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Robert Scheuerlein - One of the best experts on this subject based on the ideXlab platform.
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germination in spores of Dryopteris filix mas regulation of rhizoid elongation as a second phytochrome mediated response
Physiologia Plantarum, 2008Co-Authors: Hiroko Yatsuhashi, Stefan Turnwald, Robert ScheuerleinAbstract:Spore germination in Dryopteris Filix-Mas occurs via a cascade of cellular responses, and chlorophyll formation, mitosis or rhizoid elongation are commonly used as parameters to determine spore germination. Detailed investigations of these parameters led to the hypothesis that they are regulated by different, independent phytochrome-mediated responses. This concept could be confirmed, as is described in this paper which demonstrates that perception of light via phytochrome occurs within two different phases separated in time. Presence of the far-red absorbing phytochrome form, Pfr, for 36 h, induces chlorophyll formation and the first unequal cell division, by which a rhizoid initial and a protonemal initial are formed (first phytochrome-mediated response). However, rhizoid elongation requires a second period of Pfr, presence (second phytochrome-mediated response). There is a clear temporal distinction between the first and the second phytochrome-mediated response with respect to the coupling of Pfr to the transduction chain; Pfr is unable to induce rhizoid growth until 60 h after the start of the first red irradiation. The effectivity of Pfr for inducing the second response shows an optimum at ca 96 h after the beginning of the presence of Pfr; thereafter, it declines slowly. The fluence-response relationship and the presence of red/far-red reversibility demonstrate that rhizoid elongation is a low-fluence response mediated by phytochrome and is independent of the first phytochrome response.
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Germination in spores of Dryopteris filix‐mas: Regulation of rhizoid elongation as a second phytochrome‐mediated response
Physiologia Plantarum, 2008Co-Authors: Hiroko Yatsuhashi, Stefan Turnwald, Robert ScheuerleinAbstract:Spore germination in Dryopteris Filix-Mas occurs via a cascade of cellular responses, and chlorophyll formation, mitosis or rhizoid elongation are commonly used as parameters to determine spore germination. Detailed investigations of these parameters led to the hypothesis that they are regulated by different, independent phytochrome-mediated responses. This concept could be confirmed, as is described in this paper which demonstrates that perception of light via phytochrome occurs within two different phases separated in time. Presence of the far-red absorbing phytochrome form, Pfr, for 36 h, induces chlorophyll formation and the first unequal cell division, by which a rhizoid initial and a protonemal initial are formed (first phytochrome-mediated response). However, rhizoid elongation requires a second period of Pfr, presence (second phytochrome-mediated response). There is a clear temporal distinction between the first and the second phytochrome-mediated response with respect to the coupling of Pfr to the transduction chain; Pfr is unable to induce rhizoid growth until 60 h after the start of the first red irradiation. The effectivity of Pfr for inducing the second response shows an optimum at ca 96 h after the beginning of the presence of Pfr; thereafter, it declines slowly. The fluence-response relationship and the presence of red/far-red reversibility demonstrate that rhizoid elongation is a low-fluence response mediated by phytochrome and is independent of the first phytochrome response.
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DETECTION AND PARTIAL SEQUENCE OF PHYTOCHROME GENES IN THE FERNS Anemia phyllitidis (L.)Sw (SCHIZAEACEAE) AND Dryopteris filix‐mas L. (POLYPODIACEAE) BY USING POLYMERASE‐CHAIN REACTION TECHNOLOGY*
Photochemistry and photobiology, 1992Co-Authors: Helmut P. Maucher, Robert Scheuerlein, Helmut SchraudolfAbstract:— Phytochrome controls several developmental steps during formation and differentiation of the fern gametophyte, including spore germination, morphogenesis of the gametophyte or differentiation of the sexual cells. To obtain information about the amino acid sequence and the regulation of phytochrome expression at the gene level, two degenerated oligonucleotides against well conserved amino acid regions were designed after an optimal alignment of the known phytochrome sequences. These primers were tested against DNA isolated from Arabidopsis thaliana, and the polymerase-chain reaction (PCR) products were cloned and sequenced. The DNA fragment produced with this method proved to be identical with a phytochrome-A-gene fragment from A. thaliana, and hence this fragment was used in further experiments to prove whether amplified DNA from fern species contains phytochrome-like DNA. With this procedure we successfully detected and cloned gene fragments both from gametophytes of Anemia phyllitidis and Dryopteris Filix-Mas, cultured for 7 days under vegetative conditions. In addition, poly(A)+ RNA was prepared from 7-day-old gametophytes of A. phyllitidis, induced to differentiate antheridia under generative conditions. This poly(A)+ RNA was transcribed into complementary DNA and used together with both phytochrome specific primers in a PCR experiment. We thereby obtained another DNA fragment. These data strongly suggest that A. phyllitidis has at least two phytochrome genes, and that at least one of them is expressed in light-grown gametophytes.
Oana Alexandra Drăghiceanu - One of the best experts on this subject based on the ideXlab platform.
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The Germination of Spores and Gametophyte Development in Ferns under Extracts Influence
Proceedings, 2019Co-Authors: Liliana Cristina Soare, Irina Fierăscu, Radu Claudiu Fierăscu, Codruța Mihaela Dobrescu, Alina Păunescu, Anca Nicoleta Șuțan, Oana Alexandra DrăghiceanuAbstract:The aim of this study was to establish the influence of ferns extracts (Asplenium scolopendrium and Dryopteris Filix-Mas) [...]
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STRESS RESPONSE TO NICKEL IN ASPLENIUM SCOLOPENDRIUM L. AND Dryopteris Filix-Mas (L.) SCHOTT.
Editura Universitatii din Pitesti, 2016Co-Authors: Oana Alexandra Drăghiceanu, Monica Popescu, Liliana Cristina SoareAbstract:The aim of this study was to determine the physiological response and the defensive potential in species Asplenium scolopendrium L. and Dryopteris Filix-Mas (L.) Schott under the action of nickel. The following experimental variants were tested: 0, 250, 500, 1000, 1500 mg Ni kg-1soil. One month, and three months respectively, after the initiation of the experiment, the amount of assimilating pigments was determined. One month after the initiation of the experiment, there were no significant differences between the variants with Ni and the control as far as the content of chlorophyll (a and b) and carotenoids was concerned. The results obtained three months after the inception of the experiment indicate that, at low concentrations, Ni stimulates the synthesis of chlorophyll. In the same period there occurred antioxidant mechanisms: increase in the amount of carotenoids and increased activity of catalase. In the species Dryopteris Filix-Mas, the variant with 1.000 mg Ni kg-1soil, the amount of chlorophyll was significantly reduced, and the catalase activity was 3 times higher than that obtained in the control group
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INFLUENCE OF HEAVY METALS ON GAMETOPHYTE DIFFERENTIATION IN TWO Dryopteris SPECIES IN ROMANIA’S FLORA
Editura Universitatii din Pitesti, 2015Co-Authors: Oana Alexandra Drăghiceanu, Liliana Cristina Soare, Codruţa Mihaela DobrescuAbstract:In this work we aimed to study the influence of Zn, Cu and Pb compounds on spore germination and gametophyte development in the species Dryopteris affinis (Lowe) Fraser-Jenkins and Dryopteris Filix-Mas (L.) Schott. The following initial variants were prepared: V1Cu 140 mg•L-1 Knop solution, V1Zn 300 mg•L-1 Knop solution, V1Pb 300 mg•L-1 Knop solution. From these variants we considered V2 and V32 as the concentrations, respectively, 5 and 10 times higher than the initial ones. The percentage of spores germinated was noted to decrease with the increase in the metal concentration in the solution so that there are significant differences between the control and metal variants; in some variants there was no germination reported: in V3Pb in both species and in V2Pb in the Dryopteris Filix-Mas. With regard to the gametophyte differentiation in very few variants, the stage of chordate prothallus was reached (C, V1Pb, V1Zn: in the two species). In V2 and V3, regardless of the species and metal, the spores and filaments turn to necrosis
R. Scheuerlein - One of the best experts on this subject based on the ideXlab platform.
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PHASE-SPECIFIC EFFECT OF NITRATE ON PHYTOCHROME-MEDIATED GERMINATION IN SPORES OF Dryopteris Filix-Mas L.*
Photochemistry and Photobiology, 1990Co-Authors: C. J. Haas, R. ScheuerleinAbstract:— Induction of germination in spores of Dryopteris Filix-Mas L. shows an absolute requirement for light with phytochrome as photoreceptor. The effectiveness of a red light (R) irradiation is affected by the ionic composition of the culture medium (Haupt, Planta164,63–68, 1985). In this paper NO3−is identified as the component mediating this effect whereas ammonium or organic nitrogen-containing compounds, tested so far, are ineffective. Enhancement by NO3− can be observed at concentrations 1 μM and an optimum is found around 1 mM. The kinetics of NO3− action are elucidated by restricting the presence of NO3− to defined periods after sowing, and they are compared with kinetics of Pfr action. As a result, the enhancement of NO3− can be attributed to a specific phase in the signal-transduction chain: the promotive effect of nitrate is only obtained if the Pfr presence coincides with or slightly preceeds the presence of NO3−. If Pfr can act for 15 or 20 h and is reversed thereafter by far-red light (FR), NO3− added during this period or immediately after FR is effective and this enhancement vanishes during 6 h following FR. In contrast, NO3− has no effect as long as it is applied only during a period before Pfr is formed. Moreover, a modulation of the effectiveness of the photoconversion Pr to Pfr by NO3− can be excluded. These results are interpreted by the action of NO3− during early steps in the Pfr-induced signal-transduction chain. However, an additional effect of NO3− on the “coupling” of Pfr itself to subsequent dark reactions cannot be excluded yet.
David Gani - One of the best experts on this subject based on the ideXlab platform.
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L-Methionine decarboxylase from Dryopteris Filix-Mas: purification, characterization, substrate specificity, abortive transamination of the coenzyme, and stereochemical courses of substrate decarboxylation and coenzyme transamination
Biochemistry, 1990Co-Authors: David E. Stevenson, Mahmoud Akhtar, David GaniAbstract:L-Methionine decarboxylase from the male fern Dryopteris Filix-Mas has been purified 256-fold from acetone powder extracts to very near homogeneity. The enzyme is membrane-associated and requires detergent for solubilization during the initial extraction. The enzyme is a homodimer of subunit M{sub r} 57,000 and shows a pH optimum at {approximately} 5.0 with 20 mM (2S)-methionine as substrate. A wide range of straight- and branched-chain (2S)-alkylamino acids are substrates for the enzyme. The values for the rate of decarboxylation, V{sub max}, and for the apparent Michaelis constant, K{sub m}, however, vary with structure and with the chirality at C-3. The pH dependence of V and V/K has been examined for three substrates: (2S)-methionine, valine, and leucine. The occurrence of the abortive reaction was confirmed by showing that ({sup 35}S)methionine is converted to labeled 3-(methylthio)propionaldehyde while (4{prime}-{sup 3}H)PLP is converted to labeled pyridoxamine 5{prime}-phosphate (PMP). The decarboxylation of (2S)-methionine gave 3(methylthio)-1-aminopropane. Preparation of the N-camphanamide derivative of the amine allowed the C-1 methylene protons to be distinguished by {sup 1}H NMR spectroscopy. Synthetic samples of the camphanamide were prepared in which each of the C-1 methylene protons was replaced by deuterium. When tritiated pyridoxal phosphate was incubated with the enzyme, tritiated pyridoxaminemore » phosphate was formed. These results are used to construct possible mechanistic schemes for both reactions, decarboxylation and transamination. The position and possible identities of active-site proton donors are discussed.« less
Hiroko Yatsuhashi - One of the best experts on this subject based on the ideXlab platform.
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germination in spores of Dryopteris filix mas regulation of rhizoid elongation as a second phytochrome mediated response
Physiologia Plantarum, 2008Co-Authors: Hiroko Yatsuhashi, Stefan Turnwald, Robert ScheuerleinAbstract:Spore germination in Dryopteris Filix-Mas occurs via a cascade of cellular responses, and chlorophyll formation, mitosis or rhizoid elongation are commonly used as parameters to determine spore germination. Detailed investigations of these parameters led to the hypothesis that they are regulated by different, independent phytochrome-mediated responses. This concept could be confirmed, as is described in this paper which demonstrates that perception of light via phytochrome occurs within two different phases separated in time. Presence of the far-red absorbing phytochrome form, Pfr, for 36 h, induces chlorophyll formation and the first unequal cell division, by which a rhizoid initial and a protonemal initial are formed (first phytochrome-mediated response). However, rhizoid elongation requires a second period of Pfr, presence (second phytochrome-mediated response). There is a clear temporal distinction between the first and the second phytochrome-mediated response with respect to the coupling of Pfr to the transduction chain; Pfr is unable to induce rhizoid growth until 60 h after the start of the first red irradiation. The effectivity of Pfr for inducing the second response shows an optimum at ca 96 h after the beginning of the presence of Pfr; thereafter, it declines slowly. The fluence-response relationship and the presence of red/far-red reversibility demonstrate that rhizoid elongation is a low-fluence response mediated by phytochrome and is independent of the first phytochrome response.
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Germination in spores of Dryopteris filix‐mas: Regulation of rhizoid elongation as a second phytochrome‐mediated response
Physiologia Plantarum, 2008Co-Authors: Hiroko Yatsuhashi, Stefan Turnwald, Robert ScheuerleinAbstract:Spore germination in Dryopteris Filix-Mas occurs via a cascade of cellular responses, and chlorophyll formation, mitosis or rhizoid elongation are commonly used as parameters to determine spore germination. Detailed investigations of these parameters led to the hypothesis that they are regulated by different, independent phytochrome-mediated responses. This concept could be confirmed, as is described in this paper which demonstrates that perception of light via phytochrome occurs within two different phases separated in time. Presence of the far-red absorbing phytochrome form, Pfr, for 36 h, induces chlorophyll formation and the first unequal cell division, by which a rhizoid initial and a protonemal initial are formed (first phytochrome-mediated response). However, rhizoid elongation requires a second period of Pfr, presence (second phytochrome-mediated response). There is a clear temporal distinction between the first and the second phytochrome-mediated response with respect to the coupling of Pfr to the transduction chain; Pfr is unable to induce rhizoid growth until 60 h after the start of the first red irradiation. The effectivity of Pfr for inducing the second response shows an optimum at ca 96 h after the beginning of the presence of Pfr; thereafter, it declines slowly. The fluence-response relationship and the presence of red/far-red reversibility demonstrate that rhizoid elongation is a low-fluence response mediated by phytochrome and is independent of the first phytochrome response.
