Diese Produktion und der experimentellen Arbeit hier vorgestellte spiegeln die engagierten und enthusiastischen Hilfe von Reynaldo Pareja freundlicherweise von Lina Aguirre, Gilberto Córdoba, William Mera, Ximena Bonilla und Darío Viveros unterstützt. Wir danken auch John Miles und drei anonymen Gutachtern für Kommentare, die uns, besser zu den Video-und Manuskript beigetragen.

1. Pflanzen <ol><li> Einzel-Stecklinge aus reifen Pflanzen sind als experimentelle Einheiten verwendet. Die Stecklinge werden bis 10 cm geschnitten, um die Einheitlichkeit der Pflanzmaterial gewährleisten. </li><li> Um zu verhindern, Kontamination durch Pflanzenpathogene werden die Stecklinge in eine 3% ige Natriumhypochlorit-Lösung für 2 min gewaschen und dann thoughroughly mit Leitungswasser gespült. </li><li> Jeder Schnitt ist in ca. gepflanzt. 36 g sterilem Boden in einem zylindrischen PVC-Rohr (5,3 cm Außendurchmesser von 6,5 cm Höhe) am unteren Ende mit einem Styropor-Becher versiegelt und verschlossen mit einem PVC-Buchse. Das Schneiden wird an Stelle von einem Schaumstoff-Ring in die zentrale Öffnung der Büchse platziert statt. </li><li> Die Pflanzen werden gedüngt und bewässert wie notwendig, um ausreichende Bodenfeuchte zu erhalten. </li><li> Die Pflanzen werden für einen Monat, bevor sie von Insekten in Frage gestellt werden, so dass die Entwicklung von oberflächlichen Wurzeln, die als Futterplätze für das Root-Xylem-Fütterung spittlebug Nymphen dienen. </li><li> PVC Rohre mit Stecklinge sind für 8 d vor Befall weiter stimulieren das Wachstum der oberflächlichen Wurzeln, teilweise bereinigt um angeborene Unterschiede in root Architektur invertiert. Dieser Schritt erfordert eine künstliche Lichtquelle, die wir für 24 Stunden am Tag. Zur Vermeidung von Verwechslung entkommt Herbivorie mit Pflanzenfresser Widerstand, repliziert einzelne Pflanze mit wenigen oder keinen oberflächlichen Wurzeln nach dieser Umkehrung der Behandlung aus dem Experiment werden eliminiert. Diese Eliminierung sollte selten, nie, die zur Beseitigung der Genotyp die sie vertreten. </li></ol> 2. Insekten <ol><li> Adult spittlebugs sind aus dem Bereich gesammelt, identifiziert werden, um Arten und eingeführt, um die Eiablage Käfigen, wo sie Laub empfänglicher brachiariagrasses bereitgestellt werden, um sich ernähren. Die Weibchen legen ihre Eier im Boden in einer flachen abnehmbaren Tablett auf dem Boden der Käfige gebracht werden, enthalten. </li><li> Nach einigen Tagen wird der Boden in Wasser suspendiert und durch eine Reihe von Sieben (42, 60 und 150 mesh), um die Eier zu sammeln. Aussetzung der gesiebte Material in eine 30% ige Kochsalzlösung bewirkt, dass die reifen Eizellen zu schweben, und hinterließ unreife Eier und restliche organische Substanz. </li><li> Um zu verhindern, Verunreinigungen durch Insekten Krankheitserreger, sind Eier in eine 0,5% ige Natriumhypochlorit-Lösung für 5 min desinfiziert und dann mit destilliertem Wasser gespült. </li><li> Jeder Test-Anlage (experimentelle Einheit) befallen ist an der Bodenoberfläche mit sechs reife Eier. Nur reife Eier in der Nähe von dem Schlüpfen sind für parasitäre Erkrankungen ausgewählt. Rosa Markierungen im hinteren Teil, entsprechend der Insekten Bauch; und eine voll ausgebaut Operculum Sie können durch die Anwesenheit von zwei roten Punkte in ihrem vorderen Teil, entsprechend dem Insekt die Augen identifiziert werden. </li><li> Erfolgreiche Brut wird 4 d später bestätigte an welcher Stelle alle unhatched Ei von einem Neugeborenen spittlebug aus unserer Kolonie ersetzt wird. </li><li> Testpflanzen werden in einer randomisierten vollständigen Block-Design mit sechs Wiederholungen pro Genotyp angeordnet. </li></ol> 3. Auswertungen <ol><li> Das Experiment ist ca ausgewertet. 30 d nach dem Befall (genaue Zeiten variieren je nach Insektenart studiert). </li><li> Der Schaden wird auf 1 bis 5 visuellen Skala, wobei 1 entspricht keine sichtbaren Schäden und 5 entspricht einem abgestorbenen Pflanzenteilen (Abbildung 1) erzielt. Scoring-Anlage Schaden liefert eine Schätzung der Toleranz. </li></ol><img src="/files/ftp_upload/3047/3047fig1.jpg" alt="Abbildung 1" /> Abbildung 1. Damage-Skala zur Toleranz gegenüber spittlebug Herbivorie in Brachiaria spp. 1 = keine nachweisbaren Schaden, 2 = 0-25% nekrotische Laub, 3 = 25-50% nekrotische Blätter, 4 = 50-75% nekrotische Laub, 5 = 75-100% nekrotische Laub. <ol start="3"><li> Insect Überleben wird durch Zählen der Insekten zu erreichen entweder ihre endgültige Erscheinungsform oder erwachsenen Stadium (Abbildung 2) bewertet. Scoring für Insekten das Überleben ermöglicht eine Schätzung der Antibiose. </li></ol><img src="/files/ftp_upload/3047/3047fig2.jpg" alt="Abbildung 2" /> Abbildung 2. Spittlebug Entwicklung von der ersten Larvenstadium (links) bis zur Erwachsenenbildung (rechts). Nur Insekten Erreichen zumindest ihre letzten Larvenstadium (Pfeile) zum Zeitpunkt der Evaluierung werden als gezählt &quot;Überlebenden&quot;. 4. Repräsentative Ergebnisse Ergebnisse einer repräsentativen Test-Screening Brachiaria Hybriden zum Widerstand gegen die spittlebug Aeneolamia reducta sind in Abbildung 3 dargestellt. <img src="/files/ftp_upload/3047/3047fig3.jpg" alt="Abbildung 3" /> Abbildung 3. Ergebnisse von Screening Brachiaria Hybriden für die Resistenz gegen spittlebug Aeneolamia reducta. Wir betrachten Pflanzen resistent, wenn ihre Antwort auf Herbivorie fällt in der unteren Hälfte dieses Grundstück. Antibiose steigt von rechts nach links und Toleranz erhöht sich von oben nach unten. Die Pfeile zeigen an unserem beständig überprüft.

<ol>
	<li>Painter, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Insect resistance in crop plants. , (1951).</li><li>Kogan, M., Ortman, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Antixenosis-a+new+term+proposed+to+define+Painter's+'Nonpreference'+modality+of+resistance.">Antixenosis-a new term proposed to define Painter's 'Nonpreference' modality of resistance.</a> Bull. Entomol. Soc. Am. 24, 175-176 (1978).</li><li>Kennedy, G., Gould, F., Deponti, O., Stinner, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ecological,+agricultural,+genetic,+and+commercial+considerations+in+the+deployment+of+insect-resistant+germplasm.">Ecological, agricultural, genetic, and commercial considerations in the deployment of insect-resistant germplasm.</a> Environ. Entomol. 16, 327-338 (1987).</li><li>Holmann, F., Peck, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Economic+damage+of+grassland+spittlebugs+(Homoptera+Cercopidae)+in+Colombia:+a+first+approximation+of+impact+on+animal+production+in+Brachiaria+decumbens.">Economic damage of grassland spittlebugs (Homoptera Cercopidae) in Colombia: a first approximation of impact on animal production in Brachiaria decumbens.</a> Neotrop. Entomol. 31, 275-284 (2002).</li><li>Miles, J. W., Cardona, C., Sotelo, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Recurrent+selection+in+a+synthetic+brachiariagrass+population+improves+resistance+to+three+spittlebug+species.">Recurrent selection in a synthetic brachiariagrass population improves resistance to three spittlebug species.</a> Crop Sci. 46, 1088-1093 (2006).</li><li>Ferrufino, A., Lapointe, S. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Host+plant+resistance+in+Brachiaria+grasses+to+the+spittlebug+Zulia+colombiana.">Host plant resistance in Brachiaria grasses to the spittlebug Zulia colombiana.</a> Entomol. Exp. Appl. 51, 155-162 (1989).</li><li>Lapointe, S. L., Serrano, M. S., Arango, G. L., Sotelo, G., Cordoba, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Antibiosis+to+spittlebugs+(Homoptera:+Cercopidae)+in+accessions+of+Brachiaria+spp.">Antibiosis to spittlebugs (Homoptera: Cercopidae) in accessions of Brachiaria spp.</a> J. Econ. Entomol. 82, 1764-1766 (1992).</li><li>Cardona, C., Miles, J. W., Sotelo, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+improved+methodology+for+massive+screening+of+Brachiaria+spp.+genotypes+for+resistance+to+Aeneolamia+varia+(Homoptera:+Cercopidae).">An improved methodology for massive screening of Brachiaria spp. genotypes for resistance to Aeneolamia varia (Homoptera: Cercopidae).</a> J. Econ. Entomol. 92, 490-496 (1999).</li><li>Cardona, C., Fory, P., Sotelo, G., Pabon, A., Diaz, G., Miles, J. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Antibiosis+and+tolerance+to+five+species+of+spittlebug+(Homoptera:+Cercopidae)+in+Brachiaria+spp.:+implications+for+breeding+for+resistance.">Antibiosis and tolerance to five species of spittlebug (Homoptera: Cercopidae) in Brachiaria spp.: implications for breeding for resistance.</a> J. Econ. Entomol. 97, 635-645 (2004).</li><li>Smith, C., Khan, Z., Pathak, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Techniques for evaluating insect resistance in crop plants. , (1994).</li><li>Lapointe, S., Sotelo, G., Arango, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Improved+technique+for+rearing+spittlebugs+(Homoptera:+Cercopidae).">Improved technique for rearing spittlebugs (Homoptera: Cercopidae).</a> J. Econ. Entomol. 82, 1764-1766 (1989).</li><li>Lopez, F., Cardona, C., Miles, J. W., Sotelo, G., Montoya, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Screening+for+resistance+to+adult+spittlebugs+(Hemiptera:+Cercopidae)+in+Brachiaria+spp.:+methods+and+categories+of+resistance.">Screening for resistance to adult spittlebugs (Hemiptera: Cercopidae) in Brachiaria spp.: methods and categories of resistance.</a> J. Econ. Entomol. 102, 1309-1316 (2009).</li></ol>

Diskriminierende unter Pflanzenfresser Resistenzmechanismen beleuchten kann Pflanzenzüchtung Bemühungen 3. Widerstand auf starke Antibiose Basis könnten unter bestimmten Umständen zu schaffen Selektionsdruck für mehr aggressive Schädling Biotypen. Auf der anderen Seite, könnte Widerstand Toleranz erlauben Schädlingspopulationen zu erhöhen, bis schließlich Toleranz ist überwältigt. Zucht für dauerhafte Beständigkeit, daher erfordert eine sorgfältige Prüfung dessen, was Resistenzmechanismen würden die meisten Stabilität für eine bestimmte Pflanze / Pflanzenschutz-System verleihen [siehe Kennedy et al. (1987) für eine umfassende Diskussion zum Thema] 3. Dieses Video-Demonstration basiert auf mehreren früheren Studien entwickelt, um die relativen Beiträge der Antibiose und Toleranz zu spittlebug Widerstand in brachiariagrasses 6-9 schätzen. Im Gegensatz zu Choice-Tests oder Feldversuche, sicherzustellen, dass keine-Choice-Tests alle Pflanzen die gleichen Pflanzenfresser Druck, wodurch Steuerung für Differenzen aus Pflanzenfresser Verhalten (zB Host-Präferenz, Aggregation). Aus diesem Grund sind jedoch nicht-Choice-Tests ungeeignet, um Widerstand antixenosis beurteilen. Künstlich Aufzucht Insektenkolonien ist die bevorzugte Methode zu testen, Insekten-Resistenz-Screening-Assays 10 zu erhalten. Kolonien bieten eine zuverlässige und einheitliche Quelle der spittlebugs eines bekannten Alters für Experimente durchgeführt jeder Zeit des Jahres 11 sein. Es kann jedoch notwendig sein, regelmäßig infundiert wilden Individuen in der Kolonie, um sicherzustellen, dass die Kolonie nicht genetisch abweichen entsprechende Feld Bevölkerung 10. Um die Eignung dieser künstlich aufgezogenen Pflanzenfresser zu bewerten und zu überwachen mögliche Veränderungen in ihrer Aggressivität im Laufe der Zeit ist es wichtig, dass alle Vorführungen geeignete Kontrollen der bekannten Widerstand Ebenen umfassen. Mehrere Parameter müssen sorgfältig definiert werden, um einen geeigneten Widerstand Screening-Assay-Design. Ein paar wichtige Parameter, die wir als unsere Test-Design haben, gehören das Alter der Wirtspflanzen, der Art und dem Entwicklungsstadium der spittlebugs, der Befall und die Dauer der Pflanze-Insekt-Kontakt 8,9,12. Mehrere Runden des Experimentierens und Protokoll Verfeinerung erforderlich sein, um zu einer schnellen, kostengünstigen, zuverlässigen Test, der ausreichend prognostiziert Pflanzenfresser Widerstand im Bereich erreichen.

characterizing herbivore resistance mechanisms: spittlebugs on brachiaria spp. as an example

Antixenosis, Antibiose und Toleranz 1: Pflanzen können Pflanzenfresser Schäden, die durch drei große Mechanismen zu widerstehen. Antixenosis ist der Grad, zu dem die Anlage vermieden werden, wenn die Pflanzenfresser in der Lage ist, um andere Pflanzen 2 ist. Antibiose ist der Grad, zu dem die Anlage wirkt sich auf die Fitness der Pflanzenfresser ernähren sie 1. Toleranz ist das Ausmaß, in dem die Anlage standhalten können oder Beseitigung von Schäden durch die Pflanzenfresser verursacht, ohne dass die Pflanzenfresser das Wachstum und die Reproduktion 1. Die Haltbarkeit der Pflanzenfresser Widerstand in einer landwirtschaftlichen Einstellung hängt zu einem großen Teil auf den Resistenzmechanismus bei Pflanzen Züchtungsanstrengungen 3 begünstigt. Wir zeigen eine nicht-Choice-Experiment entwickelt, um die relativen Beiträge der Antibiose und Toleranz zu spittlebug Widerstand in Brachiaria spp schätzen. Mehrere Arten von afrikanischen Gräsern der Gattung Brachiaria sind wertvolle Futter und Weide-Pflanzen in der Neotropis, aber sie können stark von mehreren einheimischen Arten von spittlebugs (Hemiptera: Cercopidae) angefochten werden. 4 Um ihren Widerstand gegen spittlebugs zu beurteilen, werden Pflanzen vegetativ vermehrte durch Stecklinge und dürfen für ca. 1 Monat wachsen, so dass das Wachstum der oberflächlichen Wurzeln, auf denen spittlebugs ernähren kann. An diesem Punkt wird jeder Test-Anlage individuell mit sechs spittlebug Eier in der Nähe Schlüpfen in Frage gestellt. Parasitäre Erkrankungen dürfen für einen Monat vor dem Auswerten Anlage beschädigen und Insekten das Überleben Fortschritt. Scoring-Anlage Schaden liefert eine Schätzung der Toleranz, während Scoring Insekten das Überleben ermöglicht eine Schätzung der Antibiose. Dieses Protokoll hat unsere Pflanzenzüchtung Ziel erleichtert zu spittlebug Widerstand in kommerziellen brachiariagrases 5 zu verbessern.

Watch this Scientific Journal Video about Characterizing Herbivore Resistance Mechanisms: Spittlebugs on Brachiaria spp. as an Example at JoVE.com

Characterizing Herbivore Resistance Mechanisms: Spittlebugs on Brachiaria spp. as an Example

Dieses Video erklärt, Mechanismen der Wirtspflanze Resistenz gegen Insektenfraß und zeigt eine nicht-Choice-Test, dass die relativen Beiträge der Antibiose und Toleranz zu spittlebug Widerstand in den Schätzungen<em&gt; Brachiaria</em&gt; Spp.

Charakterisierung Herbivore Resistenzmechanismen: Spittlebugs auf Brachiaria Spp. als Beispiel

Plants can resist herbivore damage through three broad mechanisms: antixenosis, antibiosis and tolerance1. Antixenosis is the degree to which the plant is ...

characterizing-herbivore-resistance-mechanisms-spittlebugs-on

Nanyang Technological University

Research

JoVE Journal

Biology

Characterizing Herbivore Resistance Mechanisms: Spittlebugs on Brachiaria spp. as an Example

13.7K Aufrufe.  CIAT. Dieses Video erklärt, Mechanismen der Wirtspflanze Resistenz gegen Insektenfraß und zeigt eine nicht-Choice-Test, dass die relativen Beiträge der Antibiose und Toleranz zu spittlebug Widerstand in den Schätzungen Brachiaria Spp.

Serie: Characterizing Herbivore Resistance Mechanisms: Spittlebugs on Brachiaria spp. as an Example

Genetic Studies of Human DNA Repair Proteins Using Yeast as a Model System 

Understanding the roles of human DNA repair proteins in genetic pathways is a formidable challenge to many researchers. Genetic studies in mammalian systems have been limited due to the lack of readily available tools including defined mutant genetic cell lines, regulatory expression systems, and appropriate selectable markers. To circumvent these difficulties, model genetic systems in lower eukaryotes have become an attractive choice for the study of functionally conserved DNA repair proteins and pathways. We have developed a model yeast system to study the poorly defined genetic functions of the Werner syndrome helicase-nuclease (WRN) in nucleic acid metabolism. Cellular phenotypes associated with defined genetic mutant backgrounds can be investigated to clarify the cellular and molecular functions of WRN through its catalytic activities and protein interactions. The human WRN gene and associated variants, cloned into DNA plasmids for expression in yeast, can be placed under the control of a regulatory plasmid element. The expression construct can then be transformed into the appropriate yeast mutant background, and genetic function assayed by a variety of methodologies. Using this approach, we determined that WRN, like its related RecQ family members BLM and Sgs1, operates in a Top3-dependent pathway that is likely to be important for genomic stability. This is described in our recent publication [1] at <a href="http://www.impactaging.com">www.impactaging.com</a>. Detailed methods of specific assays for genetic complementation studies in yeast are provided in this paper.

Genetic Studies of Human DNA Repair Proteins Using Yeast as a Model System

Genetic studies in yeast can be employed to investigate the molecular and cellular functions of human genes in cellular DNA metabolism. Methods are described for the genetic characterization of the human WRN gene product defective in the premature aging disorder Werner syndrome in functionally conserved pathways using yeast as a tractable model system.

Genetic Studies of Human DNA-Reparatur-Proteinen unter Verwendung von Hefe als Modellsystem

Understanding the roles of human DNA repair proteins in genetic pathways is a formidable challenge to many researchers.  Genetic studies in mammalian ...

Forschung

Biologie

Herbivore-induced Blueberry Volatiles and Intra-plant Signaling

Herbivore-induced plant volatiles (HIPVs) are commonly emitted from plants after herbivore attack1,2. These HIPVs are mainly regulated by the defensive plant hormone jasmonic acid (JA) and its volatile derivative methyl jasmonate (MeJA)3,4,5. Over the past 3 decades researchers have documented that HIPVs can repel or attract herbivores, attract the natural enemies of herbivores, and in some cases they can induce or prime plant defenses prior to herbivore attack. In a recent paper6, I reported that feeding by gypsy moth caterpillars, exogenous MeJA application, and mechanical damage induce the emissions of volatiles from blueberry plants, albeit differently. In addition, blueberry branches respond to HIPVs emitted from neighboring branches of the same plant by increasing the levels of JA and resistance to herbivores (i.e., direct plant defenses), and by priming volatile emissions (i.e., indirect plant defenses). Similar findings have been reported recently for sagebrush7, poplar8, and lima beans9..
Here, I describe a push-pull method for collecting blueberry volatiles induced by herbivore (gypsy moth) feeding, exogenous MeJA application, and mechanical damage. The volatile collection unit consists of a 4 L volatile collection chamber, a 2-piece guillotine, an air delivery system that purifies incoming air, and a vacuum system connected to a trap filled with Super-Q adsorbent to collect volatiles5,6,10. Volatiles collected in Super-Q traps are eluted with dichloromethane and then separated and quantified using Gas Chromatography (GC). This volatile collection method was used n my study6 to investigate the volatile response of undamaged branches to exposure to volatiles from herbivore-damaged branches within blueberry plants. These methods are described here. Briefly, undamaged blueberry branches are exposed to HIPVs from neighboring branches within the same plant. Using the same techniques described above, volatiles emitted from branches after exposure to HIPVs are collected and analyzed.

A push-pull method for collecting plant volatiles is described. The method allows for a comparison of volatiles induced by herbivore feeding, exogenous methyl jasmonate, and mechanical damage. This technique is also used to investigate the volatile response of undamaged branches to exposure to volatiles from herbivore-damaged branches within blueberry plants.

Herbivore-induzierte Blueberry Volatile und Intra-Anlage Signaling

Herbivore-induced plant volatiles (HIPVs) are commonly emitted from plants after herbivore attack1,2.  These HIPVs are mainly regulated by the defensive ...

Measuring the Osmotic Water Permeability Coefficient (Pf) of Spherical Cells: Isolated Plant Protoplasts as an Example

Studying AQP regulation mechanisms is crucial for the understanding of water relations at both the cellular and the whole plant levels. Presented here is a simple and very efficient method for the determination of the osmotic water permeability coefficient (Pf) in plant protoplasts, applicable in principle also to other spherical cells such as frog oocytes. The first step of the assay is the isolation of protoplasts from the plant tissue of interest by enzymatic digestion into a chamber with an appropriate isotonic solution. The second step consists of an osmotic challenge assay: protoplasts immobilized on the bottom of the chamber are submitted to a constant perfusion starting with an isotonic solution and followed by a hypotonic solution. The cell swelling is video recorded. In the third step, the images are processed offline to yield volume changes, and the time course of the volume changes is correlated with the time course of the change in osmolarity of the chamber perfusion medium, using a curve fitting procedure written in Matlab (the &#8216;PfFit&#8217;), to yield Pf.

Measuring the Osmotic Water Permeability Coefficient Pf of Spherical Cells: Isolated Plant Protoplasts as an Example

Measuring the osmotic water permeability coefficient (Pf) of cells can help understand the regulatory mechanisms of aquaporins (AQPs). Pf determination in spherical plant cell protoplasts presented here involves protoplasts isolation and numerical analysis of their initial rate of volume change as a result of an osmotic challenge during constant bath perfusion.

Messung des osmotischen Wasserdurchlässigkeit Koeffizient (P<sub&gt; F</sub&gt;) Von sphärischen Zellen: Isolierte Pflanzenprotoplasten als Beispiel

Studying AQP regulation mechanisms is crucial for the understanding of water relations at both the cellular and the whole plant levels. Presented here is ...

The Infiltration-centrifugation Technique for Extraction of Apoplastic Fluid from Plant Leaves Using Phaseolus vulgaris as an Example

The apoplast is a distinct extracellular compartment in plant tissues that lies outside the plasma membrane and includes the cell wall. The apoplastic compartment of plant leaves is the site of several important biological processes, including cell wall formation, cellular nutrient and water uptake and export, plant-endophyte interactions and defence responses to pathogens. The infiltration-centrifugation method is well established as a robust technique for the analysis of the soluble apoplast composition of various plant species. The fluid obtained by this method is commonly known as apoplast washing fluid (AWF). The following protocol describes an optimized vacuum infiltration and centrifugation method for AWF extraction from Phaseolus vulgaris (French bean) cv. Tendergreen leaves. The limitations of this method and the optimization of the protocol for other plant species are discussed. Recovered AWF can be used in a wide range of downstream experiments that seek to characterize the composition of the apoplast and how it varies in response to plant species and genotype, plant development and environmental conditions, or to determine how microorganisms grow in apoplast fluid and respond to changes in its composition.

The Infiltration-centrifugation Technique for Extraction of Apoplastic Fluid from Plant Leaves Using Phaseolus vulgaris as an Example

This protocol details the optimized extraction of apoplast washing fluid from plant leaves, using French bean plants (Phaseolus vulgaris) as a model example.

Die Infiltration-Zentrifugation Technik zur Gewinnung von apoplastischen Flüssigkeit aus Pflanzenblättern verwenden<em&gt; Phaseolus vulgaris</em&gt; Als Beispiel

The apoplast is a distinct extracellular compartment in plant tissues that lies outside the plasma membrane and includes the cell wall. The apoplastic ...

Imaging FITC-dextran as a Reporter for Regulated Exocytosis

Regulated exocytosis is a process by which cargo, which is stored in secretory granules (SGs), is released in response to a secretory trigger. Regulated exocytosis is fundamental for intercellular communication and is a key mechanism for the secretion of neurotransmitters, hormones, inflammatory mediators, and other compounds, by a variety of cells. At least three distinct mechanisms are known for regulated exocytosis: full exocytosis, where a single SG fully fuses with the plasma membrane, kiss-and-run exocytosis, where a single SG transiently fuses with the plasma membrane, and compound exocytosis, where several SGs fuse with each other, prior to or after SG fusion with the plasma membrane. The type of regulated exocytosis undertaken by a cell is often dictated by the type of secretory trigger. However, in many cells, a single secretory trigger can activate multiple modes of regulated exocytosis simultaneously. Despite their abundance and importance across cell types and species, the mechanisms that determine the different modes of secretion are largely unresolved. One of the main challenges in investigating the different modes of regulated exocytosis, is the difficulty in distinguishing between them as well as exploring them separately. Here we describe the use of fluorescein isothiocyanate (FITC)-dextran as an exocytosis reporter, and live cell imaging, to differentiate between the different pathways of regulated exocytosis, focusing on compound exocytosis, based on the robustness and duration of the exocytic events.

Here we detail a method for live cell imaging of regulated exocytosis. This method utilizes FITC-dextran, which accumulates in lysosome-related organelles, as a reporter. This simple method also allows distinguishing between different modes of regulated exocytosis in cells that are difficult to manipulate genetically.

Imaging-FITC-Dextran als Reporter für regulierte Exozytose

Regulated exocytosis is a process by which cargo, which is stored in secretory granules (SGs), is released in response to a secretory trigger. Regulated ...

MRM Microcoil Performance Calibration and Usage Demonstrated on Medicago truncatula Roots at 22 T

This protocol describes a signal-to-noise ratio (SNR) calibration and sample preparation method for solenoidal microcoils combined with biological samples, designed for high-resolution magnetic resonance imaging (MRI), also referred to as MR microscopy (MRM). It may be used at pre-clinical MRI spectrometers, demonstrated on Medicago truncatula root samples. Microcoils increase sensitivity by matching the size of the RF resonator to the size of the sample of interest, thereby enabling higher image resolutions in a given data acquisition time. Due to the relatively simple design, solenoidal microcoils are straightforward and cheap to construct and can be easily adapted to the sample requirements. Systematically, we explain how to calibrate new or home-built microcoils, using a reference solution. The calibration steps include: pulse power determination using a nutation curve; estimation of RF-field homogeneity; and calculating a volume-normalized signal-to-noise ratio (SNR) using standard pulse sequences. Important steps in sample preparation for small biological samples are discussed, as well as possible mitigating factors such as magnetic susceptibility differences. The applications of an optimized solenoid coil are demonstrated by high-resolution (13 x 13 x 13 &#956;m3, 2.2 pL) 3D imaging of a root sample.

MRM Microcoil Performance Calibration and Usage Demonstrated on Medicago truncatula Roots at 22 T

A protocol to study biological tissue at high spatial resolution using ultra-high field magnetic resonance microscopy (MRM) using microcoils is presented. Step-by-step instructions are provided for characterizing the microcoils. Finally, optimization of imaging is demonstrated on plant roots.

MRM Microcoil Performance Calibration and Usage demonstriert auf Medicago-Truncatula-Wurzeln bei 22 T

This protocol describes a signal-to-noise ratio (SNR) calibration and sample preparation method for solenoidal microcoils combined with biological ...

Exploring m6A and m5C Epitranscriptomes upon Viral Infection: an Example with HIV

The role of RNA modifications in biological processes has been the focus of an increasing number of studies in the last few years and is known nowadays as epitranscriptomics. Among others, N6-methyladenosine (m6A) and 5-methylcytosine (m5C) RNA modifications have been described on mRNA molecules and may have a role in modulating cellular processes. Epitranscriptomics is thus a new layer of regulation that must be considered in addition to transcriptomic analyses, as it can also be altered or modulated by exposure to any chemical or biological agent, including viral infections.
Here, we present a workflow that allows analysis of the joint cellular and viral epitranscriptomic landscape of the m6A and m5C marks simultaneously, in cells infected or not with the human immunodeficiency virus (HIV). Upon mRNA isolation and fragmentation from HIV- infected and non-infected cells, we used two different procedures: MeRIP-Seq, an RNA immunoprecipitation-based technique, to enrich for RNA fragments containing the m6A mark and BS-Seq, a bisulfite conversion-based technique, to identify the m5C mark at a single nucleotide resolution. Upon methylation-specific capture, RNA libraries are prepared for high-throughput sequencing. We also developed a dedicated bioinformatics pipeline to identify differentially methylated (DM) transcripts independently from their basal expression profile.
Overall, the methodology allows exploration of multiple epitranscriptomic marks simultaneously and provides an atlas of DM transcripts upon viral infection or any other cell perturbation. This approach offers new opportunities to identify novel players and novel mechanisms of cell response, such as cellular factors promoting or restricting viral replication.

Exploring m6A and m5C Epitranscriptomes upon Viral Infection: an Example with HIV

The role of RNA modifications in viral infections is just starting to be explored and could highlight new viral-host interaction mechanisms. In this work, we provide a pipeline to investigate m6A and m5C RNA modifications in the context of viral infections.

Erforschung von m6A- und m5C-Epitranskriptomen bei Virusinfektion: ein Beispiel mit HIV

The role of RNA modifications in biological processes has been the focus of an increasing number of studies in the last few years and is known nowadays as ...

Characterizing Mechanical Properties of Primary Cell Wall in Living Plant Organs Using Atomic Force Microscopy

The mechanical properties of the primary cell walls determine the direction and rate of plant cell growth and, therefore, the future size and shape of the plant. Many sophisticated techniques have been developed to measure these properties; however, atomic force microscopy (AFM) remains the most convenient for studying cell wall elasticity at the cellular level. One of the most important limitations of this technique has been that only superficial or isolated living cells can be studied. Here, the use of atomic force microscopy to investigate the mechanical properties of primary cell walls belonging to the internal tissues of a plant body is presented. This protocol describes measurements of the apparent Young&#39;s modulus of cell walls in roots, but the method can also be applied to other plant organs. The measurements are performed on vibratome-derived sections of plant material in a liquid cell, which allows (i) avoiding the use of plasmolyzing solutions or sample impregnation with wax or resin, (ii) making the experiments fast, and (iii) preventing dehydration of the sample. Both anticlinal and periclinal cell walls can be studied, depending on how the specimen was sectioned. Differences in the mechanical properties of different tissues can be investigated in a single section. The protocol describes the principles of study planning, issues with specimen preparation and measurements, as well as the method of selecting force-deformation curves to avoid the influence of topography on the obtained values of elastic modulus. The method is not limited by sample size but is sensitive to cell size (i.e., cells with a large lumen are difficult to examine).

Studies of cell wall biomechanics are essential for understanding plant growth and morphogenesis. The following protocol is proposed to investigate thin primary cell walls in the internal tissues of young plant organs using atomic force microscopy.

Charakterisierung mechanischer Eigenschaften der primären Zellwand in lebenden Pflanzenorganen mittels Rasterkraftmikroskopie

The mechanical properties of the primary cell walls determine the direction and rate of plant cell growth and, therefore, the future size and shape of the ...

An Electroporation Method to Transform Rickettsia spp. with a Fluorescent Protein-Expressing Shuttle Vector in Tick Cell Lines

Rickettsioses are caused by a broad range of obligate intracellular bacteria belonging to the genus Rickettsia that can be transmitted to vertebrate hosts through the bite of infected arthropod vectors. To date, emerging or re-emerging epidemic rickettsioses remain a public health risk due to the difficulty in diagnosis, as diagnostic methods are limited and not standardized or universally accessible. Misdiagnosis resulting from a lack of recognition of the signs and symptoms may result in delayed antibiotic treatment and poor health outcomes. A comprehensive understanding of Rickettsia characteristics would ultimately improve clinical diagnosis, assessment, and treatment with improved control and prevention of the disease. 
Functional studies of rickettsial genes are crucial for understanding their role in pathogenesis. This paper describes a procedure for the electroporation of the Rickettsia parkeri strain Tate's Hell with the shuttle vector pRAM18dSFA and the selection of transformed R. parkeri in tick cell culture with antibiotics (spectinomycin and streptomycin). A method is also described for the localization of transformed R. parkeri in tick cells using confocal immunofluorescence microscopy, a useful technique for checking transformation in vector cell lines. Similar approaches are also suitable for the transformation of other rickettsiae.

An Electroporation Method to Transform Rickettsia spp. with a Fluorescent Protein-Expressing Shuttle Vector in Tick Cell Lines

Electroporation is a rapid, broadly adopted method for introducing exogenous DNA into the genus Rickettsia. This protocol provides a useful electroporation method for the transformation of obligate intracellular bacteria in the genus Rickettsia.

Eine Elektroporationsmethode zur Transformation von Rickettsien spp. mit einem fluoreszierenden Protein-exprimierenden Shuttle-Vektor in Zeckenzelllinien

Rickettsioses are caused by a broad range of obligate intracellular bacteria belonging to the genus Rickettsia that can be transmitted to vertebrate hosts ...

Monitoring On-Target Signaling Responses in Larval Zebrafish - Z-REX Unmasks Precise Mechanisms of Electrophilic Drugs and Metabolites

Reactive metabolites and related electrophilic drugs are among the most challenging small molecules to study. Conventional approaches to deconstruct the mode of action (MOA) of such molecules leverage bulk treatment of experimental specimens with an excess of a specific reactive species. In this approach, the high reactivity of electrophiles renders non-discriminate labeling of the proteome in a time- and context-dependent manner; redox-sensitive proteins and processes can also be indirectly and often irreversibly affected. Against such a backdrop of innumerable potential targets and indirect secondary effects, linking phenotype to specific target engagement remains a complex task. Zebrafish targeting reactive electrophiles and oxidants (Z-REX)-an on-demand reactive-electrophile delivery platform adapted for use in larval zebrafish-is designed to deliver electrophiles to a specific protein of interest (POI) in otherwise unperturbed live fish embryos. Key features of this technique include a low level of invasiveness, along with dosage-, chemotype-, and spatiotemporally-controlled precision electrophile delivery. Thus, in conjunction with a unique suite of controls, this technique sidesteps off-target effects and systemic toxicity, otherwise observed following uncontrolled bulk exposure of animals to reactive electrophiles and pleiotropic electrophilic drugs. Leveraging Z-REX, researchers can establish a foothold in the understanding of how individual stress responses and signaling outputs are altered as a result of specific reactive ligand engagement with a specific POI, under near-physiologic conditions in intact living animals.

Zebrafish targeting reactive electrophiles and oxidants (Z-REX) is a chemical biology-based method for the investigation of reactive small-molecule signaling. This technique can be applied to live fish of different developmental stages. Here, we couple standard assays in zebrafish with Z-REX for signaling pathway analysis.

Überwachung von On-Target-Signalantworten in Zebrafischlarven - Z-REX entschlüsselt präzise Mechanismen elektrophiler Wirkstoffe und Metaboliten

Reactive metabolites and related electrophilic drugs are among the most challenging small molecules to study. Conventional approaches to deconstruct the ...

Charakterisierung Herbivore Resistenzmechanismen: Spittlebugs auf Brachiaria Spp. als Beispiel

Zusammenfassung

Weitere Videos entdecken

Kapitel in diesem Video