A new method for rapid screening of xenobiotic phloem mobility in plants

2000 ◽  
Vol 27 (9) ◽  
pp. 835
Author(s):  
Ning Wang ◽  
Sze-Mei Cindy Lau ◽  
Gregory Rogers ◽  
Thomas Ray
Keyword(s):  
Chemical Properties ◽  
New Method ◽  
Rapid Screening ◽  
Assimilate Transport ◽  
Phloem Sap ◽  
Hydrophobic Polymers ◽  
Intact Plants ◽  
Solute Movement ◽  
Phloem Mobility ◽  
Aphid Stylectomy

This paper originates from a presentation at the International Conference on Assimilate Transport and Partitioning, Newcastle, NSW, August 1999 The deposition of hydrophobic polymers in the xylem of wheat grain floral axes prevents water and solute movement into grains via the xylem (xylem discontinuity). The only pathway for translocation of photosynthate or externally applied xenobiotics into wheat grains is via the phloem. We have developed a new method based on the xylem discontinuity for rapidly screening phloem mobility of xenobiotics. By quantifying xenobiotic concentration in grains and excised plants after the compounds were applied through the cut stems, the phloem mobility can be estimated quantitatively. The phloem mobility obtained with our new grain-based method was correlated to xenobiotic chemical properties such as log Kow, pKa and electrical charge, and is consistent with published literature. Phloem mobility values determined by the grain-based assay were correlated to those from the direct phloem sap (aphid stylet exudate) assay of excised and intact plants, indicating that the grain-based assay is as reliable as the direct assay with aphid stylectomy. The new grain-based method is simple, quick, and can be scaled up for rapid screening of xenobiotic phloem mobility in plants. Similar seed (fruit)-based assay could also be developed with wide ranges of plant species that use the phloem as the only pathway for supplying water and nutrients into their seeds or fruits.

A New Method of Producing Carbon Anode by High-Temperature Mould Pressing

2011 ◽  
Vol 415-417 ◽  
pp. 611-616
Author(s):  
Yao Wu Wang ◽  
Nai Xiang Feng ◽  
Jing You
Keyword(s):  
High Temperature ◽  
Bulk Density ◽  
Electrical Resistance ◽  
Chemical Properties ◽  
New Method ◽  
Carbon Anode ◽  
Crushing Strength ◽  
Industrial Carbon ◽  
Physico Chemical ◽  
Carbon Anodes

Laboratory-scale carbon anodes were produced by a new method of high-temperature mould pressing, and their physico-chemical properties were studied in laboratory. The results showed that the bulk density of carbon anodes produced by high-temperature mould pressing are 1.61-1.63g/cm3, they are higher than industrial carbon anode by 0.06 g/cm3, but the specific electrical resistance is higher and crushing strength is lower.

scholarly journals A New Method for Rapid Screening of End-Point PCR Products: Application to Single Genome Amplified HIV and SIV Envelope Amplicons

PLoS ONE ◽  
2015 ◽  
Vol 10 (6) ◽  
pp. e0128188 ◽  
Author(s):  
Laurent Houzet ◽  
Claire Deleage ◽  
Anne-Pascale Satie ◽  
Laetitia Merlande ◽  
Dominique Mahe ◽  
...  
Keyword(s):  
New Method ◽  
Rapid Screening ◽  
End Point ◽  
Single Genome ◽  
Pcr Products

scholarly journals A New Method to Find the Wiener Index of Hypergraphs

2020 ◽  
Vol 2020 ◽  
pp. 1-6
Author(s):  
Yalan Li ◽  
Bo Deng
Keyword(s):  
Organic Compounds ◽  
Chemical Properties ◽  
Wiener Index ◽  
New Method ◽  
Physical And Chemical Properties ◽  
Mathematical Chemistry ◽  
Physical And Chemical ◽  
And Chemical Properties

The Wiener index is defined as the summation of distances between all pairs of vertices in a graph or in a hypergraph. Both models—graph-theoretical and hypergraph-theoretical—are used in mathematical chemistry for quantitatively studying physical and chemical properties of classical and nonclassical organic compounds. In this paper, we consider relationships between hypertrees and trees and hypercycles and cycles with respect to their Wiener indices.

Uptake, partitioning and utilization of carbon and nitrogen in the phloem bleeding tree, Tasmanian blue gum (Eucalyptus globulus)

2000 ◽  
Vol 27 (9) ◽  
pp. 869
Author(s):  
John S. Pate ◽  
David J. Arthur
Keyword(s):  
Eucalyptus Globulus ◽  
Assimilate Transport ◽  
Concentration Gradients ◽  
Phloem Sap ◽  
Empirical Modelling ◽  
Carbon And Nitrogen ◽  
C And N ◽  
Four Levels ◽  
Gains And Losses ◽  
Growing Shoot

This paper originates from a presentation at the International Conference on Assimilate Transport and Partitioning, Newcastle, NSW, August 1999 An empirical modelling procedure was employed to follow uptake, transport and utilization of photo-assimilated carbon (C) and soil-derived nitrogen (N) over a 19-d period (November 1998) in 2-year-old plantation-grown trees of Eucalyptus globulus Labill. Models utilized data for gains and losses of C and N in dry matter (DM) of tree parts, CO2 exchanges and transpiration of foliage, respiratory losses of stems and roots, C:N weight ratios of xylem and phloem sap collected at different sites within the system, and phloem sap sugar concentration gradients along trunks and branches to indicate directions of assimilate flow. The model for C depicted the fate of exported fixed C from four levels of branches on the shoot system, cycling of 16% of the C supplied from shoot to root back to the shoot in xylem, major involvement of xylem-derived C in nourishment of rapidly growing branches, and a net daily respiratory output per tree equivalent to 39% of its net daytime photosynthetic gain in C by foliage. The model for N showed that upper growing shoot parts gained more N mobilized from lower branches than was being acquired from soil. It also indicated high rates of cycling of N through mature foliage, effective retention of xylem-derived N by growing branches and apices, and feedback of substantial amounts of phloem-exported N from lower branches into xylem moving further up the trunk. Transpiration loss per tree was equivalent to 272 mL g–1 DM accumulated. Data are discussed in relation to similarly executed C:N partitioning studies on herbaceous annual species.

A rapid screening method for Rhizobium meliloti symbiotic nitrogenase activity

1982 ◽  
Vol 28 (2) ◽  
pp. 265-268 ◽  
Author(s):  
J. C. Sirois ◽  
E. A. Peterson
Keyword(s):  
Positive Relationship ◽  
Rhizobium Meliloti ◽  
Nitrogenase Activity ◽  
Screening Method ◽  
Dry Weight ◽  
Rapid Screening ◽  
Experimental Conditions ◽  
Intact Plants ◽  
Medicago Sativa L ◽  
Rapid Screening Method

A method for screening Rhizobium meliloti isolates for their symbiotic nitrogenase activity with alfalfa (Medicago sativa L.) cv. Apollo is described. The nitrogenase activity of each isolate is assessed by measuring the reduction of acetylene (C2H2) to ethylene (C2H4) by 50 intact plants grown in 10 plastic pouches for 2 weeks. The method is rapid, sensitive, reproducible, and accurate enough to differentiate 29 Rhizobium isolates and 5 authentic strains into 13 subsets. Under the experimental conditions used, nodulation occurred within 5 days of inoculation and there was a significant positive relationship between the nitrogenase activity of those isolates which reduced more than 60 nmol C2H2∙plant−1∙h−1 and the dry weight of the shoots of the nodulated plants in 2 weeks of growth.

scholarly journals A new method for rapid screening of bacterial species- or subspecies-specific DNA probes

2003 ◽  
Vol 219 (1) ◽  
pp. 121-127 ◽  
Author(s):  
Joong-Ki Kook ◽  
Mi-Kwang Kim ◽  
Jin-Hyo Seong ◽  
Dong-Kie Kim ◽  
Byung-Ock Kim ◽  
...  
Keyword(s):  
Bacterial Species ◽  
Dna Probes ◽  
New Method ◽  
Rapid Screening

Dynamic transitions in the translocated phloem filament protein

2000 ◽  
Vol 27 (9) ◽  
pp. 733 ◽  
Author(s):  
Kirsten Leineweber ◽  
Alexander Schulz ◽  
Gary A. Thompson
Keyword(s):  
Disulfide Bonds ◽  
Assimilate Transport ◽  
Phloem Sap ◽  
Folding Intermediates ◽  
P Protein ◽  
Molecular Masses ◽  
P Proteins ◽  
The Stability ◽  
Filament Protein ◽  
Higher Sensitivity

This paper originates from a presentation at the International Conference on Assimilate Transport and Partitioning, Newcastle, NSW, August 1999 Recent evidence suggests that the P-proteins of Cucurbita maxima exist in at least two structural states: large polymers that are immobilized in individual sieve elements and small polymers or individual subunits that are translocated over long distances. We investigated variation in the structure of the phloem filament protein (phloem protein 1 or PP1) to determine the translocated form of the protein and its relationship to the polymerized state. It was demonstrated that the stability, folding state and assembly of the phloem filament protein rely on distinct intramolecular disulfide bonds. Acid trapping experiments combined with intergeneric grafts revealed that the phloem filament protein is translocated as an 88 kDa globular protein. By altering the pH of the collection buffer (pH 2–10), four individual conformational isoforms of PP1 with molecular masses of 81, 83, 85 and 88 kDa were consistently observed. The 81 kDa isoform represents the totally reduced phloem filament protein, the 83 and 85 kDa isoforms folding intermediates, and the 88 kDa its native soluble translocated form. The 83 and 85 kDa folding intermediates are susceptible to aggregation causing the gelation and formation of P-protein filaments in oxidized phloem sap. In contrast to the 88 kDa globular transport form, the 81, 83 and 85 kDa isoforms possibly exhibit lower stability, and therefore a higher sensitivity to proteolytic digestion.

Analysis of Triazole-Based Metabolites in Plant Materials Using Differential Mobility Spectrometry to Improve LC/MS/MS Selectivity

2012 ◽  
Vol 95 (6) ◽  
pp. 1768-1776 ◽  
Author(s):  
Julia Jasak ◽  
Yves Le Blanc ◽  
Karl Speer ◽  
Patrick Billian ◽  
Ralf M Schoening
Keyword(s):  
Chemical Properties ◽  
Residue Level ◽  
Differential Mobility Spectrometry ◽  
New Method ◽  
Differential Mobility ◽  
Triazole Derivative ◽  
Plant Materials ◽  
Physical Chemical

Abstract Triazole-derivative metabolites can occur in plant and animal materials and in water. Due to their physical-chemical properties, their analysis in complex matrixes is very difficult. The objective of this work was to develop a method for the analysis of these analytes that is easy to handle, quick, and enables quantification at a residue level of 0.01 mg/kg. Using the LC-differential mobility spectrometry/MS/MS system, cleanup and derivatization processes became unnecessary. For more than 10 representative plant materials it could be shown that the new method is valid and reproducible, thus leading to accurate and reliable results.

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