TY - JOUR ID - 11556 TI - Metabolic profiling of oxylipins upon sorbitol treatment in barley leaves JO - Biochem. Soc. Trans. PY - 2001 SP - 861-862 AU - Weichert, H. AU - Kohlmann, M. AU - Wasternack, C. AU - Feussner, I. AU - VL - 28 UR - DO - 10.1042/bst0280861 AB - In barley leaves 13-lipoxygenases (LOXs) are induced by salicylate and jasmonate. Here, we analyse by metabolic profiling the accumulation of oxylipins upon sorbitol treatment. Although 13-LOX-derived products are formed and specifically directed into the reductase branch of the LOX pathway, accumulation is much later than in the cases of salicylate and jasmonate treatment. In addition, under these conditions only the accumulation of jasmonates as additional products of the LOX pathway has been found. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 11603 TI - Formation of 4-hydroxy-2-alkenals in barley leaves JO - Biochem. Soc. Trans. PY - 2000 SP - 850-851 AU - Weichert, H. AU - Kolbe, A. AU - Wasternack, C. AU - Feussner, I. AU - VL - 28 UR - DO - 10.1042/bst0280850 AB - In barley leaves 13-lipoxygenases are induced by jasmonates. This leads to induction of lipid peroxidation. Here we show by in vitro studies that these processes may further lead to autoxidative formation of (2E)-4-hydroxy-2-hexenal from (3Z)-hexenal. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 11710 TI - Nuclear Location of a Diadenosine 5′,5′”-P1,P4Tetraphosphate (Ap4A) Hydrolase in Tomato Cells Grown in Suspension Cultures JO - Bot. Acta PY - 1997 SP - 452-457 AU - Hause, B. AU - Feussner, K. AU - Wasternack, C. AU - VL - 110 UR - DO - 10.1111/j.1438-8677.1997.tb00662.x AB - Diadenosine 5′,5′”‐P1,P4‐tetraphosphate (Ap4A) cleaving enzymes are assumed to regulate intracellular levels of Ap4A, a compound known to affect cell proliferation and stress responses. From plants an Ap4A hydrolase was recently purified using tomato cells grown in suspension. It was partially sequenced and a peptide antibody was prepared (Feussner et al., 1996). Using this polyclonal monospecific antibody, an abundant nuclear location of Ap4A hydrolase in 4‐day‐old cells of atomato cell suspension culture is demonstrated here by means of immunocytochemical techniques using FITC (fluorescein‐5‐isothiocyanate) labeled secondary antibodies. The microscopic analysis of the occurrence of Ap4A hydrolase performed for different stages of the cell cycle visualized by parallel DAPI (4,6‐diamidino‐2‐phenylindole) staining revealed that the protein accumulates within nuclei of cells in the interphase, but is absent in the nucleus as well as cytoplasm during all stages of mitosis. This first intracellular localization of an Ap4A degrading enzyme within the nucleus and its pattern of appearance during the cell cycle is discussed in relation to the suggested role of Ap4A in triggering DNA synthesis and cell proliferation. A2 - C1 - Molecular Signal Processing; Cell and Metabolic Biology ER - TY - JOUR ID - 11700 TI - Induction of a new Lipoxygenase Form in Cucumber Leaves by Salicylic Acid or 2,6-Dichloroisonicotinic Acid JO - Bot. Acta PY - 1997 SP - 101-108 AU - Feussner, I. AU - Fritz, I. G. AU - Hause, B. AU - Ullrich, W. R. AU - Wasternack, C. AU - VL - 110 UR - DO - 10.1111/j.1438-8677.1997.tb00616.x AB - Changes in lipoxygenase (LOX) protein pattern and/or activity were investigated in relation to acquired resistance of cucumber (Cucumis sativus L.) leaves against two powdery mildews, Sphaerotheca fuliginea (Schlecht) Salmon and Erysiphe cichoracearum DC et Merat. Acquired resistance was established by spraying leaves with salicylic acid (SA) or 2,6‐dichloroisonicotinic acid (INA) and estimated in whole plants by infested leaf area compared to control plants. SA was more effective than INA. According to Western blots, untreated cucumber leaves contained a 97 kDa LOX form, which remained unchanged for up to 48 h after pathogen inoculation. Upon treatment with SA alone for 24 h or with INA plus pathogen, an additional 95 kDa LOX form appeared which had an isoelectric point in the alkaline range. For the induction of this form, a threshold concentration of 1 mM SA was required, higher SA concentrations did not change LOX‐95 expression which remained similar between 24 h and 96 h but further increased upon mildew inoculation. Phloem exudates contained only the LOX‐97 form, in intercellular washing fluid no LOX was detected. dichloroisonicotinic localization revealed LOX protein in the cytosol of the mesophyll cells without differences between the forms. A2 - C1 - Molecular Signal Processing; Cell and Metabolic Biology ER -