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Portable dielectrophoresis for biology:ADEPT facilitates cell trapping,separation,and interactions

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Microsystems & Nanoengineering 2024年第2期10卷 193-205页

作者： Lourdes Albina Nirupa julius Dora Akgül Gowri Krishnan Fabian Falk Jan Korvink Vlad Badilita Department Institute of Microstructure TechnologyKarlsruhe Institute of TechnologyHermann-von-Helmholtz-Platz 1Eggenstein-Leopoldshafen76344Baden-WürttembergGermany

Dielectrophoresis is a powerful and well-established technique that allows label-free,non-invasive manipulation of cells and particles by leveraging their electrical *** practical implementation of the associated electronics and user interface in a biology laboratory,however,requires an engineering background,thus hindering the broader adoption of the *** order to address these challenges and to bridge the gap between biologists and the engineering skills required for the implementation of DEP platforms,we report here a custom-built,compact,universal electronic platform termed ADEPT(adaptable dielectrophoresis embedded platform tool)for use with a simple microfluidic chip containing six *** versatility of the open-source platform is ensured by a custom-developed graphical user interface that permits simple reconfiguration of the control signals to address a wide-range of specific applications:(i)precision positioning of the single bacterium/cell/particle in the micrometer range;(ii)viability-based separation by achieving a 94%efficiency in separating live and dead yeast;(iii)phenotype-based separation by achieving a 96%efficiency in separating yeast and Bacillus subtilis;(iv)cell–cell interactions by steering a phagocytosis process where a granulocyte engulfs *** RGB-S ***,the set of experiments and the platform form a complete basis for a wide range of possible applications addressing various biological questions exploiting the plug-and-play design and the intuitive GUI of ADEPT.

关键词： Together separation separating

Current Injection Provokes Rapid Expansion of the Guard Cell Cytosolic Volume and Triggers Ca^2＋ Signals

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Molecular Plant 2016年第3期9卷 471-480页

作者： Lena J. Voss Rainer Hedrich M. Rob G. Roelfsema Molecular Plant Physiology and Biophysics Julius-von-Sachs Institute for Biosciences Biocenter Werzburg University Julius-von-Sachs-Platz 2 97082 Werzburg Germany

High-resolution microscopy opens the door for detailed single-cell studies with fluorescent reporter dyes and proteins. We used a confocal spinning disc microscope to monitor fluorescent dyes and the fluorescent protein Venus in tobacco and Arabidopsis guard cells. Multi-barreled microelectrodes were used to inject dyes and apply voltage pulses, which provoke transient rises in the cytosolic Ca^2＋ level. Voltage pulses also caused changes in the distribution of Lucifer Yellow and Venus, which pointed to a reversible increase of guard cell cytosolic volume. The dynamic cytosolic volume changes turned out to be provoked by current injection of ions. A reduction of the clamp current, by blocking K^＋ uptake channels with Cs^＋, strongly suppressed the cytosolic volume changes. Cs^＋ not only inhibited the expansion of the cytosol, but also inhibited hyperpolarization-induced elevations of the cytosolic Ca^2＋ concentration. A complete loss of voltage-induced Ca^2＋ signals occurred when Ca^2＋-permeable plasma membrane channels were simultaneously blocked with La^3＋. This shows that two mechanisms cause hyperpolarization-induced elevation of the cytosolic Ca^2＋-concentration：（i） activation of voltage-dependent Ca^2＋-permeable channels, （ii） osmotically induced expansion of the cytosol, which leads to a release of Ca^2＋ from intracellular stores.

关键词： guard cell cytosolic Ca^2+ cytosolic volume voltage clamp current injection ion channel

Plant Sucrose Transporters from a Biophysical Point of View

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Molecular Plant 2011年第3期4卷 395-406页

作者： Dietmar Geiger julius-von-sachs institute Molecular Plant Physiology and Biophysics University W6rzburg Julius-von-Sachs Platz 2 D-97082 W~rzburg Germany

The majority of higher plants use sucrose as their main mobile carbohydrate. Proton-driven sucrose trans- porters play a crucial role in cell-to-cell and long-distance distribution of sucrose throughout the plant. A very negative plant membrane potential and the ability of sucrose transporters to accumulate sucrose concentrations of more than 1 M indicate that plants evolved transporters with unique structural and functional features. The knowledge about the trans- port mechanism and structural/functional domains of these the current knowledge about the biophysical properties of nano-machines is, however, still fragmentary. In this review, plant sucrose transporters is summarized and discussed.

关键词： Biophysics electrophysiology transport processes/kinetics phloem physiology phloem unloading sucrose transport.

Establishment of a Photoautotrophic Cell Suspension Culture of Arabidopsis thaliana for Photosynthetic, Metabolic, and Signaling Studies

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Molecular Plant 2012年第2期5卷 524-527页

作者： Christine Hampp Andreas Richter Sonia Osorio Günther Zellnig Alok Krishna Sinha Alexandra Jammer Alisdair R. Fernie Bernhard Grimm Thomas Roitsch julius-von-sachs-institut fuer biowissenschaften UniversitaetWuerzburgJulius-von-Sachs-Platz 297082 WuerzburgGermany institute of Biology/Plant Physiology Humboldt UniversityPhilippstr.13Building 1210115 Berlin Max-Planck institute of Molecular Plant Physiology Am Mühlenberg 114476 Potsdam-GolmGermany institut fuer Pflanzenwissenschaften Schubertstr.51A-8010 GrazAustria National institute of Plant Genome Research PB No.10531Aruna Asaf Ali RoadNew Delhi–110067India

Dear Editor, Plant cell suspension cultures have been used as model systems to circumvent the problems associated with the analyses of a multi-factorial plant that is composed of multiple tissue and cell types exposed to diverse signals. A number of plant suspension cultures have proven to be valuable to study various topics including defense response, secondary metabolite formation, ion transport, gene regulation, and signal duction （Roitsch and Sinha, 2002 and references therein）. However, most cultures reported to date, including the cultures from model species such as Arabidopsis （Christie and Jenkins,

关键词： Photosynthetic Metabolic Signaling Studies

Post-Translational Derepression of Invertase Activity in Source Leaves via Down-Regulation of Invertase Inhibitor Expression Is Part of the Plant Defense Response

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Molecular Plant 2010年第6期3卷 1037-1048页

作者： Katharina B. Bonfig Andrea Gabler Uwe K. Simon Nora Luschin-Ebengreuth Martina Hatz Susanne Berger Naseem Muhammad Jurgen Zeier Alok K. Sinha Thomas Roitsch julius-von-sachs-institut fuer biowissenschaften Lehrstuhl for Pharmazeutische Biologie Universitaet Wuerzburg Julius-von-Sachs-Platz 2 97082 Wuerzburg Germany institute of Plant Sciences Department of Plant Physiology University of Graz 8010 Graz Austria Zentrum for rnedizinische Grundlagenforschung (ZMF) Medizinische Universitat Graz Stiftingtalstraβe 24 A-8010 Graz Department of Biology Plant Biology Section University of Fribourg Route Albert Gockel 3 CH-1700 Fribourg Switzerland National institute for Plant Genome Research Aruna Asaf Ali Road New Delhi 110067 India

There is increasing evidence that pathogens do not only elicit direct defense responses, but also cause pronounced changes in primary carbohydrate metabolism. Cell-wall-bound invertases belong to the key regulators of carbohydrate partitioning and source-sink relations. Whereas studies have focused so far only on the transcriptional induction of invertase genes in response to pathogen infection, the role of post-translational regulation of invertase activity has been neglected and was the focus of the present study. Expression analyses revealed that the high mRNA level of one out of three proteinaceous invertase inhibitors in source leaves of Arabidopsis thaliana is strongly repressed upon infection by a virulent strain of Pseudomonas syringae pv. tomato DC3000. This repression is paralleled by a decrease in invertase inhibitor activity. The physiological role of this regulatory mechanism is revealed by the finding that in situ invertase activity was detectable only upon infection by P. syringae. In contrast, a high invertase activity could be measured in vitro in crude and cell wall extracts prepared from both infected and non-infected leaves. The discrepancy between the in situ and in vitro invertase activity of control leaves and the high in situ invertase activity in infected leaves can be explained by the pathogen-dependent repression of invertase inhibitor expression and a concomitant reduction in invertase inhibitor activity. The functional importance of the release of invertase from post-translational inhibition for the defense response was substantiated by the application of the competitive chemical invertase inhibitor acarbose. Posttranslational inhibition of extracellular invertase activity by infiltration of acarbose in leaves was shown to increase the susceptibility to P. syringae. The impact of invertase inhibition on spatial and temporal dynamics of the repression of photosynthesis and promotion of bacterial growth during pathogen infection supports a

关键词： Acarbose Arabidopsis defense responses invertase inhibitor protein invertase plant-microbe interactions Pseudomonas syringae.

Poplar Extrafloral Nectar Is Protected against Plant and Human Pathogenic Fungus

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Molecular Plant 2012年第5期5卷 1157-1159页

作者： María Escalante-Pérez Mario Jaborsky Jorg Reinders Oliver Kurzai Rainer Hedrich Peter Ache University Würzburg BiozentrumJulius-von-Sachs-Institut für BiowissenschaftenJulius-von-Sachs-Platz 2D-97082 WürzburgGermany University Regensburg Institute of Functional GenomicsJosef-Engert-Strasse 9D-93053 RegensburgGermany Friedrich-Schiller-University Jena Septomics Research CentreBeutenbergstr.11aD-07745 JenaGermany

Dear Editor, Plants secrete nectar to attract mutualistic animals, which predominantly function as pollinators, as in the case of flo- ral nectar, or defenders against herbivores, as in the case of extrafloral nectar （Nicolson et al., 2007）. Because nectars usu- ally represent aqueous solutions containing sugars and other nutrient metabolites （Baker and Baker, 1983）, they are sus- ceptible to infestation by microbial organisms, which can use the nectar-secreting tissues as entry sites to infect the plant. Nectar-secreting tissues thus require an efficient shield against pathogen infections. To date, our knowledge about the way that plants protect their nectar from microorganisms is rather limited. Several reports have focused on ＇defensive chemicals＇,

关键词： Poplar Plant Human Pathogenic Fungus

Lichen species dominance and the resulting photosynthetic behavior of Sonoran Desert soil crust types(Baja California,Mexico)

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Ecological Processes 2013年第1期2卷 64-72页

作者： Burkhard Büdel Mercedes Vivas Otto L Lange Plant Ecology and Systematics Biology DepartmentUniversity of KaiserslauternP.O.Box 3049D-67653KaiserslauternGermany Department of Plant Science Faculty of PharmacyUniversidad Complutense de Madrid Plaza Ramóny Cajal28040MadridSpain julius-von-sachs-institut für biowissenschaften University of WürzburgJulius-von-Sachs-Platz 3D-97082WürzburgGermany.

Introduction:Lichen dominated biological soil crusts(BSCs)occur over large areas in the Sonoran Desert of the southwestern USA and northwest *** Baja California BSCs show a distinct patchiness and several types can be *** chlorolichen-and two cyanolichen-dominated BSCs were *** hypothesize that patchiness and the resulting domination of certain functional lichen groups will result in patchiness of photosynthetic CO_(2)-uptake related to environmental factors as ***:Four different soil crust samples were placed in cuvettes and their CO_(2) exchange was recorded in an open system with an infrared gas *** blown over the BSCs had a controlled CO_(2) content of 350 *** cuvettes were operated in *** CO2 exchange was continually recorded throughout the ***:Besides the dominating chlorolichens Psora decipiens and Placidium squamulosum and the cyanolichens Peltula patellata and ***,several other lichen species and 12 cyanobacterial species were found in the biological soil crusts *** chlorolichen BSCs already gained positive net photosynthesis with high air humidity alone,while the cyanolichen types did not,but showed smaller CO_(2)-uptake depression after water *** specific net photosynthesis responses to mode of hydration and to crust water content seem to correlate with precipitation characteristics of their ***:Species specific photosynthetic performance related to activation of respiration and net photosynthesis as well as to crust water content help to explain niche occupation and species composition of *** functional types have to be considered when they have a patchy distribution.

关键词： Biological soil crust Lichens Cyanobacteria Photosy

Targeting of Vacuolar Membrane Localized Members of the TPK Channel Family

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Molecular Plant 2008年第6期1卷 938-949页

作者： Marcel Dunkel Andreas Latz Karin Schumacher Thomas Muller Dirk Becker Rainer Hedrich Molecular Plant Physiology and Biophysics Julius-von-Sachs-lnstitute University of W0rzburg Julius-von-Sachs-Platz 2 97082 Worzburg Germany Heidelberger institut fur Pflanzenwissenschaften (HIP) University of Heidelberg Im Neuenheimer Feld 230 69120 Heidelberg Germany (K.S.) Present address: Physiological Ecology of Plants University ot T(3bingen Aut der Morgenstelle 1 72016 Tubingen Germany

Four members of the tandem-pore potassium channel family of Arabidopsis thaliana （TPK1, 2, 3, and 5） reside in the vacuolar membrane, whereas TPK4 is a plasma membrane K^＋-channel. By constructing chimeras between TPK1 and TPK4, we attempted to identify channel domains involved in the trafficking process and found that the TPK1 cytoplasmic C-terminal domain （CT） is critical for the ERas well as Golgi-sorting steps. Following site-directed mutagenesis, we identified a diacidic motif （DLE） required for ER-export of TPK1. However, this diacidic motif in the C-terminus is not conserved among other members of the TPK family, and TPK3 sorting is independent of its CT. Moreover, the 14-3-3 binding site of TPK1, essential for channel activation, is not involved in channel sorting.

关键词： Vacuolar Membrane TPK Channel Family Arabidopsis thaliana

Multiple Calcium-Dependent Kinases Modulate ABA-Activated Guard Cell Anion Channels

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Molecular Plant 2012年第6期5卷 1409-1412页

作者： Sonke Scherzer Tobias Maierhofer Khaled A.S. Al-Rasheid Dietmar Geiger Rainer Hedrich University of Würzburg Julius-von-Sachs-InstituteMolecular Plant Physiology and BiophysicsJulius-von-Sachs Platz 2D-97082 WürzburgGermany King Saud University Zoology DepartmentCollege of SciencePO Box 2455Riyadh 11451Saudi Arabia

Dear Editor, The plant hormone abscisic acid （ABA） governs drought stress management in plants. ABA signal transduction appears to be rather short. When under water stress con- ditions, the ABA level rises above a certain threshold and the phytohormone binds to its cytosolic RCAR/PYR/PYL-type receptor （Levchenko et al,, 2005; Joshi-Saha et al., 2011）. Following receptor activation, protein phosphatases of the clade-A PP2C type are inactivated, allowing SnRK protein kinases to phosphorylate their targets, such as bZIP tran- scription factors （Fujii et al., 2009 and references therein）. In guard cells and oocytes, we could demonstrate that the same SnRK-PP2C pair OST1-ABI1 controls the opening of the slow anion channel SLACl （Geiger et al., 2009; Lee et al., 2009）. Besides this calcium-independent activation, SLAC1 is also activated by the calcium-dependent kinases CPK21 and 23, which can be inhibited by ABI1 （Geiger et al., 2010）.

关键词： SLAC1