Name: taste preference assay for adult drosophila
Uploaded: 2016-09-08T12:30:00
Description: Watch this Scientific Journal Video about Taste Preference Assay for Adult Drosophila at JoVE.com

We would like to thank members of the Tessier lab for critical reading of this manuscript and helpful suggestions during the preparation of this protocol.

1. Starvation
<ol>
	<li>Prepare fly starvation vials by saturating a cotton ball with 18.2 M&#937; water at the bottom of a standard fly vial. Alternatively, similarly saturate a small strip of filter paper with 18.2 M&#937; water and place at an angle within the vial.</li>
	<li>Collect flies into sets of ~100 animals on a CO2 pad and then add the flies to a prepared vial. 
	Note: Best results are obtained with animals that are less than 5 days old. However, the exact age of the animals can be controlle...

<ol>
	<li>Herrero, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fruit+fly+behavior+in+response+to+chemosensory+signals.">Fruit fly behavior in response to chemosensory signals.</a> Peptides. 38 (2), 228-237 (2012).</li><li>Vosshall, L. B., Stocker, R. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Molecular+architecture+of+smell+and+taste+in+Drosophila.">Molecular architecture of smell and taste in Drosophila.</a> Annu Rev Neurosci. 30, 505-533 (2007).</li><li>Harris, D. T., Kallman, B. R., Mullaney, B. C., Scott, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Representations+of+Taste+Modality+in+the+Drosophila+Brain.">Representations of Taste Modality in the Drosophila Brain.</a> Neuron. 86 (6), 1449-1460 (2015).</li><li>Hong, E. J., Wilson, R. I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Simultaneous+encoding+of+odors+by+channels+with+diverse+sensitivity+to+inhibition.">Simultaneous encoding of odors by channels with diverse sensitivity to inhibition.</a> Neuron. 85 (3), 573-589 (2015).</li><li>Kain, P., Dahanukar, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Secondary+taste+neurons+that+convey+sweet+taste+and+starvation+in+the+Drosophila+brain.">Secondary taste neurons that convey sweet taste and starvation in the Drosophila brain.</a> Neuron. 85 (4), 819-832 (2015).</li><li>Masek, P., Worden, K., Aso, Y., Rubin, G. M., Keene, A. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+dopamine-modulated+neural+circuit+regulating+aversive+taste+memory+in+Drosophila.">A dopamine-modulated neural circuit regulating aversive taste memory in Drosophila.</a> Curr Biol. 25 (11), 1535-1541 (2015).</li><li>Charlu, S., Wisotsky, Z., Medina, A., Dahanukar, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Acid+sensing+by+sweet+and+bitter+taste+neurons+in+Drosophila+melanogaster.">Acid sensing by sweet and bitter taste neurons in Drosophila melanogaster.</a> Nat Commun. 4, 2042 (2013).</li><li>Clyne, P. J., Warr, C. G., Carlson, J. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Candidate+taste+receptors+in+Drosophila.">Candidate taste receptors in Drosophila.</a> Science. 287 (5459), 1830-1834 (2000).</li><li>Scott, K., 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=A+chemosensory+gene+family+encoding+candidate+gustatory+and+olfactory+receptors+in+Drosophila.">A chemosensory gene family encoding candidate gustatory and olfactory receptors in Drosophila.</a> Cell. 104 (5), 661-673 (2001).</li><li>Kim, S. H., 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=Drosophila+TRPA1+channel+mediates+chemical+avoidance+in+gustatory+receptor+neurons.">Drosophila TRPA1 channel mediates chemical avoidance in gustatory receptor neurons.</a> Proc Natl Acad Sci U S A. 107 (18), 8440-8445 (2010).</li><li>Koh, T. W., 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+IR20a+clade+of+ionotropic+receptors+are+candidate+taste+and+pheromone+receptors.">The Drosophila IR20a clade of ionotropic receptors are candidate taste and pheromone receptors.</a> Neuron. 83 (4), 850-865 (2014).</li><li>Zhang, Y. V., Ni, J., Montell, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+molecular+basis+for+attractive+salt-taste+coding+in+Drosophila.">The molecular basis for attractive salt-taste coding in Drosophila.</a> Science. 340 (6138), 1334-1338 (2013).</li><li>Zhang, Y. V., Raghuwanshi, R. P., Shen, W. L., Montell, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Food+experience-induced+taste+desensitization+modulated+by+the+Drosophila+TRPL+channel.">Food experience-induced taste desensitization modulated by the Drosophila TRPL channel.</a> Nat Neurosci. 16 (10), 1468-1476 (2013).</li><li>Liman, E. R., Zhang, Y. V., Montell, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Peripheral+coding+of+taste.">Peripheral coding of taste.</a> Neuron. 81 (5), 984-1000 (2014).</li><li>Rodrigues, V., Cheah, P. Y., Ray, K., Chia, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=malvolio,+the+Drosophila+homologue+of+mouse+NRAMP-1+(Bcg),+is+expressed+in+macrophages+and+in+the+nervous+system+and+is+required+for+normal+taste+behaviour.">malvolio, the Drosophila homologue of mouse NRAMP-1 (Bcg), is expressed in macrophages and in the nervous system and is required for normal taste behaviour.</a> EMBO J. 14 (13), 3007-3020 (1995).</li><li>Tanimura, T., Isono, K., Yamamoto, M. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Taste+sensitivity+to+trehalose+and+its+alteration+by+gene+dosage+in+Drosophila+melanogaster.">Taste sensitivity to trehalose and its alteration by gene dosage in Drosophila melanogaster.</a> Genetics. 119 (2), 399-406 (1988).</li><li>Weiss, L. A., Dahanukar, A., Kwon, J. Y., Banerjee, D., Carlson, J. 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+molecular+and+cellular+basis+of+bitter+taste+in+Drosophila.">The molecular and cellular basis of bitter taste in Drosophila.</a> Neuron. 69 (2), 258-272 (2011).</li><li>French, A. S., 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=Dual+mechanism+for+bitter+avoidance+in+Drosophila.">Dual mechanism for bitter avoidance in Drosophila.</a> J Neurosci. 35 (9), 3990-4004 (2015).</li><li>Deshpande, S. 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=Quantifying+Drosophila+food+intake:+comparative+analysis+of+current+methodology.">Quantifying Drosophila food intake: comparative analysis of current methodology.</a> Nat Methods. 11 (5), 535-540 (2014).</li></ol>

We have described a simple but effective protocol for determining taste preference in Drosophila. Versions of this assay are routinely used in experiments to determine the contributions of gustatory receptors (GRs) to perceiving the different qualities (bitter, sweet, sour, salty, and umami) of taste compounds. The Drosophila genome contains approximately 60 genes which encode 68 identified gustatory receptors by alternative splicing8,9. However, other proteins such as ionotropic glutamate re...

Animals use chemosensation to distinguish advantageous conditions apart from disadvantageous conditions. This perception can be critical for such things as determining the best food source, avoiding toxic substances or determining the best mating partner1. Chemosensation is often divided into two sensory components: olfactory senses and gustatory senses. A main distinguishing characteristic of these senses is that olfaction (smell) is used to sample the surrounding gaseous chemical environment while gustation (taste) requires physical contact with a nonvolatile substrate. Both sensory modalities stimulate neurological responses which are processed and decoded in the brain to produce the appropriate attractive or repulsive behavior2. These senses are therefore critical for animal survival.
The fruit fly Drosophila melanogaster is a model organism which continues to grow in popularity for use in understanding how insects perceive smell and taste. Fruit flies offer tremendous advantages over other model systems due to the wealth of genetic tools available for the dissection of molecular, cellular, and behavioral pathways. Work over the last 15 years has been particularly instrumental in characterizing the specific cellular identities, neuronal receptors, and signaling mechanisms involved in both smell and taste. Now, the power of Drosophila genetics is being used to further elucidate how these processes are coded at the single neuron and single circuit level3-6. Therefore, assays which provide easily scored readouts of alterations to sensory pathways are vital to the continuing advance of these fields.
While a great deal is known about how olfactory signals are coded and processed in the brain, much less is understood about similar mechanisms in the gustatory pathway. We describe here a protocol which can be used to ascertain taste preference in Drosophila. Drosophila, like mammals, generally prefer sweet tasting compounds as opposed to bitter tasting compounds. Any combination of these food sources can be utilized in this experimental design to determine how known genetic alterations affect taste choice. In addition, pharmacological intervention strategies can similarly be assessed for their effects on animals&#39; taste preference. The ease and flexibility of this assay makes it a useful paradigm for understanding the nature of gustatory perception in Drosophila.

<table border="0" cellpadding="0" cellspacing="0" width="1031">
	<tbody>
		<tr height="17">
			<td height="17" style="height:17px;width:543px;">Blue Food Coloring (Water, Propylene Glycol, FD&#38;C Blue 1 and Red 40, Propylparaben)</td>
			<td style="width:128px;">McCormick</td>
			<td style="width:111px;">N/A</td>
			<td style="width:251px;"></td>
		</tr>
		<tr height="17">
			<td height="17" style="height:17px;">Cryo/Freezer Boxes w/o Dividers</td>
			<td>Fisher</td>
			<td>03-395-455</td>
			<td></td>
		</tr>
		<tr height="17">
			<td height="17" style="height:17px;">Dumont #5 Forceps</td>
			<td>Fine Science Tools</td>
			<td>11251-20</td>
			<td></td>
		</tr>
		<tr height="17">
			<td height="17" style="height:17px;">Glacial Acetic Acid</td>
			<td>Fisher</td>
			<td>BP2401-500</td>
			<td></td>
		</tr>
		<tr height="17">
			<td height="17" style="height:17px;">Leica S6 E Stereozoom 0.63x-4.0x microscope</td>
			<td>W. Nuhsbaum, Inc.</td>
			<td>10446294</td>
			<td></td>
		</tr>
		<tr height="17">
			<td height="17" style="height:17px;">Petri Dish (100 x 15 mm)</td>
			<td>BD Falcon</td>
			<td>351029</td>
			<td>Reuseable if thoroughly washed and dried</td>
		</tr>
		<tr height="17">
			<td height="17" style="height:17px;">Quick-Snap Microtubes</td>
			<td>Alkali Scientific Inc.</td>
			<td>C3017</td>
			<td></td>
		</tr>
		<tr height="17">
			<td height="17" style="height:17px;">Red Food Coloring (Water, Propylene Glycol, FD&#38;C Reds 40 and 3, Propylparaben)</td>
			<td>McCormick</td>
			<td>N/A</td>
			<td></td>
		</tr>
		<tr height="17">
			<td height="17" style="height:17px;">Sucrose</td>
			<td>IBI Scientific</td>
			<td>IB37160</td>
			<td></td>
		</tr>
	</tbody>
</table>

taste preference assay for adult drosophila

Olfactory and gustatory perception of the environment is vital for animal survival. The most obvious application of these chemosenses is to be able to distinguish good food sources from potentially dangerous food sources. Gustation requires physical contact with a chemical compound which is able to signal through taste receptors that are expressed on the surface of neurons. In insects, these gustatory neurons can be located across the animal's body allowing taste to play an important role in many different behaviors. Insects typically prefer compounds containing sugars, while compounds that are considered bitter tasting are avoided. Given the basic biological importance of taste, there is intense interest in understanding the molecular mechanisms underlying this sensory modality. We describe an adult Drosophila taste assay which reflects the preference of the animals for a given tastant compound. This assay may be applied to animals of any genetic background to examine the taste preference for a desired soluble compound.

Some typical results from taste preference assays are shown below. In most experiments some variation in intensity of abdominal coloring will be seen (Figure 1). Any coloring in the abdomen whether intense or weak is considered a positive ingestion. It is therefore advisable for researchers to score animals while blind to the experimental condition so as to limit any potential biases.
It is also important to cho...

Watch this Scientific Journal Video about Taste Preference Assay for Adult Drosophila at JoVE.com

Taste Preference Assay for Adult Drosophila

Taste is an important sensory process which facilitates attraction to beneficial substances and avoidance of toxic substances. This protocol describes a simple ingestion assay for determining Drosophila gustatory preference for a given chemical compound.

Taste Preference Assay for Adult Drosophila

Olfactory and gustatory perception of the environment is vital for animal survival.  The most obvious application of these chemosenses is to be able to ...

The overall goal of this procedure is to determine the relative preference of adult Drosophila from one chemical tastant over another. This method can help answer key questions in the Drosophila taste field. Such as which genes are necessary for selecting between sweet compounds or potentially toxic, bitter compounds.The main advantage of this technique, is that it is straightforward and does not require any specialized instrumentation. Demonstrating the procedure will be Andrew Bantel, a technician from my laboratory. To begin the experiment, saturate a cotton ball with water at the bottom of a standard fly vial.Next, collect flies in sets of 100 animals on a CO2 pad and then add the flies to a prepared vial. Use a cotton ball to secure the vials closed. Then, place the vials on their side in an environmentally controlled incubator.Prepare the controlled tastant of one millimolar sucrose, by combining 10 microliters of 100 millimolar sucrose solution, 13 microliters of red food coloring, and 977 microliters of water. Next, prepare the experimental tastant of five millimolar sucrose. Then, create the assay chambers, by obtaining a 100 millimeter by 15 millimeter plastic petri dish, and placing three microliter drops of controlled tastant as close to the edge of the plate as possible at the 12 o'clock position.At the three o'clock position, place three 10 microliter drops of experimental tastant as close to the edge of the plate as possible. Place another three drops of the controlled tastant at the six o'clock position. Then, place another three drops of the experimental tastant at the nine o'clock position.Next, empty one vial of 100 starved flies onto a CO2 pad, just long enough to anaesthetize all animals. Brush the animals into the middle of a prepared assay chamber, and cover it with the dish lid. Place the assay chamber into an opaque cardboard box.Then, label the outside of the box with the condition and genotype being tested. Move the entire setup into an incubator. After two hours, place the assay chambers still contained within cardboard boxes, directly into a negative 20 degree Celsius freezer until they are ready for quantitation.Allow a single assay chamber to warm up to room temperature. Under a dissection microscope, use a brush to group the animals based on the color of their abdomen. Red, blue, or purple.Record the number of animals in each grouping. This graph shows the effects of varying concentrations of blue dye, while maintaining a constant concentration of red dye, revealing an optimum combination of 1.3%red, to 1.0%blue. Drosophila are naturally attracted to high sucrose concentrations, as seen by a preference index value near one, when given the choice between five millimolar sucrose and one millimolar sucrose.This preference was reversed with acid, which dropped the preference index to near zero. While performing this procedure, it's important to remember to test the food coloring additives, were there affects on the preference assay? The concentrations of each dye should have no impact on the performance index.

Research

JoVE Journal

Neuroscience

Methods to Assay Drosophila Behavior

Methods to Assay Drosophila Behavior

Drosophila melanogaster, the fruit fly, has been used to study molecular mechanisms of a wide range of human diseases such as cancer, cardiovascular ...

Drosophila Adult Olfactory Shock Learning

Drosophila Adult Olfactory Shock Learning

Drosophila have been used in classical conditioning experiments for over 40 years, thus greatly facilitating our understanding of memory, including the ...

Light Preference Assay to Study Innate and Circadian Regulated Photobehavior in Drosophila Larvae

Light Preference Assay to Study Innate and Circadian Regulated Photobehavior in Drosophila Larvae

Light acts as environmental signal to control animal behavior at various levels. The Drosophila larval nervous system is used as a unique model to answer ...

A Single-fly Assay for Foraging Behavior in Drosophila

A Single-fly Assay for Foraging Behavior in Drosophila

For many animals, hunger promotes changes in the olfactory system in a manner that facilitates the search for appropriate food sources. In this video ...

Membrane Potential Dye Imaging of Ventromedial Hypothalamus Neurons From Adult Mice to Study Glucose Sensing

Studies of neuronal activity are often performed using neurons from rodents less than 2 months of age due to the technical difficulties associated with ...

Electrophysiological Recording From Drosophila Labellar Taste Sensilla

Electrophysiological Recording From Drosophila Labellar Taste Sensilla

The peripheral taste response of insects can be powerfully investigated with electrophysiological techniques. The method described here allows the ...

Novel Assay for Cold Nociception in Drosophila Larvae

Novel Assay for Cold Nociception in Drosophila Larvae

How organisms sense and respond to noxious temperatures is still poorly understood. Further, the mechanisms underlying sensitization of the sensory ...

High-throughput Analysis of Locomotor Behavior in the Drosophila Island Assay

High-throughput Analysis of Locomotor Behavior in the Drosophila Island Assay

Advances in next-generation sequencing technologies contribute to the identification of (candidate) disease genes for movement disorders and other ...

Metabolic Analysis of Drosophila melanogaster Larval and Adult Brains

Metabolic Analysis of Drosophila melanogaster Larval and Adult Brains

This protocol describes a method for measuring the metabolism in Drosophila melanogaster larval and adult brains. Quantifying metabolism in whole organs ...

Preparing Adult Drosophila melanogaster for Whole Brain Imaging during Behavior and Stimuli Responses

Preparing Adult Drosophila melanogaster for Whole Brain Imaging during Behavior and Stimuli Responses

We present a method developed specifically to image the whole Drosophila brain during ongoing behavior such as walking. Head fixation and dissection are ...