellular accommodation of intra-radical hyphae and arbuscules. Although the role of the PM as the agent for cellular morphogenesis and nutrient exchange is especially accentuated in endosymbiosis, very little is known regarding the PM protein composition of mycorrhizal roots. To obtain a global overview at the proteome level of the host PM proteins as modified by symbiosis, we performed a comparative protein profiling of PM fractions from Medicago truncatula roots either inoculated or not with the AM fungus Rhizophagus irregularis. PM proteins were isolated from root microsomes using an optimized discontinuous sucrose gradient; their subsequent analysis by liquid chromatography followed by mass spectrometry (MS) identified 674 proteins. Cross-species sequence homology searches combined with MS-based quantification clearly confirmed enrichment in PM-associated proteins and depletion of major microsomal contaminants. Changes in protein amounts between the PM proteomes of mycorrhizal and non-mycorrhizal roots were monitored further by spectral counting. This workflow identified a set of 82 mycorrhiza-responsive proteins that provided insights into the plant PM response to mycorrhizal symbiosis. Among them, the association of one third of the mycorrhiza-responsive proteins with detergent-resistant membranes pointed at partitioning to PM microdomains. The PM-associated proteins responsive to mycorrhization also supported host plant control of sugar uptake to limit fungal colonization, and lipid turnover events in the PM fraction of symbiotic roots. Because of the depletion upon symbiosis of proteins mediating the replacement of phospholipids by phosphorus-free lipids in the plasmalemma, we propose a role of phosphate nutrition in the PM composition of mycorrhizal roots.

Implementing Dynamic Root Optimization in Noah-MP for Simulating Phreatophytic Root Water Uptake

NASA Astrophysics Data System (ADS)

Wang, Ping; Niu, Guo-Yue; Fang, Yuan-Hao; Wu, Run-Jian; Yu, Jing-Jie; Yuan, Guo-Fu; Pozdniakov, Sergey P.; Scott, Russell L.

2018-03-01

Widely distributed in arid and semiarid regions, phreatophytic roots extend into the saturated zone and extract water directly from groundwater. In this paper, we implemented a vegetation optimality model of root dynamics (VOM-ROOT) in the Noah land surface model with multiparameterization options (Noah-MP LSM) to model the extraction of groundwater through phreatophytic roots at a riparian site with a hyperarid climate (with precipitation of 35 mm/yr) in northwestern China. VOM-ROOT numerically describes the natural optimization of the root profile in response to changes in subsurface water conditions. The coupled Noah-MP/VOM-ROOT model substantially improves the simulation of surface energy and water fluxes, particularly during the growing season, compared to the prescribed static root profile in the default Noah-MP. In the coupled model, more roots are required to grow into the saturated zone to meet transpiration demand when the groundwater level declines over the growing season. The modeling results indicate that at the study site, the modeled annual transpiration is 472 mm, accounting for 92.3% of the total evapotranspiration. Direct root water uptake from the capillary fringe and groundwater, which is supplied by lateral groundwater flow, accounts for approximately 84% of the total transpiration. This study demonstrates the importance of implementing a dynamic root scheme in a land surface model for adequately simulating phreatophytic root water uptake and the associated latent heat flux.

Changes in root hydraulic conductivity facilitate the overall hydraulic response of rice (Oryza sativa L.) cultivars to salt and osmotic stress.

PubMed

Meng, Delong; Fricke, Wieland

2017-04-01

The aim of the present work was to assess the significance of changes in root AQP gene expression and hydraulic conductivity (Lp) in the regulation of water balance in two hydroponically-grown rice cultivars (Azucena, Bala) which differ in root morphology, stomatal regulation and aquaporin (AQP) isoform expression. Plants were exposed to NaCl (25 mM, 50 mM) and osmotic stress (5%, 10% PEG6000). Root Lp was determined for exuding root systems (osmotic forces driving water uptake; 'exudation Lp') and transpiring plants (hydrostatic forces dominating; 'transpiration-Lp'). Gene expression was analysed by qPCR. Stress treatments caused a consistent and significant decrease in plant growth, transpirational water loss, stomatal conductance, shoot-to-root surface area ratio and root Lp. Comparison of exudation-with transpiration-Lp supported a significant contribution of AQP-facilitated water flow to root water uptake. Changes in root Lp in response to treatments were correlated much stronger with root morphological characteristics, such as the number of main and lateral roots, surface area ratio of root to shoot and plant transpiration rate than with AQP gene expression. Changes in root Lp, involving AQP function, form an integral part of the plant hydraulic response to stress and facilitate changes in the root-to-shoot surface area ratio, transpiration and stomatal conductance. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Bayesian aerosol retrieval algorithm for MODIS AOD retrieval over land

NASA Astrophysics Data System (ADS)

Lipponen, Antti; Mielonen, Tero; Pitkänen, Mikko R. A.; Levy, Robert C.; Sawyer, Virginia R.; Romakkaniemi, Sami; Kolehmainen, Ville; Arola, Antti

2018-03-01

We have developed a Bayesian aerosol retrieval (BAR) algorithm for the retrieval of aerosol optical depth (AOD) over land from the Moderate Resolution Imaging Spectroradiometer (MODIS). In the BAR algorithm, we simultaneously retrieve all dark land pixels in a granule, utilize spatial correlation models for the unknown aerosol parameters, use a statistical prior model for the surface reflectance, and take into account the uncertainties due to fixed aerosol models. The retrieved parameters are total AOD at 0.55 µm, fine-mode fraction (FMF), and surface reflectances at four different wavelengths (0.47, 0.55, 0.64, and 2.1 µm). The accuracy of the new algorithm is evaluated by comparing the AOD retrievals to Aerosol Robotic Network (AERONET) AOD. The results show that the BAR significantly improves the accuracy of AOD retrievals over the operational Dark Target (DT) algorithm. A reduction of about 29 % in the AOD root mean square error and decrease of about 80 % in the median bias of AOD were found globally when the BAR was used instead of the DT algorithm. Furthermore, the fraction of AOD retrievals inside the ±(0.05+15 %) expected error envelope increased from 55 to 76 %. In addition to retrieving the values of AOD, FMF, and surface reflectance, the BAR also gives pixel-level posterior uncertainty estimates for the retrieved parameters. The BAR algorithm always results in physical, non-negative AOD values, and the average computation time for a single granule was less than a minute on a modern personal computer.

The Regulation of Growth in the Distal Elongation Zone of Maize Roots

NASA Technical Reports Server (NTRS)

Evans, Michael L.

1998-01-01

The major goals of the proposed research were 1. To develop specialized software for automated whole surface root expansion analysis and to develop technology for controlled placement of surface electrodes for analysis of relationships between root growth and root pH and electrophysiological properties. 2. To measure surface pH patterns and determine the possible role of proton flux in gravitropic sensing or response, and 3. To determine the role of auxin transport in establishment of patterns of proton flux and electrical gradients during the gravitropic response of roots with special emphasis on the role of the distal elongation zone in the early phases of the gravitropic response.

Variability of Root Traits in Spring Wheat Germplasm

PubMed Central

Narayanan, Sruthi; Mohan, Amita; Gill, Kulvinder S.; Prasad, P. V. Vara

2014-01-01

Root traits influence the amount of water and nutrient absorption, and are important for maintaining crop yield under drought conditions. The objectives of this research were to characterize variability of root traits among spring wheat genotypes and determine whether root traits are related to shoot traits (plant height, tiller number per plant, shoot dry weight, and coleoptile length), regions of origin, and market classes. Plants were grown in 150-cm columns for 61 days in a greenhouse under optimal growth conditions. Rooting depth, root dry weight, root: shoot ratio, and shoot traits were determined for 297 genotypes of the germplasm, Cultivated Wheat Collection (CWC). The remaining root traits such as total root length and surface area were measured for a subset of 30 genotypes selected based on rooting depth. Significant genetic variability was observed for root traits among spring wheat genotypes in CWC germplasm or its subset. Genotypes Sonora and Currawa were ranked high, and genotype Vandal was ranked low for most root traits. A positive relationship (R2≥0.35) was found between root and shoot dry weights within the CWC germplasm and between total root surface area and tiller number; total root surface area and shoot dry weight; and total root length and coleoptile length within the subset. No correlations were found between plant height and most root traits within the CWC germplasm or its subset. Region of origin had significant impact on rooting depth in the CWC germplasm. Wheat genotypes collected from Australia, Mediterranean, and west Asia had greater rooting depth than those from south Asia, Latin America, Mexico, and Canada. Soft wheat had greater rooting depth than hard wheat in the CWC germplasm. The genetic variability identified in this research for root traits can be exploited to improve drought tolerance and/or resource capture in wheat. PMID:24945438

Hepatoprotective activity of Trichilia roka on carbon tetrachloride-induced liver damage in rats.

PubMed

Germanò, M P; D'Angelo, V; Sanogo, R; Morabito, A; Pergolizzi, S; De Pasquale, R

2001-11-01

Trichilia roka Chiov. (Meliaceae) is a tree widely distributed in tropical Africa. It has been used in Mali folk medicine for the treatment of various illnesses. A decoction of the roots is taken as a remedy for colds and pneumonia, and it is used as a diuretic and in hepatic disorders. We have evaluated the hepatoprotective effects of a decoction of Trichilia roka root on CCl4-induced acute liver damage in rats. Treatment with the decoction showed a significant protective action made evident by its effect on the levels of glutamate oxalacetate transaminase and glutamate pyruvate transaminase in the serum, on the protein content and lipid peroxidation levels in the liver homogenate. Histopathological changes produced by CCl4, such as necrosis, fatty change, ballooning degeneration and inflammatory infiltration of lymphocytes around the central veins, were clearly recovered by the treatment with Trichilia root decoction. On fractionating this extract into diethyl ether-soluble and water-soluble fractions, the activity was retained in the diethyl ether-soluble fraction. Moreover, the administration of decoction prevented a preferential deposition of collagen around the sinusoidal cell layer, which is responsible for the perisinusoidal fibrosis in the early stage of CCl4 damage. This study showed that treatment with Trichilia roka extracts or silymarin (as reference) appeared to enhance the recovery from CCl4-induced hepatotoxicity. The hepatoprotective properties of Trichilia roka may be correlated to polyphenol content of the decoction and its diethyl ether-soluble fraction.

Temperature changes accompanying near infrared diode laser endodontic treatment of wet canals.

PubMed

Hmud, Raghad; Kahler, William A; Walsh, Laurence J

2010-05-01

Diode laser endodontic treatments such as disinfection or the generation of cavitations should not cause deleterious thermal changes in radicular dentin. This study assessed thermal changes in the root canal and on the root surface when using 940 and 980 nm lasers at settings of 4 W/10 Hz and 2.5 W/25 Hz, respectively, delivered into 2000-mum fibers to generate cavitations in water. The root surface temperature in the apical third was recorded, as was the water temperature in coronal, middle, and apical third regions, by using thermocouples placed inside the canal. Lasing was undertaken with either rest periods or rinsing between 5-second laser exposures. Both diode lasers induced only modest temperature changes on the external root surface at the settings used. Even though the temperature of the water within the canal increased during lasing by as much as 30 degrees C, the external root surface temperature increased by only a maximum of 4 degrees C. Irrigation between laser exposures was highly effective in minimizing thermal changes within the root canal and on the root surface. Diode laser parameters that induce cavitation do not result in adverse thermal changes in radicular dentin. Copyright (c) 2010 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Extracting Metrics for Three-dimensional Root Systems: Volume and Surface Analysis from In-soil X-ray Computed Tomography Data.

PubMed

Suresh, Niraj; Stephens, Sean A; Adams, Lexor; Beck, Anthon N; McKinney, Adriana L; Varga, Tamas

2016-04-26

Plant roots play a critical role in plant-soil-microbe interactions that occur in the rhizosphere, as well as processes with important implications to climate change and crop management. Quantitative size information on roots in their native environment is invaluable for studying root growth and environmental processes involving plants. X-ray computed tomography (XCT) has been demonstrated to be an effective tool for in situ root scanning and analysis. We aimed to develop a costless and efficient tool that approximates the surface and volume of the root regardless of its shape from three-dimensional (3D) tomography data. The root structure of a Prairie dropseed (Sporobolus heterolepis) specimen was imaged using XCT. The root was reconstructed, and the primary root structure was extracted from the data using a combination of licensed and open-source software. An isosurface polygonal mesh was then created for ease of analysis. We have developed the standalone application imeshJ, generated in MATLAB(1), to calculate root volume and surface area from the mesh. The outputs of imeshJ are surface area (in mm(2)) and the volume (in mm(3)). The process, utilizing a unique combination of tools from imaging to quantitative root analysis, is described. A combination of XCT and open-source software proved to be a powerful combination to noninvasively image plant root samples, segment root data, and extract quantitative information from the 3D data. This methodology of processing 3D data should be applicable to other material/sample systems where there is connectivity between components of similar X-ray attenuation and difficulties arise with segmentation.

Phototropism of Arabidopsis thaliana in microgravity and fractional gravity on the International Space Station.

PubMed

Kiss, John Z; Millar, Katherine D L; Edelmann, Richard E

2012-08-01

While there is a great deal of knowledge regarding plant growth and development in microgravity aboard orbiting spacecraft, there is little information available about these parameters in reduced or fractional gravity conditions (less than the nominal 1g on Earth). Thus, in these experiments using the European Modular Cultivation System on the International Space Station, we studied the interaction between phototropism and gravitropism in the WT and mutants of phytochrome A and B of Arabidopis thaliana. Fractional gravity and the 1 g control were provided by centrifuges in the spaceflight hardware, and unidirectional red and blue illumination followed a white light growth period in the time line of the space experiments. The existence of red-light-based positive phototropism in hypocotyls of seedlings that is mediated by phytochrome was confirmed in these microgravity experiments. Fractional gravity studies showed an attenuation of red-light-based phototropism in both roots and hypocotyls of seedlings occurring due to gravitational accelerations ranging from 0.l to 0.3 g. In contrast, blue-light negative phototropism in roots, which was enhanced in microgravity compared with the 1g control, showed a significant attenuation at 0.3 g. In addition, our studies suggest that the well-known red-light enhancement of blue-light-induced phototropism in hypocotyls is likely due to an indirect effect by the attenuation of gravitropism. However, red-light enhancement of root blue-light-based phototropism may occur via a more direct effect on the phototropism system itself, most likely through the phytochrome photoreceptors. To our knowledge, these experiments represent the first to examine the behavior of flowering plants in fractional or reduced gravity conditions.

Neural Network-Based Retrieval of Surface and Root Zone Soil Moisture using Multi-Frequency Remotely-Sensed Observations

NASA Astrophysics Data System (ADS)

Hamed Alemohammad, Seyed; Kolassa, Jana; Prigent, Catherine; Aires, Filipe; Gentine, Pierre

2017-04-01

Knowledge of root zone soil moisture is essential in studying plant's response to different stress conditions since plant photosynthetic activity and transpiration rate are constrained by the water available through their roots. Current global root zone soil moisture estimates are based on either outputs from physical models constrained by observations, or assimilation of remotely-sensed microwave-based surface soil moisture estimates with physical model outputs. However, quality of these estimates are limited by the accuracy of the model representations of physical processes (such as radiative transfer, infiltration, percolation, and evapotranspiration) as well as errors in the estimates of the surface parameters. Additionally, statistical approaches provide an alternative efficient platform to develop root zone soil moisture retrieval algorithms from remotely-sensed observations. In this study, we present a new neural network based retrieval algorithm to estimate surface and root zone soil moisture from passive microwave observations of SMAP satellite (L-band) and AMSR2 instrument (X-band). SMAP early morning observations are ideal for surface soil moisture retrieval. AMSR2 mid-night observations are used here as an indicator of plant hydraulic properties that are related to root zone soil moisture. The combined observations from SMAP and AMSR2 together with other ancillary observations including the Solar-Induced Fluorescence (SIF) estimates from GOME-2 instrument provide necessary information to estimate surface and root zone soil moisture. The algorithm is applied to observations from the first 18 months of SMAP mission and retrievals are validated against in-situ observations and other global datasets.

Pythagorean Approximations and Continued Fractions

ERIC Educational Resources Information Center

Peralta, Javier

2008-01-01

In this article, we will show that the Pythagorean approximations of [the square root of] 2 coincide with those achieved in the 16th century by means of continued fractions. Assuming this fact and the known relation that connects the Fibonacci sequence with the golden section, we shall establish a procedure to obtain sequences of rational numbers…

SMAP Level 4 Surface and Root Zone Soil Moisture

NASA Technical Reports Server (NTRS)

Reichle, R.; De Lannoy, G.; Liu, Q.; Ardizzone, J.; Kimball, J.; Koster, R.

2017-01-01

The SMAP Level 4 soil moisture (L4_SM) product provides global estimates of surface and root zone soil moisture, along with other land surface variables and their error estimates. These estimates are obtained through assimilation of SMAP brightness temperature observations into the Goddard Earth Observing System (GEOS-5) land surface model. The L4_SM product is provided at 9 km spatial and 3-hourly temporal resolution and with about 2.5 day latency. The soil moisture and temperature estimates in the L4_SM product are validated against in situ observations. The L4_SM product meets the required target uncertainty of 0.04 m(exp. 3)m(exp. -3), measured in terms of unbiased root-mean-square-error, for both surface and root zone soil moisture.

Intracanal bisphosphonate does not inhibit replacement resorption associated with delayed replantation of monkey incisors.

PubMed

Thong, Yo Len; Messer, Harold H; Zain, Rosnah Binti; Saw, Lip Hean; Yoong, Lai Thong

2009-08-01

Progressive replacement resorption following delayed replantation of avulsed teeth has proved to be an intractable clinical problem. A wide variety of therapeutic approaches have failed to result in the predictable arrest of resorption, with a good long-term prognosis for tooth survival. Bisphosphonates are used in the medical management of a range of bone disorders and topically applied bisphosphonate has been reported to inhibit root resorption in dogs. This study evaluated the effectiveness of a bisphosphonate (etidronate disodium) as an intracanal medicament in the root canals of avulsed monkey teeth, placed before replantation after 1 h of extraoral dry storage. Incisors of six Macaca fascicularis monkeys were extracted and stored dry for 1 h. Teeth were then replanted after canal contamination with dental plaque (negative control) or after root canal debridement and placement of etidronate sealed in the canal space. A positive control of calcium hydroxide placed 8-9 days after replantation was also included. All monkeys were sacrificed 8 weeks later and block sections were prepared for histomorphometric assessment of root resorption and periodontal ligament status. Untreated teeth showed the greatest extent of root resorption (46% of the root surface), which was predominantly inflammatory in nature. Calcium hydroxide treated teeth showed the lowest overall level of resorption (<30% of the root surface), while the bisphosphonate-treated group was intermediate (39%). Ankylosis, defined as the extent of the root surface demonstrating direct bony union to both intact and resorbed root surface, was the lowest in the untreated control group (15% of the root surface), intermediate in the calcium hydroxide group (27%) and the highest in the bisphosphonate group (41%). Bony attachment to the tooth root was divided approximately equally between attachment to intact cementum and to previously resorbed dentin. Overall, bisphosphonate resulted in a worse outcome than calcium hydroxide in terms of both root resorption and ankylosis.

A comparison of root surface temperatures using different obturation heat sources.

PubMed

Lee, F S; Van Cura, J E; BeGole, E

1998-09-01

This study compared root surface temperatures produced during warm vertical obturation using the System B Heat Source (SB), the Touch 'n Heat device (TH), and a flame-heated carrier (FH). The root canals of 30 maxillary incisor, premolar, and mandibular incisor teeth were prepared; divided into three groups; and obturated using each heat source. A thermocouple placed 2 mm below the cementoenamel junction transferred the temperature rise on the external root surface to a digital thermometer. SB surface temperature rise was < 10 degrees C for all experimental teeth. TH temperature rise in maxillary incisors and premolars was < 10 degrees C; however, > 10 degrees C was observed for mandibular incisors. FH produced a > 10 degrees C surface temperature rise in all experimental teeth. The critical level of root surface heat required to produce irreversible bone damage is believed to be > 10 degrees C. The findings of this study suggest that warm vertical condensation with the SB should not damage supporting periradicular tissues. However, caution should be used with TH and FH on mandibular incisors.

Quantifying root water extraction after drought recovery using sub-mm in situ empirical data

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

Dhiman, Indu; Bilheux, Hassina Z.; DeCarlo, Keito F.

Root-specific responses to stress are not well-known, and have been largely based on indirect measurements of bulk soil water extraction, which limits mechanistic modeling of root function. Here, we used neutron radiography to examine in situ root-soil water dynamics of a previously droughted black cottonwood ( Populus trichocarpa) seedling, contrasting water uptake by younger, thinner or older, thicker parts of the fine root system. The smaller diameter roots had greater water uptake capacity per unit surface area than the larger diameter roots, but they had less total surface area leading to less total water extraction; rates ranged from 0.0027 –more » 0.0116 g cm -2 hr -1. The finest most-active roots were not visible in the radiographs, indicating the need to include destructive sampling. Analysis based on bulk soil hydraulic properties indicated substantial redistribution of water via saturated/unsaturated flow, capillary wicking, and root hydraulic redistribution across the layers - suggesting water uptake dynamics following an infiltration event may be more complex than approximated by common soil hydraulic or root surface area modeling approaches. Lastly, our results highlight the need for continued exploration of root-trait specific water uptake rates in situ, and impacts of roots on soil hydraulic properties – both critical components for mechanistic modeling of root function.« less

Quantifying root water extraction after drought recovery using sub-mm in situ empirical data

DOE PAGES

Dhiman, Indu; Bilheux, Hassina Z.; DeCarlo, Keito F.; ...

2017-09-09

Root-specific responses to stress are not well-known, and have been largely based on indirect measurements of bulk soil water extraction, which limits mechanistic modeling of root function. Here, we used neutron radiography to examine in situ root-soil water dynamics of a previously droughted black cottonwood ( Populus trichocarpa) seedling, contrasting water uptake by younger, thinner or older, thicker parts of the fine root system. The smaller diameter roots had greater water uptake capacity per unit surface area than the larger diameter roots, but they had less total surface area leading to less total water extraction; rates ranged from 0.0027 –more » 0.0116 g cm -2 hr -1. The finest most-active roots were not visible in the radiographs, indicating the need to include destructive sampling. Analysis based on bulk soil hydraulic properties indicated substantial redistribution of water via saturated/unsaturated flow, capillary wicking, and root hydraulic redistribution across the layers - suggesting water uptake dynamics following an infiltration event may be more complex than approximated by common soil hydraulic or root surface area modeling approaches. Lastly, our results highlight the need for continued exploration of root-trait specific water uptake rates in situ, and impacts of roots on soil hydraulic properties – both critical components for mechanistic modeling of root function.« less

Root architecture and wind-firmness of mature Pinus pinaster.

PubMed

Danjon, Frédéric; Fourcaud, Thierry; Bert, Didier

2005-11-01

This study aims to link three-dimensional coarse root architecture to tree stability in mature timber trees with an average of 1-m rooting depth. Undamaged and uprooted trees were sampled in a stand damaged by a storm. Root architecture was measured by three-dimensional (3-D) digitizing. The distribution of root volume by root type and in wind-oriented sectors was analysed. Mature Pinus pinaster root systems were organized in a rigid 'cage' composed of a taproot, the zone of rapid taper of horizontal surface roots and numerous sinkers and deep roots, imprisoning a large mass of soil and guyed by long horizontal surface roots. Key compartments for stability exhibited strong selective leeward or windward reinforcement. Uprooted trees showed a lower cage volume, a larger proportion of oblique and intermediate depth horizontal roots and less wind-oriented root reinforcement. Pinus pinaster stability on moderately deep soils is optimized through a typical rooting pattern and a considerable structural adaptation to the prevailing wind and soil profile.

Potential for temperature change during application of ultrasonic vibration to intra-radicular posts.

PubMed

Satterthwaite, Julian D; Stokes, Alastair N; Frankel, Nicholas T N

2003-06-01

The aim of this study was to assess the potential for heat production when intra-radicular posts were subjected to ultrasonic vibration. Thirty zirconium ceramic posts and thirty stainless steel posts were luted into canine roots. Ultrasonic vibration was applied to the top of each post for thirty minutes and temperature change on the root surface was measured. The mean peak temperature rise from baseline was 18.7 degrees C. Post type had no influence on peak temperature. Temperature increase on the external root surfaces increased as the thickness of dentine between post and root surface reduced.

Effect of the association between citric acid and EDTA on root surface etching.

PubMed

Manzolli Leite, Fabio Renato; Nascimento, Gustavo Giacomelli; Manzolli Leite, Elza Regina; Leite, Amauri Antiquera; Cezar Sampaio, Josá Eduardo

2013-09-01

This study aims to compare the clot stabilization on root surfaces conditioned with citric acid and ethylenediamine-tetraacetic acid (EDTA). Scaled root samples (n = 100) were set in fve groups: group I-control group (saline solution); group II (24% EDTA); group III (25% citric acid); group IV (EDTA + citric acid); group V (citric acid + EDTA). Fifty samples were assessed using the root surface modifcation index (RSMI). The other 50 received a blood drop after conditioning. Clot formation was assessed using blood elements adhesion index (BEAI). A blind examiner evaluated photomicrographs. Statistical analysis considered p < 0.05. Groups-III and G-V attained the best results for RSMI and BEAI in comparison to control. The worst results for clot stabilization were seen in group-II. EDTA employment before citric acid (group-IV) reduced clot formation in comparison to citric acid use alone (group-III). Root conditioning with citric acid alone and before EDTA had the best results for smear layer removal and clot stabilization. EDTA inhibited clot stabilization on root surface and must have a residual activity once it has diminished clot adhesion to root even after citric acid conditioning. Thus, EDTA can be used to neutralize citric acid effects on periodontal cells without affecting clot stabilization. Clinical signifcance: To demonstrate that citric acid use on root surfaces previously affected by periodontal disease may favor clot stabilization and may have a benefcial effect on surgical outcomes. Also, EDTA can be used to neutralize citric acid effects on periodontal cells.

Fine root mercury heterogeneity: metabolism of lower-order roots as an effective route for mercury removal.

PubMed

Wang, Jun-Jian; Guo, Ying-Ying; Guo, Da-Li; Yin, Sen-Lu; Kong, De-Liang; Liu, Yang-Sheng; Zeng, Hui

2012-01-17

Fine roots are critical components for plant mercury (Hg) uptake and removal, but the patterns of Hg distribution and turnover within the heterogeneous fine root components and their potential limiting factors are poorly understood. Based on root branching structure, we studied the total Hg (THg) and its cellular partitioning in fine roots in 6 Chinese subtropical trees species and the impacts of root morphological and stoichiometric traits on Hg partitioning. The THg concentration generally decreased with increasing root order, and was higher in cortex than in stele. This concentration significantly correlated with root length, diameter, specific root length, specific root area, and nitrogen concentration, whereas its cytosolic fraction (accounting for <10% of THg) correlated with root carbon and sulfur concentrations. The estimated Hg return flux from dead fine roots outweighed that from leaf litter, and ephemeral first-order roots that constituted 7.2-22.3% of total fine root biomass may have contributed most to this flux (39-71%, depending on tree species and environmental substrate). Our results highlight the high capacity of Hg stabilization and Hg return by lower-order roots and demonstrate that turnover of lower-order roots may be an effective strategy of detoxification in perennial tree species.

Changes in δ(13)C of dark respired CO2 and organic matter of different organs during early ontogeny in peanut plants.

PubMed

Ghashghaie, Jaleh; Badeck, Franz W; Girardin, Cyril; Sketriené, Diana; Lamothe-Sibold, Marlène; Werner, Roland A

2015-01-01

Carbon isotope composition in respired CO2 and organic matter of individual organs were measured on peanut seedlings during early ontogeny in order to compare fractionation during heterotrophic growth and transition to autotrophy in a species with lipid seed reserves with earlier results obtained on beans. Despite a high lipid content in peanut seeds (48%) compared with bean seeds (1.5%), the isotope composition of leaf- and root-respired CO2 as well as its changes during ontogeny were similar to already published data on bean seedlings: leaf-respired CO2 became (13)C-enriched reaching -21.5‰, while root-respired CO2 became (13)C-depleted reaching around -31‰ at the four-leaf stage. The opposite respiratory fractionation in leaves vs. roots already reported for C3 herbs was thus confirmed for peanuts. However, contrarily to beans, the peanut cotyledon-respired CO2 was markedly (13)C-enriched, and its (13)C-depletion was noted from the two-leaf stage onwards only. Carbohydrate amounts being very low in peanut seeds, this cannot be attributed solely to their use as respiratory substrate. The potential role of isotope fractionation during glyoxylate cycle and/or gluconeogenesis on the (13)C-enriched cotyledon-respired CO2 is discussed.

[Effects of tree species diversity on fine-root biomass and morphological characteristics in subtropical Castanopsis carlesii forests].

PubMed

Wang, Wei-Wei; Huang, Jin-Xue; Chen, Feng; Xiong, De-Cheng; Lu, Zheng-Li; Huang, Chao-Chao; Yang, Zhi-Jie; Chen, Guang-Shui

2014-02-01

Fine roots in the Castanopsis carlesii plantation forest (MZ), the secondary forest of C. carlesii through natural regeneration with anthropogenic promotion (AR), and the secondary forest of C. carlesii through natural regeneration (NR) in Sanming City, Fujian Province, were estimated by soil core method to determine the influence of tree species diversity on biomass, vertical distribution and morphological characteristics of fine roots. The results showed that fine root biomass for the 0-80 cm soil layer in the MZ, AR and NR were (182.46 +/- 10.81), (242.73 +/- 17.85) and (353.11 +/- 16.46) g x m(-2), respectively, showing an increased tendency with increasing tree species diversity. In the three forests, fine root biomass was significantly influenced by soil depth, and fine roots at the 0-10 cm soil layer accounted for more than 35% of the total fine root biomass. However, the interaction of stand type and soil depth on fine-root distribution was not significant, indicating no influence of tree species diversity on spatial niche segregation in fine roots. Root surface area density and root length density were the highest in NR and lowest in the MZ. Specific root length was in the order of AR > MZ > NR, while specific root surface area was in the order of NR > MZ > AR. There was no significant interaction of stand type and soil depth on specific root length and specific root surface area. Fine root morphological plasticity at the stand level had no significant response to tree species diversity.

A simple hydrologically based model of land surface water and energy fluxes for general circulation models

NASA Technical Reports Server (NTRS)

Liang, XU; Lettenmaier, Dennis P.; Wood, Eric F.; Burges, Stephen J.

1994-01-01

A generalization of the single soil layer variable infiltration capacity (VIC) land surface hydrological model previously implemented in the Geophysical Fluid Dynamics Laboratory (GFDL) general circulation model (GCM) is described. The new model is comprised of a two-layer characterization of the soil column, and uses an aerodynamic representation of the latent and sensible heat fluxes at the land surface. The infiltration algorithm for the upper layer is essentially the same as for the single layer VIC model, while the lower layer drainage formulation is of the form previously implemented in the Max-Planck-Institut GCM. The model partitions the area of interest (e.g., grid cell) into multiple land surface cover types; for each land cover type the fraction of roots in the upper and lower zone is specified. Evapotranspiration consists of three components: canopy evaporation, evaporation from bare soils, and transpiration, which is represented using a canopy and architectural resistance formulation. Once the latent heat flux has been computed, the surface energy balance is iterated to solve for the land surface temperature at each time step. The model was tested using long-term hydrologic and climatological data for Kings Creek, Kansas to estimate and validate the hydrological parameters, and surface flux data from three First International Satellite Land Surface Climatology Project Field Experiment (FIFE) intensive field campaigns in the summer-fall of 1987 to validate the surface energy fluxes.

The inhibiting effects of components of stinging nettle roots on experimentally induced prostatic hyperplasia in mice.

PubMed

Lichius, J J; Renneberg, H; Blaschek, W; Aumüller, G; Muth, C

1999-10-01

Direct implanting of fetal urogenital sinus (UGS) tissue into the ventral prostate gland of adult mice led to a 4-fold weight increase of the manipulated prostatic lobe. The induced growth could be reduced by the polysaccharide fraction (POLY-M) of the 20% methanolic extract of stinging nettle roots by 33.8%.

Waving and skewing: how gravity and the surface of growth media affect root development in Arabidopsis.

PubMed

Oliva, Michele; Dunand, Christophe

2007-01-01

Arabidopsis seedlings growing on inclined agar surfaces exhibit characteristic root behaviours called 'waving' and 'skewing': the former consists of a series of undulations, whereas the latter is a deviation from the direction of gravity. Even though the precise basis of these growth patterns is not well understood, both gravity and the contact between the medium and the root are considered to be the major players that result in these processes. The influence of these forces on root surface-dependent behaviours can be verified by growing seedlings at different gel pitches: plants growing on vertical plates present roots with slight waving and skewing when compared with seedlings grown on plates held at minor angles of < 90 degrees . However, other factors are thought to modulate root growth on agar; for instance, it has been demonstrated that the presence and concentration of certain compounds in the medium (such as sucrose) and of drugs able to modify the plant cell cytoskeleton also affect skewing and waving. The recent discovery of an active role of ethylene on surface-dependent root behaviour, and the finding of new mutants showing anomalous growth, pave the way for a more detailed description of these phenomena.

Antimicrobial activity of Carpolobia lutea extracts and fractions.

PubMed

Nwidu, Lucky L; Nwafor, Paul A; Vilegas, Wagner

2012-01-01

Carpolobia lutea (G. Don) (Polygalaceae) is a tropical medicinal plant putative in traditional medicines against gonorrhea, gingivitis, infertility, antiulcer and malaria. The present study evaluated the antimicrobial, antifungal and antihelicobacter effects of extracts C. lutea leaf, stem and root. The extracts were examined using the disc-diffusion and Microplates of 96 wells containing Muller-Hinton methods against some bacterial strains: Eschericia coli (ATCC 25922), E. coli (ATCC10418), Pseudomonas aeruginosa (ATCC 27853), Staphylococcus aureus (ATCC 25923), Staphyllococus aureus (ATCC 6571), Enterococcus faecalis (ATCC 29212) and Bacillus subtilis (NCTC 8853) and four clinical isolates: one fungi (Candida albican) and three bacteria (Salmonella, Sheigella and staphylococcus aureus). The Gram-positive bacteria: Staphylococcus aureus (ATCC 25923), Enterococcus faecalis (ATCC 29212), Bacillus subtilis (ATCC 19659) and the Gram-negative bacteria: Escherichia coli (ATCC 25922), Pseudomonas aeruginosa (ATCC 27853), Cândida albicans (ATCC 18804) and Helicobacter pylori (ATCC 43504). Some of these extracts were found to be active against some tested strains but activity against H. pylori was >1000mg/ml and good fungistatic activity against C. albican. The MIC against C. albican is in the order n-HF > CHF > ETF= EAF.The order of potency of fraction was the ethanol root > n-HF leaf > ethanol fraction stem > chloroform fraction leaf = ethyl acetate fraction leaf. Polyphenols were demonstrated in ethanol fraction, ethyl acetate fraction, crude ethyl acetate extract and ethanol extract, respectively. These polyphenols isolated may partly explain and support the use of C. lutea for the treatment of infectious diseases in traditional Ibibio medicine of Nigeria.

Land surface sensitivity of monsoon depressions formed over Bay of Bengal using improved high-resolution land state

NASA Astrophysics Data System (ADS)

Rajesh, P. V.; Pattnaik, S.; Mohanty, U. C.; Rai, D.; Baisya, H.; Pandey, P. C.

2017-12-01

Monsoon depressions (MDs) constitute a large fraction of the total rainfall during the Indian summer monsoon season. In this study, the impact of high-resolution land state is addressed by assessing the evolution of inland moving depressions formed over the Bay of Bengal using a mesoscale modeling system. Improved land state is generated using High Resolution Land Data Assimilation System employing Noah-MP land-surface model. Verification of soil moisture using Soil Moisture and Ocean Salinity (SMOS) and soil temperature using tower observations demonstrate promising results. Incorporating high-resolution land state yielded least root mean squared errors with higher correlation coefficient in the surface and mid tropospheric parameters. Rainfall forecasts reveal that simulations are spatially and quantitatively in accordance with observations and provide better skill scores. The improved land surface characteristics have brought about the realistic evolution of surface, mid-tropospheric parameters, vorticity and moist static energy that facilitates the accurate MDs dynamics in the model. Composite moisture budget analysis reveals that the surface evaporation is negligible compared to moisture flux convergence of water vapor, which supplies moisture into the MDs over land. The temporal relationship between rainfall and moisture convergence show high correlation, suggesting a realistic representation of land state help restructure the moisture inflow into the system through rainfall-moisture convergence feedback.

Adsorption of Eu(III) onto roots of water hyacinth

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

Kelley, C.; Mielke, R.E.; Dimaquibo, D.

1999-05-01

The water hyacinth (Eichhornia crassipes) has drawn attention as a plant capable of removing pollutants, including toxic metals, from water. The authors are interested in the capacity of the water hyacinth to remediate aquatic environments that have been contaminated with the lanthanide metal, europium Eu(III). Using scanning electron microscopy (SEM) they have been able to determine that Eu(III) is adsorbed onto the surface of the roots from water and that the highest concentration of Eu(III) is on the root hairs. X-ray absorption spectroscopy (XAS) techniques were used to speciate the Eu(III) adsorbed onto the surface of the roots. The XASmore » data for Eu-contaminated water hyacinth roots provides evidence of a Eu-oxygen environment and establishes that Eu(III) is coordinated to 10--11 oxygen atoms at a distance of 2.44 {angstrom}. This likely involves binding of Eu(III) to the root via carboxylate groups and hydration of Eu(III) at the root surface.« less

The attachment of V79 and human periodontal ligament fibroblasts on periodontally involved root surfaces following treatment with EDTA, citric acid, or tetracycline HCL: an SEM in vitro study.

PubMed

Chandra, R Viswa; Jagetia, Ganesh Chandra; Bhat, K Mahalinga

2006-02-15

The present in vitro study has been designed to establish and compare the effects of citric acid, EDTA, and tetracycline HCl on human periodontally diseased roots on the structure, attachment, and orientation of V79 (primary Chinese hamster lung fibroblasts) cells and human periodontal ligament fibroblasts (HPDL). Commercially available V79 cells and HPDL derived from healthy human third molars were used in this study. These fibroblasts were left in solution for seven days in order to attain confluence. Forty single-rooted teeth were obtained from patients diagnosed with periodontitis. The crown part was removed under constant irrigation and the root was split vertically into two equal halves, thus, yielding 80 specimens. Following scaling and root planing, the specimens were washed with phosphate buffered saline (PBS) and kept in 50 microg/ml gentamycin sulphate solution for 24 hours. The root pieces were then treated as follows: citric acid at pH 1, 24% EDTA, or with a 10% solution of tetracycline HCl and were then placed in V79 fibroblast cultures and HPDL cultures. The specimens were harvested after four weeks and were fixed in 2.5% glutaraldehyde in PBS before preparation for scanning electron microscopy (SEM). The behavior of V79 cells was similar to that of human periodontal ligament cells on root conditioned surfaces. V79 and HPDL showed a healthy morphology on root surfaces treated with citric acid and EDTA and a relatively unhealthy appearance on root surfaces treated with tetracycline HCl and distilled water (control group). The results suggest the use of citric acid and EDTA as root conditioning agents favorably affects the migration, attachment, and morphology of fibroblasts on human root surfaces, which may play a significant role in periodontal healing and regeneration.

Experimental and theoretical investigations on the antioxidant activity of isoorientin from Crotalaria globosa

NASA Astrophysics Data System (ADS)

Deepha, V.; Praveena, R.; Sivakumar, Raman; Sadasivam, K.

2014-03-01

The increasing interests in naturally occurring flavonoids are well known for their bioactivity as antioxidants. The present investigations with combined experimental and theoretical methods are employed to determine the radical scavenging activity and phytochemicals present in Crotalaria globosa, a novel plant source. Preliminary quantification of ethanolic extract of leaves shows high phenolic and flavonoid content than root extract; also it is validated through DPPHrad assay. Further analysis is carried out with successive extracts of leaves of varying polarity of solvents. In DPPHrad and FRAP assays, ethyl acetate fraction (EtOAc) exhibit higher scavenging activity followed by ethanol fraction (EtOH) whereas in NOS assay ethanol fraction is slightly predominant over the EtOAc fraction. The LC-MS analysis provides tentative information about the presence of flavonoid C-glycoside in EtOAc fraction (yellow solid). Presence of flavonoid isorientin has been confirmed through isolation (PTLC) and detected by spectroscopy methods (UV-visible and 1H NMR). Utilizing B3LYP/6-311G (d,p) level of theory the structure and reactivity of flavonoid isoorientin theoretically have been explored. The analysis of the theoretical Bond dissociation energy values, for all Osbnd H sites of isoorientin reveals that minimum energy is required to dissociate H-atom from B-ring than A and C-rings. In order to validate the antioxidant characteristics of isoorientin the relevant molecular descriptors IP, HOMO-LUMO, Mulliken spin density analysis and molecular electrostatic potential surfaces have been computed and interpreted. From experimental and theoretical results, it is proved that isoorientin can act as potent antiradical scavenger in oxidative system.

Changes in Metabolically Active Bacterial Community during Rumen Development, and Their Alteration by Rhubarb Root Powder Revealed by 16S rRNA Amplicon Sequencing.

PubMed

Wang, Zuo; Elekwachi, Chijioke; Jiao, Jinzhen; Wang, Min; Tang, Shaoxun; Zhou, Chuanshe; Tan, Zhiliang; Forster, Robert J

2017-01-01

The objective of this present study was to explore the initial establishment of metabolically active bacteria and subsequent evolution in four fractions: rumen solid-phase (RS), liquid-phase (RL), protozoa-associated (RP), and epithelium-associated (RE) through early weaning and supplementing rhubarb root powder in 7 different age groups (1, 10, 20, 38, 41, 50, and 60 d) during rumen development. Results of the 16S rRNA sequencing based on RNA isolated from the four fractions revealed that the potentially active bacterial microbiota in four fractions were dominated by the phyla Proteobacteria, Firmicutes , and Bacteroidetes regardless of different ages. An age-dependent increment of Chao 1 richness was observed in the fractions of RL and RE. The principal coordinate analysis (PCoA) indicated that samples in four fractions all clustered based on different age groups, and the structure of the bacterial community in RE was distinct from those in other three fractions. The abundances of Proteobacteria decreased significantly ( P < 0.05) with age, while increases in the abundances of Firmicutes and Bacteroidetes were noted. At the genus level, the abundance of the predominant genus Mannheimia in the Proteobacteria phylum decreased significantly ( P < 0.05) after 1 d, while the genera Quinella, Prevotella, Fretibacterium, Ruminococcus, Lachnospiraceae NK3A20 group , and Atopobium underwent different manners of increases and dominated the bacterial microbiota across four fractions. Variations of the distributions of some specific bacterial genera across fractions were observed, and supplementation of rhubarb affected the relative abundance of various genera of bacteria.

Changes in Metabolically Active Bacterial Community during Rumen Development, and Their Alteration by Rhubarb Root Powder Revealed by 16S rRNA Amplicon Sequencing

PubMed Central

Wang, Zuo; Elekwachi, Chijioke; Jiao, Jinzhen; Wang, Min; Tang, Shaoxun; Zhou, Chuanshe; Tan, Zhiliang; Forster, Robert J.

2017-01-01

The objective of this present study was to explore the initial establishment of metabolically active bacteria and subsequent evolution in four fractions: rumen solid-phase (RS), liquid-phase (RL), protozoa-associated (RP), and epithelium-associated (RE) through early weaning and supplementing rhubarb root powder in 7 different age groups (1, 10, 20, 38, 41, 50, and 60 d) during rumen development. Results of the 16S rRNA sequencing based on RNA isolated from the four fractions revealed that the potentially active bacterial microbiota in four fractions were dominated by the phyla Proteobacteria, Firmicutes, and Bacteroidetes regardless of different ages. An age-dependent increment of Chao 1 richness was observed in the fractions of RL and RE. The principal coordinate analysis (PCoA) indicated that samples in four fractions all clustered based on different age groups, and the structure of the bacterial community in RE was distinct from those in other three fractions. The abundances of Proteobacteria decreased significantly (P < 0.05) with age, while increases in the abundances of Firmicutes and Bacteroidetes were noted. At the genus level, the abundance of the predominant genus Mannheimia in the Proteobacteria phylum decreased significantly (P < 0.05) after 1 d, while the genera Quinella, Prevotella, Fretibacterium, Ruminococcus, Lachnospiraceae NK3A20 group, and Atopobium underwent different manners of increases and dominated the bacterial microbiota across four fractions. Variations of the distributions of some specific bacterial genera across fractions were observed, and supplementation of rhubarb affected the relative abundance of various genera of bacteria. PMID:28223972

Biosynthesis of fluorescent CdS nanocrystals with semiconductor properties: Comparison of microbial and plant production systems.

PubMed

Al-Shalabi, Zahwa; Doran, Pauline M

2016-04-10

This study investigated fission yeast (Schizosaccharomyces pombe) and hairy roots of tomato (Solanum lycopersicum) as in vitro production vehicles for biological synthesis of CdS quantum dots. Cd added during the mid-growth phase of the cultures was detoxified within the biomass into inorganic sulphide-containing complexes with the quantum confinement properties of semiconductor nanocrystals. Significant differences were found between the two host systems in terms of nanoparticle production kinetics, yield and quality. The much slower growth rate of hairy roots compared with yeast is a disadvantage for commercial scaled-up production. Nanoparticle extraction from the biomass was less effective for the roots: 19% of the Cd present in the hairy roots was recovered after extraction compared with 34% for the yeast. The overall yield of CdS quantum dots was also lower for the roots: relative to the amount of Cd taken up into the biomass, 8.5% was recovered in yeast gel filtration fractions exhibiting quantum dot properties whereas the result for hairy roots was only 0.99%. Yeast-produced CdS crystallites were somewhat smaller with diameters of approximately 2-6 nm compared with those of 4-10nm obtained from the roots. The average ratio of inorganic sulphide to Cd for the purified and size-fractionated particles was 0.44 for the yeast and 1.6 for the hairy roots. Despite the limitations associated with hairy roots in terms of culture kinetics and product yield, this system produced CdS nanoparticles with enhanced photostability and 3.7-13-fold higher fluorescence quantum efficiency compared with those generated by yeast. This work demonstrates that the choice of cellular host can have a significant effect on nanoparticle functional properties as well as on the bioprocessing aspects of biological quantum dot synthesis. Copyright © 2016 Elsevier B.V. All rights reserved.

A scanning electron microscopy study of diseased root surfaces conditioned with EDTA gel plus Cetavlon after scaling and root planing.

PubMed

Martins Júnior, Walter; De Rossi, Andiara; Samih Georges Abi Rached, Ricardo; Rossi, Marcos Antonio

2011-01-01

In the present investigation, a scanning electron microscopy analysis was performed to evaluate the effects of the topical application of ethylenediaminetetraacetic acid (EDTA) gel associated with Cetavlon (EDTAC) in removing the smear layer and exposing collagen fibers following root surface instrumentation. Twenty-eight teeth from adult humans, single rooted and scheduled for extraction due to periodontal reasons, were selected. Each tooth was submitted to manual (scaling and root planing) instrumentation alone or combined with ultrasonic instruments, with or without etching using a 24% EDTAC gel. Following extraction, specimens were processed and examined under a scanning electron microscope. A comparative morphological semi-quantitative analysis was performed; the intensity of the smear layer and the decalcification of cementum and dentinal surfaces were graded in 12 sets using an arbitrary scale ranging from 1 (area covered by a smear layer) to 4 (no smear layer). Root debridement with hand instruments alone or combined with ultrasonic instruments resulted in a similar smear layer covering the root surfaces. The smear layer was successfully removed from the surfaces treated with EDTAC, which exhibited numerous exposed dentinal tubules and collagen fibers. This study supports the hypothesis that manual instrumentation alone or instrumentation combined with ultrasonic instrumentation is unable to remove the smear layer, whereas the subsequent topical application of EDTAC gel effectively removes the smear layer, uncovers dentinal openings and exposes collagen fibers.

Phytochemical Characterization of Low Molecular Weight Constituents from Marshmallow Roots (Althaea officinalis) and Inhibiting Effects of the Aqueous Extract on Human Hyaluronidase-1.

PubMed

Sendker, Jandirk; Böker, Ines; Lengers, Isabelle; Brandt, Simone; Jose, Joachim; Stark, Timo; Hofmann, Thomas; Fink, Careen; Abdel-Aziz, Heba; Hensel, Andreas

2017-02-24

Extract RE was obtained from the roots of Althaea officinalis in a yield of 8.1%, related to the dried plant material, by extraction with MeOH-H 2 O (1:1), followed by precipitation with EtOH to remove high molecular weight constituents. Phytochemical investigation of RE revealed the presence of N-phenylpropenoyl-l-amino acid amides 1-5, 8% glycine betaine 6, about 9% total amino acids with proline as the main compound, and about 61% mono- and oligomeric carbohydrates with sucrose as the main compound. Further fractionation revealed the presence of a hypolaetin diglycoside (12) and four hypolaetin glycosides (7-9 and 11) with O-sulfocarbohydrate moieties; additionally, 4'-O-methylisoscutellarein-8-O-β-d-(3″-O-sulfo)glucuronopyranoside (10) and the diglycosylated coumarin haploperoside D (13) were identified. The hypolaetin-O-sulfoglycosides 7-10 are new natural products. RE inhibited the enzymatic activity of surface-displayed human hyaluronidase-1 on Escherichia coli F470 cells with an IC 50 of 7.7 mg/mL. RE downregulated mRNA expression of hyal-1 in HaCaT keratinocytes at 125 and 250 μg/mL, respectively. These data contribute to a deeper phytochemical understanding of marshmallow root extracts and to the positive influence of extracts used for therapy of irritated and inflamed buccal tissue and cough.

Salts affect the interaction of ZnO or CuO nanoparticles with wheat.

PubMed

Stewart, Jacob; Hansen, Trevor; McLean, Joan E; McManus, Paul; Das, Siddhartha; Britt, David W; Anderson, Anne J; Dimkpa, Christian O

2015-09-01

Exposure to nanoparticles (NPs) that release metals with potential phytotoxicity could pose problems in agriculture. The authors of the present study used growth in a model growth matrix, sand, to examine the influence of 5 mmol/kg of Na, K, or Ca (added as Cl salts) and root exudates on transformation and changes to the bioactivity of copper(II) oxide (CuO) and zinc oxide (ZnO) NPs on wheat. These salt levels are found in saline agricultural soils. After 14 d of seedling growth, particles with crystallinity typical of CuO or ZnO remained in the aqueous fraction from the sand; particles had negative surface charges that differed with NP type and salt, but salt did not alter particle agglomeration. Reduction in shoot and root elongation and lateral root induction by ZnO NPs were mitigated by all salts. However, whereas Na and K promoted Zn loading into shoots, Ca reduced loading, suggesting that competition with Zn ions for uptake occurred. With CuO NPs, plant growth and loading was modified equally by all salts, consistent with major interaction with the plant with CuO rather than Cu ions. Thus, for both NPs, loading into plant tissues was not solely dependent on ion solubility. These findings indicated that salts in agricultural soils could modify the phytotoxicity of NPs. © 2015 SETAC.

Plant-mediated effects on extracellular enzyme activities in distinct soil aggregate size classes in field

NASA Astrophysics Data System (ADS)

Kumar, Amit; Dorodnikov, Maxim; Splettstößer, Thomas; Kuzyakov, Yakov; Pausch, Johanna

2017-04-01

Soil aggregation and microbial activities within the aggregates are important factors regulating soil carbon (C) turnover. A reliable and sensitive proxy for microbial activity is activity of extracellular enzymes (EEA). In the present study, effects of soil aggregates on EEA were investigated under three maize plant densities (Low, Normal, and High). Bulk soil was fractionated into three aggregate size classes (>2000 µm large macroaggregates; 2000-250 µm small macroaggregates; <250 µm microaggregates) by optimal-moisture sieving. Microbial biomass and EEA (β-1,4-glucosidase (BG), β-1,4-N-acetylglucosaminidase (NAG), L-leucine aminopeptidase (LAP) and acid phosphatase (acP)) catalyzing soil organic matter (SOM) decomposition were measured in rooted soil of maize and soil from bare fallow. Microbial biomass C (Cmic) decreased with decreasing aggregate size classes. Potential and specific EEA (per unit of Cmic) increased from macro- to microaggregates. In comparison with bare fallow soil, specific EEA of microaggregates in rooted soil was higher by up to 73%, 31%, 26%, and 92% for BG, NAG, acP and LAP, respectively. Moreover, high plant density decreased macroaggregates by 9% compared to bare fallow. Enhanced EEA in three aggregate size classes demonstrated activation of microorganisms by roots. Strong EEA in microaggregates can be explained by microaggregates' localization within the soil. Originally adhering to surfaces of macroaggregates, microaggregates were preferentially exposed to C substrates and nutrients, thereby promoting microbial activity.

Stable Ca Isotopes in Tamarix aphylla Tree Rings, Death Valley, California

NASA Astrophysics Data System (ADS)

Yang, W.; Depaolo, D. J.; Ingram, B. L.; Owens, T. L.

2008-12-01

As a dune stabilizer and windbreak, Tamarix aphylla is an exotic perennial and evergreen tree in Death Valley. Its tap roots can reach down to 30 m depth and sub-superficial side roots may reach 50 m horizontally. The species can store large amounts of water in its roots and undergoes high evapotranspiration. Since Tamarix aphylla is a perennial tree growing in desert environments and its roots reach deep to the water table, it could be a proxy for desert ecological and hydrologic systems through time. We measured Ca isotopes in the soluble fraction of 8 tree ring samples from a 50-year-old specimen growing on an alluvial fan in Death Valley near Furnace Creek. Previous studies (Yang et al, GCA 60, 1996) indicate that this tree's rings contain high sulfur concentrations (4-6% expressed as sulfate) with chemical composition of CaSO4 (0.15-0.62 H2O). The δ34S values of soluble sulfate increase from +13.5 to +18 permil VCDT from the core to the bark, which are interpreted as reflecting deeper sulfate sources as the tree grew. The δ13C variations of the tree-ring cellulose (-27.6 to -24.0 permil VPDB) reflect changes in the local precipitation and show that Tamarix aphylla undergoes C3 photosynthesis. The δ44Ca for the soluble sulfate Ca through the tree-ring section, which covers a time period from 1945 to 1993, have an average value -2.52 permil (-3.4 permil relative to seawater). Only small variations are observed, from -2.69 to -2.28; the highest value (for 1990) occurs near the end of an extended drought. These are the first measurements of tree rings, but the low δ44Ca values are consistent with previous measurements of beech roots and stems from a temperate forest (Page et al., Biogeochem. 88, 2008). In our case, the tree has only one Ca source, which is expected to be isotopically uniform and similar to both local rainfall and limestones (δ44Ca ~ -0.6 permil), and with the minimal vegetation and extensive deep root system it is unlikely that there is a significant depletion of soil Ca due to plant uptake. Thus the Ca isotopic fractionation between trunk and source (ΔCa = -2 permil) is clearly defined by the data. By analogy to the results of Page et al., the Ca fractionation between root and source may be larger (ΔCa ~ -3 permil). This biological Ca isotope fractionation is no doubt due to transport processes during root uptake of Ca, but the magnitude is significantly larger than that observed for inorganic processes such as mineral precipitation or aqueous diffusion. The slight increase in δ44Ca in drought conditions suggests that when the tree is stressed there may be less Ca isotope fractionation, either because the Ca is held more tightly in small pores in the soil, or because the available Ca pool shrinks such that the soil Ca starts to shift to more positive δ44Ca values due to depletion of light Ca by the plant. The slowly accumulating database on Ca isotopes in plants continues to suggest that systematic Ca isotope studies may be fruitful for understanding cation transport in plants, and soil ecological conditions in general.

Computing the Partial Fraction Decomposition of Rational Functions with Irreducible Quadratic Factors in the Denominators

ERIC Educational Resources Information Center

Man, Yiu-Kwong

2012-01-01

In this note, a new method for computing the partial fraction decomposition of rational functions with irreducible quadratic factors in the denominators is presented. This method involves polynomial divisions and substitutions only, without having to solve for the complex roots of the irreducible quadratic polynomial or to solve a system of linear…

Improving soil moisture simulation to support Agricultural Water Resource Management using Satellite-based water cycle observations

NASA Astrophysics Data System (ADS)

Gupta, Manika; Bolten, John; Lakshmi, Venkat

2016-04-01

Efficient and sustainable irrigation systems require optimization of operational parameters such as irrigation amount which are dependent on the soil hydraulic parameters that affect the model's accuracy in simulating soil water content. However, it is a scientific challenge to provide reliable estimates of soil hydraulic parameters and irrigation estimates, given the absence of continuously operating soil moisture and rain gauge network. For agricultural water resource management, the in-situ measurements of soil moisture are currently limited to discrete measurements at specific locations, and such point-based measurements do not represent the spatial distribution at a larger scale accurately, as soil moisture is highly variable both spatially and temporally (Wang and Qu 2009). In the current study, flood irrigation scheme within the land surface model is triggered when the root-zone soil moisture deficit reaches below a threshold of 25%, 50% and 75% with respect to the maximum available water capacity (difference between field capacity and wilting point) and applied until the top layer is saturated. An additional important criterion needed to activate the irrigation scheme is to ensure that it is irrigation season by assuming that the greenness vegetation fraction (GVF) of the pixel exceed 0.40 of the climatological annual range of GVF (Ozdogan et al. 2010). The main hypothesis used in this study is that near-surface remote sensing soil moisture data contain useful information that can describe the effective hydrological conditions of the basin such that when appropriately inverted, it would provide field capacity and wilting point soil moisture, which may be representative of that basin. Thus, genetic algorithm inverse method is employed to derive the effective parameters and derive the soil moisture deficit for the root zone by coupling of AMSR-E soil moisture with the physically based hydrological model. Model performance is evaluated using MODIS-evapotranspiration (ET) and MODIS land surface temperature (LST) products. The soil moisture estimates for the root zone are also validated with the in-situ field data, for three sites (2- irrigated and 1- rainfed) located at the University of Nebraska Agricultural Research and Development Center near Mead, NE and monitored by three AmeriFlux installations (Verma et al., 2005) by evaluating the root mean square error (RMSE) and Mean Bias error (MBE).

Tissue fractions of cadmium in two hyperaccumulating Jerusalem artichoke genotypes.

PubMed

Long, Xiaohua; Ni, Ni; Liu, Zhaopu; Rengel, Zed; Jiang, Xin; Shao, Hongbo

2014-01-01

In order to investigate the mechanisms in two Jerusalem artichoke (Helianthus tuberosus L.) genotypes that hyperaccumulate Cd, a sand-culture experiment was carried out to characterize fractionation of Cd in tissue of Cd-hyperaccumulating genotypes NY2 and NY5. The sequential extractants were: 80% v/v ethanol (FE), deionized water (FW), 1 M NaCl (FNaCl), 2% v/v acetic acid (FAcet), and 0.6 M HCl (FHCl). After 20 days of treatments, NY5 had greater plant biomass and greater Cd accumulation in tissues than NY2. In both genotypes the FNaCl fraction was the highest in roots and stems, whereas the FAcet and FHCl fractions were the highest in leaves. With an increase in Cd concentration in the culture solution, the content of every Cd fraction also increased. The FW and FNaCl ratios in roots were lower in NY5 than in NY2, while the amount of other Cd forms was higher. It implied that, in high accumulator, namely, NY5, the complex of insoluble phosphate tends to be shaped more easily which was much better for Cd accumulation. Besides, translocation from plasma to vacuole after combination with protein may be one of the main mechanisms in Cd-accumulator Jerusalem artichoke genotypes.

Tissue Fractions of Cadmium in Two Hyperaccumulating Jerusalem Artichoke Genotypes

PubMed Central

Long, Xiaohua; Ni, Ni; Liu, Zhaopu; Rengel, Zed; Jiang, Xin; Shao, Hongbo

2014-01-01

In order to investigate the mechanisms in two Jerusalem artichoke (Helianthus tuberosus L.) genotypes that hyperaccumulate Cd, a sand-culture experiment was carried out to characterize fractionation of Cd in tissue of Cd-hyperaccumulating genotypes NY2 and NY5. The sequential extractants were: 80% v/v ethanol (FE), deionized water (FW), 1 M NaCl (FNaCl), 2% v/v acetic acid (FAcet), and 0.6 M HCl (FHCl). After 20 days of treatments, NY5 had greater plant biomass and greater Cd accumulation in tissues than NY2. In both genotypes the FNaCl fraction was the highest in roots and stems, whereas the FAcet and FHCl fractions were the highest in leaves. With an increase in Cd concentration in the culture solution, the content of every Cd fraction also increased. The FW and FNaCl ratios in roots were lower in NY5 than in NY2, while the amount of other Cd forms was higher. It implied that, in high accumulator, namely, NY5, the complex of insoluble phosphate tends to be shaped more easily which was much better for Cd accumulation. Besides, translocation from plasma to vacuole after combination with protein may be one of the main mechanisms in Cd-accumulator Jerusalem artichoke genotypes. PMID:24883399

Water flow and solute transport in floating fen root mats

NASA Astrophysics Data System (ADS)

Stofberg, Sija F.; EATM van der Zee, Sjoerd

2015-04-01

Floating fens are valuable wetlands, found in North-Western Europe, that are formed by floating root mats when old turf ponds are colonized by plants. These terrestrialization ecosystems are known for their biodiversity and the presence of rare plant species, and the root mats reveal different vegetation zones at a small scale. The vegetation zones are a result of strong gradients in abiotic conditions, including groundwater dynamics, nutrients and pH. To prevent irreversible drought effects such as land subsidence and mineralization of peat, water management involves import of water from elsewhere to maintain constant surface water levels. Imported water may have elevated levels of salinity during dry summers, and salt exposure may threaten the vegetation. To assess the risk of exposure of the rare plant species to salinity, the hydrology of such root mats must be understood. Physical properties of root mats have scarcely been investigated. We have measured soil characteristics, hydraulic conductivity, vertical root mat movement and groundwater dynamics in a floating root mat in the nature reserve Nieuwkoopse Plassen, in the Netherlands. The root mat mostly consists of roots and organic material, in which the soil has a high saturated water content, and strongly varies in its stage of decomposition. We have found a distinct negative correlation between degree of decomposition and hydraulic conductivity, similar to observations for bogs in the literature. Our results show that the relatively young, thin edge of the root mat that colonizes the surface water has a high hydraulic conductivity and floats in the surface water, resulting in very small groundwater fluctuations within the root mat. The older part of the root mat, that is connected to the deeper peat layers is hydrologically more isolated and the material has a lower conductivity. Here, the groundwater fluctuates strongly with atmospheric forcing. The zones of hydraulic properties and vegetation, appear to be very similar and likely functionally related. Our experimental field data were used for modelling water flow and solute transport in floating fens, using HYDRUS 2D. Fluctuations of surface water and root mat, as well as geometry and unsaturated zone parameters can have a major influence on groundwater fluctuations and the exchange between rain and surface water and the water in the root mats. In combination with the duration of salt pulses in surface water, and sensitivity of fen plants to salinity (Stofberg et al. 2014, submitted), risks for rare plants can be anticipated.

Isolation of a novel mutant gene for soil-surface rooting in rice (Oryza sativa L.)

PubMed Central

2013-01-01

Background Root system architecture is an important trait affecting the uptake of nutrients and water by crops. Shallower root systems preferentially take up nutrients from the topsoil and help avoid unfavorable environments in deeper soil layers. We have found a soil-surface rooting mutant from an M2 population that was regenerated from seed calli of a japonica rice cultivar, Nipponbare. In this study, we examined the genetic and physiological characteristics of this mutant. Results The primary roots of the mutant showed no gravitropic response from the seedling stage on, whereas the gravitropic response of the shoots was normal. Segregation analyses by using an F2 population derived from a cross between the soil-surface rooting mutant and wild-type Nipponbare indicated that the trait was controlled by a single recessive gene, designated as sor1. Fine mapping by using an F2 population derived from a cross between the mutant and an indica rice cultivar, Kasalath, revealed that sor1 was located within a 136-kb region between the simple sequence repeat markers RM16254 and 2935-6 on the terminal region of the short arm of chromosome 4, where 13 putative open reading frames (ORFs) were found. We sequenced these ORFs and detected a 33-bp deletion in one of them, Os04g0101800. Transgenic plants of the mutant transformed with the genomic fragment carrying the Os04g0101800 sequence from Nipponbare showed normal gravitropic responses and no soil-surface rooting. Conclusion These results suggest that sor1, a rice mutant causing soil-surface rooting and altered root gravitropic response, is allelic to Os04g0101800, and that a 33-bp deletion in the coding region of this gene causes the mutant phenotypes. PMID:24280269

Isolation of a novel mutant gene for soil-surface rooting in rice (Oryza sativa L.).

PubMed

Hanzawa, Eiko; Sasaki, Kazuhiro; Nagai, Shinsei; Obara, Mitsuhiro; Fukuta, Yoshimichi; Uga, Yusaku; Miyao, Akio; Hirochika, Hirohiko; Higashitani, Atsushi; Maekawa, Masahiko; Sato, Tadashi

2013-11-20

Root system architecture is an important trait affecting the uptake of nutrients and water by crops. Shallower root systems preferentially take up nutrients from the topsoil and help avoid unfavorable environments in deeper soil layers. We have found a soil-surface rooting mutant from an M2 population that was regenerated from seed calli of a japonica rice cultivar, Nipponbare. In this study, we examined the genetic and physiological characteristics of this mutant. The primary roots of the mutant showed no gravitropic response from the seedling stage on, whereas the gravitropic response of the shoots was normal. Segregation analyses by using an F2 population derived from a cross between the soil-surface rooting mutant and wild-type Nipponbare indicated that the trait was controlled by a single recessive gene, designated as sor1. Fine mapping by using an F2 population derived from a cross between the mutant and an indica rice cultivar, Kasalath, revealed that sor1 was located within a 136-kb region between the simple sequence repeat markers RM16254 and 2935-6 on the terminal region of the short arm of chromosome 4, where 13 putative open reading frames (ORFs) were found. We sequenced these ORFs and detected a 33-bp deletion in one of them, Os04g0101800. Transgenic plants of the mutant transformed with the genomic fragment carrying the Os04g0101800 sequence from Nipponbare showed normal gravitropic responses and no soil-surface rooting. These results suggest that sor1, a rice mutant causing soil-surface rooting and altered root gravitropic response, is allelic to Os04g0101800, and that a 33-bp deletion in the coding region of this gene causes the mutant phenotypes.

Evaluation of Root Canal Preparation Using Rotary System and Hand Instruments Assessed by Micro-Computed Tomography

PubMed Central

Stavileci, Miranda; Hoxha, Veton; Görduysus, Ömer; Tatar, Ilkan; Laperre, Kjell; Hostens, Jeroen; Küçükkaya, Selen; Muhaxheri, Edmond

2015-01-01

Background Complete mechanical preparation of the root canal system is rarely achieved. Therefore, the purpose of this study was to evaluate and compare the root canal shaping efficacy of ProTaper rotary files and standard stainless steel K-files using micro-computed tomography. Material/Methods Sixty extracted upper second premolars were selected and divided into 2 groups of 30 teeth each. Before preparation, all samples were scanned by micro-computed tomography. Thirty teeth were prepared with the ProTaper system and the other 30 with stainless steel files. After preparation, the untouched surface and root canal straightening were evaluated with micro-computed tomography. The percentage of untouched root canal surface was calculated in the coronal, middle, and apical parts of the canal. We also calculated straightening of the canal after root canal preparation. Results from the 2 groups were statistically compared using the Minitab statistical package. Results ProTaper rotary files left less untouched root canal surface compared with manual preparation in coronal, middle, and apical sector (p<0.001). Similarly, there was a statistically significant difference in root canal straightening after preparation between the techniques (p<0.001). Conclusions Neither manual nor rotary techniques completely prepared the root canal, and both techniques caused slight straightening of the root canal. PMID:26092929

Evaluation of Root Canal Preparation Using Rotary System and Hand Instruments Assessed by Micro-Computed Tomography.

PubMed

Stavileci, Miranda; Hoxha, Veton; Görduysus, Ömer; Tatar, Ilkan; Laperre, Kjell; Hostens, Jeroen; Küçükkaya, Selen; Muhaxheri, Edmond

2015-06-20

Complete mechanical preparation of the root canal system is rarely achieved. Therefore, the purpose of this study was to evaluate and compare the root canal shaping efficacy of ProTaper rotary files and standard stainless steel K-files using micro-computed tomography. Sixty extracted upper second premolars were selected and divided into 2 groups of 30 teeth each. Before preparation, all samples were scanned by micro-computed tomography. Thirty teeth were prepared with the ProTaper system and the other 30 with stainless steel files. After preparation, the untouched surface and root canal straightening were evaluated with micro-computed tomography. The percentage of untouched root canal surface was calculated in the coronal, middle, and apical parts of the canal. We also calculated straightening of the canal after root canal preparation. Results from the 2 groups were statistically compared using the Minitab statistical package. ProTaper rotary files left less untouched root canal surface compared with manual preparation in coronal, middle, and apical sector (p<0.001). Similarly, there was a statistically significant difference in root canal straightening after preparation between the techniques (p<0.001). Neither manual nor rotary techniques completely prepared the root canal, and both techniques caused slight straightening of the root canal.

Effect of root planing on surface topography: an in-vivo randomized experimental trial.

PubMed

Rosales-Leal, J I; Flores, A B; Contreras, T; Bravo, M; Cabrerizo-Vílchez, M A; Mesa, F

2015-04-01

The root surface topography exerts a major influence on clinical attachment and bacterial recolonization after root planing. In-vitro topographic studies have yielded variable results, and clinical studies are necessary to compare root surface topography after planing with current ultrasonic devices and with traditional manual instrumentation. The aim of this study was to compare the topography of untreated single-rooted teeth planed in vivo with a curette, a piezoelectric ultrasonic (PU) scraper or a vertically oscillating ultrasonic (VOU) scraper. In a randomized experimental trial of 19 patients, 44 single-rooted teeth were randomly assigned to one of four groups for: no treatment; manual root planing with a curette; root planing with a PU scraper; or root planing with a VOU scraper. Post-treatment, the teeth were extracted and their topography was analyzed in 124 observations with white-light confocal microscopy, measuring the roughness parameters arithmetic average height, root-mean-square roughness, maximum height of peaks, maximum depth of valleys, absolute height, skewness and kurtosis. The roughness values arithmetic average height and root-mean-square roughness were similar after each treatment and lower than after no treatment ( p < 0.05). Absolute height was lower in the VOU group than in the untreated ( p = 0.0026) and PU (p = 0.045) groups. Surface morphology was similar after the three treatments and was less irregular than in the untreated group. Values for the remaining roughness parameters were similar among all treatment groups ( p > 0.05). Both ultrasonic devices reduce the roughness, producing a similar topography to that observed after manual instrumentation with a curette, to which they appear to represent a valid alternative. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

In vitro radicular temperatures produced by injectable thermoplasticized gutta-percha.

PubMed

Weller, R N; Koch, K A

1995-03-01

In vitro temperatures produced in the root canal and on the root surface were measured simultaneously as heated gutta-percha was injected into the prepared canal. The canals were obturated with the Obtura II heated gutta-percha system with temperature settings of 160, 185, and 200 degrees C. The mean intracanal temperatures ranged from 40.21 to 57.24 degrees C, whereas the mean root surface temperatures were recorded from 37.22 to 41.90 degrees C for all three temperatures tested. The rise in temperature on the root surface was below the critical level of 10 degrees C and should not cause damage to the periodontal ligament.

Thermal and microstructural effects of nanosecond pulsed Nd:YAG laser irradiation on tooth root surface

NASA Astrophysics Data System (ADS)

Wilder-Smith, Petra B. B.; Arrastia-Jitosho, Anna-Marie A.; Grill, G.; Liaw, Lih-Huei L.; Berns, Michael W.

1995-05-01

Plaque, calculus and altered cementum removal by scaling and root planing is a fundamental procedure in periodontal treatment. However, the residual smear layer contains cytotoxic and inflammatory mediators which adversely affect healing. Chemical smear layer removal is also problematic. In previous investigations effective smear layer removal was achieved using long pulsed irradiation at 1.06 (mu) . However, laser irradiation was not adequate as an alternative to scaling and root planing procedures and concurrent temperature rises exceeded thermal thresholds for pulpal and periodontal safety. It was the aim of this study to determine whether nanosecond pulsed irradiation at 1.06 (mu) could be used as an alternative or an adjunct to scaling and root planing. Sixty freshly extracted teeth were divided as follows: 5 control, 5 root planed only, 25 irradiated only, 25 root planed and irradiated. Irradiation was performed at fluences of 0.5 - 2.7 J/cm2, total energy densities of 12 - 300 J/cm2, frequencies of 2 - 10 Hz using the Medlite (Continuum) laser. Irradiation-induced thermal events were recorded using a thermocouple within the root canal and a thermal camera to monitor surface temperatures. SEM demonstrated effective smear layer removal with minimal microstructural effects. Surface temperatures increased minimally (< 3 C) at all parameters, intrapulpal temperature rises remained below 4 C at 2 and 5 Hz, F < 0.5 J/cm2. Without prior scaling and root planing, laser effects did not provide an adequately clean root surface.

Automated quantification of surface water inundation in wetlands using optical satellite imagery

USGS Publications Warehouse

DeVries, Ben; Huang, Chengquan; Lang, Megan W.; Jones, John W.; Huang, Wenli; Creed, Irena F.; Carroll, Mark L.

2017-01-01

We present a fully automated and scalable algorithm for quantifying surface water inundation in wetlands. Requiring no external training data, our algorithm estimates sub-pixel water fraction (SWF) over large areas and long time periods using Landsat data. We tested our SWF algorithm over three wetland sites across North America, including the Prairie Pothole Region, the Delmarva Peninsula and the Everglades, representing a gradient of inundation and vegetation conditions. We estimated SWF at 30-m resolution with accuracies ranging from a normalized root-mean-square-error of 0.11 to 0.19 when compared with various high-resolution ground and airborne datasets. SWF estimates were more sensitive to subtle inundated features compared to previously published surface water datasets, accurately depicting water bodies, large heterogeneously inundated surfaces, narrow water courses and canopy-covered water features. Despite this enhanced sensitivity, several sources of errors affected SWF estimates, including emergent or floating vegetation and forest canopies, shadows from topographic features, urban structures and unmasked clouds. The automated algorithm described in this article allows for the production of high temporal resolution wetland inundation data products to support a broad range of applications.

Root gravitropism in maize and Arabidopsis

NASA Technical Reports Server (NTRS)

Evans, Michael L.

1993-01-01

Research during the period 1 March 1992 to 30 November 1993 focused on improvements in a video digitizer system designed to automate the recording of surface extension in plants responding to gravistimulation. The improvements included modification of software to allow detailed analysis of localized extension patterns in roots of Arabidopsis. We used the system to analyze the role of the postmitotic isodiametric growth zone (a region between the meristem and the elongation zone) in the response of maize roots to auxin, calcium, touch and gravity. We also used the system to analyze short-term auxin and gravitropic responses in mutants of Arabidopsis with reduced auxin sensitivity. In a related project, we studied the relationship between growth rate and surface electrical currents in roots by examining the effects of gravity and thigmostimulation on surface potentials in maize roots.

Effects of erbium, chromium:YSGG laser irradiation on root surface: morphological and atomic analytical studies.

PubMed

Kimura, Y; Yu, D G; Kinoshita, J; Hossain, M; Yokoyama, K; Murakami, Y; Nomura, K; Takamura, R; Matsumoto, K

2001-04-01

The purpose of this study was to investigate the morphological and atomic changes on the root surface by stereoscopy, field emission-scanning electron microscopy (FE-SEM), and energy dispersive X-ray spectroscopy (SEM-EDX) after erbium, chromium:yttrium, scandium, gallium, garnet (Er,Cr:YSGG) laser irradiation in vitro. There have been few reports on morphological and atomic analytical study on root surface by Er,Cr:YSGG laser irradiation. Eighteen extracted human premolar and molar teeth were irradiated on root surfaces at a vertical position with water-air spray by an Er,Cr:YSGG laser at the parameter of 5.0 W and 20 Hz for 5 sec while moving. The samples were then morphologically observed by stereoscopy and FE-SEM and examined atomic-analytically by SEM-EDX. Craters having rough but clean surfaces and no melting or carbonization were observed in the samples. An atomic analytical examination showed that the calcium ratio to phosphorus showed no significant changes between the control and irradiated areas (p > 0.01). These results showed that the Er,Cr:YSGG laser has a good cutting effect on root surface and causes no burning or melting after laser irradiation.

Listeria monocytogenes - Danger for health safety vegetable production.

PubMed

Kljujev, Igor; Raicevic, Vera; Jovicic-Petrovic, Jelena; Vujovic, Bojana; Mirkovic, Milica; Rothballer, Michael

2018-04-22

The microbiologically contaminated vegetables represent a risk for consumers, especially vegetables without thermal processing. It is known that human pathogen bacteria, such as Listeria monocytogenes, could exist on fresh vegetables. The fresh vegetables could become Listeria-contaminated if they come in touch with contaminated soil, manure, irrigation water. The aim of this work was to investigate the presence of Listeria spp. and L. monocytogenes in different kind of vegetables grown in field and greenhouse condition as well as surface and endophytic colonization plant roots of different vegetables species by L. monocytogenes in laboratory conditions. The detection of Listeria spp. and L. monocytogenes in vegetable samples was done using ISO and PCR methods. The investigation of colonization vegetable roots and detection Listeria-cells inside plant root tissue was done using Fluorescence in situ hybridization (FISH) method in combination with confocal laser scanning microscopy (CLSM). The results showed that 25.58% vegetable samples were positive for Listeria spp. and only one sample (carrot) was positive for L. monocytogenes out of 43 samples in total collected from field and greenhouse. The strain L. monocytogenes EGD-E surface and endophytic colonized carrot root in highest degree while strain L. monocytogenes SV4B was the most represented at leafy vegetable plants, such at lettuce (1.68 × 10 6  cells/mm 3 absolutely dry root) and spinach (1.39 × 10 6  cells/mm 3 absolutely dry root) root surface. The cells of L. monocytogenes SV4B were visible as single cells in interior tissue of plant roots (celery and sweet corn roots) as well as in the interior of the plant root cell at sweet corn root. The cells of L. monocytogenes EGD-E bind to the surface of the plant root and they were less commonly found out on root hair. In the inner layers of the root, those bacterial cells were inhabited intercellular spaces mainly as single cells very close to the larval vessels of root. Our results suggest that L. monocytogenes is very good endophytic colonizer of vegetable plant roots. Copyright © 2018 Elsevier Ltd. All rights reserved.

Interaction between U and Th on their uptake, distribution, and toxicity in V S. alfredii based on the phytoremediation of U and Th.

PubMed

Huang, Zhenling; Tang, Siqun; Zhang, Lu; Ma, Lijian; Ding, Songdong; Du, Liang; Zhang, Dong; Jin, Yongdong; Wang, Ruibing; Huang, Chao; Xia, Chuanqin

2017-01-01

Variant Sedum alfredii Hance (V S. alfredii) could simultaneously take up U and Th from water with the highest concentrations recorded as 1.84 × 10 4 and 6.72 × 10 3  mg/kg in the roots, respectively. Th stimulated U uptake by V S. alfredii roots at Th 10 (10 μM of Th), however, the opposite was observed at Th 100 (100 μM of Th). A similar result was found in the effect of U on the uptake of Th by V S. alfredii. Subcellular fractionation studies of V S. alfredii indicated that U and Th were mainly stored in cell wall fraction, and much less was found in organelle and soluble fractions. Chemical form examination results showed that water-soluble U and Th were the predominant chemical forms in this plant. Addition of the other radionuclide in aqueous solutions altered the concentration and percentage of U or Th in cell wall fraction and in water-soluble form, resulting in the change of the uptake capacity of U or Th by V S. alfredii roots. Comparing with single U or Th treatment, the plant cells revealed more swollen chloroplasts and enhanced thickening in cell walls under the U 100  + Th 100 treatment, as observed by TEM. Those results collectively displayed that V S. alfredii may be utilized as a potential plant to simultaneously remove U and Th from aqueous solutions (rhizofiltration).

Modulatory effects by neodymium-doped yttrium aluminum garnet laser on fibroblast attachment to single rooted tooth surfaces following ultrasonic scaling and root planning: An in vitro study

PubMed Central

Negi, Shanta; Krishnamurthy, Malathi; Ganji, Kiran Kumar; Pendor, Sunil

2015-01-01

Context: One of the most important goals of periodontal therapy is connective tissue reattachment to previously diseased root surfaces. In the recent years, laser therapy has been considered as an important tool in improving the treatment of periodontal disease. Aims: To evaluate the neodymium-doped yttrium aluminum garnet (Nd: YAG) lasers effects on root surfaces affected by periodontal disease and compare this treatment with scaling and root planning (SRP) in terms of fibroblast attachment. Materials and Methods: A sample of 30 single-rooted human teeth extracted because of advanced periodontal disease was used in this study. Sixty specimens obtained by longitudinal sectioning were randomly divided in three groups. Group A control (untreated); Group B SRP; Group C laser (Nd: YAG) and ultrasonic scaling. All specimens were incubated with fibroblast suspension and then fixed and observed under scanning electron microscope. Results: With a median of 8, the control group (Group A) exhibited the least number of total fibroblasts among all the three groups. The laser and scaling - treated group (Group C) showed the highest number of fibroblasts (median = 49, mean ± standard deviation [SD] = 48.28 ± 17.18), followed by SRP only (Group B, median = 22, mean ± SD = 22.24 ± 8.67). Conclusions: Nd: YAG laser irradiation at specific energy densities can be used as a useful tool to condition the root surfaces, enhancing fibroblast attachment. Hence aiding in re-establishment of the connective tissue attachment to the root surfaces of previously diseased teeth. PMID:25810589

Root Surface Biomodification with Nd:YAG Laser for the Treatment of Gingival Recession with Subepithelial Connective Tissue Grafts

PubMed Central

Aydin, Tugba; Canakci, Varol; Cicek, Yasin

2010-01-01

Abstract Background/Aim: Root surface biomodification has been used to treat gingival recession and periodontitis. The principle for this procedure is that removing the smear layer from the root surfaces exposes collagen fibers, which leads to improved healing. Clinical studies generally have failed to find any improvement in clinical parameters when using such procedures, however. The aim of this study was to evaluate and compare the outcome of gingival recession therapy using the subepithelial connective tissue graft (SCTG) with or without Nd:YAG laser application for root surface biomodification. Materials and Methods: Thirty-four teeth in 17 patients with Miller Class 1 and 2 recession were treated with SCTG with (test group) or without (control group) the application of Nd:YAG laser (1 W, 10 Hz, 100 mj, 60 s, 1064 nm). Clinical attachment level (CAL), recession depth (RD), recession width (RW), and probing depth (PD) were measured at baseline and six months postsurgery. Results: Both treatments yielded significant improvements in terms of RD and RW decrease and CAL gain compared to baseline values. For test and control groups, the average root coverage was 33% and 77%, respectively (p < 0.05), and the complete root coverage was 18% and 65%, respectively (p < 0.05). The control group showed a greater reduction in RD and RW compared with the test group (p < 0.05). Conclusions: The use of Nd:YAG laser as a root surface biomodifier negatively affected the outcome of root coverage with the SCTG. PMID:19860567

Interaction of Escherichia coli with growing salad spinach plants.

PubMed

Warriner, Keith; Ibrahim, Faozia; Dickinson, Matthew; Wright, Charles; Waites, William M

2003-10-01

In this study, the interaction of a bioluminescence-labeled Escherichia coli strain with growing spinach plants was assessed. Through bioluminescence profiles, the direct visualization of E. coli growing around the roots of developing seedlings was accomplished. Subsequent in situ glucuronidase (GUS) staining of seedlings confirmed that E. coli had become internalized within root tissue and, to a limited extent, within hypocotyls. When inoculated seeds were sown in soil microcosms and cultivated for 42 days, E. coli was recovered from the external surfaces of spinach roots and leaves as well as from surface-sterilized roots. When 20-day-old spinach seedlings (from uninoculated seeds) were transferred to soil inoculated with E. coli, the bacterium became established on the plant surface, but internalization into the inner root tissue was restricted. However, for seedlings transferred to a hydroponic system containing 10(2) or 10(3) CFU of E. coli per ml of the circulating nutrient solution, the bacterium was recovered from surface-sterilized roots, indicating that it had been internalized. Differences between E. coli interactions in the soil and those in the hydroponic system may be attributed to greater accessibility of the roots in the latter model. Alternatively, the presence of a competitive microflora in soil may have restricted root colonization by E. coli. The implications of this study's findings with regard to the microbiological safety of minimally processed vegetables are discussed.

Waterlogging-induced changes in root architecture of germplasm accessions of the tropical forage grass Brachiaria humidicola.

PubMed

Cardoso, Juan Andrés; Jiménez, Juan de la Cruz; Rao, Idupulapati M

2014-04-08

Waterlogging is one of the major factors limiting the productivity of pastures in the humid tropics. Brachiaria humidicola is a forage grass commonly used in zones prone to temporary waterlogging. Brachiaria humidicola accessions adapt to waterlogging by increasing aerenchyma in nodal roots above constitutive levels to improve oxygenation of root tissues. In some accessions, waterlogging reduces the number of lateral roots developed from main root axes. Waterlogging-induced reduction of lateral roots could be of adaptive value as lateral roots consume oxygen supplied from above ground via their parent root. However, a reduction in lateral root development could also be detrimental by decreasing the surface area for nutrient and water absorption. To examine the impact of waterlogging on lateral root development, an outdoor study was conducted to test differences in vertical root distribution (in terms of dry mass and length) and the proportion of lateral roots to the total root system (sum of nodal and lateral roots) down the soil profile under drained or waterlogged soil conditions. Plant material consisted of 12 B. humidicola accessions from the gene bank of the International Center for Tropical Agriculture, Colombia. Rooting depth was restricted by 21 days of waterlogging and confined to the first 30 cm below the soil surface. Although waterlogging reduced the overall proportion of lateral roots, its proportion significantly increased in the top 10 cm of the soil. This suggests that soil flooding increases lateral root proliferation of B. humidicola in the upper soil layers. This may compensate for the reduction of root surface area brought about by the restriction of root growth at depths below 30 cm. Further work is needed to test the relative efficiency of nodal and lateral roots for nutrient and water uptake under waterlogged soil conditions. Published by Oxford University Press on behalf of the Annals of Botany Company.

[Effects of Nd: YAG laser irradiation on the root surfaces and adhesion of Streptococcus mutans].

PubMed

Yuanhong, Li; Zhongcheng, Li; Mengqi, Luo; Daonan, Shen; Shu, Zhang; Shu, Meng

2016-12-01

This study aimed to evaluate the effects of treatment with different powers of Nd: YAG laser irradiation on root surfaces and Streptococcus mutans (S. mutans) adhesion. Extracted teeth because of severe periodontal disease were divided into the following four groups: control group, laser group 1, laser group 2, and laser group 3. After scaling and root planning, laser group 1, laser group 2, and laser group 3 were separately treated with Nd: YAG laser irradiation (4/6/8 W, 60 s); however, the control group did not receive the treatment. Scanning electron microscopy (SEM) was used to determine the morphology. S. mutans were cultured with root slices from each group. Colony forming unit per mL (CFU·mL⁻¹) was used to count and compare the amounts of bacteria adhesion among groups. SEM was used to observe the difference of bacteria adhesion to root surfaces between control group (scaling) and laser group 2 (6 W, 60 s), thereby indicating the different bacteria adhesions because of different treatments. Morphology alterations indicated that root surfaces in control group contain obvious smear layer, debris, and biofilm; whereas the root surfaces in laser group contain more cracks with less smear layer and debris. The bacteria counting indicated that S. mutans adhesion to laser group was weaker than that of control group (P<0.05). No statistical significance among the laser groups (P>0.05) was observed. Morphology alterations also verified that S. mutans adhesion to laser group 2 (6 W, 60 s) was weaker than that of control group (scaling). This study demonstrated that Nd: YAG laser irradiation treatment after scaling can reduce smear layer, debris, and biofilm on the root surfaces as compared with conventional scaling. The laser treatment reduces the adhesion of S. mutans as well. However, Nd: YAG laser irradiation can cause cracks on the root surfaces. In this experiment, the optimum laser power of 6 W can thoroughly remove the smear layer and debris, as well as relatively improve the control of thermal damagee.

GENETIC ANALYSIS OF THE AGGA LOCUS INVOLVED IN AGGLUTINATION ND ADHERENCE OF PSEUDOMONAS PUTIDA, A BENEFICIAL FLUORESCENT PSEUDOMONAD

EPA Science Inventory

An isolate of Pseudomonas putida, which rapidly adheres to plant roots is agglutinated by a glycoprotein from root surfaces. gglutination is presented and adherence to the root surface is diminished by Tn5 insertion in mutant 5123. wo cosmid clones from wild type P putida and 2.7...

Quantitative Classification of Rice (Oryza sativa L.) Root Length and Diameter Using Image Analysis.

PubMed

Gu, Dongxiang; Zhen, Fengxian; Hannaway, David B; Zhu, Yan; Liu, Leilei; Cao, Weixing; Tang, Liang

2017-01-01

Quantitative study of root morphological characteristics of plants is helpful for understanding the relationships between their morphology and function. However, few studies and little detailed and accurate information of root characteristics were reported in fine-rooted plants like rice (Oryza sativa L.). The aims of this study were to quantitatively classify fine lateral roots (FLRs), thick lateral roots (TLRs), and nodal roots (NRs) and analyze their dynamics of mean diameter (MD), lengths and surface area percentage with growth stages in rice plant. Pot experiments were carried out during three years with three rice cultivars, three nitrogen (N) rates and three water regimes. In cultivar experiment, among the three cultivars, root length of 'Yangdao 6' was longest, while the MD of its FLR was the smallest, and the mean diameters for TLR and NR were the largest, the surface area percentage (SAP) of TLRs (SAPT) was the highest, indicating that Yangdao 6 has better nitrogen and water uptake ability. High N rate increased the length of different types of roots and increased the MD of lateral roots, decreased the SAP of FLRs (SAPF) and TLRs, but increased the SAP of NRs (SAPN). Moderate decrease of water supply increased root length and diameter, water stress increased the SAPF and SAPT, but decreased SAPN. The quantitative results indicate that rice plant tends to increase lateral roots to get more surface area for nitrogen and water uptake when available assimilates are limiting under nitrogen and water stress environments.

Quantitative Classification of Rice (Oryza sativa L.) Root Length and Diameter Using Image Analysis

PubMed Central

Gu, Dongxiang; Zhen, Fengxian; Hannaway, David B.; Zhu, Yan; Liu, Leilei; Cao, Weixing; Tang, Liang

2017-01-01

Quantitative study of root morphological characteristics of plants is helpful for understanding the relationships between their morphology and function. However, few studies and little detailed and accurate information of root characteristics were reported in fine-rooted plants like rice (Oryza sativa L.). The aims of this study were to quantitatively classify fine lateral roots (FLRs), thick lateral roots (TLRs), and nodal roots (NRs) and analyze their dynamics of mean diameter (MD), lengths and surface area percentage with growth stages in rice plant. Pot experiments were carried out during three years with three rice cultivars, three nitrogen (N) rates and three water regimes. In cultivar experiment, among the three cultivars, root length of ‘Yangdao 6’ was longest, while the MD of its FLR was the smallest, and the mean diameters for TLR and NR were the largest, the surface area percentage (SAP) of TLRs (SAPT) was the highest, indicating that Yangdao 6 has better nitrogen and water uptake ability. High N rate increased the length of different types of roots and increased the MD of lateral roots, decreased the SAP of FLRs (SAPF) and TLRs, but increased the SAP of NRs (SAPN). Moderate decrease of water supply increased root length and diameter, water stress increased the SAPF and SAPT, but decreased SAPN. The quantitative results indicate that rice plant tends to increase lateral roots to get more surface area for nitrogen and water uptake when available assimilates are limiting under nitrogen and water stress environments. PMID:28103264

Semi-Preparative Separation of 10 Caffeoylquinic Acid Derivatives Using High Speed Counter-Current Chromatogaphy Combined with Semi-Preparative HPLC from the Roots of Burdock (Arctium lappa L.).

PubMed

Zheng, Zhenjia; Wang, Xiao; Liu, Pengli; Li, Meng; Dong, Hongjing; Qiao, Xuguang

2018-02-15

Burdock roots are healthy dietary supplements and a kind of famous traditional Chinese medicine, which contains large amounts of caffeoylquinic acid derivatives. However, little research has been reported on the preparative separation of these compounds from burdock roots. In the present study, a combinative method of HSCCC and semi-preparative HPLC was developed for the semi-preparative separation of caffeoylquinic acid derivatives from the burdock roots. The ethyl acetate extract of burdock roots was first fractionated by MCI macroporous resin chromatography and give three fractions (Fr. 1-3) from the elution of 40% methanol. Then, these three fractions (120 mg) were separately subjected to HSCCC for purification with the solvent system composed of petroleum ether-ethyl acetate-methanol-water at different volume ratios, and the mixtures were further purified by semi-preparative HPLC. As a result, a total of eight known caffeoylquinic acid derivatives including 3- O -caffeoylquinic acid (32.7 mg, 95.7%), 1,5- O - dicaffeoylquinic acid (4.3 mg, 97.2%), 3- O -caffeoylquinic acid methyl ester (12.1 mg, 93.2%), 1,3- O -dicaffeoylquinic acid (42.9 mg, 91.1%), 1,5- O -dicaffeoyl-3- O -(4-maloyl)-quinic acid (4.3 mg, 84.5%), 4,5- O -dicaffeoylquinic acid (5.3 mg, 95.5%), 1,5- O -dicaffeoyl-3- O -succinylquinic acid (8.7 mg, 93.4%), and 1,5- O -dicaffeoyl-4- O -succinylquinic acid (1.7 mg, 91.8%), and two new compounds were obtained. The new compounds were 1,4- O -dicaffeoyl-3-succinyl methyl ester quinic acid (14.6 mg, 96.1%) and 1,5- O -dicaffeoyl-3- O -succinyl methyl ester quinic acid (3.1 mg, 92.6%), respectively. The research indicated that the combination of HSCCC and semi-preparative HPLC is a highly efficient approach for preparative separation of the instability and bioactive caffeoylquinic acid derivatives from natural products.

Temperature drives global patterns in forest biomass distribution in leaves, stems, and roots.

PubMed

Reich, Peter B; Luo, Yunjian; Bradford, John B; Poorter, Hendrik; Perry, Charles H; Oleksyn, Jacek

2014-09-23

Whether the fraction of total forest biomass distributed in roots, stems, or leaves varies systematically across geographic gradients remains unknown despite its importance for understanding forest ecology and modeling global carbon cycles. It has been hypothesized that plants should maintain proportionally more biomass in the organ that acquires the most limiting resource. Accordingly, we hypothesize greater biomass distribution in roots and less in stems and foliage in increasingly arid climates and in colder environments at high latitudes. Such a strategy would increase uptake of soil water in dry conditions and of soil nutrients in cold soils, where they are at low supply and are less mobile. We use a large global biomass dataset (>6,200 forests from 61 countries, across a 40 °C gradient in mean annual temperature) to address these questions. Climate metrics involving temperature were better predictors of biomass partitioning than those involving moisture availability, because, surprisingly, fractional distribution of biomass to roots or foliage was unrelated to aridity. In contrast, in increasingly cold climates, the proportion of total forest biomass in roots was greater and in foliage was smaller for both angiosperm and gymnosperm forests. These findings support hypotheses about adaptive strategies of forest trees to temperature and provide biogeographically explicit relationships to improve ecosystem and earth system models. They also will allow, for the first time to our knowledge, representations of root carbon pools that consider biogeographic differences, which are useful for quantifying whole-ecosystem carbon stocks and cycles and for assessing the impact of climate change on forest carbon dynamics.

Temperature drives global patterns in forest biomass distribution in leaves, stems, and roots

PubMed Central

Reich, Peter B.; Luo, Yunjian; Bradford, John B.; Poorter, Hendrik; Perry, Charles H.; Oleksyn, Jacek

2014-01-01

Whether the fraction of total forest biomass distributed in roots, stems, or leaves varies systematically across geographic gradients remains unknown despite its importance for understanding forest ecology and modeling global carbon cycles. It has been hypothesized that plants should maintain proportionally more biomass in the organ that acquires the most limiting resource. Accordingly, we hypothesize greater biomass distribution in roots and less in stems and foliage in increasingly arid climates and in colder environments at high latitudes. Such a strategy would increase uptake of soil water in dry conditions and of soil nutrients in cold soils, where they are at low supply and are less mobile. We use a large global biomass dataset (>6,200 forests from 61 countries, across a 40 °C gradient in mean annual temperature) to address these questions. Climate metrics involving temperature were better predictors of biomass partitioning than those involving moisture availability, because, surprisingly, fractional distribution of biomass to roots or foliage was unrelated to aridity. In contrast, in increasingly cold climates, the proportion of total forest biomass in roots was greater and in foliage was smaller for both angiosperm and gymnosperm forests. These findings support hypotheses about adaptive strategies of forest trees to temperature and provide biogeographically explicit relationships to improve ecosystem and earth system models. They also will allow, for the first time to our knowledge, representations of root carbon pools that consider biogeographic differences, which are useful for quantifying whole-ecosystem carbon stocks and cycles and for assessing the impact of climate change on forest carbon dynamics. PMID:25225412

Temperature drives global patterns in forest biomass distribution in leaves, stems, and roots

USGS Publications Warehouse

Reich, Peter B.; Lou, Yunjian; Bradford, John B.; Poorter, Hendrik; Perry, Charles H.; Oleksyn, Jacek

2014-01-01

Whether the fraction of total forest biomass distributed in roots, stems, or leaves varies systematically across geographic gradients remains unknown despite its importance for understanding forest ecology and modeling global carbon cycles. It has been hypothesized that plants should maintain proportionally more biomass in the organ that acquires the most limiting resource. Accordingly, we hypothesize greater biomass distribution in roots and less in stems and foliage in increasingly arid climates and in colder environments at high latitudes. Such a strategy would increase uptake of soil water in dry conditions and of soil nutrients in cold soils, where they are at low supply and are less mobile. We use a large global biomass dataset (>6,200 forests from 61 countries, across a 40 °C gradient in mean annual temperature) to address these questions. Climate metrics involving temperature were better predictors of biomass partitioning than those involving moisture availability, because, surprisingly, fractional distribution of biomass to roots or foliage was unrelated to aridity. In contrast, in increasingly cold climates, the proportion of total forest biomass in roots was greater and in foliage was smaller for both angiosperm and gymnosperm forests. These findings support hypotheses about adaptive strategies of forest trees to temperature and provide biogeographically explicit relationships to improve ecosystem and earth system models. They also will allow, for the first time to our knowledge, representations of root carbon pools that consider biogeographic differences, which are useful for quantifying whole-ecosystem carbon stocks and cycles and for assessing the impact of climate change on forest carbon dynamics.

A comparison of thermocouple and infrared thermographic analysis of temperature rise on the root surface during the continuous wave of condensation technique.

PubMed

Mc Cullagh, J J; Setchell, D J; Gulabivala, K; Hussey, D L; Biagioni, P; Lamey, P J; Bailey, G

2000-07-01

This study was designed to use two methods of temperature measurement to analyse and quantify the in vitro root surface temperature changes during the initial stage of the continuous wave technique of obturation of 17 single-rooted premolar teeth with standard canal preparations. A model was designed to allow simultaneous temperature measurement with both thermocouples and an infrared thermal imaging system. Two thermocouples were placed on the root surface, one coronally and the other near the root apex. A series of thermal images were recorded by an infrared thermal imaging camera during the downpack procedure. The mean temperature rises on the root surface, as measured by the two thermocouples, averaged 13.9 degrees C over the period of study, whilst the infrared thermal imaging system measured an average rise of 28.4 degrees C at the same sites. Temperatures at the more apical point were higher than those measured coronally. After the first wave of condensation, the second activation of the plugger in the canal prior to its removal always resulted in a secondary rise in temperature. The thermal imaging system detected areas of greater temperature change distant from the two selected thermocouple sites. The continuous wave technique of obturation may result in high temperatures on the external root surface. Infrared thermography is a useful device for mapping patterns of temperature change over a large area.

Application of hydrostatic CCC-TLC-HPLC-ESI-TOF-MS for the bioguided fractionation of anticholinesterase alkaloids from Argemone mexicana L. roots.

PubMed

Kukula-Koch, Wirginia; Mroczek, Tomasz

2015-03-01

A rapid hydrostatic counter-current chromatography-thin-layer chromatography-electrospray-ionization time-of-flight mass spectrometry (CCC-TLC-ESI-TOF-MS) technique was established for use in seeking potent anti-Alzheimer's drugs among the acethylcholinesterase inhibitors in Argemone mexicana L. underground parts, with no need to isolate components in pure form. The dichloromethane extract from the roots of Mexican prickly poppy that was most rich in secondary metabolites was subjected to hydrostatic-CCC-based fractionation in descending mode, using a biphasic system composed of petroleum ether-ethyl acetate-methanol-water at the ratio of 1.5:3:2.1:2 (v/v). The obtained fractions were analyzed in a TLC-based AChE-inhibition "Fast Blue B" test. All active components in the fractions, including berberine, protopine, chelerithrine, sanguinarine, coptisine, palmatine, magnoflorine, and galanthamine, were identified in a direct TLC-HPLC-ESI-TOF-MS assay with high accuracy. This is the first time galanthamine has been reported in the extract of Mexican prickly poppy and the first time it has been identified in any member of the Papaveraceae family, in the significant quantity of 0.77%.

Surface roughness and bacterial adhesion on root dentin treated with diode laser and conventional desensitizing agents.

PubMed

Cury, Maiza S; Silva, Camilla B; Nogueira, Ruchele D; Campos, Michelle G D; Palma-Dibb, Regina G; Geraldo-Martins, Vinicius R

2018-02-01

The treatments for dentin hypersensitivity (DH) may change the surface roughness of the root dentin, which can lead to biofilm accumulation, increasing the risk of root caries. The aim was to compare the surface roughness of root dentin after different treatments of DH and the biofilm formation on those surfaces. After initial surface roughness (Sa) assessment, 50 bovine root fragments received the following treatments (n = 10): G 1-no treatment; G2-5% sodium fluoride varnish; G3-professional application of a desensitizing dentifrice; G4-toothbrushing with a desensitizing dentifrice; and G5-diode laser application (908 nm; 1.5 W, 20 s). The Sa was reevaluated after treatments. Afterward, all samples were incubated in a suspension of Streptococcus mutans at 37 °C for 24 h. The colony-forming units (CFU) were counted using a stereoscope, and the results were expressed in CFU/mL. The one-way ANOVA and the Tukey's tests compared the roughness data and the results obtained on the bacterial adhesion test (α = 5%). G2 (2.3 ± 1.67%) showed similar Sa variation than G1 (0.25 ± 0.41%) and G5 (5.69 ± 0.99%), but different from group G3 (9.05 ± 2.39%). Group 4 showed the highest Sa variation (30.02 ± 3.83%; p < 0.05). Bacterial adhesion was higher in G4 (2208 ± 211.9), suggesting that bacterial growth is greater on rougher surfaces. The diode laser and the conventional treatments for DH may change the surface roughness of the root dentin, but only brushing with desensitizing dentifrice induced a higher bacteria accumulation on root dentin surface.

Identifying the Active Microbiome Associated with Roots and Rhizosphere Soil of Oilseed Rape

PubMed Central

Mahmood, Shahid; Ekblad, Alf; Alström, Sadhna; Högberg, Nils; Finlay, Roger

2017-01-01

ABSTRACT RNA stable isotope probing and high-throughput sequencing were used to characterize the active microbiomes of bacteria and fungi colonizing the roots and rhizosphere soil of oilseed rape to identify taxa assimilating plant-derived carbon following 13CO2 labeling. Root- and rhizosphere soil-associated communities of both bacteria and fungi differed from each other, and there were highly significant differences between their DNA- and RNA-based community profiles. Verrucomicrobia, Proteobacteria, Planctomycetes, Acidobacteria, Gemmatimonadetes, Actinobacteria, and Chloroflexi were the most active bacterial phyla in the rhizosphere soil. Bacteroidetes were more active in roots. The most abundant bacterial genera were well represented in both the 13C- and 12C-RNA fractions, while the fungal taxa were more differentiated. Streptomyces, Rhizobium, and Flavobacterium were dominant in roots, whereas Rhodoplanes and Sphingomonas (Kaistobacter) were dominant in rhizosphere soil. “Candidatus Nitrososphaera” was enriched in 13C in rhizosphere soil. Olpidium and Dendryphion were abundant in the 12C-RNA fraction of roots; Clonostachys was abundant in both roots and rhizosphere soil and heavily 13C enriched. Cryptococcus was dominant in rhizosphere soil and less abundant, but was 13C enriched in roots. The patterns of colonization and C acquisition revealed in this study assist in identifying microbial taxa that may be superior competitors for plant-derived carbon in the rhizosphere of Brassica napus. IMPORTANCE This microbiome study characterizes the active bacteria and fungi colonizing the roots and rhizosphere soil of Brassica napus using high-throughput sequencing and RNA-stable isotope probing. It identifies taxa assimilating plant-derived carbon following 13CO2 labeling and compares these with other less active groups not incorporating a plant assimilate. Brassica napus is an economically and globally important oilseed crop, cultivated for edible oil, biofuel production, and phytoextraction of heavy metals; however, it is susceptible to several diseases. The identification of the fungal and bacterial species successfully competing for plant-derived carbon, enabling them to colonize the roots and rhizosphere soil of this plant, should enable the identification of microorganisms that can be evaluated in more detailed functional studies and ultimately be used to improve plant health and productivity in sustainable agriculture. PMID:28887416

Identifying the Active Microbiome Associated with Roots and Rhizosphere Soil of Oilseed Rape.

PubMed

Gkarmiri, Konstantia; Mahmood, Shahid; Ekblad, Alf; Alström, Sadhna; Högberg, Nils; Finlay, Roger

2017-11-15

RNA stable isotope probing and high-throughput sequencing were used to characterize the active microbiomes of bacteria and fungi colonizing the roots and rhizosphere soil of oilseed rape to identify taxa assimilating plant-derived carbon following 13 CO 2 labeling. Root- and rhizosphere soil-associated communities of both bacteria and fungi differed from each other, and there were highly significant differences between their DNA- and RNA-based community profiles. Verrucomicrobia , Proteobacteria , Planctomycetes , Acidobacteria , Gemmatimonadetes , Actinobacteria , and Chloroflexi were the most active bacterial phyla in the rhizosphere soil. Bacteroidetes were more active in roots. The most abundant bacterial genera were well represented in both the 13 C- and 12 C-RNA fractions, while the fungal taxa were more differentiated. Streptomyces , Rhizobium , and Flavobacterium were dominant in roots, whereas Rhodoplanes and Sphingomonas ( Kaistobacter ) were dominant in rhizosphere soil. " Candidatus Nitrososphaera" was enriched in 13 C in rhizosphere soil. Olpidium and Dendryphion were abundant in the 12 C-RNA fraction of roots; Clonostachys was abundant in both roots and rhizosphere soil and heavily 13 C enriched. Cryptococcus was dominant in rhizosphere soil and less abundant, but was 13 C enriched in roots. The patterns of colonization and C acquisition revealed in this study assist in identifying microbial taxa that may be superior competitors for plant-derived carbon in the rhizosphere of Brassica napus IMPORTANCE This microbiome study characterizes the active bacteria and fungi colonizing the roots and rhizosphere soil of Brassica napus using high-throughput sequencing and RNA-stable isotope probing. It identifies taxa assimilating plant-derived carbon following 13 CO 2 labeling and compares these with other less active groups not incorporating a plant assimilate. Brassica napus is an economically and globally important oilseed crop, cultivated for edible oil, biofuel production, and phytoextraction of heavy metals; however, it is susceptible to several diseases. The identification of the fungal and bacterial species successfully competing for plant-derived carbon, enabling them to colonize the roots and rhizosphere soil of this plant, should enable the identification of microorganisms that can be evaluated in more detailed functional studies and ultimately be used to improve plant health and productivity in sustainable agriculture. Copyright © 2017 American Society for Microbiology.

Land-atmosphere coupling and climate prediction over the U.S. Southern Great Plains

NASA Astrophysics Data System (ADS)

Williams, I. N.; Lu, Y.; Kueppers, L. M.; Riley, W. J.; Biraud, S.; Bagley, J. E.; Torn, M. S.

2016-12-01

Biases in land-atmosphere coupling in climate models can contribute to climate prediction biases, but land models are rarely evaluated in the context of this coupling. We tested land-atmosphere coupling and explored effects of land surface parameterizations on climate prediction in a single-column version of the NCAR Community Earth System Model (CESM1.2.2) and an offline Community Land Model (CLM4.5). The correlation between leaf area index (LAI) and surface evaporative fraction (ratio of latent to total turbulent heat flux) was substantially underpredicted compared to observations in the U.S. Southern Great Plains, while the correlation between soil moisture and evaporative fraction was overpredicted by CLM4.5. These correlations were improved by prescribing observed LAI, increasing soil resistance to evaporation, increasing minimum stomatal conductance, and increasing leaf reflectance. The modifications reduced the root mean squared error (RMSE) in daytime 2 m air temperature from 3.6 C to 2 C in summer (JJA), and reduced RMSE in total JJA precipitation from 133 to 84 mm. The modifications had the largest effect on prediction of summer drought in 2006, when a warm bias in daytime 2 m air temperature was reduced from +6 C to a smaller cold bias of -1.3 C, and a corresponding dry bias in total JJA precipitation was reduced from -111 mm to -23 mm. Thus, the role of vegetation in droughts and heat waves is likely underpredicted in CESM1.2.2, and improvements in land surface models can improve prediction of climate extremes.

[Concentrations and Component Profiles PAHs in Surface Soils and Wheat Grains from the Cornfields Close to the Steel Smelting Industry in Handan, Hebei Province].

PubMed

Wu, Di; Wang, Yi-long; Liu, Wei-jian; Chen, Yuan-chen; Fu, Xiao-fang; Tao, Shu; Liu, Wen-xin

2016-02-15

In this study, paired surface soil and mature wheat grain samples were collected in the cornfields near the large Handan Steel Manufacturer; and the total concentrations and compositional profiles of the parent PAHs were measured, then the spatial distribution characteristics and correlation with total organic carbon fractions in soil were determined. Accordingly, a preliminary source identification was performed, and the association between PAHs in surface soil and wheat grain was briefly discussed. The median concentration of total PAHs in surface soils from the cornfields of Handan was 398.9 ng x g(-1) (ranged from 123.4 ng x g(-1) to 1626.4 ng x g(-1), where around 18% and 10% of all the studied soil samples were over the corresponding quality criteria for total PAHs and B [a] P in soils, respectively. The MMW and HMW species were the main components in the compositional profiles of surface soils. Based on the specific isomeric ratios of PAHs species, coal/biomass combustion and transportation fuel (tail gas) were the dominant mixed sources for the local PAHs emission. The fractions of surface soil TOC had significant positive correlations with the total PAHs and also with the individual components with different rings. In addition, the median concentration of total PAHs in wheat grains collected in the cornfields near the Handan Steel Manufacture was 27.0 ng x g(-1) (ranged from 19.0-34.0 ng x g(-1)). The levels in wheat grains were not high, and lower than the related hygienic standards of food proposed by EU and China. The LMW and MMW PAHs with 2 to 4 rings occupied a larger proportion, more than 84% of the total PAHs, which was largely different from the component profiles in surface soils. This situation suggested that the local sources of PAHs in wheat grains may originate not only from surface soil via root absorption and internal transportation, but also from ambient air through dry and wet deposition on the leaf surface (stoma).

Weathering and vegetation controls on nickel isotope fractionation in surface ultramafic environments (Albania)

NASA Astrophysics Data System (ADS)

Estrade, Nicolas; Cloquet, Christophe; Echevarria, Guillaume; Sterckeman, Thibault; Deng, Tenghaobo; Tang, YeTao; Morel, Jean-Louis

2015-08-01

The dissolved nickel (Ni) isotopic composition of rivers and oceans presents an apparent paradox. Even though rivers represent a major source of Ni in the oceans, seawater is more enriched in the heavier isotopes than river-water. Additional sources or processes must therefore be invoked to account for the isotopic budget of dissolved Ni in seawater. Weathering of continental rocks is thought to play a major role in determining the magnitude and sign of isotopic fractionation of metals between a rock and the dissolved product. We present a study of Ni isotopes in the rock-soil-plant systems of several ultramafic environments. The results reveal key insights into the magnitude and the control of isotopic fractionation during the weathering of continental ultramafic rocks. This study introduces new constraints on the influence of vegetation during the weathering process, which should be taken into account in interpretations of the variability of Ni isotopes in rivers. The study area is located in a temperate climate zone within the ophiolitic belt area of Albania. The serpentinized peridotites sampled present a narrow range of heavy Ni isotopic compositions (δ60Ni = 0.25 ± 0.16 ‰, 2SD n = 2). At two locations, horizons within two soil profiles affected by different degrees of weathering all presented light isotopic compositions compared to the parent rock (Δ60Nisoil-rock up to - 0.63 ‰). This suggests that the soil pool takes up the light isotopes, while the heavier isotopes remain in the dissolved phase. By combining elemental and mineralogical analyses with the isotope compositions determined for the soils, the extent of fractionation was found to be controlled by the secondary minerals formed in the soil. The types of vegetation growing on ultramafic-derived soils are highly adapted and include both Ni-hyperaccumulating species, which can accumulate several percent per weight of Ni, and non-accumulating species. Whole-plant isotopic compositions were found to be isotopically heavier than the soil (Δ60Niwhole plant-soil up to 0.40‰). Fractions of Ni extracted by DTPA (diethylenetriaminepentaacetic acid) presented isotopically heavy compositions compared to the soil (Δ60NiDTPA-soil up to 0.89‰), supporting the hypothesis that the dissolved Ni fraction controlled by weathering has a heavy isotope signature. The non-hyperaccumulators (n = 2) were inclined to take up and translocate light Ni isotopes with a large degree of fractionation (Δ60Nileaves-roots up to - 0.60 ‰). For Ni-hyperaccumulators (n = 7), significant isotopic fractionation was observed in the plants in their early growth stages, while no fractionation occurred during later growth stages, when plants are fully loaded with Ni. This suggests that (i) the high-efficiency translocation process involved in hyperaccumulators does not fractionate Ni isotopes, and (ii) the root uptake process mainly controls the isotopic composition of the plant. In ultramafic contexts, vegetation composed of hyperaccumulators can significantly influence isotopic compositions through its remobilization in the upper soil horizon, thereby influencing the isotopic balance of Ni exported to rivers.

Effect of Er:YAG laser-activated irrigation solution on Enterococcus Faecalis biofilm in an ex-vivo root canal model.

PubMed

Sahar-Helft, Sharonit; Stabholtz, Adam; Moshonov, Joshua; Gutkin, Vitaly; Redenski, Idan; Steinberg, Doron

2013-07-01

Abstract Objective: The purpose of this study was to evaluate mineral content and surface morphology of root canals coated with Enterococcus faecalis biofilm after treatment with several endodontic irrigation solutions, with and without Er:YAG laser-activated irrigation (LAI). LAI has been introduced as a powerful method for root canal irrigation resulting in smear-layer removal from the root canal wall. Distal and palatal roots from 60 freshly extracted human molars were used in this study. The coronal of each tooth was removed. Roots were split longitudinally and placed in an ultrasonic bath to remove the smear layer, creating conditions for the formation of E. faecalis biofilm. After incubation, the two halves were reassembled in impression material to simulate clinical conditions. Specimens were divided into two main groups: roots rinsed with irrigation solutions and roots subjected to laser irradiation combined with irrigation solutions. Solutions tested were 2% chlorhexidine and 17% ethylenediaminetetraacetic acid (EDTA) and saline. Surface morphology: 17% EDTA irrigant solution combined with Er:YAG laser showed the best results for removing bacteria from the root canal walls. Chemical analysis: all samples treated with combined laser irradiation and irrigation solution had low surface levels of Ca compared with samples treated with irrigation alone. The Ca/P ratio was highest in the laser-EDTA group. Overall, mineral changes caused by laser with irrigation solutions were minimal, and statistically nonsignificant. In vitro irrigation solutions, combined with Er:YAG laser irradiation, were effective in removing E. faecalis biofilm from root canal walls. Irrigation solutions without laser irradiation were less effective, leaving a layer of biofilm on the dentin surface.

Canal Transportation, Unprepared Areas, and Dentin Removal after Preparation with BT-RaCe and ProTaper Next Systems.

PubMed

Brasil, Sabrina C; Marceliano-Alves, Marília F; Marques, Márcia L; Grillo, João P; Lacerda, Mariane F L S; Alves, Flávio R F; Siqueira, José F; Provenzano, José C

2017-10-01

This study compared the shaping ability of ProTaper Next (Dentsply Sirona, Tulsa, OK) and BT-RaCe (FKG Dentaire, La Chaux-de-Fonds, Switzerland) instrument systems in the mesial canals of mandibular molars using micro-computed tomographic (micro-CT) imaging. A total of 17 type IV mesial roots of extracted first mandibular molars were scanned using micro-CT imaging before and after root canal preparation with the 2 instrument systems. Both systems were used in the same root but alternating the mesial canals from root to root. The following parameters were analyzed: root canal volume, surface area, unprepared surface areas, transportation, canal/root width ratio, and preparation time. There were no statistically significant differences between the 2 systems for all evaluated parameters (P > .05). The unprepared surface areas for the full canal length and the apical 5-mm segment were 33% and 14% for BT-RaCe and 31% and 14% for ProTaper Next, respectively. After preparation, all root canals had a diameter that was not larger than 35% of the root diameter at the coronal and middle segments. The 2 systems showed no differences in any of the evaluated shaping parameters. None of the tested systems put the roots at risk of fracture because of excessive dentin removal. Copyright © 2017 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Scanning electron microscopic study of the effects of Er:YAG laser on root cementum.

PubMed

Fujii, T; Baehni, P C; Kawai, O; Kawakami, T; Matsuda, K; Kowashi, Y

1998-11-01

Use of Er:YAG laser has been proposed for the removal of microbial deposits and calculus present on teeth affected by periodontal disease. However, the influence of Er:YAG laser irradiation on root surfaces has not yet been fully investigated. The aim of the present study was to evaluate the effects of Er:YAG laser irradiation on root cementum by scanning electron microscopy (SEM). Specimens were obtained from extracted human periodontally-diseased teeth using a water-cooled high-speed bur. An Er:YAG laser beam was then applied at various powers ranging from 25 to 100 mJ/ pulse/sec. The laser irradiation was performed under water irrigation, with the tip held perpendicular to the root surface in the contact mode. Following laser exposure, specimens were fixed, dehydrated, and dried at critical-point in liquid CO2. After mounting on SEM plates and sputter-coating with gold, the cementum surface was examined by SEM. Observations of the root surface showed a relatively flat surface in control specimens. In Er:YAG exposed specimens, the laser beam created a circular, notched-edge, crater-like defect on the root. The bottom of the lesion showed an irregular and sharp-pointed surface. Subsequently, the specimens were fractured with a sharp scalpel perpendicularly to the surface. SEM observations of these specimens showed a 15 microm layer of damaged tissue within the laser-irradiated cementum. The tissue presented an amorphous appearance and the Sharpey's and matrix fiber bundles were not clearly distinguishable. These observations indicate that cementum tissue could be damaged by Er:YAG laser irradiation.

Effect of zoledronic acid used in the root surface treatment of late replanted teeth: a study in rats.

PubMed

Mori, Graziela Garrido; Janjacomo, Daniela Maria de Mendonça; Nunes, Daniele Clapes; Castilho, Lithiene Ribeiro

2010-01-01

This study evaluated the use of zoledronic acid, a resorption inhibitor, as a medication for root resorption treatment of late replanted teeth. Twenty-four maxillary right central incisors of rats were avulsed and kept dry for 30 min. Then, the teeth were divided into 2 groups. In group I, root surface was treated with 2% sodium fluoride for 20 min; in group II, 10-6M zoledronic acid solution was used for 20 min. All root canals were filled with calcium hydroxide. Next, teeth were replanted in their respective sockets. After 15 and 60 days post-replantation, the animals were killed and the anatomic pieces were obtained and prepared for microscopic and morphometric analyses. The results showed that zoledronic acid was capable of limiting the occurrence of root resorption and preserving cementum resorption. Further research must be performed to confirm the use of zoledronic acid in root surface treatment of late replanted teeth.

BIOLOGICAL AND PHYTOCHEMICAL INVESTIGATIONS OF EXTRACTS FROM PTEROCARPUS ERINACEUS POIR (FABACEAE) ROOT BARKS

PubMed Central

Noufou, Ouédraogo; Anne-Emmanuelle, Hay; Claude W, Ouédraogo Jean; Richard, Sawadogo W; André, Tibiri; Marius, Lompo; Jean-baptiste, Nikiema; Jean, Koudou; Marie-Genevieve, Dijoux-Franca; Pierre, Guissou Innocent

2017-01-01

Background: Pterocarpus erinaceus Poir. belonging to Fabacae familly is used as medicinal plant in Burkina Faso’s folk medicine. Roots of P. erinaceus are used to treat ulcer, stomach ache and inflammatory diseases. The objective of the present study was to carry out phytochemical composition of methanol (MeOH) and dichloromethane (DCM) extracts from Pterocarpus erinaceus roots, to isolate pure compounds, and to evaluate their pharmacological activities. Methods: Chromatographic fractionation led to the isolation of active components of the extracts. The structures were established by NMR analysis and comparison with data from literature. The anti-inflammatory activity was evaluated using croton oil-induced edema of mice ear as well as the effect of extracts against lipoxygenase and lipid peroxidation was evaluated. 2,2-diphenyl-1-picrylhydrazyl (DPPH) and Cupric-reducing antioxidant capacity (CUPRAC) methods were used to evaluate the antioxidant activity of the extracts. Results: Friedelin (1), 3a-hydroxyfriedelan-2-one (2), a-sophoradiol (3) and stigmasterol (4) were isolated from DCM extract and maltol-6-O-apiofuranoside-glucopyranoside (5) isolated from MeOH. DCM extract and friedelin, 3a-hydroxyfriedelan-2-one, a-sophoradiol showed a significant anti-inflammatory effect against ear edema. Friedelin (1), α-sophoradiol (3) and maltol-6-O-apiofuranoside-glucopyranoside (5) exhibited lipoxygenase inhibition. MeOH extract (100 μg/mL) inhibited lipoxygenase and lipid peroxidation activities at 45.1 ± 3% and 30.7 ± 0.5% respectively. MeOH extract, ethyl acetate fraction and butanol fraction exhibited antioxidant property with both two methods used. Conclusion: The results suggested that the extracts and compounds from roots of Pterocarpus erinaceus possessed local anti-inflammatory effect, antioxidant properties and inhibitor effect against lipoxygenase and lipid peroxidation activities. PMID:28480397

Cross-reactive antigens and lectin as determinants of symbiotic specificity in the Rhizobium-clover association.

PubMed Central

Dazzo, F B; Hubbell, D H

1975-01-01

Cross-reactive antigens of clover roots and Rhizobium trifolii were detected on their cell surfaces by tube agglutination, immunofluorescent, and radioimmunoassay techniques. Anti-clover root antiserum had a higher agglutinating titer with infective strains of R. trifolii than with noninfective strains. The root antiserum previously adsorbed with noninfective R. trifolii cells remained reactive only with infective cells, including infective revertants. When adsorbed with infective cells, the root antiserum was reactive with neither infective nor noninfective cells. Other Rhizobium species incapable of infecting clover did not demonstrate surface antigens cross-reactive with clover. Radioimmunoassay indicated twice as much antigenic cross-reactivity of clover roots and R. trifolii 403 (infective) than R. trifolii Bart A (noninfective). Immunofluorescence with anti-R. trifolii (infective) antiserum was detected on the exposed surface of the root epidermal cells and diminished at the root meristem. The immunofluorescent crossreaction on clover roots was totally removed by adsorption of anti-R. trifolii (infective) antiserum with encapsulated infective cells but not with noninfective cells. The cross-reactive capsular antigens from R. trifolii strains were extracted and purified. The ability of these antigens to induce clover root hair deformation was much greater when they were obtained from the infective than noninfective strains. The cross-reactive capsular antigen of R. trifolii 403 was characterized as a high-molecular-weight (greater than 4.6 times 10(6) daltons), beta-linked, acidic heteropolysaccharide containing 2-deoxyglucose, galactose, glucose, and glucuronic acid. A soluble, nondialyzable, substance (clover lectin) capable of binding to the cross-reactive antigen and agglutinating only infective cells of R. trifolii was extracted from white clover seeds. This lectin was sensitive to heat, Pronase, and trypsin. inhibition studies indicated that 2-deoxyglucose was the most probable haptenic determinant of the cross-reactive capsular antigen capable of binding to the root antiserum and the clover lectin. A model is proposed suggesting the preferential adsorption of infective versus noninfective cells of R. trifolii on the surface of clover roots by a cross-bridging of their common surface antigens with a multivalent clover lectin. Images PMID:55100

Evaluation of Temperature Elevation During Root Canal Treatment with Dual Wavelength Laser: 2780 nm Er,Cr:YSGG and 940 nm Diode.

PubMed

Al-Karadaghi, Tamara Sardar; Gutknecht, Norbert; Jawad, Hussein A; Vanweersch, Leon; Franzen, Rene

2015-09-01

The purpose of this study was to evaluate the effects of dual wavelength (2780 nm Er,Cr:YSGG and 940 nm diode) laser with radial firing tip (RFT) on the external root surface and sub-surfaces, in terms of temperature changes during laser-assisted root canal treatment. A significant factor that may limit the use of lasers in endodontics is the possible thermal injury to tooth supporting structures. A total of 50 sound single-rooted extracted teeth were divided randomly into two groups (n = 25). Group A, irradiated with Er,Cr:YSGG laser at 1.06 W, 50 Hz, and 50 μs was a control group, and group B was irradiated with dual wavelength of Er,Cr:YSGG laser with the same settings as group A and a diode laser of 0.51 W at 4 ms and 10 ms pulse duration. K-type thermocouples were used to record temperature changes at the cervical, middle, and apical root thirds, on root surfaces and sub-surfaces, arising from delivery of laser energy through RFT. Temperature elevation in group B was significantly higher in the middle and apical thirds of the prepared samples than in group A (p < 0.0001). Group B presented a mean temperature elevation of 5.07°C on the apical surface region corresponding to a 1.48 mm dentin thickness, whereas a mean temperature increase of 7.72°C was recorded corresponding to dentin thickness of 0.95 mm. Within the studied parameters, the dual wavelength laser did not result in adverse thermal changes on the external root surface in vitro.

Root surface temperature variation during mechanical removal of root canal filling material. An in vitro study.

PubMed

García-Cuerva, Martín; Horvath, Lucía; Pinasco, Laura; Ciparelli, Verónica; Gualtieri, Ariel; Casadoumecq, Ana C; Rodríguez, Pablo; Gonzalez-Zanotto, Carlos

2017-04-01

The aim of this study was to analyze in vitro temperature changes on the outer surface of the dental root during mechanical filling removal procedures. Thirty recently extracted single-rooted lower premolars were cut transversally at 16 mm from the apex in order to standardize sample length. Endodontic treatment was performed on them. The filling material was subsequently removed using Gates Glidden (G1, G2, G3); Peeso (P1, P2, P3) and PostecPlus FRC (FRC) reamers while temperatures were measured on the outer surface using a digital device with thermocouple at 0, 2, 4, 6, 8, 10 and 15 seconds. Temperatures were compared using repeated measures ANOVA followed by pairwise comparison with Tukey's test. All reamers caused significant temperature variation between different times (p<0.05). Pairwise comparisons indicated that temperature increased with time for all reamers (p<0.05). Significant differences in temperature were found between different reamers after 0, 2, 4, 6, 8,10 and 15 seconds (p<0.05). Temperature at the root surface increased considerably. Values higher than 50°C were recorded, the greatest increase from baseline being 16°C. Accordingly, if the procedure were begun at 37°C (physiological temperature), the temperature in the surrounding tissues - cementum, periodontium and bone - would rise to 53°C. An increase in 10°C above body temperature at the root surface may cause lesions in surrounding tissues. While removing filling material, it is essential to cool, control action time and use instruments in perfect condition, all of which may contribute to reducing the heat generated and transmitted to the outer root surface. Sociedad Argentina de Pediatría.

Influence of elevated carbon dioxide and temperature on belowground carbon allocation and enzyme activities in tropical flooded soil planted with rice.

PubMed

Bhattacharyya, P; Roy, K S; Neogi, S; Manna, M C; Adhya, T K; Rao, K S; Nayak, A K

2013-10-01

Changes in the soil labile carbon fractions and soil biochemical properties to elevated carbon dioxide (CO2) and temperature reflect the changes in the functional capacity of soil ecosystems. The belowground root system and root-derived carbon products are the key factors for the rhizospheric carbon dynamics under elevated CO2 condition. However, the relationship between interactive effects of elevated CO2 and temperature on belowground soil carbon accrual is not very clear. To address this issue, a field experiment was laid out to study the changes of carbon allocation in tropical rice soil (Aeric Endoaquept) under elevated CO2 and elevated CO2 + elevated temperature conditions in open top chambers (OTCs). There were significant increase of root biomass by 39 and 44 % under elevated CO2 and elevated CO2 + temperature compared to ambient condition, respectively. A significant increase (55 %) of total organic carbon in the root exudates under elevated CO2 + temperature was noticed. Carbon dioxide enrichment associated with elevated temperature significantly increased soil labile carbon, microbial biomass carbon, and activities of carbon-transforming enzyme like β-glucosidase. Highly significant correlations were noticed among the different soil enzymes and soil labile carbon fractions.

Effect of odanacatib on root resorption and alveolar bone metabolism during orthodontic tooth movement.

PubMed

Wei, X X; Chu, J P; Zou, Y Z; Ru, N; Cui, S X; Bai, Y X

2015-12-22

The aim of this study was to investigate the effect of local administration of odanacatib (ODN) on orthodontic root resorption and the status of alveolar bone metabolism in rat molars. All specimens were scanned using microcomputed tomography and then the raw images were reconstructed. The total volume of the root resorption craters of the 60 g-NS (normal saline) group was higher than in the 60 g-ODN group and the control group. In the 60 g-NS group, the bone volume fraction values of alveolar bone were significantly decreased compared with the other 2 groups. There were no significant differences in the bone volume fraction values of the tibiae among the 3 groups. The results of tartrate-resistant acid phosphatase-positive (TRAP+) numbers showed that there was no difference between the 60 g-NS group and the 60 g-ODN group. The expression of cathepsin K was decreased significantly in the 60 g-ODN group. These results indicate that ODN reduces orthodontics-induced external root resorption and increases alveolar bone metabolism. This may be because ODN inhibits the activity of odontoclasts, but maintains the quantity of odontoclasts and enhances bone formation. ODN promotes local alveolar bone metabolism, but does not affect systemic bone metabolism.

Impact of adhesive surface and volume of luting resin on fracture resistance of root filled teeth.

PubMed

Krastl, G; Gugger, J; Deyhle, H; Zitzmann, N U; Weiger, R; Müller, B

2011-05-01

To investigate the correlation between geometric parameters of severely compromised root filled (RCT) pre-molar teeth with irregular root canals and their fracture resistance. The null hypothesis tested was that the fracture resistance of root filled teeth is not influenced by: (i) the adhesive surface of the post-space preparation (A(PS) ), (ii) the coronal tooth surface (A(A) ), (iii) the amount of resin cement (V(C) ) and (iv) the Young's modulus of the specimens. A total of 48 noncarious human pre-molar teeth with irregular root canals were decoronated, root filled and adhesively restored with post-retained direct composite crowns. After thermomechanical loading (1,200,000×, 5-50° C), static load was applied until failure. The geometric parameters of the tooth were evaluated by microcomputed tomography (μCT) using impressions taken after post-space preparation. Linear regression analyses were performed to correlate the geometric parameters of the specimens with their fracture resistance. The amount of resin cement (V(C) ) comprised up to 88% of the entire post-space (mean 67%) and had no impact on the maximal load (P = 0.88). The latter was significantly influenced by post-space preparation (P = 0.003). Amongst the geometric parameters tested, the surface area in the root canal had the greatest impact on fracture resistance of root filled pre-molars restored with posts and composite crowns, whilst the fit of the post was less important. © 2011 International Endodontic Journal.

A comparative evaluation of the increase in root canal surface area and canal transportation in curved root canals by three rotary systems: A cone-beam computed tomographic study

PubMed Central

Prasanthi, Nalam NVD; Rambabu, Tanikonda; Sajjan, Girija S; Varma, K Madhu; Satish, R Kalyan; Padmaja, M

2016-01-01

Aim: The aim of this study was to measure the increase in root canal surface area and canal transportation after biomechanical preparation at 1, 3, and 5 mm short of the apex with three different rotary systems in both continuous rotary and reciprocating rotary motions. Materials and Methods: Sixty freshly extracted human mandibular molars with mesial root canal curvatures between 20° and 30° were included in the study. Teeth were randomly distributed into three groups (n = 20). Biomechanical preparations were done in all the mesial canals. In Group 1, instrumentation was done with ProTaper universal rotary files, Group 2, with K3XF rotary files, and Group 3, with LSX rotary files. Each group was further subdivided into subgroups A and B (n = 10) where instrumentation was done by continuous rotary and reciprocating rotary techniques, respectively. Increase in root canal surface area and canal transportation was measured using the preoperative and postoperative cone-beam computed tomography scans. Statistical Analysis: The data were analyzed by one-way ANOVA followed by Tukey pairwise multiple comparison tests. Results: Increase in root canal surface area was significantly more (P < 0.05) in ProTaper and K3XF groups when compared to LSX group. Canal transportation was significantly more (P < 0.05) in ProTaper group when compared to K3XF and LSX groups. There was no significant difference (P > 0.05) in increase of root canal surface area and canal transportation between continuous rotary and reciprocating rotary techniques for ProTaper Universal, K3XF and LSX groups. Conclusion: LSX rotary system showed minimal increase of root canal surface area and minimal canal transportation when compared to ProTaper and K3XF rotary systems. PMID:27656062

The effect of four different irrigation systems in the removal of a root canal sealer.

PubMed

Grischke, J; Müller-Heine, A; Hülsmann, M

2014-09-01

The aim of this study was to compare the efficiency of sonic, ultrasonic, and hydrodynamic devices in the removal of a root canal sealer from the surface and from simulated irregularities of root canals. Fifty-three root canals with two standardized grooves in the apical and coronal parts of longitudinally split roots were covered with AH Plus root canal sealer. Compared were the effects of (control) syringe irrigation, (1) CanalBrush, (2) passive ultrasonic irrigation, (3) EndoActivator, and (4) RinsEndo on the removal of the sealer. The specimens were divided into four groups (N = 12) and one control group (N = 5) via randomization. The amount of remaining sealer in the root canal irregularities was evaluated under a microscope using a 4-grade scoring system, whereas the remaining sealer on the root canal surface was evaluated with a 7-grade scoring system. Passive ultrasonic irrigation is more effective than the other tested irrigation systems or syringe irrigation in removing sealer from root canal walls (p < 0.01). None of the techniques had a significant effect on cleaning the lateral grooves. Within the limitations of this study protocol ultrasonic irrigation shows a superior effect on sealer removal from the root canal surface during endodontic retreatment. Cleaning of lateral grooves seems not to be possible with one of the techniques investigated. Incomplete removal of root canal sealer during re-treatment may cause treatment failure. Passive Ultrasonic irrigation seems to be the most effective system to remove sealer from a root canal.

Cold temperature delays wound healing in postharvest sugarbeet roots

USDA-ARS?s Scientific Manuscript database

Storage temperature affects the rate and extent of wound-healing in a number of root and tuber crops. The effect of storage temperature on wound-healing in sugarbeet (Beta vulgaris L.) roots, however, is largely unknown. Wound-healing of sugarbeet roots was investigated using surface-abraded roots s...

Implementing dynamic root optimization in Noah-MP for simulating phreatophytic root water uptake

USDA-ARS?s Scientific Manuscript database

Plants are known to adjust their root systems to adapt to changing subsurface water conditions. However, most current land surface models (LSMs) use a prescribed, static root profile, which cuts off the interactions between soil moisture and root dynamics. In this paper, we implemented an optimality...

Immunological Evidence for the Existence of a Carrier Protein for Sucrose Transport in Tonoplast Vesicles from Red Beet (Beta vulgaris L.) Root Storage Tissue.

PubMed Central

Getz, H. P.; Grosclaude, J.; Kurkdjian, A.; Lelievre, F.; Maretzki, A.; Guern, J.

1993-01-01

Monoclonal antibodies were raised in mice against a highly purified tonoplast fraction from isolated red beet (Beta vulgaris L. ssp. conditiva) root vacuoles. Positive hybridoma clones and sub-clones were identified by prescreening using an enzyme-linked immunosorbent assay (ELISA) and by postscreening using a functional assay. This functional assay consisted of testing the impact of hybridoma supernatants and antibody-containing ascites fluids on basal and ATP-stimulated sugar uptake in vacuoles, isolated from protoplasts, as well as in tonoplast vesicles, prepared from tissue homogenates of red beet roots. Antibodies from four clones were particularly positive in ELISAs and they inhibited sucrose uptake significantly. These antibodies were specific inhibitors of sucrose transport, but they exhibited relatively low membrane and species specificity since uptake into red beet root protoplasts and sugarcane tonoplast vesicles was inhibited as well. Fast protein liquid chromatography assisted size exclusion chromatography on Superose 6 columns yielded two major peaks in the 55 to 65-kD regions and in the 110- to 130-kD regions of solubilized proteins from red beet root tonoplasts, which reacted positively in immunoglobulin-M(IgM)-specific ELISAs with anti-sugarcane tonoplast monoclonal IgM antibodies. Only reconstituted proteoliposomes containing polypeptides from the 55- to 65-kD band took up [14C]-sucrose with linear rates for 2 min, suggesting that this fraction contains the tonoplast sucrose carrier. PMID:12231863

A comprehensive review on the stinging nettle effect and efficacy profiles. Part II: urticae radix.

PubMed

Chrubasik, Julia E; Roufogalis, Basil D; Wagner, Hildebert; Chrubasik, Sigrun

2007-08-01

Nettle root is recommended for complaints associated with benign prostatic hyperplasia (BPH). We therefore conducted a comprehensive review of the literature to summarise the pharmacological and clinical effects of this plant material. Only a few components of the active principle have been identified and the mechanism of action is still unclear. It seems likely that sex hormone binding globulin (SHBG), aromatase, epidermal growth factor and prostate steroid membrane receptors are involved in the anti-prostatic effect, but less likely that 5alpha-reductase or androgen receptors are involved. Extract and a polysaccharide fraction were shown to exert anti-inflammatory activity. A proprietary methanolic nettle root extract and particular fractions inhibited cell proliferation. Isolated lectins (UDA) were shown to be promising immunomodulatory agents, having also anti-viral and fungistatic effects. However, despite these in vitro studies it is unclear whether the in-vitro or animal data are a surrogate for clinical effects. The clinical evidence of effectiveness for nettle root in the treatment of BPH is based on many open studies. A small number of randomised controlled studies indicate that a proprietary methanolic extract is effective in improving BPH complaints. However, the significance and magnitude of the effect remains to be established in further confirmatory studies before nettle root treatment may be accepted in the guidelines for BPH treatment. The risk for adverse events during nettle root treatment is very low, as is its toxicity. Pre-clinical safety data remain to be completed.

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

Adkins, Jaron; Jastrow, Julie D.; Morris, Geoffrey P.

Switchgrass (Panicum virgatum L), a cellulosic biofuel feedstock, may promote soil C 21 accumulation compared to annual cropping systems by increasing the amount and retention of 22 root-derived soil C inputs. The aim of this study was to assess how different switchgrass 23 cultivars impact soil C inputs and retention, whether these impacts vary with depth, and whether 24 specific root length (SRL) explains these impacts. We collected soil to a depth of 30 cm from six 25 switchgrass cultivars with root systems ranging from high to low SRL. The cultivars (C4 species) 26 were grown for 27 months onmore » soils previously dominated by C3 plants, allowing us to use the 27 natural difference in 13C isotopic signatures between C3 soils and C4 plants to quantify 28 switchgrass-derived C accumulation. The soil was fractionated into coarse particulate organic 29 matter (CPOM), fine particulate organic matter (FPOM), silt, and clay-sized fractions. We 30 measured total C and plant-derived C in all soil fractions across all depths. The study led to two main results: (1) bulk soil C concentrations beneath switchgrass cultivars varied by 40% in the 0-32 10 cm soil depth and by 70% in the 10-20 cm soil depth, and cultivars with high bulk soil C 33 concentrations tended to have relatively high C concentrations in the mineral soil fractions and 34 relatively low C concentrations in the POM fractions; (2) there were significant differences in 35 switchgrass-derived soil C between cultivars at the 0-10 cm depth, where soil C inputs ranged 36 from 1.2 to 3.2 mg C g-1 dry soil. There was also evidence of a positive correlation between SRL 37 and switchgrass-derived C inputs when one outlier data point was removed. These results 38 indicate that switchgrass cultivars differentially impact mechanisms contributing to soil C accumulation.« less

Defensive strategies in Geranium sylvaticum, Part 2: Roles of water-soluble tannins, flavonoids and phenolic acids against natural enemies.

PubMed

Tuominen, Anu

2013-11-01

Geranium sylvaticum is a common herbaceous plant in Fennoscandia, which has a unique phenolic composition. Ellagitannins, proanthocyanidins, galloylglucoses, gallotannins, galloyl quinic acids and flavonoids possess variable distribution in its different organs. These phenolic compounds are thought to have an important role in plant-herbivore interactions. The aim of this study was to quantify these different water-soluble phenolic compounds and measure the biological activity of the eight organs of G. sylvaticum. Compounds were characterized and quantified using HPLC-DAD/MS, in addition, total proanthocyanidins were determined by BuOH-HCl assay and total phenolics by the Folin-Ciocalteau method. Two in vitro biological activity measurements were used: the prooxidant activity was measured by the browning assay and antioxidant activity by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay. Organ extracts were fractionated using column chromatography on Sephadex LH-20 and the activities of fractions was similarly measured to evaluate which polyphenol groups contributed the most to the biological activity of each organ. The data on the activity of fractions were examined by multivariate data analysis. The water-soluble extracts of leaves and pistils, which contained over 30% of the dry weight as ellagitannins, showed the highest pro-oxidant activity among the organ extracts. Fraction analysis revealed that flavonoids and galloyl quinic acids also exhibited high pro-oxidant activity. In contrast, the most antioxidant active organ extracts were those of the main roots and hairy roots that contained high amounts of proanthocyanidins in addition to ellagitannins. Analysis of the fractions showed that especially ellagitannins and galloyl quinic acids have high antioxidant activity. We conclude that G. sylvaticum allocates a significant amount of tannins in those plant parts that are important to the fitness of the plant and susceptible to natural enemies, i.e. pistil and leaf tannins protect against insect herbivores and root tannins against soil pathogens. Copyright © 2013 Elsevier Ltd. All rights reserved.

Structural composition of organic matter in particle-size fractions of soils along a climo-biosequence in the main range of Peninsular Malaysia

NASA Astrophysics Data System (ADS)

Jafarzadeh-Haghighi, Amir Hossein; Shamshuddin, Jusop; Hamdan, Jol; Zainuddin, Norhazlin

2016-09-01

Information on structural composition of organic matter (OM) in particle-size fractions of soils along a climo-biosequence is sparse. The objective of this study was to examine structural composition and morphological characteristics of OM in particle-size fractions of soils along a climo-biosequence in order to better understand the factors and processes affecting structural composition of soil organic matter. To explore changes in structural composition of OM in soils with different pedogenesis, the A-horizon was considered for further analyses including particle-size fractionation, solid-state 13C nuclear magnetic resonance (NMR) spectroscopy and scanning electron microscopy (SEM). Due to the increase in the thickness of organic layer with increasing elevation, the A-horizon was situated at greater depth in soils of higher elevation. The relationship between relative abundances of carbon (C) structures and particle-size fractions was examined using principal component analysis (PCA). It was found that alkyl C (20.1-73.4%) and O-alkyl C (16.8-67.7%) dominated particle-size fractions. The proportion of alkyl C increased with increasing elevation, while O-alkyl C showed an opposite trend. Results of PCA confirmed this finding and showed the relative enrichment of alkyl C in soils of higher elevation. Increase in the proportion of alkyl C in 250-2000 μm fraction is linked to selective preservation of aliphatic compounds derived from root litter. SEM results showed an increase in root contribution to the 250-2000 μm fraction with increasing elevation. For the <53 μm fraction, pedogenic process of podzolization is responsible for the relative enrichment of alkyl C. This study demonstrates that changes in structural composition of OM in particle-size fractions of soils along the studied climo-biosequence are attributed to site-specific differences in pedogenesis as a function of climate and vegetation.

Cholinesterase inhibitors from the roots of Harpagophytum procumbens.

PubMed

Bae, Yoon Ho; Cuong, To Dao; Hung, Tran Manh; Kim, Jeong Ah; Woo, Mi Hee; Byeon, Jeong Su; Choi, Jae Sue; Min, Byung Sun

2014-01-01

Inhibition of cholinesterase has been proposed to be a therapeutic target for the treatment of Alzheimer's diseases. In our preliminary screening study on the acetylcholinesterase (AChE) inhibitory activity, an ethyl acetate soluble fraction of the roots of Harpagophytum procumbens (Pedaliaceae) was found to inhibit AChE activity at the concentration of 100 μg/mL. Ten compounds (1-10) were isolated from the active fraction and evaluated for their inhibitory effect on AChE and butyrylcholinesterase (BChE). Among the isolates, verbascosides (5, 6, and 8) containing a caffeoyl and a 3,4-dihydroxyphenethyl groups in their structures, showed effective AChE inhibitory activity and also possessed BChE inhibitory activity. The findings suggest that verbascoside derivatives may be partially related to the anti-Alzheimer effect of this medicinal plant.

Isoflavanones from the allelopathic aqueous root exudate of Desmodium uncinatum.

PubMed

Tsanuo, Muniru K; Hassanali, Ahmed; Hooper, Antony M; Khan, Zeyaur; Kaberia, Festus; Pickett, John A; Wadhams, Lester J

2003-09-01

Three isoflavanones, 5,7,2',4'-tetrahydroxy-6-(3-methylbut-2-enyl)isoflavanone (1), 4",5"-dihydro-5,2',4'-trihydroxy-5"-isopropenylfurano-(2",3";7,6)-isoflavanone (2) and 4",5"-dihydro-2'-methoxy-5,4'-dihydroxy-5"-isopropenylfurano-(2",3";7,6)-isoflavanone (3) and a previously known isoflavone 5,7,4'-trihydroxyisoflavone [genistein (4)] were isolated and characterised spectroscopically from the root exudate of the legume Desmodium uncinatum (Jacq.) DC. We propose the names uncinanone A, B, and C for compounds 1, 2 and 3, respectively. Isolated fractions containing uncinanone B (2) induced germination of seeds from the parasitic weed Striga hermonthica (Del.) Benth. and fractions containing uncinanone C (3) moderately inhibited radical growth, the first example of a newly identified potential allelopathic mechanism to prevent S. hermonthica parasitism.

[Distortion and vertical fracture of the root: effect produced by condenser design].

PubMed

Dang, D A; Walton, R E

1990-01-01

The incidence of vertical root fractures and the amount of root distortion created during lateral condensation of gutta-percha with either D11 spreaders or B-finger pluggers were evaluated in vitro. Fifty-five extracted human, single-rooted teeth were instrumented using the step-back flare technique. Ten teeth served as positive controls (obturation to the point of fracture) and five teeth as negative controls (prepared but not obtured). Strain gauges were attached to the root surfaces. In the experimental group, 20 teeth were obturated using a D11 spreader and 20 with a B-finger plugger. Recordings were made of root distortion (expansion) created during obturation. Then, after sectioning the teeth, root surfaces of obturated samples were examined for fractures under the scanning electron microscope. Only the more tapered spreader, the D11, produces vertical root fractures, although very few in number. Also, the D11 spreader caused greater root distortion than did the B-finger plugger.

Thermal measurement of root surface temperatures during application of intracanal laser energy in vitro

NASA Astrophysics Data System (ADS)

Goodis, Harold E.; White, Joel M.; Neev, Joseph

1993-07-01

The use of laser energy to clean, shape, and sterilize a root canal system space involves the generation of heat due to the thermal effect of the laser on the organic tissue contents and dentin walls of that space. If heat generation is above physiologic levels, irreparable damage may occur to the periodontal ligament and surrounding bone. This study measured temperature rise on the outer root surfaces of extracted teeth during intracanal laser exposure. Thirty single rooted, recently extracted teeth free of caries and restorations were accessed pulps extirpated and divided into three groups. Each root canal system was treated with a 1.06 micrometers pulsed Nd:YAG laser with quartz contact probes. Temperatures were recorded for all surfaces (mesial distal, buccal, lingual, apical) with infrared thermography utilizing a detector response time of 1 (mu) sec, sensitivity range (infrared) of 8 to 12 micrometers and a scan rate of 30 frames/sec.

Nitrogen metabolism of two contrasting poplar species during acclimation to limiting nitrogen availability

PubMed Central

Luo, Zhi-Bin

2013-01-01

To investigate N metabolism of two contrasting Populus species in acclimation to low N availability, saplings of slow-growing species (Populus popularis, Pp) and a fast-growing species (Populus alba × Populus glandulosa, Pg) were exposed to 10, 100, or 1000 μM NH4NO3. Despite greater root biomass and fine root surface area in Pp, lower net influxes of NH4 + and NO3 – at the root surface were detected in Pp compared to those in Pg, corresponding well to lower NH4 + and NO3 – content and total N concentration in Pp roots. Meanwhile, higher stable N isotope composition (δ15N) in roots and stronger responsiveness of transcriptional regulation of 18 genes involved in N metabolism were found in roots and leaves of Pp compared to those of Pg. These results indicate that the N metabolism of Pp is more sensitive to decreasing N availability than that of Pg. In both species, low N treatments decreased net influxes of NH4 + and NO3 –, root NH4 + and foliar NO3 – content, root NR activities, total N concentration in roots and leaves, and transcript levels of most ammonium (AMTs) and nitrate (NRTs) transporter genes in leaves and genes involved in N assimilation in roots and leaves. Low N availability increased fine root surface area, foliar starch concentration, δ15N in roots and leaves, and transcript abundance of several AMTs (e.g. AMT1;2) and NRTs (e.g. NRT1;2 and NRT2;4B) in roots of both species. These data indicate that poplar species slow down processes of N acquisition and assimilation in acclimation to limiting N supply. PMID:23963674

Mandibular molar root morphology in Neanderthals and Late Pleistocene and recent Homo sapiens.

PubMed

Kupczik, Kornelius; Hublin, Jean-Jacques

2010-11-01

Neanderthals have a distinctive suite of dental features, including large anterior crown and root dimensions and molars with enlarged pulp cavities. Yet, there is little known about variation in molar root morphology in Neanderthals and other recent and fossil members of Homo. Here, we provide the first comprehensive metric analysis of permanent mandibular molar root morphology in Middle and Late Pleistocene Homo neanderthalensis, and Late Pleistocene (Aterian) and recent Homo sapiens. We specifically address the question of whether root form can be used to distinguish between these groups and assess whether any variation in root form can be related to differences in tooth function. We apply a microtomographic imaging approach to visualise and quantify the external and internal dental morphologies of both isolated molars and molars embedded in the mandible (n=127). Univariate and multivariate analyses reveal both similarities (root length and pulp volume) and differences (occurrence of pyramidal roots and dental tissue volume proportion) in molar root morphology among penecontemporaneous Neanderthals and Aterian H. sapiens. In contrast, the molars of recent H. sapiens are markedly smaller than both Pleistocene H. sapiens and Neanderthals, but share with the former the dentine volume reduction and a smaller root-to-crown volume compared with Neanderthals. Furthermore, we found the first molar to have the largest average root surface area in recent H. sapiens and Neanderthals, although in the latter the difference between M(1) and M(2) is small. In contrast, Aterian H. sapiens root surface areas peak at M(2). Since root surface area is linked to masticatory function, this suggests a distinct occlusal loading regime in Neanderthals compared with both recent and Pleistocene H. sapiens. Copyright © 2010 Elsevier Ltd. All rights reserved.

Partitioning of current photosynthate to different chemical fractions in leaves, stems, and roots of northern red oak seedlings during episodic growth

Treesearch

Richard E. Dickson; Patricia T. Tomlinson; J. G. Isebrands

2000-01-01

The episodic or flushing growth habit of northern red oak (Quercus rubra L.,) has a significant influence on carbon fixation, carbon transport from source leaves, and carbon allocation within the plant; however, the impact of episodic growth on carbon parciprioning among chemical fractions is unknown. Median-flush leaves of the first and second flush...

Modelling the diurnal and seasonal dynamics of soil CO2 exchange in a semiarid ecosystem with high plant-interspace heterogeneity

NASA Astrophysics Data System (ADS)

Gong, Jinnan; Wang, Ben; Jia, Xin; Feng, Wei; Zha, Tianshan; Kellomäki, Seppo; Peltola, Heli

2018-01-01

We used process-based modelling to investigate the roles of carbon-flux (C-flux) components and plant-interspace heterogeneities in regulating soil CO2 exchanges (FS) in a dryland ecosystem with sparse vegetation. To simulate the diurnal and seasonal dynamics of FS, the modelling considered simultaneously the CO2 production, transport and surface exchanges (e.g. biocrust photosynthesis, respiration and photodegradation). The model was parameterized and validated with multivariate data measured during the years 2013-2014 in a semiarid shrubland ecosystem in Yanchi, northwestern China. The model simulation showed that soil rewetting could enhance CO2 dissolution and delay the emission of CO2 produced from rooting zone. In addition, an ineligible fraction of respired CO2 might be removed from soil volumes under respiration chambers by lateral water flows and root uptakes. During rewetting, the lichen-crusted soil could shift temporally from net CO2 source to sink due to the activated photosynthesis of biocrust but the restricted CO2 emissions from subsoil. The presence of plant cover could decrease the root-zone CO2 production and biocrust C sequestration but increase the temperature sensitivities of these fluxes. On the other hand, the sensitivities of root-zone emissions to water content were lower under canopy, which may be due to the advection of water flows from the interspace to canopy. To conclude, the complexity and plant-interspace heterogeneities of soil C processes should be carefully considered to extrapolate findings from chamber to ecosystem scales and to predict the ecosystem responses to climate change and extreme climatic events. Our model can serve as a useful tool to simulate the soil CO2 efflux dynamics in dryland ecosystems.

Interleukin-1β induces human cementoblasts to support osteoclastogenesis

PubMed Central

Huynh, Nam C-N; Everts, Vincent; Pavasant, Prasit; Ampornaramveth, Ruchanee S

2017-01-01

Injury of the periodontium followed by inflammatory response often leads to root resorption. Resorption is accomplished by osteoclasts and their generation may depend on an interaction with the cells in direct contact with the root, the cementoblasts. Our study aimed to investigate the role of human cementoblasts in the formation of osteoclasts and the effect of interleukin (IL)-1β hereupon. Extracted teeth from healthy volunteers were subjected to sequential digestion by type I collagenase and trypsin. The effect of enzymatic digestion on the presence of cells on the root surface was analyzed by histology. Gene expression of primary human cementoblasts (pHCB) was compared with a human cementoblast cell line (HCEM). The pHCBs were analyzed for their expression of IL-1 receptors as well as of receptor activator of nuclear factor kappa-B ligand (RANKL) and osteoprotegerin (OPG). In a co-culture system consisting of osteoclast precursors (blood monocytes) and pHCBs, the formation of osteoclasts and their resorptive activity was assessed by osteo-assay and ivory slices. The cells obtained after a 120 min enzyme digestion expressed the highest level of bone sialoprotein, similar to that of HCEM. This fraction of isolated cells also shared a similar expression pattern of IL-1 receptors (IL1-R1 and IL1-R2). Treatment with IL-1β potently upregulated RANKL expression but not of OPG. pHCBs were shown to induce the formation of functional osteoclasts. This capacity was significantly stimulated by pretreating the pHCBs with IL-1β prior to their co-culture with human blood monocytes. Our study demonstrated that cementoblasts have the capacity to induce osteoclastogenesis, a capacity strongly promoted by IL-1β. These results may explain why osteoclasts can be formed next to the root of teeth. PMID:29235551

Melt pond fraction and spectral sea ice albedo retrieval from MERIS data - Part 1: Validation against in situ, aerial, and ship cruise data

NASA Astrophysics Data System (ADS)

Istomina, L.; Heygster, G.; Huntemann, M.; Schwarz, P.; Birnbaum, G.; Scharien, R.; Polashenski, C.; Perovich, D.; Zege, E.; Malinka, A.; Prikhach, A.; Katsev, I.

2015-08-01

The presence of melt ponds on the Arctic sea ice strongly affects the energy balance of the Arctic Ocean in summer. It affects albedo as well as transmittance through the sea ice, which has consequences for the heat balance and mass balance of sea ice. An algorithm to retrieve melt pond fraction and sea ice albedo from Medium Resolution Imaging Spectrometer (MERIS) data is validated against aerial, shipborne and in situ campaign data. The results show the best correlation for landfast and multiyear ice of high ice concentrations. For broadband albedo, R2 is equal to 0.85, with the RMS (root mean square) being equal to 0.068; for the melt pond fraction, R2 is equal to 0.36, with the RMS being equal to 0.065. The correlation for lower ice concentrations, subpixel ice floes, blue ice and wet ice is lower due to ice drift and challenging for the retrieval surface conditions. Combining all aerial observations gives a mean albedo RMS of 0.089 and a mean melt pond fraction RMS of 0.22. The in situ melt pond fraction correlation is R2 = 0.52 with an RMS = 0.14. Ship cruise data might be affected by documentation of varying accuracy within the Antarctic Sea Ice Processes and Climate (ASPeCt) protocol, which may contribute to the discrepancy between the satellite value and the observed value: mean R2 = 0.044, mean RMS = 0.16. An additional dynamic spatial cloud filter for MERIS over snow and ice has been developed to assist with the validation on swath data.

Empirical and mechanistic evaluation of NH4(+) release kinetic in calcareous soils.

PubMed

Ranjbar, F; Jalali, M

2014-05-01

Release, fixation, and distribution of ammonium (NH4(+)) as a source of nitrogen can play an important role in soil fertility and plant nutrition. In this study, ten surface soils, after addition of 1,000 mg NH4(+) kg(-1,) were incubated for 1 week at the field capacity moisture and 25 ± 2 °C temperature, and then NH4(+) release kinetic was investigated by sequential extractions with 10 mM CaCl2. Furthermore, NH4(+) distribution among three fractions, including water-soluble, exchangeable, and non-exchangeable, was determined in all soil samples. NH4(+) release was initially rapid followed by a slower reaction, and this was described well with the Elovich equation as an empirical model. The cumulative NH4(+) concentration released in spiked soil samples had a positive significant correlation with sand content and negative ones with pH, exchangeable Ca(2+)m and K(+), cation exchange capacity (CEC), equivalent calcium carbonate (ECC), and clay content. The cation exchange model in the PHREEQC program was successful in mechanistic simulation of the release trend of native and added NH4(+) in all control and spiked soil samples. The results of fractionation experiments showed that the non-exchangeable fraction in control and spiked soil samples was greater than that in water-soluble and exchangeable fractions. Soil properties, such as pH, exchangeable Ca(2+) and K(+), CEC, ECC, and contents of sand and clay, had significant influences on the distribution of NH4(+) among three measured fractions. This study indicated that both native and recently fixed NH4(+), added to soil through the application of fertilizers, were readily available for plant roots during 1 week after exposure.

The hexane fraction of Ardisia crispa Thunb. A. DC. roots inhibits inflammation-induced angiogenesis

PubMed Central

2013-01-01

Background Ardisia crispa (Myrsinaceae) is used in traditional Malay medicine to treat various ailments associated with inflammation, including rheumatism. The plant’s hexane fraction was previously shown to inhibit several diseases associated with inflammation. As there is a strong correlation between inflammation and angiogenesis, we conducted the present study to investigate the anti-angiogenic effects of the plant’s roots in animal models of inflammation-induced angiogenesis. Methods We first performed phytochemical screening and high-performance liquid chromatography (HPLC) fingerprinting of the hexane fraction of Ardisia crispa roots ethanolic extract (ACRH) and its quinone-rich fraction (QRF). The anti-inflammatory properties of ACRH and QRF were tested using the Miles vascular permeability assay and the murine air pouch granuloma model following oral administration at various doses. Results Preliminary phytochemical screening of ACRH revealed the presence of flavonoids, triterpenes, and tannins. The QRF was separated from ACRH (38.38% w/w) by column chromatography, and was isolated to yield a benzoquinonoid compound. The ACRH and QRF were quantified by HPLC. The LD50 value of ACRH was 617.02 mg/kg. In the Miles vascular permeability assay, the lowest dose of ACRH (10 mg/kg) and all doses of QRF significantly reduced vascular endothelial growth factor (VEGF)-induced hyperpermeability, when compared with the vehicle control. In the murine air pouch granuloma model, ACRH and QRF both displayed significant and dose-dependent anti-inflammatory effects, without granuloma weight. ACRH and QRF significantly reduced the vascular index, but not granuloma tissue weight. Conclusions In conclusion, both ACRH and QRF showed potential anti-inflammatory properties in a model of inflammation-induced angiogenesis model, demonstrating their potential anti-angiogenic properties. PMID:23298265

Which fraction of soil organic matter is more vulnerable to rhizosphere priming effect?

NASA Astrophysics Data System (ADS)

Zhu, B.; Cheng, W.

2016-12-01

Rhizosphere priming effect (RPE) is defined as the stimulation or suppression of soil organic matter (SOM) decomposition by living roots. It remains unclear which fraction of SOM is more vulnerable to rhizosphere priming. We conducted two experiments in continuous 13CO2 labeling growth chamber to compare the intensity of RPE for the active (or labile) vs. slow (or recalcitrant) SOM. A sandy loam (Alfisol) was incubated at 20oC and 80% water holding capacity for different periods, which created a gradient in the relative proportion of active vs. slow SOM in the remaining soils. We then grew sunflower (Helianthus annuus) and soybean (Glycine max) in these remaining soils for 50 days under the same environmental conditions to compare the RPE of these two plant species on the decomposition of soils that varied in the lability of SOM. In both experiments, as the incubation proceeded from 1 to 8 to 14 months (in experiment 1) and the soil changed from freshly-sampled soil to two-year-incubated soil (in experiment 2), the intensity of RPE increased significantly even after accounting for the changes in root biomass or root-derived CO2. This result suggests that the slow (or recalcitrant) fraction of SOM is likely more vulnerable to rhizosphere priming compared to the active (or labile) fraction of SOM. Although the underlying mechanisms of this finding await further investigation, our study clearly shows that the main component of SOM (slow or recalcitrant SOM, decadal turnover) is vulnerable to rhizosphere priming. Therefore, the RPE has the potential to substantially regulate both short-term and long-term soil carbon dynamics.

Immunoaffinity Knockout of Saponin Glycosides from Asparagus racemosus to Assess Anti-lipid Peroxidation.

PubMed

Onlom, Churanya; Phrompittayarat, Watoo; Putalun, Waraporn; Waranuch, Neti; Ingkaninan, Kornkanok

2017-07-01

Asparagus racemosus Willd (Asparagaceae family), known as Shatavari, is important in Ayurveda and traditional Thai medicines. The saponin glycosides, shatavarin I and IV are major constituents in its roots and may be responsible for their actions including protection against lipid peroxidation and carcinogenesis. To develop an immunoaffinity column for isolating compounds with structures related to shatavarin IV from crude extracts of A. racemosus root. The monoclonal antibody recognising shatavarin IV (mAbShavIV) was coupled to an Affi-Gel Hz gel to isolate compounds with structures related to shatavarin IV from the other components of crude extracts of A. racemosus root. The saponin glycosides in each fraction were analysed by mAbShavIV ELISA and LC-MS/MS. The pooled wash-through fractions contained 3% of loaded mAbShavIV reactive saponin glycosides, while eluted fractions released ~ 90% of shatavarin saponin glycosides in a single step. Using thiobarbiturate (TBARs) to measure lipid-peroxidation, the extract, and the pooled wash-through fractions showed moderate protection against Cu + -induced oxidation of human low density lipoprotein (LDL) (IC 50 11.3 ± 1.4 and 12.6 ± 0.9 μg/mL, respectively). In contrast, the saponin glycosides eluted from the mAbShavIV-column had weaker protectant (IC 50 29.7 ± 1.8 μg/mL) suggesting that A. racemosus shatavarins do not inhibit carcinogenesis through preventing lipid peroxidation. The strategy described here demonstrates its utility for isolating a group of related compounds from the rest of the extract with selectivity and recovery rate. Pharmacological efficacy and synergistic effects of the components obtained can be further investigated. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

Etidronate from Medicine to Endodontics: effects of different irrigation regimes on root dentin roughness

PubMed Central

TARTARI, Talita; DUARTE JUNIOR, Anivaldo Pereira; SILVA JÚNIOR, José Otávio Carrera; KLAUTAU, Eliza Burlamaqui; SILVA E SOUZA JUNIOR, Mario Honorato; SILVA E SOUZA, Patrícia de Almeida Rodrigues

2013-01-01

An increase in dentin roughness, associated with surface composition, contributes to bacterial adherence in recontaminations. Surface roughness is also important for micromechanical interlocking of dental materials to dentin, and understanding the characteristics of the surface is essential to obtain the adhesion of root canal sealers that have different physico-chemical characteristics. Objectives To evaluate the effects of sodium hypochlorite (NaOCl), ethylenediaminetetraacetic (EDTA), etidronic (HEBP), and citric acid (CA) associated with different irrigation regimens on root dentin roughness. Material and Methods Forty-five root halves of anterior teeth were used. The root parts were sectioned in thirds, embedded in acrylic resin and polished to a standard surface roughness. Initially, the samples of each third were randomly assigned into 3 groups and treated as follows: G1 - saline solution (control); G2 - 5% NaOCl+18% HEBP mixed in equal parts; and G3 - 2.5% NaOCl. After initial measuments, the G3 samples were distributed into subgroups G4, G5 and G6, which were subjected to 17% EDTA, 10% CA and 9% HEBP, respectively. Following the new measuments, these groups received a final flush with 2.5% NaOCl, producing G7, G8 and G9. The dentin surface roughness (Ra) was determined before and after treatments using a profilometer. The Wilcoxon test (α<0.05) was used to compare the values before and after treatments, and the Friedman test (α<0.05) to detect any differences among root thirds. Results (i) NaOCl did not affect the surface roughness; (ii) there was a significant increase in roughness after the use of chelating agents (P<0.01); and (iii) only the G3 group showed a difference in surface roughness between apical third and other thirds of the teeth (P<0.0043). Conclusion Only the irrigation regimens that used chelating agents altered the roughness of root dentin. PMID:24212986

Etidronate from medicine to endodontics: effects of different irrigation regimes on root dentin roughness.

PubMed

Tartari, Talita; Duarte Junior, Anivaldo Pereira; Silva Júnior, José Otávio Carrera; Klautau, Eliza Burlamaqui; Silva E Souza Junior, Mario Honorato; Silva E Souza Junior, Patrícia de Almeida Rodrigues

2013-01-01

An increase in dentin roughness, associated with surface composition, contributes to bacterial adherence in recontaminations. Surface roughness is also important for micromechanical interlocking of dental materials to dentin, and understanding the characteristics of the surface is essential to obtain the adhesion of root canal sealers that have different physico-chemical characteristics. To evaluate the effects of sodium hypochlorite (NaOCl), ethylenediaminetetraacetic (EDTA), etidronic (HEBP), and citric acid (CA) associated with different irrigation regimens on root dentin roughness. Forty-five root halves of anterior teeth were used. The root parts were sectioned in thirds, embedded in acrylic resin and polished to a standard surface roughness. Initially, the samples of each third were randomly assigned into 3 groups and treated as follows: G1 - saline solution (control); G2 - 5% NaOCl+18% HEBP mixed in equal parts; and G3 - 2.5% NaOCl. After initial measuments, the G3 samples were distributed into subgroups G4, G5 and G6, which were subjected to 17% EDTA, 10% CA and 9% HEBP, respectively. Following the new measuments, these groups received a final flush with 2.5% NaOCl, producing G7, G8 and G9. The dentin surface roughness (Ra) was determined before and after treatments using a profilometer. The Wilcoxon test (α<0.05) was used to compare the values before and after treatments, and the Friedman test (α<0.05) to detect any differences among root thirds. (i) NaOCl did not affect the surface roughness; (ii) there was a significant increase in roughness after the use of chelating agents (P<0.01); and (iii) only the G3 group showed a difference in surface roughness between apical third and other thirds of the teeth (P<0.0043). Only the irrigation regimens that used chelating agents altered the roughness of root dentin.

Influence of Nano-Hydroxyapatite on the Metal Bioavailability, Plant Metal Accumulation and Root Exudates of Ryegrass for Phytoremediation in Lead-Polluted Soil

PubMed Central

Ding, Ling; Li, Jianbing; Liu, Wei; Zuo, Qingqing; Liang, Shu-xuan

2017-01-01

Lead is recognized as one of the most widespread toxic metal contaminants and pervasive environmental health concerns in the environment. In this paper, the effects of nano-hydroxyapatite (NHAP) on remediation in artificially Pb-contaminated soils and ryegrass were studied in a pot experiment. The addition of NHAP decreased the water- and acid-soluble, exchangeable, and reducible fractions of Pb, extracted using the Community Bureau of Reference (BCR) method, whilst greatly increasing the residual fraction of Pb. Oxidizable Pb was increased slightly. No significant increase in soil pH was caused by the application of NHAP. Compared to conditions without NHAP, the addition of NHAP decreased the Pb content in ryegrass shoots and roots by 13.19–20.3% and 2.86–21.1%, respectively. Therefore, the application of NHAP reduced the mobility and bioavailability of Pb in the soil. In addition, the application of NHAP improved the fresh weight of shoots and roots, and promoted the growth of ryegrass. NHAP played a positive role in stimulating ryegrass to secrete tartaric acid. PMID:28509844

Effect of finishing instrumentation using NiTi hand files on volume, surface area and uninstrumented surfaces in C-shaped root canal systems.

PubMed

Amoroso-Silva, P; Alcalde, M P; Hungaro Duarte, M A; De-Deus, G; Ordinola-Zapata, R; Freire, L G; Cavenago, B C; De Moraes, I G

2017-06-01

To assess the effect of 90°-oscillatory instrumentation with hand files on several morphological parameters (volume, surface area and uninstrumented surface) in C-shaped root canals after instrumentation using a single-file reciprocation system (Reciproc; VDW, Munich, Germany) and a Self-Adjusting File System (SAF; ReDent Nova, Ra'anana, Israel). Twenty mandibular second molars with C-shaped canals and C1 canal configurations were divided into two groups (n = 10) and instrumented with Reciproc and SAF instruments. A size 30 NiTi hand K-file attached to a 90°-oscillatory motion handpiece was used as final instrumentation in both groups. The specimens were scanned using micro-computed tomography after all procedures. Volume, surface area increase and uninstrumented root canal surface were analysed using CTAn software (Bruker-microCT, Kontich, Belgium). Also, the uninstrumented root canal surface was calculated for each canal third. All values were compared between groups using the Mann-Whitney test and within groups using the Wilcoxon's signed-rank test. Instrumentation with Reciproc significantly increased canal volume compared with instrumentation with SAF. Additionally, the canal volumes were significantly increased after 90°-oscillatory instrumentation (between and within group comparison; (P < 0.05)). Regarding the increase in surface area after all instrumentation protocols, statistical analysis only revealed significant differences in the within groups comparison (P < 0.05). Reciproc and SAF instrumentation yielded an uninstrumented root canal surface of 28% and 34%, respectively, which was not significantly different (P > 0.05). Final oscillatory instrumentation significantly reduced the uninstrumented root canal surface from 28% to 9% (Reciproc) and from 34% to 15% (SAF; P < 0.05). The apical and middle thirds exhibited larger uninstrumented root canal surfaces after the first instrumentation that was significantly reduced after oscillatory instrumentation (P < 0.05). The Reciproc and SAF system were associated with similar morphological parameters after instrumentation of mandibular second molars with C-shaped canals except for a higher canal volume increase in the Reciproc group compared to the SAF. Furthermore, the final use of 90°-oscillatory instrumentation using NiTi hand files significantly decreased the uninstrumented canal walls that remained after Reciproc and SAF instrumentation. © 2016 International Endodontic Journal. Published by John Wiley & Sons Ltd.

A novel blue-light phototropic response is revealed in roots of Arabidopsis thaliana in microgravity.

PubMed

Vandenbrink, Joshua P; Herranz, Raul; Medina, F Javier; Edelmann, Richard E; Kiss, John Z

2016-12-01

Blue-light positive phototropism in roots is masked by gravity and revealed in conditions of microgravity. In addition, the magnitude of red-light positive phototropic curvature is correlated to the magnitude of gravity. Due to their sessile nature, plants utilize environmental cues to grow and respond to their surroundings. Two of these cues, light and gravity, play a substantial role in plant orientation and directed growth movements (tropisms). However, very little is currently known about the interaction between light- (phototropic) and gravity (gravitropic)-mediated growth responses. Utilizing the European Modular Cultivation System on board the International Space Station, we investigated the interaction between phototropic and gravitropic responses in three Arabidopsis thaliana genotypes, Landsberg wild type, as well as mutants of phytochrome A and phytochrome B. Onboard centrifuges were used to create a fractional gravity gradient ranging from reduced gravity up to 1g. A novel positive blue-light phototropic response of roots was observed during conditions of microgravity, and this response was attenuated at 0.1g. In addition, a red-light pretreatment of plants enhanced the magnitude of positive phototropic curvature of roots in response to blue illumination. In addition, a positive phototropic response of roots was observed when exposed to red light, and a decrease in response was gradual and correlated with the increase in gravity. The positive red-light phototropic curvature of hypocotyls when exposed to red light was also confirmed. Both red-light and blue-light phototropic responses were also shown to be affected by directional light intensity. To our knowledge, this is the first characterization of a positive blue-light phototropic response in Arabidopsis roots, as well as the first description of the relationship between these phototropic responses in fractional or reduced gravities.

Suberin-Associated Fatty Alcohols in Arabidopsis: Distributions in Roots and Contributions to Seed Coat Barrier Properties1[W

PubMed Central

Vishwanath, Sollapura J.; Kosma, Dylan K.; Pulsifer, Ian P.; Scandola, Sabine; Pascal, Stéphanie; Joubès, Jérôme; Dittrich-Domergue, Franziska; Lessire, René; Rowland, Owen; Domergue, Frédéric

2013-01-01

Suberin is found in a variety of tissues, such as root endoderms and periderms, storage tuber periderms, tree cork layer, and seed coats. It acts as a hydrophobic barrier to control the movement of water, gases, and solutes as well as an antimicrobial barrier. Suberin consists of polymerized phenolics, glycerol, and a variety of fatty acid derivatives, including primary fatty alcohols. We have conducted an in-depth analysis of the distribution of the C18:0 to C22:0 fatty alcohols in Arabidopsis (Arabidopsis thaliana) roots and found that only 20% are part of the root suberin polymer, together representing about 5% of its aliphatic monomer composition, while the remaining 80% are found in the nonpolymeric (soluble) fraction. Down-regulation of Arabidopsis FATTY ACYL REDUCTASE1 (FAR1), FAR4, and FAR5, which collectively produce the fatty alcohols found in suberin, reduced their levels by 70% to 80% in (1) the polymeric and nonpolymeric fractions from roots of tissue culture-grown plants, (2) the suberin-associated root waxes from 7-week-old soil-grown plants, and (3) the seed coat suberin polymer. By contrast, the other main monomers of suberin were not altered, indicating that reduced levels of fatty alcohols did not influence the suberin polymerization process. Nevertheless, the 75% reduction in total fatty alcohol and diol loads in the seed coat resulted in increased permeability to tetrazolium salts and a higher sensitivity to abscisic acid. These results suggest that fatty alcohols and diols play an important role in determining the functional properties of the seed coat suberin barrier. PMID:24019425

A novel blue-light phototropic response is revealed in roots of Arabidopsis thaliana in microgravity

PubMed Central

Vandenbrink, Joshua P.; Herranz, Raul; Medina, F. Javier; Edelmann, Richard E.

2017-01-01

Main conclusion Blue-light positive phototropism in roots is masked by gravity and revealed in conditions of microgravity. In addition, the magnitude of red-light positive phototropic curvature is correlated to the magnitude of gravity. Due to their sessile nature, plants utilize environmental cues to grow and respond to their surroundings. Two of these cues, light and gravity, play a substantial role in plant orientation and directed growth movements (tropisms). However, very little is currently known about the interaction between light- (phototropic) and gravity (gravitropic)-mediated growth responses. Utilizing the European Modular Cultivation System on board the International Space Station, we investigated the interaction between phototropic and gravitropic responses in three Arabidopsis thaliana genotypes, Landsberg wild type, as well as mutants of phytochrome A and phytochrome B. Onboard centrifuges were used to create a fractional gravity gradient ranging from reduced gravity up to 1g. A novel positive blue-light phototropic response of roots was observed during conditions of microgravity, and this response was attenuated at 0.1g. In addition, a red-light pretreatment of plants enhanced the magnitude of positive phototropic curvature of roots in response to blue illumination. In addition, a positive phototropic response of roots was observed when exposed to red light, and a decrease in response was gradual and correlated with the increase in gravity. The positive red-light phototropic curvature of hypocotyls when exposed to red light was also confirmed. Both red-light and blue-light phototropic responses were also shown to be affected by directional light intensity. To our knowledge, this is the first characterization of a positive blue-light phototropic response in Arabidopsis roots, as well as the first description of the relationship between these phototropic responses in fractional or reduced gravities. PMID:27507239

Molecular Genetics of Root Thigmoresponsiveness in Arabidopsis thaliana

NASA Technical Reports Server (NTRS)

Masson, Patrick H.

2002-01-01

The molecular mechanisms that allow plant roots to use gravity and touch as growth guides are investigated. We are using a molecular genetic strategy in Arabidopsis thaliana to study these processes. When Arabidopsis thaliana seedlings grow on tilted hard-agar surfaces, their roots develop a wavy pattern of growth which appears to derive from a succession of left-handed and right-handed circumnutation-like processes triggered by gravity and touch stimulation (Okada and Shimura, 1990; Rutherford et al., 1998; Rutherford and Masson, 1996). Interestingly, mutations that affect root waving on tilted hard-agar surfaces can be identified and characterized. Some of these mutations affect root gravitropism, while others appear to be responsible for the production of abnormal waves (no waves, compressed or square waves, coils) without affecting gravitropism. The specific objectives of this project were to functionally characterize two genes (WVD2 and WVD6) which are required for root waving on tilted agar surfaces, but not for root gravitropism. Specific objectives included a physiological and cytological analysis of the mutants, and molecular cloning and characterization of the corresponding genes. As summarized in this paper, we have reached these objectives. We have also identified and partially characterized other mutations that affect root skewing on hard-agar surfaces (sku5-1 and ago1), and have completed our work on the root-wave phenotype associated with mutations in genes of the tryptophan biosynthesis pathway (Lynn et al., 1999; Rutherford et al., 1998; Sedbrook et al., 2000, 2002). We briefly describe our progress on the cloning and characterization of WVD6, WVD2 and SKU5, and provide a list of papers (published, or in preparation) that derived from this grant. We also discuss the biological implications of our findings, with special emphasis on the analysis of WVD2.

The effect of iron plaque on uptake and translocation of norfloxacin in rice seedlings grown in paddy soil.

PubMed

Yan, Dafang; Ma, Wei; Song, Xiaojing; Bao, Yanyu

2017-03-01

Although the role of iron plaque on rice root surface has been investigated in recent years, its effect on antibiotic uptake remains uncertain. In the study, pot experiment was conducted to investigate the effect of iron plaque on uptake and translocation of norfloxacin (adding 10 and 50 mg·kg -1 treatments) in rice seedlings grown in paddy soil. Iron plaque was induced by adding different amounts of Fe(II) in soil. The results showed that the presence of norfloxacin can decrease the amount of iron plaque induced. After rice with iron plaque induced, norfloxacin was mainly accumulated in iron plaque on root surface, followed by inside root, but its translocation from root to other rice tissues is not observed. Iron plaque played the role of a barrier for norfloxacin uptake into rice roots under high norfloxacin concentration of 50 mg·kg -1 , however not that under low concentration of 10 mg·kg -1 . And the barrier function was the most strongest with adding Fe(II) of 30 mg·kg -1 as combined action of iron plaque and rhizosphere effect. Fluorescence microscope analysis showed that norfloxacin mainly distributed in the outside of root cell, which showed its translocation as apoplastic pathway in rice. Comparing with non-rhizosphere, more norfloxacin was accumulated in rhizosphere soil. Maybe, strong root oxidization (high Eh values) induced more iron oxide formation in rhizosphere and on root surface, which led to norfloxacin's mobility towards to rhizosphere through its strong adsorption of iron oxides and then promoted its uptake by rice on root surface.

Field-Scale Partitioning of Ecosystem Respiration Components Suggests Carbon Stabilization in a Bioenergy Grass Ecosystem

NASA Astrophysics Data System (ADS)

Black, C. K.; Miller, J. N.; Masters, M. D.; Bernacchi, C.; DeLucia, E. H.

2014-12-01

Annually-harvested agroecosystems have the potential to be net carbon sinks only if their root systems allocate sufficient carbon belowground and if this carbon is then retained as stable soil organic matter. Soil respiration measurements are the most common approach to evaluate the stability of soil carbon at experimental time scales, but valid inferences require the partitioning of soil respiration into root-derived (current-year C) and heterotrophic (older C) components. This partitioning is challenging at the field scale because roots and soil are intricately mixed and physical separation in impossible without disturbing the fluxes to be measured. To partition soil flux and estimate the C sink potential of bioenergy crops, we used the carbon isotope difference between C3 and C4 plant species to quantify respiration from roots of three C4 grasses (maize, Miscanthus, and switchgrass) grown in a site with a mixed cropping history where respiration from the breakdown of old soil carbon has a mixed C3-C4 signature. We used a Keeling plot approach to partition fluxes both at the soil surface using soil chambers and from the whole field using continuous flow sampling of air within and above the canopy. Although soil respiration rates from perennial grasses were higher than those from maize, the isotopic signature of respired carbon indicated that the fraction of soil CO2 flux attributable to current-year vegetation was 1.5 (switchgrass) to 2 (Miscanthus) times greater in perennials than that from maize, indicating that soil CO2 flux came mostly from roots and turnover of soil organic matter was reduced in the perennial crops. This reduction in soil heterotrophic respiration, combined with the much greater quantities of C allocated belowground by perennial grasses compared to maize, suggests that perennial grasses grown as bioenergy crops may be able to provide an additional climate benefit by acting as carbon sinks in addition to reducing fossil fuel consumption.

Imaging tree roots with borehole radar

Treesearch

John R. Butnor; Kurt H. Johnsen; Per Wikstrom; Tomas Lundmark; Sune Linder

2006-01-01

Ground-penetrating radar has been used to de-tect and map tree roots using surface-based antennas in reflection mode. On amenable soils these methods can accurately detect lateral tree roots. In some tree species (e.g. Pinus taeda, Pinus palustris), vertically orientated tap roots directly beneath the tree, comprise most of the root mass. It is...

Control of Initialized Fractional-Order Systems. Revised

NASA Technical Reports Server (NTRS)

Hartley, Tom T.; Lorenzo, Carl F.

2002-01-01

Due to the importance of historical effects in fractional-order systems, this paper presents a general fractional-order control theory that includes the time-varying initialization response. Previous studies have not properly accounted for these historical effects. The initialization response, along with the forced response, for fractional-order systems is determined. Stability properties of fractional-order systems are presented in the complex w-plane, which is a transformation of the s-plane. Time responses are discussed with respect to pole positions in the complex w-plane and frequency response behavior is included. A fractional-order vector space representation, which is a generalization of the state space concept, is presented including the initialization response. Control methods for vector representations of initialized fractional-order systems are shown. Nyquist, root-locus, and other input-output control methods are adapted to the control of fractional-order systems. Finally, the fractional-order differintegral is generalized to continuous order-distributions that have the possibility of including a continuum of fractional orders in a system element.

Control of Initialized Fractional-Order Systems

NASA Technical Reports Server (NTRS)

Hartly, Tom T.; Lorenzo, Carl F.

2002-01-01

Due to the importance of historical effects in fractional-order systems, this paper presents a general fractional-order control theory that includes the time-varying initialization response. Previous studies have not properly accounted for these historical effects. The initialization response, along with the forced response, for fractional-order systems is determined. Stability properties of fractional-order systems are presented in the complex Airplane, which is a transformation of the s-plane. Time responses are discussed with respect to pole positions in the complex Airplane and frequency response behavior is included. A fractional-order vector space representation, which is a generalization of the state space concept, is presented including the initialization response. Control methods for vector representations of initialized fractional-order systems are shown. Nyquist, root-locus, and other input-output control methods are adapted to the control of fractional-order systems. Finally, the fractional-order differintegral is generalized to continuous order-distributions that have the possibility of including a continuum of fractional orders in a system element.

Mixed nano/micro-sized calcium phosphate composite and EDTA root surface etching improve availability of graft material in intrabony defects: an in vivo scanning electron microscopy evaluation.

PubMed

Gamal, Ahmed Y; Iacono, Vincent J

2013-12-01

The use of nanoparticles of graft materials may lead to breakthrough applications for periodontal regeneration. However, due to their small particle size, nanoparticles may be eliminated from periodontal defects by phagocytosis. In an attempt to improve nanoparticle retention in periodontal defects, the present in vivo study uses scanning electron microscopy (SEM) to evaluate the potential of micrograft particles of β-tricalcium phosphate (β-TCP) to enhance the binding and retention of nanoparticles of hydroxyapatite (nHA) on EDTA-treated and non-treated root surfaces in periodontal defects after 14 days of healing. Sixty patients having at least two hopeless periodontally affected teeth designated for extraction were randomly divided into four treatment groups (15 patients per group). Patients in group 1 had selected periodontal intrabony defects grafted with nHA of particle size 10 to 100 nm. Patients in group 2 were treated in a similar manner but had the affected roots etched for 2 minutes with a neutral 24% EDTA gel before grafting of the associated vertical defects with nHA. Patients in group 3 had the selected intrabony defects grafted with a composite graft consisting of equal volumes of nHA and β-TCP (particle size 63 to 150 nm). Patients in group 4 were treated as in group 3 but the affected roots were etched with neutral 24% EDTA as in group 2. For each of the four groups, one tooth was extracted immediately, and the second tooth was extracted after 14 days of healing for SEM evaluation. Fourteen days after surgery, all group 1 samples were devoid of any nanoparticles adherent to the root surfaces. Group 2 showed root surface areas 44.7% covered by a single layer of clot-blended grafted particles 14 days following graft application. After 14 days, group 3 samples appeared to retain fibrin strands devoid of grafted particles. Immediately extracted root samples of group 4 had adherent graft particles that covered a considerable area of the root surfaces (88.6%). Grafted particles appeared to cover all samples in a multilayered pattern. After 14 days, the group 4 extracted samples showed multilayered fibrin-covered nano/micro-sized graft particles adherent to the root surfaces (78.5%). The use of a composite graft consisting of nHA and microsized β-TCP after root surface treatment with 24% EDTA may be a suitable method to improve nHA retention in periodontal defects with subsequent graft bioreactivity.

Film depth and concentration banding in free-surface Couette flow of a suspension.

PubMed

Timberlake, Brian D; Morris, Jeffrey F

2003-05-15

The film depth of a free-surface suspension flowing in a partially filled horizontal concentric-cylinder, or Couette, device has been studied in order to assess its role in the axial concentration banding observed in this flow. The flow is driven by rotation of the inner cylinder. The banding phenomenon is characterized by particle-rich bands which under flow appear as elevated regions at the free surface separated axially by regions dilute relative to the mean concentration. The concentric cylinders studied had outer radius R(o) = 2.22 cm and inner radii R(i) = 0.64, 0.95 and 1.27 cm; the suspension, of bulk particle volume fraction phi = 0.2 in all experiments described, was composed of particles of either 250-300 microm diameter or less than 106 microm diameter, with the suspending fluid an equal density liquid of viscosity 160 P. The ratio of the maximum to the minimum particle volume fraction along the axis in the segregated condition varies from O(1) to infinite. The latter case implies complete segregation, with bands of clear fluid separating the concentrated bands. The film depth has been varied through variation of the filled fraction, f, of the annular gap between the cylinders and through the rotation rate. Film depth was analysed by edge detection of video images of the free surface under flow, and the time required for band formation was determined for all conditions at which film depth was studied. The film depth increases roughly as the square root of rotation speed for f = 0.5. Band formation is more rapid for thicker films associated with more rapid rotation rates at f = 0.5, whereas slower formation rates are observed with thicker films caused by large f, f > 0.65. It is observed that the film depth over the inner cylinder grows prior to onset of banding, for as yet unknown reasons. A mechanism for segregation of particles and liquid in film flows based upon 'differential drainage' of the particle and liquid phase in the gravity-driven flow within the film over the inner cylinder is formulated to describe the onset of concentration fluctuations. This model predicts that suspension drainage flows lead to growth of fluctuations in phi under regions of negative surface curvature.

Analysis of growth patterns during gravitropic curvature in roots of Zea mays by use of a computer-based video digitizer

NASA Technical Reports Server (NTRS)

Nelson, A. J.; Evans, M. L.

1986-01-01

A computer-based video digitizer system is described which allows automated tracking of markers placed on a plant surface. The system uses customized software to calculate relative growth rates at selected positions along the plant surface and to determine rates of gravitropic curvature based on the changing pattern of distribution of the surface markers. The system was used to study the time course of gravitropic curvature and changes in relative growth rate along the upper and lower surface of horizontally-oriented roots of maize (Zea mays L.). The growing region of the root was found to extend from about 1 mm behind the tip to approximately 6 mm behind the tip. In vertically-oriented roots the relative growth rate was maximal at about 2.5 mm behind the tip and declined smoothly on either side of the maximum. Curvature was initiated approximately 30 min after horizontal orientation with maximal (50 degrees) curvature being attained in 3 h. Analysis of surface extension patterns during the response indicated that curvature results from a reduction in growth rate along both the upper and lower surfaces with stronger reduction along the lower surface.

Uptake and Distribution of Silver in the Aquatic Plant Landoltia punctata (Duckweed) Exposed to Silver and Silver Sulfide Nanoparticles.

PubMed

Stegemeier, John P; Colman, Benjamin P; Schwab, Fabienne; Wiesner, Mark R; Lowry, Gregory V

2017-05-02

Aquatic ecosystems are expected to receive Ag 0 and Ag 2 S nanoparticles (NPs) through anthropogenic waste streams. The speciation of silver in Ag-NPs affects their fate in ecosystems, but its influence on interactions with aquatic plants is still unclear. Here, the Ag speciation and distribution was measured in an aquatic plant, duckweed (Landoltia punctata), exposed to Ag 0 or Ag 2 S NPs, or to AgNO 3 . The silver distribution in duckweed roots was visualized using synchrotron-based micro X-ray fluorescence (XRF) mapping and Ag speciation was determined using extended X-ray absorption fine structure (EXAFS) spectroscopy. Duckweed exposed to Ag 2 S-NPs or Ag 0 -NPs accumulated similar Ag concentrations despite an order of magnitude smaller dissolved Ag fraction measured in the exposure medium for Ag 2 S-NPs compared to Ag 0 -NPs. By 24 h after exposure, all three forms of silver had accumulated on and partially in the roots regardless of the form of Ag exposed to the plants. Once associated with duckweed tissue, Ag 0 -NPs had transformed primarily into silver sulfide and silver thiol species. This suggests that plant defenses were active within or at the root surface. The Ag 2 S-NPs remained as Ag 2 S, while AgNO 3 exposure led to Ag 0 and sulfur-associated Ag species in plant tissue. Thus, regardless of initial speciation, Ag was readily available to duckweed.

Phytoextraction of toxic trace elements by Sorghum bicolor inoculated with Streptomyces pactum (Act12) in contaminated soils.

PubMed

Ali, Amjad; Guo, Di; Mahar, Amanullah; Wang, Ping; Ma, Fang; Shen, Feng; Li, Ronghua; Zhang, Zengqiang

2017-05-01

The increasing industrial, mining and agricultural activities have intensified the release of potential toxic trace elements (PTEs), which are of great concern to human health and environment. The alarming increase in PTEs concentration, stress the need for biotechnological remediation approaches. In order to assist phytoextraction of PTEs, different combinations of Streptomyces pactum (Act12) with biochar were applied to mining and industrial polluted soils of Shaanxi and Hunan Provinces of China, respectively. Act12 affected soil physico-chemical properties in both soils. Bioavailable Zn and Pb increased due to microbial activities, while Cd decreased by adsorption on biochar surface. Phytoextraction of Zn and Pb occurred in TG and CZ soil, while Cd uptake decreased in iron rich CZ soil by conflicting effect of siderophores. Cd in sorghum shoot was below detection level, but uptake increased in the roots due to minimum available fraction in TG soil. Biochar reduced the shoot and root uptake of Cd. Sorghum shoot, root dry weight and chlorophyll significantly increased after Act12 and biochar application. β-glucosidase, alkaline phosphatase and urease activities were significantly enhanced by Act12. Antioxidant enzymatic activities (POD, PAL and PPO) and lipid peroxidation (MDA) were decreased after the application of Act12 and biochar by reduced PTEs stress. Act12 and biochar can be used for different crops to enumerate the transfer rate of PTEs into the food chain. Copyright © 2017 Elsevier Inc. All rights reserved.

Influence of ethanol on dentin roughness, surface free energy, and interaction between AH Plus and root dentin.

PubMed

Pantoja, Carlos Augusto de Morais Souto; Silva, Diogo Henrique da; Soares, Adriana de Jesus; Ferraz, Caio Cezar Randi; Gomes, Brenda Paula Figueiredo de Almeida; Zaia, Alexandre Augusto; Almeida, José Flávio Affonso de

2018-01-01

This study aimed to evaluate the influence of different ethanol concentrations on dentin roughness, surface free energy, and contact angle between AH Plus and the root canal dentin. One hundred human maxillary anterior teeth were split longitudinally and 200 dentin specimens were polished to make the surface flatter and smoother. An acrylic bar was positioned between two dentin specimens and impression material was added to create a block, simulating an instrumented root canal space. Specimens were removed from the mold and cleaned in an ultrasonic bath for 10 min. Thereafter, dentin specimens were divided into four groups (n = 50) according to the drying methods used: a) wet: vacuum only, b) paper points: vacuum + absorbent paper points, c) 70% alcohol: 70% alcohol (1 min) + vacuum + absorbent paper points, and d) 100% alcohol: 100% alcohol (1 min) + vacuum + absorbent paper points. A rugosimeter and a goniometer were used to verify the roughness (Ra) and to measure the surface free energy and the contact angle between the AH Plus sealer and the root canal dentin. ANOVA and Tukey tests (α = 0.05) were used for statistical analysis. The 70% and 100% ethanol groups showed significantly decreased roughness as well as increased surface free energy in the root canal dentin when compared to the wet and paper point groups. In addition, ethanol significantly reduced the contact angle between the AH Plus sealer and the root canal dentin. Ethanol solutions (70% and 100%) provide better wettability of AH Plus sealer on dentin surfaces.

Diffusion tensor imaging with quantitative evaluation and fiber tractography of lumbar nerve roots in sciatica.

PubMed

Shi, Yin; Zong, Min; Xu, Xiaoquan; Zou, Yuefen; Feng, Yang; Liu, Wei; Wang, Chuanbing; Wang, Dehang

2015-04-01

To quantitatively evaluate nerve roots by measuring fractional anisotropy (FA) values in healthy volunteers and sciatica patients, visualize nerve roots by tractography, and compare the diagnostic efficacy between conventional magnetic resonance imaging (MRI) and DTI. Seventy-five sciatica patients and thirty-six healthy volunteers underwent MR imaging using DTI. FA values for L5-S1 lumbar nerve roots were calculated at three levels from DTI images. Tractography was performed on L3-S1 nerve roots. ROC analysis was performed for FA values. The lumbar nerve roots were visualized and FA values were calculated in all subjects. FA values decreased in compressed nerve roots and declined from proximal to distal along the compressed nerve tracts. Mean FA values were more sensitive and specific than MR imaging for differentiating compressed nerve roots, especially in the far lateral zone at distal nerves. DTI can quantitatively evaluate compressed nerve roots, and DTT enables visualization of abnormal nerve tracts, providing vivid anatomic information and localization of probable nerve compression. DTI has great potential utility for evaluating lumbar nerve compression in sciatica. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

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

PubMed Central

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

2017-01-01

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. PMID:29062153

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

PubMed

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.

Seedling root responses to soil moisture and the identification of a belowground trait spectrum across three growth forms.

PubMed

Larson, Julie E; Funk, Jennifer L

2016-05-01

Root trait variation and plasticity could be key factors differentiating plant performance under drought. However, water manipulation and root measurements are rarely coupled empirically across growth forms to identify whether belowground strategies are generalizable across species. We measured seedling root traits across three moisture levels in 18 Mediterranean forbs, grasses, and woody species. Drought increased the root mass fraction (RMF) and decreased the relative proportion of thin roots (indicated by increased root diameters and decreased specific root length (SRL)), rates of root elongation and growth, plant nitrogen uptake, and plant growth. Although responses varied across species, plasticity was not associated with growth form. Woody species differed from forbs and grasses in many traits, but herbaceous groups were similar. Across water treatments, trait correlations suggested a single spectrum of belowground trade-offs related to resource acquisition and plant growth. While effects of SRL and RMF on plant growth shifted with drought, root elongation rate consistently represented this spectrum. We demonstrate that general patterns of root morphology and plasticity are identifiable across diverse species. Root trait measurements should enhance our understanding of belowground strategy and performance across growth forms, but it will be critical to incorporate plasticity and additional aspects of root function into these efforts. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

Morphological, anatomical, and ultrastructural changes (visualized through scanning electron microscopy) induced in Triticum aestivum by Pb²⁺ treatment.

PubMed

Kaur, Gurpreet; Singh, Harminder Pal; Batish, Daizy Rani; Kohli, Ravinder Kumar

2014-11-01

Lead (Pb) causes severe damage to crops, ecosystems, and humans, and alters the physiology and biochemistry of various plant species. It is hypothesized that Pb-induced metabolic alterations could manifest as structural variations in the roots of plants. In light of this, the morphological, anatomical, and ultrastructural variations (through scanning electron microscopy, SEM) were studied in 4-day-old seedlings of Triticum aestivum grown under Pb stress (0, 8, 16, 40, and 80 mg Pb(2+) l(-1); mild to highly toxic). The toxic effect was more pronounced in radicle growth than on the plumule growth. The SEM of the root of T. aestivum depicted morphological alterations and surface ultrastructural changes. Compared to intact and uniform surface cells in the control roots, cells were irregular and desiccated in Pb(2+)-treated roots. In Pb(2+)-treated roots, the number of root hairs increased manifold, showing dense growth, and these were apparently longer. Apart from the deformity in surface morphology and anatomy of the roots in response to Pb(2+) toxicity, considerable anatomical alterations were also observed. Pb(2+)-treated root exhibited signs of injury in the form of cell distortion, particularly in the cortical cells. The endodermis and pericycle region showed loss of uniformity post Pb(2+) exposure (at 80 mg l(-1) Pb(2+)). The cells appeared to be squeezed with greater depositions observed all over the tissue. The study concludes that Pb(2+) treatment caused structural anomalies and induced anatomical and surface ultrastructural changes in T. aestivum.

Molecular genetics of root gravitropism and waving in Arabidopsis thaliana

NASA Technical Reports Server (NTRS)

Sedbrook, J.; Boonsirichai, K.; Chen, R.; Hilson, P.; Pearlman, R.; Rosen, E.; Rutherford, R.; Batiza, A.; Carroll, K.; Schulz, T.;

Effect of ND:YAG laser irradiation and root planing on the root surface: structural and thermal effects.

PubMed

Wilder-Smith, P; Arrastia, A M; Schell, M J; Liaw, L H; Grill, G; Berns, M W

1995-12-01

Effects of ND:YAG laser irradiation on untreated and root planed tooth roots were investigated to determine whether a cleaning effect and/or removal of smear layer could be achieved without concomitant microstructural or thermal damage. Sixty (60) healthy extracted teeth were either untreated, irradiated only, root planed only, or irradiated and root planed. Intra-pulpal and surface temperatures were monitored during irradiation, then SEM was performed. Smear layer elimination was achieved without inducing hard tissue microstructural damage at 5W, using pulse durations and intervals of 0.1 s, a fluence of 0.77 J/cm2, and a total energy density of approximately 700 J/cm2. However, these results were not consistent in all samples. At these parameters, intra-pulpal temperature increases of 9 to 22 degrees C and surface temperature increases of 18 to 36 degrees C were recorded. Thus, despite their effectiveness for smear layer removal, these parameters may not be appropriate for clinical use as an adjunct to conventional periodontal therapy.

Pectate hydrolases of parsley (Petroselinum crispum) roots.

PubMed

Flodrová, Dana; Dzúrovä, Mária; Lisková, Desana; Mohand, Fairouz Ait; Mislovicová, Danica; Malovícová, Anna; Voburka, Zdenek; Omelková, Jirina; Stratilová, Eva

2007-01-01

The presence of various enzyme forms with terminal action pattern on pectate was evaluated in a protein mixture obtained from parsley roots. Enzymes found in the soluble fraction of roots (juice) were purified to homogeneity according to SDS-PAGE, partially separated by preparative isoelectric focusing and characterized. Three forms with pH optima 3.6, 4.2 and 4.6 clearly preferred substrates with a lower degree of polymerization (oligogalacturonates) while the form with pH optimum 5.2 was a typical exopolygalacturonase [EC 3. 2.1.67] with relatively fast cleavage of polymeric substrate. The forms with pH optima 3.6, 4.2 and 5.2 were released from the pulp, too. The form from the pulp with pH optimum 4.6 preferred higher oligogalacturonates and was not described in plants previously. The production of individual forms in roots was compared with that produced by root cells cultivated on solid medium and in liquid one.

Plant root and shoot dynamics during subsurface obstacle interaction

NASA Astrophysics Data System (ADS)

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.

Lead distribution and its potential risk to the environment: lesson learned from environmental monitoring of abandon mine.

PubMed

Nobuntou, Wanida; Parkpian, Preeda; Oanh, Nguyen Thi Kim; Noomhorm, Athapol; Delaune, R D; Jugsujinda, Aroon

2010-11-01

There are many abandon and existing mines (tin, lead and zinc) in the mountainous areas of Thailand. Toxic elements including heavy metals such as lead (Pb), cadmium (Cd) and arsenic (As) have been released and transported from the mining sites to the adjacent landscape. In Thong Pha Phum District, Kanchanaburi Province, Thailand Pb contamination in the vicinity of the mine has occurred which could lead to potential health problems in downstream communities. To better understand current status of Pb contamination and accumulation in the surrounding environment and potential health impact, surface sediment, soil and plant samples were collected seasonally from representative monitoring sites along the aquatic track or flow regime. Potential health risk was determined using hazard quotient (HQ) as an index for local inhabitants who consume rice. Environmental monitoring illustrated that Pb concentrations in the surface sediment was as high as 869.4 mg kg(-1) dry weight and varied differently among stations sampled. Lead content in agricultural soil ranged between 137.8 to 613.5 mg kg(-1) dry weight and was inversely proportion to the distance from the point source. Moreover Pb was transported from the point source to down hill areas. At the highly polluted monitoring stations (S1, S2, and S3), concentrations of Pb exceeded the maximum allowable concentration for Pb in agricultural soil (300 mg kg(-1)) by 1.7-2 times. The Pb in soil was primarily associated with Fe/Mn oxides bound fraction (46-56%) followed by the organic bound fraction (25-30%). Lead uptake by plant varied and was species dependent. However root and tuber crops like cassava (19.92 mg Pb kg(-1) dry weight) and curcumin (3.25 mg Pb kg(-1) dry weight) could have removed Pb from the soil which suggest growing root crops in Pb contaminated soils should be avoided. However Cd, a co-contaminant at one of monitored stations (S4) yielded rice grain with Cd exceeding the maximum allowable concentration suggesting some potential health risk (HQ = 5.34) if people consume rice grown at this station. Overall result shows a low risk associated with Pb release into the environment.

Convective instability within the Tibetan Lithospheric Mantle (Invited)

NASA Astrophysics Data System (ADS)

Houseman, G. A.; Molnar, P. H.; Evans, L.; England, P. C.

2013-12-01

Studies of seismic surface waves in Asia show that shear-wave speeds at depths of ~120-250km beneath the Tibetan Plateau are higher than is generally observed for continents, other than beneath Archaean cratons. The high-speed layer has been interpreted as continental lithosphere that was thickened during the convergence between India and Asia. This interpretation contradicts conceptual models in which gravitational instabilities remove a significant fraction of the mantle lithosphere beneath Tibet during that convergence. In contrast, the suggestion of relatively recent (post-early-Miocene) surface uplift of the Plateau, inferred from the onset of normal faulting across the plateau, synchronous increased rates of compressional deformation in the surroundings of the the plateau, and widespread volcanism in the northern part of the plateau, implies action of a mechanism that increased the gravitational potential energy of, and temperatures within, the Tibetan lithosphere in a way that would not occur if the mantle lithosphere had simply thickened continually throughout the India-Asia convergence. A resolution to this paradox is suggested by the observation that, while shear-wave speeds are indeed high at depths of 120-250 km beneath the Tibetan plateau, they are anomalously low at shallower depths, implying a temperature inversion that is hard to reconcile with uninterrupted lithospheric thickening. We suggest that the ensemble of observations may be explained by the convective overturn of a lithospheric root that is depleted in iron such that it remains buoyant with respect to normal upper mantle. The increased rate of strain within the Tibetan lithosphere once convergence began reduced its effective viscosity, and continuing convergence thickened the lithospheric root. These conditions led to convective overturn, similar to the original conceptual models, with the difference that the overturn was confined within the root, which remains buoyant with respect to the deeper upper mantle. The intrinsic density difference between the root and underlying asthenosphere need only be as large as the density difference due to ~600 K temperature contrast (i.e., ~ 60 kg/m^3) in order that the lithospheric layer remains in place during convective overturn. Such an overturn can occur on a short geological time scale (~ 10 Myr), with the wavelength of the convective flow field likely to be a small multiple of the ~130 km thickness of the depleted lithospheric layer. The horizontal variations of density and temperature implied by this process would not be detectable using typical surface wave analyses, which lack the necessary horizontal resolution at such depths, but may be detectable using body wave tomography given a sufficiently dense ray coverage from a large aperture surface array. Internal convective overturn is a process that can explain the horizontally averaged depth variation of velocity and an abrupt but delayed heating event at the base of the crust.

4-hydroxyphenylacetic acid derivatives of inositol from dandelion (Taraxacum officinale) root characterised using LC-SPE-NMR and LC-MS techniques.

PubMed

Kenny, O; Smyth, T J; Hewage, C M; Brunton, N P; McLoughlin, P

2014-02-01

The combination of hyphenated techniques, LC-SPE-NMR and LC-MS, to isolate and identify minor isomeric compounds from an ethyl acetate fraction of Taraxacum officinale root was employed in this study. Two distinct fractions of 4-hydroxyphenylacetic acid derivatives of inositol were isolated and characterised by spectroscopic methods. The (1)H NMR spectra and MS data revealed two groups of compounds, one of which were derivatives of the di-4-hydroxyphenylacetic acid derivative of the inositol compound tetrahydroxy-5-[2-(4-hydroxyphenyl)acetyl] oxycyclohexyl-2-(4-hydroxyphenyl) acetate, while the other group consisted of similar tri-substituted inositol derivatives. For both fractions the derivatives of inositols vary in the number of 4-hydroxyphenylacetic acid groups present and their position and geometry on the inositol ring. In total, three di-substituted and three tri-substituted 4-hydroxyphenylacetic acid inositol derivates were identified for the first time along with a further two previously reported di-substituted inositol derivatives. Copyright © 2013 Elsevier Ltd. All rights reserved.

Enhancing a Remote-Sensing Method for Soil Moisture by Accounting for Regional Soil, Vegetation, and Climatic Characteristics

NASA Astrophysics Data System (ADS)

Sahaar, A. S.; Niemann, J. D.

2016-12-01

Accurate knowledge of root-zone soil moisture is critical for understanding the perpetuation of droughts and managing agricultural water systems. A remote-sensing method based on optical and thermal satellite imagery has been previously proposed to estimate fine-resolution (30 m) root-zone soil moisture over large regions. This method uses Landsat imagery to calculate all the components of the surface energy balance and then calculates the evaporative fraction (Λ) as the ratio of the latent heat flux to the sum of the sensible and latent heat fluxes. Root-zone soil moisture (θ) is then estimated from an empirical relationship with Λ. A similar approach has also been proposed to estimate the degree of saturation. Previous testing of this method for a semiarid region of southeastern Colorado has shown that a single relationship between θ and Λ does not apply universally. The primary objective of this study is to evaluate the impact of regional soil, vegetation, and climatic conditions on the form and strength of the Λ- θ relationship. To accomplish this goal, a global sensitivity analysis is performed using the Extended Fourier Amplitude Sensitivity Test (FAST) and a physically-based model (Hydrus-1D) that simulates both the land-surface energy balance and soil moisture dynamics. The modeling results show that, within a given climatic region, soil characteristics are very important in determining the shape of the Λ-θ relationship, while vegetation characteristics have the largest effect on the strength of the relationship. The modeling results also indicate that the annual average rainfall, which helps determine the climatic region, has a strong effect on both the form and strength of the relationship. From this analysis, the constants that define the Λ-θ relationships are estimated using regional characteristics. This approach allows the remote-sensing method to be adapted to local conditions and has the potential to greatly improve its performance.

The accumulation and subcellular distribution of arsenic and antimony in four fern plants.

PubMed

Feng, R; Wang, X; Wei, C; Tu, S

2015-01-01

In the present study, Pteris cretica 'Albo-Lineata' (PC), Pteris fauriei (PF), Humata tyermanii Moore (HT), and Pteris ensiformis Burm (PE), were selected to explore additional plant materials for the phytoremediation of As and Sb co-contamination. To some extent, the addition of As and Sb enhanced the growth of HT, PE, and PF. Conversely, the addition of As and Sb negatively affected the growth of PC and was accompanied with the accumulation of high levels of As and Sb in the roots. The highest concentration of Sb was recorded as 6405 mg kg(-1) in the roots of PC, and that for As was 337 mg kg(-1) in the rhizome of PF. To some degree, As and Sb stimulated the uptake of each other in these ferns. Arsenic was mainly stored in the cytoplasmic supernatant (CS) fraction, followed by the cell wall (CW) fraction. In contrast, Sb was mainly found in the CW fraction and, to a lesser extent, in the CS fraction, suggesting that the cell wall and cytosol play different roles in As and Sb accumulation by fern plants. This study demonstrated that these fern plants show a good application potential in the phytoremediation of As and Sb co-contaminated environments.

Differential Activity of Striga hermonthica Seed Germination Stimulants and Gigaspora rosea Hyphal Branching Factors in Rice and Their Contribution to Underground Communication

PubMed Central

Cardoso, Catarina; Charnikhova, Tatsiana; Jamil, Muhammad; Delaux, Pierre-Marc; Verstappen, Francel; Amini, Maryam; Lauressergues, Dominique; Ruyter-Spira, Carolien; Bouwmeester, Harro

2014-01-01

Strigolactones (SLs) trigger germination of parasitic plant seeds and hyphal branching of symbiotic arbuscular mycorrhizal (AM) fungi. There is extensive structural variation in SLs and plants usually produce blends of different SLs. The structural variation among natural SLs has been shown to impact their biological activity as hyphal branching and parasitic plant seed germination stimulants. In this study, rice root exudates were fractioned by HPLC. The resulting fractions were analyzed by MRM-LC-MS to investigate the presence of SLs and tested using bioassays to assess their Striga hermonthica seed germination and Gigaspora rosea hyphal branching stimulatory activities. A substantial number of active fractions were revealed often with very different effect on seed germination and hyphal branching. Fractions containing (−)−orobanchol and ent-2'-epi-5-deoxystrigol contributed little to the induction of S. hermonthica seed germination but strongly stimulated AM fungal hyphal branching. Three SLs in one fraction, putative methoxy-5-deoxystrigol isomers, had moderate seed germination and hyphal branching inducing activity. Two fractions contained strong germination stimulants but displayed only modest hyphal branching activity. We provide evidence that these stimulants are likely SLs although no SL-representative masses could be detected using MRM-LC-MS. Our results show that seed germination and hyphal branching are induced to very different extents by the various SLs (or other stimulants) present in rice root exudates. We propose that the development of rice varieties with different SL composition is a promising strategy to reduce parasitic plant infestation while maintaining symbiosis with AM fungi. PMID:25126953

The formation of 3 alpha- and 3 beta-acetoxytropanes by Datura stramonium transformed root cultures involves two acetyl-CoA-dependent acyltransferases.

PubMed

Robins, R J; Bachmann, P; Robinson, T; Rhodes, M J; Yamada, Y

1991-11-04

Tropine (tropan-3 alpha-ol) is an intermediate in the formation of hyoscyamine. An acyltransferase activity that can acetylate tropine using acetylcoenzyme A as cosubstrate has been found in transformed root cultures of Datura stramonium. A further acyltransferase activity that acetylates pseudotropine (tropan-3 beta-ol) with acetyl-coenzyme A is also present. These two activities can be partially resolved by anion-exchange chromatography, some fractions containing only the pseudotropine-utilizing activity. The basic properties of these two enzymes are reported and their roles in forming the observed alkaloid spectrum of D. stramonium roots discussed.

Isolation and partial purification of cadmium-binding protein from roots of the grass Agrostis gigantea

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

Rauser, W.E.

1984-04-01

A cadmium-binding protein was isolated from roots of the grass Agrostis gigantea Roth. Heat-stable proteins were chromatographed on the anion exchanger QAE-Sephadex A-25. The major cadmium fraction was purified further by gel filtration of Sephadex G-75 in 1 molar KCI buffer. The resulting protein preparation was light brown, had an apparent molecular weight of 3700, contained 29% cysteine and close to 4 gram atoms cadmium/mole. The cadmium:cysteine ratio was l:2.7. Spectroscopic measurments indicated cadmium-thiolate coordination. The roots produced the metallothionein-like protein when they were exposed to cadmium for 7 days.

Differential Responses of Soybean and Sorghum Growth, Nitrogen Uptake, and Microbial Metabolism in the Rhizosphere to Cattle Manure Application: A Rhizobox Study.

PubMed

Chu, Qingnan; Sha, Zhimin; Nakamura, Takuji; Oka, Norikuni; Osaki, Mitsuru; Watanabe, Toshihiro

2016-11-02

In this study, we determined the capacity of soybean (Glycine max L. Merr. cv. Hoyoharuka) and sorghum (Sorghum bicolor L. Moench. cv. Hybrid Sorgo) to utilize different forms of nitrogen (N) in a rhizobox system. Seedlings were grown for 35 days without N or with 130 mg N kg -1 soil as ammonium sulfate or farmyard cattle manure. The soil fractions at different distances from the root were sliced millimeter by millimeter in the rhizobox system. We assessed the distribution of different forms of N and microbial metabolism in different soil fractions in the rhizosphere. There are no treatment-dependent changes in biomass production in the roots and shoots of soybeans, however, the ammonium and manure treatment yielded 1.30 and 1.40 times higher shoot biomass of sorghum than the control. Moreover, the depletion of inorganic N and total amino acids (TAA) in the rhizosphere was largely undetectable at various distances from the soybean roots regardless of the treatments employed. The addition of ammonium sulfate resulted in a decrease in the nitrate concentration gradient as the distance decreased from the sorghum roots. The addition of manure to the soil increased the N content in the sorghum shoots, 1.57 times higher than the control; this increase was negatively correlated with the concentrations of TAA in the soil of the root compartment. In addition, the application of manure simultaneously induced TAA depletion (i.e., the TAA concentration in root compartment was 1.48 times higher than that in bulk soil) and greater microbial activity and diversity in the sorghum rhizosphere, where higher microbial consumption of asparagine, glutamic acid, and phenylalanine were also observed near the roots. Our results are first to present the evidence that sorghum may possess a high capacity for taking up amino acids as a consequence of organic matter application, and microbial metabolism.

Analysis of radiological parameters associated with decreased fractional anisotropy values on diffusion tensor imaging in patients with lumbar spinal stenosis.

PubMed

Wang, Xiandi; Wang, Hongli; Sun, Chi; Zhou, Shuyi; Meng, Tao; Lv, Feizhou; Ma, Xiaosheng; Xia, Xinlei; Jiang, Jianyuan

2018-04-26

Previous studies have indicated that decreased fractional anisotropy (FA) values on diffusion tensor imaging (DTI) are well correlated with the symptoms of nerve root compression. The aim of our study is to determine primary radiological parameters associated with decreased FA values in patients with lumbar spinal stenosis involving single L5 nerve root. Patients confirmed with single L5 nerve root compression by transforaminal nerve root blocks were included in this study. FA values of L5 nerve roots on both symptomatic and asymptomatic side were obtained. Conventional radiological parameters, such as disc height, degenerative scoliosis, dural sac cross-sectional area (DSCSA), foraminal height (FH), hypertrophic facet joint degeneration (HFJD), sagittal rotation (SR), sedimentation sign, sagittal translation and traction spur were measured. Correlation and regression analyses were performed between the radiological parameters and FA values of the symptomatic L5 nerve roots. A predictive regression equation was established. Twenty-one patients were included in this study. FA values were significantly lower at the symptomatic side comparing to the asymptomatic side (0.263 ± 0.069 vs. 0.334 ± 0.080, P = 0.038). DSCSA, FH, HFJD, and SR were significantly correlated with the decreased FA values, with r = 0.518, 0.443, 0.472 and - 0.910, respectively (P < 0.05). DSCSA and SR were found to be the primary radiological parameters related to the decreased FA values, and the regression equation is FA = - 0.012 × SR + 0.002 × DSCSA. DSCSA and SR were primary contributors to decreased FA values in LSS patients involving single L5 nerve root, indicating that central canal decompression and segmental stability should be the first considerations in preoperative planning of these patients. These slides can be retrieved under Electronic Supplementary Material.

Can oxygen stable isotopes be used to track precipitation moisture source in vascular plant-dominated peatlands?

NASA Astrophysics Data System (ADS)

Amesbury, Matthew J.; Charman, Dan J.; Newnham, Rewi M.; Loader, Neil J.; Goodrich, Jordan; Royles, Jessica; Campbell, David I.; Keller, Elizabeth D.; Baisden, W. Troy; Roland, Thomas P.; Gallego-Sala, Angela V.

2015-11-01

Variations in the isotopic composition of precipitation are determined by fractionation processes which occur during temperature- and humidity-dependent phase changes associated with evaporation and condensation. Oxygen stable isotope ratios have therefore been frequently used as a source of palaeoclimate data from a variety of proxy archives, which integrate this signal over time. Applications from ombrotrophic peatlands, where the source water used in cellulose synthesis is derived solely from precipitation, have been mostly limited to Northern Hemisphere Sphagnum-dominated bogs, with few in the Southern Hemisphere or in peatlands dominated by vascular plants. New Zealand (NZ) provides an ideal location to undertake empirical research into oxygen isotope fractionation in vascular peatlands because single taxon analysis can be easily carried out, in particular using the preserved root matrix of the restionaceous wire rush (Empodisma spp.) that forms deep Holocene peat deposits throughout the country. Furthermore, large gradients are observed in the mean isotopic composition of precipitation across NZ, caused primarily by the relative influence of different climate modes. Here, we test whether δ18O of Empodisma α-cellulose from ombrotrophic restiad peatlands in NZ can provide a methodology for developing palaeoclimate records of past precipitation δ18O. Surface plant, water and precipitation samples were taken over spatial (six sites spanning >10° latitude) and temporal (monthly measurements over one year) gradients. A link between the isotopic composition of root-associated water, the most likely source water for plant growth, and precipitation in both datasets was found. Back-trajectory modelling of precipitation moisture source for rain days prior to sampling showed clear seasonality in the temporal data that was reflected in root-associated water. The link between source water and plant cellulose was less clear, although mechanistic modelling predicted mean cellulose values within published error margins for both datasets. Improved physiological understanding and modelling of δ18O in restiad peatlands should enable use of this approach as a new source of palaeoclimate data to reconstruct changes in past atmospheric circulation.

Identifying the optimal spatially and temporally invariant root distribution for a semiarid environment

NASA Astrophysics Data System (ADS)

Sivandran, Gajan; Bras, Rafael L.

2012-12-01

In semiarid regions, the rooting strategies employed by vegetation can be critical to its survival. Arid regions are characterized by high variability in the arrival of rainfall, and species found in these areas have adapted mechanisms to ensure the capture of this scarce resource. Vegetation roots have strong control over this partitioning, and assuming a static root profile, predetermine the manner in which this partitioning is undertaken.A coupled, dynamic vegetation and hydrologic model, tRIBS + VEGGIE, was used to explore the role of vertical root distribution on hydrologic fluxes. Point-scale simulations were carried out using two spatially and temporally invariant rooting schemes: uniform: a one-parameter model and logistic: a two-parameter model. The simulations were forced with a stochastic climate generator calibrated to weather stations and rain gauges in the semiarid Walnut Gulch Experimental Watershed (WGEW) in Arizona. A series of simulations were undertaken exploring the parameter space of both rooting schemes and the optimal root distribution for the simulation, which was defined as the root distribution with the maximum mean transpiration over a 100-yr period, and this was identified. This optimal root profile was determined for five generic soil textures and two plant-functional types (PFTs) to illustrate the role of soil texture on the partitioning of moisture at the land surface. The simulation results illustrate the strong control soil texture has on the partitioning of rainfall and consequently the depth of the optimal rooting profile. High-conductivity soils resulted in the deepest optimal rooting profile with land surface moisture fluxes dominated by transpiration. As we move toward the lower conductivity end of the soil spectrum, a shallowing of the optimal rooting profile is observed and evaporation gradually becomes the dominate flux from the land surface. This study offers a methodology through which local plant, soil, and climate can be accounted for in the parameterization of rooting profiles in semiarid regions.

First observation of B(s)(0) --> D(s)(+/-)K(-/+) and measurement of the ratio of branching fractions B(B(s)(0) --> D(s)(+/-)K(-/+)/B(B(s)(0) --> D(s)(+)pi(-)).

PubMed

Aaltonen, T; Adelman, J; Akimoto, T; Albrow, M G; Alvarez González, B; Amerio, S; Amidei, D; Anastassov, A; Annovi, A; Antos, J; Apollinari, G; Apresyan, A; Arisawa, T; Artikov, A; Ashmanskas, W; Attal, A; Aurisano, A; Azfar, F; Azzurri, P; Badgett, W; Barbaro-Galtieri, A; Barnes, V E; Barnett, B A; Bartsch, V; Bauer, G; Beauchemin, P-H; Bedeschi, F; Bednar, P; Beecher, D; Behari, S; Bellettini, G; Bellinger, J; Benjamin, D; Beretvas, A; Beringer, J; Bhatti, A; Binkley, M; Bisello, D; Bizjak, I; Blair, R E; Blocker, C; Blumenfeld, B; Bocci, A; Bodek, A; Boisvert, V; Bolla, G; Bortoletto, D; Boudreau, J; Boveia, A; Brau, B; Bridgeman, A; Brigliadori, L; Bromberg, C; Brubaker, E; Budagov, J; Budd, H S; Budd, S; Burkett, K; Busetto, G; Bussey, P; Buzatu, A; Byrum, K L; Cabrera, S; Calancha, C; Campanelli, M; Campbell, M; Canelli, F; Canepa, A; Carlsmith, D; Carosi, R; Carrillo, S; Carron, S; Casal, B; Casarsa, M; Castro, A; Catastini, P; Cauz, D; Cavaliere, V; Cavalli-Sforza, M; Cerri, A; Cerrito, L; Chang, S H; Chen, Y C; Chertok, M; Chiarelli, G; Chlachidze, G; Chlebana, F; Cho, K; Chokheli, D; Chou, J P; Choudalakis, G; Chuang, S H; Chung, K; Chung, W H; Chung, Y S; Ciobanu, C I; Ciocci, M A; Clark, A; Clark, D; Compostella, G; Convery, M E; Conway, J; Copic, K; Cordelli, M; Cortiana, G; Cox, D J; Crescioli, F; Cuenca Almenar, C; Cuevas, J; Culbertson, R; Cully, J C; Dagenhart, D; Datta, M; Davies, T; de Barbaro, P; De Cecco, S; Deisher, A; De Lorenzo, G; Dell'Orso, M; Deluca, C; Demortier, L; Deng, J; Deninno, M; Derwent, P F; di Giovanni, G P; Dionisi, C; Di Ruzza, B; Dittmann, J R; D'Onofrio, M; Donati, S; Dong, P; Donini, J; Dorigo, T; Dube, S; Efron, J; Elagin, A; Erbacher, R; Errede, D; Errede, S; Eusebi, R; Fang, H C; Farrington, S; Fedorko, W T; Feild, R G; Feindt, M; Fernandez, J P; Ferrazza, C; Field, R; Flanagan, G; Forrest, R; Franklin, M; Freeman, J C; Furic, I; Gallinaro, M; Galyardt, J; Garberson, F; Garcia, J E; Garfinkel, A F; Genser, K; Gerberich, H; Gerdes, D; Gessler, A; Giagu, S; Giakoumopoulou, V; Giannetti, P; Gibson, K; Gimmell, J L; Ginsburg, C M; Giokaris, N; Giordani, M; Giromini, P; Giunta, M; Giurgiu, G; Glagolev, V; Glenzinski, D; Gold, M; Goldschmidt, N; Golossanov, A; Gomez, G; Gomez-Ceballos, G; Goncharov, M; González, O; Gorelov, I; Goshaw, A T; Goulianos, K; Gresele, A; Grinstein, S; Grosso-Pilcher, C; Group, R C; Grundler, U; Guimaraes da Costa, J; Gunay-Unalan, Z; Haber, C; Hahn, K; Hahn, S R; Halkiadakis, E; Han, B-Y; Han, J Y; Handler, R; Happacher, F; Hara, K; Hare, D; Hare, M; Harper, S; Harr, R F; Harris, R M; Hartz, M; Hatakeyama, K; Hauser, J; Hays, C; Heck, M; Heijboer, A; Heinemann, B; Heinrich, J; Henderson, C; Herndon, M; Heuser, J; Hewamanage, S; Hidas, D; Hill, C S; Hirschbuehl, D; Hocker, A; Hou, S; Houlden, M; Hsu, S-C; Huffman, B T; Hughes, R E; Husemann, U; Huston, J; Incandela, J; Introzzi, G; Iori, M; Ivanov, A; James, E; Jayatilaka, B; Jeon, E J; Jha, M K; Jindariani, S; Johnson, W; Jones, M; Joo, K K; Jun, S Y; Jung, J E; Junk, T R; Kamon, T; Kar, D; Karchin, P E; Kato, Y; Kephart, R; Keung, J; Khotilovich, V; Kilminster, B; Kim, D H; Kim, H S; Kim, J E; Kim, M J; Kim, S B; Kim, S H; Kim, Y K; Kimura, N; Kirsch, L; Klimenko, S; Knuteson, B; Ko, B R; Koay, S A; Kondo, K; Kong, D J; Konigsberg, J; Korytov, A; Kotwal, A V; Kreps, M; Kroll, J; Krop, D; Krumnack, N; Kruse, M; Krutelyov, V; Kubo, T; Kuhr, T; Kulkarni, N P; Kurata, M; Kusakabe, Y; Kwang, S; Laasanen, A T; Lami, S; Lammel, S; Lancaster, M; Lander, R L; Lannon, K; Lath, A; Latino, G; Lazzizzera, I; LeCompte, T; Lee, E; Lee, H S; Lee, S W; Leone, S; Lewis, J D; Lin, C S; Linacre, J; Lindgren, M; Lipeles, E; Lister, A; Litvintsev, D O; Liu, C; Liu, T; Lockyer, N S; Loginov, A; Loreti, M; Lovas, L; Lu, R-S; Lucchesi, D; Lueck, J; Luci, C; Lujan, P; Lukens, P; Lungu, G; Lyons, L; Lys, J; Lysak, R; Lytken, E; Mack, P; MacQueen, D; Madrak, R; Maeshima, K; Makhoul, K; Maki, T; Maksimovic, P; Malde, S; Malik, S; Manca, G; Manousakis-Katsikakis, A; Margaroli, F; Marino, C; Marino, C P; Martin, A; Martin, V; Martínez, M; Martínez-Ballarín, R; Maruyama, T; Mastrandrea, P; Masubuchi, T; Mattson, M E; Mazzanti, P; McFarland, K S; McIntyre, P; McNulty, R; Mehta, A; Mehtala, P; Menzione, A; Merkel, P; Mesropian, C; Miao, T; Miladinovic, N; Miller, R; Mills, C; Milnik, M; Mitra, A; Mitselmakher, G; Miyake, H; Moggi, N; Moon, C S; Moore, R; Morello, M J; Morlok, J; Movilla Fernandez, P; Mülmenstädt, J; Mukherjee, A; Muller, Th; Mumford, R; Murat, P; Mussini, M; Nachtman, J; Nagai, Y; Nagano, A; Naganoma, J; Nakamura, K; Nakano, I; Napier, A; Necula, V; Neu, C; Neubauer, M S; Nielsen, J; Nodulman, L; Norman, M; Norniella, O; Nurse, E; Oakes, L; Oh, S H; Oh, Y D; Oksuzian, I; Okusawa, T; Orava, R; Osterberg, K; Pagan Griso, S; Pagliarone, C; Palencia, E; Papadimitriou, V; Papaikonomou, A; Paramonov, A A; Parks, B; Pashapour, S; Patrick, J; Pauletta, G; Paulini, M; Paus, C; Pellett, D E; Penzo, A; Phillips, T J; Piacentino, G; Pianori, E; Pinera, L; Pitts, K; Plager, C; Pondrom, L; Poukhov, O; Pounder, N; Prakoshyn, F; Pronko, A; Proudfoot, J; Ptohos, F; Pueschel, E; Punzi, G; Pursley, J; Rademacker, J; Rahaman, A; Ramakrishnan, V; Ranjan, N; Redondo, I; Reisert, B; Rekovic, V; Renton, P; Rescigno, M; Richter, S; Rimondi, F; Ristori, L; Robson, A; Rodrigo, T; Rodriguez, T; Rogers, E; Rolli, S; Roser, R; Rossi, M; Rossin, R; Roy, P; Ruiz, A; Russ, J; Rusu, V; Saarikko, H; Safonov, A; Sakumoto, W K; Saltó, O; Santi, L; Sarkar, S; Sartori, L; Sato, K; Savoy-Navarro, A; Scheidle, T; Schlabach, P; Schmidt, A; Schmidt, E E; Schmidt, M A; Schmidt, M P; Schmitt, M; Schwarz, T; Scodellaro, L; Scott, A L; Scribano, A; Scuri, F; Sedov, A; Seidel, S; Seiya, Y; Semenov, A; Sexton-Kennedy, L; Sfyrla, A; Shalhout, S Z; Shapiro, M D; Shears, T; Shepard, P F; Sherman, D; Shimojima, M; Shiraishi, S; Shochet, M; Shon, Y; Shreyber, I; Sidoti, A; Sinervo, P; Sisakyan, A; Slaughter, A J; Slaunwhite, J; Sliwa, K; Smith, J R; Snider, F D; Snihur, R; Soha, A; Somalwar, S; Sorin, V; Spalding, J; Spreitzer, T; Squillacioti, P; Stanitzki, M; St Denis, R; Stelzer, B; Stelzer-Chilton, O; Stentz, D; Strologas, J; Stuart, D; Suh, J S; Sukhanov, A; Suslov, I; Suzuki, T; Taffard, A; Takashima, R; Takeuchi, Y; Tanaka, R; Tecchio, M; Teng, P K; Terashi, K; Thom, J; Thompson, A S; Thompson, G A; Thomson, E; Tipton, P; Tiwari, V; Tkaczyk, S; Toback, D; Tokar, S; Tollefson, K; Tomura, T; Tonelli, D; Torre, S; Torretta, D; Totaro, P; Tourneur, S; Tu, Y; Turini, N; Ukegawa, F; Vallecorsa, S; van Remortel, N; Varganov, A; Vataga, E; Vázquez, F; Velev, G; Vellidis, C; Veszpremi, V; Vidal, M; Vidal, R; Vila, I; Vilar, R; Vine, T; Vogel, M; Volobouev, I; Volpi, G; Würthwein, F; Wagner, P; Wagner, R G; Wagner, R L; Wagner-Kuhr, J; Wagner, W; Wakisaka, T; Wallny, R; Wang, S M; Warburton, A; Waters, D; Weinberger, M; Wester, W C; Whitehouse, B; Whiteson, D; Wicklund, A B; Wicklund, E; Williams, G; Williams, H H; Wilson, P; Winer, B L; Wittich, P; Wolbers, S; Wolfe, C; Wright, T; Wu, X; Wynne, S M; Xie, S; Yagil, A; Yamamoto, K; Yamaoka, J; Yang, U K; Yang, Y C; Yao, W M; Yeh, G P; Yoh, J; Yorita, K; Yoshida, T; Yu, G B; Yu, I; Yu, S S; Yun, J C; Zanello, L; Zanetti, A; Zaw, I; Zhang, X; Zheng, Y; Zucchelli, S

2009-11-06

A combined mass and particle identification fit is used to make the first observation of the decay B(s)(0) --> D(s)(+/-)K(-/+) and measure the branching fraction of B(s)(0) --> D(s)(+/-)K(-/+) relative to B(s)(0) --> D(s)(+)pi(-). This analysis uses 1.2 fb(-1) integrated luminosity of pp collisions at square root(s) = 1.96 TeV collected with the CDF II detector at the Fermilab Tevatron collider. We observe a B(s)(0) --> D(s)(+/-)K(-/+) signal with a statistical significance of 8.1 sigma and measure B(B(s)(0) --> D(s)(+/-)K(-/+) /B(B(s)(0) --> D(s)(+)pi(-) 0.097+/-0.018(stat) +/- 0.009(syst).

Monoterpene derivatives with anti-allergic activity from red peony root, the root of Paeonia lactiflora.

PubMed

Shi, Yan-Hong; Zhu, Shu; Ge, Yue-Wei; He, Yu-Min; Kazuma, Kohei; Wang, Zhengtao; Yoshimatsu, Kayo; Komatsu, Katsuko

2016-01-01

The methanolic extract and its subfractions from red peony root, the dried roots of Paeonia lactiflora Pallas showed potent antiallergic effects, as inhibition of immunoglobulin E (IgE)-mediated degranulation in rat basophil leukemia (RBL)-2H3 cells. Bioassay-guided fractionation led to the isolation of 16 monoterpene derivatives, including 3 new compounds, paeoniflorol (1), 4'-hydroxypaeoniflorigenone (2) and 4-epi-albiflorin (3), together with 13 known ones (4-16). The chemical structures of the new compounds were elucidated on the basis of spectroscopic and chemical evidences. Among the isolated monoterpene derivatives, nine compounds showed potent anti-allergic effects and compound 1 was the most effective. A primary structure-activity relationship of monoterpene derivatives was discussed. Copyright © 2015 Elsevier B.V. All rights reserved.

Effects of adhesions of amorphous Fe and Al hydroxides on surface charge and adsorption of K+ and Cd2+ on rice roots.

PubMed

Liu, Zhao-Dong; Wang, Hai-Cui; Zhou, Qin; Xu, Ren-Kou

2017-11-01

Iron (Fe) and aluminum (Al) hydroxides in variable charge soils attached to rice roots may affect surface-charge properties and subsequently the adsorption and uptake of nutrients and toxic metals by the roots. Adhesion of amorphous Fe and Al hydroxides onto rice roots and their effects on zeta potential of roots and adsorption of potassium (K + ) and cadmium (Cd 2+ ) by roots were investigated. Rice roots adsorbed more Al hydroxide than Fe hydroxide because of the greater positive charge on Al hydroxide. Adhesion of Fe and Al hydroxides decreased the negative charge on rice roots, and a greater effect of the Al hydroxide. Consequently, adhesion of Fe and Al hydroxides reduced the K + and Cd 2+ adsorption by rice roots. The results of attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) and desorption of K + and Cd 2+ from rice roots indicated that physical masking by Fe and Al hydroxides and diffuse-layer overlapping between the positively-charged hydroxides and negatively-charged roots were responsible for the reduction of negative charge on roots induced by adhesion of the hydroxides. Therefore, the interaction between Fe and Al hydroxides and rice roots reduced negative charge on roots and thus inhibited their adsorption of nutrient and toxic cations. Copyright © 2017 Elsevier Inc. All rights reserved.

Fungi in neotropical epiphyte roots.

PubMed

Bermudes, D; Benzing, D H

1989-01-01

Roots of thirty-eight Ecuadoran vascular epiphytes, representing eleven angiosperm families, were examined for the presence of symbiotic microorganisms. Most orchid roots contained fungal endophytes like those that regularly infect terrestrial counterparts. Hyphae were also common in and on nonorchid roots, but assignments of these relationships to known mycorrhizal morphologies was not possible in all cases. Evidence of vesicular-arbuscular mycorrhizae (VAM) existed in a number of subjects while in Ericaceae and Campanulaceae a fungal association similar to the demateaceous surface fungi (DSF) described for alpine and prarie plants was usually present. Some associations were characterized by multicellular propagules on root surfaces. The significance of these findings and the factors likely to influence occurrence and consequences of root-fungus mutualisms in tropical forest canopies are discussed. Facts and considerations that could aid future inquiry on these systems are provided.

Hepatoprotective and inhibiting HBV effects of polysaccharides from roots of Sophora flavescens.

PubMed

Yang, Hua; Zhou, Zhenhua; He, Lifang; Ma, Hao; Qu, Wensheng; Yin, Jiye; Jia, Mengfan; Zhao, Xiunan; Shan, Junjie; Gao, Yueqiu

2018-03-01

Roots of Sophora flavescens is an important herbal medicine for treatment of HBV and hepatic carcinoma in China. Alkaloids in the root were well known for exhibiting good hepato-protective and anti-HBV effects. However, polysaccharides as main components in the root remained unknown. In the studies, we investigated the chemical features and hepatoprotective effects of Sophora flavescens polysaccharides (SFP-100 and its active fractions) with ConA-induced hepatitis mice, human liver LO2 cells and HepG2.2.15 cells. The results showed that SFP-100 was composed of arabinose, glucose, galactose and galacturonic acid, SFP-100-A mainly contained glucose. SFP-100-B and SFP-100-C were acidic polysaccharides. SFP-100 significantly decreased hepatocytes apoptosis, inhibited the infiltration of neutrophils and macrophages into liver, and improved the production of IFN-γ and IL-6 of splenocytes in ConA-induced hepatitis mice. SFP-100 and its two sugar fractions increased LO2 cell proliferation and reduced cell apoptosis induced by ConA. SFP-100, SFP-100-A and SFP-100-C remarkedly inhibited the secretion of HBsAg and HBeAg by HepG2.2.15 cells.These results suggested Sophora flavescens polysaccharides exerts significant hepatoprotective and anti-HBV roles, and further is used for treatment of immune-mediated liver disease in the future. Copyright © 2017. Published by Elsevier B.V.

Soil tension mediates isotope fractionation during soil water evaporation

NASA Astrophysics Data System (ADS)

Gaj, Marcel; McDonnell, Jeffrey

2017-04-01

Isotope tracing of the water cycle is increasing in its use and usefulness. Many new studies are extracting soil waters and relating these to streamflow, groundwater recharge and plant transpiration. Nevertheless, unlike isotope fractionation factors from open water bodies, soil water fractionation factors are poorly understood and until now, only empirically derived. In contrast to open water evaporation where temperature, humidity and vapor pressure gradient define fractionation (as codified in the well-known Craig and Gordon model), soil water evaporation includes additionally, fractionation by matrix effects. There is yet no physical explanation of kinetic and equilibrium fraction from soil water within the soil profile. Here we present a simple laboratory experiment with four admixtures of soil grain size (from sand to silt to clay). Oven-dried samples were spiked with water of known isotopic composition at different soil water contents. Soils were then stored in sealed bags and the headspace filled with dry air and allowed to equilibrate for 24hours. Isotopic analysis of the headspace vapor was done with a Los Gatos Inc. water vapor isotope analyzer. Soil water potential of subsamples were measured with a water potential meter. We show for the first time that soil tension controls isotope fractionation in the resident soil water. Below a Pf 3.5 the δ-values of 18O and 2H of the headspace vapor is more positive and increases with increasing soil water potential. Surprisingly, we find that the relationship between soil tension and equilibrium fractionation is independent of soil type. However, δ-values of each soil type plot along a distinct evaporation line. These results indicate that equilibrium fractionation is affected by soil tension in addition to temperature. Therefore, at high soil water tension (under dry conditions) equilibrium fractionation is not consistent with current empirical formulations that ignore these effects. These findings may have implications for plant water uptake studies since plant root water uptake imparts tension to extract water from the soil matrix. Since this is the same physical force as soil water potential, root water uptake at high soil water potential might cause fractionation of soil water. Our work is ongoing to examine these knock-on effects.

Methanogenic Pathway and Fraction of CH4 Oxidized in Paddy Fields: Seasonal Variation and Effect of Water Management in Winter Fallow Season

PubMed Central

Zhang, Guangbin; Liu, Gang; Zhang, Yi; Ma, Jing; Xu, Hua; Yagi, Kazuyuki

2013-01-01

A 2-year field and incubation experiment was conducted to investigate δ13C during the processes of CH4 emission from the fields subjected to two water managements (flooding and drainage) in the winter fallow season, and further to estimate relative contribution of acetate to total methanogenesis (Fac) and fraction of CH4 oxidized (Fox) based on the isotopic data. Compared with flooding, drainage generally caused CH4, either anaerobically or aerobically produced, depleted in 13C. There was no obvious difference between the two in transport fractionation factor (εtransport) and δ13C-value of emitted CH4. CH4 emission was negatively related to its δ13C-value in seasonal variation (P<0.01). Acetate-dependent methanogenesis in soil was dominant (60–70%) in the late season, while drainage decreased Fac-value by 5–10%. On roots however, CH4 was mostly produced through H2/CO2 reduction (60–100%) over the season. CH4 oxidation mainly occurred in the first half of the season and roughly 10–90% of the CH4 was oxidized in the rhizosphere. Drainage increased Fox-value by 5–15%, which is possibly attributed to a significant decrease in production while no simultaneous decrease in oxidation. Around 30–70% of the CH4 was oxidized at the soil-water interface when CH4 in pore water was released into floodwater, although the amount of CH4 oxidized therein might be negligible relative to that in the rhizosphere. CH4 oxidation was also more important in the first half of the season in lab conditions and about 5–50% of the CH4 was oxidized in soil while almost 100% on roots. Drainage decreased Fox-value on roots by 15% as their CH4 oxidation potential was highly reduced. The findings suggest that water management in the winter fallow season substantially affects Fac in the soil and Fox in the rhizosphere and roots rather than Fac on roots and Fox at the soil-water interface. PMID:24069259

Anti-plasmodial activity of Norcaesalpin D and extracts of four medicinal plants used traditionally for treatment of malaria.

PubMed

Nondo, Ramadhani Selemani Omari; Moshi, Mainen Julius; Erasto, Paul; Masimba, Pax Jessey; Machumi, Francis; Kidukuli, Abdul Waziri; Heydenreich, Matthias; Zofou, Denis

2017-03-24

Malaria is an old life-threatening parasitic disease that is still affecting many people, mainly children living in sub-Saharan Africa. Availability of effective antimalarial drugs played a significant role in the treatment and control of malaria. However, recent information on the emergence of P. falciparum parasites resistant to one of the artemisinin-based combination therapies suggests the need for discovery of new drug molecules. Therefore, this study aimed to evaluate the antiplasmodial activity of extracts, fractions and isolated compound from medicinal plants traditionally used in the treatment of malaria in Tanzania. Dry powdered plant materials were extracted by cold macerations using different solvents. Norcaesalpin D was isolated by column chromatography from dichloromethane root extract of Caesalpinia bonducella and its structure was assigned based on the spectral data. Crude extracts, fractions and isolated compound were evaluated for antiplasmodial activity against chloroquine-sensitive P. falciparum (3D7), chloroquine-resistant P. falciparum (Dd2, K1) and artemisinin-resistant P. falciparum (IPC 5202 Battambang, IPC 4912 Mondolkiri) strains using the parasite lactate dehydrogenase assay. The results indicated that extracts of Erythrina schliebenii, Holarrhena pubescens, Dissotis melleri and C. bonducella exhibited antiplasmodial activity against Dd2 parasites. Ethanolic root extract of E. schliebenii had an IC 50 of 1.87 μg/mL while methanolic and ethanolic root extracts of H. pubescens exhibited an IC 50  = 2.05 μg/mL and IC 50  = 2.43 μg/mL, respectively. Fractions from H. pubescens and C. bonducella roots were found to be highly active against K1, Dd2 and artemisinin-resistant parasites. Norcaesalpin D from C. bonducella root extract was active with IC 50 of 0.98, 1.85 and 2.13 μg/mL against 3D7, Dd2 and IPC 4912-Mondolkiri parasites, respectively. Antiplasmodial activity of norcaesalpin D and extracts of E. schliebenii, H. pubescens, D. melleri and C. bonducella reported in this study requires further attention for the discovery of antimalarial lead compounds for future drug development.

Suberin-derived aliphatic monomers as biomarkers for SOM affected by root litter contribution

NASA Astrophysics Data System (ADS)

Kogel-Knabner, I.; Spielvogel, S.-; Prietzel, J.-

2012-12-01

The patchy distribution of trees and ground vegetation may have major impact on SOC variability and stability at the small scale. Knowledge about correlations between the pattern of tree and ground vegetation, SOC stocks in different soil depths and the contribution of root- vs. shoot-derived carbon to different SOC fractions is scarce. We have tested analysis of hydrolysable aliphatic monomers derived from the biopolyesters cutin- and suberin to investigate whether their composition can be traced back after decay and transformation into soil organic matter (SOM) to study SOM source, degradation, and stand history. The main objective of this study was to elucidate the relative abundance of cutin and suberin in different particle size and density fractions of a Norway spruce and a European beech site with increasing distance to stems. Soil samples, root, bark and needle/leave samples were analyzed for their cutin and/or suberin signature. Previous to isolation of bound lipids, sequential solvent extraction was used to remove free lipids and other solvent extractable compounds. Cutin- and suberin-derived monomers were extracted from the samples using base hydrolysis. Before analysis by Gas Chromatography/Mass Spectrometry (GC/MS), extracts were derivatized to convert compounds to trimethylsilyl derivatives. Statistical analysis identified four variables which as combined factors discriminated significantly between cutin and suberin based on their structural units. We found a relative enrichment of cutin and suberin contents in the occluded fraction at both sites that decreased with increasing distance to the trees. We conclude from our results that (i) patchy above- and belowground carbon input caused by heterogeneous distribution of trees and ground vegetation has major impact on SOC variability and stability at the small scale, (ii) tree species is an important factor influencing SOC heterogeneity at the stand scale due to pronounced differences in above- and belowground carbon input among the tree species and that (iii) forest conversion may substantially alter SOC stocks and spatial distribution. Suberin biomarkers can thus be used as indicators for the presence of root influence on SOM composition and for identifying root-affected soil compartments.

Grassland Degradation Alters Soil Carbon Turnover through Depth

NASA Astrophysics Data System (ADS)

Creamer, C.; Prober, S. M.; Chappell, A.; Farrell, M.; Baldock, J.

2015-12-01

Ecosystem degradation is widespread and changes in aboveground plant communities alter belowground soil processes. In Australia, grassy eucalyptus woodlands dominated by kangaroo grasses (Themeda trianda) were widely cleared during European settlement for agriculture, with only fragments remaining of this now threatened ecosystem. As remnant grassland fragments are used for livestock grazing, Themeda transitions through states of degradation, starting with red grasses (Bothriochloa spp) and then proceeding to less productive, increasingly degraded states dominated by either annual exotic weeds or native wallaby grasses (Rytidosperma spp) and spear grasses (Austrastipa spp). The aim of our experiment was to determine how soil organic matter dynamics (including erosion, root biomass, C storage and turnover) have been altered by the transition from deeply-rooted Themeda grass systems to more shallowly-rooted annual exotic weeds and wallaby/spear grass states. We sampled soils in five depth-based increments (0-5, 5-15, 15-30, 30-60, 60-100 cm) across this ecosystem transition at five sites across New South Wales, Australia. Caseium-137 analysis indicated erosion rates were similar among all ecosystems and were consistent with levels for grasslands in the region. Compared to the remnant Themeda grass systems, the degraded states had lower root biomass, lower carbon stocks and C:N ratios in the coarse fraction (> 50 μm), lower fungal : bacterial ratios, higher available phosphate, higher alkyl : O-alkyl C ratios, and faster mineralization of synthetic root-exudate carbon. All these metrics indicate the surprising finding of more microbially processed OM and faster turnover of newly added C in the degraded sites. Compared to one another, the two degraded sites differed in both C and N turnover, with the exotic weeds having higher dissolved organic N, inorganic N, and coarse fraction N, higher fine fraction C stocks, and greater microbial biomass. These differences likely arise from the greater aboveground productivity of exotic weeds relative to the wallaby and spear grasses. Although microbial C turnover through depth is altered with grassland degradation in both states, the trajectory of the soil organic matter dynamics with degradation is also impacted by plant community dynamics.

Experimental Evidence that Hemlock Mortality Enhances Carbon Stabilization in Southern Appalachian Forest Soils

NASA Astrophysics Data System (ADS)

Fraterrigo, J.; Ream, K.; Knoepp, J.

2017-12-01

Forest insects and pathogens (FIPs) can cause uncertain changes in forest carbon balance, potentially influencing global atmospheric carbon dioxide (CO2) concentrations. We quantified the effects of hemlock (Tsuga canadensis L. Carr.) mortality on soil carbon fluxes and pools for a decade following either girdling or natural infestation by hemlock woolly adelgid (HWA; Adelges tsugae) to improve mechanistic understanding of soil carbon cycling response to FIPs. Although soil respiration (Rsoil) was similar among reference plots and plots with hemlock mortality, both girdled and HWA-infested plots had greater activities of β-glucosidase, a cellulose-hydrolyzing extracellular enzyme, and decreased O-horizon mass and fine root biomass from 2005 to 2013. During this period, total mineral soil carbon accumulated at a higher rate in disturbed plots than in reference plots in both the surface (0-10 cm) and subsurface (10-30 cm); increases were predominantly in the mineral-associated fraction of the soil organic matter. In contrast, particulate organic matter carbon accrued slowly in surface soils and declined in the subsurface of girdled plots. δ13C values of this fraction demonstrate that particulate organic matter carbon in the surface soil has become more microbially processed over time, suggesting enhanced decomposition of organic matter in this pool. Together, these findings indicate that hemlock mortality and subsequent forest regrowth has led to enhanced soil carbon stabilization in southern Appalachian forests through the translocation of carbon from detritus and particulate soil organic matter pools to the mineral-associated organic matter pool. These findings have implications for ecosystem management and modeling, demonstrating that forests may tolerate moderate disturbance without diminishing soil carbon storage when there is a compensatory growth response by non-host trees.

Assessment of the SMAP Level-4 Surface and Root-Zone Soil Moisture Product Using In Situ Measurements

USDA-ARS?s Scientific Manuscript database

The Soil Moisture Active Passive (SMAP) mission Level-4 Surface and Root-Zone Soil Moisture (L4_SM) data product is generated by assimilating SMAP L-band brightness temperature observations into the NASA Catchment land surface model. The L4_SM product is available from 31 March 2015 to present (with...

HYDRAULIC REDISTRIBUTION OF SOIL WATER BY ROOTS IN FORESTS OF THE PACIFIC NORTHWEST

EPA Science Inventory

One aspect of structural complexity of forest canopies is the root system structure belowground, which influences patterns of soil water utilization by trees. Deeply rooted trees and other plants can hydraulically lift water via their roots from several m below the soil surface ...

UV-B Induced Generation of Reactive Oxygen Species Promotes Formation of BFA-Induced Compartments in Cells of Arabidopsis Root Apices

PubMed Central

Yokawa, Ken; Kagenishi, Tomoko; Baluška, František

2016-01-01

UV-B radiation is an important part of the electromagnetic spectrum emitted by the sun. For much of the period of biological evolution organisms have been exposed to UV radiation, and have developed diverse mechanisms to cope with this potential stress factor. Roots are usually shielded from exposure to UV by the surrounding soil, but may nevertheless be exposed to high energy radiation on the soil surface. Due to their high sensitivity to UV-B radiation, plant roots need to respond rapidly in order to minimize exposure on the surface. In addition to root gravitropism, effective light perception by roots has recently been discovered to be essential for triggering negative root phototropism in Arabidopsis. However, it is not fully understood how UV-B affects root growth and phototropism. Here, we report that UV-B induces rapid generation of reactive oxygen species which in turn promotes the formation of BFA-induced compartments in the Arabidopsis root apex. During unilateral UV-B irradiation of roots changes in auxin concentration on the illuminated side have been recorded. In conclusion, UV-B-induced and ROS-mediated stimulation of vesicle recycling promotes root growth and induces negative phototropism. PMID:26793199

Dietary corn fractions reduce atherogenesis in low-density lipoprotein receptor knockout mice.

PubMed

Masisi, Kabo; Le, Khuong; Ghazzawi, Nora; Moghadasian, Mohammed H; Beta, Trust

2017-01-01

Accumulating evidence has suggested that intake of whole grains is a protective factor against pathogenesis of coronary artery disease. The exact mechanisms, however, are still not clearly understood. In this study, we hypothesized that adequate intake of corn fractions (aleurone, endosperm and germ) can modify lipid profiles in relation to atherosclerotic lesion development in low-density lipoprotein receptor knockout (LDLr-KO) mice. The purpose of the present study was to investigate the potential cardiovascular benefits of corn fractions in LDLr-KO mice through a number of biomarkers including lipid profile, and morphologic and morphometrical analysis of atherosclerotic lesions in aortic root. Four groups of male LDLr-KO mice were fed with the experimental diets supplemented with (3 treated) or without (control) 5% (wt/wt) of each of corn fractions for 10 weeks. All diets were supplemented with 0.06% (wt/wt) cholesterol. Compared with mice in the control group, atherosclerotic lesions in the aortic roots were significantly reduced (P=.003) in the mice that were fed diet supplemented with aleurone and germ fractions. This effect was associated with significant reductions in plasma total (P=.02) and LDL (P=.03) cholesterol levels, and an increase in fecal cholesterol excretion (P=.04). Furthermore, abdominal fat mass was significantly reduced by consumption of aleurone (P=.03). In summary, the consumption of aleurone and germ may help attenuate atherosclerosis by reducing plasma total and LDL cholesterol levels. Copyright © 2016 Elsevier Inc. All rights reserved.

Changes in lumbosacral spinal nerve roots on diffusion tensor imaging in spinal stenosis.

PubMed

Hou, Zhong-Jun; Huang, Yong; Fan, Zi-Wen; Li, Xin-Chun; Cao, Bing-Yi

2015-11-01

Lumbosacral degenerative disc disease is a common cause of lower back and leg pain. Conventional T1-weighted imaging (T1WI) and T2-weighted imaging (T2WI) scans are commonly used to image spinal cord degeneration. However, these modalities are unable to image the entire lumbosacral spinal nerve roots. Thus, in the present study, we assessed the potential of diffusion tensor imaging (DTI) for quantitative assessment of compressed lumbosacral spinal nerve roots. Subjects were 20 young healthy volunteers and 31 patients with lumbosacral stenosis. T2WI showed that the residual dural sac area was less than two-thirds that of the corresponding normal area in patients from L3 to S1 stenosis. On T1WI and T2WI, 74 lumbosacral spinal nerve roots from 31 patients showed compression changes. DTI showed thinning and distortion in 36 lumbosacral spinal nerve roots (49%) and abruption in 17 lumbosacral spinal nerve roots (23%). Moreover, fractional anisotropy values were reduced in the lumbosacral spinal nerve roots of patients with lumbosacral stenosis. These findings suggest that DTI can objectively and quantitatively evaluate the severity of lumbosacral spinal nerve root compression.

Plant-Sediment Interactions in Salt Marshes - An Optode Imaging Study of O2, pH, and CO 2 Gradients in the Rhizosphere.

PubMed

Koop-Jakobsen, Ketil; Mueller, Peter; Meier, Robert J; Liebsch, Gregor; Jensen, Kai

2018-01-01

In many wetland plants, belowground transport of O 2 via aerenchyma tissue and subsequent O 2 loss across root surfaces generates small oxic root zones at depth in the rhizosphere with important consequences for carbon and nutrient cycling. This study demonstrates how roots of the intertidal salt-marsh plant Spartina anglica affect not only O 2 , but also pH and CO 2 dynamics, resulting in distinct gradients of O 2 , pH, and CO 2 in the rhizosphere. A novel planar optode system (VisiSens TD ® , PreSens GmbH) was used for taking high-resolution 2D-images of the O 2 , pH, and CO 2 distribution around roots during alternating light-dark cycles. Belowground sediment oxygenation was detected in the immediate vicinity of the roots, resulting in oxic root zones with a 1.7 mm radius from the root surface. CO 2 accumulated around the roots, reaching a concentration up to threefold higher than the background concentration, and generally affected a larger area within a radius of 12.6 mm from the root surface. This contributed to a lowering of pH by 0.6 units around the roots. The O 2 , pH, and CO 2 distribution was recorded on the same individual roots over diurnal light cycles in order to investigate the interlinkage between sediment oxygenation and CO 2 and pH patterns. In the rhizosphere, oxic root zones showed higher oxygen concentrations during illumination of the aboveground biomass. In darkness, intraspecific differences were observed, where some plants maintained oxic root zones in darkness, while others did not. However, the temporal variation in sediment oxygenation was not reflected in the temporal variations of pH and CO 2 around the roots, which were unaffected by changing light conditions at all times. This demonstrates that plant-mediated sediment oxygenation fueling microbial decomposition and chemical oxidation has limited impact on the dynamics of pH and CO 2 in S. anglica rhizospheres, which may in turn be controlled by other processes such as root respiration and root exudation.

Fine root biomass in relation to site and stand characteristics in Norway spruce and Scots pine stands.

PubMed

Helmisaari, Heljä-Sisko; Derome, John; Nöjd, Pekka; Kukkola, Mikko

2007-10-01

Variations in fine root biomass of trees and understory in 16 stands throughout Finland were examined and relationships to site and stand characteristics determined. Norway spruce fine root biomass varied between 184 and 370 g m(-2), and that of Scots pine ranged between 149 and 386 g m(-2). In northern Finland, understory roots and rhizomes (< 2 mm diameter) accounted for up to 50% of the stand total fine root biomass. Therefore, the fine root biomass of trees plus understory was larger in northern Finland in stands of both tree species, resulting in a negative relationship between fine root biomass and the temperature sum and a positive relationship between fine root biomass and the carbon:nitrogen ratio of the soil organic layer. The foliage:fine root ratio varied between 2.1 and 6.4 for Norway spruce and between 0.8 and 2.2 for Scots pine. The ratio decreased for both Norway spruce and Scots pine from south to north, as well as from fertile to more infertile site types. The foliage:fine root ratio of Norway spruce was related to basal area and stem surface area. The strong positive correlations of these three parameters with fine root nitrogen concentration implies that more fine roots are needed to maintain a certain amount of foliage when nutrient availability is low. No significant relationships were found between stand parameters and fine root biomass at the stand level, but the relationships considerably improved when both fine root biomass and stand parameters were calculated for the mean tree in the stand. When the northern and southern sites were analyzed separately, fine root biomass per tree of both species was significantly correlated with basal area and stem surface area per tree. Basal area, stem surface area and stand density can be estimated accurately and easily. Thus, our results may have value in predicting fine root biomass at the tree and stand level in boreal Norway spruce and Scots pine forests.

Effect of two storage solutions on surface topography of two root-end fillings.

PubMed

Asgary, Saeed; Eghbal, Mohammad Jafar; Parirokh, Masoud; Ghoddusi, Jamileh

2009-12-01

The effect of different storage solutions on surface topography of mineral trioxide aggregate (MTA) and new experimental cement (NEC) as root-end fillings was investigated. Twenty-four single-rooted teeth were cleaned, shaped and obturated in a same manner. After root-end resection, 3-mm deep root-end cavities were ultrasonically prepared. Samples were randomly divided into four test groups (A1-A2-B1-B2, n = 6). Root-end cavities in groups A and B were filled with MTA and NEC, respectively, and were then stored in 100% humidity for 24 h. The samples of groups 1 and 2 were, respectively, immersed in normal saline (NS) and phosphate buffer saline solutions for 1 week. The samples were imaged under stereomicroscope before and after immersion and were then investigated and analysed by scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDXA). Results showed significant difference among studied groups. Surface topography of all samples was altered by crystal formation and precipitation on root-end fillings except for group A1 (MTA-NS). SEM and EDXA results showed that the composition and structure of precipitated crystals were comparable with that of standard hydroxyapatite. It was concluded that biocompatibility, sealing ability, and cementogenic activity of MTA and probably NEC may be attributed to this fundamental bioactive reaction.

Effect of bisphosphonates on root resorption after tooth replantation - a systematic review.

PubMed

Najeeb, Shariq; Siddiqui, Fahad; Khurshid, Zohaib; Zohaib, Sana; Zafar, Muhammad Sohail; Ansari, Shazia Akbar

2017-04-01

Replantation of avulsed teeth may lead to root resorption. Bisphosphonates (BPs), a class of drugs of used to treat resorptive diseases of the bone such as osteoporosis and Paget's disease, have been observed to exert an antiresorptive effect on periodontal bone as well. The antiresorptive properties of BPs could prove them useful in preventing root resorption of replanted avulsed teeth. The aim of this systematic review was to analyze and summarize the currently available literature concerning the use of BPs in preventing root resorption of avulsed teeth. PubMed/MEDLINE, Google Scholar, ISI Web of Knowledge, and Embase databases were searched using keywords 'bisphosphonate', 'replantation', and 'tooth'. Quality assessment of each study was carried out. In addition, general characteristics and outcomes of each study were summarized. After exclusion of 116 irrelevant articles, 10 animal studies were included in this review. The majority of the studies suggest that surface application of zoledronate or alendronate reduces root resorption of replanted teeth in animal models. Surface treatment with etidronate had no significant effect on root resorption, and intracanal etidronate accelerated resorption. Surface application of zoledronate and alendronate reduces root resorption of replanted teeth in animal models. However, the efficacy of intracanal usage of BPs is still debatable. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Slow decomposition of lower order roots: a key mechanism of root carbon and nutrient retention in the soil.

PubMed

Fan, Pingping; Guo, Dali

2010-06-01

Among tree fine roots, the distal small-diameter lateral branches comprising first- and second-order roots lack secondary (wood) development. Therefore, these roots are expected to decompose more rapidly than higher order woody roots. But this prediction has not been tested and may not be correct. Current evidence suggests that lower order roots may decompose more slowly than higher order roots in tree species associated with ectomycorrhizal (EM) fungi because they are preferentially colonized by fungi and encased by a fungal sheath rich in chitin (a recalcitrant compound). In trees associated with arbuscular mycorrhizal (AM) fungi, lower order roots do not form fungal sheaths, but they may have poorer C quality, e.g. lower concentrations of soluble carbohydrates and higher concentrations of acid-insolubles than higher order roots, thus may decompose more slowly. In addition, litter with high concentrations of acid insolubles decomposes more slowly under higher N concentrations (such as lower order roots). Therefore, we propose that in both AM and EM trees, lower order roots decompose more slowly than higher order roots due to the combination of poor C quality and high N concentrations. To test this hypothesis, we examined decomposition of the first six root orders in Fraxinus mandshurica (an AM species) and Larix gmelinii (an EM species) using litterbag method in northeastern China. We found that lower order roots of both species decomposed more slowly than higher order roots, and this pattern appears to be associated mainly with initial C quality and N concentrations. Because these lower order roots have short life spans and thus dominate root mortality, their slow decomposition implies that a substantial fraction of the stable soil organic matter pool is derived from these lower order roots, at least in the two species we studied.

Mechanism of formation of humus coatings on mineral surfaces 2. Attenuated total reflectance spectra of hydrophobic and hydrophilic fractions of organic acids from compost leachate on alumina

USGS Publications Warehouse

Wershaw, R. L.; Llaguno, E.C.; Leenheer, J.A.; Sperline, R.P.; Song, Y.

1996-01-01

Hydrophobic and hydrophilic fractions were isolated from a compost leachate. The adsorption isotherms of both fractions on alumina were measured by attenuated total reflectance infrared spectroscopy. The shapes of the adsorption isotherms of the two fractions were different. The isotherms for the hydrophilic fraction showed little change in surface excess with increasing solution concentration above 4 mg L-1. The isotherms for the hydrophobic fraction, on the other hand, displayed a marked increase in surface excess with increasing solution concentration. This increase is evidence for the formation of aggregates (admicelles or hemimicelles) on the alumina surface. Linear dichroism calculations indicated that more of the carboxylate groups in the adsorbed hydrophobic molecules than in the absorbed hydrophilic fraction were free to rotate. The hindered rotation of the carboxylate groups in the adsorbed hydrophilic-fraction molecules probably indicates that these groups are bound to surface aluminum ions by a bidentate mechanism in which the two oxygen atoms of a single carboxylate group bind to separate aluminum ions.

Chlorhexidine controlled-release profile after EDTA root surface etching: an in vivo study.

PubMed

Gamal, Ahmed Y; Kumper, Radi M; Sadek, Hesham S; El Destawy, Mahmoud T

2011-05-01

The main objective of the present study was to quantify chlorhexidine (CHX) release after the use of CHX-EDTA root surface treatment as a local-delivery antimicrobial vehicle. Twenty non-smoking patients clinically diagnosed as having moderate-to-severe chronic periodontitis were selected to participate in this study. After cause-related therapy, one site in every patient received defect overfill with CHX gel 2% (20 sites). In addition, twenty contralateral sites received defect fill of CHX gel after 3 minutes of 24% EDTA gel root surface etching (20 sites). Gingival crevicular fluid samples were collected at 1, 3, 7, and 14 days post-therapy. The CHX-EDTA group showed statistically significantly higher levels of CHX than those of the control group at 1, 3, and 7 days. At 14 days, the CHX-EDTA group showed 0.8 mg/mL values. The use of CHX-EDTA root surface treatment as a local-delivery antimicrobial improves CHX substantivity.

Physical properties of root cementum: Part 18. The extent of root resorption after the application of light and heavy controlled rotational orthodontic forces for 4 weeks: a microcomputed tomography study.

PubMed

Wu, Andy T J; Turk, Tamer; Colak, Canan; Elekdağ-Turk, Selma; Jones, Allan S; Petocz, Peter; Darendeliler, M Ali

2011-05-01

The aim of this prospective randomized clinical trial was to quantitatively measure and compare the locations, dimensions, and volume of root resorption craters in human premolars after the application of controlled light and heavy rotational orthodontic forces over a 28-day (4-week) period. Fifteen patients requiring bilateral extraction of maxillary first premolars as part of their orthodontic treatment were recruited for this study. Each patient received a heavy (225 g) rotational force on 1 premolar and a light (25 g) rotational force on the contralateral premolar. Orthodontic rotational forces were applied over 28 days with buccal and palatal cantilever springs; 0.016-inch beta-titanium molybdenum alloys were used to apply the light force and 0.018-inch stainless steel was used for the heavy force. After the 28-day experimental period, the upper first premolars were extracted under stringent protocols to prevent root surface damage. The samples were then scanned using a microcomputed tomography (micro-CT) scan x-ray system (SkyScan 1072, Skyscan, Aartselaar, Belgium), and analyzed using convex hull algorithm (CHULL2D; University of Sydney, Sydney, Australia) software to obtain direct volumetric measurements. The mean volume of resorption craters was 0.42 in the light force group and 0.51 in the heavy force group (P = 0.013). When separated at the root level, the difference in volume of root resorption craters between the 2 groups was significantly different only at the midlevel (P = 0.001). Root resorption craters were consistently detected at the boundaries between the buccal and distal surfaces and the mesial and lingual surfaces. The result supports our hypothesis that positive areas develop significantly more root resorption craters at all 3 levels, as compared with minimal areas (paired t test <0.001). Heavy rotational forces caused more root resorption than light rotational forces and compression areas (buccal-distal and lingual-mesial surfaces in this study) showed significantly higher root resorption than other areas at all levels of the root. Copyright © 2011 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.

Incidence and severity of root resorption in orthodontically moved premolars in dogs.

PubMed

Maltha, J C; van Leeuwen, E J; Dijkman, G E H M; Kuijpers-Jagtman, A M

2004-05-01

To study treatment-related factors for external root resorption during orthodontic tooth movement. An experimental animal study. Department of Orthodontics and Oral Biology, University Medical Centre Nijmegen, The Netherlands. Twenty-four young adult beagle dogs. Mandibular premolars were bodily moved with continuous or intermittent controlled orthodontic forces of 10, 25, 50, 100, or 200 cN according to standardized protocols. At different points in time histomorphometry was performed to determine the severity of root resorption. Prevalence of root resorptions, defined as microscopically visible resorption lacunae in the dentin. Severity of resorption was defined by the length, relative length, depth, and surface area of each resorption area. The incidence of root resorption increased with the duration of force application. After 14-17 weeks of force application root resorption was found at 94% of the root surfaces at pressure sides. The effect of force magnitude on the severity of root resorption was not statistically significant. The severity of root resorption was highly related to the force regimen. Continuous forces caused significantly more severe root resorption than intermittent forces. A strong correlation (0.60 < r < 0.68) was found between the amount of tooth movement and the severity of root resorption. Root resorption increases with the duration of force application. The more teeth are displaced, the more root resorption will occur. Intermittent forces cause less severe root resorption than continuous forces, and force magnitude is probably not decisive for root resorption.

Touch and gravitropic set-point angle interact to modulate gravitropic growth in roots

NASA Technical Reports Server (NTRS)

Massa, G. D.; Gilroy, S.

2003-01-01

Plant roots must sense and respond to a variety of environmental stimuli as they grow through the soil. Touch and gravity represent two of the mechanical signals that roots must integrate to elicit the appropriate root growth patterns and root system architecture. Obstacles such as rocks will impede the general downwardly directed gravitropic growth of the root system and so these soil features must be sensed and this information processed for an appropriate alteration in gravitropic growth to allow the root to avoid the obstruction. We show that primary and lateral roots of Arabidopsis do appear to sense and respond to mechanical barriers placed in their path of growth in a qualitatively similar fashion. Both types of roots exhibited a differential growth response upon contacting the obstacle that directed the main axis of elongation parallel to the barrier. This growth habit was maintained until the obstacle was circumvented, at which point normal gravitropic growth was resumed. Thus, the gravitational set-point angle of the primary and lateral roots prior to encountering the barrier were 95 degrees and 136 degrees respectively and after growing off the end of the obstacle identical set-point angles were reinstated. However, whilst tracking across the barrier, quantitative differences in response were observed between these two classes of roots. The root tip of the primary root maintained an angle of 136 degrees to the horizontal as it traversed the barrier whereas the lateral roots adopted an angle of 154 degrees. Thus, this root tip angle appeared dependent on the gravitropic set-point angle of the root type with the difference in tracking angle quantitatively reflecting differences in initial set-point angle. Concave and convex barriers were also used to analyze the response of the root to tracking along a continuously varying surface. The roots maintained the a fairly fixed angle to gravity on the curved surface implying a constant resetting of this tip angle/tracking response as the curve of the surface changed. We propose that the interaction of touch and gravity sensing/response systems combine to strictly control the tropic growth of the root. Such signal integration is likely a critical part of growth control in the stimulus-rich environment of the soil. c2003 COSPAR. Published by Elsevier Ltd. All rights reserved.

Immunohistochemical study of bone sialoprotein and osteopontin in healthy and diseased root surfaces.

PubMed

Lao, Martin; Marino, Victor; Bartold, P Mark

2006-10-01

Periodontal disease is marked by inflammation and damage to tooth-supporting tissues. In particular, damage occurs to factors present in cementum that are thought to have the ability to influence the regeneration of surrounding tissues. Bone sialoprotein and osteopontin are major non-collagenous proteins in mineralized connective tissues associated with precementoblast chemo-attraction, adhesion to the root surface, and cell differentiation. The purpose of this investigation was to determine whether the expression and distribution of bone sialoprotein and osteopontin on root surfaces affected by periodontitis are altered compared to healthy, non-diseased root surfaces. Thirty healthy and 30 periodontitis-affected teeth were collected. Following fixation and demineralization, specimens were embedded in paraffin, sectioned, and exposed to antibodies against bone sialoprotein and osteopontin. Stained sections were assessed using light microscopy. Bone sialoprotein was not detected in the exposed cementum (absence of overlying periodontal ligament) of diseased teeth. In most areas where the periodontal ligament was intact, bone sialoprotein was detected for healthy and diseased teeth. For teeth reactive for bone sialoprotein, the matrix of the cementum just below the periodontal ligament was moderately stained. A similar immunoreactivity pattern for osteopontin was observed. The absence of bone sialoprotein and osteopontin staining along exposed cementum surfaces may be due to structural and compositional changes in matrix components associated with periodontal disease. This may influence the ability for regeneration and new connective tissue attachment onto previously diseased root surfaces.

Micro-computed tomography evaluation of the preparation of long oval root canals in mandibular molars with the self-adjusting file.

PubMed

Paqué, Frank; Peters, Ove A

2011-04-01

The aim of this study was to assess the shaping potential of a novel nickel-titanium instrument, the self-adjusting file (SAF), in long oval root canals in distal roots in mandibular molars. Twenty mandibular molars with long oval distal root canals were selected and scanned preoperatively and postoperatively by using micro-computed tomography at an original resolution of 20 μm. Canals were shaped with the SAF, three-dimensionally reconstructed, and evaluated for volume, surface area, canal transportation, and prepared surface. Data were statistically contrasted by using paired t tests and regression analysis. Preoperatively, canal volume was 7.73 ± 2.13 mm(3), and canal area was 42.83 ± 8.14 mm(2). Volumes and surface areas increased significantly (P < .001) by 4.84 ± 1.73 mm(3) and 3.34 ± 1.73 mm(2), respectively, and no gross preparation errors were detected. Unprepared canal surface varied between individual canals, and mean unprepared surface was 23.5% ± 8.9%. Prepared areas were significantly larger compared with rotary canal preparation done in a previous study. Canal transportation scores were higher in the coronal root canal third (106 ± 50 μm) compared with the apical third (81 ± 49 μm). In vitro, preparation of long oval-shaped root canals in mandibular molars with the SAF was effective and safe. Moreover, shapes generated with the SAF were more complete compared with rotary canal preparation. Copyright © 2011 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Evaluation of Blood Cell Attachment on Er:Yag Laser Applied Root Surface Using Scanning Electron Microscopy

PubMed Central

CEKICI, Ali; MADEN, Ilay; YILDIZ, Sercan; SAN, Tangul; ISIK, Gulden

2013-01-01

Background: Periodontal regeneration is dependent on the uninterrupted adhesion, maturation and absorption of fibrin clots to a periodontally compromised root surface. The modification of the root surface with different agents has been used for better fibrin clot formation and blood cell attachment. It is known that Er:YAG laser application on dentin removes the smear layer succesfully. Aim: The aim of this study is to observe blood cell attachment and fibrin network formation following ER:YAG laser irradiation on periodontally compromised root surfaces in comparison to chemical root conditioning techniques in vitro. Materials and methods: 40 dentin blocks prepared from freshly extracted periodontally compromised hopeless teeth. Specimens were divided in 5 groups; those applied with PBS, EDTA, Citric acid and Er:YAG. They were further divided into two groups: those which had received these applications, and the control group. The specimens were evaluated with scanning electron microscope and micrographs were taken. Smear layer and blood cell attachment scoring was performed. Results: In the Er:YAG laser applied group, smear layer were totally removed. In the blood applied specimens, better fibrin clot formation and blood cell attachment were observed in the Er:YAG group. In the group that had been applied with citric acid, the smear layer was also removed. The smear layer could not be fully removed in the EDTA group. Conclusion: Er:YAG laser application on the root dentin seems to form a suitable surface for fibrin clot formation and blood cell attachment. Further clinical studies to support these results are necessitated. PMID:23533017

Amphibole Fractional Crystallization and Delamination in Arc Roots: Implications for the `Missing' Nb Reservoir in the Earth

NASA Astrophysics Data System (ADS)

Galster, F.; Chatterjee, R. N.; Stockli, D. F.

2017-12-01

Most geologic processes should not fractionate Nb from Ta but Earth's major silicate reservoirs have subchondritic Nb/Ta values. Nb/Ta of >10000 basalts and basaltic andesites from different tectonic settings (GEOROC) cluster around 16, indistinguishable from upper mantle values. In contrast, Nb/Ta in more evolved arc volcanics have progressively lower values, reaching continental crust estimates, and correlate negatively with SiO2 (see figure) and positively with TiO2 and MgO. This global trend suggests that differentiation processes in magmatic arcs could explain bulk crustal Nb/Ta estimates. Understanding processes that govern fractionation of Nb from Ta in arcs can provide key insights on continental crust formation and help identify Earth's `missing' Nb reservoir. Ti-rich phases (rutile, titanite and ilmenite) have DNb/DTa <1, and therefore, their fractionation from mafic to intermediate liquids cannot explain the observed trend. Instead, fractionation of biotite and amphibole could lower Nb/Ta values in the evolved liquid. Lack of correlation between Nb/Ta and K2O in global volcanic rocks implies that biotite plays a minor role in fractionating Nb from Ta during differentiation. Experimental petrology and evidence from exposed arc sections indicate that amphibole fractionation and delamination of island arc roots can explain the andesitic composition of bulk continental crust. Experimental studies have shown that amphibole Mg# correlate with DNb/DTa and amphibole could effectively fractionate Nb from Ta. Preliminary data from lower to middle crustal amphiboles from preserved arcs show sub- to super-chondritic Nb/Ta up to >60. This suggests that delamination of amphibole-rich cumulates can be a viable mechanism for the preferential removal of Nb from the continental crust. Future examination of Nb/Ta ratios in lower crustal amphiboles from various preserved arcs will provide improved constraints on the Nb-Ta paradox of the silicate Earth.

[Microbial Community Structure on the Root Surface of Patients with Periodontitis.

PubMed

Zhang, Ju-Mei; Zhou, Jian-Ye; Bo, Lei; Hu, Xiao-Pan; Jiao, Kang-Li; Li, Zhi-Jie; Li, Yue-Hong; Li, Zhi-Qiang

2016-11-01

To study the microbial community structure on the root surface of patients with periodontitis. Bacterial plaque and tissues from the root neck (RN group),root middle (RM group) and root tine (RT group) of six teeth with mobility 3 in one patient with periodontitis were sampled.The V3V4 region of 16S rRNA was sequenced on the Illumina MiSeq platform.The microbial community structure was analyzed by Mothur,Qiime and SPSS software. The principal component analysis (PCoA) results indicated that the RM samples had a similar microbial community structure as that of the RT samples,which was significant different from that of the RN samples.Thirteen phyla were detected in the three groups of samples,which included 7 dominant phyla.29 dominant genera were detected in 184 genera.The abundance of Bacteroidetes _[G-6] and Peptostre ptococcaceae _[XI][G-4] had a positive correlation with the depth of the collection site of samples ( P <0.05),while the abundance of Prevotella,Selenomonas,Corynebacterium and Olsenella had a negative correlation with the depth of the collection site of samples ( P <0.05). There is region-specificity of microbial community structure on the root surface of patients with periodontitis.

Ontogeny of Daucus carota Infected with Meloidogyne hapla

PubMed Central

Slinger, L. A.; Bird, G. W.

1978-01-01

The ontogeny of carrots (Daucus carota cv. 'Spartan Premium') grown under greenhouse conditions in pots of organic soil infected with Meloidogyne hapla was influenced detrimentally as early as 4 days after seeding, as determined through analysis of plant surface area, dry weight, fresh weight, net assimilation rate, relative growth rate, and leaf-area ratio. Only 58% of the diseased carrots were suitable for fresh market, compared with 97% of those grown in nematode-free soil. Growth and development of the shoot system (height, surface area, dry weight, and fresh weight) were retarded by M. hapla as early as 12 days after seeding. During the first 12 days after seeding, root dry weight was greater for diseased plants than for controls. Root growth and development (surface area, dry weight, and fresh weight) associated with this nematode, however, were retarded as early as 16 days after seeding. M. hapla caused a delay in the occurrence of 2nd-, 4th-, and 5th-order roots, and an increase in the occurrence of 6th-order roots in infected plants. Parasitized plants had 44% fewer roots (primary through 6th-order) and 50% less total root length. PMID:19305837

Mutations in Arabidopsis thaliana genes involved in the tryptophan biosynthesis pathway affect root waving on tilted agar surfaces

NASA Technical Reports Server (NTRS)

Rutherford, R.; Gallois, P.; Masson, P. H.

1998-01-01

Arabidopsis thaliana roots grow in a wavy pattern upon a slanted surface. A novel mutation in the anthranilate synthase alpha 1 (ASA1) gene, named trp5-2wvc1, and mutations in the tryptophan synthase alpha and beta 1 genes (trp3-1 and trp2-1, respectively) confer a compressed root wave phenotype on tilted agar surfaces. When trp5-2wvc1 seedlings are grown on media supplemented with anthranilate metabolites, their roots wave like wild type. Genetic and pharmacological experiments argue that the compressed root wave phenotypes of trp5-2wvc1, trp2-1 and trp3-1 seedlings are not due to reduced IAA biosynthetic potential, but rather to a deficiency in L-tryptophan (L-Trp), or in a L-Trp derivative. Although the roots of 7-day-old seedlings possess higher concentrations of free L-Trp than the shoot as a whole, trp5-2wvc1 mutants show no detectable alteration in L-Trp levels in either tissue type, suggesting that a very localized shortage of L-Trp, or of a L-Trp-derived compound, is responsible for the observed phenotype.

In vitro evaluation of the temperature increment at the external root surface after Er,Cr:YSGG laser irradiation of the root canal.

PubMed

Abad-Gallegos, M; Arnabat-Domínguez, J; España-Tost, A; Berini-Aytés, L; Gay-Escoda, C

2009-12-01

A study was made to determine the temperature increment at the dental root surface following Er,Cr:YSGG laser irradiation of the root canal. Human canines and incisors previously instrumented to K file number ISO 30 were used. Irradiation was carried out with glass fiber endodontic tips measuring 200 mm in diameter and especially designed for insertion in the root canal. The teeth were irradiated at 1 and 2 W for 30 seconds, without water spraying or air, and applying a continuous circular movement (approximately 2 mm/sec.) in the apico-coronal direction. At the 1 W power setting, the mean temperature increment was 3.84 degrees C versus 5.01 degrees C at 2 W. In all cases the difference in mean value obtained after irradiation versus the mean baseline temperature proved statistically significant (p<0.05). Application of the Er,Cr:YSGG laser gives rise to a statistically significant temperature increment at the external root surface, though this increment is probably clinically irrelevant, since it would appear to damage the tissues (periodontal ligament and alveolar bone) in proximity to the treated tooth.

Elevation of NO production increases Fe immobilization in the Fe-deficiency roots apoplast by decreasing pectin methylation of cell wall

PubMed Central

Ye, Yi Quan; Jin, Chong Wei; Fan, Shi Kai; Mao, Qian Qian; Sun, Cheng Liang; Yu, Yan; Lin, Xian Yong

2015-01-01

Cell wall is the major component of root apoplast which is the main reservoir for iron in roots, while nitric oxide (NO) is involved in regulating the synthesis of cell wall. However, whether such regulation could influence the reutilization of iron stored in root apoplast remains unclear. In this study, we observed that iron deficiency elevated NO level in tomato (Solanum lycopersicum) roots. However, application of S-nitrosoglutathione, a NO donor, significantly enhanced iron retention in root apoplast of iron-deficient plants, accompanied with a decrease of iron level in xylem sap. Consequently, S-nitrosoglutathione treatment increased iron concentration in roots, but decreased it in shoots. The opposite was true for the NO scavenging treatment with 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (cPTIO). Interestingly, S-nitrosoglutathione treatment increased pectin methylesterase activity and decreased degree of pectin methylation in root cell wall of both iron-deficient and iron-sufficient plants, which led to an increased iron retention in pectin fraction, thus increasing the binding capacity of iron to the extracted cell wall. Altogether, these results suggested that iron-deficiency-induced elevation of NO increases iron immobilization in root apoplast by decreasing pectin methylation in cell wall. PMID:26073914

Soybean Roots Grown under Heat Stress Show Global Changes in Their Transcriptional and Proteomic Profiles

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

Valdés-López, Oswaldo; Batek, Josef; Gomez-Hernandez, Nicolas

2016-04-25

Heat stress is likely to be a key factor in the negative impact of climate change on crop production. Roots provide support, water and nutrients to other plant organs. Likewise, roots play an important role in the establishment of symbiotic associations with different microorganisms. Despite the physiological relevance of roots, few studies have examined the response of these plant organs to heat stress. In this study, we performed genome-wide transcriptomic and proteomic analyses on isolated root hairs, which are a single, epidermal cell type, and compared their response to whole roots. We identified 2,013 genes differentially regulated in root hairsmore » in response to heat stress. Our gene regulatory module analysis identified ten, key modules that controlled the majority of the transcriptional response to heat stress. We also conducted proteomic analysis on membrane fractions isolated from roots and root hairs. These experiments identified a variety of proteins whose expression changed within 3 hours of application of heat stress. Most of these proteins were predicted to play a role in thermotolerance, as well as in chromatin remodeling and post-transcriptional regulation. The data presented represent an in-depth analysis of the heat stress response of a single cell type in soybean.« less

Desirable plant root traits for protecting unstable slopes against landslides

NASA Astrophysics Data System (ADS)

Stokes, A.; Atger, C.; Bengough, G.; Fourcaud, T.; Sidle, R. C.

2009-04-01

A trait is defined as a distinct, quantitative property of organisms, usually measured at the individual level and used comparatively across species. Plant quantitative traits are extremely important for understanding the local ecology of any site. Plant height, architecture, root depth, wood density, leaf size and leaf nitrogen concentration control ecosystem processes and define habitat for other taxa. An engineer conjecturing as to how plant traits may directly influence physical processes occurring on sloping land just needs to consider how e.g. canopy architecture and litter properties influence the partitioning of rainfall among interception loss, infiltration and runoff. Plant traits not only influence abiotic processes occurring at a site, but also the habitat for animals and invertebrates. Depending on the goal of the landslide engineer, the immediate and long-term effects of plant traits in an environment must be considered if a site is to remain viable and ecologically successful. When vegetation is considered in models of slope stability, usually the only root parameters taken into consideration are tensile strength and root area ratio. Root system spatial structure is not considered, although the length, orientation and diameter of roots are recognized as being of importance. Thick roots act like soil nails on slopes, reinforcing soil in the same way that concrete is reinforced with steel rods. The spatial position of these thick roots also has an indirect effect on soil fixation in that the location of thin and fine roots will depend on the arrangement of thick roots. Thin and fine roots act in tension during failure on slopes and if they cross the slip surface, are largely responsible for reinforcing soil on slopes. Therefore, the most important trait to consider initially is rooting depth. To stabilize a slope against a shallow landslide, roots must cross the shear surface. The number and thickness of roots in this zone will therefore largely determine slope stability. Rooting depth is species dependent when soil conditions are not limiting and the number of horizontal lateral roots borne on the vertical roots usually changes with depth. Therefore, the number and orientation of roots that the shear surface intersects will change significantly with rooting depth for the same plant, even for magnitudes of only several cm. Similarly, depending on the geometry of the root system, the angle at which a root crosses the shear surface can also have an influence on its resistance to pullout and breakage. The angle at which a root emerges from the parent root is dependent on root type, depth and species (when soil conditions are not limiting). Due to the physiology of roots, a root branch can be initiated at any point along a parent root, but not necessarily emerge fully from the parent root. These traits, along with others including size, relative growth rate, regeneration strategies, wood structure and strength will be discussed with regard to their influence on slope stability. How each of these traits is influenced by soil conditions and plantation techniques is also of extreme importance to the landslide engineer. The presence of obstacles in the soil, as well as compaction, affects root length and branching pattern. Roots of many species of woody plants on shallow soils also tend to grow along fractures deep into the underlying bedrock which allows roots to locate supplies of nutrient and water rich pockets. Rooting depths of herbaceous species in water-limited environments are highly correlated with infiltration depth, but waterlogged soils can asphyxiate tree roots, resulting in shallow root systems. The need to understand and integrate each of these traits for a species is not easy. Therefore, we suggest a hierarchy whereby traits are considered in order of importance, along with how external factors influence their expression over time.

Prediction of Root Zone Soil Moisture using Remote Sensing Products and In-Situ Observation under Climate Change Scenario

NASA Astrophysics Data System (ADS)

Singh, G.; Panda, R. K.; Mohanty, B.

2015-12-01

Prediction of root zone soil moisture status at field level is vital for developing efficient agricultural water management schemes. In this study, root zone soil moisture was estimated across the Rana watershed in Eastern India, by assimilation of near-surface soil moisture estimate from SMOS satellite into a physically-based Soil-Water-Atmosphere-Plant (SWAP) model. An ensemble Kalman filter (EnKF) technique coupled with SWAP model was used for assimilating the satellite soil moisture observation at different spatial scales. The universal triangle concept and artificial intelligence techniques were applied to disaggregate the SMOS satellite monitored near-surface soil moisture at a 40 km resolution to finer scale (1 km resolution), using higher spatial resolution of MODIS derived vegetation indices (NDVI) and land surface temperature (Ts). The disaggregated surface soil moisture were compared to ground-based measurements in diverse landscape using portable impedance probe and gravimetric samples. Simulated root zone soil moisture were compared with continuous soil moisture profile measurements at three monitoring stations. In addition, the impact of projected climate change on root zone soil moisture were also evaluated. The climate change projections of rainfall were analyzed for the Rana watershed from statistically downscaled Global Circulation Models (GCMs). The long-term root zone soil moisture dynamics were estimated by including a rainfall generator of likely scenarios. The predicted long term root zone soil moisture status at finer scale can help in developing efficient agricultural water management schemes to increase crop production, which lead to enhance the water use efficiency.

Effect of land use change on the carbon cycle in Amazon soils

NASA Technical Reports Server (NTRS)

Trumbore, Susan E.; Davidson, Eric A.

1994-01-01

The overall goal of this study was to provide a quantitative understanding of the cycling of carbon in the soils associated with deep-rooting Amazon forests. In particular, we wished to apply the understanding gained by answering two questions: (1) what changes will accompany the major land use change in this region, the conversion of forest to pasture? and (2) what is the role of carbon stored deeper than one meter in depth in these soils? To construct carbon budgets for pasture and forest soils we combined the following: measurements of carbon stocks in above-ground vegetation, root biomass, detritus, and soil organic matter; rates of carbon inputs to soil and detrital layers using litterfall collection and sequential coring to estimate fine root turnover; C-14 analyses of fractionated SOM and soil CO2 to estimate residence times; C-13 analyses to estimate C inputs to pasture soils from C-4 grasses; soil pCO2, volumetric water content, and radon gradients to estimate CO2 production as a function of soil depth; soil respiration to estimate total C outputs; and a model of soil C dynamics that defines SOM fractions cycling on annual, decadal, and millennial time scales.

A new validated HPTLC method for quantitative determination of 1, 5-dicaffeoylquinic acid in Inula crithmoides roots.

PubMed

Aboul-Ela, Maha Ahmed; El-Lakany, Abdalla Mohamed; Shams Eldin, Safa Mohamed; Hammoda, Hala Mostafa

2012-10-01

1, 5-Dicaffeoylquinic acid (1, 5-DCQA), a potent HIV-1 integrase inhibitor, is currently undergoing an evaluation as a promising novel HIV therapeutic agent. This work aims at developing an accurate, rapid, repeatable and robust HPTLC method for the determination of 1, 5-DCQA in its natural sources. 1, 5-DCQA is the major component of the n-butanol fraction, the most biologically active hepatoprotective fraction, of Inula crithmoides roots extract. Thus, it will be of interest to evaluate the plant roots as a potential source of 1, 5-DCQA using a fully validated HPTLC method. The percentage of 1, 5-DCQA in the studied plant (0.035% w/w) was found to be approximately similar to those previously determined in other antioxidant herbal drugs, in which 1, 5- DCQA is the main phenolic constituent. The results obtained showed that the described HPTLC method is suitable for routine use in quality control of herbal raw material, extracts and pharmaceutical preparations containing 1, 5-DCQA. No HPTLC method has been reported in literature for the determination of 1, 5-DCQA in medicinal plants.

Binding of isolated plant lectin by rhizobia during episodes of reduced gravity obtained by parabolic flight

NASA Technical Reports Server (NTRS)

Henry, R. L.; Green, P. D.; Wong, P. P.; Guikema, J. A.; Spooner, B. S. (Principal Investigator)

1990-01-01

Development of a legume root nodule is a complex process culminating in a plant/bacterial symbiosis possessing the capacity for biological dinitrogen fixation. Formation of root nodules is initiated by the binding and stabilization of rhizobia to plant root hairs, mediated in part by a receptor/ligand recognition system composed of lectins on the plant root surface and lectin-binding sites on the rhizobial cell surface. The dinitrogen fixation activity of these root nodules may be an important feature of enclosed, space-based life support systems, and may provide an ecological method to recycle nitrogen for amino acid production. However, the effects on nodule development of varied gravitational fields, or of root nutrient delivery hardware, remain unknown. We have investigated the effects of microgravity on root nodule formation, with preliminary experiments focused upon the receptor/ligand component. Microgravity, obtained during parabolic flight aboard NASA 930, has no apparent effect on the binding of purified lectin to rhizobia, a result that will facilitate forthcoming experiments using intact root tissues.

Potential of calcium isotopes to identify fractionations in vegetation: experimental approach

NASA Astrophysics Data System (ADS)

Cobert, F.; Schmitt, A.; Bourgade, P.; Stille, P.; Chabaux, F. J.; Badot, P.; Jaegler, T.

2010-12-01

This study aims to better understand the role of vegetation on the Ca cycle at the level of the critical zone of the Earth, in order to specify the mechanisms controlling the Ca absorption by plants at the rock/plant interface. To do this, we performed experiments using hydroponic plant cultures in a way that we could control the cooccuring geochemical and biological processes and determine the impact of the nutritive solution on the Ca cycle within plants. A dicotyledon and calcicole plant with rapid growth, the French bean (Phaseolus vulgaris L.), has been chosen to have access to one complete growth cycle. Several experiments have been conducted with two Ca concentrations, 5 (L) and 60 (H) ppm and two pH values (4 and 6) in the nutritive solution, for which the Ca concentration was maintained constant, so its Ca content is considered to be infinite. We determined Ca concentrations and isotopic ratios in the nutritive solution and in different organs (main roots, secondary roots, old and young stems, old and young leaves and fruits) at two different growth stages (10 days and 6 weeks). Our results show, in accord with previously published field studies, that the bean organs are all enriched in the light 40Ca isotope compared to the nutritive solution (e.g. Wigand et al., 2005; Page et al., 2008; Cenki-Tok et al., 2009; Holmden and Bélanger, 2010). We identify two fractionation levels. The first occurs during the uptake of the nutrient elements by the lateral roots. This implies that the main mechanisms of light isotope enrichments in the plant are due to electrochemical gradient transport processes taking place at this interface. The second fractionation can be observed within the plant itself and is due to the nature of the considered organ itself. Indeed structural reservoirs (primary roots, stem, reproductive organs) incorporate more the light 40Ca isotope compared to the transfer reservoirs (lateral roots, xylem sap, leaves). This could be linked to ion-exchange reactions with the pectins in the cell walls of the conducting xylem. However, we also observe that bean organs from L4 experiment growing in nutrient solutions with lower Ca concentrations and low pH behave slightly differently and show reduced Ca isotopic fractionations compared with beans from the other experiments. All these results indicate that there is no simple correlation between Ca isotopic variations, Ca content and pH of the nutrient solution, and that also biological effects have to be involved. The data confirm the potential of the Ca isotopic system for tracing biological fractionations in natural ecosystems. Wiegand et al., (2005). Geophys. Res. Lett., 32, L11404 Page et al., (2008). Biogeochemistry, 88, 1-13 Cenki-Tok et al,. (2009). Geochim. Cosmochim. Acta, 73, 2215-2228 Holmden and Bélanger(2010). Geochim. Cosmochim. Acta, 74, 995-1015

A new flavanenol with urease-inhibition activity isolated from roots of manna plant camelthorn ( Alhagi maurorum)

NASA Astrophysics Data System (ADS)

Laghari, Abdul Hafeez; Memon, Shahabuddin; Nelofar, Aisha; Khan, Khalid M.; Yasmin, Arfa; Syed, Muhammad Noman; Aman, Afsheen

2010-02-01

A new flavanenol ( 1) was isolated from ethyl acetate fraction of roots of Alhagi maurorum (Fabaceae). Its structure was elucidated on the basis of spectroscopic evidence using elemental analysis, IR, MS, and NMR techniques. It was determined to be 5,6,7,8,2',3',5',6'-octamethoxyflavan-3-en-4'-ol. Experiments were carried out to evaluate its urease-inhibition activity. From the observations it has been noticed that flavanenol possesses remarkable urease-inhibitory effect.

Anatomical analysis of the resected roots of mandibular first molars after failed non-surgical retreatment

PubMed Central

2018-01-01

Objectives Understanding the reason for an unsuccessful non-surgical endodontic treatment outcome, as well as the complex anatomy of the root canal system, is very important. This study examined the cross-sectional root canal structure of mandibular first molars confirmed to have failed non-surgical root canal treatment using digital images obtained during intentional replantation surgery, as well as the causative factors of the failed conventional endodontic treatments. Materials and Methods This study evaluated 115 mandibular first molars. Digital photographic images of the resected surface were taken at the apical 3 mm level and examined. The discolored dentin area around the root canal was investigated by measuring the total surface area, the treated areas as determined by the endodontic filling material, and the discolored dentin area. Results Forty 2-rooted teeth showed discolored root dentin in both the mesial and distal roots. Compared to the original filled area, significant expansion of root dentin discoloration was observed. Moreover, the mesial roots were significantly more discolored than the distal roots. Of the 115 molars, 92 had 2 roots. Among the mesial roots of the 2-rooted teeth, 95.7% of the roots had 2 canals and 79.4% had partial/complete isthmuses and/or accessory canals. Conclusions Dentin discoloration that was not visible on periapical radiographs and cone-beam computed tomography was frequently found in mandibular first molars that failed endodontic treatment. The complex anatomy of the mesial roots of the mandibular first molars is another reason for the failure of conventional endodontic treatment. PMID:29765897

Ammonium and Nitrate Uptake by the Floating Plant Landoltia punctata

PubMed Central

Fang, Yun Ying; Babourina, Olga; Rengel, Zed; Yang, Xiao E.; Pu, Pei Min

2007-01-01

Background and Aims Plants from the family Lemnaceae are widely used in ecological engineering projects to purify wastewater and eutrophic water bodies. However, the biology of nutrient uptake mechanisms in plants of this family is still poorly understood. There is controversy over whether Lemnaceae roots are involved in nutrient uptake. No information is available on nitrogen (N) preferences and capacity of Landoltia punctata (dotted duckweed), one of the best prospective species in Lemnaceae for phytomelioration and biomass production. The aim of this study was to assess L. punctata plants for their ability to take up NH4+ and NO3− by both roots and fronds. Methods NO3− and NH4+ fluxes were estimated by a non-invasive ion-selective microelectrode technique. This technique allows direct measurements of ion fluxes across the root or frond surface of an intact plant. Key Results Landoltia punctata plants took up NH4+ and NO3− by both fronds and roots. Spatial distribution of NH4+ and NO3− fluxes demonstrated that, although ion fluxes at the most distal parts of the root were uneven, the mature part of the root was involved in N uptake. Despite the absolute flux values for NH4+ and NO3− being lower in roots than at the frond surface, the overall capacity of roots to take up ions was similar to that of fronds because the surface area of roots was larger. L. punctata plants preferred to take up NH4+ over NO3− when both N sources were available. Conclusions Landoltia punctata plants take up nitrogen by both roots and fronds. When both sources of N are available, plants prefer to take up NH4+, but will take up NO3− when it is the only N source. PMID:17204539

An In-Situ Root-Imaging System in the Context of Surface Detection of CO2

NASA Astrophysics Data System (ADS)

Apple, M. E.; Prince, J. B.; Bradley, A. R.; Zhou, X.; Lakkaraju, V. R.; Male, E. J.; Pickles, W.; Thordsen, J. J.; Dobeck, L.; Cunningham, A.; Spangler, L.

2009-12-01

Carbon sequestration is a valuable method of spatially confining CO2 belowground. The Zero Emissions Research Technology, (ZERT), site is an experimental facility in a former agricultural field on the Montana State University campus in Bozeman, Montana, where CO2 was experimentally released at a rate of 200kg/day in 2009 into a 100 meter underground injection well running parallel to the ground surface. This injection well, or pipe, has deliberate leaks at intervals, and CO2 travels from these leaks upward to the surface of the ground. The ZERT site is a model system designed with the purpose of testing methods of surface detection of CO2. One important aspect of surface detection is the determination of the effects of CO2 on the above and belowground portions of plants growing above sequestration fields. At ZERT, these plants consist of a pre-existing mixture of herbaceous species present at the agricultural field. Species growing at the ZERT site include several grasses, Dactylis glomerata (Orchard Grass), Poa pratensis (Kentucky Bluegrass), and Bromus japonicus (Japanese Brome); the nitrogen-fixing legumes Medicago sativa, (Alfalfa), and Lotus corniculatus, (Birdsfoot trefoil); and an abundance of Taraxacum officinale, (Dandelion). Although the aboveground parts of the plants at high CO2 are stressed, as indicated by changes in hyperspectral plant signatures, leaf fluorescence and leaf chlorophyll content, we are interested in determining whether the roots are also stressed. To do so, we are combining measurements of soil conductivity and soil moisture with root imaging. We are using an in-situ root-imaging system manufactured by CID, Inc. (Camas, WA), along with image analysis software (Image-J) to analyze morphometric parameters in the images and to determine what effects, if any, the presence of leaking and subsequently upwelling CO2 has on the phenology of root growth, growth and turnover of individual fine and coarse roots, branching patterns, and root density and depth in the soil. We drilled three holes for the plexiglass root-imaging tubes in December 2008 and installed the tubes post-thaw in May 2009, with the initial set of images taken in July 2009 on the day preceding the 4-week long CO2 injection. We collected images weekly thereafter until late August 2009 by inserted a rotating camera into the tube and photographing at 10 cm intervals from the surface to a depth of 75-80 cm. By August 2009, roots were visible at 80 cm below ground. The root-imaging tubes will remain in place so that we can track the roots through the upcoming years at the ZERT site. Each year, we anticipate gathering images in the fall, winter, before the beginning of root growth in the spring, as well as during the summer injections of CO2. The information gained from these images will be useful in linking above and belowground responses of plants to CO2.

Effect of cold plasma treatment on seedling growth and nutrient absorption of tomato

NASA Astrophysics Data System (ADS)

Jiafeng, JIANG; Jiangang, LI; Yuanhua, DONG

2018-04-01

The effects of cold plasma (CP) treatment on seed germination, seedling growth, root morphology, and nutrient uptake of a tomato were investigated. The results showed that 80 W of CP treatment significantly increased tomato nitrogen (N) and phosphorus (P) absorption by 12.7% and 19.1%, respectively. CP treatment significantly improved the germination potential of tomato seed by 11.1% and the germination rate by 13.8%. Seedling growth characteristics, including total dry weight, root dry weight, root shoot rate, and leaf area, significantly increased after 80 W of CP treatment. Root activity was increased by 15.7% with 80 W of CP treatment, and 12.6% with 100 W of CP treatment. CP treatment (80 W) markedly ameliorated tomato root morphology, and root length, surface area, and volume, which increased 21.3%, 23.6%, and 29.0%, respectively. Our results suggested that CP treatment improved tomato N and P absorption by promoting the accumulation of shoot and root biomass, increasing the leaf area and root activity, and improving the length, surface area, and volume of root growth. Thus, CP treatment could be used in an ameliorative way to improve tomato nutrient absorption.

Toxicity of vanadium in soil on soybean at different growth stages.

PubMed

Yang, Jinyan; Wang, Mei; Jia, Yanbo; Gou, Min; Zeyer, Josef

2017-12-01

Vanadium(V) is present in trace amounts in most plants and widely distributed in soils. However, the environmental toxicity of V compound in soils is controversial. A greenhouse study with soybean from germination to bean production under exposure to pentavalent V [V(V)] was conducted to elucidate the interaction of plants and V fractions in soils and to evaluate the toxicity of V at different plant growth stages. Soybean growth has no effect on non-specific-bond and specific-bond fractions of V in soils, but V fractionation occurred in more extraction-resistant phases at high V concentrations. High concentrations of V(V) postponed the germination and growth of the soybeans. Bean production was less than half of that of the control at 500 mg kg -1 spiked V(V). For the 0 mg kg -1 spiked V(V) treated plants, the root was not the main location where V was retained. Vanadium in the soils at ≤ 250 mg kg -1 did not significantly affect the V concentration in the shoot and leaf of soybeans. With the increase in V concentration in soil, V concentrations in roots increased, whereas those in beans and pods decreased. From vegetative growth to the reproductive growth, the soybeans adsorbed more V and accumulated more V in the roots, with <20% transported to the aboveground parts. Hence, the analysis of V concentration in vegetative tissues or beans may not be a useful indicator for V pollution in soil. Meanwhile, the ratio of V concentration in cell wall to the total V concentration in the root increased with the increase in V(V) concentration in soils. Our results revealed that high concentrations of V inhibited soybean germination and biomass production. However, plants may produce self-defense systems to endure V toxicity. Copyright © 2017 Elsevier Ltd. All rights reserved.

Nitrogen cycle inferred by δ15N in larch stand in northern Mongolia

NASA Astrophysics Data System (ADS)

Hayashi, Mika; Lopez C., Maximo Larry; Nobori, Yoshihiro; Byambasuren, Mijidsuren; Boy, Jens

2017-04-01

Mongolia represents the southernmost border of boreal forests and therefore is more sensitive to climate change. In boreal regions forest grow under N-limited conditions and for this reason rely on ectomycorrhizal fungi for the uptake of inorganic and dissolved organic N from the soil solution. A drastic increase in air temperature and a decrease or almost no change in summer precipitation has led to a severe climate induced drought that is expected to impact the nitrogen cycle in this region. Until now there has been no study on the nitrogen dynamics and especially not by means of stable isotope in the entire Eurasian boreal forests. Thus, in this study we evaluate the effect of spatial and climatic characteristics on the soil-tree N exchange in three representative larch forest stands (Larix sibirica) in the forest-steppe zone of central Mongolia. The results showed significant differences in the soil available N content and the influence that this difference exerts on the level of N fractionation from roots to leaves. In this study we observed heavier d15N in fine roots than in short roots (where the ectomycorrhizal fungi is attached) which was used as a proxy for soil available d15N. This value did not match total N d15N in any of the three sites selected for this study even though total N d15N has been used in previous studies as a proxy for available N d15N. Higher fractionation was observed in forest stands where available N was more limited indicating a heavier reliance on ectomycorrhizal fungi for inorganic N uptake. Coincidentally, the site with less available N was the southern site with the lowest precipitation. The opposite was found in the northern sites where available N was higher and thus fractionation showed lower values. Different tree tissues (fine and short-roots, stem, leaves) and litter showed multiple, intra-plant processes that influenced the isotope signal of the source-sink nitrogen dynamics.

Simulated Nitrogen Deposition has Minor Effects on Ecosystem Pools and Fluxes of Energy, Elements, and Biochemicals in a Northern Hardwoods Forest

NASA Astrophysics Data System (ADS)

Talhelm, A. F.; Pregitzer, K. S.; Burton, A. J.; Xia, M.; Zak, D. R.

2017-12-01

The elemental and biochemical composition of plant tissues is an important influence on primary productivity, decomposition, and other aspects of biogeochemistry. Human activity has greatly altered biogeochemical cycles in ecosystems downwind of industrialized regions through atmospheric nitrogen deposition, but most research on these effects focuses on individual elements or steps in biogeochemical cycles. Here, we quantified pools and fluxes of biomass, the four major organic elements (carbon, oxygen, hydrogen, nitrogen), four biochemical fractions (lignin, structural carbohydrates, cell walls, and soluble material), and energy in a mature northern hardwoods forest in Michigan. We sampled the organic and mineral soil, fine and coarse roots, leaf litter, green leaves, and wood for chemical analyses. We then combined these data with previously published and archival information on pools and fluxes within this forest, which included replicated plots receiving either ambient deposition or simulated nitrogen deposition (3 g N m-2 yr-1 for 18 years). Live wood was the largest pool of energy and all elements and biochemical fractions. However, the production of wood, leaf litter, and fine roots represented similar fluxes of carbon, hydrogen, oxygen, cell wall material, and energy, while nitrogen fluxes were dominated by leaf litter and fine roots. Notably, the flux of lignin via fine roots was 70% higher than any other flux. Experimental nitrogen deposition had relatively few significant effects, increasing foliar nitrogen, increasing the concentration of lignin in the soil organic horizon and decreasing pools of all elements and biochemical fractions in the soil organic horizon except nitrogen, lignin, and structural carbohydrates. Overall, we found that differences in tissue chemistry concentrations were important determinants of ecosystem-level pools and fluxes, but that nitrogen deposition had little effect on concentrations, pools, or fluxes in this mature forest. Disclaimer: The views expressed in this poster are those of the authors and do not necessarily represent the views or policies of the U.S. EPA.

Ferulaldehyde and lupeol as direct and indirect antimicrobial compounds from Cordia gilletii (Boraginaceae) root barks.

PubMed

Okusa, Philippe N; Stévigny, Caroline; Névraumont, Marie; Gelbcke, Michel; Van Antwerpen, Pierre; Braekman, Jean Claude; Duez, Pierre

2014-05-01

Cordia gilletii De Wild (Boraginaceae), a medicinal plant used against infectious diseases in the Democratic Republic of Congo, was investigated for direct and indirect antimicrobial properties. On one hand, the methanol extract is active against many pathogenic bacteria, including resistant strains. Its bio-guided fractionation led to the isolation of ferulaldehyde; this compound showed antimicrobial and antioxidant properties that may support the activity we observed for the methanol extract and some of the traditional uses of C. gilletii. On the other hand, the n-hexane extract of root barks possesses indirect antimicrobial properties, enhancing the activity of antibiotics against methicillin-resistant Staphylococcus aureus (MRSA). The fractionation of this extract led to the isolation of lupeol, which decreases the minimum inhibitory concentration of several antibiotics (4 to 8 fold) against MRSA and contributes to the effects observed for the raw n-hexane extract.

Rooting depth varies differentially in trees and grasses as a function of mean annual rainfall in an African savanna.

PubMed

Holdo, Ricardo M; Nippert, Jesse B; Mack, Michelle C

2018-01-01

A significant fraction of the terrestrial biosphere comprises biomes containing tree-grass mixtures. Forecasting vegetation dynamics in these environments requires a thorough understanding of how trees and grasses use and compete for key belowground resources. There is disagreement about the extent to which tree-grass vertical root separation occurs in these ecosystems, how this overlap varies across large-scale environmental gradients, and what these rooting differences imply for water resource availability and tree-grass competition and coexistence. To assess the extent of tree-grass rooting overlap and how tree and grass rooting patterns vary across resource gradients, we examined landscape-level patterns of tree and grass functional rooting depth along a mean annual precipitation (MAP) gradient extending from ~ 450 to ~ 750 mm year -1 in Kruger National Park, South Africa. We used stable isotopes from soil and stem water to make inferences about relative differences in rooting depth between these two functional groups. We found clear differences in rooting depth between grasses and trees across the MAP gradient, with grasses generally exhibiting shallower rooting profiles than trees. We also found that trees tended to become more shallow-rooted as a function of MAP, to the point that trees and grasses largely overlapped in terms of rooting depth at the wettest sites. Our results reconcile previously conflicting evidence for rooting overlap in this system, and have important implications for understanding tree-grass dynamics under altered precipitation scenarios.

Direct and indirect effects of glomalin, mycorrhizal hyphae, and roots on aggregate stability in rhizosphere of trifoliate orange.

PubMed

Wu, Qiang-Sheng; Cao, Ming-Qin; Zou, Ying-Ning; He, Xin-hua

2014-07-25

To test direct and indirect effects of glomalin, mycorrhizal hyphae, and roots on aggregate stability, perspex pots separated by 37-μm nylon mesh in the middle were used to form root-free hyphae and root/hyphae chambers, where trifoliate orange (Poncirus trifoliata) seedlings were colonized by Funneliformis mosseae or Paraglomus occultum in the root/hyphae chamber. Both fungal species induced significantly higher plant growth, root total length, easily-extractable glomalin-related soil protein (EE-GRSP) and total GRSP (T-GRSP), and mean weight diameter (an aggregate stability indicator). The Pearson correlation showed that root colonization or soil hyphal length significantly positively correlated with EE-GRSP, difficultly-extractable GRSP (DE-GRSP), T-GRSP, and water-stable aggregates in 2.00-4.00, 0.50-1.00, and 0.25-0.50 mm size fractions. The path analysis indicated that in the root/hyphae chamber, aggregate stability derived from a direct effect of root colonization, EE-GRSP or DE-GRSP. Meanwhile, the direct effect was stronger by EE-GRSP or DE-GRSP than by mycorrhizal colonization. In the root-free hyphae chamber, mycorrhizal-mediated aggregate stability was due to total effect but not direct effect of soil hyphal length, EE-GRSP and T-GRSP. Our results suggest that GRSP among these tested factors may be the primary contributor to aggregate stability in the citrus rhizosphere.

Soybean Roots Grown under Heat Stress Show Global Changes in Their Transcriptional and Proteomic Profiles

DOE PAGES

Valdés-López, Oswaldo; Batek, Josef; Gomez-Hernandez, Nicolas; ...

2016-04-25

Heat stress is likely to be a key factor in the negative impact of climate change on crop production. Heat stress significantly influences the functions of roots, which provide support, water, and nutrients to other plant organs. Likewise, roots play an important role in the establishment of symbiotic associations with different microorganisms. Despite the physiological relevance of roots, few studies have examined their response to heat stress. Here in this study, we performed genome-wide transcriptomic and proteomic analyses on isolated root hairs, which are a single, epidermal cell type, and compared their response to stripped roots. On average, we identifiedmore » 1849 and 3091 genes differentially regulated in root hairs and stripped roots, respectively, in response to heat stress. Our gene regulatory module analysis identified 10 key modules that might control the majority of the transcriptional response to heat stress. We also conducted proteomic analysis on membrane fractions isolated from root hairs and compared these responses to stripped roots. These experiments identified a variety of proteins whose expression changed within 3 h of application of heat stress. Most of these proteins were predicted to play a significant role in thermo-tolerance, as well as in chromatin remodeling and post-transcriptional regulation. In conclusion, the data presented represent an in-depth analysis of the heat stress response of a single cell type in soybean.« less

Effects of 24-epibrassinolide on enzymatic browning and antioxidant activity of fresh-cut lotus root slices.

PubMed

Gao, Hui; Chai, HongKang; Cheng, Ni; Cao, Wei

2017-02-15

Fresh-cut lotus root slices were treated with 80nM 24-epibrassinolide (EBR) and then stored at 4°C for 8days to investigate the effects on cut surface browning. The results showed that EBR treatment reduced cut surface browning in lotus root slices and alleviated membrane lipid peroxidation as reflected by low malondialdehyde content and lipoxygenase activity. EBR treatment inhibited the activity of phenylalanine ammonia lyase and polyphenol oxidase, and subsequently decreased phenolics accumulation and soluble quniones formation. The treatment also stimulated the activity of peroxidase, catalase and ascorbate peroxidase and delayed the loss of ascorbic acid, which would help prevent membrane lipid peroxidation, as a consequence, reducing decompartmentation of enzymes and substrates causing enzymatic browning. These results indicate that EBR treatment is a promising attempt to control browning at cut surface of fresh-cut lotus root slices. Copyright © 2016 Elsevier Ltd. All rights reserved.

Rice Genotype Differences in Tolerance of Zinc-Deficient Soils: Evidence for the Importance of Root-Induced Changes in the Rhizosphere

PubMed Central

Mori, Asako; Kirk, Guy J. D.; Lee, Jae-Sung; Morete, Mark J.; Nanda, Amrit K.; Johnson-Beebout, Sarah E.; Wissuwa, Matthias

2016-01-01

Zinc (Zn) deficiency is a major constraint to rice production and Zn is also often deficient in humans with rice-based diets. Efforts to breed more Zn-efficient rice are constrained by poor understanding of the mechanisms of tolerance to deficiency. Here we assess the contributions of root growth and root Zn uptake efficiency, and we seek to explain the results in terms of specific mechanisms. We made a field experiment in a highly Zn-deficient rice soil in the Philippines with deficiency-tolerant and -sensitive genotypes, and measured growth, Zn uptake and root development. We also measured the effect of planting density. Tolerant genotypes produced more crown roots per plant and had greater uptake rates per unit root surface area; the latter was at least as important as root number to overall tolerance. Tolerant and sensitive genotypes took up more Zn per plant at greater planting densities. The greater uptake per unit root surface area, and the planting density effect can only be explained by root-induced changes in the rhizosphere, either solubilizing Zn, or neutralizing a toxin that impedes Zn uptake (possibly HCO3− or Fe2+), or both. Traits for these and crown root number are potential breeding targets. PMID:26793198

Rice Genotype Differences in Tolerance of Zinc-Deficient Soils: Evidence for the Importance of Root-Induced Changes in the Rhizosphere.

PubMed

Mori, Asako; Kirk, Guy J D; Lee, Jae-Sung; Morete, Mark J; Nanda, Amrit K; Johnson-Beebout, Sarah E; Wissuwa, Matthias

2015-01-01

Zinc (Zn) deficiency is a major constraint to rice production and Zn is also often deficient in humans with rice-based diets. Efforts to breed more Zn-efficient rice are constrained by poor understanding of the mechanisms of tolerance to deficiency. Here we assess the contributions of root growth and root Zn uptake efficiency, and we seek to explain the results in terms of specific mechanisms. We made a field experiment in a highly Zn-deficient rice soil in the Philippines with deficiency-tolerant and -sensitive genotypes, and measured growth, Zn uptake and root development. We also measured the effect of planting density. Tolerant genotypes produced more crown roots per plant and had greater uptake rates per unit root surface area; the latter was at least as important as root number to overall tolerance. Tolerant and sensitive genotypes took up more Zn per plant at greater planting densities. The greater uptake per unit root surface area, and the planting density effect can only be explained by root-induced changes in the rhizosphere, either solubilizing Zn, or neutralizing a toxin that impedes Zn uptake (possibly [Formula: see text] or Fe(2+)), or both. Traits for these and crown root number are potential breeding targets.

Plant roots use a patterning mechanism to position lateral root branches toward available water.

PubMed

Bao, Yun; Aggarwal, Pooja; Robbins, Neil E; Sturrock, Craig J; Thompson, Mark C; Tan, Han Qi; Tham, Cliff; Duan, Lina; Rodriguez, Pedro L; Vernoux, Teva; Mooney, Sacha J; Bennett, Malcolm J; Dinneny, José R

2014-06-24

The architecture of the branched root system of plants is a major determinant of vigor. Water availability is known to impact root physiology and growth; however, the spatial scale at which this stimulus influences root architecture is poorly understood. Here we reveal that differences in the availability of water across the circumferential axis of the root create spatial cues that determine the position of lateral root branches. We show that roots of several plant species can distinguish between a wet surface and air environments and that this also impacts the patterning of root hairs, anthocyanins, and aerenchyma in a phenomenon we describe as hydropatterning. This environmental response is distinct from a touch response and requires available water to induce lateral roots along a contacted surface. X-ray microscale computed tomography and 3D reconstruction of soil-grown root systems demonstrate that such responses also occur under physiologically relevant conditions. Using early-stage lateral root markers, we show that hydropatterning acts before the initiation stage and likely determines the circumferential position at which lateral root founder cells are specified. Hydropatterning is independent of endogenous abscisic acid signaling, distinguishing it from a classic water-stress response. Higher water availability induces the biosynthesis and transport of the lateral root-inductive signal auxin through local regulation of tryptophan aminotransferase of Arabidopsis 1 and PIN-formed 3, both of which are necessary for normal hydropatterning. Our work suggests that water availability is sensed and interpreted at the suborgan level and locally patterns a wide variety of developmental processes in the root.

Surface features of soil particles of three types of soils under different land use strategies

NASA Astrophysics Data System (ADS)

Matveeva, Nataliy; Kotelnikova, Anna; Rogova, Olga; Proskurnin, Mikhail

2017-04-01

Nowadays, there is a clear need in a deep investigation of molecular composition of soils and of its influence on surface characteristics of soil particles. The aim of this study is to evaluate the composition and properties of physical fractions in different soil types in determining functional specificity of soil solid-phase surface. The experiments were carried out with three different types of Russian soils—Sod-Podzolic, Chestnut, and Chernozem soils—under various treatments (fallow, different doses of mineral fertilizers and their aftereffects). The samples were separated into three fractions: silt (SF) with a particle size of <2 μm, light fraction (LF) with a density of <2 g/cm3, and residual fraction (RF) with a size >2 μm and the density >2 g/cm3. We measured specific surface area, surface hydrophobicity (contact angle, CA), ζ-potential, and the point of zero charge (PZC). For Chernozem and Chestnut soils and their fractions of we observed an increase in hydrophobicity for SF and RF under fertilizer treatment. At the sites not treated with fertilizers and aftereffect sites, the hydrophobicity of fractions was lower compared to the sites under treatment. The CA of the original soils and fractions were different: in 35% of cases CA was higher for SF and RF by 12-16%. The rest of samples demonstrated CA of all three physical fractions lower than CA of the original soil. The variability of the mean CA indicates considerable differences in ζ-potential and PZC between different types of soils and soil fractions. The results of potentiometric titration of PZC for Sod-Podzolic soil showed that all values are in acidic range, which suggests predominance of acidic functional groups at the surface of soil particles. Specific surface area determines soil sorption processes, bioavailability of nutrients, water etc. Here, specific surface area of Sod-Podzolic soil was low and SF-dependent. We calculated specific surface charge from obtained data on specific surface area and PZC. The results suggested considerable differences between sorption features of both soils and fractions under different land use strategies.

Reducing Strength Prevailing at Root Surface of Plants Promotes Reduction of Ag+ and Generation of Ag0/Ag2O Nanoparticles Exogenously in Aqueous Phase

PubMed Central

Pardha-Saradhi, Peddisetty; Yamal, Gupta; Peddisetty, Tanuj; Sharmila, Peddisetty; Nagar, Shilpi; Singh, Jyoti; Nagarajan, Rajamani; Rao, Kottapalli S.

2014-01-01

Potential of root system of plants from wide range of families to effectively reduce membrane impermeable ferricyanide to ferrocyanide and blue coloured 2,6-dichlorophenol indophenol (DCPIP) to colourless DCPIPH2 both under non-sterile and sterile conditions, revealed prevalence of immense reducing strength at root surface. As generation of silver nanoparticles (NPs) from Ag+ involves reduction, present investigations were carried to evaluate if reducing strength prevailing at surface of root system can be exploited for reduction of Ag+ and exogenous generation of silver-NPs. Root system of intact plants of 16 species from 11 diverse families of angiosperms turned clear colorless AgNO3 solutions, turbid brown. Absorption spectra of these turbid brown solutions showed silver-NPs specific surface plasmon resonance peak. Transmission electron microscope coupled with energy dispersive X-ray confirmed the presence of distinct NPs in the range of 5–50 nm containing Ag. Selected area electron diffraction and powder X-ray diffraction patterns of the silver NPs showed Bragg reflections, characteristic of crystalline face-centered cubic structure of Ag0 and cubic structure of Ag2O. Root system of intact plants raised under sterile conditions also generated Ag0/Ag2O-NPs under strict sterile conditions in a manner similar to that recorded under non-sterile conditions. This revealed the inbuilt potential of root system to generate Ag0/Ag2O-NPs independent of any microorganism. Roots of intact plants reduced triphenyltetrazolium to triphenylformazon and impermeable ferricyanide to ferrocyanide, suggesting involvement of plasma membrane bound dehydrogenases in reduction of Ag+ and formation of Ag0/Ag2O-NPs. Root enzyme extract reduced triphenyltetrazolium to triphenylformazon and Ag+ to Ag0 in presence of NADH, clearly establishing potential of dehydrogenases to reduce Ag+ to Ag0, which generate Ag0/Ag2O-NPs. Findings presented in this manuscript put forth a novel, simple, economically viable and green protocol for synthesis of silver-NPs under ambient conditions in aqueous phase, using root system of intact plants. PMID:25184239

[Biologically active compounds from the aqueous extract of Urtica dioica].

PubMed

Wagner, H; Willer, F; Kreher, B

1989-10-01

From the water extract of the roots of Urtica dioica (stinging nettle) a polysaccharide fraction was isolated which revealed activity in the carrageenan rat paw edema model and lymphocyte transformation test. Ion exchange chromatography and gel filtration of this fraction afforded 4 different polysaccharides, one of which reduced dose dependent hemolysis in the classical pathway of the complement test. The Urtica dioica lectin (UDA) was reisolated and found to stimulate the proliferation of human lymphocytes.

Effect of botanical immunomodulators on human CYP3A4 inhibition: implications for concurrent use as adjuvants in cancer therapy.

PubMed

Patil, Dada; Gautam, Manish; Gairola, Sunil; Jadhav, Suresh; Patwardhan, Bhushan

2014-03-01

Many botanical immunomodulators are used as adjuvants along with cancer chemotherapy. However, information on the impact of concurrent administration of such botanicals on pharmacokinetics of chemotherapy agents is inadequate. This study investigates inhibitory activities of 3 popular botanical adjuvants: ASPARAGUS RACEMOSU: (root aqueous extract; ARE), WITHANIA SOMNIFER: (root aqueous extract; WSE), and TINOSPORA CORDIFOLI: (stem aqueous extract, TCE) on human CYP3A4 isoenzyme, responsible for metabolism of several chemotherapy agents. . Testosterone 6-β hydroxylation was monitored using high-performance liquid chromatography as an indicator of CYP3A4 catalytic activities. Ketoconazole (positive control) and extracts were studied at their in vivo-relevant concentrations. TCE showed mild inhibition while no significant inhibitory activities were observed in WSE and ARE. TCE was further fractionated to obtain polar and nonpolar fractions. The nonpolar fraction showed significant CYP3A4 inhibition with IC50 13.06 ± 1.38 µg/mL. Major constituents of nonpolar fraction were identified using HPLC-DAD-MS profiling as berberine, jatrorrhizine, and palmatine, which showed IC50 values as 6.25 ± 0.30, 15.18 ± 1.59, and 15.53 ± 1.89 µg/mL, respectively. Our findings suggest that constituents of TCE extract especially protoberberine alkaloids have the potential to interact with cancer chemotherapy agents that are metabolized by CYP3A4 in vivo.

Evidence that Soil Properties and Organic Coating Drive the Phytoavailability of Cerium Oxide Nanoparticles.

PubMed

Layet, Clément; Auffan, Mélanie; Santaella, Catherine; Chevassus-Rosset, Claire; Montes, Mélanie; Ortet, Philippe; Barakat, Mohamed; Collin, Blanche; Legros, Samuel; Bravin, Matthieu N; Angeletti, Bernard; Kieffer, Isabelle; Proux, Olivier; Hazemann, Jean-Louis; Doelsch, Emmanuel

2017-09-05

The ISO-standardized RHIZOtest is used here for the first time to decipher how plant species, soil properties, and physical-chemical properties of the nanoparticles and their transformation regulate the phytoavailability of nanoparticles. Two plants, tomato and fescue, were exposed to two soils with contrasted properties: a sandy soil poor in organic matter and a clay soil rich in organic matter, both contaminated with 1, 15, and 50 mg·kg -1 of dissolved Ce 2 (SO 4 ) 3 , bare and citrate-coated CeO 2 nanoparticles. All the results demonstrate that two antagonistic soil properties controlled Ce uptake. The clay fraction enhanced the retention of the CeO 2 nanoparticles and hence reduced Ce uptake, whereas the organic matter content enhanced Ce uptake. Moreover, in the soil poor in organic matter, the organic citrate coating significantly enhanced the phytoavailability of the cerium by forming smaller aggregates thereby facilitating the transport of nanoparticles to the roots. By getting rid of the dissimilarities between the root systems of the different plants and the normalizing the surfaces exposed to nanoparticles, the RHIZOtest demonstrated that the species of plant did not drive the phytoavailability, and provided evidence for soil-plant transfers at concentrations lower than those usually cited in the literature and closer to predicted environmental concentrations.

Developmental distribution of the plasma membrane-enriched proteome in the maize primary root growth zone.

PubMed

Zhang, Zhe; Voothuluru, Priyamvada; Yamaguchi, Mineo; Sharp, Robert E; Peck, Scott C

2013-01-01

Within the growth zone of the maize primary root, there are well-defined patterns of spatial and temporal organization of cell division and elongation. However, the processes underlying this organization remain poorly understood. To gain additional insights into the differences amongst the defined regions, we performed a proteomic analysis focusing on fractions enriched for plasma membrane (PM) proteins. The PM is the interface between the plant cell and the apoplast and/or extracellular space. As such, it is a key structure involved in the exchange of nutrients and other molecules as well as in the integration of signals that regulate growth and development. Despite the important functions of PM-localized proteins in mediating these processes, a full understanding of dynamic changes in PM proteomes is often impeded by low relative concentrations relative to total proteins. Using a relatively simple strategy of treating microsomal fractions with Brij-58 detergent to enrich for PM proteins, we compared the developmental distribution of proteins within the root growth zone which revealed a number of previously known as well as novel proteins with interesting patterns of abundance. For instance, the quantitative proteomic analysis detected a gradient of PM aquaporin proteins similar to that previously reported using immunoblot analyses, confirming the veracity of this strategy. Cellulose synthases increased in abundance with increasing distance from the root apex, consistent with expected locations of cell wall deposition. The similar distribution pattern for Brittle-stalk-2-like protein implicates that this protein may also have cell wall related functions. These results show that the simplified PM enrichment method previously demonstrated in Arabidopsis can be successfully applied to completely unrelated plant tissues and provide insights into differences in the PM proteome throughout growth and development zones of the maize primary root.

Hounsfield unit change in root and alveolar bone during canine retraction.

PubMed

Jiang, Feifei; Liu, Sean S-Y; Xia, Zeyang; Li, Shuning; Chen, Jie; Kula, Katherine S; Eckert, George

2015-04-01

The objective of this study was to determine the Hounsfield unit (HU) changes in the alveolar bone and root surfaces during controlled canine retractions. Eighteen maxillary canine retraction patients were selected for this split-mouth design clinical trial. The canines in each patient were randomly assigned to receive either translation or controlled tipping treatment. Pretreatment and posttreatment cone-beam computed tomography scans of each patient were used to determine tooth movement direction and HU changes. The alveolar bone and root surface were divided into 108 divisions, respectively. The HUs in each division were measured. Mixed-model analysis of variance was applied to test the HU change distribution at the P <0.05 significance level. The HU changes varied with the directions relative to the canine movement. The HU reductions occurred at the root surfaces. Larger reductions occurred in the divisions that were perpendicular to the moving direction. However, HUs decreased in the alveolar bone in the moving direction. The highest HU reduction was at the coronal level. HU reduction occurs on the root surface in the direction perpendicular to tooth movement and in the alveolar bone in the direction of tooth movement when a canine is retracted. Copyright © 2015 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.

Hounsfield Unit Change in Root and Alveolar Bone during Canine Retraction

PubMed Central

Jiang, Feifei; Liu, Sean Y.; Xia, Zeyang; Li, Shuning; Chen, Jie; Kula, Katherine S.; Eckert, George

2014-01-01

Objectives The objective of this study was to determine the Hounsfield unit (HU) changes in the alveolar bone and root surface during controlled canine retractions. Methods Eighteen maxillary canine retraction patients were selected for this split mouth design clinical trial. The canines in each patient were randomly assigned to receive either translation or controlled tipping treatment strategy. Pre- and post-treatment cone beam computed tomography scans of each patient were used to determine tooth movement direction and HU changes. The alveolar bone and root surface were divided into 108 divisions, respectively. The HU in each division was measured. The Mixed-model ANOVA was applied to test the HU change distribution at the p<0.05 significant level. Results The HU changes varied with the directions relative to the canine movement. The HU reduction occurred at the root surface. Larger reductions occurred in the divisions that were perpendicular to the moving direction. However, HU decreased in the alveolar bone in the moving direction. The highest HU reduction was at the coronal level. Conclusions HU reduction occurs on the root surface in the direction perpendicular to the tooth movement and in the alveolar bone in the direction of tooth movement when a canine is retracted. PMID:25836004

[Cell surface peroxidase--generator of superoxide anion in wheat root cells under wound stress].

PubMed

Chasov, A V; Gordon, L Kh; Kolesnikov, O P; Minibaeva, F V

2002-01-01

Development of wound stress in excised wheat roots is known to be accompanied with an increase in reactive oxygen species (ROS) production, fall of membrane potential, release of K+ from cells, alkalization of extracellular solution, changes in respiration and metabolism of structural lipids. Dynamics of superoxide release correlates with changes in other physiological parameters, indicating the cross-reaction of these processes. Activity of peroxidase in extracellular solution after a 1 h incubation and removal of roots was shown to be stimulated by the range of organic acids, detergents, metals, and to be inhibited by cyanide. Superoxide production was sensitive to the addition of Mn2+ and H2O2. Increase in superoxide production correlates with the enhancement of peroxidase activity at the application of organic acids and detergents. The results obtained indicate that cell surface peroxidase is one of the main generators of superoxide in wounded wheat root cells. Different ways of stimulation of the ROS producing activity in root cells is supposed. By controlling superoxide and hydrogen peroxide formation, the cell surface peroxidase can control the adaptation processes in stressed plant cells.

Effect of endodontic irrigating solutions on the microhardness and roughness of root canal dentin: an in vitro study.

PubMed

Patil, Chetan R; Uppin, Veerendra

2011-01-01

To evaluate the effect of widely used endodontic irrigating solutions on root dentin microhardness and surface roughness. One hundred twenty, non-carious extracted human permanent incisor teeth were selected. The crowns of the teeth were sectioned and the roots were separated longitudinally to get 240 specimens. These specimens were then divided into six groups according to the irrigating solutions used. The solutions used were 5% and 2.5% NaOCl solutions, 3% H2 O2 , 17% EDTA solution, 0.2% chlorhexidine gluconate, and distilled water. Then, the specimens were subjected to microhardness and roughness testing. The data were analyzed using ANOVA and Tukey's multiple comparison tests. The results of this study indicated that all irrigation solutions, except 0.2% chlorhexidine gluconate, decreased the microhardness of root dentin, and 3% H2 O2 and 0.2% chlorhexidine gluconate had no effect on surface roughness. Within the limitation of this study, it is concluded that 0.2% chlorhexidine gluconate seems to be an appropriate irrigation solution, because of its harmless effect on the microhardness and surface roughness of root canal dentin.

Complexation of lead by Bermuda grass root exudates in aqueous media.

PubMed

Thomas, Catherine; Butler, Afrachanna; Larson, Steven; Medina, Victor; Begonia, Maria

2014-01-01

Exudates produced from Bermuda grass roots were collected in deionized water from sterilized Bermuda grass sod at 3-day intervals over a period of 15 days. Exudates were analyzed for total organic carbon, and characterized via Fourier Transform Infrared Spectroscopy. Exudate samples were adjusted to pH values of 4.5, 6.5, and 7.5, amended with lead and quantified for soluble and complexed lead via Inductively Coupled Plasma--Optical Emission Spectrometry. Data obtained from total organic carbon measurements indicated compositional changes in Bermuda grass root exudates as organic carbon concentrations increased over time. Analysis of the infrared spectroscopy data indicated that carboxylic acids and amine functional groups were present in root exudates. Also, the ability of root-exuded compounds to solubilize lead in aqueous media was demonstrated as exudate samples dissolved an average of 60% more lead than deionized water. At pH values 4.5 and 7.5, lead complexation by Bermuda grass root exudates increased with decreasing molecular weight size fractions, while an opposite trend was observed at pH 6.5. Results from this study demonstrated the ability of Bermuda grass root exudates to complex lead in aqueous media.

Increased synthesis of a new oleanane-type saponin in hairy roots of marigold (Calendula officinalis) after treatment with jasmonic acid.

PubMed

Markowski, Michał; Długosz, Marek; Szakiel, Anna; Durli, Mathieu; Poinsignon, Sophie; Bouguet-Bonnet, Sabine; Vernex-Loset, Lionel; Krier, Gabriel; Henry, Max

2018-04-18

Native plant of marigold (Calendula officinalis L.) synthesizes oleanolic acid saponins classified as glucosides or glucuronides according to the first residue in sugar chain bound to C-3 hydroxyl group. Hairy root culture, obtained by transformation with Agrobacterium rhizogenes strain 15834, exhibit a potent ability of synthesis of oleanolic acid glycosides. The HPLC profile of saponin fraction obtained from C. officinalis hairy roots treated with plant stress hormone, jasmonic acid, showed the 10-times increase of the content of one particular compound, determined by NMR and MALDI TOF as a new bisdesmoside saponin, 3-O-β-d-glucuronopyranosyl-28-O-β-d-galactopyranosyl-oleanolic acid. Such a diglycoside does not occur in native C. officinalis plant. It is a glucuronide, whereas in the native plant glucuronides are mainly accumulated in flowers, while glucosides are the most abundant saponins in roots. Thus, our results revealed that the pathways of saponin biosynthesis, particularly reactions of glycosylation, are altered in C. officinalis hairy root culture.

Inhibitory effects of Turkish folk remedies on inflammatory cytokines: interleukin-1alpha, interleukin-1beta and tumor necrosis factor alpha.

PubMed

Yeşilada, E; Ustün, O; Sezik, E; Takaishi, Y; Ono, Y; Honda, G

1997-09-01

In this study, in vitro inhibitory effects of 55 extracts or fractions obtained from 10 plant species on interleukin-1 (IL-1alpha, IL-1beta) and tumor necrosis factor (TNF-alpha) biosynthesis were studied. The following plant materials from Turkish folk medicine for the treatment of various diseases which are thought to be inflammatory in nature e.g. rheumatism, fever, infections, edemas or related inflammatory diseases were selected as the subject of this study: Cistus laurifolius leaves, Clematis flammna flowering herbs, Crataegus orientalis roots, Daphne oleoides ssp. oleoides whole plant, Ecbalium elaterium roots, Rosa canina roots, Rubus discolor roots, Rubus hirtus roots, Sambucus ebulus flowers and leaves, Sambucus nigra flowers and leaves. All plants showed inhibitory activity against at least one of these models in various percentages depending upon the concentration, thus supporting the folkloric utilization. Daphne oleoides was found to be the most active plant against the test models.

In vitro antifungal activity of extracts obtained from Hypericum perforatum adventitious roots cultured in a mist bioreactor against planktonic cells and biofilm of Malassezia furfur.

PubMed

Simonetti, Giovanna; Tocci, Noemi; Valletta, Alessio; Brasili, Elisa; D'Auria, Felicia Diodata; Idoux, Alicia; Pasqua, Gabriella

2016-01-01

Xanthone-rich extracts from Hypericum perforatum root cultures grown in a Mist Bioreactor as antifungal agents against Malassezia furfur. Extracts of Hypericum perforatum roots grown in a bioreactor showed activity against planktonic cells and biofilm of Malassezia furfur. Dried biomass, obtained from roots grown under controlled conditions in a ROOTec mist bioreactor, has been extracted with solvents of increasing polarity (i.e. chloroform, ethyl acetate and methanol). The methanolic fraction was the richest in xanthones (2.86 ± 0.43 mg g(-1) DW) as revealed by HPLC. The minimal inhibitory concentration of the methanol extract against M. furfur planktonic cells was 16 μg mL(-1). The inhibition percentage of biofilm formation, at a concentration of 16 μg mL(-1), ranged from 14% to 39%. The results show that H. perforatum root extracts could be used as new antifungal agents in the treatment of Malassezia infections.

Partitioning Ecosystem Respiration Using Stable Carbon Isotopes in a Mixed C3 Annual Grassland

NASA Astrophysics Data System (ADS)

Tu, K. P.

2001-12-01

The stable carbon isotope ratio (δ 13C) of respired CO2 has been used to partition soil respiration into root and microbial components by exploiting the different δ 13C signals from C3 plants growing in a previously C4 dominated system (Rouchette, Angers and Flanagan 1999). We extend this approach and present data that attempts to partition ecosystem respiration using δ 13C analyses of all of the ecosystem compartments in a mixed C3 annual grassland that has not experienced recent C4 inputs. From December 2000 to February 2001 we measured δ 13C-CO2 respired from leaves, roots and sieved soil collected from a winter-active grassland near Ione, California. Two-source mixing models were used to calculate the contribution of each source to total system respiration by comparing their isotope signals to those from whole ecosystem respiration and soil surface efflux. Isotope ratios were measured on 10mL air samples in septum-capped vials using a Finnigan MAT Delta PlusXL IRMS/Gas Bench II interfaced to an autosampler (after Tu et al. 2001). The vials were filled with sample air in the field using a double-holed needle connected in a closed loop to a LI-6200 IRGA and a bottle containing the isolated samples (leaf, root, sieved soil, etc.). Leaves were clipped at ground level and roots and soil were separated by sieving soil cores. Sample δ 13CO2 signatures were determined by plotting the change in δ 13C against the inverse of CO2 concentration. On average, CO2 respired from sieved soil (-27.4o/oo+/-1.4) was slightly more depleted than that from leaves (-27.2o/oo+/-0.5), but much more depleted than the whole ecosystem (-24.9o/oo+/-0.6), the soil surface efflux (-23.8o/oo+/-0.9), and plant roots (-20.5o/oo+/-0.8). Based on these isotope values, leaf respiration comprised 33% of ecosystem respiration with 36% from roots and 31% from soil microbial respiration. Thus, over two-thirds of ecosystem respiration was autotrophic (plant-based) in origin with roughly one-third being heterotrophic. Belowground respiration, comprised of both autotrophic (root) and heterotrophic (microbial) components, accounted for nearly two-thirds of total ecosystem respiration. Root and microbial respiration each contributed to nearly half of total belowground respiration (53% and 47%, respectively). Similarly, plant respiration was divided nearly equally between that from roots (52%) and leaves (48%). Partitioning using natural abundance stable carbon isotope ratios was made possible because of the relatively large differences in δ 13C values among the various sources in this entirely C3 system. To our knowledge, such large isotopic differences in respired CO2 among different plant tissues and belowground components have not been documented before. Further research is needed to determine how such differences may arise and to establish if similar differences exist in other ecosystems or at different times of the growing season. Our results also imply that interpretation of above-canopy Keeling plot intercepts may be complicated by both multiple (and isotopically distinct) sources and by isotopic fractionation that occurs either during the respiration process itself or during the transfer of carbon compounds prior to respiration.

Sulphate reduction and nitrogen fixation rates associated with roots, rhizomes and sediments from Zostera noltii and Spartina maritima meadows.

PubMed

Nielsen, L B; Finster, K; Welsh, D T; Donelly, A; Herbert, R A; de Wit, R; Lomstein, B A

2001-01-01

Sulphate reduction rates (SRR) and nitrogen fixation rates (NFR) associated with isolated roots, rhizomes and sediment from the rhizosphere of the marine macrophytes Zostera noltii and Spartina maritima, and the presence and distribution of Bacteria on the roots and rhizomes, were investigated. Between 1% and 3% of the surface area of the roots and rhizomes of both macrophytes were colonized by Bacteria. Bacteria on the surfaces of S. maritima roots and rhizomes were evenly distributed, while the distribution of Bacteria on Z. noltii roots and rhizomes was patchy. Root- and rhizome-associated SRR and NFR were always higher than rates in the bulk sediment. In particular, nitrogen fixation associated with the roots and rhizomes was 41-650-fold higher than in the bulk sediment. Despite the fact that sulphate reduction was elevated on roots and rhizomes compared with bulk sediment, the contribution of plant-associated sulphate reduction to overall sulphate reduction was small (< or =11%). In contrast, nitrogen fixation associated with the roots and rhizomes accounted for 31% and 91% of the nitrogen fixed in the rhizosphere of Z. noltii and S. maritima respectively. In addition, plant-associated nitrogen fixation could supply 37-1,613% of the nitrogen needed by the sulphate-reducing community. Sucrose stimulated nitrogen fixation and sulphate reduction significantly in the root and rhizome compartments of both macrophytes, but not in the bulk sediment.

Wound-induced expression of horseradish peroxidase.

PubMed

Kawaoka, A; Kawamoto, T; Ohta, H; Sekine, M; Takano, M; Shinmyo, A

1994-01-01

Peroxidases have been implicated in the responses of plants to physiological stress and to pathogens. Wound-induced peroxidase of horseradish (Armoracia rusticana) was studied. Total peroxidase activity was increased by wounding in cell wall fractions extracted from roots, stems and leaves of horseradish. On the other hand, wounding decreased the peroxidase activity in the soluble fraction from roots. The enzyme activities of the basic isozymes were induced by wounding in horseradish leaves based on data obtained by fractionation of crude enzyme in isoelectric focusing gel electrophoresis followed by activity staining. We have previously isolated genomic clones for four peroxidase genes, namely, prxC1a, prxC1b, prxC2 and prxC3. Northern blot analysis using gene-specific probes showed that mRNA of prxC2, which encodes a basic isozyme, accumulated by wounding, while the mRNAs for other peroxidase genes were not induced. Tobacco (Nicotiana tabacum) plants were transformed with four chimeric gene constructs, each consisting of a promoter from one of the peroxidase genes and the β-glucuronidase (GUS) structural gene. High level GUS activity induced in response to wounding was observed in tobacco plants containing the prxC2-GUS construct.

Kinetics of Diffusional Droplet Growth in a Liquid/Liquid Two-Phase System

NASA Technical Reports Server (NTRS)

Glicksman, M. E.; Fradkov, V. E.

1996-01-01

We address the problem of diffusional interactions in a finite sized cluster of spherical particles for volume fractions, V(sub v) in the range 0-0.01. We determined the quasi-static monopole diffusion solution for n particles distributed at random in a continuous matrix. A global mass conservation condition is employed, obviating the need for any external boundary condition. The numerical results provide the instantaneous (snapshot) growth or shrinkage rate of each particle, precluding the need for extensive time-dependent computations. The close connection between these snapshot results and the coarsegrained kinetic constants are discussed. A square-root dependence of the deviations of the rate constants from their zero volume fraction value is found for the higher V(sub v) investigated. This behavior is consistent with predictions from diffusion Debye-Huckel screening theory. By contrast, a cube-root dependence, reported in earlier numerical studies, is found for the lower V(sub v) investigated. The roll-over region of the volume fraction where the two asymptotics merge depends on the number of particles, n, alone. A theoretical estimate for the roll-over point predicts that the corresponding V(sub v) varies as n(sup -2), in good agreement with the numerical results.

Evaluation of the Effects of Er,Cr:YSGG Laser, Ultrasonic Scaler and Curette on Root Surface Profile Using Surface Analyser and Scanning Electron Microscope: An In Vitro Study.

PubMed

Arora, Shipra; Lamba, Arundeep Kaur; Faraz, Farrukh; Tandon, Shruti; Ahad, Abdul

2016-01-01

Introduction: The periodontal therapy is primarily targeted at removal of dental plaque and plaque retentive factors. Although the thorough removal of adherent plaque, calculus and infected root cementum is desirable, it is not always achieved by conventional modalities. To accomplish more efficient results several alternative devices have been used. Lasers are one of the most promising modalities for nonsurgical periodontal treatment as they can achieve excellent tissue ablation with strong bactericidal and detoxification effects. Methods: Thirty freshly extracted premolars were selected and decoronated. The mesial surface of each root was divided vertically into four approximately equal parts. These were distributed into four group based on the root surface treatment. Part A (n = 30) was taken as control and no instrumentation was performed. Part B (n = 30) was irradiated by Erbium, Chromium doped Yttrium Scandium Gallium Garnet (Er,Cr:YSGG) laser. Part C (n = 30) was treated by piezoelectric ultrasonic scaler. Part D (n = 30) was treated by Gracey curette. The surface roughness was quantitatively analyzed by profilometer using roughness average (Ra) value, while presence of smear layer, cracks, craters and melting of surface were analyzed using scanning electron microscope (SEM). The means across the groups were statistically compared with control using Dunnett test. Results: Among the test groups, Er,Cr:YSGG laser group showed maximum surface roughness (mean Ra value of 4.14 μm) as compared to ultrasonic scaler (1.727 μm) and curette group (1.22 μm). However, surface with smear layer were found to be maximum (50%) in curette treated samples and minimum (20%) in laser treated ones. Maximum cracks (83.34%) were produced by ultrasonic scaler, and minimum (43.33%) by curettes. Crater formation was maximum (50%) in laser treated samples and minimum (3.33%) in curette treated ones. 63.33% samples treated by laser demonstrated melting of root surface, followed by ultrasonic scaler and curettes. Conclusion: Er,Cr:YSGG laser produced maximum microstructural changes on root surface that can influence the attachment of soft periodontal tissues as well as plaque and calculus deposition. In vivo studies are needed to validate these results and to evaluate their clinical effects.

Bacteria Associated to Plants Naturally Selected in a Historical PCB Polluted Soil Show Potential to Sustain Natural Attenuation.

PubMed

Vergani, Lorenzo; Mapelli, Francesca; Marasco, Ramona; Crotti, Elena; Fusi, Marco; Di Guardo, Antonio; Armiraglio, Stefano; Daffonchio, Daniele; Borin, Sara

2017-01-01

The exploitation of the association between plants and microorganisms is a promising approach able to boost natural attenuation processes for soil clean-up in vast polluted areas characterized by mixed chemical contamination. We aimed to explore the selection of root-associated bacterial communities driven by different plant species spontaneously established in abandoned agricultural soils within a historical polluted site in north Italy. The site is highly contaminated by chlorinated persistent organic pollutants, mainly constituted by polychlorobiphenyls (PCBs), together with heavy metals and metalloids, in variable concentrations and uneven distribution. The overall structure of the non-vegetated and root-associated soil fractions bacterial communities was described by high-throughput sequencing of the 16S rRNA gene, and a collection of 165 rhizobacterial isolates able to use biphenyl as unique carbon source was assayed for plant growth promotion (PGP) traits and bioremediation potential. The results showed that the recruitment of specific bacterial communities in the root-associated soil fractions was driven by both soil fractions and plant species, explaining 21 and 18% of the total bacterial microbiome variation, respectively. PCR-based detection in the soil metagenome of bacterial bphA gene, encoding for the biphenyl dioxygenase α subunit, indicated that the soil in the site possesses metabolic traits linked to PCB degradation. Biphenyl-utilizing bacteria isolated from the rhizosphere of the three different plant species showed low phylogenetic diversity and well represented functional traits, in terms of PGP and bioremediation potential. On average, 72% of the strains harbored the bphA gene and/or displayed catechol 2,3-dioxygenase activity, involved in aromatic ring cleavage. PGP traits, including 1-aminocyclopropane-1-carboxylic acid deaminase activity potentially associated to plant stress tolerance induction, were widely distributed among the isolates according to in vitro assays. PGP tested in vivo on tomato plants using eleven selected bacterial isolates, confirmed the promotion and protection potential of the rhizosphere bacteria. Different spontaneous plant species naturally selected in a historical chronically polluted site showed to determine the enrichment of peculiar bacterial communities in the soil fractions associated to the roots. All the rhizosphere communities, nevertheless, hosted bacteria with degradation/detoxification and PGP potential, putatively sustaining the natural attenuation process.

Bacteria Associated to Plants Naturally Selected in a Historical PCB Polluted Soil Show Potential to Sustain Natural Attenuation

PubMed Central

Vergani, Lorenzo; Mapelli, Francesca; Marasco, Ramona; Crotti, Elena; Fusi, Marco; Di Guardo, Antonio; Armiraglio, Stefano; Daffonchio, Daniele; Borin, Sara

2017-01-01

The exploitation of the association between plants and microorganisms is a promising approach able to boost natural attenuation processes for soil clean-up in vast polluted areas characterized by mixed chemical contamination. We aimed to explore the selection of root-associated bacterial communities driven by different plant species spontaneously established in abandoned agricultural soils within a historical polluted site in north Italy. The site is highly contaminated by chlorinated persistent organic pollutants, mainly constituted by polychlorobiphenyls (PCBs), together with heavy metals and metalloids, in variable concentrations and uneven distribution. The overall structure of the non-vegetated and root-associated soil fractions bacterial communities was described by high-throughput sequencing of the 16S rRNA gene, and a collection of 165 rhizobacterial isolates able to use biphenyl as unique carbon source was assayed for plant growth promotion (PGP) traits and bioremediation potential. The results showed that the recruitment of specific bacterial communities in the root-associated soil fractions was driven by both soil fractions and plant species, explaining 21 and 18% of the total bacterial microbiome variation, respectively. PCR-based detection in the soil metagenome of bacterial bphA gene, encoding for the biphenyl dioxygenase α subunit, indicated that the soil in the site possesses metabolic traits linked to PCB degradation. Biphenyl-utilizing bacteria isolated from the rhizosphere of the three different plant species showed low phylogenetic diversity and well represented functional traits, in terms of PGP and bioremediation potential. On average, 72% of the strains harbored the bphA gene and/or displayed catechol 2,3-dioxygenase activity, involved in aromatic ring cleavage. PGP traits, including 1-aminocyclopropane-1-carboxylic acid deaminase activity potentially associated to plant stress tolerance induction, were widely distributed among the isolates according to in vitro assays. PGP tested in vivo on tomato plants using eleven selected bacterial isolates, confirmed the promotion and protection potential of the rhizosphere bacteria. Different spontaneous plant species naturally selected in a historical chronically polluted site showed to determine the enrichment of peculiar bacterial communities in the soil fractions associated to the roots. All the rhizosphere communities, nevertheless, hosted bacteria with degradation/detoxification and PGP potential, putatively sustaining the natural attenuation process. PMID:28790991

Systemic Induction of the Defensin and Phytoalexin Pisatin Pathways in Pea (Pisum sativum) against Aphanomyces euteiches by Acetylated and Nonacetylated Oligogalacturonides.

PubMed

Selim, Sameh; Sanssené, Jean; Rossard, Stéphanie; Courtois, Josiane

2017-06-19

Oligogalacturonides (OGs) are known for their powerful ability to stimulate the plant immune system but little is known about their mode of action in pea ( Pisum sativum ). In the present study, we investigated the elicitor activity of two fractions of OGs, with polymerization degrees (DPs) of 2-25, in pea against Aphanomyces euteiches . One fraction was nonacetylated (OGs - Ac) whereas the second one was 30% acetylated (OGs + Ac). OGs were applied by injecting the upper two rachises of the plants at three- and/or four-weeks-old. Five-week-old roots were inoculated with 10⁵ zoospores of A. euteiches . The root infection level was determined at 7, 10 and 14 days after inoculation using the quantitative real-time polymerase chain reaction (qPCR). Results showed significant root infection reductions namely 58, 45 and 48% in the plants treated with 80 µg OGs + Ac and 59, 56 and 65% with 200 µg of OGs - Ac. Gene expression results showed the upregulation of genes involved in the antifungal defensins, lignans and the phytoalexin pisatin pathways and a priming effect in the basal defense, SA and ROS gene markers as a response to OGs. The reduction of the efficient dose in OGs + Ac is suggesting that acetylation is necessary for some specific responses. Our work provides the first evidence for the potential of OGs in the defense induction in pea against Aphanomyces root rot.

Effect of indomethacin on surface treatment and intracanal dressing of replanted teeth in dogs.

PubMed

Zanetta-Barbosa, Darceny; Moura, Camilla Christian Gomes; Machado, Juliana Reis; Crema, Virginia Oliveira; Lima, Cirilo Antônio de Paula; de Carvalho, Antônio Cesar Perry

2014-01-01

This study evaluated the healing process of teeth replanted after root treatment and intracanal dressing with indomethacin alone or indomethacin with calcium hydroxide (Ca[OH]2). Through a case-control study, 24 teeth of 6 adult dogs were extracted, dried, and divided into 4 groups according to the root surface treatment protocols performed before replantation and the intracanal medication used after replantation. In group 1 (negative control), root surfaces were treated by immersion in a 0.9% saline solution and then replanted. In the other groups, the roots were immersed for 10 minutes in Ca(OH)2 (group 2), indomethacin (group 3), or a solution of indomethacin and Ca(OH)2 (group 4). After 2 weeks, group 1 teeth were subjected to single-visit root canal treatment and obturation with gutta-percha and sealer consisting of zinc oxide and eugenol. The teeth in the other groups were subjected to intracanal dressing with the same material used for immersion. After an additional period of 28 weeks, the animals were euthanized and the jaws containing the replanted teeth were processed for histologic analysis. Histometric values were statistically analyzed, with significance set at a P value less than or equal to .05. Group 1 exhibited significantly more normal periodontium than group 4 (P = .02). Total resorption was greater in group 4 than in group 1 (P = .02). No statistically significant difference in the percentage of surface resorption or in total inactive resorption was observed between the groups. The findings of this study suggest that intracanal dressing and topical root treatment with Ca(OH)2 with or without indomethacin is not recommended for teeth dried for 50 minutes, but the use of indomethacin alone as root surface treatment for delayed tooth replantation deserves further study using longer drying periods. In addition, the present results suggest that a single-visit root canal, performed up to 2 weeks after replantation, might be indicated for teeth dried for up to 50 minutes. Copyright © 2014 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

Incorporation of a Cumulus Fraction Scheme in the GRAPES_Meso and Evaluation of Its Performance

NASA Astrophysics Data System (ADS)

Zheng, X.

2016-12-01

Accurate simulation of cloud cover fraction is a key and difficult issue in numerical modeling studies. Preliminary evaluations have indicated that cloud fraction is generally underestimated in GRAPES_Meso simulations, while the cloud fraction scheme (CFS) of ECMWF can provide more realistic results. Therefore, the ECMWF cumulus fraction scheme is introduced into GRAPES_Meso to replace the original CFS, and the model performance with the new CFS is evaluated based on simulated three-dimensional cloud fractions and surface temperature. Results indicate that the simulated cloud fractions increase and become more accurate with the new CFS; the simulation for vertical cloud structure has improved too; errors in surface temperature simulation have decreased. The above analysis and results suggest that the new CFS has a positive impact on cloud fraction and surface temperature simulation.

Effects of EDTA gel preconditioning of periodontally affected human root surfaces on chlorhexidine substantivity - an SEM study.

PubMed

Gamal, Ahmed Y; Mailhot, Jason M

2007-09-01

Infection control is an important requirement during the early stages of periodontal healing. This study was performed to assess the preconditioning effect of EDTA gel on chlorhexidine (CHX) substantivity to periodontally involved root surfaces. Eighty patients with severe chronic periodontitis were enrolled in this study. Following cause-related therapy, patients were divided randomly into four groups. Each group consisted of 20 subjects with one tooth that was diagnosed as hopeless and designated for extraction. In group 1 (G1), selected periodontal pockets were filled with a placebo gel in a silica base for 2 minutes. Exposed roots in group 2 (G2) were etched for 2 minutes with a neutral EDTA conditioning agent, followed by pocket fill with the placebo gel. Pockets in group 3 (G3) were filled with 0.12% CHX digluconate gel in a silica base. Exposed roots in group 4 (G4) were etched for 2 minutes with a neutral EDTA conditioning agent, followed by pocket fill with the CHX gel. Four teeth from each group were extracted immediately and at 3, 12, 24, and 48 hours for SEM evaluation. G1 and G2 specimens showed no evidence of silica adherent to any of the examined root surfaces. At 3 hours following CHX gel application, G3 specimens showed marked reduction in CHX-coated silica. At 24 and 48 hours following EDTA and CHX gel application, G4 specimens demonstrated adherent CHX-coated silica particles despite the reclogging of the tubule orifices. EDTA and CHX gel root conditioning is a valuable regimen that improves CHX substantivity to periodontally involved root surfaces.

A Physiological and Behavioral Mechanism for Leaf Herbivore-Induced Systemic Root Resistance1[OPEN

PubMed Central

Erb, Matthias; Robert, Christelle A.M.; Marti, Guillaume; Lu, Jing; Doyen, Gwladys R.; Villard, Neil; Barrière, Yves; Wolfender, Jean-Luc; Turlings, Ted C.J.

2015-01-01

Indirect plant-mediated interactions between herbivores are important drivers of community composition in terrestrial ecosystems. Among the most striking examples are the strong indirect interactions between spatially separated leaf- and root-feeding insects sharing a host plant. Although leaf feeders generally reduce the performance of root herbivores, little is known about the underlying systemic changes in root physiology and the associated behavioral responses of the root feeders. We investigated the consequences of maize (Zea mays) leaf infestation by Spodoptera littoralis caterpillars for the root-feeding larvae of the beetle Diabrotica virgifera virgifera, a major pest of maize. D. virgifera strongly avoided leaf-infested plants by recognizing systemic changes in soluble root components. The avoidance response occurred within 12 h and was induced by real and mimicked herbivory, but not wounding alone. Roots of leaf-infested plants showed altered patterns in soluble free and soluble conjugated phenolic acids. Biochemical inhibition and genetic manipulation of phenolic acid biosynthesis led to a complete disappearance of the avoidance response of D. virgifera. Furthermore, bioactivity-guided fractionation revealed a direct link between the avoidance response of D. virgifera and changes in soluble conjugated phenolic acids in the roots of leaf-attacked plants. Our study provides a physiological mechanism for a behavioral pattern that explains the negative effect of leaf attack on a root-feeding insect. Furthermore, it opens up the possibility to control D. virgifera in the field by genetically mimicking leaf herbivore-induced changes in root phenylpropanoid patterns. PMID:26430225

A wogonin-rich-fraction of Scutellaria baicalensis root extract exerts chondroprotective effects by suppressing IL-1β-induced activation of AP-1 in human OA chondrocytes

PubMed Central

Khan, Nazir M.; Haseeb, Abdul; Ansari, Mohammad Y.; Haqqi, Tariq M.

2017-01-01

Osteoarthritis (OA) is a common joint disorder with varying degrees of inflammation and sustained oxidative stress. The root extract of Scutellaria baicalensis (SBE) has been used for the treatment of inflammatory and other diseases. Here, we performed activity-guided HPLC-fractionation of SBE, identified the active ingredient(s) and investigated its chondroprotective potential. We found that the Wogonin containing fraction-4 (F4) was the most potent fraction based on its ability to inhibit ROS production and the suppression of catabolic markers including IL-6, COX-2, iNOS, MMP-3, MMP-9, MMP-13 and ADAMTS-4 in IL-1β-treated OA chondrocytes. OA chondrocytes treated with F4 in the presence of IL-1β showed significantly enhanced expression of anabolic genes ACAN and COL2A1. In an in vitro model of cartilage degradation treatment with F4 inhibited s-GAG release from IL-1β-treated human cartilage explants. The inhibitory effect of F4 was not mediated through the inhibition of MAPKs and NF-κB activation but was mediated through the suppression of c-Fos/AP-1 activity at transcriptional and post transcriptional levels in OA chondrocytes. Purified Wogonin mimicked the effects of F4 in IL-1β-stimulated OA chondrocytes. Our data demonstrates that a Wogonin-rich fraction of SBE exert chondroprotective effects through the suppression of c-Fos/AP-1 expression and activity in OA chondrocytes under pathological conditions. PMID:28256567

Three year field test of a plant growth promoting rhizobacteria enhanced phytoremediation system at a land farm for treatment of hydrocarbon waste.

PubMed

Gurska, Jolanta; Wang, Wenxi; Gerhardt, Karen E; Khalid, Aaron M; Isherwood, David M; Huang, Xiao-Dong; Glick, Bernard R; Greenberg, Bruce M

2009-06-15

Phytoremediation of total petroleum hydrocarbons (TPH) has the potential to be a sustainable waste management technology if it can be proven to be effective in the field. Over the past decade, our laboratory has developed a system which utilizes plant growth promoting rhizobacteria (PGPR) enhanced phytoremediation (PEP) that, following extensive greenhouse testing, was shown to be effective at remediating TPH from soils. This system consists of physical soil manipulation and plant growth following seed inoculation with PGPR. PGPR elicit biomass increases, particularly in roots, by minimizing plant stress in highly contaminated soils. Extensive development of the root system enhances degradation of contaminants by the plants and supports an active rhizosphere that effectively promotes TPH degradation by a broad microbial consortium. Following promising greenhouse trials, field tests of PEP were performed over a period of three years at a Southern Ontario site (approximately 130 g kg(-1) TPH) used for land farming of refinery hydrocarbon waste for many years. The low molecular weight fractions (the Canadian Council of Ministers of the Environment (CCME) fractions 1 and 2) were removed through land farming and bioremediation; the high molecular weight, recalcitrant fractions (CCME fractions 3 and 4) remained at high levels in the soil. Using PEP, we substantially remediated fractions 3 and 4, and lowered TPH from 130 g kg(-1) to approximately 50 g kg(-1) over a three year period. The amount of plant growth and extent of oil remediation were consistently enhanced by PGPR.

Challenges to estimating whole forest root biomass with ground penetrating radar

NASA Astrophysics Data System (ADS)

Butnor, J. R.

2016-12-01

Over the past two decades, substantial technical advances have been made in detecting tree roots with ground penetrating radar (GPR). Under favorable soil dielectric conditions, root location, depth, diameter and mass estimates are possible in the field. With careful notation of survey lines, three dimensional reconstructions of root architecture may also be achieved. The technique has been very useful for quantifying lateral root biomass in silvicultural studies, but is not yet a standalone technique for estimating root biomass in forests. The purpose of this presentation is to highlight the limitations of GPR in the field to stimulate discussion on how to overcome these challenges. Under field conditions, surface-based antennas with frequencies of 400 to 1500 MHz cannot detect fine roots (<2 mm diameter), vertical taproots, below-stump mass, decayed roots or separate roots by species. Higher frequency antennas designed for concrete inspection are available, but penetration through forest soils would be marginal. Over half of the root mass in many Pinus species is in the taproot which is undetectable in part or whole by GPR. This presents challenges to stand-level quantification as whole classes of biomass and structures are not reliably detected. Lack of automation of data processing and interpretation steps currently makes data analysis arduous and in some cases subject to interpretation by an expert user. Forests have a high degree of heterogeneity in surface conditions (e.g., holes, soil moisture, stems, woody and herbaceous plants) that may prevent antennas from coupling with the surface to propagate EM waves and receive reflections. What is the potential for open source data analysis programs to be developed and shared? How will new digital, multi-frequency antennas improve resolution? Can air launched antennas be developed that have both the depth penetration and resolution to detect roots? Are purpose-designed bore hole antenna needed for imaging taproots?

Morphological Changes Of The Root Surface And Fracture Resistance After Treatment Of Root Fracture By CO2 Laser And Glass Ionomer Or Mineral Trioxide Aggregates

NASA Astrophysics Data System (ADS)

Badr, Y. A.; Abd El-Gawad, L. M.; Ghaith, M. E.

2009-09-01

This in vitro study evaluates the morphological changes of the root surface and fracture resistance after treatment of root cracks by CO2 laser and glass Ionomer or mineral trioxide aggregates (MTA). Fifty freshly extracted human maxillary central incisor teeth with similar dimension were selected. Crowns were sectioned at the cemento-enamel junction, and the lengths of the roots were adjusted to 13 mm. A longitudinal groove with a dimension of 1×5 mm2 and a depth of 1.5 mm was prepared by a high speed fissure bur on the labial surface of the root. The roots were divided into 5 groups: the 10 root grooves in group 1 were remained unfilled and were used as a control group. The 10 root grooves in group 2 were filled with glass Ionomer, 10 root grooves in group 3 were filled with MTA, the 10 root grooves in group 4 were filled with glass Ionomer and irradiated by CO2 laser and the 10 root grooves in group 5 were filled with MTA and irradiated with CO2 laser. Scanning electron microscopy was performed for two samples in each group. Tests for fracture strength were performed using a universal testing machine and a round tip of a diameter of 4 mm. The force was applied vertically with a constant speed of 1 mm min 1. For each root, the force at the time of fracture was recorded in Newtons. Results were evaluated statistically with ANOVA and Turkey's Honestly Significant Difference (HSD) tests. SEM micrographs revealed that the melted masses and the plate-like crystals formed a tight Chemical bond between the cementum and glass Ionomer and melted masses and globular like structure between cementum and MTA. The mean fracture resistance was the maximum fracture resistance in group 5 (810.8 N). Glass Ionomer and MTA with the help of CO2 laser can be an alternative to the treatment of tooth crack or fracture. CO2 laser increase the resistance of the teeth to fracture.

In vitro and clinical evaluation of optical coherence tomography for the detection of subgingival calculus and root cementum.

PubMed

Tsubokawa, Masaki; Aoki, Akira; Kakizaki, Sho; Taniguchi, Yoichi; Ejiri, Kenichiro; Mizutani, Koji; Koshy, Geena; Akizuki, Tatsuya; Oda, Shigeru; Sumi, Yasunori; Izumi, Yuichi

2018-05-24

This study evaluated the effectiveness of swept-source optical coherence tomography (ss-OCT) for detecting calculus and root cementum during periodontal therapy. Optical coherence tomography (OCT) images were taken before and after removal of subgingival calculus from extracted teeth and compared with non-decalcified histological sections. Porcine gingival sheets of various thicknesses were applied to the root surfaces of extracted teeth with calculus and OCT images were taken. OCT images were also taken before and after scaling and root planing (SRP) in human patients. In vitro, calculus was clearly detected as a white-gray amorphous structure on the root surface, which disappeared after removal. Cementum was identified as a thin, dark-gray layer. The calculus could not be clearly observed when soft tissues were present on the root surface. Clinically, supragingival calculus and cementum could be detected clearly with OCT, and subgingival calculus in the buccal cervical area of the anterior and premolar teeth was identified, which disappeared after SRP. Digital processing of the original OCT images was useful for clarifying the calculus. In conclusion, ss-OCT showed potential as a periodontal diagnostic tool for detecting cementum and subgingival calculus, although the practical applications of subgingival imaging remain limited.

Graviresponsiveness of surgically altered primary roots of Zea mays

NASA Technical Reports Server (NTRS)

Maimon, E.; Moore, R.

1991-01-01

We examined the gravitropic responses of surgically altered primary roots of Zea mays to determine the route by which gravitropic inhibitors move from the root tip to the elongating zone. Horizontally oriented roots, from which a 1-mm-wide girdle of epidermis plus 2-10 layers of cortex were removed from the apex of the elongating zone, curve downward. However, curvature occurred only apical to the girdle. Filling the girdle with mucilage-like material transmits curvature beyond the girdle. Vertically oriented roots with a half-girdle' (i.e. the epidermis and 2-10 layers of the cortex removed from half of the circumference of the apex of the elongating zone) curve away from the girdle. Inserting the half-girdle at the base of the elongating zone induces curvature towards the girdle. Filling the half-circumference girdles with mucilage-like material reduced curvature significantly. Stripping the epidermis and outer 2-5 layers of cortex from the terminal 1.5 cm of one side of a primary root induces curvature towards the cut, irrespective of the root's orientation to gravity. This effect is not due to desiccation since treated roots submerged in water also curved towards their cut surface. Coating a root's cut surface with a mucilage-like substance minimizes curvature. These results suggest that the outer cell-layers of the root, especially the epidermis, play an important role in root gravicurvature, and the gravitropic signals emanating from the root tip can move apoplastically through mucilage.

Compensatory Root Water Uptake of Overlapping Root Systems

NASA Astrophysics Data System (ADS)

Agee, E.; Ivanov, V. Y.; He, L.; Bisht, G.; Shahbaz, P.; Fatichi, S.; Gough, C. M.; Couvreur, V.; Matheny, A. M.; Bohrer, G.

2015-12-01

Land-surface models use simplified representations of root water uptake based on biomass distributions and empirical functions that constrain water uptake during unfavorable soil moisture conditions. These models fail to capture the observed hydraulic plasticity that allows plants to regulate root hydraulic conductivity and zones of active uptake based on local gradients. Recent developments in root water uptake modeling have sought to increase its mechanistic representation by bridging the gap between physically based microscopic models and computationally feasible macroscopic approaches. It remains to be demonstrated whether bulk parameterization of microscale characteristics (e.g., root system morphology and root conductivity) can improve process representation at the ecosystem scale. We employ the Couvreur method of microscopic uptake to yield macroscopic representation in a coupled soil-root model. Using a modified version of the PFLOTRAN model, which represents the 3-D physics of variably saturated soil, we model a one-hectare temperate forest stand under natural and synthetic climatic forcing. Our results show that as shallow soil layers dry, uptake at the tree and stand level shift to deeper soil layers, allowing the transpiration stream demanded by the atmosphere. We assess the potential capacity of the model to capture compensatory root water uptake. Further, the hydraulic plasticity of the root system is demonstrated by the quick response of uptake to rainfall pulses. These initial results indicate a promising direction for land surface models in which significant three-dimensional information from large root systems can be feasibly integrated into the forest scale simulations of root water uptake.

Analysis of the relationship between rusty root incidences and soil properties in Panax ginseng

NASA Astrophysics Data System (ADS)

Wang, Q. X.; Xu, C. L.; Sun, H.; Ma, L.; Li, L.; Zhang, D. D.; Zhang, Y. Y.

2016-08-01

Rusty root is a serious problem in ginseng cultivation that limits the production and quality of ginseng worldwide. The Changbai Mountains are the most famous area for ginseng cultivation in China. To clarify the relationship between rusty root and soil characteristics, physico-chemical properties and enzymatic activities of soil collected from five different fields in the Changbai Mountains were analyzed and a controlled experiment carried out by increasing the concentration of Fe (II). Soil bulk density, moisture, total iron (Fe) and total manganese (Mn) concentrations and polyphenol oxidase (PPO) activity were significantly higher in rusty root than healthy root groups (two-sample test, P<0.05 or P<0.01), respectively. Pearson test showed that there was a significant positive correlation between rusty root index and pH, N, Fe, Mn, Al, Zn and Ca of soil samples collected from fields (P<0.05 or P<0.01), and a significant positive correlation also occurred between rusty root index and Fe (II) added to soil in Fe (II) inducing rusty root (P<0.01). Physiological factors may be very important roles giving rise to ginseng rusty root. Fe (III) reduction and Fe (II) oxidation could be important in increasing the incidence of rusty root. Soil moisture and bulk density of non-rhizosphere soil not attached to the root surface, and pH, N and PPO content of rhizosphere soils attached to the root surface were heavily involved in the reduction, oxidation and sequestration of metal ions.

On the use of antibiotics to reduce rhizoplane microbial populations in root physiology and ecology investigations

NASA Technical Reports Server (NTRS)

Smart, D. R.; Ferro, A.; Ritchie, K.; Bugbee, B. G.

1995-01-01

No straightforward method exists for separating the proportion of ion exchange and respiration due to rhizoplane microbial organisms from that of root ion exchange and respiration. We examined several antibiotics that might be used for the temporary elimination of rhizoplane bacteria from hydroponically grown wheat roots (Triticum aestivum cv. Veery 10). Each antibiotic was tested for herbicidal activity and plate counts were used to enumerate bacteria and evaluate antibiotic kinetics. Only lactam antibiotics (penicillins and cephalosporins) did not reduce wheat growth rates. Aminoglycosides, the pyrimidine trimethoprim, colistin and rifampicin reduced growth rates substantially. Antibiotics acted slowly, with maximum reductions in rhizoplane bacteria occurring after more than 48 h of exposure. Combinations of nonphytotoxic antibiotics reduced platable rhizoplane bacteria by as much as 98%; however, this was generally a reduction from about 10(9) to 10(6) colony forming units per gram of dry root mass, so that many viable bacteria remained on root surfaces. We present evidence which suggests that insufficient bacterial biomass exists on root surfaces of nonstressed plants grown under well-aerated conditions to quantitatively interfere with root nitrogen absorption measurements.

Surface soil root response to season of repeated fire in a young longleaf pine plantation

Treesearch

Mary Anne Sword Sayer; James D. Haywood

2012-01-01

The potential exists for interaction between naturally high soil bulk density and low soil water content to create root-growth limiting soil strengths. This problem is commonly remedied by soil structural attributes, old root channels and other perturbations, and periods of wetness during which soil strength is favorable for root elongation. Because the application and...

Planetary boundary layer height over the Indian subcontinent: Variability and controls with respect to monsoon

NASA Astrophysics Data System (ADS)

Sathyanadh, Anusha; Prabhakaran, Thara; Patil, Chetana; Karipot, Anandakumar

2017-10-01

Planetary boundary layer (PBL) height characteristics over the Indian sub-continent at diurnal to seasonal scales and its controlling factors in relation to monsoon are investigated. The reanalysis (Modern Era Retrospective analysis for Research and Applications, MERRA) PBL heights (PBLH) used for the study are validated against those derived from radiosonde observations and radio occultation air temperature and humidity profiles. The radiosonde observations include routine India Meteorological Department observations at two locations (coastal and an inland) for one full year and campaign based early afternoon radiosonde observations at six inland locations over the study region for selected days from May-September 2011. The temperature and humidity profiles from radio occultations spread over the sub-continent at irregular timings during the year 2011. The correlations and root mean square errors are in the range 0.74-0.83 and 407 m-643 m, respectively. Large pre-monsoon, monsoon and post-monsoon variations in PBL maximum height (1000 m-4000 m), time of occurrence of maximum height (11:00 LST-17:00 LST) and growth rate (100 to 400 m h- 1) are noted over the land, depending on geographical location and more significantly on the moisture availability which influences the surface sensible and latent heat fluxes. The PBLH variations associated with active-break intra-seasonal monsoon oscillations are up to 1000 m over central Indian locations. Inter relationship between the PBLH and the controlling factors, i.e. Evaporative Fraction, net radiation, friction velocity, surface Richardson number, and scalar diffusivity fraction, show significant variation between dry and wet PBL regimes, which also varies with geographical location. Evaporative fraction has dominant influence on the PBLH over the region. Enhanced entrainment during monsoon contributes to reduction in PBLH, whereas the opposite effect is noted during dry period. Linear regression, cross wavelet and Analysis of Variance (ANOVA) methods are used to elucidate the role of controlling factors and interactions on PBLH in relation to monsoon.

Evapotranspiration flux partitioning using an Iso-SPAC model in a temperate grassland ecosystem

NASA Astrophysics Data System (ADS)

Wang, P.

2014-12-01

To partition evapotranspiration (ET) into soil evaporation and vegetation transpiration (T), a new numerical Iso-SPAC (coupled heat, water with isotopic tracer in Soil-Plant-Atmosphere-Continuum) model was developed and applied to a temperate-grassland ecosystem in central Japan. Several models of varying complexity have been tested with the aim of obtaining the close to true value for the isotope composition of leaf water and transpiration flux. The agreement between the model predictions and observations demonstrates that the Iso-SPAC model with a steady-state assumption for transpiration flux can reproduce seasonal variations of all the surface energy balance components，leaf and ground surface temperature as well as isotope data (canopy foliage and ET flux). This good performance was confirmed not only at diurnal timescale but also at seasonal timescale. Thus, although the non-steady-state behavior of isotope budget in a leaf and isotopic diffusion between leaf and stem or root is exactly important, the steady-state assumption is practically acceptable for seasonal timescale as a first order approximation. Sensitivity analysis both in physical flux part and isotope part suggested that T/ET is relatively insensitive to uncertainties/errors in assigned model parameters and measured input variables, which illustrated the partitioning validity. Estimated transpiration fractions using isotope composition in ET flux by Iso-SPAC model and Keeling plot are generally in good agreement, further proving validity of the both approaches. However, Keeling plot approach tended to overestimate the fraction during an early stage of glowing season and a period just after clear cutting. This overestimation is probably due to insufficient fetch and influence of transpiration from upwind forest. Consequently, Iso-SPAC model is more reliable than Keeling plot approach in most cases.The T/ET increased with grass growth, and the sharp reduction caused by clear cutting was well reflected. The transpiration fraction ranges from 0.02 to 0.99 during growing seasons, and the mean value was 0.75 with a standard deviation of 0.24.

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

NASA Astrophysics Data System (ADS)

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 <0.5% - on the soil / 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

[Phytoremediation of Petroleum Contaminated Soils with Iris pseudacorus L. and the Metabolic Analysis in Roots].

PubMed

Wang, Ya-nan; Cheng, Li-juan; Zhou, Qi-xing

2016-04-15

In this study, we performed a greenhouse pot-culture experiment to investigate the potential of a wild ornamental plant Iris pseudacorus L. in remediating petroleum contaminated soils from the Dagang Oilfield in Tianjin, China. The results suggested that Iris pseudacorus L. had great resistance to ≤ 40,000 mg · kg(⁻¹ of total petroleum hydrocarbons (TPHs). The removal rate of TPHs with concentrations of 10,000 mg · kg⁻¹, 20,000 mg · kg⁻¹ and 40,000 mg · kg⁻¹ in soils by Iris pseudacorus L. was 42.1%, 33.1% 31.2%, respectively, much higher than those in the corresponding controls (31.8%, 21.3% 11.9%, respectively) (P < 0.05). The root specific surface area of Iris pseudacorus L. was determined by the root scanner. The results suggested that TPHs with concentrations of 10,000 mg · kg⁻¹, 20,000 mg · kg⁻¹ and 40,000 mg · kg⁻¹ in soils increased the root specific surface area comparing with the controls. Additionally, the metabolic analysis showed that root metabolism changed to different degrees under the stress of TPHs, and the levels or species of metabolites had a significant change (P < 0.001). Furthermore, the results showed that 5 of 11 metabolites (VIP value > 1.2) with the root specific surface area from the PLS-DA model analysis, including ethanedioic acid, lactic acid, 2-butenedioic acid, phosphate and propanedioic acid, were positively correlated with the root specific surface area, but the others, gluconic acid, uridine, butanoic acid, maltose, 9,12-octadecadienoic acid, phenylalanine, were negatively correlated with it. In conclusion, using Iris pseudacorus L. to remediate petroleum contaminated soils is feasible, and the metabolic analysis in roots is useful to better understand the metabolic response of plants exposure to petroleum contaminated soils, and then reveals its remediated mechanisms.

Apices of maxillary premolars observed by swept source optical coherence tomography

NASA Astrophysics Data System (ADS)

Ebihara, Arata; Iino, Yoshiko; Yoshioka, Toshihiko; Hanada, Takahiro; Sunakawa, Mitsuhiro; Sumi, Yasunori; Suda, Hideaki

2015-02-01

Apicoectomy is performed for the management of apical periodontitis when orthograde root canal treatment is not possible or is ineffective. Prior to the surgery, cone beam computed tomography (CBCT) examination is often performed to evaluate the lesion and the adjacent tissues. During the surgical procedure, the root apex is resected and the resected surface is usually observed under dental operating microscope (DOM). However, it is difficult to evaluate the details and the subsurface structure of the root using CBCT and DOM. A new diagnostic system, swept source optical coherence tomography (SS-OCT), has been developed to observe the subsurface anatomical structure. The aim of this study was to observe resected apical root canals of human maxillary premolars using SS-OCT and compare the findings with those observed using CBCT and DOM. Six extracted human maxillary premolars were used. After microfocus computed tomography (Micro CT; for gold standard) and CBCT scanning of the root, 1 mm of the apex was cut perpendicular to the long axis of the tooth. Each resected surface was treated with EDTA, irrigated with saline solution, and stained with methylene blue dye. The resected surface was observed with DOM and SS-OCT. This sequence was repeated three times. The number of root canals was counted and statistically evaluated. There was no significant difference in the accuracy of detecting root canals among CBCT, DOM and SS-OCT (p > 0.05, Wilcoxon test). Because SS-OCT can be used in real time during surgery, it would be a useful tool for observing resected apical root canals.

Monitoring the colonization of sugarcane and rice plants by the endophytic diazotrophic bacterium Gluconacetobacter diazotrophicus marked with gfp and gusA reporter genes.

PubMed

Rouws, L F M; Meneses, C H S G; Guedes, H V; Vidal, M S; Baldani, J I; Schwab, S

2010-09-01

To evaluate the colonization process of sugarcane plantlets and hydroponically grown rice seedlings by Gluconacetobacter diazotrophicus strain PAL5 marked with the gusA and gfp reporter genes. Sugarcane plantlets inoculated in vitro with PAL5 carrying the gfp::gusA plasmid pHRGFPGUS did not present green fluorescence, but beta-glucuronidase (GUS)-stained bacteria could be observed inside sugarcane roots. To complement this existing inoculation methodology for micropropagated sugarcane with a more rapid colonization assay, we employed hydroponically grown gnotobiotic rice seedlings to study PAL5-plant interaction. PAL5 could be isolated from the root surface (10(8) CFU g(-1)) and from surface-disinfected root and stem tissues (10(4) CFU g(-1)) of inoculated plants, suggesting that PAL5 colonized the internal plant tissues. Light microscopy confirmed the presence of bacteria inside the root tissue. After inoculation of rice plantlets with PAL5 marked with the gfp plasmid pHRGFPTC, bright green fluorescent bacteria could be seen colonizing the rice root surface, mainly at the sites of lateral root emergence, at root caps and on root hairs. The plasmids pHRGFPGUS and pHRGFPTC are valid tools to mark PAL5 and monitor the colonization of micropropagated sugarcane and hydroponic rice seedlings. These tools are of use to: (i) study PAL5 mutants affected in bacteria-plant interactions, (ii) monitor plant colonization in real time and (iii) distinguish PAL5 from other bacteria during the study of mixed inoculants.

Catechol, a major component of smoke, influences primary root growth and root hair elongation through reactive oxygen species-mediated redox signaling.

PubMed

Wang, Ming; Schoettner, Matthias; Xu, Shuqing; Paetz, Christian; Wilde, Julia; Baldwin, Ian T; Groten, Karin

2017-03-01

Nicotiana attenuata germinates from long-lived seedbanks in native soils after fires. Although smoke signals have been known to break seed dormancy, whether they also affect seedling establishment and root development remains unclear. In order to test this, seedlings were treated with smoke solutions. Seedlings responded in a dose-dependent manner with significantly increased primary root lengths, due mainly to longitudinal cell elongation, increased numbers of lateral roots and impaired root hair development. Bioassay-driven fractionations and NMR were used to identify catechol as the main active compound for the smoke-induced root phenotype. The transcriptome analysis revealed that mainly genes related to auxin biosynthesis and redox homeostasis were altered after catechol treatment. However, histochemical analyses of reactive oxygen species (ROS) and the inability of auxin applications to rescue the phenotype clearly indicated that highly localized changes in the root's redox-status, rather than in levels of auxin, are the primary effector. Moreover, H 2 O 2 application rescued the phenotype in a dose-dependent manner. Chemical cues in smoke not only initiate seed germination, but also influence seedling root growth; understanding how these cues work provides new insights into the molecular mechanisms by which plants adapt to post-fire environments. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

7 CFR 201.56-10 - Spurge family, Euphorbiaceae.

Code of Federal Regulations, 2011 CFR

2011-01-01

... dicot. (2) Food reserves: Cotyledons, which are thin and leaf-like; endosperm (fleshy food-storage... the cotyledons, endosperm, and epicotyl above the soil surface. (4) Root system: A primary root, with secondary roots usually developing within the test period. (b) Abnormal seedling description. (1) Cotyledons...

7 CFR 201.56-10 - Spurge family, Euphorbiaceae.

Code of Federal Regulations, 2010 CFR

2010-01-01

... dicot. (2) Food reserves: Cotyledons, which are thin and leaf-like; endosperm (fleshy food-storage... the cotyledons, endosperm, and epicotyl above the soil surface. (4) Root system: A primary root, with secondary roots usually developing within the test period. (b) Abnormal seedling description. (1) Cotyledons...

Measurement of Net Fluxes of Ammonium and Nitrate at the Surface of Barley Roots Using Ion-Selective Microelectrodes 1

PubMed Central

Henriksen, Gordon H.; Raman, D. Raj; Walker, Larry P.; Spanswick, Roger M.

1992-01-01

Net fluxes of NH4+ and NO3− into roots of 7-day-old barley (Hordeum vulgare L. cv Prato) seedlings varied both with position along the root axis and with time. These variations were not consistent between replicate plants; different roots showed unique temporal and spatial patterns of uptake. Axial scans of NH4+ and NO3− net fluxes were conducted along the apical 7 centimeters of seminal roots of intact barley seedlings in solution culture using ion-selective microelectrodes in the unstirred layer immediately external to the root surface. Theoretically derived relationships between uptake and concentration gradients, combined with experimental observations of the conditions existing in our experimental system, permitted evaluation of the contribution of bulk water flow to ion movement in the unstirred layer, as well as a measure of the spatial resolution of the microelectrode flux estimation technique. Finally, a method was adopted to assess the accuracy of this technique. PMID:16668947

[Interaction of surface-active base with fraction of membrane-bound Williams's protons].

PubMed

Iaguzhinskiĭ, L S; Motovilov, K A; Volkov, E M; Eremeev, S A

2013-01-01

In the process of mitochondrial respiratory H(+)-pumps functioning, the fraction membrane-bound protons (R-protons), which have an excess of free energy is formed. According to R.J. Williams this fraction is included as energy source in the reaction of ATP synthesis. Previously, in our laboratory was found the formation of this fraction was found in the mitochondria and on the outer surface of mitoplast. On the mitoslast model we strictly shown that non-equilibrium R-proton fraction is localized on the surface of the inner mitochondrial membrane. In this paper a surface-active compound--anion of 2,4,6-trichloro-3-pentadecylphenol (TCP-C15) is described, which selectively interacts with the R-protons fraction in mitochondria. A detailed description of the specific interaction of the TCP-C15 with R-protons fraction in mitochondria is presented. Moreover, in this work it was found that phosphate transport system reacts with the R-protons fraction in mitochondria and plays the role of the endogenous volume regulation system of this fraction. The results of experiments are discussed in the terms of a local coupling model of the phosphorylation mechanism.

Endophytic colonization of olive roots by the biocontrol strain Pseudomonas fluorescens PICF7.

PubMed

Prieto, Pilar; Mercado-Blanco, Jesús

2008-05-01

Confocal microscopy combined with three-dimensional olive root tissue sectioning was used to provide evidence of the endophytic behaviour of Pseudomonas fluorescens PICF7, an effective biocontrol strain against Verticillium wilt of olive. Two derivatives of the green fluorescent protein (GFP), the enhanced green and the red fluorescent proteins, have been used to visualize simultaneously two differently fluorescently tagged populations of P. fluorescens PICF7 within olive root tissues at the single cell level. The time-course of colonization events of olive roots cv. Arbequina by strain PICF7 and the localization of tagged bacteria within olive root tissues are described. First, bacteria rapidly colonized root surfaces and were predominantly found in the differentiation zone. Thereafter, microscopy observations showed that PICF7-tagged populations eventually disappeared from the root surface, and increasingly colonized inner root tissues. Localized and limited endophytic colonization by the introduced bacteria was observed over time. Fluorescent-tagged bacteria were always visualized in the intercellular spaces of the cortex region, and no colonization of the root xylem vessels was detected at any time. To the best of our knowledge, this is the first time this approach has been used to demonstrate endophytism of a biocontrol Pseudomonas spp. strain in a woody host such as olive using a nongnotobiotic system.

Root hair development in grasses and cereals (Poaceae).

PubMed

Dolan, Liam

2017-08-01

Root hairs are tubular, cellular outgrowths of epidermal cells that extend from the root surface into the soil. Root hairs tether root systems to their growth substrate, take up inorganic nutrients and water, and interact with the soil microflora. At maturity, the root epidermis comprises two cell types; cells with root hairs and hairless epidermal cells. These two cell types alternate with each other along longitudinal files in grasses and cereals (Poaceae). While the mechanism by which this alternating pattern develops is unknown, the later stages of root hair differentiation are controlled by a conserved mechanism that promotes root hair development among angiosperms. Crown Copyright © 2017. Published by Elsevier Ltd. All rights reserved.

Combating photooxidative stress in green hairy roots of Daucus carota cultivated under light irradiation.

PubMed

Mukherjee, Chiranjit; Sircar, Debabrata; Chatterjee, Moniya; Das, Sampa; Mitra, Adinpunya

2014-01-15

The light-dependent generation of active oxygen species, which can disrupt normal metabolic process of plant, is termed as photo-oxidative stress. Plants are equipped with enzymatic and non-enzymatic antioxidative defence system to reduce the effect of such stress. Hairy root culture of Daucus carota when cultivated under continuous illumination (250 μmol m(-2)s(-1)) turned green. To know the reason behind that and photo-oxidative stress response in green hairy roots, activities of several antioxidant enzymes were measured. When compared with normal hairy roots, green hairy roots showed an enhanced superoxide dismutase (SOD) activity. Treatment with a SOD inhibitor diethyldithiocarbamate led to suppression of SOD activity in a concentration-dependent manner in green hairy roots. Interestingly, SOD-suppressed root showed three-fold enhanced caffeic acid glucoside accumulation in the soluble fraction as compared to untreated ones. While ascorbate peroxidase activity showed marginal increase in green hairy roots, a decrease in the activities of guaiacol peroxidase and catalase were observed. SDS-PAGE of crude protein profile from green hairy roots showed a distinct band, which was absent in normal hairy roots. MALDI-TOF-MS/MS analysis of the extracted protein confirmed it as the large subunit of RuBisCO. RT-PCR based expression analysis of betaine aldehyde dehydrogenase showed enhanced transcript levels in green hairy roots as compared to normal hairy roots, whereas reverse trends were observed with the transcripts accumulation for phenylalanine ammonia-lyase and chalcone synthase. These findings corroborate with the in vitro BADH activities in hairy roots, and thus indicate an important role of this stress enzyme in combating photo-oxidative stress in green hairy roots upon continuous light exposure. Copyright © 2013 Elsevier GmbH. All rights reserved.

Effect of arabinogalactan proteins from the root caps of pea and Brassica napus on Aphanomyces euteiches zoospore chemotaxis and germination.

PubMed

Cannesan, Marc Antoine; Durand, Caroline; Burel, Carole; Gangneux, Christophe; Lerouge, Patrice; Ishii, Tadashi; Laval, Karine; Follet-Gueye, Marie-Laure; Driouich, Azeddine; Vicré-Gibouin, Maïté

2012-08-01

Root tips of many plant species release a number of border, or border-like, cells that are thought to play a major role in the protection of root meristem. However, little is currently known on the structure and function of the cell wall components of such root cells. Here, we investigate the sugar composition of the cell wall of the root cap in two species: pea (Pisum sativum), which makes border cells, and Brassica napus, which makes border-like cells. We find that the cell walls are highly enriched in arabinose and galactose, two major residues of arabinogalactan proteins. We confirm the presence of arabinogalactan protein epitopes on root cap cell walls using immunofluorescence microscopy. We then focused on these proteoglycans by analyzing their carbohydrate moieties, linkages, and electrophoretic characteristics. The data reveal (1) significant structural differences between B. napus and pea root cap arabinogalactan proteins and (2) a cross-link between these proteoglycans and pectic polysaccharides. Finally, we assessed the impact of root cap arabinogalactan proteins on the behavior of zoospores of Aphanomyces euteiches, an oomycetous pathogen of pea roots. We find that although the arabinogalactan proteins of both species induce encystment and prevent germination, the effects of both species are similar. However, the arabinogalactan protein fraction from pea attracts zoospores far more effectively than that from B. napus. This suggests that root arabinogalactan proteins are involved in the control of early infection of roots and highlights a novel role for these proteoglycans in root-microbe interactions.

Effect of Arabinogalactan Proteins from the Root Caps of Pea and Brassica napus on Aphanomyces euteiches Zoospore Chemotaxis and Germination12[C][W

PubMed Central

Cannesan, Marc Antoine; Durand, Caroline; Burel, Carole; Gangneux, Christophe; Lerouge, Patrice; Ishii, Tadashi; Laval, Karine; Follet-Gueye, Marie-Laure; Driouich, Azeddine; Vicré-Gibouin, Maïté

2012-01-01

Root tips of many plant species release a number of border, or border-like, cells that are thought to play a major role in the protection of root meristem. However, little is currently known on the structure and function of the cell wall components of such root cells. Here, we investigate the sugar composition of the cell wall of the root cap in two species: pea (Pisum sativum), which makes border cells, and Brassica napus, which makes border-like cells. We find that the cell walls are highly enriched in arabinose and galactose, two major residues of arabinogalactan proteins. We confirm the presence of arabinogalactan protein epitopes on root cap cell walls using immunofluorescence microscopy. We then focused on these proteoglycans by analyzing their carbohydrate moieties, linkages, and electrophoretic characteristics. The data reveal (1) significant structural differences between B. napus and pea root cap arabinogalactan proteins and (2) a cross-link between these proteoglycans and pectic polysaccharides. Finally, we assessed the impact of root cap arabinogalactan proteins on the behavior of zoospores of Aphanomyces euteiches, an oomycetous pathogen of pea roots. We find that although the arabinogalactan proteins of both species induce encystment and prevent germination, the effects of both species are similar. However, the arabinogalactan protein fraction from pea attracts zoospores far more effectively than that from B. napus. This suggests that root arabinogalactan proteins are involved in the control of early infection of roots and highlights a novel role for these proteoglycans in root-microbe interactions. PMID:22645070

A new flavonoid glycoside from the root bark of Morus alba L.

PubMed

Park, Ji-Hae; Jung, Ye-Jin; Jung, Jae-Woo; Shrestha, Sabina; Lim, Dong Wook; Han, Daeseok; Baek, Nam-In

2014-01-01

A new guibourtinidol glycoside, (2R,3S)-guibourtinidol-3-O-α-d-apiofuranosyl-(1 → 6)-O-β-D-glucopyranoside (1), and three known compounds, quercetin 7-O-β-D-glucopyranoside (2), syringaresinol-4-O-β-D-glucopyranoside (3) and dehydrodiconiferyl alcohol 4,9'-di-O-β-D-glucopyranoside (4), were isolated from the root bark of Morus alba L. through repeated silica gel, octadecyl silica gel and Sephadex LH-20 column chromatography for the n-BuOH fraction. The chemical structure of the compounds was elucidated based on MS, infrared, 1D and 2D NMR spectroscopic data. Compounds 2-4 were also isolated for the first time from the root bark of M. alba L. in this study.

Computer-based video digitizer analysis of surface extension in maize roots: kinetics of growth rate changes during gravitropism

NASA Technical Reports Server (NTRS)

Ishikawa, H.; Hasenstein, K. H.; Evans, M. L.

1991-01-01

We used a video digitizer system to measure surface extension and curvature in gravistimulated primary roots of maize (Zea mays L.). Downward curvature began about 25 +/- 7 min after gravistimulation and resulted from a combination of enhanced growth along the upper surface and reduced growth along the lower surface relative to growth in vertically oriented controls. The roots curved at a rate of 1.4 +/- 0.5 degrees min-1 but the pattern of curvature varied somewhat. In about 35% of the samples the roots curved steadily downward and the rate of curvature slowed as the root neared 90 degrees. A final angle of about 90 degrees was reached 110 +/- 35 min after the start of gravistimulation. In about 65% of the samples there was a period of backward curvature (partial reversal of curvature) during the response. In some cases (about 15% of those showing a period of reverse bending) this period of backward curvature occurred before the root reached 90 degrees. Following transient backward curvature, downward curvature resumed and the root approached a final angle of about 90 degrees. In about 65% of the roots showing a period of reverse curvature, the roots curved steadily past the vertical, reaching maximum curvature about 205 +/- 65 min after gravistimulation. The direction of curvature then reversed back toward the vertical. After one or two oscillations about the vertical the roots obtained a vertical orientation and the distribution of growth within the root tip became the same as that prior to gravistimulation. The period of transient backward curvature coincided with and was evidently caused by enhancement of growth along the concave and inhibition of growth along the convex side of the curve, a pattern opposite to that prevailing in the earlier stages of downward curvature. There were periods during the gravitropic response when the normally unimodal growth-rate distribution within the elongation zone became bimodal with two peaks of rapid elongation separated by a region of reduced elongation rate. This occurred at different times on the convex and concave sides of the graviresponding root. During the period of steady downward curvature the elongation zone along the convex side extended farther toward the tip than in the vertical control. During the period of reduced rate of curvature, the zone of elongation extended farther toward the tip along the concave side of the root. The data show that the gravitropic response pattern varies with time and involves changes in localized elongation rates as well as changes in the length and position of the elongation zone. Models of root gravitropic curvature based on simple unimodal inhibition of growth along the lower side cannot account for these complex growth patterns.

Vegetation root zone storage and rooting depth, derived from local calibration of a global hydrological model

NASA Astrophysics Data System (ADS)

van der Ent, R.; Van Beek, R.; Sutanudjaja, E.; Wang-Erlandsson, L.; Hessels, T.; Bastiaanssen, W.; Bierkens, M. F.

2017-12-01

The storage and dynamics of water in the root zone control many important hydrological processes such as saturation excess overland flow, interflow, recharge, capillary rise, soil evaporation and transpiration. These processes are parameterized in hydrological models or land-surface schemes and the effect on runoff prediction can be large. Root zone parameters in global hydrological models are very uncertain as they cannot be measured directly at the scale on which these models operate. In this paper we calibrate the global hydrological model PCR-GLOBWB using a state-of-the-art ensemble of evaporation fields derived by solving the energy balance for satellite observations. We focus our calibration on the root zone parameters of PCR-GLOBWB and derive spatial patterns of maximum root zone storage. We find these patterns to correspond well with previous research. The parameterization of our model allows for the conversion of maximum root zone storage to root zone depth and we find that these correspond quite well to the point observations where available. We conclude that climate and soil type should be taken into account when regionalizing measured root depth for a certain vegetation type. We equally find that using evaporation rather than discharge better allows for local adjustment of root zone parameters within a basin and thus provides orthogonal data to diagnose and optimize hydrological models and land surface schemes.

Vegetation root zone storage and rooting depth, derived from local calibration of a global hydrological model

NASA Astrophysics Data System (ADS)

van der Ent, Ruud; van Beek, Rens; Sutanudjaja, Edwin; Wang-Erlandsson, Lan; Hessels, Tim; Bastiaanssen, Wim; Bierkens, Marc

2017-04-01

The storage and dynamics of water in the root zone control many important hydrological processes such as saturation excess overland flow, interflow, recharge, capillary rise, soil evaporation and transpiration. These processes are parameterized in hydrological models or land-surface schemes and the effect on runoff prediction can be large. For root zone parameters in global hydrological models are very uncertain as they cannot be measured directly at the scale on which these models operate. In this paper we calibrate the global hydrological model PCR-GLOBWB using a state-of-the-art ensemble of evaporation fields derived by solving the energy balance for satellite observations. We focus our calibration on the root zone parameters of PCR-GLOBWB and derive spatial patterns of maximum root zone storage. We find these patterns to correspond well with previous research. The parameterization of our model allows for the conversion of maximum root zone storage to root zone depth and we find that these correspond quite well to the point observations where available. We conclude that climate and soil type should be taken into account when regionalizing measured root depth for a certain vegetation type. We equally find that using evaporation rather than discharge better allows for local adjustment of root zone parameters within a basin and thus provides orthogonal data to diagnose and optimize hydrological models and land surface schemes.

Consecutive assessment of FA and ADC values of normal lumbar nerve roots from the junction of the dura mater.

PubMed

Miyagi, Ryo; Sakai, Toshinori; Yamabe, Eiko; Yoshioka, Hiroshi

2015-06-27

Diffusion weighted imaging (DWI) and diffusion tensor imaging (DTI) are widely used in the evaluation of the central nervous system and recently have been reported as a potential tool for diagnosis of the peripheral nerve or the lumbar nerve entrapment. The purpose of this study was to evaluate consecutive changes in apparent diffusion coefficient (ADC) and fractional anisotropy (FA) values of normal lumbar nerve roots from the junction of the dura mater. The lumbar spinal nerves were examined in 6 male healthy volunteers (mean age, 35 years) with no experiences of sciatica, with a 3.0-T MR unit using a five-element phased-array surface coil. DTI was performed with the following imaging parameters: 11084.6/73.7 ms for TR/TE; b-value, 800 s/mm2; MPG, 33 directions; slice thickness, 1.5 mm; and total scan time, 7 min 35 s. ADC and FA values at all consecutive points along the L4, L5 and S1 nerves were quantified on every 1.5 mm slice from the junction of the dura mater using short fiber tracking. ADC values of all L4, 5, and S1 nerve roots decreased linearly up to 15 mm from the dura junction and was constant distally afterward. ADC values in the proximal portion demonstrated S1 > L5 > L4 (p < 0.05). On the other hand, FA values increased linearly up to 15 mm from the dura junction, and was constant distally afterward. FA values in the proximal portion showed L4 > L5 > S1 (p < 0.05). Our study demonstrated that ADC and FA values of each L4, 5, and S1 at the proximal portion from the junction of the dura matter changed linearly. It would be useful to know the normal profile of DTI values by location of each nerve root so that we can detect subtle abnormalities in each nerve root.

Prior-knowledge-based spectral mixture analysis for impervious surface mapping

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

Zhang, Jinshui; He, Chunyang; Zhou, Yuyu

2014-01-03

In this study, we developed a prior-knowledge-based spectral mixture analysis (PKSMA) to map impervious surfaces by using endmembers derived separately for high- and low-density urban regions. First, an urban area was categorized into high- and low-density urban areas, using a multi-step classification method. Next, in high-density urban areas that were assumed to have only vegetation and impervious surfaces (ISs), the Vegetation-Impervious model (V-I) was used in a spectral mixture analysis (SMA) with three endmembers: vegetation, high albedo, and low albedo. In low-density urban areas, the Vegetation-Impervious-Soil model (V-I-S) was used in an SMA analysis with four endmembers: high albedo, lowmore » albedo, soil, and vegetation. The fraction of IS with high and low albedo in each pixel was combined to produce the final IS map. The root mean-square error (RMSE) of the IS map produced using PKSMA was about 11.0%, compared to 14.52% using four-endmember SMA. Particularly in high-density urban areas, PKSMA (RMSE = 6.47%) showed better performance than four-endmember (15.91%). The results indicate that PKSMA can improve IS mapping compared to traditional SMA by using appropriately selected endmembers and is particularly strong in high-density urban areas.« less

Vasorelaxant prenylated flavonoids from the roots of Sophora flavescens.

PubMed

Kim, Chul Young; Kim, Hyun Jung; Kim, Kyeong-Man; Oak, Min-Ho

2013-01-01

Bioassay-guided fractionation of the methanol extract from the root of Sophora flavescens led to the isolation of eight known prenylated flavonoids responsible for the vasorelaxation activity in porcine coronary arteries. Among them, kushenol N and 5-methylsophoraflavanone B strongly induced the relaxation of porcine coronary arteries with respective ED(50) values of 8.6 and 12.4 µM. This activity and the results of a high-performance liquid chromatographic analysis suggest that kushenol N and 5-methylsophoraflavanone B could be active markers in the S. flavescens extract for vasorelaxation activity.

Calculus detection technologies: where do we stand now?

PubMed Central

Archana, V

2014-01-01

Epidemiological studies have implicated dental calculus as an ideal substrate for subgingival microbial colonization. Therefore, the main objective of periodontal therapy is to eliminate the microbial biofilm along with the calculus deposits from the root surface by root surface debridement. Over the past years, a large number of clinical and laboratory studies have been conducted to evaluate the efficacy of calculus removal by various methods. None of these conventional methods or devices was effective in completely eliminating all the calculus from the diseased root surfaces. In this context, a number of newer technologies have been developed to identify and selectively remove the dental calculus. Regarding this fact, the present article highlights a critical review of these devices based on published clinical and experimental data. PMID:25870667

Calculus detection technologies: where do we stand now?

PubMed

Archana, V

2014-01-01

Epidemiological studies have implicated dental calculus as an ideal substrate for subgingival microbial colonization. Therefore, the main objective of periodontal therapy is to eliminate the microbial biofilm along with the calculus deposits from the root surface by root surface debridement. Over the past years, a large number of clinical and laboratory studies have been conducted to evaluate the efficacy of calculus removal by various methods. None of these conventional methods or devices was effective in completely eliminating all the calculus from the diseased root surfaces. In this context, a number of newer technologies have been developed to identify and selectively remove the dental calculus. Regarding this fact, the present article highlights a critical review of these devices based on published clinical and experimental data.