Ein. Beschreibung von Tracking-Mikroskop <ol><li> Eine Agarplatte wird durch eine Faser-Lichtquelle beleuchtet und abgebildet mit einer Kamera. Dieses System wird auf einen X, Y Translationstisch montiert ist. </li><li> Die Stufe wird durch Standard-Schrittmotoren, die mit einem Schrittmotor-Controller verbunden bewegt werden. </li><li> Der Controller und die Kamera mit dem Computer verbunden ist und durch individuelle Programme in LabVIEW geschrieben. </li><li> Die Kamera Bilder der Oberfläche einer Agarplatte und identifiziert dunkle Objekte auf einem hellen Hintergrund. </li><li> Die Bildqualität wird so eingestellt, dass Computerprogramm kann Objekte in Echtzeit zu quantifizieren. Die Verstärkung, der Helligkeit und Verschlußzeit der Kamera eingestellt werden, um einen dunklen Objekts auf einem weißen Hintergrund zu liefern. </li><li> A Eichmarke für die automatische Kalibrierung wird durch Stossen die Agar-Oberfläche mit einem Wurm Pick gemacht. </li><li> Die gefilterten binären Bildes, das durch den Tracking-Programm verwendet wird, kann geprüft werden. </li><li> Die software hat eine Auto-Kalibrierung Funktion, die Kalibriermatrix berechnet, indem ein Testobjekt einen festen Abstand. </li><li> Abstände in Pixeln zu den Schritten von dem Schrittmotor durch die Kalibrierungsmatrix genommen kalibriert. </li><li> Nach der Kalibrierung ist das System bereit zu gehen und muss nicht neu kalibriert werden, wenn die Vergrößerung verändert wird oder wenn die Kamera neu positioniert. </li></ol> 2. Vorbereiten Spurplatten und C. elegans für Tracking <ol><li> Ein Kupfer-Ring wird verwendet, um die Würmer corral und halten sie von der Migration auf die Kante der Platte. Das Kupfer stellt eine lokale chemische Barriere und beeinflusst nicht die Bewegung der Schnecke sonst für die Dauer des Experiments (&lt;1 h). Heizen Sie den Ring zuerst, indem sie auf einem Heizblock oder gleichwertig. </li><li> Muffel auf eine frische Agarplatte (1,7% Bacto Agar, 0,25% Bacto-Pepton, 0,3% NaCl, 1 mM CaCl 2, 1 mM MgSO 4, 25 mM Kaliumphosphatpuffer, 5 pg / mlCholesterin), und drücken Sie leicht nach unten, um es in der Agar-Oberfläche einbinden. </li><li> Wählen L4 Bühne oder jungen erwachsenen Würmer auf eine Agarplatte mit einigen NGM-Puffer (0,3% NaCl, 1 mM CaCl 2, 1 mM MgSO 4, 25 mM Kaliumphosphatpuffer) gefüllt, um sie von Speiseresten zu waschen. Lassen Sie die Würmer schwimmen für ein paar Minuten. </li><li> Vorsichtig eine einzige Schnecke auf das Tracking Platte nahe der Mitte des Rings. Und legen Sie dann die Platte auf dem Wurm-Tracker. </li></ol> 3. Worm-Tracking <ol><li> Führen Sie das LabVIEW-Programm und wählen Sie Optionen, wenn nötig (Speicherort für Bilder, Arten von Abbildungen, Maße, Kamera-Einstellungen). </li><li> Mit dem Joystick das Mikroskop bis ein Bild des Wurms ist im Sichtfeld (Computer-Bildschirm). Drücken Sie auf &quot;Track&quot;, um die Tracking-Programm engagieren. </li><li> Das Computerprogramm misst direkt die Bewegungen eines binären gefilterten Bilder wie gezeigt und können Messungen über dieses Bild in Echtzeit zu machen </li><li> Achterner Verfolgen einer Rekonstruktion der globalen Bewegungsbahn aus den Schrittmotor Bewegungen ausgeführt werden, während die lokalen Formänderungen der Schnecke im Detail gesehen werden kann. </li></ol> 4. Data Analysis <ol><li> Führen Skelettieren script (MATLAB) des Wurms Formen parametrieren. (Abbildung 2) </li><li> Berechnen Eigenmoden der skelettierten Daten. (Abbildung 3,4) </li><li> Zeigen Abbildung 5. Lesen Figur Legende oder repräsentative Ergebnisse. </li></ol>

<ol>
	<li>Brenner, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+genetics+of+Caenorhabditis+elegans.">The genetics of Caenorhabditis elegans.</a> Genetics. 77 (1), 71-79 (1974).</li><li>de Bono, M., Maricq, A. V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Neuronal+substrates+of+complex+behaviors+in+C.+elegans.">Neuronal substrates of complex behaviors in C. elegans.</a> Annu. Rev. Neurosci. (28), 451-501 (2005).</li><li>Pierce-Shimomura, J. T., Morse, T. M., Lockery, S. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+fundamental+role+of+pirouettes+in+Caenorhabditis+elegans+chemotaxis.">The fundamental role of pirouettes in Caenorhabditis elegans chemotaxis.</a> J. Neurosci. 19 (21), 9557-9569 (1999).</li><li>Gray, J. M., Hill, J. J., Bargmann, C. I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+circuit+for+navigation+in+Caenorhabditis+elegans.">A circuit for navigation in Caenorhabditis elegans.</a> Proc. Natl. Acad. Sci. U.S.A. 102 (9), 3184-3191 (2005).</li><li>Baek, J. H., Cosman, P., Feng, Z., Silver, J., Schafer, W. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Using+machine+vision+to+analyze+and+classify+Caenorhabditis+elegans+behavioral+phenotypes+quantitatively.">Using machine vision to analyze and classify Caenorhabditis elegans behavioral phenotypes quantitatively.</a> J. Neurosci. Methods. 118 (1), 9-21 (2002).</li><li>Stephens, G. J., Johnson-Kerner, B., Bialek, W., Ryu, W. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dimensionality+and+Dynamics+in+the+Behavior+of+C.+elegans.">Dimensionality and Dynamics in the Behavior of C. elegans.</a> PLoS Comput. Biol. 4 (1), e1000028 (2008).</li><li>Stephens, G. J., Johnson-Kerner, B., Bialek, W., Ryu, W. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=From+modes+to+movement+in+the+behavior+of+C.+elegans.">From modes to movement in the behavior of C. elegans.</a> PLoS One. 5 (11), e13914 (2010).</li><li>Feng, Z., Cronin, C. J., Wittig, J. H., Sternberg, P. W., Schafer, W. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+imaging+system+for+standardized+quantitative+analysis+of+C.+elegans+behavior.">An imaging system for standardized quantitative analysis of C. elegans behavior.</a> BMC Bioinformatics. (5), 115 (2004).</li><li>Ramot, D., Johnson, B. E., Berry, T. L., Carnell, L., Goodman, M. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Parallel+Worm+Tracker:+A+Platform+for+Measuring+Average+Speed+and+Drug-Induced+Paralysis+in+Nematodes.">The Parallel Worm Tracker: A Platform for Measuring Average Speed and Drug-Induced Paralysis in Nematodes.</a> PLoS One. 3 (5), e2208 (2008).</li><li>Swierczek, N. A., Giles, A. C., Rankin, C. H., Kerr, 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=High-throughput+behavioral+analysis+in+C.+elegans.">High-throughput behavioral analysis in C. elegans.</a> Nat. Methods. 8 (7), 592-598 (2011).</li><li>Leifer, A. M., Fang-Yen, C., Gershow, M., Alkema, M. J., Samuel, A. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Optogenetic+manipulation+of+neural+activity+in+freely+moving+Caenorhabditis+elegans.">Optogenetic manipulation of neural activity in freely moving Caenorhabditis elegans.</a> Nat. Methods. 8 (2), 147-152 (2011).</li><li>Stirman, J. N., Crane, M. M., Husson, S. J., Wabnig, S., Schultheis, C., Gottschalk, A., Lu, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Real-time+multimodal+optical+control+of+neurons+and+muscles+in+freely+behaving+Caenorhabditis+elegans.">Real-time multimodal optical control of neurons and muscles in freely behaving Caenorhabditis elegans.</a> Nat. Methods. 8 (2), 153-158 (2011).</li><li>Ben Arous, J., Tanizawa, Y., Rabinowitch, I., Chatenay, D., Schafer, W. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Automated+imaging+of+neuronal+activity+in+freely+behaving+Caenorhabditis+elegans.">Automated imaging of neuronal activity in freely behaving Caenorhabditis elegans.</a> J Neurosci Methods. 187 (2), 229-234 (2010).</li><li>Wittenburg, N., Baumeister, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Thermal+avoidance+in+Caenorhabditis+elegans:+an+approach+to+the+study+of+nociception.">Thermal avoidance in Caenorhabditis elegans: an approach to the study of nociception.</a> Proc. Natl. Acad. Sci. U.S.A. 96 (18), 10477-10482 (1999).</li></ol>

Keine Interessenskonflikte erklärt.

Die Studie der Fortbewegung und natürliches Verhalten erfordert nicht-invasive Tracking-Techniken in den Partnerländern mit Datenreduktion Techniken. Hier haben wir eine einfache gezeigt, dass Tracking-System, das detaillierte Bilder von C. Datensätze verwenden elegans Verhalten, wie es auf der Oberfläche einer Agarplatte kriecht. Die Menge der Informationen in diesen Bildern enthalten ist riesig und High-dimensional, und so haben wir auch Methoden, um die Dimensionalität der Daten in nur vier gru...

<table border="1"><tbody><tr><td> Name des Teils </td><td> Firma </td><td> Katalog-Nummer </td><td> Kommentare (optional) </td></tr><tr><td> CCD-Kamera </td><td> Basler </td><td> A601f </td><td></td></tr><tr><td> Objektiv </td><td> Edmund Optics </td><td> MMS-Serie </td><td></td></tr><tr><td> Fiber Beleuchtung </td><td> Dolan Jenner </td><td> DC-950H </td><td></td></tr><tr><td> Übersetzung der Bühne </td><td> Deltron </td><td> LS3-4 </td><td></td></tr><tr><td> Stepper Motor </td><td> US Digital </td><td> MS23C </td><td></td></tr><tr><td> Schrittmotorantrieb </td><td> Gecko </td><td> G201 </td><td></td></tr><tr><td> Schrittmotorsteuerung </td><td> SimpleStep </td><td> SSXYZ </td><td></td></tr><tr><td></td><td></td><td></td><td> Alle Programmcode vorhanden ist. Bitte senden Sie eine Anfrage E-Mail an den entsprechenden Autor. </td></tr></tbody></table>

c. elegans tracking and behavioral measurement

Wir haben Instrumente, Bildverarbeitung und Datenanalyse-Techniken entwickelt, um die motorischen Verhalten von C. Quantifizierung elegans, wie es auf der Oberfläche einer Agarplatte kriecht. Für die Untersuchung der genetischen, biochemischen und neuronalen Grundlagen von Verhalten, C. elegans ist ein idealer Organismus, da sie genetisch gefügig, zugänglich Mikroskopie ist, und zeigt eine Reihe von komplexen Verhaltensweisen, einschließlich Taxis, Lernen und soziale Interaktion 1,2. Verhaltensanalyse auf das Verfolgen der Bewegungen der Würmer wie sie kriechen auf Agarplatten Basis haben sich als besonders nützlich bei der Untersuchung von sensorischen Verhalten 3, Fortbewegung 4 und 5 allgemein Mutations Phänotypisierung. Unser System funktioniert, indem die Kamera und Beleuchtungssystem die Würmer kriecht auf einer stationären Agarplatte, die keine mechanischen Reiz auf die Schnecke übertragen wird gewährleistet. Unser Tracking-System ist einfach zu bedienen und enthält eine semi-automatische Kalibrierung. Ein challenge aller Video-Tracking-Systeme ist, dass es eine enorme Menge an Daten, die intrinsisch hohe Dimensionsstabilität ist, erzeugt. Unsere Bildverarbeitung und Datenanalyse-Programme befassen sich mit dieser Herausforderung, indem die Würmer Form in einer Reihe von unabhängigen Komponenten, die umfassend rekonstruieren die Würmer Verhalten als Funktion von nur 3-4 Abmessungen 6,7. Als ein Beispiel für den Prozess gezeigt, dass die Schnecke und Auswurf aus deren Umkehrung Zustand in einer Phase spezifischen Weise.

Beispiel: bei der Futtersuche, C. elegans Übergänge von vorwärts auf rückwärts Bewegung, oft Durchführung einer Neuorientierung (omega Umdrehung) vor der Rückkehr in die Vorwärtsbewegung Zustand. Quantifizierung dieser Übergang ist für das Verständnis der Nahrungssuche Bewegungsmuster und auch in der Wurm-Motorsteuerung wichtig. Die Befugnis zur subtilen Details der Fortbewegung Verhalten zeigen, zu sehen mit unseren Tracker-Gerät werden. Als Beispiel betrachten wir die ...

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C. elegans Tracking and Behavioral Measurement

Wir haben ein Video-Rate Tracking Mikroskop-System aufzeichnen und quantifizieren können entwickelt<em&gt; C. elegans</em&gt; Verhalten bei hoher Auflösung und hohen Geschwindigkeiten. Wir haben auch Rechenverfahren, um die Dimensionalität der Schnecke Bilder auf einen grundlegenden Satz von Messungen, die vollständig beschreiben die Form der Schnecke, entwickelt.

C. elegans Tracking und Behavioral Measurement

We have developed instrumentation, image processing, and data analysis techniques to quantify the locomotory behavior of C. elegans as it crawls on the ...

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Research

JoVE Journal

Neuroscience

C. elegans Tracking and Behavioral Measurement

18.9K Aufrufe.  University of Toronto. Wir haben ein Video-Rate Tracking Mikroskop-System aufzeichnen und quantifizieren können entwickelt C. elegans Verhalten bei hoher Auflösung und hohen Geschwindigkeiten. Wir haben auch Rechenverfahren, um die Dimensionalität der Schnecke Bilder auf einen grundlegenden Satz von Messungen, die vollständig beschreiben die Form der Schnecke, entwickelt.

Serie: C. elegans Tracking and Behavioral Measurement

Assaying &beta;-amyloid Toxicity using a Transgenic C. elegans Model

Accumulation of the &beta;-amyloid peptide (A&beta;) is generally believed to be central to the induction of Alzheimer's disease, but the relevant mechanism(s) of toxicity are still unclear. A&beta; is also deposited intramuscularly in Inclusion Body Myositis, a severe human myopathy. The intensely studied nematode worm Caenorhabditis elegans can be transgenically engineered to express human A&beta;. Depending on the tissue or timing of A&beta; expression, transgenic worms can have readily measurable phenotypes that serve as a read-out of A&beta; toxicity. For example, transgenic worms with pan-neuronal A&beta; expression have defects is associative learning (Dosanjh et al. 2009), while transgenic worms with constitutive muscle-specific expression show a progressive, age-dependent paralysis phenotype (Link, 1995; Cohen et al. 2006). One particularly useful C. elegans model employs a temperature-sensitive mutation in the mRNA surveillance system to engineer temperature-inducible muscle expression of an A&beta; transgene, resulting in a reproducible paralysis phenotype upon temperature upshift (Link et al. 2003). Treatments that counter A&beta; toxicity in this model [e.g., expression of a protective transgene (Hassan et al. 2009) or exposure to Ginkgo biloba extracts (Wu et al. 2006)] reproducibly alter the rate of paralysis induced by temperature upshift of these transgenic worms. Here we describe our protocol for measuring the rate of paralysis in this transgenic C. elegans model, with particular attention to experimental variables that can influence this measurement.

Assaying &amp;#946;-amyloid Toxicity using a Transgenic C. elegans Model

The intensely studied nematode worm Caenorhabditis elegans can be transgenically engineered to express the human &beta;-amyloid peptide (A&beta;). Induced expression of A&beta; in C. elegans muscle leads to a rapid, reproducible paralysis phenotype that can be used to monitor treatments that modulate A&beta; toxicity.

Assaying β-Amyloid-Toxizität mit Hilfe eines transgenen C. elegans Modell

Accumulation of the &beta;-amyloid peptide (A&beta;) is generally believed to be central to the induction of Alzheimer's disease, but the relevant ...

Forschung

Neurowissenschaften

C. elegans Positive Butanone Learning, Short-term, and Long-term Associative Memory Assays

The memory of experiences and learned information is critical for organisms to make choices that aid their survival. C. elegans navigates its environment through neuron-specific detection of food and chemical odors1, 2, and can associate nutritive states with chemical odors3, temperature4, and the pathogenicity of a food source5.
Here, we describe assays of C. elegans associative learning and short- and long-term associative memory. We modified an aversive olfactory learning paradigm6 to instead produce a positive response; the assay involves starving ~400 worms, then feeding the worms in the presence of the AWC neuron-sensed volatile chemoattractant butanone at a concentration that elicits a low chemotactic index (similar to Toroyama et al.7). A standard population chemotaxis assay1 tests the worms' attraction to the odorant immediately or minutes to hours after conditioning.
After conditioning, wild-type animals' chemotaxis to butanone increases ~0.6 Chemotaxis Index units, its "Learning Index". Associative learning is dependent on the presence of both food and butanone during training. Pairing food and butanone for a single conditioning period ("massed training") produces short-term associative memory that lasts ~2 hours. Multiple conditioning periods with rest periods between ("spaced training") yields long-term associative memory (&lt;40 hours), and is dependent on the cAMP Response Element Binding protein (CREB),6 a transcription factor required for long-term memory across species.8
Our protocol also includes image analysis methods for quick and accurate determination of chemotaxis indices. High-contrast images of animals on chemotaxis assay plates are captured and analyzed by worm counting software in MatLab. The software corrects for uneven background using a morphological tophat transformation.9 Otsu's method is then used to determine a threshold to separate worms from the background.10 Very small particles are removed automatically and larger non-worm regions (plate edges or agar punches) are removed by manual selection. The software then estimates the size of single worm by ignoring regions that are above a specified maximum size and taking the median size of the remaining regions. The number of worms is then estimated by dividing the total area identified as occupied by worms by the estimated size of a single worm.
We have found that learning and short- and long-term memory can be distinguished, and that these processes share similar key molecules with higher organisms.6,8 Our assays can quickly test novel candidate genes or molecules that affect learning and short- or long-term memory in C. elegans that are relevant across species.

C. elegans Positive Butanone Learning, Short-term, and Long-term Associative Memory Assays

Here we describe methods to test C. elegans associative learning and short- and long-term associative memory. These population assays employ the worms abilities to chemotax toward volatile odorants, and form positive associations upon pairing food with the chemoattractant butanone. Increasing the number of conditioning periods induces long-term memory.

C. elegans Positive Butanone Learning, kurzfristige und langfristige Assoziative Speicher Assays

The memory of experiences and learned information is critical for organisms to make choices that aid their survival. C. elegans navigates its environment ...

In vivo Laser Axotomy in C. elegans

Neurons communicate with other cells via axons and dendrites, slender membrane extensions that contain pre- or post-synaptic specializations. If a neuron is damaged by injury or disease, it may regenerate. Cell-intrinsic and extrinsic factors influence the ability of a neuron to regenerate and restore function. Recently, the nematode C. elegans has emerged as an excellent model organism to identify genes and signaling pathways that influence the regeneration of neurons1-6. The main way to initiate neuronal regeneration in C. elegans is laser-mediated cutting, or axotomy. During axotomy, a fluorescently-labeled neuronal process is severed using high-energy pulses. Initially, neuronal regeneration in C. elegans was examined using an amplified femtosecond laser5. However, subsequent regeneration studies have shown that a conventional pulsed laser can be used to accurately sever neurons in vivo and elicit a similar regenerative response1,3,7.
We present a protocol for performing in vivo laser axotomy in the worm using a MicroPoint pulsed laser, a turnkey system that is readily available and that has been widely used for targeted cell ablation. We describe aligning the laser, mounting the worms, cutting specific neurons, and assessing subsequent regeneration. The system provides the ability to cut large numbers of neurons in multiple worms during one experiment. Thus, laser axotomy as described herein is an efficient system for initiating and analyzing the process of regeneration.

In vivo Laser Axotomy in C. elegans

A protocol to cut neurons in C. elegans with a MicroPoint pulsed laser is presented. We describe setting up the system, immobilizing worms, and severing labeled neurons. Advantages include a relatively low-cost system and the ability to sever neuronal processes or ablate cells in vivo.

In-vivo-Laser Axotomie in C. elegans

Neurons communicate with other cells via axons and dendrites, slender membrane extensions that contain pre- or post-synaptic specializations. If a neuron ...

Automated Quantification of Synaptic Fluorescence in C. elegans

Synapse strength refers to the amplitude of postsynaptic responses to presynaptic neurotransmitter release events, and has a major impact on overall neural circuit function. Synapse strength critically depends on the abundance of neurotransmitter receptors clustered at synaptic sites on the postsynaptic membrane. Receptor levels are established developmentally, and can be altered by receptor trafficking between surface-localized, subsynaptic, and intracellular pools, representing important mechanisms of synaptic plasticity and neuromodulation. Rigorous methods to quantify synaptically-localized neurotransmitter receptor abundance are essential to study synaptic development and plasticity. Fluorescence microscopy is an optimal approach because it preserves spatial information, distinguishing synaptic from non-synaptic pools, and discriminating among receptor populations localized to different types of synapses. The genetic model organism Caenorhabditis elegans is particularly well suited for these studies due to the small size and relative simplicity of its nervous system, its transparency, and the availability of powerful genetic techniques, allowing examination of native synapses in intact animals.
Here we present a method for quantifying fluorescently-labeled synaptic neurotransmitter receptors in C. elegans. Its key feature is the automated identification and analysis of individual synapses in three dimensions in multi-plane confocal microscope output files, tabulating position, volume, fluorescence intensity, and total fluorescence for each synapse. This approach has two principal advantages over manual analysis of z-plane projections of confocal data. First, because every plane of the confocal data set is included, no data are lost through z-plane projection, typically based on pixel intensity averages or maxima. Second, identification of synapses is automated, but can be inspected by the experimenter as the data analysis proceeds, allowing fast and accurate extraction of data from large numbers of synapses. Hundreds to thousands of synapses per sample can easily be obtained, producing large data sets to maximize statistical power. Considerations for preparing C. elegans for analysis, and performing confocal imaging to minimize variability between animals within treatment groups are also discussed. Although developed to analyze C. elegans postsynaptic receptors, this method is generally useful for any type of synaptically-localized protein, or indeed, any fluorescence signal that is localized to discrete clusters, puncta, or organelles.
The procedure is performed in three steps: 1) preparation of samples, 2) confocal imaging, and 3) image analysis. Steps 1 and 2 are specific to C. elegans, while step 3 is generally applicable to any punctate fluorescence signal in confocal micrographs.

Automated Quantification of Synaptic Fluorescence in C. elegans

The abundance of neurotransmitter receptors clustered at synapses strongly influences synaptic strength. This method quantifies fluorescently-labeled neurotransmitter receptors in three dimensions with single-synapse resolution in C. elegans, allowing hundreds of synapses to be rapidly characterized within a single sample without distortions introduced by z-plane projection.

Automatisierte Quantifizierung der Fluoreszenz-in Synaptic<em&gt; C elegans</em

Synapse strength refers to the amplitude of postsynaptic responses to presynaptic neurotransmitter release events, and has a major impact on overall ...

A Molecular Readout of Long-term Olfactory Adaptation in C. elegans

During sustained stimulation most sensory neurons will adapt their response by decreasing their sensitivity to the signal. The adaptation response helps shape attention and also protects cells from over-stimulation. Adaptation within the olfactory circuit of C. elegans was first described by Colbert and Bargmann1,2. Here, the authors defined parameters of the olfactory adaptation paradigm, which they used to design a genetic screen to isolate mutants defective in their ability to adapt to volatile odors sensed by the Amphid Wing cells type C (AWC) sensory neurons. When wildtype C. elegans animals are exposed to an attractive AWC-sensed odor3 for 30 min they will adapt their responsiveness to the odor and will then ignore the adapting odor in a chemotaxis behavioral assay for ~1 hr. When wildtype C. elegans animals are exposed to an attractive AWC-sensed odor for ~1 hr they will then ignore the adapting odor in a chemotaxis behavioral assay for ~3 hr. These two phases of olfactory adaptation in C. elegans were described as short-term olfactory adaptation (induced after 30 min odor exposure), and long-term olfactory adaptation (induced after 60 min odor exposure). Later work from L'Etoile et al.,4 uncovered a Protein Kinase G (PKG) called EGL-4 that is required for both the short-term and long-term olfactory adaptation in AWC neurons. The EGL-4 protein contains a nuclear localization sequence that is necessary for long-term olfactory adaptation responses but dispensable for short-term olfactory adaptation responses in the AWC4. By tagging EGL-4 with a green fluorescent protein, it was possible to visualize the localization of EGL-4 in the AWC during prolonged odor exposure. Using this fully functional GFP-tagged EGL-4 (GFP::EGL-4) molecule we have been able to develop a molecular readout of long-term olfactory adaptation in the AWC5. Using this molecular readout of olfactory adaptation we have been able to perform both forward and reverse genetic screens to identify mutant animals that exhibit defective subcellular localization patterns of GFP::EGL-4 in the AWC6,7. Here we describe: 1) the construction of GFP::EGL-4 expressing animals; 2) the protocol for cultivation of animals for long-term odor-induced nuclear translocation assays; and 3) the scoring of the long-term odor-induced nuclear translocation event and recovery (re-sensitization) from the nuclear GFP::EGL-4 state.

A Molecular Readout of Long-term Olfactory Adaptation in C. elegans

Here we describe a molecular readout of long-term olfactory adaptation in Caenorhabditis elegans. The Protein Kinase G, EGL-4, is necessary for stable adaptation responses in the primary sensory neuron pair called AWC. During prolonged odor exposure EGL-4 translocates from the cytosol to nucleus of the AWC.

A Molecular Auslesen Langfristige Olfactory Anpassung in<em&gt; C. elegans</em

During sustained stimulation most sensory neurons will adapt their response by decreasing their sensitivity to the signal. The adaptation response helps ...

Hippocampal Insulin Microinjection and In vivo Microdialysis During Spatial Memory Testing

Glucose metabolism is a useful marker for local neural activity, forming the basis of methods such as 2-deoxyglucose and functional magnetic resonance imaging. However, use of such methods in animal models requires anesthesia and hence both alters the brain state and prevents behavioral measures. An alternative method is the use of in vivo microdialysis to take continuous measurement of brain extracellular fluid concentrations of glucose, lactate, and related metabolites in awake, unrestrained animals. This technique is especially useful when combined with tasks designed to rely on specific brain regions and/or acute pharmacological manipulation; for example, hippocampal measurements during a spatial working memory task (spontaneous alternation) show a dip in extracellular glucose and rise in lactate that are suggestive of enhanced glycolysis1-3,4-5, and intrahippocampal insulin administration both improves memory and increases hippocampal glycolysis6. Substances such as insulin can be delivered to the hippocampus via the same microdialysis probe used to measure metabolites. The use of spontaneous alternation as a measure of hippocampal function is designed to avoid any confound from stressful motivators (e.g. footshock), restraint, or rewards (e.g. food), all of which can alter both task performance and metabolism; this task also provides a measure of motor activity that permits control for nonspecific effects of treatment. Combined, these methods permit direct measurement of the neurochemical and metabolic variables regulating behavior.

Hippocampal Insulin Microinjection and In vivo Microdialysis During Spatial Memory Testing

Modulation of hippocampally-dependent spatial working memory by direct intrahippocampal microinjection, accompanied and followed by in vivo microdialysis for metabolites in conscious, behaving animals.

Hippocampus Insulin Mikroinjektion und<em&gt; In vivo</em&gt; Microdialysis Während Spatial Memory Testing

Glucose metabolism is a useful marker for local neural activity, forming the basis of methods such as 2-deoxyglucose and functional magnetic resonance ...

In vivo Neuronal Calcium Imaging in C. elegans

The nematode worm C. elegans is an ideal model organism for relatively simple, low cost neuronal imaging in vivo. Its small transparent body and simple, well-characterized nervous system allows identification and fluorescence imaging of any neuron within the intact animal. Simple immobilization techniques with minimal impact on the animal's physiology allow extended time-lapse imaging. The development of genetically-encoded calcium sensitive fluorophores such as cameleon 1 and GCaMP 2 allow in vivo imaging of neuronal calcium relating both cell physiology and neuronal activity. Numerous transgenic strains expressing these fluorophores in specific neurons are readily available or can be constructed using well-established techniques. Here, we describe detailed procedures for measuring calcium dynamics within a single neuron in vivo using both GCaMP and cameleon. We discuss advantages and disadvantages of both as well as various methods of sample preparation (animal immobilization) and image analysis. Finally, we present results from two experiments: 1) Using GCaMP to measure the sensory response of a specific neuron to an external electrical field and 2) Using cameleon to measure the physiological calcium response of a neuron to traumatic laser damage. Calcium imaging techniques such as these are used extensively in C. elegans and have been extended to measurements in freely moving animals, multiple neurons simultaneously and comparison across genetic backgrounds. C. elegans presents a robust and flexible system for in vivo neuronal imaging with advantages over other model systems in technical simplicity and cost.

In vivo Neuronal Calcium Imaging in C. elegans

With its small transparent body, well-documented neuroanatomy and a host of amenable genetic techniques and reagents, C. elegans makes an ideal model organism for in vivo neuronal imaging using relatively simple, low-cost techniques. Here we describe single neuron imaging within intact adult animals using genetically encoded fluorescent calcium indicators.

In vivo Neuronale Calcium Imaging in C. elegans

The nematode worm C. elegans is an ideal model organism  for relatively simple, low cost neuronal imaging in vivo. Its small transparent body and simple, ...

Long-term Behavioral Tracking of Freely Swimming Weakly Electric Fish

Long-term behavioral tracking can capture and quantify natural animal behaviors, including those occurring infrequently. Behaviors such as exploration and social interactions can be best studied by observing unrestrained, freely behaving animals. Weakly electric fish (WEF) display readily observable exploratory and social behaviors by emitting electric organ discharge (EOD). Here, we describe three effective techniques to synchronously measure the EOD, body position, and posture of a free-swimming WEF for an extended period of time. First, we describe the construction of an experimental tank inside of an isolation chamber designed to block external sources of sensory stimuli such as light, sound, and vibration. The aquarium was partitioned to accommodate four test specimens, and automated gates remotely control the animals&#39; access to the central arena. Second, we describe a precise and reliable real-time EOD timing measurement method from freely swimming WEF. Signal distortions caused by the animal&#39;s body movements are corrected by spatial averaging and temporal processing stages. Third, we describe an underwater near-infrared imaging setup to observe unperturbed nocturnal animal behaviors. Infrared light pulses were used to synchronize the timing between the video and the physiological signal over a long recording duration. Our automated tracking software measures the animal&#39;s body position and posture reliably in an aquatic scene. In combination, these techniques enable long term observation of spontaneous behavior of freely swimming weakly electric fish in a reliable and precise manner. We believe our method can be similarly applied to the study of other aquatic animals by relating their physiological signals with exploratory or social behaviors.

We describe a set of techniques for studying spontaneous behavior of freely swimming weakly electric fish over an extended period of time, by synchronously measuring the animal&#39;s electric organ discharge timing, body position and posture both accurately and reliably in a specially designed aquarium tank inside a sensory isolation chamber.

Langfristige Verhaltens Verfolgung von Frei Schwimmen Schwach elektrische Fische

Long-term behavioral tracking can capture and quantify natural animal behaviors, including those occurring infrequently. Behaviors such as exploration and ...

Visualizing Neuroblast Cytokinesis During C. elegans Embryogenesis

This protocol describes the use of fluorescence microscopy to image dividing cells within developing Caenorhabditis elegans embryos. In particular, this protocol focuses on how to image dividing neuroblasts, which are found underneath the epidermal cells and may be important for epidermal morphogenesis. Tissue formation is crucial for metazoan development&#160;and relies on external cues from neighboring tissues. C. elegans is an excellent model organism to study tissue morphogenesis in vivo due to its transparency and simple organization, making its tissues easy to study via microscopy. Ventral enclosure is the process where the ventral surface of the embryo is covered by a single layer of epithelial cells. This event is thought to be facilitated by the underlying neuroblasts, which provide chemical guidance cues to mediate migration of the overlying epithelial cells. However, the neuroblasts are highly proliferative and also may act as a mechanical substrate for the ventral epidermal cells. Studies using this experimental protocol could uncover the importance of intercellular communication during tissue formation, and could be used to reveal the roles of genes involved in cell division within developing tissues.

Visualizing Neuroblast Cytokinesis During C. elegans Embryogenesis

This protocol describes how to image dividing cells within a tissue in Caenorhabditis elegans embryos. While several protocols describe how to image cell division in the early embryo, this protocol describes how to image cell division within a developing tissue during mid late embryogenesis.

Visualisierung Neuroblast Cytokinesis Während<em&gt; C. elegans</em&gt; Embryogenese

This protocol describes the use of fluorescence microscopy to image dividing cells within developing Caenorhabditis elegans embryos. In particular, this ...

In Vivo Imaging of Dauer-specific Neuronal Remodeling in C. elegans

The mechanisms controlling stress-induced phenotypic plasticity in animals are frequently complex and difficult to study in vivo. A classic example of stress-induced plasticity is the dauer stage of C. elegans. Dauers are an alternative developmental larval stage formed under conditions of low concentrations of bacterial food and high concentrations of a dauer pheromone. Dauers display extensive developmental and behavioral plasticity. For example, a set of four inner-labial quadrant (IL2Q) neurons undergo extensive reversible remodeling during dauer formation. Utilizing the well-known environmental pathways regulating dauer entry, a previously established method for the production of crude dauer pheromone from large-scale liquid nematode cultures is demonstrated. With this method, a concentration of 50,000 - 75,000 nematodes/ml of liquid culture is sufficient to produce a highly potent crude dauer pheromone. The crude pheromone potency is determined by a dose-response bioassay. Finally, the methods used for in vivo time-lapse imaging of the IL2Qs during dauer formation are described.

In Vivo Imaging of Dauer-specific Neuronal Remodeling in C. elegans

Following exposure to specific environmental stressors, the nematode Caenorhabditis elegans undergoes extensive phenotypic plasticity to enter into a stress-resistant &#8216;dauer&#8217; juvenile stage. We present methods for the controlled induction and imaging of neuroplasticity during dauer.

In-vivo-Imaging von Dauer-spezifische neuronale Remodeling in C. elegans

The mechanisms controlling stress-induced phenotypic plasticity in animals are frequently complex and difficult to study in vivo. A classic example of ...