Nicotiana benthamiana Pflanzen werden in einem temperierten Klimakammer bei 25 ° C gewachsen. Voll ausgebaut gesunde Blätter von 3-6 Wochen alten Pflanzen verwendet werden. Tipp: Bessere Ergebnisse werden mit neu entstehenden Blättern gewonnen 1. Agrobacterium vorübergehende Infiltration Protokoll: Tag 1 <ol><li> Streak LB / Rifampicin (25 ug / ml) / Kanamycin (100 ug / ml) Agarplatten mit Glycerin Aktien von Agrobacterium tumefaciens (Stamm LBA4404) mit den entsprechenden Vektoren mit dem Gen (s) zum Zelltod untersucht werden und der Vektor mit den GUS-Kassette unter einem konstitutiven Promotor. Enthalten immer eine leere Vektor-Regelung als negative Kontrolle. </li><li> Inkubation bei 28 ° C für 2 Tage. </li></ol> Tag 3 <ol><li> Inoculate 2 ml LB mit Rifampicin (25 ug / ml) und Kanamycin (100 ug / ml) mit einer einzelnen Kolonie von jeder LB / Rifampicin / Kanamycin Platte zuvor gestreift. </li><li> Inkubieren jede Kultur durch Schütteln bei 28 ° C für 24 Stunden bei 200 Umdrehungen pro Minute, bis ein maximales Wachstum Dichte erreicht ist. </li></ol> Tipp: Horstig ist manchmal zu beobachten, in welchem ​​Fall Kulturen gründlich resuspendiert werden (dh Auf-und Abpipettieren), bevor Sie fortfahren müssen. Tag 4 <ol><li> Nach der Inkubation erhöht das Gesamtvolumen auf 10 ml mit frischem LB (mit den entsprechenden Antibiotika) und Acetosyringon (Endkonzentration 25 uM). </li><li> Inkubieren jede Kultur durch Schütteln bei 28 ° C für weitere 16 Stunden. </li></ol> Tag 5 <ol><li> Am nächsten Tag waschen jede Kultur zweimal durch Zugabe von 10 ml (fügen Sie keine Acetosyringon) Infiltration Medium (10 mM MgSO 4 .7 H 2 O, 9 mM MES, pH 5,6) und zentrifugieren bei 4000 xg für 10 min bei Raumtemperatur. </li><li> Nach dem letzten Zentrifugationsschritt resuspendieren jede Kultur in 5 ml Medium mit Infiltration Acetosyringon (100 uM). </li><li> Messen Sie die OD 600nm, werden die Messungen zwischen 0,1 und 0,9 zulässig. Tipp: OD 600nm von nur 0,1 ohne Probleme verwendet wurden, können jedoch auch höhere OD produzieren mehr konsistente Ergebnisse. </li><li> Inkubieren Sie die Kulturen weitere 3 Stunden auf die Agrobacterium Kulturen zur Infektion vorzubereiten. </li><li> Mix Kulturen, die das Gen (s) zu analysieren und die Negativ-Kontrolle (Agrobacterium mit dem leeren Vektor) in einem Verhältnis von 1:1 mit der Kultur, die das GUS-Kassette. </li><li> Infiltrate der abaxialen (unter-) Seite neu entstehenden Blätter mit einer 1 ml nadellose Spritze (Abb. 1). Tipp: Infiltrate sowohl die Negativ-Kontrolle-Gemisch (Leervektor + GUS-Kassette) und die Mischung, die das Gen zu untersuchenden (Gen x + GUS-Kassette) auf gegenüberliegenden Blätter der gleichen Pflanze. Verwenden Sie dreifach Pflanzen für jede Behandlung. </li><li> 3 Tage nach Infiltration Verbrauchsteuern infiltriert Blätter und Assay für GUS-Protein-Expression. </li></ol> 2. Histochemische GUS-Test Tag 8 <ol><li> Vacuum infiltrieren die X-Gluc Trägermedium in die ausgeschnittene Blätter. </li><li> Inkubieren im Dunkeln über Nacht bei Raumtemperatur oder bis deutliche Blau-Färbung erscheint. </li></ol> Tag 9 <ol><li> Spülen in destilliertem Wasser. </li><li> Inkubieren in 70% Ethanol bis Chlorophyll entfernt wird, dann Transfer zum destilliertem Wasser wieder. Optisch bewerten GUS-Expression Ebenen. </li></ol> 3. Fluorometric MUG-Assay: Tag 8 <ol><li> Isolieren gesamten Proteins durch Schleifen infiltriert Blattscheiben in einem Mörser mit flüssigem Stickstoff. Add 100 uL der GUS-Extraktionspuffer (50 mM NaPi pH 7,0, 10 mM EDTA, 0,1% Triton X-100, 0,1% N-Lauroylsarcosin Natriumsalz, β-Mercaptoethanol (0,7 ul / ml), während die Probe auf Eis. </li><li> Centrifuge Suspension bei 14.000 g für 5 min bei 4 ° C und nehmen Überstand als Gesamt-lösliches Protein. </li><li> Measure-Konzentration mit Hilfe eines NanoDrop nach den Anweisungen des Herstellers. </li><li> Passen Sie die Protein-Konzentration auf 100 ug Gesamt-lösliches Protein für jede Probe mit GUS-Extraktionspuffer. </li><li> Add MUG Substrat (4-Methylumbelliferyl-β-D-Glucuronid Trihydrat) in GUS-Extraktionspuffer zu einer Endkonzentration von 2 mM hergestellt. Ein Gesamtvolumen von 100 mL pro Probe (Protein + MUG Substrat) sollte ausreichend sein. </li><li> Inkubieren Sie die Reaktionen für 1 Stunde bei 37 ° C. </li><li> Stop-Reaktionen durch Zugabe von 800 ul GUS Stop Puffer (0,2 M Na 2 CO 3). </li><li> Messen Sie mit einem Fluoreszenz-Reader bei einer Anregungswellenlänge von 365 nm und Emissionswellenlänge von 455 nm und Werte vergleichen zu einem MU Standardkurve. Bericht Ebenen der GUS-Aktivität als nmol MU / ug gesamte lösliche Protein / min. </li></ol> 4. Stocks and Solutions: <ol><li> Acetosyringon (1 M) Aktie (FW = 196,2 g) </sub&gt; - 0,981 g in 5 ml DMSO </li><li> Kanamycin (100 mg / ml) auf Lager - in dH vorbereiten 2 0 - Filter sterilisieren </li><li> Rifampicin (25 mg / ml) auf Lager - in DMSO vorbereiten </li><li> Luria-Bertani (LB) flüssige Nährmedien: (1L) 1% (w / v) Bacto-Trypton, 10 g 0,5% (w / v) Bacto-Hefeextrakt, 5 g 170 mM Natriumchlorid 10 g pH - 7 </li><li> Acetosyringon (25 nM) = 25 ul einer 1 M Stammlösung in einem Endvolumen von 1 ml </li><li> Infiltration Medium: (1L) 10 mM MgSO 4 .7 dH 2 0 (FW = 246,48 g), 2,4648 g 9 mM MES (FW = 213,25 g), 1,91925 g pH - 5,6 </li><li> Acetosyringon (100 uM) = 100 ul einer 1M Lager in einem Endvolumen von 1 ml </li><li> GUS-Extraktionspuffer 50 mM NaPi pH 7,0, 10 mM EDTA, 0,1% Triton X-100, 0,1% N-Lauroylsarcosin Natriumsalz, β-Mercaptoethanol (0,7 ul / ml) </li><li> 2x Phosphatpuffer 0,2 M NaH 2 PO 4 und 0,2 M Na 2 HPO 4 pH 7 </li><li> X-Gluc Substrat-Lösung 1 mg 5-Brom-4-Chlor-3-Indolyl bD-Glucuronid (X-Gluc) in 0,1 ml Methanol. 1 ml 2x Phosphat-Puffer, 20 ul 0,1 M Kaliumferricyanid, 10 &amp;mgr; l Triton X-100 10% und 850 ul destilliertes Wasser. </li></ol> 5. Repräsentative Ergebnisse: Nach diesem Protokoll ist der Verlust der GUS-Expression zu erwarten, wenn Zelltod eintritt. Wir haben gleichzeitig das Reporter-Gen, β-Glucuronidase (GUS) mit einem Mitglied des Zyto-Schutz Arabidopsis Bcl-2 assoziierte athanoGene (BAG) Familie zum Ausdruck gebracht. Wir co-infiltriert N. benthamiana Blätter mit einem 35S angetrieben BAG Expressionskassette und die GUS-Vektor pCAMBIA 2301 unter Verwendung von Agrobacterium LBA4404. Wie in Abbildung 2 gezeigt, wurde eine sichtbare Steigerung der GUS-Färbung nach dieser Infiltration beobachtet. Umgekehrt, wenn die bekannten pro-apoptotischen Mitglied der Bcl-2 Familie BAX verwendet wurde, war eine deutliche Reduktion der GUS-Färbung beobachtet werden (Abb. 2). In beiden Fällen wurde GUS-Expression sichtbar anders im Vergleich zur Kontrollgruppe. Allerdings, wenn der Unterschied im Ausdruck weniger offensichtlich ist, kann fluorometrische MUG-Assays durchgeführt, um GUS-Expression quanitate werden. <img src="/files/ftp_upload/2680/2680fig1.jpg" alt="Abbildung 1"/> Abbildung 1. Beispiel Agrobacterium Mischung Infiltration der abaxialen Seite des N. benthamiana Blätter mit einer 1 ml nadellose Spritze. <img src="/files/ftp_upload/2680/2680fig2.jpg" alt="Abbildung 2"/> Abbildung 2. A GUS-Vektor wurde in N. co-exprimiert benthamiana Blätter mit dem Anti-Todes-Gen, und ein bekannter Induktor von Zelltod. GUS-Spiegel wurden in ein leeres Vector-Regelung (GUS Kontrolle) verglichen.

<ol>
	<li>Jefferson, R. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=GUS+fusions:+,+&#946;-glucuronidase+as+a+sensitive+and+versatile+gene+fusion+marker+in+higher+plants.">GUS fusions: , &#946;-glucuronidase as a sensitive and versatile gene fusion marker in higher plants.</a> EMBO J. 6, 3901-3901 (1987).</li><li>Nishihara, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Expression+of+the+&#946;-Glucuronidase+Gene+in+Pollen+of+Lily+(Lilium+longiflorum),+Tobacco+(Nicotiana+tabacum),+Nicotiana+rustica,+and+Peony+(Paeonia+lactiflora)+by+Particle+Bombardment.">Expression of the &#946;-Glucuronidase Gene in Pollen of Lily (Lilium longiflorum), Tobacco (Nicotiana tabacum), Nicotiana rustica, and Peony (Paeonia lactiflora) by Particle Bombardment.</a> Plant Physiol. 102, 357-357 (1993).</li><li>Hodal, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Plant Science. 87, 115-115 (1992).</li><li>Kabbage, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+BAG+proteins:+a+ubiquitous+family+of+chaperone+regulators.">The BAG proteins: a ubiquitous family of chaperone regulators.</a> Cell Mol. Life Sci. . 65, 1390-1390 (2008).</li><li>Kang, C. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=AtBAG6,+a+novel+calmodulin-binding+protein,+induces+programmed+cell+death+in+yeast+and+plants.">AtBAG6, a novel calmodulin-binding protein, induces programmed cell death in yeast and plants.</a> Cell Death Differ. 13 (1), 84-84 (2006).</li><li>Yan, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Plant Science. 165 (1), 1-1 (2006).</li><li>Takayama, S., Reed, J. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Molecular+chaperone+targeting+and+regulation+by+BAG+family+proteins.">Molecular chaperone targeting and regulation by BAG family proteins.</a> Nat Cell Biol. 3 (10), 237-237 (2001).</li><li>Takayama, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cloning+and+functional+analysis+of+BAG-1:+a+novel+Bcl-2-binding+protein+with+anti-cell+death+activity.">Cloning and functional analysis of BAG-1: a novel Bcl-2-binding protein with anti-cell death activity.</a> Cell. 80 (2), 279-279 (1995).</li><li>Vitha, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Quantitative+&#946;-glucuronidase+assay+in+transgenic+plants.">Quantitative &#946;-glucuronidase assay in transgenic plants.</a> Biol. Plant. 35, 151-151 (1993).</li><li>Otha, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Construction+and+Expression+in+Tobacco+of+a+&#946;-Glucuronidase+(GUS)+Reporter+Gene+Containing+an+Intron+Within+the+Coding+Sequence.">Construction and Expression in Tobacco of a &#946;-Glucuronidase (GUS) Reporter Gene Containing an Intron Within the Coding Sequence.</a> Plant Cell Physiol. 31, 805-805 (1990).</li></ol>

<p class="jove_content"&gt; Es ist oft schwierig, den Zelltod Nachweisverfahren in Pflanzen, die häufig in Säugetier-Systemen verwenden. In Kombination mit einem GUS-Reporter-System präsentieren wir ein auf pflanzlicher Basis, empfindliche Methode zum Nachweis und zur Analyse von Zelltod Spieler. Diese Methode nutzt die Tatsache, dass lebende Zellen für GUS-Expression auftreten, sind erforderlich. Um sicherzustellen, aussagekräftige Ergebnisse und Wiederholbarkeit, ist es entscheidend, dass die Kulturen beherbergen die GUS-Kassette und das...

<table border="1"><tbody><tr><th> Name des Reagenzes </th><th> Firma </th><th> Katalog-Nummer </th><th> Kommentare (optional) </th></tr><tr><td> Rifampicin </td><td> VWR </td><td> IC19549001 </td><td> 25mg/ml Lager in DMSO </td></tr><tr><td> 4&#39;-Hydroxy-3 &#39;, 5&#39;-Dimethoxyacetophenon (Acetosyringon) </td><td> VWR </td><td> TCD2666 </td><td> 0,981 g / mL in DMSO (1M Lager) </td></tr><tr><td> 2 - (4-Morpholino) ethansulfonsäure Monohydrat (MES) </td><td> VWR </td><td> EM-6110 </td><td> 1,92 g / L in Wasser zur Herstellung von 1 L der Infiltration Medien </td></tr><tr><td> Bacto-Trypton </td><td> Fischer </td><td> BP1421-2 </td><td> 10g / L in Wasser zur Herstellung von 1 L LB-Medium </td></tr><tr><td> Bacto-Hefeextrakt </td><td> VWR </td><td> EM1.03753.0500 </td><td> 5g / L in Wasser zur Herstellung von 1 L LB-Medium </td></tr><tr><td> Kochsalz </td><td> VWR </td><td> EM-7710 </td><td> 10g / L in Wasser zur Herstellung von 1 L LB-Medium </td></tr><tr><td> Mononatriumphosphat Monohydrat </td><td> VWR </td><td> MK-7868 bis 12 </td><td> 2,5 g / L in Wasser zur Herstellung von 50mm Puffer NaPi </td></tr><tr><td> Natriumdihydrogenphosphat Heptahydrat </td><td> VWR </td><td> EMD-SX0715-1 </td><td> 5g / L in Wasser zur Herstellung von 50mm Puffer NaPi </td></tr><tr><td> Magnesiumsulfatheptahydrat </td><td> VWR </td><td> EM-MX0070-1 </td><td> 2,5 g / L in Wasser zur Herstellung von 1 L der Infiltration Medien </td></tr><tr><td> N-Lauroylsarcosin </td><td> VWR </td><td> TCL0151-500G </td><td> 0,1% v / v in GUS-Puffer </td></tr><tr><td> 5-Bromo-4-Chlor-3-Indoxyl-beta-D-Glucuronid Cyclohexylammoniumsalz (X-Gluc) </td><td> Gold-Biotechnologie </td><td> G1281C </td><td> 1mg/100uL in Methanol 100% </td></tr><tr><td> 4-Methyl-μ-D-Glucuronid-Hydrat (MUG) </td><td> Sigma </td><td> M5664 </td><td> 2 mM in 100 uL der GUS-Extraktionspuffer </td></tr><tr><td> Kaliumferrocyanid Trihydrat </td><td> VWR </td><td> EM-PX1460-1 </td><td> 100 mM Stammlösung für X-Gluc Substrat-Lösung </td></tr><tr><td> β-Methylumbelliferon (MU) </td><td> Sigma-Aldrich </td><td> M1381 </td><td> Für MU Standardkurve verwenden GUS-Extraktionspuffer </td></tr><tr><td> Natriumcarbonat </td><td> VWR </td><td> EM-SX0395-11 </td><td> 0,2 M in Wasser zur Herstellung von GUS Anschlagpuffer </td></tr></tbody></table>

a &#946;-glucuronidase (gus) based cell death assay

Wir haben eine neue vorübergehende Anlage Ausdruck System, das gleichzeitig Ausdruck der Reportergen β-Glucuronidase (GUS), mit vermeintlichen positive oder negative Regulatoren des Zelltods entwickelt. In diesem System, N. benthamiana Blätter sind mit einer 35S angetrieben Expressionskassette enthält das Gen analysiert werden co-infiltriert, und die GUS-Vektor pCAMBIA 2301 unter Verwendung von Agrobacterium LBA4404 als Vehikel. Da lebende Zellen benötigt werden für die GUS-Expression auftritt, ist der Verlust der GUS-Aktivität zu erwarten, wenn dieses Markergen wird mit positiven Regulatoren des Zelltods co-exprimiert. Ebenso erhöhte GUS-Aktivität beobachtet wird, wenn anti-apoptotischen Gene im Vergleich zu den Vektor-Steuerung verwendet werden. Wie unten gezeigt, haben wir erfolgreich dieses System in unserem Labor verwendet, um sowohl pro-und anti-death-Spieler zu analysieren. Dazu gehören die Anlage anti-apoptotischen Bcl-2 assoziierte athanoGene (BAG) Familie, sowie bekannte Säugetier-Induktoren von Zelltod, wie BAX. Darüber hinaus haben wir dieses System verwendet, um den Tod in Abhängigkeit von bestimmten Verkürzungen innerhalb Proteinen, die Hinweise auf die mögliche posttranslationale Modifikation / Aktivierung dieser Proteine ​​könnte zu analysieren. Hier präsentieren wir eine schnelle und empfindliche Pflanzen basierende Methode, als einen ersten Schritt bei der Untersuchung des Todes Funktion bestimmter Gene.

Watch this Scientific Journal Video about A Î²-glucuronidase GUS Based Cell Death Assay at JoVE.com

A &amp;#946;-glucuronidase GUS Based Cell Death Assay

Der programmierte Zelltod-Assays häufig in Säugetier-Systemen wie DNA laddering oder TUNEL-Assays, sind oft nur schwer in Pflanzen zu reproduzieren. In Kombination mit einem GUS-Reporter-Systems, schlagen wir eine schnelle, auf pflanzlicher Basis transienten Assay, um das Potenzial der Tod Eigenschaften bestimmter Gene zu analysieren.

Eine β-Glucuronidase (GUS) Basierend Cell Death Assay

We have developed a novel transient plant expression system that simultaneously expresses the reporter gene, &beta;-glucuronidase (GUS), with putative ...

a-glucuronidase-gus-based-cell-death-assay

Research

JoVE Journal

Biology

A &#946;-glucuronidase (GUS) Based Cell Death Assay

28.0K Aufrufe.  Texas A&M University. Der programmierte Zelltod-Assays häufig in Säugetier-Systemen wie DNA laddering oder TUNEL-Assays, sind oft nur schwer in Pflanzen zu reproduzieren. In Kombination mit einem GUS-Reporter-Systems, schlagen wir eine schnelle, auf pflanzlicher Basis transienten Assay, um das Potenzial der Tod Eigenschaften bestimmter Gene zu analysieren.

Serie: A &#946;-glucuronidase GUS Based Cell Death Assay

Studying Membrane Biogenesis with a Luciferase-Based Reporter Gene Assay

To study the coordination of different lipid synthesis pathways during membrane biogenesis it is useful to work with an experimental system where membrane biogenesis occurs rapidly and in an inducible manner. We have found that phagocytosis of latex beads is practical for these purposes as cells rapidly synthesize membrane lipids to replenish membrane pools lost as  wrapping material  during particle engulfment. Here, we describe procedures for studying changes in phagocytosis-induced gene expression with a luciferase-based reporter gene approach using the Dual-Glo  Luciferase Assay System from Promega.

Here, we describe procedures for studying changes in phagocytosis-induced gene expression with a luciferase-based reporter gene approach using the Dual-GloTM Luciferase Assay System from Promega.

Studieren Membrane Biogenesis mit einem Luciferase-Based Reporter Gene Assay

To study the coordination of different lipid synthesis pathways during membrane biogenesis it is useful to work with an experimental system where membrane ...

Forschung

Biologie

Modified Annexin V/Propidium Iodide Apoptosis Assay For Accurate Assessment of Cell Death

Studies of cellular apoptosis have been significantly impacted since the introduction of flow cytometry-based methods. Propidium iodide (PI) is widely used in conjunction with Annexin V to determine if cells are viable, apoptotic, or necrotic through differences in plasma membrane integrity and permeability1,2. The Annexin V/ PI protocol is a commonly used approach for studying apoptotic cells3. PI is used more often than other nuclear stains because it is economical, stable and a good indicator of cell viability, based on its capacity to exclude dye in living cells 4,5. The ability of PI to enter a cell is dependent upon the permeability of the membrane; PI does not stain live or early apoptotic cells due to the presence of an intact plasma membrane 1,2,6. In late apoptotic and necrotic cells, the integrity of the plasma and nuclear membranes decreases7,8, allowing PI to pass through the membranes, intercalate into nucleic acids, and display red fluorescence 1,2,9. Unfortunately, we find that conventional Annexin V/ PI protocols lead to a significant number of false positive events (up to 40%), which are associated with PI staining of RNA within the cytoplasmic compartment10. Primary cells and cell lines in a broad range of animal models are affected, with large cells (nuclear: cytoplasmic ratios &lt;0.5) showing the highest occurrence10. Herein, we demonstrate a modified Annexin V/ PI method that provides a significant improvement for assessment of cell death compared to conventional methods. This protocol takes advantage of changes in cellular permeability during cell fixing to promote entry of RNase A into cells following staining. Both the timing and concentration of RNase A have been optimized for removal of cytoplasmic RNA. The result is a significant improvement over conventional Annexin V/ PI protocols (&lt; 5% events with cytoplasmic PI staining).

An accurate method for the assessment of cell death is described. The protocol improves upon conventional Annexin V/ propidium iodide (PI) protocols, which display up to 40% false- positive events in cell lines and primary cells from a broad range of animal models.

Geändert Annexin V / Propidiumiodid Apoptose Assay für eine genaue Beurteilung des Zelltods

Studies of cellular apoptosis have been significantly impacted since the introduction of flow cytometry-based methods. Propidium iodide (PI) is widely ...

Modified Mouse Embryonic Stem Cell based Assay for Quantifying  Cardiogenic Induction Efficiency

Differentiation of pluripotent stem cells is tightly controlled by temporal and spatial regulation of multiple key signaling pathways. One of the hurdles to its understanding has been the varied methods in correlating changes of key signaling events to differentiation efficiency. We describe here the use of a mouse embryonic stem (ES) cell based assay to identify critical time windows for Wnt/&beta;-catenin and BMP signal activation during cardiogenic induction. By scoring for contracting embryonic bodies (EBs) in a 96-well plate format, we can quickly quantify cardiogenic efficiency and identify crucial time windows for Wnt/&beta;-catenin and BMP signal activation in a time course following specific modulator treatments. The principal outlined here is not limited to cardiac induction alone, and can be applied towards the study of many other cell lineages. In addition, the 96-well format has the potential to be further developed as a high throughput, automated assay to allow for the testing of more sophisticated experimental hypotheses.

We describe the use of a mouse ES cell based assay to identify critical time windows for Wnt/&#946;-catenin and BMP signal activation during cardiogenic induction. The method provides a standardized platform that reliably quantifies cardiogenic efficiency, and it is applicable to the study of other cell lineages.

Geändert Maus embryonalen Stammzellen basierte Assay zur Quantifizierung von Kardiogener Induction Efficiency

Differentiation of pluripotent stem cells is tightly controlled by temporal and spatial regulation of multiple key signaling pathways.  One of the hurdles ...

Analysis of Global RNA Synthesis at the Single Cell Level following Hypoxia

Hypoxia or lowering of the oxygen availability is involved in many physiological and pathological processes. At the molecular level, cells initiate a particular transcriptional program in order to mount an appropriate and coordinated cellular response. The cell possesses several oxygen sensor enzymes that require molecular oxygen as cofactor for their activity. These range from prolyl-hydroxylases to histone demethylases. The majority of studies analyzing cellular responses to hypoxia are based on cellular populations and average studies, and as such single cell analysis of hypoxic cells are seldom performed. Here we describe a method of analysis of global RNA synthesis at the single cell level in hypoxia by using Click-iT RNA imaging kits in an oxygen controlled workstation, followed by microscopy analysis and quantification.&nbsp; Using cancer cells exposed to hypoxia for different lengths of time, RNA is labeled and measured in each cell. This analysis allows the visualization of temporal and cell-to-cell changes in global RNA synthesis following hypoxic stress.

We describe a technique for analysis of global RNA synthesis in hypoxia using imaging. Click-chemistry labeling of RNA has not previously been performed under hypoxia and allows visualization of global RNA changes at the single cell level. This approach complements the existing averaged RNA techniques, allowing direct visualization of cell-to-cell changes in global RNA synthesis.

Analyse der globalen RNA-Synthese auf der Einzelzellebene folgende Hypoxie

Hypoxia or lowering of the oxygen availability is involved in many physiological and pathological processes. At the molecular level, cells initiate a ...

A Simple Fluorescence-based Reporter Assay to Identify Cellular Components Required for Ricin Toxin A Chain (RTA) Trafficking in Yeast

Bacterial and plant A/B toxins exploit the natural trafficking pathways in eukaryotic cells to reach their intracellular target(s) in the cytosol and to ultimately kill. Such A/B toxins generally consist of an enzymatically active Asubunit (e.g., ricin toxin A (RTA)) and one or more cell binding Bsubunit(s), which are responsible for toxin binding to specific cell surface receptors. Our current knowledge of how A/B toxins are capable of efficiently intoxicating cells helped scientists to understand fundamental cellular mechanisms, like endocytosis and intracellular protein sorting in higher eukaryotic cells. From a medical point of view, it is likewise important to identify the major toxin trafficking routes to find adequate treatment solutions for patients or to eventually develop therapeutic toxin-based applications for cancer therapy.
Since genome-wide analyses of A/B toxin trafficking in mammalian cells is complex, time-consuming, and expensive, several studies on A/B toxin transport have been performed in the yeast model organism Saccharomyces cerevisiae. Despite being less complex, fundamental cellular processes in yeast and higher eukaryotic cells are similar and very often results obtained in yeast can be transferred to the mammalian situation.
Here, we describe a fast and easy to use reporter assay to analyze the intracellular trafficking of RTA in yeast. An essential advantage of the new assay is the opportunity to investigate not only RTA retro-translocation from the endoplasmic reticulum (ER) into the cytosol, but rather endocytosis and retrograde toxin transport from the plasma membrane into the ER. The assay makes use of a reporter plasmid that allows indirect measurement of RTA toxicity through fluorescence emission of the green fluorescent protein (GFP) after in vivo translation. Since RTA efficiently prevents the initiation of protein biosynthesis by 28S rRNA depurination, this assay allows the identification of host cell proteins involved in intracellular RTA transport through the detection of changes in fluorescence emission.

A Simple Fluorescence-based Reporter Assay to Identify Cellular Components Required for Ricin Toxin A Chain RTA Trafficking in Yeast

In the manuscript, we describe the use of a yeast-based fluorescence reporter assay to identify cellular components involved in the trafficking and killing processes of the cytotoxic A subunit of the plant toxin ricin (RTA).

Ein einfache Fluoreszenz basierende Reporter Assay zelluläre Komponenten identifizieren erforderlich für Ricin Toxin eine Kette (RTA) Handel mit Hefe

Bacterial and plant A/B toxins exploit the natural trafficking pathways in eukaryotic cells to reach their intracellular target(s) in the cytosol and to ...

The Microscopy-Based Assay to Study and Analyze the Recycling Endosomes using SNARE Trafficking

Recycling endosomes (REs) are tubular-vesicular organelles generated from early/sorting endosomes in all cell types. These organelles play a key role in the biogenesis of melanosomes, a lysosome-related organelle produced by melanocytes. REs deliver the melanocyte-specific cargo to premature melanosomes during their formation. Blockage in the generation of REs, observed in several mutants of Hermansky-Pudlak syndrome, results in hypopigmentation of skin, hair, and eye. Therefore, studying the dynamics (refer to number and length) of REs is useful to understand the function of these organelles in normal and disease conditions. In this study, we aim to measure the RE dynamics using a resident SNARE STX13.

Recycling endosomes are part of the endosomal tubular network. Here we present a method to quantify the dynamics of recycling endosomes using GFP-STX13 as an organelle marker.

Der mikroskopiebasierte Assay zur Untersuchung und Analyse der Recycling-Endosomen mittels SNARE-Trafficking

Recycling endosomes (REs) are tubular-vesicular organelles generated from early/sorting endosomes in all cell types. These organelles play a key role in ...

A Step-By-Step Method to Detect Neutralizing Antibodies Against AAV using a Colorimetric Cell-Based Assay

Recombinant adeno-associated viruses (rAAV) have proven to be a safe and successful vector for transferring genetic material to treat various health conditions in both the laboratory and the clinic. However, pre-existing neutralizing antibodies (NAbs) against AAV capsids pose an ongoing challenge for the successful administration of gene therapies in both large animal experimental models and human populations. Preliminary screening for host immunity against AAV is necessary to ensure the efficacy of AAV-based gene therapies as both a research tool and as a clinically viable therapeutic agent. This protocol describes a colorimetric in vitro assay to detect neutralizing factors against AAV serotype 6 (AAV6). The assay utilizes the reaction between an AAV encoding an alkaline phosphatase (AP) reporter gene and its substrate NBT/BCIP, which generates an insoluble quantifiable purple stain upon combination. 
In this protocol, serum samples are combined with an AAV expressing AP and incubated to permit potential neutralizing activity to occur. Virus serum mixture is subsequently added to cells to allow for viral transduction of any AAVs that have not been neutralized. The NBT/BCIP substrate is added and undergoes a chromogenic reaction, corresponding to viral transduction and neutralizing activity. The proportion of area colored is quantitated using a free software tool to generate neutralizing titers. This assay displays a strong positive correlation between coloration and viral concentration. Assessment of serum samples from sheep before and after administration of a recombinant AAV6 led to a dramatic increase in neutralizing activity (125 to &gt;10,000-fold increase). The assay displayed adequate sensitivity to detect neutralizing activity in &gt;1:32,000 serum dilutions. This assay provides a simple, rapid, and cost-effective method to detect NAbs against AAVs.

A comprehensive laboratory protocol and analysis workflow are described for a rapid, cost-effective, and straightforward colorimetric cell-based assay to detect neutralizing elements against AAV6.

Eine Schritt-für-Schritt-Methode zum Nachweis neutralisierender Antikörper gegen AAV mit einem kolorimetrischen zellbasierten Assay

Recombinant adeno-associated viruses (rAAV) have proven to be a safe and successful vector for transferring genetic material to treat various health ...

Histology Basics and Cell Death Detection in Honeybee Tissue

Honeybees (Apis mellifera L.) inside the hive (nurse workers and other hive bees) and outside the hive (foragers) are exposed to climate and weather changes, various pesticides, pathogens, and malnutrition, mainly entering through the mouth and primarily affecting the digestive tracts of adult bees. To understand and prevent the effects of such external and internal stressors on honeybees, one useful research method is the immunohistochemical method. A basic protocol is described to prepare the midgut (ventriculus) and hypopharyngeal glands (HPGs) of adult bees for histological analysis. A detailed methodology is described to assess the level of cell damage and distinguish necrosis from programmed cell death (apoptosis) as a natural process of tissue regeneration. The results of adult honeybee treatment with oxalic acid and pesticides (insecticide and acaricide) and the determination of cell death in the ventriculus and HPGs are presented. The pros and cons of the methodology are also discussed.

Immunohistochemical methods are useful in honeybee research to detect and assess the level of apoptosis and necrosis in the midgut and hypopharyngeal glands of adult bees.

Histologische Grundlagen und Zelltodnachweis in Honigbienengewebe

Honeybees (Apis mellifera L.) inside the hive (nurse workers and other hive bees) and outside the hive (foragers) are exposed to climate and weather ...

Neutrophil Lifespan Extension with CLON-G and an In Vitro Spontaneous Death Assay

The average lifespan of a neutrophil is less than 24 h, which limits basic research on neutrophils and the application of neutrophil studies. Our previous research indicated that multiple pathways could mediate the spontaneous death of neutrophils. A cocktail was developed by simultaneously targeting these pathways, caspases-lysosomal membrane permeabilization-oxidant-necroptosis inhibition plus granulocyte colony-stimulating factor (CLON-G), which prolonged the neutrophil lifespan to greater than 5 days without significantly compromising the neutrophil function. Concurrently, a reliable and stable protocol for assessing and evaluating neutrophil death was also developed. In this work, we show that CLON-G can prolong the neutrophil lifespan in vitro to more than 5 days, and we exhibit the lengthening of the neutrophil lifespan with FACS and confocal fluorescence microscopy. This report introduces procedures for the preparation of CLON-G and showcases an in vitro spontaneous death assay of neutrophils, which can be used for the study of neutrophils and for subsequently interrogating neutrophil death, thus providing a reliable resource for the neutrophil community.

Neutrophil Lifespan Extension with CLON-G and an In Vitro Spontaneous Death Assay

This protocol details the preparation of CLON-G to extend the neutrophil lifespan to greater than 5 days and provides a reliable procedure for evaluating neutrophil death with flow cytometry and confocal fluorescence microscopy.

Verlängerung der Lebensdauer von Neutrophilen mit CLON-G und einem In-vitro-Spontantod-Assay

The average lifespan of a neutrophil is less than 24 h, which limits basic research on neutrophils and the application of neutrophil studies. Our previous ...

Quantifizierung der Initiierung des Zelltods durch kontinuierliche Bildgebung

Studying Cell Death Initiation Using a Digital Microscope

Hypersensitive response (HR)-conferred resistance is an effective defense response that can be determined by the N resistance genes. HR is manifested as the formation of cell death zones on inoculated leaves. Here, a protocol for studying the rate of cell death initiation by imaging inoculated leaves in the time between the cell death initiation and the cell death appearance using a digital microscope is presented. The digital microscope enables a continuous imaging process in desired intervals, which allows an accurate determination of cell death initiation rate up to minutes exactly, as opposed to hours in traditional methods. Imaging with the digital microscope is also independent of light and can therefore be used during day and night without disturbing the circadian rhythm of the plant. Different pathosystems resulting in programmed cell death development could be studied using this protocol with minor modifications. Overall, the protocol thus allows simple, accurate, and inexpensive identification of cell death initiation rate.

Autor im Rampenlicht: Ein optimierter Ansatz zur Untersuchung der Initiierung des Zelltods bei hypersensitiver Reaktion 

Here we present a protocol for studying the rate of programmed cell death initiation by continuously imaging inoculated leaves following cell death induction.

Untersuchung der Initiierung des Zelltods mit einem digitalen Mikroskop

Hypersensitive response (HR)-conferred resistance is an effective defense response that can be determined by the N resistance genes. HR is manifested as ...