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Publikationen - Molekulare Signalverarbeitung

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Bücher und Buchkapitel

Möller, B.; Bürstenbinder, K.; Semi-Automatic Cell Segmentation from Noisy Image Data for Quantification of Microtubule Organization on Single Cell Level 199-203, (2019) ISBN: 978-1-5386-3641-1 DOI: 10.1109/ISBI.2019.8759145

The structure of the microtubule cytoskeleton provides valuable information related to morphogenesis of cells. The cytoskeleton organizes into diverse patterns that vary in cells of different types and tissues, but also within a single tissue. To assess differences in cytoskeleton organization methods are needed that quantify cytoskeleton patterns within a complete cell and which are suitable for large data sets. A major bottleneck in most approaches, however, is a lack of techniques for automatic extraction of cell contours. Here, we present a semi-automatic pipeline for cell segmentation and quantification of microtubule organization. Automatic methods are applied to extract major parts of the contours and a handy image editor is provided to manually add missing information efficiently. Experimental results prove that our approach yields high-quality contour data with minimal user intervention and serves a suitable basis for subsequent quantitative studies.
Bücher und Buchkapitel

Dorka, R.; Miersch, O.; Hause, B.; Weik, P.; Wasternack, C.; Chronobiologische Phänomene und Jasmonatgehalt bei Viscum album L. 49-66, (2009)

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Publikation

Guranowski, A.; Miersch, O.; Staswick, P. E.; Suza, W.; Wasternack, C.; Substrate specificity and products of side-reactions catalyzed by jasmonate:amino acid synthetase (JAR1) FEBS Lett. 581, 815-820, (2007) DOI: 10.1016/j.febslet.2007.01.049

Jasmonate:amino acid synthetase (JAR1) is involved in the function of jasmonic acid (JA) as a plant hormone. It catalyzes the synthesis of several JA‐amido conjugates, the most important of which appears to be JA‐Ile. Structurally, JAR1 is a member of the firefly luciferase superfamily that comprises enzymes that adenylate various organic acids. This study analyzed the substrate specificity of recombinant JAR1 and determined whether it catalyzes the synthesis of mono‐ and dinucleoside polyphosphates, which are side‐reaction products of many enzymes forming acyl ∼ adenylates. Among different oxylipins tested as mixed stereoisomers for substrate activity with JAR1, the highest rate of conversion to Ile‐conjugates was observed for (±)‐JA and 9,10‐dihydro‐JA, while the rate of conjugation with 12‐hydroxy‐JA and OPC‐4 (3‐oxo‐2‐(2Z ‐pentenyl)cyclopentane‐1‐butyric acid) was only about 1–2% that for (±)‐JA. Of the two stereoisomers of JA, (−)‐JA and (+)‐JA, rate of synthesis of the former was about 100‐fold faster than for (+)‐JA. Finally, we have demonstrated that (1) in the presence of ATP, Mg2+, (−)‐JA and tripolyphosphate the ligase produces adenosine 5′‐tetraphosphate (p4A); (2) addition of isoleucine to that mixture halts the p4A synthesis; (3) the enzyme produces neither diadenosine triphosphate (Ap3A) nor diadenosine tetraphosphate (Ap4A) and (4) Ap4A cannot substitute ATP as a source of adenylate in the complete reaction that yields JA‐Ile.
Bücher und Buchkapitel

Wasternack, C.; Hause, B.; Stenzel, I.; Goetz, S.; Feussner, I.; Miersch, O.; Jasmonate signaling in tomato – The input of tissue-specific occurrence of allene oxide cyclase and JA metabolites (Benning C., Ollrogge, J.). 107-111, (2007)

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Publikation

Bücking, H.; Förster, H.; Stenzel, I.; Miersch, O.; Hause, B.; Applied jasmonates accumulate extracellularly in tomato, but intracellularly in barley FEBS Lett. 562, 45-50, (2004) DOI: 10.1016/S0014-5793(04)00178-4

Jasmonic acid (JA) and its derivatives are well‐characterized signaling molecules in plant defense and development, but the site of their localization within plant tissue is entirely unknown. To address the question whether applied JA accumulates extracellularly or intracellularly, leaves of tomato and barley were fed with 14C‐labeled JA and the label was localized in cryofixed and lyophilized leaf tissues by microautoradiography. In tomato the radioactivity was detectable within the apoplast, but no label was found within the mesophyll cells. By contrast, in barley leaf tissues, radioactivity was detected within the mesophyll cells suggesting a cellular uptake of exogenously applied JA. JA, applied to leaves of both plants as in the labeling experiments, led in all leaf cells to the expression of JA‐inducible genes indicating that the perception is completed by JA signal transduction.
Bücher und Buchkapitel

Stumpe, M.; Stenzel, I.; Weichert, H.; Hause, B.; Feussner, I.; The Lipoxygenase Pathway in Mycorrhizal Roots of Medicago Truncatula 287-290, (2003) DOI: 10.1007/978-94-017-0159-4_67

Mycorrhizas are by far the most frequent occurring beneficial symbiotic interactions between plants and fungi. Species in >80% of extant plant families are capable of establishing an arbuscular mycorrhiza (AM). In relation to the development of the symbiosis the first molecular modifications are those associated with plant defense responses, which seem to be locally suppressed to levels compatible with symbiotic interaction (Gianinazzi-Pearson, 1996). AM symbiosis can, however, reduce root disease caused by several soil-borne pathogens. The mechanisms underlying this protective effect are still not well understood. In plants, products of the enzyme lipoxygenase (LOX) and the corresponding downstream enzymes, collectively named LOX pathway (Fig. 1B), are involved in wound healing, pest resistance, and signaling, or they have antimicrobial and antifungal activity (Feussner and Wasternack, 2002). The central reaction in this pathway is catalyzed by LOXs leading to formation of either 9- or 13-hydroperoxy octadeca(di/trien)oic acids (9/13-HPO(D/T); Brash, 1999). Thus LOXs may be divided into 9- and 13-LOXs (Fig. 1A). Seven different reaction branches within this pathway can use these hydroperoxy polyenoic fatty acids (PUFAs) leading to (i) keto PUFAs by a LOX; (ii) epoxy hydroxy-fatty acids by an epoxy alcohol synthase (EAS); (iii) octadecanoids and jasmonates via allene oxide synthase (AOS); (iv) leaf aldehydes and leaf alcohols via fatty acid hydroperoxide lyase (HPL); (v) hydroxy PUFAs (reductase); (vi) divinyl ether PUFAs via divinyl ether synthase (DES); and (vii) epoxy- or dihydrodiolPUFAs via peroxygenase (PDX; Feussner and Wasternack, 2002). AOS, HPL and DES belong to one subfamily of P450-containing enzymes, the CYP74 family (Feussner and Wasternack, 2002). Here, the involvement of this CYP74 enzyme family in mycorrhizal roots of M. truncatula during early stages of AM symbiosis formation was analyzed.
Publikation

Bohlmann, H.; Vignutelli, A.; Hilpert, B.; Miersch, O.; Wasternack, C.; Apel, K.; Wounding and chemicals induce expression of the Arabidopsis thaliana gene Thi2.1, encoding a fungal defense thionin, via the octadecanoid pathway FEBS Lett. 437, 281-286, (1998) DOI: 10.1016/S0014-5793(98)01251-4

In seedlings of Arabidopsis thaliana the thionin gene Thi2.1 is inducible by methyl jasmonate, wounding, silver nitrate, coronatine, and sorbitol. We have used a biochemical and genetic approach to test the signal transduction of these different inducers. Both exogenously applied jasmonates and jasmonates produced endogenously upon stress induction, lead to GUS expression in a Thi2.1 promoter-uidA transgenic line. No GUS expression was observed in a coi1 mutant background which lacks jasmonate perception whereas methyl jasmonate and coronatine but not the other inducers were able to overcome the block in jasmonic acid production in a fad3-2 fad7-2 fad8 mutant background. Our results show conclusively that all these inducers regulate Thi2-1 gene expression via the octadecanoid pathway.
Bücher und Buchkapitel

Kramell, R.; Porzel, A.; Miersch, O.; Schneider, G.; Characterization of Isoleucine Conjugates of Cucurbic Acid Isomers by Reversed-Phase and Chiral High-Performance Liquid Chromatography 77-78, (1998)

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Publikation

Kramell, R.; Miersch, O.; Hause, B.; Ortel, B.; Parthier, B.; Wasternack, C.; Amino acid conjugates of jasmonic acid induce jasmonate-responsive gene expression in barley (Hordeum vulgare L.) leaves FEBS Lett. 414, 197-202, (1997) DOI: 10.1016/S0014-5793(97)01005-3

Leaves of barley (Hordeum vulgare L. cv. Salome ) treated with jasmonic acid (JA), its methyl ester (JM), or its amino acid conjugates exhibit up‐regulation of specific genes and down‐regulation of house‐keeping genes. This transcriptional regulation exhibits several specificities. (i) The (−)‐enantiomers are more active, and conjugates are mainly active if they carry an l ‐amino acid moiety. (ii) The various JA‐responsive genes respond differentially to enantiomeric and chiralic forms. (iii) Both JA and its amino acid conjugates exhibiting no or negligible interconversion induce/repress genes.
Publikation

Hertel, S. C.; Knöfel, H.-D.; Kramell, R.; Miersch, O.; Partial purification and characterization of a jasmonic acid conjugate cleaving amidohydrolase from the fungus Botryodiplodia theobromae FEBS Lett. 407, 105-110, (1997) DOI: 10.1016/S0014-5793(97)00307-4

A protein preparation from the mycelium of the tropical pathogenic fungus Botryodiplodia theobromae revealed a novel peptidase activity. This enzyme was capable of cleaving conjugates of jasmonic acid with α-amino acids. The protein was enriched 108-fold by gel filtration, ion exchange and hydrophobic interaction chromatography. The enzyme was found to be a glycoprotein with a molecular mass of about 107 kDa. The amidohydrolase seems to be very specific with regard to (−)-jasmonic acid and α-amino acids with (S)-configuration.
  • Die Leibniz-Gemeinschaft
  • Digitalisierung in der Landwirtschaft
  • Martin-Luther Universität Halle
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