TY - JOUR A1 - Münch, Miriam A1 - Hsin, Chih-Hsuan A1 - Ferber, Elena A1 - Berger, Susanne A1 - Müller, Martin J. T1 - Reactive electrophilic oxylipins trigger a heat stress-like response through HSFA1 transcription factors JF - Journal of Experimental Botany N2 - Electrophilic oxylipins trigger a heat-shock-like response in the absence of heat through the canonical heat-shock transcription factor A1, thereby helping to cope with stresses associated with protein damage.Abiotic and biotic stresses are often characterized by an induction of reactive electrophile species (RES) such as the jasmonate 12-oxo-phytodienoic acid (OPDA) or the structurally related phytoprostanes. Previously, RES oxylipins have been shown massively to induce heat-shock-response (HSR) genes including HSP101 chaperones. Moreover, jasmonates have been reported to play a role in basal thermotolerance. We show that representative HSR marker genes are strongly induced by RES oxylipins through the four master regulator transcription factors HSFA1a, b, d, and e essential for short-term adaptation to heat stress in Arabidopsis. When compared with Arabidopsis seedlings treated at the optimal acclimation temperature of 37 A degrees C, the exogenous application of RES oxylipins at 20 A degrees C induced a much weaker induction of HSP101 at both the gene and protein expression levels which, however, was not sufficient to confer short-term acquired thermotolerance. Moreover, jasmonate-deficient mutant lines displayed a wild-type-like HSR and were not compromised in acquiring thermotolerance. Hence, the OPDA- and RES oxylipin-induced HSR is not sufficient to protect seedlings from severe heat stress but may help plants to cope better with stresses associated with protein unfolding by inducing a battery of chaperones in the absence of heat. KW - arabidopsis-thaliana KW - shock response KW - gene-expression KW - model KW - acquired thermotolerance KW - 12-oxo-phytodienoic acid KW - thermotolerance KW - plants KW - detoxification KW - acquisition KW - activation KW - heat stress KW - jasmonates KW - phytoprostanes KW - reactive electrophilic species KW - unfolded protein response Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-186766 VL - 67 IS - 21 ER - TY - JOUR A1 - Joensuu, Johanna A1 - Altimir, Nuria A1 - Hakola, Hannele A1 - Rostás, Michael A1 - Raivonen, Maarit A1 - Vestenius, Mika A1 - Aaltonen, Hermanni A1 - Riederer, Markus A1 - Bäck, Jaana T1 - Role of needle surface waxes in dynamic exchange of mono- and sesquiterpenes JF - Atmospheric Chemistry and Physics N2 - Biogenic volatile organic compounds (BVOCs) produced by plants have a major role in atmospheric chemistry. The different physicochemical properties of BVOCs affect their transport within and out of the plant as well as their reactions along the way. Some of these compounds may accumulate in or on the waxy surface layer of conifer needles and participate in chemical reactions on or near the foliage surface. The aim of this work was to determine whether terpenes, a key category of BVOCs produced by trees, can be found on the epicuticles of Scots pine (Pinus sylvestris L.) and, if so, how they compare with the terpenes found in shoot emissions of the same tree. We measured shoot-level emissions of pine seedlings at a remote outdoor location in central Finland and subsequently analysed the needle surface waxes for the same compounds. Both emissions and wax extracts were clearly dominated by monoterpenes, but the proportion of sesquiterpenes was higher in the wax extracts. There were also differences in the terpene spectra of the emissions and the wax extracts. The results, therefore, support the existence of BVOC associated to the epicuticular waxes. We briefly discuss the different pathways for terpenes to reach the needle surfaces and the implications for air chemistry. KW - needle surface waxes KW - biogenic volatile organic compounds KW - Pinus sylvestris L. KW - atmospheric chemistry Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-171324 VL - 16 IS - 12 ER - TY - JOUR A1 - Vendelova, Emilia A1 - de Lima, Jeferson Camargo A1 - Lorenzatto, Karina Rodrigues A1 - Monteiro, Karina Mariante A1 - Mueller, Thomas A1 - Veepaschit, Jyotishman A1 - Grimm, Clemens A1 - Brehm, Klaus A1 - Hrčková, Gabriela A1 - Lutz, Manfred B. A1 - Ferreira, Henrique B. A1 - Nono, Justin Komguep T1 - Proteomic Analysis of Excretory-Secretory Products of Mesocestoides corti Metacestodes Reveals Potential Suppressors of Dendritic Cell Functions JF - PLoS Neglected Tropical Diseases N2 - Accumulating evidences have assigned a central role to parasite-derived proteins in immunomodulation. Here, we report on the proteomic identification and characterization of immunomodulatory excretory-secretory (ES) products from the metacestode larva (tetrathyridium) of the tapeworm Mesocestoides corti (syn. M. vogae). We demonstrate that ES products but not larval homogenates inhibit the stimuli-driven release of the pro-inflammatory, Th1-inducing cytokine IL-12p70 by murine bone marrow-derived dendritic cells (BMDCs). Within the ES fraction, we biochemically narrowed down the immunosuppressive activity to glycoproteins since active components were lipid-free, but sensitive to heat- and carbohydrate-treatment. Finally, using bioassay-guided chromatographic analyses assisted by comparative proteomics of active and inactive fractions of the ES products, we defined a comprehensive list of candidate proteins released by M. corti tetrathyridia as potential suppressors of DC functions. Our study provides a comprehensive library of somatic and ES products and highlight some candidate parasite factors that might drive the subversion of DC functions to facilitate the persistence of M. corti tetrathyridia in their hosts. KW - proteomic analysis KW - excretory-secretory KW - Mesocestoides corti Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-166742 VL - 10 IS - 10 ER - TY - JOUR A1 - Palamides, Pia A1 - Jodeleit, Henrika A1 - Föhlinger, Michael A1 - Beigel, Florian A1 - Herbach, Nadja A1 - Mueller, Thomas A1 - Wolf, Eckhard A1 - Siebeck, Matthias A1 - Gropp, Roswitha T1 - A mouse model for ulcerative colitis based on NOD-scid IL2R gamma(null) mice reconstituted with peripheral blood mononuclear cells from affected individuals JF - Disease Models & Mechanisms N2 - Animal models reflective of ulcerative colitis (UC) remain a major challenge, and yet are crucial to understand mechanisms underlying the onset of disease and inflammatory characteristics of relapses and remission. Mouse models in which colitis-like symptoms are induced through challenge with toxins such as oxazolone, dextran sodium sulfate (DSS) or 2,4,6-trinitrobenzenesulfonic acid (TNBS) have been instrumental in understanding the inflammatory processes of UC. However, these neither reflect the heterogeneous symptoms observed in the UC-affected population nor can they be used to test the efficacy of inhibitors developed against human targets where high sequence and structural similarity of the respective ligands is lacking. In an attempt to overcome these problems, we have developed a mouse model that relies on NOD-scid IL2R γnull mice reconstituted with peripheral blood mononuclear cells derived from UC-affected individuals. Upon challenge with ethanol, mice developed colitis-like symptoms and changes in the colon architecture, characterized by influx of inflammatory cells, edema, crypt loss, crypt abscesses and epithelial hyperplasia, as previously observed in immune-competent mice. TARC, TGFβ1 and HGF expression increased in distal parts of the colon. Analysis of human leucocytes isolated from mouse spleen revealed an increase in frequencies of CD1a+, CD64+, CD163+ and TSLPR+ CD14+ monocytes, and antigen-experienced CD44+ CD4+ and CD8+ T-cells in response to ethanol. Analysis of human leucocytes from the colon of challenged mice identified CD14+ monocytes and CD11b+ monocytes as the predominant populations. Quantitative real-time PCR (RT-PCR) analysis from distal parts of the colon indicated that IFNγ might be one of the cytokines driving inflammation. Treatment with infliximab ameliorated symptoms and pathological manifestations, whereas pitrakinra had no therapeutic benefit. Thus, this model is partially reflective of the human disease and might help to increase the translation of animal and clinical studies. KW - animal models KW - Ulcerative colitis KW - NSG mice KW - Infliximab KW - Pitrakinra Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-164946 VL - 9 ER - TY - JOUR A1 - Walper, Elisabeth A1 - Weiste, Christoph A1 - Mueller, Martin J. A1 - Hamberg, Mats A1 - Dröge-Laser, Wolfgang T1 - Screen Identifying Arabidopsis Transcription Factors Involved in the Response to 9-Lipoxygenase-Derived Oxylipins JF - PLoS One N2 - 13-Lipoxygenase-derived oxylipins, such as jasmonates act as potent signaling molecules in plants. Although experimental evidence supports the impact of oxylipins generated by the 9-Lipoxygenase (9-LOX) pathway in root development and pathogen defense, their signaling function in plants remains largely elusive. Based on the root growth inhibiting properties of the 9-LOX-oxylipin 9-HOT (9-hydroxy-10,12,15-octadecatrienoic acid), we established a screening approach aiming at identifying transcription factors (TFs) involved in signaling and/or metabolism of this oxylipin. Making use of the AtTORF-Ex (Arabidopsis thaliana Transcription Factor Open Reading Frame Expression) collection of plant lines overexpressing TF genes, we screened for those TFs which restore root growth on 9-HOT. Out of 6,000 lines, eight TFs were recovered at least three times and were therefore selected for detailed analysis. Overexpression of the basic leucine Zipper (bZIP) TF TGA5 and its target, the monoxygenase CYP81D11 reduced the effect of added 9-HOT, presumably due to activation of a detoxification pathway. The highly related ETHYLENE RESPONSE FACTORs ERF106 and ERF107 induce a broad detoxification response towards 9-LOX-oxylipins and xenobiotic compounds. From a set of 18 related group S-bZIP factors isolated in the screen, bZIP11 is known to participate in auxin-mediated root growth and may connect oxylipins to root meristem function. The TF candidates isolated in this screen provide starting points for further attempts to dissect putative signaling pathways involving 9-LOX-derived oxylipins. KW - Jasmonic acid KW - root growth KW - arabidopsis thaliana KW - detoxification KW - seedlings KW - stress signaling cascade KW - hyperexpression techniques KW - ranscription factors Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-146857 VL - 11 IS - 4 ER - TY - JOUR A1 - Zhu, Min A1 - Shabala, Lana A1 - Cuin, Tracey A. A1 - Huang, Xin A1 - Zhou, Meixue A1 - Munns, Rana A1 - Shabala, Sergey T1 - Nax loci affect SOS1-like Na\(^+\)/H\(^+\) exchanger expression and activity in wheat JF - Journal of Experimental Botany N2 - Salinity stress tolerance in durum wheat is strongly associated with a plant's ability to control Na\(^+\) delivery to the shoot. Two loci, termed Nax1 and Nax2, were recently identified as being critical for this process and the sodium transporters HKT1;4 and HKT1; 5 were identified as the respective candidate genes. These transporters retrieve Na\(^+\) from the xylem, thus limiting the rates of Na\(^+\) transport from the root to the shoot. In this work, we show that the Nax loci also affect activity and expression levels of the SOS1-like Na\(^+\)/H\(^+\) exchanger in both root cortical and stelar tissues. Net Na\(^+\) efflux measured in isolated steles from salt-treated plants, using the non-invasive ion flux measuring MIFE technique, decreased in the sequence: Tamaroi (parental line)>Nax1=Nax2>Nax1:Nax2 lines. This efflux was sensitive to amiloride (a known inhibitor of the Na\(^+\)/H\(^+\) exchanger) and was mirrored by net H\(^+\) flux changes. TdSOS1 relative transcript levels were 6-10-fold lower in Nax lines compared with Tamaroi. Thus, it appears that Nax loci confer two highly complementary mechanisms, both of which contribute towards reducing the xylem Na\(^+\) content. One enhances the retrieval of Na\(^+\) back into the root stele via HKT1;4 or HKT1;5, whilst the other reduces the rate of Na\(^+\) loading into the xylem via SOS1. It is suggested that such duality plays an important adaptive role with greater versatility for responding to a changing environment and controlling Na\(^+\) delivery to the shoot. KW - HKT transporter KW - potassium KW - salinity stress KW - sequestration KW - sodium KW - xylem loading Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-190908 VL - 67 IS - 3 ER - TY - JOUR A1 - Chopra, Martin A1 - Biehl, Marlene A1 - Steinfatt, Tim A1 - Brandl, Andreas A1 - Kums, Juliane A1 - Amich, Jorge A1 - Vaeth, Martin A1 - Kuen, Janina A1 - Holtappels, Rafaela A1 - Podlech, Jürgen A1 - Mottok, Anja A1 - Kraus, Sabrina A1 - Jordán-Garotte, Ana-Laura A1 - Bäuerlein, Carina A. A1 - Brede, Christian A1 - Ribechini, Eliana A1 - Fick, Andrea A1 - Seher, Axel A1 - Polz, Johannes A1 - Ottmueller, Katja J. A1 - Baker, Jeannette A1 - Nishikii, Hidekazu A1 - Ritz, Miriam A1 - Mattenheimer, Katharina A1 - Schwinn, Stefanie A1 - Winter, Thorsten A1 - Schäfer, Viktoria A1 - Krappmann, Sven A1 - Einsele, Hermann A1 - Müller, Thomas D. A1 - Reddehase, Matthias J. A1 - Lutz, Manfred B. A1 - Männel, Daniela N. A1 - Berberich-Siebelt, Friederike A1 - Wajant, Harald A1 - Beilhack, Andreas T1 - Exogenous TNFR2 activation protects from acute GvHD via host T reg cell expansion JF - Journal of Experimental Medicine N2 - Donor CD4\(^+\)Foxp3\(^+\) regulatory T cells (T reg cells) suppress graft-versus-host disease (GvHD) after allogeneic hematopoietic stem cell transplantation (HCT allo-HCT]). Current clinical study protocols rely on the ex vivo expansion of donor T reg cells and their infusion in high numbers. In this study, we present a novel strategy for inhibiting GvHD that is based on the in vivo expansion of recipient T reg cells before allo-HCT, exploiting the crucial role of tumor necrosis factor receptor 2 (TNFR2) in T reg cell biology. Expanding radiation-resistant host T reg cells in recipient mice using a mouse TNFR2-selective agonist before allo-HCT significantly prolonged survival and reduced GvHD severity in a TNFR2-and T reg cell-dependent manner. The beneficial effects of transplanted T cells against leukemia cells and infectious pathogens remained unaffected. A corresponding human TNFR2-specific agonist expanded human T reg cells in vitro. These observations indicate the potential of our strategy to protect allo-HCT patients from acute GvHD by expanding T reg cells via selective TNFR2 activation in vivo. KW - Tumor-necrosis-factor KW - Regulatory-cells KW - Bone marrow transplantantation KW - Graft-versus-leukemia KW - Rheumatoid arthritis KW - Autoimmune diseases KW - Factor receptor KW - Alpha therapy KW - Expression KW - Suppression Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-187640 VL - 213 IS - 9 ER - TY - JOUR A1 - Horn, Hannes A1 - Keller, Alexander A1 - Hildebrandt, Ulrich A1 - Kämpfer, Peter A1 - Riederer, Markus A1 - Hentschel, Ute T1 - Draft genome of the \(Arabidopsis\) \(thaliana\) phyllosphere bacterium, \(Williamsia\) sp. ARP1 JF - Standards in Genomic Sciences N2 - The Gram-positive actinomycete \(Williamsia\) sp. ARP1 was originally isolated from the \(Arabidopsis\) \(thaliana\) phyllosphere. Here we describe the general physiological features of this microorganism together with the draft genome sequence and annotation. The 4,745,080 bp long genome contains 4434 protein-coding genes and 70 RNA genes. To our knowledge, this is only the second reported genome from the genus \(Williamsia\) and the first sequenced strain from the phyllosphere. The presented genomic information is interpreted in the context of an adaptation to the phyllosphere habitat. KW - arabidopsis thaliana KW - whole genome sequencing KW - adaption KW - Williamsia sp. ARP1 KW - phyllosphere KW - draft genome KW - next generation sequencing KW - assembly KW - annotation Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-146008 VL - 11 IS - 8 ER - TY - JOUR A1 - Böhm, Jennifer A1 - Scherzer, Sönke A1 - Krol, Elzbieta A1 - Kreuzer, Ines A1 - von Meyer, Katharina A1 - Lorey, Christian A1 - Mueller, Thomas D. A1 - Shabala, Lana A1 - Monte, Isabel A1 - Salano, Roberto A1 - Al-Rasheid, Khaled A. S. A1 - Rennenberg, Heinz A1 - Shabala, Sergey A1 - Neher, Erwin A1 - Hedrich, Rainer T1 - The Venus Flytrap Dionaea muscipula Counts Prey-Induced Action Potentials to Induce Sodium Uptake JF - Current Biology N2 - Carnivorous plants, such as the Venus flytrap (Dionaea muscipula), depend on an animal diet when grown in nutrient-poor soils. When an insect visits the trap and tilts the mechanosensors on the inner surface, action potentials (APs) are fired. After a moving object elicits two APs, the trap snaps shut, encaging the victim. Panicking preys repeatedly touch the trigger hairs over the subsequent hours, leading to a hermetically closed trap, which via the gland-based endocrine system is flooded by a prey-decomposing acidic enzyme cocktail. Here, we asked the question as to how many times trigger hairs have to be stimulated (e.g., now many APs are required) for the flytrap to recognize an encaged object as potential food, thus making it worthwhile activating the glands. By applying a series of trigger-hair stimulations, we found that the touch hormone jasmonic acid (JA) signaling pathway is activated after the second stimulus, while more than three APs are required to trigger an expression of genes encoding prey-degrading hydrolases, and that this expression is proportional to the number of mechanical stimulations. A decomposing animal contains a sodium load, and we have found that these sodium ions enter the capture organ via glands. We identified a flytrap sodium channel DmHKT1 as responsible for this sodium acquisition, with the number of transcripts expressed being dependent on the number of mechano-electric stimulations. Hence, the number of APs a victim triggers while trying to break out of the trap identifies the moving prey as a struggling Na+-rich animal and nutrition for the plant. KW - Venusfliegenfalle KW - Dionaea muscipula Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-128054 VL - 26 IS - 3 ER - TY - THES A1 - Asmus, Elisabeth T1 - Mode of Action of Adjuvants for Foliar Application T1 - Wirkmechanismen von Adjuvantien für die Blattflächenapplikation N2 - Adjuvants are compounds added to an agrochemical spray formulation to improve or modify the action of an active ingredient (AI) or the physico-chemical characteristics of the spray liquid. Adjuvants can have more than only one distinct mode of action (MoA) during the foliar spray application process and they are generally known to be the best tools to improve agrochemical formulations. The main objective for this work was to elucidate the basic MoA of adjuvants by uncoupling different aspects of the spray application. Laboratory experiments, beginning from retention and spreading characteristics, followed by humectant effects concerning the spray deposit on the leaf surface and ultimately the cuticular penetration of an AI, were figured out to evaluate overall in vivo effects of adjuvants which were also obtained in a greenhouse spray test. For this comprehensive study, the surfactant classes of non-ionic sorbitan esters (Span), polysorbates (Tween) and oleyl alcohol polyglycol ether (Genapol O) were generally considered because of their common promoting potential in agrochemical formulations and their structural diversity. The reduction of interfacial tension is one of the most crucial physico-chemical properties of surfactants. The dynamic surface tension (DST) was monitored to characterise the surface tension lowering behaviour which is known to influence the droplet formation and retention characteristics. The DST is a function of time and the critical time frame of droplet impact might be at about 100 ms. None of the selected surfactants were found to lower the surface tension sufficiently during this short timeframe (chapter I). At ca. 100 ms, Tween 20 resulted in the lowest DST value. When surfactant monomers are fully saturated at the droplet-air-interface, an equilibrium surface tension (STeq) value can be determined which may be used to predict spreading or run-off effects. The majority of selected surfactants resulted in a narrow distribution of STeq values, ranging between 30 and 45 mN m- 1. Nevertheless, all surfactants were able to decrease the surface tension considerably compared to pure water (72 mN m- 1). The influence of different surfactants on the wetting process was evaluated by studying time-dependent static contact angles on different surfaces and the droplet spread area on Triticum aestivum leaves after water evaporation. The spreading potential was observed to be better for Spans than for Tweens. Especially Span 20 showed maximum spreading results. To transfer laboratory findings to spray application, related to field conditions, retention and leaf coverage was measured quantitatively on wheat leaves by using a variable track sprayer. Since the retention process involves short time dynamics, it is well-known that the spray retention on a plant surface is not correlated to STeq but to DST values. The relationship between DST at ca. 100 ms and results from the track sprayer showed increasing retention results with decreasing DST, whereas at DST values below ca. 60 mN m- 1 no further retention improvement could be observed. Under field conditions, water evaporates from the droplet within a few seconds to minutes after droplet deposition on the leaf surface. Since precipitation of the AI must essentially being avoided by holding the AI in solution, so-called humectants are used as tank-mix adjuvants. The ability of pure surfactants to absorb water from the surrounding atmosphere was investigated comprehensively by analysing water sorption isotherms (chapter II). These isotherms showed an exponential shape with a steep water sorption increase starting at 60% to 70% RH. Water sorption was low for Spans and much more distinct for the polyethoxylated surfactants (Tweens and Genapol O series). The relationship between the water sorption behaviour and the molecular structure of surfactants was considered as the so-called humectant activity. With an increasing ethylene oxide (EO) content, the humectant activity increased concerning the particular class of Genapol O. However, it could be shown that the moisture absorption across all classes of selected surfactants correlates rather better with their hydrophilic-lipophilic balance values with the EO content. All aboveground organs of plants are covered by the cuticular membrane which is therefore the first rate limiting barrier for AI uptake. In vitro penetration experiments through an astomatous model cuticle were performed to study the effects of adjuvants on the penetration of the lipophilic herbicide Pinoxaden (PXD) (chapter III). In order to understand the influence of different adjuvant MoA like humectancy, experiments were performed under three different humidity levels. No explicit relationship could be found between humidity levels and the PXD penetration which might be explained by the fact that humidity effects would rather affect hydrophilic AIs than lipophilic ones. Especially for Tween 20, it became obvious that a complex balance between multiple MoA like spreading, humectancy and plasticising effects have to be considered. Greenhouse trials, focussing the adjuvant impact on in vivo action of PXD, were evaluated on five different grass-weed species (chapter III). Since agrochemical spray application and its following action on living plants also includes translocation processes in planta and species dependent physiological effects, this investigation may help to simulate the situation on the field. Even though the absolute weed damage was different, depending both on plant species and also on PXD rates, adjuvant effects in greenhouse experiments displayed the same ranking as in cuticular penetration studies: Tween 20 > Tween 80 > Span 20 ≥ Span 80. Thus, the present work shows for the first time that findings obtained in laboratory experiments can be successfully transferred to spray application studies on living plants concerning adjuvant MoA. A comparative analysis, using radar charts, could demonstrate systematic derivations from structural similarities of adjuvants to their MoA (summarising discussion and outlook). Exemplarily, Tween 20 and Tween 80 cover a wide range of selected variables by having no outstanding MoA improving one distinct process during foliar application, compared to non-ethoxylated Span 20 and Span 80 which primarily revealed a surface active action. Most adjuvants used in this study represent polydisperse mixtures bearing a complex distribution of EO and aliphatic chains. From this study it seems alike that adjuvants having a wide EO distribution offer broader potential than adjuvants with a small EO distribution. It might be a speculation that due to this broad distribution of single molecules, all bearing their individual specific physico-chemical nature, a wide range of properties concerning their MoA is covered. N2 - Adjuvantien sind chemische Verbindungen, die einer Pflanzenschutzformulierung hinzugefügt werden, um die Wirkung der Aktivsubstanz oder die physikalisch-chemischen Eigenschaften der Spritzbrühe zu verbessern oder zu modifizieren. Sie können mehr als nur einen einzigen bestimmten Wirkmechanismus während der Blattflächenapplikation aufweisen, sodass sie gemeinhin als wirksamste Hilfsmittel in Pflanzenschutzformulierungen benutzt werden. Der Schwerpunkt dieser Arbeit lag darauf, ihre wesentlichen Wirkmechanismen aufzuklären, indem verschiedene Aspekte der Applikation entkoppelt und unabhängig voneinander untersucht wurden. Hierzu wurden Laborversuche durchgeführt, beginnend mit dem Retentions- und Spreitungsverhalten, über die „humectant“- Eigenschaft, den Tropfenrückstand betreffend und schließlich die kutikuläre Penetration einer Aktivsubstanz. Um schlussendlich die ineinander übergreifenden in vivo Mechanismen von Adjuvantien zusammenfassend bewerten zu können, wurde zusätzlich ein Gewächshausprayversuch ausgeführt. Für diese mechanismenübergreifende Studie wurden aufgrund ihrer allgemein begünstigenden Eigenschaften in Formulierungen und ihrer strukturellen Vielfalt die Tensidklassen der Sorbitanester (Span), Polysorbate (Tween) und Oleylalkoholpolyglykolether (Genapol O) verwendet. Die Absenkung der Grenzflächenspannung ist eine der wesentlichen physikalisch-chemischen Eigenschaften von Tensiden. Die dynamische Oberflächenspannung (DST) wurde untersucht, um das Verhalten beim Absenken der Oberflächenspannung einzuschätzen, welches die Tropfenbildung und die Retentionseigenschaften beeinflusst. Die DST ist zeitabhängig und das kritische Zeitfenster, in dem ein Tropfen auf die Pflanzenoberfläche auftrifft, beläuft sich auf ca. 100 ms. Innerhalb dieses Zeitrahmens konnte keines von den ausgewählten Tensiden die Oberflächenspannung hinreichend herabsetzen (vgl. Kapitel I). Bei ca. 100 ms wies Tween 20 die niedrigsten DST-Werte auf. Bei vollständiger Absättigung der Tropfen-Luft-Grenzfläche durch Tensidmonomere kann eine statische Oberflächenspannung (STeq) bestimmt werden. Diese physikalische Größe kann benutzt werden, um Spreitungs- und „run-off“- Effekte abzuschätzen. Der Großteil der betrachteten Tenside zeigte ähnliche STeq-Ergebnisse zwischen 30 und 45 mN m- 1. Somit waren alle Tenside in der Lage, die Oberflächenspannung von Wasser (72 mN m- 1) beträchtlich abzusenken. Der Einfluss von Tensiden auf den Benetzungsprozess wurde sowohl mit Hilfe von zeitabhängigen, statischen Kontaktwinkelmessungen auf verschiedenen Oberflächen, als auch nach der Wasserverdunstung auf Basis der Spreitungsfläche der Tropfen auf Triticum aestivum Blättern analysiert. Dabei zeigte die Klasse der Spans, besonders Span 20, ein besseres Benetzungsverhalten als die Klasse der Tweens. Um die Erkenntnisse aus dem Labor auf die Sprayapplikation auf dem Feld zu übertragen, wurden Retention und Blattbedeckung quantitativ auf Weizenoberflächen mit Hilfe eines „tracksprayers“ bestimmt. Da der Retention ein sehr schnell ablaufender, dynamischer Prozess zugrunde liegt, korreliert sie nicht mit der statischen, sondern mit der dynamischen Oberflächenspannung. Die Beziehung zwischen DST, bei ca. 100 ms und den „tracksprayer“- Ergebnissen zeigte eine Retentionszunahme bei abnehmender DST. Dabei konnte keine weitere Retentionsverbesserung bei DST-Werten unterhalb von ca. 60 mN m- 1 erzielt werden. Nachdem der Tropfen auf der Blattoberfläche gelandet ist, verdunstet Wasser unter Feldbedingungen aus dem Sprühtropfen innerhalb weniger Sekunden bis Minuten. Da das Auskristallisieren der Aktivsubstanz zwingend vermieden werden muss, werden sog. „humectants“ (dt. Feuchthaltemittel) als Tankmix-Adjuvantien eingesetzt, um die Aktivsubstanz in Lösung zu halten. Die Fähigkeit von Tensiden, Wasser aus der umgebenden Atmosphäre zu binden, wurde mit Hilfe von Wassersorptionsisothermen umfassend analysiert (vgl. Kapitel II). Diese Isothermen zeigten einen exponentiellen Verlauf mit einem steilen Anstieg der Wassersorption, beginnend ab ca. 60 bis 70% RH (relative Luftfeuchte). Dabei zeigten Spans eine geringere Wassersorption als die polyethoxylierten Tenside (Tweens und Genapol O). Die Beziehung zwischen dem Wassersorptionsverhalten und der molekularen Struktur der Tenside wurde als sog. „humectant Aktivität“ betrachtet. Speziell für die Klasse der Genapol O Tenside, wurde mit zunehmenden Ethylenoxidgehalt (EO) eine Zunahme der „humectant Aktivität“ nachgewiesen. Es konnte jedoch auch gezeigt werden, dass die Wassersorption über alle Klassen der hier ausgewählten Tenside eher mit dem „hydrophilic-lipophilic-balance“- Wert (HLB) als mit dem EO-Gehalt korreliert. Die Kutikula ist eine Membran, die alle oberirdischen Pflanzenorgane bedeckt. Damit stellt sie die wichtigste transportlimitierende Barriere für die Aufnahme von Pflanzenschutzmittelwirkstoffen dar. Um die Wirkung von Adjuvantien auf die Penetration des lipophilen Herbizids Pinoxaden (PXD) zu bestimmen, wurden in vitro Penetrationsexperimente durch eine astomatäre Modellkutikula durchgeführt (vgl. Kapitel III). Um den Einfluss verschiedener Wirkmechanismen, wie z.B. die der „humectant“- Eigenschaft zu verstehen, wurden diese Versuche unter drei verschiedenen Luftfeuchtebedingungen durchgeführt. Hierbei konnte kein klarer Zusammenhang zwischen der relativen Luftfeuchte und der PXD-Penetration nachgewiesen werden. Eine Ursache dafür könnte sein, dass sich Luftfeuchteeffekte eher auf hydrophile als auf lipophile Stoffe auswirken. Vielmehr wurde deutlich, dass hier eine komplexe Kombination aus verschiedenen Wirkmechanismen, wie z.B. Spreitungs-, „humectant“- und Weichmachereffekte, zum Tragen kommt. Um den Einfluss von Adjuvantien auf die in vivo Wirkung von PXD zu analysieren, wurden Gewächshausstudien mit fünf verschiedenen Ungräsern durchgeführt (vgl. Kapitel III). Da die Applikation von Pflanzenschutzwirkstoffen auch deren nachfolgende Wirkung auf lebende Pflanzen, wie z.B. Translokationsprozesse in planta und speziesspezifische physiologische Effekte beinhaltet, kann diese Untersuchung helfen, die Situation auf dem Feld besser zu simulieren. Durch die sowohl verschiedenen Pflanzenspezies als auch PXD-Konzentrationen variierte die absolute Schädigung der Ungräser stark. Dennoch kam es zur gleichen Reihenfolge der Auswirkung der Adjuvantien wie in den in vitro Kutikula-Penetrationsversuchen: Tween 20 > Tween 80 > Span 20 ≥ Span 80. Somit konnte in der vorliegenden Arbeit zum ersten Mal gezeigt werden, dass Erkenntnisse aus Laborversuchen, die die Wirkmechanismen von Adjuvantien betreffen, erfolgreich auf die Sprayapplikation auf Pflanzen übertragen werden können. Um eine systematische Herleitung der Wirkmechanismen von Adjuvantien abschließend zusammenzufassen, vergleichen und bewerten zu können, wurde dies mit Hilfe von Netzdiagrammen grafisch dargestellt (vgl. Zusammenfassende Diskussion und Ausblick). Dabei konnten Zusammenhänge zwischen strukturellen Ähnlichkeiten von Adjuvantien und deren Wirkmechanismen gefunden werden. Tween 20 und Tween 80 beispielsweise deckten ein sehr breites Spektrum an Mechanismen ab, zeigten dabei aber keinen herausragenden Wirkmechanismus einen bestimmten Prozess betreffend. Im Gegensatz dazu wiesen die nicht-ethoxylierten Span 20 und Span 80 hauptsächlich nur den oberflächenaktiven Mechanismus auf. Fast alle Adjuvantien, die in dieser Arbeit analysiert wurden, stellen komplexe polydisperse Mischungen dar, denen eine komplizierte Verteilung von EO-Gruppen und aliphatischen Ketten zugrunde liegt. Aus den Ergebnissen der vorliegenden Arbeit kann gemutmaßt werden, dass Adjuvantien mit einer eher breiten EO-Verteilung ein breiteres Anwendungsspektrum bieten können als Adjuvantien mit einer kleineren Verteilung. Es lässt sich vermuten, dass durch das Vorhandensein einer enormen Vielzahl einzelner Moleküle, die jeweils einen individuellen spezifischen physikalisch-chemischen Charakter aufweisen, ein großes Spektrum von Eigenschaften bezüglich der Sprayapplikation abgedeckt wird. KW - Adjuvans KW - Pflanzenschutzmittel KW - Adjuvant KW - Plant Protection KW - Kutikula KW - Plant Protection Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-138159 ER - TY - JOUR A1 - Joensuu, Johanna A1 - Altimir, Nuria A1 - Hakola, Hannele A1 - Rostás, Michael A1 - Raivonen, Maarit A1 - Vestenius, Mika A1 - Aaltonen, Hermanni A1 - Riederer, Markus A1 - Bäck, Jaana T1 - Role of needle surface waxes in dynamic exchange of mono- and sesquiterpenes JF - Atmospheric Chemistry and Physics N2 - Biogenic volatile organic compounds (BVOCs) produced by plants have a major role in atmospheric chemistry. The different physicochemical properties of BVOCs affect their transport within and out of the plant as well as their reactions along the way. Some of these compounds may accumulate in or on the waxy surface layer of conifer needles and participate in chemical reactions on or near the foliage surface. The aim of this work was to determine whether terpenes, a key category of BVOCs produced by trees, can be found on the epicuticles of Scots pine (Pinus sylvestris L.) and, if so, how they compare with the terpenes found in shoot emissions of the same tree. We measured shoot-level emissions of pine seedlings at a remote outdoor location in central Finland and subsequently analysed the needle surface waxes for the same compounds. Both emissions and wax extracts were clearly dominated by monoterpenes, but the proportion of sesquiterpenes was higher in the wax extracts. There were also differences in the terpene spectra of the emissions and the wax extracts. The results, therefore, support the existence of BVOC associated to the epicuticular waxes. We briefly discuss the different pathways for terpenes to reach the needle surfaces and the implications for air chemistry. KW - Biogenic KW - volatile KW - organic KW - compounds Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-198547 VL - 16 ER - TY - JOUR A1 - Böhm, Jennifer A1 - Scherzer, Sönke A1 - Krol, Elzbieta A1 - Kreuzer, Ines A1 - von Meyer, Katharina A1 - Lorey, Christian A1 - Mueller, Thomas D. A1 - Shabala, Lana A1 - Monte, Isabel A1 - Solano, Roberto A1 - Al-Rasheid, Khaled A. S. A1 - Rennenberg, Heinz A1 - Shabala, Sergey A1 - Neher, Erwin A1 - Hedrich, Rainer T1 - The Venus flytrap Dionaea muscipula counts prey-induced action potentials to induce sodium uptake JF - Current Biology N2 - Carnivorous plants, such as the Venus flytrap (Dionaea muscipula), depend on an animal diet when grown in nutrient-poor soils. When an insect visits the trap and tilts the mechanosensors on the inner surface, action potentials (APs) are fired. After a moving object elicits two APs, the trap snaps shut, encaging the victim. Panicking preys repeatedly touch the trigger hairs over the subsequent hours, leading to a hermetically closed trap, which via the gland-based endocrine system is flooded by a prey-decomposing acidic enzyme cocktail. Here, we asked the question as to how many times trigger hairs have to be stimulated (e.g., now many APs are required) for the flytrap to recognize an encaged object as potential food, thus making it worthwhile activating the glands. By applying a series of trigger-hair stimulations, we found that the touch hormone jasmonic acid (JA) signaling pathway is activated after the second stimulus, while more than three APs are required to trigger an expression of genes encoding prey-degrading hydrolases, and that this expression is proportional to the number of mechanical stimulations. A decomposing animal contains a sodium load, and we have found that these sodium ions enter the capture organ via glands. We identified a flytrap sodium channel DmHKT1 as responsible for this sodium acquisition, with the number of transcripts expressed being dependent on the number of mechano-electric stimulations. Hence, the number of APs a victim triggers while trying to break out of the trap identifies the moving prey as a struggling Na\(^+\)-rich animal and nutrition for the plant. KW - jasmonic acid biosynthesis KW - gene expression KW - signal transduction KW - transporters KW - Arabidopsis Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-190870 VL - 26 IS - 3 ER - TY - JOUR A1 - Nukarinen, Ella A1 - Nägele, Thomas A1 - Pedrotti, Lorenzo A1 - Wurzinger, Bernhard A1 - Mair, Andrea A1 - Landgraf, Ramona A1 - Börnke, Frederik A1 - Hanson, Johannes A1 - Teige, Markus A1 - Baena-Gonzalez, Elena A1 - Dröge-Laser, Wolfgang A1 - Weckwerth, Wolfram T1 - Quantitative phosphoproteomics reveals the role of the AMPK plant ortholog SnRK1 as a metabolic master regulator under energy deprivation JF - Scientific Reports N2 - Since years, research on SnRK1, the major cellular energy sensor in plants, has tried to define its role in energy signalling. However, these attempts were notoriously hampered by the lethality of a complete knockout of SnRK1. Therefore, we generated an inducible amiRNA::SnRK1α2 in a snrk1α1 knock out background (snrk1α1/α2) to abolish SnRK1 activity to understand major systemic functions of SnRK1 signalling under energy deprivation triggered by extended night treatment. We analysed the in vivo phosphoproteome, proteome and metabolome and found that activation of SnRK1 is essential for repression of high energy demanding cell processes such as protein synthesis. The most abundant effect was the constitutively high phosphorylation of ribosomal protein S6 (RPS6) in the snrk1α1/α2 mutant. RPS6 is a major target of TOR signalling and its phosphorylation correlates with translation. Further evidence for an antagonistic SnRK1 and TOR crosstalk comparable to the animal system was demonstrated by the in vivo interaction of SnRK1α1 and RAPTOR1B in the cytosol and by phosphorylation of RAPTOR1B by SnRK1α1 in kinase assays. Moreover, changed levels of phosphorylation states of several chloroplastic proteins in the snrk1α1/α2 mutant indicated an unexpected link to regulation of photosynthesis, the main energy source in plants. KW - phosphoproteomics KW - SnRK1 KW - energy deprivation KW - plants Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-167638 VL - 6 IS - 31697 ER - TY - JOUR A1 - Bhavsar, Shefalee K. A1 - Singh, Yogesh A1 - Sharma, Piyush A1 - Khairnar, Vishal A1 - Hosseinzadeh, Zohreh A1 - Zhang, Shaqiu A1 - Palmada, Monica A1 - Sabolic, Ivan A1 - Koepsell, Hermann A1 - Lang, Karl S. A1 - Lang, Philipp A. A1 - Lang, Florian T1 - Expression of JAK3 Sensitive Na\(^+\) Coupled Glucose Carrier SGLT1 in Activated Cytotoxic T Lymphocytes JF - Cellular Physiology and Biochemistry N2 - Background: Similar to tumor cells, activated T-lymphocytes generate ATP mainly by glycolytic degradation of glucose. Lymphocyte glucose uptake involves non-concentrative glucose carriers of the GLUT family. In contrast to GLUT isoforms, Na+-coupled glucose-carrier SGLT1 accumulates glucose against glucose gradients and is effective at low extracellular glucose concentrations. The present study explored expression and regulation of SGLT1 in activated murine splenic cytotoxic T cells (CTLs) and human Jurkat T cells. Methods: FACS analysis, immunofluorescence, confocal microscopy, chemiluminescence and Western blotting were employed to estimate SGLT1 expression, function and regulation in lymphocytes, as well as dual electrode voltage clamp in SGLT1 ± JAK3 expressing Xenopus oocytes to quantify the effect of janus kinase3 (JAK3) on SGLT1 function. Results: SGLT1 is expressed in murine CTLs and also in human Jurkat T cells. 2-(N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino)-2-deoxyglucose uptake was significantly decreased by SGLT1-blocker phloridzin (0.2 mM) and by pharmacological inhibition of JAK3 with WHI-P131 (156 µM), WHI-P154 (11.2 µM) and JAK3 inhibitor VI (0.5 µM). Electrogenic glucose transport (Iglucose) in Xenopus oocytes expressing human SGLT1 was increased by additional expression of human wild type JAK3, active A568VJAK3 but not inactive K851AJAK3. Coexpression of JAK3 enhanced the maximal transport rate without significantly modifying affinity of the carrier. Iglucose in SGLT1+JAK3 expressing oocytes was significantly decreased by WHI-P154 (11.2 µM). JAK3 increased the SGLT1 protein abundance in the cell membrane. Inhibition of carrier insertion by brefeldin A (5 µM) in SGLT1+JAK3 expressing oocytes resulted in a decline of Iglucose, which was similar in presence and absence of JAK3. Conclusions: SGLT1 is expressed in murine cytotoxic T cells and human Jurkat T cells and significantly contributes to glucose uptake in those cells post activation. JAK3 up-regulates SGLT1 activity by increasing the carrier protein abundance in the cell membrane, an effect enforcing cellular glucose uptake into activated lymphocytes and thus contributing to the immune response. KW - tumor cell KW - Cytotoxic T lymphocytes KW - Glucose uptake KW - Jurkat T cells KW - Energy depletion KW - Janus kinase Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-164900 VL - 39 IS - 3 ER - TY - JOUR A1 - Boschert, V. A1 - Frisch, C. A1 - Back, J. W. A1 - van Pee,, K. A1 - Weidauer, S. E. A1 - Muth, E.-M. A1 - Schmieder, P. A1 - Beerbaum, M. A1 - Knappik, A. A1 - Timmerman, P. A1 - Mueller, T. D. T1 - The sclerostin-neutralizing antibody AbD09097 recognizes an epitope adjacent to sclerostin's binding site for the Wnt co-receptor LRP6 JF - Open Biology N2 - The glycoprotein sclerostin has been identified as a negative regulator of bone growth. It exerts its function by interacting with the Wnt co-receptor LRP5/6, blocks the binding of Wnt factors and thereby inhibits Wnt signalling. Neutralizing anti-sclerostin antibodies are able to restore Wnt activity and enhance bone growth thereby presenting a new osteoanabolic therapy approach for diseases such as osteoporosis. We have generated various Fab antibodies against human and murine sclerostin using a phage display set-up. Biochemical analyses have identified one Fab developed against murine sclerostin, AbD09097 that efficiently neutralizes sclerostin's Wnt inhibitory activity. In vitro interaction analysis using sclerostin variants revealed that this neutralizing Fab binds to sclerostin's flexible second loop, which has been shown to harbour the LRP5/6 binding motif. Affinity maturation was then applied to AbD09097, providing a set of improved neutralizing Fab antibodies which particularly bind human sclerostin with enhanced affinity. Determining the crystal structure of AbD09097 provides first insights into how this antibody might recognize and neutralize sclerostin. Together with the structure–function relationship derived from affinity maturation these new data will foster the rational design of new and highly efficient anti-sclerostin antibodies for the therapy of bone loss diseases such as osteoporosis. KW - phage display KW - Wnt signalling KW - sclerostin KW - neutralizing antibody KW - osteoporosis Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-177925 VL - 6 ER - TY - JOUR A1 - Böhm, J. A1 - Scherzer, S. A1 - Shabala, S. A1 - Krol, E. A1 - Neher, E. A1 - Mueller, T. D. A1 - Hedrich, R. T1 - Venus flytrap HKT1-type channel provides for prey sodium uptake into carnivorous plant without conflicting with electrical excitability JF - Molecular Plant N2 - The animal diet of the carnivorous Venus flytrap, Dionaea muscipula, contains a sodium load that enters the capture organ via an HKT1-type sodium channel, expressed in special epithelia cells on the inner trap lobe surface. DmHKT1 expression and sodium uptake activity is induced upon prey contact. Here, we analyzed the HKT1 properties required for prey sodium osmolyte management of carnivorous Dionaea. Analyses were based on homology modeling, generation of model-derived point mutants, and their functional testing in Xenopus oocytes. We showed that the wild-type HKT1 and its Na\(^+\)- and K\(^+\)-permeable mutants function as ion channels rather than K\(^+\) transporters driven by proton or sodium gradients. These structural and biophysical features of a high-capacity, Na\(^+\)-selective ion channel enable Dionaea glands to manage prey-derived sodium loads without confounding the action potential-based information management of the flytrap. KW - sodium channel KW - HKT1 KW - Dionaea muscipula KW - action potential KW - glands KW - sodium uptake Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-189803 VL - 9 IS - 3 ER - TY - JOUR A1 - Klughammer, Christof A1 - Schreiber, Ulrich T1 - Deconvolution of ferredoxin, plastocyanin, and P700 transmittance changes in intact leaves with a new type of kinetic LED array spectrophotometer JF - Photosynthesis Research N2 - A newly developed compact measuring system for assessment of transmittance changes in the near-infrared spectral region is described; it allows deconvolution of redox changes due to ferredoxin (Fd), P700, and plastocyanin (PC) in intact leaves. In addition, it can also simultaneously measure chlorophyll fluorescence. The major opto-electronic components as well as the principles of data acquisition and signal deconvolution are outlined. Four original pulse-modulated dual-wavelength difference signals are measured (785-840 nm, 810-870 nm, 870-970 nm, and 795-970 nm). Deconvolution is based on specific spectral information presented graphically in the form of 'Differential Model Plots' (DMP) of Fd, P700, and PC that are derived empirically from selective changes of these three components under appropriately chosen physiological conditions. Whereas information on maximal changes of Fd is obtained upon illumination after dark-acclimation, maximal changes of P700 and PC can be readily induced by saturating light pulses in the presence of far-red light. Using the information of DMP and maximal changes, the new measuring system enables on-line deconvolution of Fd, P700, and PC. The performance of the new device is demonstrated by some examples of practical applications, including fast measurements of flash relaxation kinetics and of the Fd, P700, and PC changes paralleling the polyphasic fluorescence rise upon application of a 300-ms pulse of saturating light. KW - Chlorophyll fluorescence KW - Cyclic electron transport KW - FeS proteins KW - Flash relaxation kinetics KW - Photosystem I KW - Polyphasic fluorescence rise KW - Thioredoxin Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-189050 VL - 128 IS - 2 ER - TY - JOUR A1 - Cicova, Zdenka A1 - Dejung, Mario A1 - Skalicky, Tomas A1 - Eisenhuth, Nicole A1 - Hanselmann, Steffen A1 - Morriswood, Brooke A1 - Figueiredo, Luisa M. A1 - Butter, Falk A1 - Janzen, Christian J. T1 - Two flagellar BAR domain proteins in Trypanosoma brucei with stage-specific regulation JF - Scientific Reports N2 - Trypanosomes are masters of adaptation to different host environments during their complex life cycle. Large-scale proteomic approaches provide information on changes at the cellular level, and in a systematic way. However, detailed work on single components is necessary to understand the adaptation mechanisms on a molecular level. Here, we have performed a detailed characterization of a bloodstream form (BSF) stage-specific putative flagellar host adaptation factor Tb927.11.2400, identified previously in a SILAC-based comparative proteome study. Tb927.11.2400 shares 38% amino acid identity with TbFlabarin (Tb927.11.2410), a procyclic form (PCF) stage-specific flagellar BAR domain protein. We named Tb927.11.2400 TbFlabarin-like (TbFlabarinL), and demonstrate that it originates from a gene duplication event, which occurred in the African trypanosomes. TbFlabarinL is not essential for the growth of the parasites under cell culture conditions and it is dispensable for developmental differentiation from BSF to the PCF in vitro. We generated TbFlabarinL-specific antibodies, and showed that it localizes in the flagellum. Co-immunoprecipitation experiments together with a biochemical cell fractionation suggest a dual association of TbFlabarinL with the flagellar membrane and the components of the paraflagellar rod. KW - parasite biology KW - protein translocation KW - Trypanosoma brucei Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-181021 VL - 6 ER - TY - JOUR A1 - Jakobson, Liina A1 - Vaahtera, Lauri A1 - Tõldsepp, Kadri A1 - Nuhkat, Maris A1 - Wang, Cun A1 - Wang, Yuh-Shuh A1 - Hõrak, Hanna A1 - Valk, Ervin A1 - Pechter, Priit A1 - Sindarovska, Yana A1 - Tang, Jing A1 - Xiao, Chuanlei A1 - Xu, Yang A1 - Talas, Ulvi Gerst A1 - García-Sosa, Alfonso T. A1 - Kangasjärvi, Saijaliisa A1 - Maran, Uko A1 - Remm, Maido A1 - Roelfsema, M. Rob G. A1 - Hu, Honghong A1 - Kangasjärvi, Jaakko A1 - Loog, Mart A1 - Schroeder, Julian I. A1 - Kollist, Hannes A1 - Brosché, Mikael T1 - Natural Variation in Arabidopsis Cvi-0 Accession Reveals an Important Role of MPK12 in Guard Cell CO\(_{2}\) Signaling JF - PLoS Biology N2 - Plant gas exchange is regulated by guard cells that form stomatal pores. Stomatal adjustments are crucial for plant survival; they regulate uptake of CO\(_{2}\) for photosynthesis, loss of water, and entrance of air pollutants such as ozone. We mapped ozone hypersensitivity, more open stomata, and stomatal CO\(_{2}\)-insensitivity phenotypes of the Arabidopsis thaliana accession Cvi-0 to a single amino acid substitution in MITOGEN-ACTIVATED PROTEIN (MAP) KINASE 12 (MPK12). In parallel, we showed that stomatal CO\(_{2}\)-insensitivity phenotypes of a mutant cis (CO\(_{2}\)-insensitive) were caused by a deletion of MPK12. Lack of MPK12 impaired bicarbonate-induced activation of S-type anion channels. We demonstrated that MPK12 interacted with the protein kinase HIGH LEAF TEMPERATURE 1 (HT1)—a central node in guard cell CO\(_{2}\) signaling—and that MPK12 functions as an inhibitor of HT1. These data provide a new function for plant MPKs as protein kinase inhibitors and suggest a mechanism through which guard cell CO\(_{2}\) signaling controls plant water management. KW - MPK12 KW - CO\(_{2}\) signaling KW - Arabidopsis thaliana KW - Cvi-0 Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-166657 VL - 14 IS - 12 ER - TY - JOUR A1 - Shepard, Blythe D. A1 - Cheval, Lydie A1 - Peterlin, Zita A1 - Firestein, Stuart A1 - Koepsell, Hermann A1 - Doucet, Alain A1 - Pluznick, Jennifer L. T1 - A Renal Olfactory Receptor Aids in Kidney Glucose Handling JF - Scientific Reports N2 - Olfactory receptors (ORs) are G protein-coupled receptors which serve important sensory functions beyond their role as odorant detectors in the olfactory epithelium. Here we describe a novel role for one of these ORs, Olfr1393, as a regulator of renal glucose handling. Olfr1393 is specifically expressed in the kidney proximal tubule, which is the site of renal glucose reabsorption. Olfr1393 knockout mice exhibit urinary glucose wasting and improved glucose tolerance, despite euglycemia and normal insulin levels. Consistent with this phenotype, Olfr1393 knockout mice have a significant decrease in luminal expression of Sglt1, a key renal glucose transporter, uncovering a novel regulatory pathway involving Olfr1393 and Sglt1. In addition, by utilizing a large scale screen of over 1400 chemicals we reveal the ligand profile of Olfr1393 for the first time, offering new insight into potential pathways of physiological regulation for this novel signaling pathway. KW - olfactory receptor KW - Olfr1393 KW - kidney KW - glucose handling Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-167605 VL - 6 IS - 35215 ER -