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Publikationen - Molekulare Signalverarbeitung

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Publikation

Wang, Q., Grubb, C.D. & Abel, S. Direct analysis of single leaf disks for chemopreventive glucosinolates Phytochem Anal 13, 152 - 157, (2002) DOI: 10.1002/pca.636

Natural isothiocyanates, produced during plant tissue damage from methionine-derived glucosinolates, are potent inducers of mammalian phase 2 detoxification enzymes such as quinone reductase (QR). A greatly simplified bioassay for glucosinolates based on induction and colorimetric detection of QR activity in murine hepatoma cells is described. It is demonstrated that excised leaf disks of Arabidopsis thaliana (ecotype Columbia) can directly and reproducibly substitute for cell-free leaf extracts as inducers of murine QR, which reduces sample preparation to a minimum and maximizes throughput. A comparison of 1 and 3 mm diameter leaf disks indicated that QR inducer potency was proportional to disk circumference (extent of tissue damage) rather than to area. When compared to the QR inducer potency of the corresponding amount of extract, 1 mm leaf disks were equally effective, whereas 3 mm disks were 70% as potent. The QR inducer potency of leaf disks correlated positively with the content of methionine-derived glucosinolates, as shown by the analysis of wild-type plants and mutant lines with lower or higher glucosinolate content. Thus, the microtitre plate-based assay of single leaf disks provides a robust and inexpensive visual method for rapidly screening large numbers of plants in mapping populations or mutant collections and may be applicable to other glucosinolate-producing species.

Publikation

Grubb, C.D., Gross, H.B., Chen, D.L. & Abel, S. Identification of Arabidopsis mutants with altered glucosinolate profiles based on isothiocyanate bioactivity Plant Sci 162, 143 - 152, (2002) DOI: 10.1016/S0168-9452(01)00550-7

Glucosinolates are a diverse class of nitrogen- and sulfur-containing secondary metabolites. They are rapidly hydrolyzed on tissue disruption to a number of biologically active compounds that are increasingly attracting interest as anticarcinogenic phytochemicals and crop protectants. Several glucosinolate-derived isothiocyanates are potent chemopreventive agents that favorably modulate carcinogen metabolism in mammals. Methylsulfinylalkyl isothiocyanates, in particular the 4-methylsulfinylbutyl derivative, are selective and potent inducers of mammalian detoxification enzymes such as quinone reductase (QR). Cruciferous plants including Arabidopsis thaliana (L.) Heyhn, synthesize methylsulfinylalkyl glucosinolates, which are derived from methionine. Using a colorimetric assay for QR activity in murine hepatoma cells and high performance liquid chromatography (HPLC) analysis of desulfoglucosinolates, we have demonstrated a strong positive correlation between leaf QR inducer potency and leaf content of methionine-derived glucosinolates in various A. thaliana ecotypes and available glucosinolate mutants. In a molecular genetic approach to glucosinolate biosynthesis, we screened 3000 chemically mutagenized M2 plants of the Columbia ecotype for altered leaf QR inducer potency. Subsequent HPLC analysis of progeny of putative mutants identified six lines with significant and heritable changes in leaf glucosinolate content and composition.

Publikation

Weichert, H., Kolbe, A., Kraus, A., Wasternack, C. & Feussner, I. Metabolic profiling of oxylipins in germinating cucumber seedlings - lipoxygenase-dependent degradation of triacylglycerols and biosynthesis of volatile aldehydes Planta 215, 612-619, (2002)

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Publikation

Schilling, S., Hoffmann, T., Rosche, F., Manhart, S., Wasternack, C. & Demuth, H.-U. Heterologous expression and characterization of human glutaminyl cyclase: evidence for a disulfide bond with importance for catalytic activity Biochemistry 41, 10849-10857, (2002)

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Publikation

Laskowski, M.J., Dreher, K.A., Gehring, M., Abel, S., Gensler, A. & Sussex, I.M. FQR1, a novel primary auxin-response gene, encodes an FMN-binding quinone reductase. Plant Physiology 128, 578-686, (2002)

FQR1 is a novel primary auxin-response gene that codes for a flavin mononucleotide-binding flavodoxin-like quinone reductase. Accumulation of FQR1 mRNA begins within 10 min of indole-3-acetic acid application and reaches a maximum of approximately 10-fold induction 30 min after treatment. This increase in FQR1 mRNA abundance is not diminished by the protein synthesis inhibitor cycloheximide, demonstrating thatFQR1 is a primary auxin-response gene. Sequence analysis reveals that FQR1 belongs to a family of flavin mononucleotide-binding quinone reductases. Partially purified His-tagged FQR1 isolated fromEscherichia coli catalyzes the transfer of electrons from NADH and NADPH to several substrates and exhibits in vitro quinone reductase activity. Overexpression of FQR1 in plants leads to increased levels of FQR1 protein and quinone reductase activity, indicating that FQR1 functions as a quinone reductase in vivo. In mammalian systems, glutathione S-transferases and quinone reductases are classified as phase II detoxification enzymes. We hypothesize that the auxin-inducible glutathioneS-transferases and quinone reductases found in plants also act as detoxification enzymes, possibly to protect against auxin-induced oxidative stress.

Publikation

Quint, M., Mihaljevic, R., Dussle, C.M., Xu, M.L., Melchinger, A.E. & Lübberstedt, T. Development of RGA-CAPS markers and genetic mapping of candidate genes for SCMV resistance in maize Theor Appl Genet 105, 355-366, (2002)

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Publikation

Feussner, I. & Wasternack, C. The lipoxygenase pathway Annu. Rev. Plant Biol. 53, 275-297, (2002)

Lipid peroxidation is common to all biological systems, both appearing in developmentally and environmentally regulated processes of plants. The hydroperoxy polyunsaturated fatty acids, synthesized by the action of various highly specialized forms of lipoxygenases, are substrates of at least seven different enzyme families. Signaling compounds such as jasmonates, antimicrobial and antifungal compounds such as leaf aldehydes or divinyl ethers, and a plant-specific blend of volatiles including leaf alcohols are among the numerous products. Cloning of many lipoxygenases and other key enzymes within the lipoxygenase pathway, as well as analyses by reverse genetic and metabolic profiling, revealed new reactions and the first hints of enzyme mechanisms, multiple functions, and regulation. These aspects are reviewed with respect to activation of this pathway as an initial step in the interaction of plants with pathogens, insects, or abiotic stress and at distinct stages of development.
Publikation

Ellis, C., Karafyllidis, I., Wasternack, C. & Turner, J.G. The Arabidopsis mutant cev1 links cell wall signaling to jasmonate and ethylene responses The Plant Cell 14, 1557-1566, (2002)

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Publikation

Nibbe, M., Hilpert, B., Wasternack, C., Miersch, O. & Apel, K. Cell death and salicylate- and jasmonate-dependent stress responses in Arabidopsis are controlled by single cet genes Planta 216, 120-128, (2002)

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Publikation

Abdala, G., Castro, G., Miersch, O. & Pierce, D. Changes in jasmonate and gibberellin levels during development of potato plants (Solanum tuberosum) Plant Growth Reg. 36, 121-126, (2002)

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