This work is supported by a Canadian Health Research Institute (CIHR) Team Grant to Dr. Bolduc (co-PI) and Dr. Guy Rouleau (PI). We would like to thank Dr. Oksana Suchowersky, Dr. Kathryn Todd, the members of the University of Alberta fly club and Dr. Clayton Dickson for help in development of the method and statistical analysis.

Forschung an Drosophila melanogaster wurde in Übereinstimmung mit der Universität Forschungs Richtlinien Albertas. 1. Fly-Sammlung <ol><li> Sammeln Sie 20 Fliegen mit CO 2 (g) Betäubung und in eine 25 mm x 95 mm Sammelgefäß haltige Speisen. </li><li> Shop Stechflaschen mit Fliegen horizontal zu vermeiden Trapping Fliegen in allen Flüssigkeiten, die in den Boden anreichern kann das Fläschchen. </li><li> Entfernt inkubiere für mindestens 21 Stunden bei 22 ° C bei 45% Luftfeuchtigkeit in einem Brutschrank für ca. 15 Stunden. Stellen Sie den Inkubator mit einem 12 Stunden Licht: Dunkel-Zyklus. </li></ol> 2. Climbing Assay <ol><li> Am nächsten Morgen, Transfer 20 Fliegen aus einer Ampulle in einen 250-ml-Glasmesszylinder. Markieren Sie die Position des Zylinders, um sie konstant zu halten jeden Tag. Verwenden Sie einen Glaszylinder pro Genotyp um eine Kreuzkontamination zwischen den Genotypen zu verhindern. Waschen Sie am Ende jedes Experiments und rotate sie zwischen den Genotypen. <ol><li> Führen die Versuche im Umgebungslicht (oder rotes Licht, wenn es einen potentiellen Defekt in Vision) bei der Temperatur und Feuchtigkeit von 22 ° C bzw. 40%. Um zirkadianen Rhythmus verwechseln zu vermeiden, führen Sie immer Experimente zur gleichen Tageszeit. </li></ol></li><li> Verschließen Sie die Oberseite des Zylinders mit einer Sperrfolie (Wachsfilm), um das Entweichen jeglicher Fliegen zu verhindern (Abbildung 2). </li><li> Richten Sie die Videokamera auf einem Stativ. Fokus-Kamera auf der Linie 190 ml der 250 ml-Messzylinder (17,5 cm). </li><li> Die Anzahl der toten Fliegen am Boden des Zylinders und in der Lebensmittelfläschchen. Tragen Sie diese Nummer als die Sterblichkeit. </li><li> Sehr leicht den Zylinder gegen einen geschlossenzelligen Schaumpolster wiederholt tippen mit genügend Kraft, um die Fliegen an der inneren Bodenfläche zu verdrängen. Tippen Sie auf 5 bis 10 mal, während mit der anderen Hand auf Rekord auf der Kamera drücken. </li><li> Drücken Sie die &quot;Record&quot; Taste an der Kamera. </li><li> Starten Sie das video Kameraaufnahme und auf den Zylinder, sechs Mal in einem ausgeprägten nicht-rhythmische Muster. </li><li> Leiten jeden Versuch für 2 min von der Zeit die Fliegen letzten abgegriffen und notieren Sie die Anzahl der Fliegen der Höhe von 17,5 cm (190 ml) zu jedem gewählten Zeitpunkt (zu quantifizieren alle 10 sec) überqueren. Hinweis: Das ml Markierung auf dem Zylinder wird von einem Zylinder-Modell zum anderen variieren je nach Durchmesser. Um Fehler zu vermeiden, messen Sie die Höhe an jedem Zylinder verwendet. </li><li> Sobald die Studie beendet ist, entsorgen Sie fliegt in 95% Ethanol. </li><li> Wiederholen Sie die Schritte 2,1-2,9, bis alle Wiederholungen wurden mit frischen Fliegen jedes Mal getestet. Hinweis: Obwohl 5 Wiederholungen können genug mit einer Mutation, die eine starke Wirkung auf die Fortbewegung ist, wird 10 biologischen Replikate von 20 Fliegen (200 entfernt) empfohlen, um kleinere Unterschiede zu erkennen. </li><li> Bei Beendigung des Versuchs, wäscht die Zylinder im Labor Spül- und Trocken O / N wiederverwendet werden. </li></ol> 3. Analyse <ol><li> Analyze Videos von jeder fliegen Studie. Jede 10 Sekunden, notieren Sie die Gesamtzahl der Fliegen, die die Ziellinie passieren. <ol><li> Wenn eine Fliege klettert wieder nach unten und fällt, Datensatz, der als -1 fliegen und zählen Sie die nächste Fliege, um die Ziellinie als die gleiche Anzahl wie die Fliege, die wieder nach unten stieg oder fiel überqueren. Zum Beispiel, wenn der 15. fly unter die Ziellinie, die nächste Fliege, die Linie (16. Fliegen) gilt als der 15. Fliege und nicht der 16. überqueren. </li></ol></li><li> Subtrahiere die Mortalität aus der Gesamtzahl von Fliegen (20), um die Anzahl der Fliegen, die in der Studie bleiben erhalten. Zu jedem Zeitpunkt, erhalten die Fraktion von Fliegen über der Ziellinie. </li><li> Zeichnen Sie jeden Prozentsatz zu jedem Zeitpunkt (siehe Abbildung 3). </li><li> Analysieren Sie die Leistung am 120 s Datenpunkt und führen Sie Student t-Test bei 2 Gruppen vorhanden sind oder ANOVA und einen Post-Test für multiple Vergleiche (mit Bonferroni Modifikation für geplante und ungeplante Tukey für Zusammenarbeitmparisons). Der Kolmogorov-Smirnov-Tests 17 wird auch durchgeführt, um Normalität und gleiche Varianz zu ermitteln, sondern auch, um die Verteilungen des Mutanten-Gruppe an die Steuerung zu vergleichen. </li><li> Um die Daten über Alterung zu präsentieren, zeichnen den Prozentsatz von Fliegen Klettern bei 120 sec mit Fliegen unterschiedlichen Alters (2 Tage, 1 Woche, 2 Wochen), um zu sehen, ob es eine fortschreitende Defizit (Abbildung 4). </li></ol>

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S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Rapid+iterative+negative+geotaxis+(RING):+a+new+method+for+assessing+age-related+locomotor+decline+in+Drosophila.">Rapid iterative negative geotaxis (RING): a new method for assessing age-related locomotor decline in Drosophila.</a> Experimental gerontology. 40, 386-395 (2005).</li><li>Botella, J. A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Drosophila+carbonyl+reductase+sniffer+prevents+oxidative+stress-induced+neurodegeneration.">The Drosophila carbonyl reductase sniffer prevents oxidative stress-induced neurodegeneration.</a> Current biology : CB. 14, 782-786 (2004).</li><li>Feany, M. B., Bender, W. 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The authors have nothing to disclose.

Drosophila hat bereits bewiesen, dass ein ausgezeichnetes Modell der Parkinson-Krankheit 14 und andere neurodegenerative Erkrankungen 1,2 sein. Zusätzlich zu den genetischen Werkzeugen von Drosophila, wird dessen Genom sehr für Gene in neurologischen Erkrankungen beteiligten 19 konserviert. Das Aufkommen der genomweite genetische Screening-Methoden (einschließlich ganze Exoms Sequenzierung) wird sich wahrscheinlich fortsetzen, um eine größere Liste der Kandidatenge...

Verheerenden neurodegenerativen Erkrankungen wie Parkinson-Krankheit, amyotrophe Lateralsklerose und Spastische Paraplegie werden zunehmend anerkannt. Leider sind die meisten dieser neurodegenerativen Erkrankungen noch ohne Behandlungen. Die weit verbreitete klinische Anwendung von genomweiten, unvoreingenommene Gentests wie Voll Exom-Sequenzierung hat zu einer wachsenden Anzahl von Genen geführt, dass in der menschlichen Bewegungsapparates verwickelt. Trotz dieser Fortschritte die pathologische Progression von früh bis spät Bühnen, in weiter Ferne in dieser Erkrankungen. Drosophila stellt ein mit den genetischen Werkzeuge zum Studium Gen Anforderung in einer kontrollierten Art und Weise räumlich und zeitlich. Darüber hinaus hat Drosophila nützlich beim Screening Medikamenten für neurologische Erkrankungen wie der Parkinson-1, Alzheimer-2, geistiger Behinderung und Epilepsie 3,4 5,6 ua bewährt. Unser Ziel war es, eine kostengünstige Entwicklungund zuverlässigen Assay, der Analyse mit hohem Durchsatz, die noch ausreichend empfindlich gegenüber kleinen Änderungen in der Motorleistung zu detektieren würde ermöglichen würde. Es gibt verschiedene Tests verwendet, um die Effekte der genetischen Mutation und / oder Umgebungsbedingung auf Drosophila Kletterverhalten zu quantifizieren. Die meisten der Tests zu profitieren auf die natürliche Tendenz von Fliegen zu klettern, als negative Geotaxis oder Kletter Assay bekannt. Benzer 7 vorgeschlagen 1967, dass der Gegenstrom-Vorrichtung für die Untersuchung der Phototaxis verwendet könnte auch zur Gravitaxis untersuchen. Seitdem haben Ganetzki 8 und viele andere 9 -12 auf der ersten Test gebaut. Das Prinzip ist, um eine bekannte Anzahl der Fliegen in einem Fläschchen zu stellen und tippen Sie auf die Fläschchen kräftig gegen eine harte Oberfläche, wodurch die Fliegen an den Boden des Fläschchens fällt. Da es ein angeborenes Verhalten, werden die Fliegen versuchen, auf der Oberseite des Fläschchens, der Schwerkraft entgegengesetzt zu klettern. Dieser Test ist quantitativ und measures, wie viele Fliegen haben während einer vorgegebenen Zeit an einer Markierung auf dem Fläschchen kletterte. Messung der Geschwindigkeit anstatt der gesamten Anzahl der Fliegen Steigen zu einem verlässlichen Parameter und in Fällen, wo die Anzahl der Fliegen Kriterien nicht signifikant war 13 gezeigt Defekten. Die Steig Assay in der Studie von vielen neurodegenerativen Erkrankungen einschließlich Parkinson-Krankheit 14 bewährt. Allerdings haben wir festgestellt, dass Lok Mängel möglicherweise nicht nachweisbar sein zum Zeitpunkt, wo Neurodegeneration ist bereits in pathologischen Studien 14 zu sehen. Somit kann die Verwendung des herkömmlichen Assay die Fähigkeit, die frühen Stadien der Krankheit zu untersuchen Pathogenese begrenzen. Das Aussehen der Lokomotive Defekte während späteren Phasen der Pathologie kann eine Krankheit, deren Progression zu fortgeschritten für komplette Rettungs reflektieren. Dies wirft ein mögliches Problem mit der Empfindlichkeit des traditionellen Kletter Assay. Der potenzielle Unfähigkeit des tradinalen Klettern Assay zu mild Lokomotive Mängel erkennen kann, um die Höhe, auf die die Fliegen sind erforderlich, um zu klettern zurückzuführen. Die herkömmlichen Assay 15,16 misst die Anzahl der Fliegen, um erfolgreich über eine Höhe von 2 bis 5 cm steigen in 10 bis 20 Sekunden.

<table border="0" cellpadding="0" cellspacing="0">
	<tbody>
		<tr>
			<td>Drosophila stocks</td>
			<td></td>
			<td></td>
			<td>The stocks are selected depending on the experiments. The temperature and humidity in the room and in the incubator must be controled and consistent to avoid flies being too staticky or too wet.</td>
		</tr>
		<tr>
			<td>Video camera</td>
			<td></td>
			<td></td>
			<td>Any digital camcorder will do. Make sure they can focus on close object.</td>
		</tr>
		<tr>
			<td>Graduated cylinder</td>
			<td>Kimble</td>
			<td>20028W</td>
			<td>Different models of graduated cylinder may have different diameter. It is therefore imporant to measure the height.</td>
		</tr>
		<tr>
			<td>computer</td>
			<td></td>
			<td></td>
			<td>Any model will do. We used the computer to monitor the climbing of the flies and record the number of flies at each time point</td>
		</tr>
	</tbody>
</table>

quantitative analysis of climbing defects in a drosophila model of neurodegenerative disorders

Locomotive Mängel von neurodegenerativen Erkrankungen resultiert, kann ein später Beginn Symptom der Krankheit, nach Jahren der subklinischen Degeneration und damit aktuelle therapeutische Behandlungsstrategien sind nicht kurativ. Durch die Verwendung von Voll Exoms Sequenzierung, eine zunehmende Anzahl von Genen identifiziert worden, eine Rolle in menschlichen Fortbewegung spielt. Trotz der Identifizierung dieser Gene, ist es nicht bekannt, wie diese Gene sind entscheidend für die normale Bewegungsfunktion. Daher ist ein zuverlässiger Test, der Modellorganismen verwendet, um die Rolle dieser Gene, um neue Targets von therapeutischem Interesse zu identifizieren aufzuklären, ist mehr denn je erforderlich. Wir haben eine sensibilisierte Version der negativen geotaxis Assay, der zum Nachweis von Mängeln milder früheren ermöglicht, und die Fähigkeit hat, diese Mängel über der Zeit erfasst gestaltet. Der Test wird in einem Glas durchgeführt Meßzylinder, der mit einem Wachsbarriere-Film abgedichtet ist. Durch die Erhöhung der Schwellenabstand um 17,5 c bestiegen werdenm und die Erhöhung der Versuchsdauer bis 2 Minuten haben wir eine größere Empfindlichkeit beim Nachweis von mild Mobilitätsstörungen beobachtet. Der Test wird kostengünstig und erfordert keine umfangreiche Ausbildung zu hoch reproduzierbare Ergebnisse zu erhalten. Dies macht es eine ausgezeichnete Technik für das Screening von Wirkstoffkandidaten in Drosophila-Mutanten mit Bewegungsfehler.

Klettern ist eine starke und reproduzierbare Verhalten. Tatsächlich erreichen einen Tag alt Wildtyp-Fliegen die Zielentfernung Kletterleistung schnell (25-30 sec). Mutierten Fliegen präsentieren ein Leistungsbereich von mild (oder verzögert) die Unfähigkeit, die dem Ziel klettern abzuschließen. Wir veranschaulichen dies hier mit zwei verschiedenen mutierten Allelen. Die erste ist eine schwere Allel des Gens Spastin durch eine vollständige Löschung des Spastin Gen (Spas 5,75) 18 verursacht. In dieser Ze...

Watch this Scientific Journal Video about Quantitative Analysis of Climbing Defects in a Drosophila Model of Neurodegenerative Disorders at JoVE.com

Quantitative Analysis of Climbing Defects in a Drosophila Model of Neurodegenerative Disorders

We present an optimized inexpensive and reliable negative geotaxis assay in Drosophila melanogaster as a model for neurodegenerative disorders. Being more sensitive to mild locomotor defects, this assay will help screen for potential genetic interactions and drug targets.

Quantitative Analyse der Kletter Defekte in einem Drosophila Modell von neurodegenerativen Erkrankungen

Locomotive defects resulting from neurodegenerative disorders can be a late onset symptom of disease, following years of subclinical degeneration, and ...

quantitative-analysis-climbing-defects-drosophila-model

Research

JoVE Journal

Neuroscience

18.3K Aufrufe.  University of Alberta. We present an optimized inexpensive and reliable negative geotaxis assay in Drosophila melanogaster as a model for neurodegenerative disorders. Being more sensitive to mild locomotor defects, this assay will help screen for potential genetic interactions and drug targets. 

Serie: Quantitative Analysis of Climbing Defects in a Drosophila Model of Neurodegenerative Disorders

Ex vivo Culturing of Whole, Developing Drosophila Brains

We describe a method for ex vivo culturing of whole Drosophila brains. This can be used as a counterpoint to chronic genetic manipulations for investigating the cell biology and development of central brain structures by allowing acute pharmacological interventions and live imaging of cellular processes. As an example of the technique, prior work from our lab1 has shown that a previously unrecognized subcellular compartment lies between the axonal and somatodendritic compartments of axons of the Drosophila central brain. The development of this compartment, referred to as the axon initial segment (AIS)2, was shown genetically to depend on the neuron-specific cyclin-dependent kinase, Cdk5. We show here that ex vivo treatment of wild-type Drosophila larval brains with the Cdk5-specific pharmacological inhibitors roscovitine and olomoucine3 causes acute changes in actin organization, and in localization of the cell-surface protein Fasciclin 2, that mimic the changes seen in mutants that lack Cdk5 activity genetically.
A second example of the ex vivo culture technique is provided for remodeling of the connections of embryonic mushroom body (MB) gamma neurons during metamorphosis from larva to adult. The mushroom body is the center of olfactory learning and memory in the fly4, and these gamma neurons prune their axonal and dendritic branches during pupal development and then re-extend branches at a later timepoint to establish the adult innervation pattern5. Pruning of these neurons of the MB has been shown to occur via local degeneration of neurite branches6, by a mechanism that is triggered by ecdysone, a steroid hormone, acting at the ecdysone receptor B17, and that is dependent on the activity of the ubiquitin-proteasome system6. Our method of ex vivo culturing can be used to interrogate further the mechanism of developmental remodeling. We found that in the ex vivo culture setting, gamma neurons of the MB recapitulated the process of developmental pruning with a time course similar to that in vivo. It was essential, however, to wait until 1.5 hours after puparium formation before explanting the tissue in order for the cells to commit irreversibly to metamorphosis; dissection of animals at the onset of pupariation led to little or no metamorphosis in culture. Thus, with appropriate modification, the ex vivo culture approach can be applied to study dynamic as well as steady state aspects of central brain biology.

Ex vivo Culturing of Whole, Developing Drosophila Brains

This article describes a method by which one can mimic in vivo development of the Drosophila mushroom body in an ex vivo culture system.

Ex vivo Kultivierung von Whole, Entwickeln von Drosophila Brains

We describe a method for ex vivo culturing of whole Drosophila brains. This can be used as a counterpoint to chronic genetic manipulations for ...

Forschung

Neurowissenschaften

Assessing Neurodegenerative Phenotypes in Drosophila Dopaminergic Neurons by Climbing Assays and Whole Brain Immunostaining

Drosophila melanogaster is a valuable model organism to study aging and pathological degenerative processes in the nervous system. The advantages of the fly as an experimental system include its genetic tractability, short life span and the possibility to observe and quantitatively analyze complex behaviors. The expression of disease-linked genes in specific neuronal populations of the Drosophila brain, can be used to model human neurodegenerative diseases such as Parkinson's and Alzheimer's 5.
Dopaminergic (DA) neurons are among the most vulnerable neuronal populations in the aging human brain. In Parkinson's disease (PD), the most common neurodegenerative movement disorder, the accelerated loss of DA neurons leads to a progressive and irreversible decline in locomotor function. In addition to age and exposure to environmental toxins, loss of DA neurons is exacerbated by specific mutations in the coding or promoter regions of several genes. The identification of such PD-associated alleles provides the experimental basis for the use of Drosophila as a model to study neurodegeneration of DA neurons in vivo. For example, the expression of the PD-linked human &alpha;-synuclein gene in Drosophila DA neurons recapitulates some features of the human disease, e.g. progressive loss of DA neurons and declining locomotor function 2. Accordingly, this model has been successfully used to identify potential therapeutic targets in PD 8.
Here we describe two assays that have commonly been used to study age-dependent neurodegeneration of DA neurons in Drosophila: a climbing assay based on the startle-induced negative geotaxis response and tyrosine hydroxylase immunostaining of whole adult brain mounts to monitor the number of DA neurons at different ages. In both cases, in vivo expression of UAS transgenes specifically in DA neurons can be achieved by using a tyrosine hydroxylase (TH) promoter-Gal4 driver line 3, 10.

Assessing Neurodegenerative Phenotypes in Drosophila Dopaminergic Neurons by Climbing Assays and Whole Brain Immunostaining

Here we describe two assays that have been established to study age-dependent neurodegeneration of dopaminergic (DA) neurons in Drosophila: the climbing/startle-induced negative geotaxis assay which allows to study the functional effects of DA neurons degeneration and the tyrosine hydroxylase immunostaining which is used to identify and count DA neurons in whole brain mounts.

Beurteilung Neurodegenerative Phänotypen in<em&gt; Drosophila</em&gt; Dopaminergen Neuronen durch Klettern Assays und Whole Brain Immunostaining

Drosophila melanogaster is a valuable model organism to study aging and pathological degenerative processes in the nervous system. The advantages of the ...

Fast Micro-iontophoresis of Glutamate and GABA: A Useful Tool to Investigate Synaptic Integration

One of the fundamental interests in neuroscience is to understand the integration of excitatory and inhibitory inputs along the very complex structure of the dendritic tree, which eventually leads to neuronal output of action potentials at the axon. The influence of diverse spatial and temporal parameters of specific synaptic input on neuronal output is currently under investigation, e.g. the distance-dependent attenuation of dendritic inputs, the location-dependent interaction of spatially segregated inputs, the influence of GABAergig inhibition on excitatory integration, linear and non-linear integration modes, and many more.
With fast micro-iontophoresis of glutamate and GABA it is possible to precisely investigate the spatial and temporal integration of glutamatergic excitation and GABAergic inhibition. Critical technical requirements are either a triggered fluorescent lamp, light-emitting diode (LED), or a two-photon scanning microscope to visualize dendritic branches without introducing significant photo-damage of the tissue. Furthermore, it is very important to have a micro-iontophoresis amplifier that allows for fast capacitance compensation of high resistance pipettes. Another crucial point is that no transmitter is involuntarily released by the pipette during the experiment.
Once established, this technique will give reliable and reproducible signals with a high neurotransmitter and location specificity. Compared to glutamate and GABA uncaging, fast iontophoresis allows using both transmitters at the same time but at very distant locations without limitation to the field of view. There are also advantages compared to focal electrical stimulation of axons: with micro-iontophoresis the location of the input site is definitely known and it is sure that only the neurotransmitter of interest is released. However it has to be considered that with micro-iontophoresis only the postsynapse is activated and presynaptic aspects of neurotransmitter release are not resolved. In this article we demonstrate how to set up micro-iontophoresis in brain slice experiments.

In this article we introduce fast micro-iontophoresis of neurotransmitters as a technique to investigate integration of postsynaptic signals with high spatial and temporal precision.

Schnelle Micro-Iontophorese von Glutamat und GABA: Ein nützliches Tool, um Synaptic Integration Untersuchen

One of the fundamental interests in neuroscience is to understand the integration of excitatory and inhibitory inputs along the very complex structure of ...

High-Resolution Quantitative Immunogold Analysis of Membrane Receptors at Retinal Ribbon Synapses

Retinal ganglion cells (RGCs) receive excitatory glutamatergic input from bipolar cells. Synaptic excitation of RGCs is mediated postsynaptically by NMDA receptors (NMDARs) and AMPA receptors (AMPARs). Physiological data have indicated that glutamate receptors at RGCs are expressed not only in postsynaptic but also in perisynaptic or extrasynaptic membrane compartments. However, precise anatomical locations for glutamate receptors at RGC synapses have not been determined. Although a high-resolution quantitative analysis of glutamate receptors at central synapses is widely employed, this approach has had only limited success in the retina. We developed a postembedding immunogold method for analysis of membrane receptors, making it possible to estimate the number, density and variability of these receptors at retinal ribbon synapses. Here we describe the tools, reagents, and the practical steps that are needed for: 1) successful preparation of retinal fixation, 2) freeze-substitution, 3) postembedding immunogold electron microscope (EM) immunocytochemistry and, 4) quantitative visualization of glutamate receptors at ribbon synapses.

The postembedding immunogold method is one of the most effective ways to provide high-resolution analyses of the subcellular localization of specific molecules. Here we describe a protocol to quantitatively analyze glutamate receptors at retinal ribbon synapses.

Hochauflösende Quantitative Immungold-Analyse von Membranrezeptoren auf der Netzhaut Ribbon Synapsen

Retinal ganglion cells (RGCs) receive excitatory glutamatergic input from bipolar cells. Synaptic excitation of RGCs is mediated postsynaptically by NMDA ...

Analyzing Synaptic Modulation of Drosophila melanogaster Photoreceptors after Exposure to Prolonged Light

The nervous system has the remarkable ability to adapt and respond to various stimuli. This neural adjustment is largely achieved through plasticity at the synaptic level. The Active Zone (AZ) is the region at the presynaptic membrane that mediates neurotransmitter release and is composed of a dense collection of scaffold proteins. AZs of Drosophila melanogaster (Drosophila) photoreceptors undergo molecular remodeling after prolonged exposure to natural ambient light. Thus the level of neuronal activity can rearrange the molecular composition of the AZ and contribute to the regulation of the functional output.
Starting from the light exposure set-up preparation to the immunohistochemistry, this protocol details how to quantify the number, the spatial distribution, and the delocalization level of synaptic molecules at AZs in Drosophila photoreceptors. Using image analysis software, clusters of the GFP-fused AZ component Bruchpilot were identified for each R8 photoreceptor (R8) axon terminal. Detected Bruchpilot spots were automatically assigned to individual R8 axons. To calculate the distribution of spot frequency along the axon, we implemented a customized software plugin. Each axon&#39;s start-point and end-point were manually defined and the position of each Bruchpilot spot was projected onto the connecting line between start and end-point. Besides the number of Bruchpilot clusters, we also quantified the delocalization level of Bruchpilot-GFP within the clusters. These measurements reflect in detail the spatially resolved synaptic dynamics in a single neuron under different environmental conditions to stimuli.

Analyzing Synaptic Modulation of Drosophila melanogaster Photoreceptors after Exposure to Prolonged Light

Here we show how to quantify the number and spatial distribution of synaptic active zones in Drosophila melanogaster&#160;photoreceptors, highlighted with a genetically encoded molecular marker, and their modulation after prolonged exposure to light.

Analyse Synaptische Modulation von<em&gt; Drosophila melanogaster</em&gt; Photorezeptoren nach der Einwirkung von Längerer Licht

The nervous system has the remarkable ability to adapt and respond to various stimuli. This neural adjustment is largely achieved through plasticity at ...

The Use of Trace Eyeblink Classical Conditioning to Assess Hippocampal Dysfunction in a Rat Model of Fetal Alcohol Spectrum Disorders

Neonatal rats were administered a relatively high concentration of ethyl alcohol (11.9% v/v) during postnatal days 4-9, a time when the fetal brain undergoes rapid organizational change and is similar to accelerated brain changes that occur during the third trimester in humans. This model of fetal alcohol spectrum disorders (FASDs) produces severe brain damage, mimicking the amount and pattern of binge-drinking that occurs in some pregnant alcoholic mothers. We describe the use of trace eyeblink classical conditioning (ECC), a higher-order variant of associative learning, to assess long-term hippocampal dysfunction that is typically seen in alcohol-exposed adult offspring. At 90 days of age, rodents were surgically prepared with recording and stimulating electrodes, which measured electromyographic (EMG) blink activity from the left eyelid muscle and delivered mild shock posterior to the left eye, respectively. After a 5 day recovery period, they underwent 6 sessions of trace ECC to determine associative learning differences between alcohol-exposed and control rats. Trace ECC is one of many possible ECC procedures that can be easily modified using the same equipment and software, so that different neural systems can be assessed. ECC procedures in general, can be used as diagnostic tools for detecting neural pathology in different brain systems and different conditions that insult the brain.

Trace eyeblink classical conditioning (ECC) was used to assess hippocampal-dependent associative learning in adult rats that were administered a high concentration (11.9% v/v) of alcohol during early neonatal brain development. In general, ECC procedures are sound diagnostic tools for detecting brain dysfunction across many psychological and biomedical settings.

Die Verwendung von Trace Eyeblink klassische Konditionierung hippocampale Funktionsstörung in einem Rattenmodell der Fetal Alcohol Spectrum Disorders bewerten

Neonatal rats were administered a relatively high concentration of ethyl alcohol (11.9% v/v) during postnatal days 4-9, a time when the fetal brain ...

Assessment of Blood-brain Barrier Permeability by Intravenous Infusion of FITC-labeled Albumin in a Mouse Model of Neurodegenerative Disease

Disruption of blood-brain barrier (BBB) integrity is a common feature for different neurological and neurodegenerative diseases. Although the interplay between perturbed BBB homeostasis and the pathogenesis of brain disorders needs further investigation, the development and validation of a reliable procedure to accurately detect BBB alterations may be crucial and represent a useful tool for potentially predicting disease progression and developing targeted therapeutic strategies.
Here, we present an easy and efficient procedure for evaluating BBB leakage in a neurodegenerative condition like that occurring in a preclinical mouse model of Huntington disease, in which defects in the permeability of BBB are clearly detectable precociously in the disease. Specifically, the high molecular weight fluorescein isothiocyanate labelled (FITC)-albumin, which is able to cross the BBB only when the latter is impaired, is acutely infused into a mouse jugular vein and its distribution in the vascular or parenchymal districts is then determined by fluorescence microscopy.
Accumulation of green fluorescent-albumin in the brain parenchyma functions as an index of aberrant BBB permeability and, when quantitated by using Image J processing software, is reported as Green Fluorescence Intensity.

In this study, we present an easy and efficient procedure for evaluating the disruption of the blood-brain barrier under neurodegenerative conditions. To achieve our objective, we infused high molecular weight fluorescein isothiocyanate labelled (FITC)-albumin into mouse jugular vein and evaluated its leakage into the brain parenchyma by fluorescence microscopy.

Beurteilung der Durchlässigkeit der Blut - Hirn-Schranke durch intravenöse Infusion von FITC-markierte Albumin in einem Mausmodell der Neurodegenerative Erkrankung

Disruption of blood-brain barrier (BBB) integrity is a common feature for different neurological and neurodegenerative diseases. Although the interplay ...

Quantitative Analysis of Neuronal Dendritic Arborization Complexity in Drosophila

Dendrites are the branched projections of a neuron, and dendritic morphology reflects synaptic organization during the development of the nervous system. Drosophila larval neuronal dendritic arborization (da) is an ideal model for studying morphogenesis of neural dendrites and gene function in the development of nervous system. There are four classes of da neurons. Class IV is the most complex with a branching pattern that covers almost the entire area of the larval body wall. We have previously characterized the effect of silencing the Drosophila ortholog of SOX5 on class IV neuronal dendritic arborization complexity (NDAC) using four parameters: the length of dendrites, the surface area of dendrite coverage, the total number of branches, and the branching structure. This protocol presents the workflow of NDAC quantitative analysis, consisting of larval dissection, confocal microscopy, and image analysis procedures using ImageJ software. Further insight into da neuronal development and its underlying mechanisms will improve the understanding of neuronal function and provide clues about the fundamental causes of neurological and neurodevelopmental disorders.

Quantitative Analysis of Neuronal Dendritic Arborization Complexity in Drosophila

This protocol focuses on quantitative analysis of neuronal dendritic arborization complexity (NDAC) in Drosophila, which can be used for studies of dendritic morphogenesis.

Quantitative Analyse der neuronalen dendritischen Arborization Komplexität in Drosophila

Dendrites are the branched projections of a neuron, and dendritic morphology reflects synaptic organization during the development of the nervous system. ...

Quantitative Cell Biology of Neurodegeneration in Drosophila Through Unbiased Analysis of Fluorescently Tagged Proteins Using ImageJ

With the rising prevalence of neurodegenerative diseases, it is increasingly important to understand the underlying pathophysiology that leads to neuronal dysfunction and loss. Fluorescence-based imaging tools and technologies enable unprecedented analysis of subcellular neurobiological processes, yet there is still a need for unbiased, reproducible, and accessible approaches for extracting quantifiable data from imaging studies. We have developed a simple and adaptable workflow to extract quantitative data from fluorescence-based imaging studies using Drosophila models of neurodegeneration. Specifically, we describe an easy-to-follow, semi-automated approach using Fiji/ImageJ to analyze two cellular processes: first, we quantify protein aggregate content and profile in the Drosophila optic lobe using fluorescent-tagged mutant huntingtin proteins; and second, we assess autophagy-lysosome flux in the Drosophila visual system with ratiometric-based quantification of a tandem fluorescent reporter of autophagy. Importantly, the protocol outlined here includes a semi-automated segmentation step to ensure all fluorescent structures are analyzed to minimize selection bias and to increase resolution of subtle comparisons. This approach can be extended for the analysis of other cell biological structures and processes implicated in neurodegeneration, such as proteinaceous puncta (stress granules and synaptic complexes), as well as membrane-bound compartments (mitochondria and membrane trafficking vesicles). This method provides a standardized, yet adaptable reference point for image analysis and quantification, and could facilitate reliability and reproducibility across the field, and ultimately enhance mechanistic understanding of neurodegeneration.

Quantitative Cell Biology of Neurodegeneration in Drosophila Through Unbiased Analysis of Fluorescently Tagged Proteins Using ImageJ

We have developed a simple and adaptable workflow to extract quantitative data from fluorescence-imaging-based cell biological studies of protein aggregation and autophagic flux in the central nervous system of Drosophila models of neurodegeneration.

Quantitative Zellbiologie der Neurodegeneration in Drosophila durch unvoreingenommene Analyse der Gewebekulturen Tagged Proteine mit ImageJ

With the rising prevalence of neurodegenerative diseases, it is increasingly important to understand the underlying pathophysiology that leads to neuronal ...

Isolation of Adult Spinal Cord Nuclei for Massively Parallel Single-nucleus RNA Sequencing

Probing an individual cell&#39;s gene expression enables the identification of cell type and cell state. Single-cell RNA sequencing has emerged as a powerful tool for studying transcriptional profiles of cells, particularly in heterogeneous tissues such as the central nervous system. However, dissociation methods required for single cell sequencing can lead to experimental changes in the gene expression and cell death. Furthermore, these methods are generally restricted to fresh tissue, thus limiting studies on archival and bio-bank material. Single nucleus RNA sequencing (snRNA-Seq) is an appealing alternative for transcriptional studies, given that it accurately identifies cell types, permits the study of tissue that is frozen or difficult to dissociate, and reduces dissociation-induced transcription. Here, we present a high-throughput protocol for rapid isolation of nuclei for downstream snRNA-Seq. This method enables isolation of nuclei from fresh or frozen spinal cord samples and can be combined with two massively parallel droplet encapsulation platforms.

Here, we present a protocol to rapidly isolate high-quality nuclei from the fresh or frozen tissue for downstream massively parallel RNA sequencing. We include detergent-mechanical and hypotonic-mechanical tissue disruption and cell lysis options, both of which can be used for isolation of nuclei.

Isolierung von Erwachsenen Rückenmark Kerne für massiv parallele Single-Kern-RNA-Sequenzierung

Probing an individual cell&#39;s gene expression enables the identification of cell type and cell state. Single-cell RNA sequencing has emerged as a ...