scholarly journals Comparison of 2,4-Dichlorophenoxyacetic Acid Degradation and Plasmid Transfer in Soil Resulting from Bioaugmentation with Two Different pJP4 Donors

2000 ◽  
Vol 66 (8) ◽  
pp. 3399-3407 ◽  
Author(s):  
D. T. Newby ◽  
T. J. Gentry ◽  
I. L. Pepper
Keyword(s):  
Ralstonia Eutropha ◽  
Plasmid Transfer ◽  
Indigenous Populations ◽  
Dichlorophenoxyacetic Acid ◽  
Soil System ◽  
E Coli ◽  
Indigenous Plasmid ◽  
Key Factor ◽  
2,4 Dichlorophenoxyacetic Acid ◽  
The Impact

ABSTRACT A pilot field study was conducted to assess the impact of bioaugmentation with two plasmid pJP4-bearing microorganisms: the natural host, Ralstonia eutropha JMP134, and a laboratory-generated strain amenable to donor counterselection,Escherichia coli D11. The R. eutropha strain contained chromosomal genes necessary for mineralization of 2,4-dichlorophenoxyacetic acid (2,4-D), while the E. colistrain did not. The soil system was contaminated with 2,4-D alone or was cocontaminated with 2,4-D and Cd. Plasmid transfer to indigenous populations, plasmid persistence in soil, and degradation of 2,4-D were monitored over a 63-day period in the bioreactors. To assess the impact of contaminant reexposure, aliquots of bioreactor soil were reamended with additional 2,4-D. Both introduced donors remained culturable and transferred plasmid pJP4 to indigenous recipients, although to different extents. Isolated transconjugants were members of theBurkholderia and Ralstonia genera, suggesting multiple, if not successive, plasmid transfers. Upon a second exposure to 2,4-D, enhanced degradation was observed for all treatments, suggesting microbial adaptation to 2,4-D. Upon reexposure, degradation was most rapid for the E. coli D11-inoculated treatments. Cd did not significantly impact 2,4-D degradation or transconjugant formation. This study demonstrated that the choice of donor microorganism might be a key factor to consider for bioaugmentation efforts. In addition, the establishment of an array of stable indigenous plasmid hosts at sites with potential for reexposure or long-term contamination may be particularly useful.

scholarly journals Detection and Characterization of Plasmid pJP4 Transfer to Indigenous Soil Bacteria

2000 ◽  
Vol 66 (1) ◽  
pp. 290-296 ◽  
Author(s):  
D. T. Newby ◽  
K. L. Josephson ◽  
I. L. Pepper
Keyword(s):  
Gene Transfer ◽  
Ralstonia Eutropha ◽  
Indigenous Populations ◽  
Mercury Resistance ◽  
Pcr Analysis ◽  
Dichlorophenoxyacetic Acid ◽  
Molecular Fingerprints ◽  
Dry Soil ◽  
Biolog Analysis ◽  
2,4 Dichlorophenoxyacetic Acid

ABSTRACT Prior to gene transfer experiments performed with nonsterile soil, plasmid pJP4 was introduced into a donor microorganism,Escherichia coli ATCC 15224, by plate mating withRalstonia eutropha JMP134. Genes on this plasmid encode mercury resistance and partial 2,4-dichlorophenoxyacetic acid (2,4-D) degradation. The E. coli donor lacks the chromosomal genes necessary for mineralization of 2,4-D, and this fact allows presumptive transconjugants obtained in gene transfer studies to be selected by plating on media containing 2,4-D as the carbon source. Use of this donor counterselection approach enabled detection of plasmid pJP4 transfer to indigenous populations in soils and under conditions where it had previously not been detected. In Madera Canyon soil, the sizes of the populations of presumptive indigenous transconjugants were 107 and 108 transconjugants g of dry soil−1 for samples supplemented with 500 and 1,000 μg of 2,4-D g of dry soil−1, respectively. Enterobacterial repetitive intergenic consensus PCR analysis of transconjugants resulted in diverse molecular fingerprints. Biolog analysis showed that all of the transconjugants were members of the genusBurkholderia or the genus Pseudomonas. No mercury-resistant, 2,4-D-degrading microorganisms containing large plasmids or the tfdB gene were found in 2,4-D-amended uninoculated control microcosms. Thus, all of the 2,4-D-degrading isolates that contained a plasmid whose size was similar to the size of pJP4, contained the tfdB gene, and exhibited mercury resistance were considered transconjugants. In addition, slightly enhanced rates of 2,4-D degradation were observed at distinct times in soil that supported transconjugant populations compared to controls in which no gene transfer was detected.

scholarly journals Impact of Ionic Liquids on Induction of Wheat Microspore Embryogenesis and Plant Regeneration

Agronomy ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 839
Author(s):  
Dorota Weigt ◽  
Idzi Siatkowski ◽  
Magdalena Magaj ◽  
Agnieszka Tomkowiak ◽  
Jerzy Nawracała
Keyword(s):  
Ionic Liquids ◽  
Plant Regeneration ◽  
Positive Impact ◽  
Microspore Embryogenesis ◽  
Green Plant ◽  
Induction Medium ◽  
Dichlorophenoxyacetic Acid ◽  
2,4 Dichlorophenoxyacetic Acid ◽  
The Impact

Ionic liquids are novel compounds with unique chemical and physical properties. They can be received based on synthetic auxins like 2,4-dichlorophenoxyacetic acid or dicamba, which are commonly used hormones in microspore embryogenesis. Nevertheless, ionic liquids have not been adapted in plant in vitro culture thus far. Therefore, we studied the impact of ionic liquids on the ability to undergo microspore embryogenesis in anther cultures of wheat. Two embryogenic and two recalcitrant genotypes were used for this study. Ten combinations of ionic liquids and 2,4-dichlorophenoxyacetic acid were added to the induction medium. In most cases, they stimulated induction of microspore embryogenesis and green plant regeneration more than a control medium supplemented with only 2,4-dichlorophenoxyacetic acid. Two treatments were the most favorable, resulting in over two times greater efficiency of microspore embryogenesis induction in comparison to the control. The effect of breaking down the genotype recalcitrance (manifested by green plant formation) was observed under the influence of 5 ionic liquids treatments. Summing up, ionic liquids had a positive impact on microspore embryogenesis induction and green plant regeneration, increasing the efficiency of these phenomena in both embryogenic and recalcitrant genotypes. Herbicidal ionic liquids can be successfully used in in vitro cultures.

scholarly journals Auxins Regulations of Branched Spike Development and Expression of TFL, a LEAFY-Like Gene in Branched Spike Wheat (Triticum aestivum)

2017 ◽  
Vol 9 (2) ◽  
pp. 27
Author(s):  
Wang Yue ◽  
Sun Fulai ◽  
Gao Qingrong ◽  
Zhang Yanxia ◽  
Wang Nan ◽  
...  
Keyword(s):  
Photosynthetic Pigment ◽  
Dry Mass ◽  
Dichlorophenoxyacetic Acid ◽  
Naphthaleneacetic Acid ◽  
Branched Spike ◽  
Spike Development ◽  
2,4 Dichlorophenoxyacetic Acid ◽  
The Impact ◽  
Indole 3 Acetic Acid ◽  
Putative Homologue

Branched spike wheat is a hexaploid germplasm with branched rachis on its main rachises, and the crucial period for branched rachises occurrence and development is just after the two ridges stage of shoot apex. Natural [indole-3-acetic acid (IAA), indole-3butyric acid (IBA)] and synthetic [(1-naphthaleneacetic acid (NAA), 2,4-Dichlorophenoxyacetic acid (2,4-D)] auxins were applied at this period to investigate the spike traits, seedling growth and photosynthesis related characters and expression of a putative homologue of the LEAFY in branched spike wheat. The four types of experienced auxins induced similar effects on these foresaid characters, although the impact extents were different among the auxins treatments. More branched rachis, spikelets, fertile florets and longer branched rachis were obtained in plants with IAA and IBA at 0.1 mM or NAA and 2,4-D at 1.0mM than those plants with no auxin treated. Auxin treatments also increased fresh and dry mass, photosynthetic pigment and parameters. TFL, a LEAFY-like gene was cloned in branched spike wheat and TFL mRNA expression was quantified using real-time reverse transcriptase-PCR. Application of the auxins accelerated the rise in TFL expression during the periods of branched rachises occurrence and extension. The data supports the hypothesis that auxins play a central role in the regulation branched spike development and TFL might correlate with the development of branched rachises in branched spike wheat.

scholarly journals Impact of Ralstonia eutropha's Poly(3-Hydroxybutyrate) (PHB) Depolymerases and Phasins on PHB Storage in Recombinant Escherichia coli

2014 ◽  
Vol 80 (24) ◽  
pp. 7702-7709 ◽  
Author(s):  
Jessica Eggers ◽  
Alexander Steinbüchel
Keyword(s):  
Escherichia Coli ◽  
Ralstonia Eutropha ◽  
Model Organism ◽  
Dry Weight ◽  
Growth Behavior ◽  
Carbon Limitation ◽  
Content Type ◽  
Phb Depolymerase ◽  
E Coli ◽  
The Impact

ABSTRACTThe model organism for polyhydroxybutyrate (PHB) biosynthesis,Ralstonia eutrophaH16, possesses multiple isoenzymes of granules coating phasins as well as of PHB depolymerases, which degrade accumulated PHB under conditions of carbon limitation. In this study, recombinantEscherichia coliBL21(DE3) strains were used to study the impact of selected PHB depolymerases ofR. eutrophaH16 on the growth behavior and on the amount of accumulated PHB in the absence or presence of phasins. For this purpose, 20 recombinantE. coliBL21(DE3) strains were constructed, which harbored a plasmid carrying thephaCABoperon fromR. eutrophaH16 to ensure PHB synthesis and a second plasmid carrying different combinations of the genes encoding a phasin and a PHB depolymerase fromR. eutrophaH16. It is shown in this study that the growth behavior of the respective recombinantE. colistrains was barely affected by the overexpression of the phasin and PHB depolymerase genes. However, the impact on the PHB contents was significantly greater. The strains expressing the genes of the PHB depolymerases PhaZ1, PhaZ2, PhaZ3, and PhaZ7 showed 35% to 94% lower PHB contents after 30 h of cultivation than the control strain. The strain harboringphaZ7reached by far the lowest content of accumulated PHB (only 2.0% [wt/wt] PHB of cell dry weight). Furthermore, coexpression of phasins in addition to the PHB depolymerases influenced the amount of PHB stored in cells of the respective strains. It was shown that the phasins PhaP1, PhaP2, and PhaP4 are not substitutable without an impact on the amount of stored PHB. In particular, the phasins PhaP2 and PhaP4 seemed to limit the degradation of PHB by the PHB depolymerases PhaZ2, PhaZ3, and PhaZ7, whereas almost no influence of the different phasins was observed ifphaZ1was coexpressed. This study represents an extensive analysis of the impact of PHB depolymerases and phasins on PHB accumulation and provides a deeper insight into the complex interplay of these enzymes.

Dynamique de la végétation d'emprises de lignes de transport d'énergie

1984 ◽  
Vol 62 (8) ◽  
pp. 1730-1738
Author(s):  
M. Darveau ◽  
P. Bellefleur
Keyword(s):  
Woody Species ◽  
Power Line ◽  
Power Lines ◽  
Underlying Structure ◽  
Dichlorophenoxyacetic Acid ◽  
Border Line ◽  
Control Power ◽  
Composition And Structure ◽  
2,4 Dichlorophenoxyacetic Acid ◽  
The Impact

We made a preliminary study of the impact of phytocides on plant dynamics in the corridors of Hydro-Québec power lines. Three hypotheses were tested: the first assumed that the phytocides changed vegetation composition and structure in the corridors; the second assumed that the corridor under the power line favored the development of an ecotone at its border with the forest; the third assumed that the method used for initial cutting of the corridors (bulldozer or chain saw) affected the forthcoming vegetation for over 15 years. Vegetation was sampled on one control power line and four power lines maintained with mixtures of picloram, 2,4-dichlorophenoxyacetic acid, 2,4,5-trichlorophenoxyacetic acid, and sodium trichloroacetate. Multidimensional statistical analysis was used to show the underlying structure of the raw data and to test the hypotheses. We found out that phytocides are very efficient on woody species to the advantage of herbs, mostly grass, which invaded the corridors and created rather stable artificial communities. No significant ecotone was found at the border line of the corridors and the forest. The influence of the method for initial cutting of the corridors, although severe the first few years, disappeared after about 10 years under the action of the phytocides.

scholarly journals Differential regulation of GS-GOGAT gene expression by plant growth regulators in Arabidopsis seedlings

2016 ◽  
Vol 68 (2) ◽  
pp. 399-404 ◽  
Author(s):  
Milan Dragicevic ◽  
Ana Simonovic ◽  
Milica Bogdanovic ◽  
Angelina Subotic ◽  
Nabil Ghalawenji ◽  
...  
Keyword(s):  
Plant Growth ◽  
Plant Growth Regulators ◽  
Growth Regulators ◽  
Expression Patterns ◽  
Nuclear Gene ◽  
Glutamate Synthase ◽  
Ammonium Assimilation ◽  
Dichlorophenoxyacetic Acid ◽  
2,4 Dichlorophenoxyacetic Acid ◽  
The Impact

Primary and secondary ammonium assimilation is catalyzed by the glutamine synthetase-glutamate synthase (GS-GOGAT) pathway in plants. The Arabidopsis genome contains five cytosolic GS1 genes (GLN1;1 - GLN1;5), one nuclear gene for chloroplastic GS2 isoform (GLN2), two Fd-GOGAT genes (GLU1 and GLU2) and a GLT1 gene coding for NADH-GOGAT. Even though the regulation of GS and GOGAT isoforms has been extensively studied in response to various environmental and metabolic cues in many plant species, little is known about the effects of phytohormones on their regulation. The objective of this study was to investigate the impact of representative plant growth regulators, kinetin (KIN), abscisic acid (ABA), gibberellic acid (GA3) and 2,4-dichlorophenoxyacetic acid (2,4-D), on the expression of A. thaliana GS and GOGAT genes. The obtained results indicate that GS and GOGAT genes are differentially regulated by growth regulators in shoots and roots. KIN and 2,4-D repressed GS and GOGAT expression in roots, with little effect on transcript levels in shoots. KIN affected all tested genes; 2,4-D was apparently more selective and less potent. ABA induced the expression of GLN1;1 and GLU2 in whole seedlings, while GA3 enhanced the expression of all tested genes in shoots, except GLU2. The observed expression patterns are discussed in relation to physiological roles of investigated plant growth regulators and N-assimilating enzymes.

scholarly journals Phytotoxicity in Seedlings of Rhizophora mangle (L.) Exposed to 2,4-Dichlorophenoxyacetic Acid under Experimental Conditions

2021 ◽  
Vol 9 (12) ◽  
pp. 1417
Author(s):  
Carlos A. Chan-Keb ◽  
Claudia M. Agraz-Hernández ◽  
Román A. Pérez-Balan ◽  
Eduardo J. Gutiérrez-Alcántara ◽  
Raquel Muñiz-Salazar ◽  
...  
Keyword(s):  
Chlorophyll A ◽  
Biomass Production ◽  
Agricultural Practices ◽  
Rhizophora Mangle ◽  
Dichlorophenoxyacetic Acid ◽  
Inhibitory Effects ◽  
Experimental Conditions ◽  
Environmental Goods ◽  
2,4 Dichlorophenoxyacetic Acid ◽  
The Impact

Mangroves are considered one of the most productive ecosystems worldwide, providing multiple environmental goods and services; however, in recent years, there have been modifications and deterioration in the structure and function of these ecosystems, caused by various natural events and anthropic activities, such as the construction of roads, wastewater discharge, unsustainable livestock, and agricultural practices, as well as the impact of chemicals, such as heavy metals, oil spills, and the use of herbicides. In this research, phytotoxic effects on seedlings of Rhizophora mangle were evaluated at an exposure of five dilutions w/v (5%, 10%, 25%, 50%, and 100%) of the commercial presentation of 2,4-dichlorophenoxyacetic acid (2,4-D). Propagules grown in a greenhouse under local tidal regimes were used, so the growth of stem diameter, height, biomass production in root, leaves, and stems, as well as the concentration of chlorophyll a of the exposed seedlings were measured. The comparison of these parameters in seedlings with only seawater presented significant differences (p ≤ 0.05) and inhibitory effects on growth (diameter), the stem concentration of chlorophyll a, and the production of biomass of leaves, stems, and roots. The inhibitory effect of exposure to 2,4-D on chlorophyll production and root biomass is highlighted, with an average decrease of 45% relative to the control. The sensitivity of the Rhizophora mangle seedlings to the applied concentrations of herbicide evidence the inhibitory effects on the morphological variables of biomass production and chlorophyll a production in mangrove leaves.

scholarly journals Characterization of a Second tfd Gene Cluster for Chlorophenol and Chlorocatechol Metabolism on Plasmid pJP4 in Ralstonia eutropha JMP134(pJP4)

2000 ◽  
Vol 182 (15) ◽  
pp. 4165-4172 ◽  
Author(s):  
Caroline M. Laemmli ◽  
Johan H. J. Leveau ◽  
Alexander J. B. Zehnder ◽  
Jan Roelof van der Meer
Keyword(s):  
Ralstonia Eutropha ◽  
Open Reading Frames ◽  
Dichlorophenoxyacetic Acid ◽  
Dot Blot ◽  
Catabolic Plasmid ◽  
Pathway Expression ◽  
Dienelactone Hydrolase ◽  
2,4 Dichlorophenoxyacetic Acid ◽  
Extension Analysis

ABSTRACT Within the 5.9-kb DNA region between the tfdR andtfdK genes on the 2,4-dichlorophenoxyacetic acid (2,4-D) catabolic plasmid pJP4 from Ralstonia eutropha JMP134, we identified five open reading frames (ORFs) with significant homology to the genes for chlorocatechol and chlorophenol metabolism (tfdCDEF and tfdB) already present elsewhere on pJP4. The five ORFs were organized and assigned as follows:tfdD II C II E II F IIand tfdB II (in short, thetfd II cluster), by analogy totfdCDEF and tfdB (thetfd I cluster). Primer extension analysis of mRNA isolated from 2,4-D-grown R. eutropha JMP134 identified a single transcription start site in front of the first gene of the cluster, tfdD II, suggesting an operon-like organization for the tfd II genes. By expressing each ORF in Escherichia coli, we confirmed that tfdD II coded for a chloromuconate cycloisomerase, tfdC II coded for a chlorocatechol 1,2-dioxygenase, tfdE II coded for a dienelactone hydrolase, tfdF II coded for a maleylacetate reductase, and tfdB II coded for a chlorophenol hydroxylase. Dot blot hybridizations of mRNA isolated from R. eutropha JMP134 showed that bothtfd I and tfd II genes are transcribed upon induction with 2,4-D. Thus, the functions encoded by the tfd II genes seem to be redundant with respect to those of the tfd I cluster. One reason why the tfd II genes do not disappear from plasmid pJP4 might be the necessity for keeping the regulatory genes for the 2,4-D pathway expression tfdR andtfdS.

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