Genome plasticity during the acquisition of embryogenic competence

Genome ◽  
1999 ◽  
Vol 42 (6) ◽  
pp. 1134-1143 ◽  
Author(s):  
Chiara Geri ◽  
Alessandra Turrini ◽  
Lucia Giorgetti ◽  
Elisa Nicoletti ◽  
Vittoria Nuti Ronchi
Keyword(s):  
Nuclear Dna ◽  
Cultured Cells ◽  
Morphological Changes ◽  
Dichlorophenoxyacetic Acid ◽  
Embryogenic Competence ◽  
Daucus Carota L ◽  
Gene Copies ◽  
Slot Blot Analysis ◽  
2,4 Dichlorophenoxyacetic Acid

Hypocotyl explants from carrot and other species experience concomitant segregation events and differentiation of homeotic structures during the first 20 days of culture on 2,4-dichlorophenoxyacetic acid (2,4-D). In addition to these cyto-morphological changes, significant amounts of nuclear DNA are lost, the molecular details of which we investigate in this paper. We have developed a slot-blot analysis assay to study the DNA content of a series of carrot samples; besides the leaves, this survey ranged over different culture timepoints: hypocotyls, cell lines, and somatic embryo stages. We carried on to study the relationship between this DNA loss and sequence complexity modulation. Results from probing sequences that correspond to different degrees of complexity, such as medium repetitive and unique sequences as well as sequences belonging to both classes (ribosomal cistrons, ubiquitin, actin, and chalcone synthase), consistently manifested a reduction in DNA levels during the acquisition of embryogenic competence. In some cases, the cultured cells would contain only 10% of the gene copies observed in the reference tissues. Modulation trends also showed that DNA levels of most sequences recover at the torpedo-plantlet stage, which again correlates DNA modulation and the acquisition of embryogenic competence. These results suggest that similar DNA variations may occur in plants in vivo during meiosis, possibly so that meiotic division may be properly completed.Key words: Daucus carota L., DNA reduction, somatic embryogenesis, totipotency, commitment.

scholarly journals Improving Surface Imprinting Effect by Reducing Nonspecific Adsorption on Non-imprinted Polymer Films for 2,4-D Herbicide Sensors

Chemosensors ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 43
Author(s):  
Jin Chul Yang ◽  
Suck Won Hong ◽  
Jinyoung Park
Keyword(s):  
Morphological Changes ◽  
Unit Weight ◽  
Dichlorophenoxyacetic Acid ◽  
Surface Imprinting ◽  
Imprinted Polymer ◽  
Nonspecific Adsorption ◽  
Chemical Surface ◽  
Silane Modification ◽  
Silanized Silica ◽  
2,4 Dichlorophenoxyacetic Acid

Surface imprinting used for template recognition in nanocavities can be controlled and improved by surface morphological changes. Generally, the lithographic technique is used for surface patterning concerning sensing signal amplification in molecularly imprinted polymer (MIP) thin films. In this paper, we describe the effects of silanized silica molds on sensing the properties of MIP films. Porous imprinted poly(MAA–co–EGDMA) films were lithographically fabricated using silanized or non-treated normal silica replica molds to detect 2,4-dichlorophenoxyacetic acid (2,4-D) herbicide as the standard template. The silanized mold MIP film (st-MIP) (Δf = −1021 Hz) exhibited a better sensing response than the non-treated normal MIP (n-MIP) (Δf = −978 Hz) because the imprinting effects, which occurred via functional groups on the silica surface, could be reduced through silane modification. Particularly, two non-imprinted (NIP) films (st-NIP and n-NIP) exhibited significantly different sensing responses. The st-NIP (Δfst-NIP = −332 Hz) films exhibited lower Δf values than the n-NIP film (Δfn-NIP = −610 Hz) owing to the remarkably reduced functionality against nonspecific adsorption. This phenomenon led to different imprinting factor (IF) values for the two MIP films (IFst-MIP = 3.38 and IFn-MIP = 1.86), which was calculated from the adsorbed 2,4-D mass per poly(MAA–co–EGDMA) unit weight (i.e., QMIP/QNIP). Moreover, it was found that the st-MIP film had better selectivity than the n-MIP film based on the sensing response of analogous herbicide solutions. As a result, it was revealed that the patterned molds’ chemical surface modification, which controls the surface functionality of imprinted films during photopolymerization, plays a role in fabricating enhanced sensing properties in patterned MIP films.

Phytotropins. IV. Effect of Phytotropins on Cultured Plant Cells and Protoplasts

1982 ◽  
Vol 9 (3) ◽  
pp. 297 ◽  
Author(s):  
PJ Larkin ◽  
W Scowcroft ◽  
AE Geissler ◽  
GF Katekar
Keyword(s):  
Petunia Hybrida ◽  
Cultured Cells ◽  
Plant Cells ◽  
Dichlorophenoxyacetic Acid ◽  
Polar Transport ◽  
Suspension Cultured Cells ◽  
Specific Receptors ◽  
Nicotiana Debneyi ◽  
2,4 Dichlorophenoxyacetic Acid

The phytotropins l-(2'-carboxyphenyl)-3-phenylpropane-1,3-dione (CPP) and 5-(2-carboxyphenyl)- 3-phenylpyrazole (CPD) reduced the net efflux of radiolabel from suspension-cultured cells treated with [14C]2,4-dichlorophenoxyacetic acid when present at concentrations comparable to those that inhibit polar transport of auxins in bean petioles. These phytotropins stimulated division of protoplasts of both Nicotiana debneyi and Petunia hybrida at concentrations of exogenous auxins that were otherwise suboptimal for divisions. The results are consistent with the proposal that phytotropins interact with specific receptors to reduce auxin efflux, resulting in increased intracellular auxin concentrations.

scholarly journals Modeling of Phenoxy Acid Herbicide Mineralization and Growth of Microbial Degraders in 15 Soils Monitored by Quantitative Real-Time PCR of the FunctionaltfdAGene

2012 ◽  
Vol 78 (15) ◽  
pp. 5305-5312 ◽  
Author(s):  
Jacob Bælum ◽  
Emmanuel Prestat ◽  
Maude M. David ◽  
Bjarne W. Strobel ◽  
Carsten S. Jacobsen
Keyword(s):  
Real Time ◽  
Real Time Pcr ◽  
Kinetic Models ◽  
Exponential Model ◽  
Dichlorophenoxyacetic Acid ◽  
Order Kinetic ◽  
Clear Trend ◽  
Gene Copies ◽  
2,4 Dichlorophenoxyacetic Acid ◽  
Kinetics Of

ABSTRACTMineralization potentials, rates, and kinetics of the three phenoxy acid (PA) herbicides, 2,4-dichlorophenoxyacetic acid (2,4-D), 4-chloro-2-methylphenoxyacetic acid (MCPA), and 2-(4-chloro-2-methylphenoxy)propanoic acid (MCPP), were investigated and compared in 15 soils collected from five continents. The mineralization patterns were fitted by zero/linear or exponential growth forms of the three-half-order models and by logarithmic (log), first-order, or zero-order kinetic models. Prior and subsequent to the mineralization event,tfdAgenes were quantified using real-time PCR to estimate the genetic potential for degrading PA in the soils. In 25 of the 45 mineralization scenarios, ∼60% mineralization was observed within 118 days. Elevated concentrations oftfdAin the range 1 × 105to 5 × 107gene copies g−1of soil were observed in soils where mineralization could be described by using growth-linked kinetic models. A clear trend was observed that the mineralization rates of the three PAs occurred in the order 2,4-D > MCPA > MCPP, and a correlation was observed between rapid mineralization and soils exposed to PA previously. Finally, for 2,4-D mineralization, all seven mineralization patterns which were best fitted by the exponential model yielded a highertfdAgene potential after mineralization had occurred than the three mineralization patterns best fitted by the Lin model.

Characterization and Properties of Different Glucosyltransferases Isolated from Suspension-Cultured Cells of Daucus carota

1986 ◽  
Vol 41 (4) ◽  
pp. 409-420 ◽  
Author(s):  
Edgar Ingold ◽  
Hanns Ulrich Seitz
Keyword(s):  
Daucus Carota ◽  
Cultured Cells ◽  
Test System ◽  
Enzymatic Activities ◽  
Daucus Carota L ◽  
Low Concentrations ◽  
Nucleotide Sugars ◽  
Glucan Chain ◽  
Glucan Synthesis

Particulate enzymes (14,000 g pellet) from suspension-cultured carrot cells (Daucus carota L.) incorporated glucose from UDP-glucose and GDP-glucose into ethanol-insoluble products which were characterized as glucans or glucoprotein. Based on the test system to assay glucansynthe- tases I and II four different enzymatic activities could be distinguished on the basis of their substrate and divalent cation requirements, the influence of active substances such as nucleotides, nucleotide sugars, cellobiose, and in vivo inhibitors of cell wall glucan synthesis, their distribution in linear sucrose gradient and the nature of their products. The enzymatic activities which incor­porated glucose from UDP-glucose or GDP-glucose at low substrate concentrations (10 -6 ᴍ) were both localized in membranes of a density of 1.129 g em-3 (Golgi membranes) and synthesized a β-1,4-glucan chain. Both showed similar properties in most of the characterization experiments. The glucosyltransferase that catalysed the formation of a β-1,3-glucan from UDP-glucose (0.48 mᴍ) was found in membranes which accumulated at a density of 1.170 g · cm-3 (plasma membrane) and differed in its properties from the Golgi-localized glucosyltransferase activities in many aspects. A soluble glucosyltransferase (175,000 × g supernatant) which was also active at low concentrations of UDP-glucose (10-6 ᴍ) but showed enhanced activity under conditions where the other glucosyltransferases were inactive incorporated glucose into a proteinase-sensi­tive product. In linear sucrose gradients this enzyme migrated to different gradient densities depending on conditions.

Influence of auxins on somatic embryogenesis and alkaloid accumulation in Leucojum aestivum callus

2013 ◽  
Vol 8 (6) ◽  
pp. 591-599 ◽  
Author(s):  
Agata Ptak ◽  
Anna Tahchy ◽  
Edyta Skrzypek ◽  
Tomasz Wójtowicz ◽  
Dominique Laurain-Mattar
Keyword(s):  
Somatic Embryogenesis ◽  
Somatic Embryo ◽  
Symptomatic Treatment ◽  
Dichlorophenoxyacetic Acid ◽  
Leucojum Aestivum ◽  
Anisic Acid ◽  
2,4 Dichlorophenoxyacetic Acid ◽  
Embryogenic Response

AbstractIn vitro cultures of Leucojum aestivum are considered as an alternative for the production of galanthamine, which is used for the symptomatic treatment of Alzheimer’s disease. We studied the effects of auxins 2,4-dichlorophenoxyacetic acid (2,4-D), 4-amino-3,5,6-trichloropicolinic acid (picloram), 3,6-dichloro-o-anisic acid (dicamba) at concentrations of 25 and 50 µM on the induction of embryogenic callus and its capacity to induce somatic embryogenesis and alkaloid accumulation. The embryogenic response of the explants was from 30% for 25 µM of dicamba to 100% for picloram (for both 25 and 50 µM). 2,4-D (50 µM) stimulated greater callus proliferation and somatic embryo induction as compared to the other auxins. Polyethylene glycol (PEG) stimulated somatic embryo maturation. Callus grown on media containing 50 µM of auxins produced fewer phenolic compounds as compared with callus grown on media containing 25 µM of auxins. GC-MS analyses showed seven alkaloids in the in vivo bulbs and two to four in callus culture. Galanthamine was detected in callus cultivated with 2,4-D (25, 50 µM), picloram (25 µM), and dicamba (50 µM). Other alkaloids, trisphaeridine, tazettine, and 11-hydroxyvittatine were accumulated only in callus growing on medium with picloram (50 µM).

In vivo micronucleus assays on 2,4-dichlorophenoxyacetic acid and its derivatives

1999 ◽  
Vol 444 (1) ◽  
pp. 227-234 ◽  
Author(s):  
Jeffrey M Charles ◽  
Helen C Cunny ◽  
Ronald D Wilson ◽  
James L Ivett ◽  
Hema Murli ◽  
...  
Keyword(s):  
Dichlorophenoxyacetic Acid ◽  
2,4 Dichlorophenoxyacetic Acid

scholarly journals Influence of Growth Regulators on Callogenesis and Somatic Embryo Development in Date Palm (Phoenix dactyliferaL.) Sahelian Cultivars

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Djibril Sané ◽  
Frédérique Aberlenc-Bertossi ◽  
Léopold Ibrahima Djitiningo Diatta ◽  
Badara Guèye ◽  
Abdourahman Daher ◽  
...  
Keyword(s):  
Nuclear Dna ◽  
Leaf Explants ◽  
Suspension Cultures ◽  
Naphthalene Acetic Acid ◽  
Dichlorophenoxyacetic Acid ◽  
Benzyl Adenine ◽  
Embryogenic Cell ◽  
Significant Difference ◽  
2,4 Dichlorophenoxyacetic Acid

This study provides a physiological analysis of somatic embryogenesis in four elite cultivars of date palms: Ahmar, Amsekhsi, Tijib, and Amaside, from the initial callogenesis to establishment and proliferation of embryogenic suspension cultures. Somatic embryos development and in vitro plants rooting were also studied. For each step, auxins and cytokinins concentrations were optimised. The primary callogenesis from leaf explants of seedlings appeared highly dependent on genotype. Ahmar (80%) and Amsekhsi (76%) appeared highly callogenic, whereas Tijib (10%) and Amaside (2%) produced low amounts of calluses. 2,4-Dichlorophenoxyacetic acid appeared favorable to the induction of primary callogenesis and its effect was enhanced by the addition of benzyl adenine or adenine sulfate. Secondary friable calli obtained from chopped granular calli were used to initiate embryogenic cell suspensions in media supplied with 2,4-dichlorophenoxyacetic acid. Suspension cultures showed a growth rate of fourfold after four subcultures in presence of 2,4-dichlorophenoxyacetic acid 2 mg/L. Our results showed that a seven-day transitory treatment with benzyl adenine 0,5 mg/L was necessary to optimize embryos development. Naphthalene acetic acid induced the development of primary orthogravitropic roots during embryos germination. The comparison with cytofluorometry of nuclear DNA amounts showed no significant difference in ploidy level between regenerated plants and seedlings.

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