This work was supported by National Natural Science Foundation of China (No. 31872287), Natural Science Foundation of Jiangsu Province (NO. BK20181456) and Six talent peaks project in Jiangsu Province (No. SWYY-146).

1. Maintaining and preparing experimental flies
<ol>
	<li>Maintain flies in vials containing 10 mL of freshly made food (1% agar, 2.4% brewer&#8217;s yeast, 3% sucrose, 5% cornmeal) in an incubator at 25 &#176;C with 60% humidity. Set the light cycle of the incubator to 12-h light:12-h dark.</li>
	<li>To ensure that a large number of the desired genotype flies ecloses simultaneously, culture young flies (1&#8722;3 days old) in standard food with dry yeast on the surface for 3 days. Transfer the adults to a new food via...

<ol>
	<li>Kusano, M., 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=Gastrointestinal+motility+and+functional+gastrointestinal+diseases.">Gastrointestinal motility and functional gastrointestinal diseases.</a> Current Pharmaceutical Design. 20 (16), 2775-2782 (2014).</li><li>Reiter, L. T., Potocki, L., Chien, S., Gribskov, M., Bier, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+systematic+analysis+of+human+disease-associated+gene+sequences+in+Drosophila+melanogaster.">A systematic analysis of human disease-associated gene sequences in Drosophila melanogaster.</a> Genome Research. 11 (6), 1114-1125 (2001).</li><li>Apidianakis, Y., Rahme, L. 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A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Quiescent+gastric+stem+cells+maintain+the+adult+Drosophila+stomach.">Quiescent gastric stem cells maintain the adult Drosophila stomach.</a> Proceedings of the National Academy of Sciences of the United States of America. 108 (43), 17696-17701 (2011).</li><li>Ren, J., 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=Beadex+affects+gastric+emptying+in+Drosophila.">Beadex affects gastric emptying in Drosophila.</a> Cell Research. 24 (5), 636-639 (2014).</li><li>Xi, J., 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+TORC1+inhibitor+Nprl2+protects+age-related+digestive+function+in+Drosophila.">The TORC1 inhibitor Nprl2 protects age-related digestive function in Drosophila.</a> Aging. 11 (21), 9811-9828 (2019).</li><li>Wei, Y., Reveal, B., Cai, W., Lilly, M. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+GATOR1+Complex+Regulates+Metabolic+Homeostasis+and+the+Response+to+Nutrient+Stress+in+Drosophila+melanogaster.">The GATOR1 Complex Regulates Metabolic Homeostasis and the Response to Nutrient Stress in Drosophila melanogaster.</a> G3. 6 (12), 3859-3867 (2016).</li><li>Ja, W. 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=Prandiology+of+Drosophila+and+the+CAFE+assay.">Prandiology of Drosophila and the CAFE assay.</a> Proceedings of the National Academy of Sciences of the United States of America. 104 (20), 8253-8256 (2007).</li><li>Diegelmann, 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=The+CApillary+FEeder+Assay+Measures+Food+Intake+in+Drosophila+melanogaster.">The CApillary FEeder Assay Measures Food Intake in Drosophila melanogaster.</a> Journal of Visualized Experiments. (121), e55024 (2017).</li><li>Edgecomb, R. S., Harth, C. E., Schneiderman, A. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Regulation+of+feeding+behavior+in+adult+Drosophila+melanogaster+varies+with+feeding+regime+and+nutritional+state.">Regulation of feeding behavior in adult Drosophila melanogaster varies with feeding regime and nutritional state.</a> Journal of Experimental Biology. 197, 215-235 (1994).</li><li>Peller, C. R., Bacon, E. M., Bucheger, J. A., Blumenthal, E. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Defective+gut+function+in+drop-dead+mutant+Drosophila.">Defective gut function in drop-dead mutant Drosophila.</a> Journal of Insect Physiology. 55 (9), 834-839 (2009).</li><li>Chtarbanova, 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=Drosophila+C+virus+systemic+infection+leads+to+intestinal+obstruction.">Drosophila C virus systemic infection leads to intestinal obstruction.</a> Journal of Virology. 88 (24), 14057-14069 (2014).</li><li>Solari, P., 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=Opposite+effects+of+5-HT/AKH+and+octopamine+on+the+crop+contractions+in+adult+Drosophila+melanogaster:+Evidence+of+a+double+brain-gut+serotonergic+circuitry.">Opposite effects of 5-HT/AKH and octopamine on the crop contractions in adult Drosophila melanogaster: Evidence of a double brain-gut serotonergic circuitry.</a> PLoS One. 12 (3), 0174172 (2017).</li></ol>

The authors have nothing to disclose.

In Drosophila ingested food moves from the crop to the gut for digestion. During this process, the nutrients are absorbed, and the waste is expelled out of the body as feces. Thus, comparing food ingestion together with feces ejection can be used to roughly assess the speed of food movement in the body. The method of capillary feeder (CAFE) is widely used to measure food ingestion10,11. The method of feces number counting can be used to estimate the amou...

Most animals have a digestive tube called the gastrointestinal (GI) tract to absorb energy and nutrients from the environment. The human GI tract is composed of four parts: the esophagus, stomach, small intestine, and large intestine (colon). Food passage from the stomach to the intestine is essential for nutrient absorption. Some effectors, such as aging, toxic drugs, and infection, cause disordered GI tract motility and gastric emptying, which is related to some diseases and their symptoms such as dyspepsia, gastroesophageal reflux disease, and constipation1.
The fruit fly (Drosophila melanogaster) is a widely used model animal in biomedical research due to its easy genetic manipulation. Importantly, about 77% of genes associated with human disease have a homolog in Drosophila2. Research using Drosophila has made enormous advances in our understanding of many disease mechanisms. As a powerful genetic model organism, Drosophila is widely used in GI tract research3. Drosophila has a simpler digestive tract, which is divided into three discrete domains: foregut, midgut, and hindgut4. The crop, a part of the foregut, is a bag-like structure that serves as a site for ingested food storage. The midgut is a long tube and functions as the site for food digestion and nutrient absorption through the epithelial layer, which consists of absorptive enterocytes (ECs) and secretory enteroendocrine (EE) cells5. Interestingly, the stomach function in Drosophila is divided into two parts: the crop functions as food storage and the copper cell region (CCR) is a highly acidic region with a pH &#60; 36. In Drosophila, the ingested food is initially moved to the crop and subsequently pumped into the midgut7. Thus, the crop plays a critical role in food passaging. Enveloped by visceral muscles and consisting of a complex array of valves and sphincters, the crop keeps contracting and moving food into the midgut for further digestion.
This protocol allows for the detection of food movement from the crop to the midgut in Drosophila. Crop contraction is evaluated by counting crop contraction frequency. In addition, the effect of the crop on food passaging is investigated by detecting the food distribution between crop and gut. Furthermore, the food distribution can be used to reflect immediate food movement or basic food status using different feeding periods. Taken together, this protocol provides methods to rapidly evaluate crop motility and food passaging in Drosophila.

<table>
	<tbody>
		<tr>
			<td>96-well plate</td>
			<td>Thermo fisher</td>
			<td>269620</td>
			<td></td>
		</tr>
		<tr>
			<td>Brillant Blue FCF</td>
			<td>Solarbio</td>
			<td>E8500</td>
			<td>also called FD&#38;C Blue No. 1</td>
		</tr>
		<tr>
			<td>Centrifuge</td>
			<td>Thermo fisher</td>
			<td>Heraeus Pico 17</td>
			<td></td>
		</tr>
		<tr>
			<td>Spectrophotometer</td>
			<td>Spectra Max</td>
			<td>cMax plus</td>
			<td></td>
		</tr>
		<tr>
			<td>Tweezers</td>
			<td>Dumont</td>
			<td>11252-30</td>
			<td></td>
		</tr>
	</tbody>
</table>

measuring crop motility and food passaging in drosophila

Most animals use the gastrointestinal (GI) tract to digest food. The movement of the ingested food in the GI tract is essential for nutrient absorption. Disordered GI motility and gastric emptying cause multiple diseases and symptoms. As a powerful genetic model organism, Drosophila can be used in GI motility research. The Drosophila crop is an organ that contracts and moves food into the midgut for further digestion, functionally similar to a mammalian stomach. Presented is a protocol to study Drosophila crop motility using simple measurement tools. A method for counting crop contractions to evaluate crop motility and a method for detecting the distribution of food dyed blue between the crop and gut using a spectrophotometer to investigate the effect of the crop on food passaging is described. The method was used to detect the difference in crop motility between control and nprl2 mutant flies. This protocol is both cost-efficient and highly sensitive to crop motility.

These methods to count crop contraction rate and detect dyed food distribution can be used to evaluate crop function on food motility. The crop contraction reflects the frequency of pushing food into the gut. The distribution of dye in the fly after a short feeding period indicates immediate food passaging from crop to midgut.
Target of rapamycin complex 1 (TORC1) is a master regulator that mediates nutrient and cell metabolism. TORC1 inhibition extends lifespan in many organisms, including <e...

Watch this Scientific Journal Video about Measuring Crop Motility and Food Passaging in Drosophila at JoVE.com

Measuring Crop Motility and Food Passaging in Drosophila

The goal of this protocol is to measure crop contraction and quantify food distribution in the Drosophila gut.

Measuring Crop Motility and Food Passaging in Drosophila

Most animals use the gastrointestinal (GI) tract to digest food. The movement of the ingested food in the GI tract is essential for nutrient absorption. ...

This method is used to evaluate the crop motility through counting crop contraction and detecting the food distribution in just the digestive. The advantage of this technique is that it's continually evaluates crop motility. It's low cost and easy to perform.This method makes it possible to use just filler as a model to study digestive function on the food passages in the gastrointestinal tract. Helping to demonstrate the process will be Junmeng Xi, a graduate student from my laboratory. Maintain flies in vials containing 10 milliliters of freshly made food in a 25 degree celsius incubator with 60%humidity and a 12 hour light, 12 hour dark cycle.Ensure that a large number of the desire phenotype flies eclose simultaneously by culturing young flies with standard food with dry yeast then transfer the adult flies to a vial with wet yeast and allow two days for egg laying. Leave the eggs in the incubator to develop and transfer adult flies to a new vial to collect more eggs. Collect the eclosed male or female flies each day and culture them in new vials with standard food to the desired age.Anesthetize the flies with carbon dioxide and transfer one fly into a dissecting plate well with 200 microliters of PBS. Grasp the fly at its thorax with a pair of tweezers and open the thorax with another pair of tweezers then pull the ends in opposite directions to open the abdomen. Carefully take the crop and gut out of the body and wait for the fly to wake up.When the fly is awake, count the number of times the crop contracts in one minute. Repeat the contraction counting five times, waiting 30 seconds between each count. Weigh the blue dye and dissolve it in PBS at a 20%concentration.Then stir it into the boiled liquid maintenance food to a final concentration of 5%during the food cooling process. After keeping flies in vials with starvation food for four hours, transfer them into new vials with the dyed food and culture them for the desired time, keeping in mind that at maintenance conditions the food passes through the fly in about two hours. Transfer an anesthetized fly into a dissecting plate well containing 200 microliters of PBS.Use tweezers to grasp the fly at the thorax and remove the head with another pair of tweezers, then transfer the body to a new well with PBS and wash it with gentle shaking to remove the dye attached to the body. Open the abdomen with two pair of tweezers and carefully separate the whole gut from the body. Take the crop off of the whole gut and put it in a tube with 100 microliters of PBS.Put the rest of the gut in another tube with 100 microliters of PBS then use pipette tips to grind the crop and gut and dissolve the dye in PBS. Repeat the dissection until enough crops and guts are collected. After collecting the samples, centrifuge the tubes at the highest speed for one minute and transfer 90 microliters of supernatant to well of a 96 well plate.Make a series of standard blue dye dilutions at concentrations from one times 10 to the 7 to 10 to the 4th grams per milliliter and add them to the wells. Measure the absorbance at 630 nanometers of the wells and use the standard measurements to plot a line graph of absorbance vs dye concentration. Then use the curve to calculate the dye concentration of the samples.The crop motility assay was used to count crop contractions on three day old NPRL mutant flies and genetic background controls. The mutation was found to significantly decrease the rate of crop contraction. To further confirm the function of NPRL2 on the crop, food movement was detected by feeding dyed food to the flies.All flies had similar amounts of dye in the crop but the NPRL2 flies had less dye in the gut which may be associated with the decreased crop contraction rate. When typing this protocol, make sure that the crop remains contact to the body and the fly is alive and awake. Otherwise, the crop will lose the ability to contract.During the dissection process, the crop and the gut should be in contact. If dye leaks into the dissection medium, the sample cannot be used anymore. Let's just fill our appetite and the food ejection within a short time can also be evaluated by detecting the dye amount in the whole gut.

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JoVE Journal

Biology

5.3K ビュー.  Yangzhou University. この方法は、作物の収縮を数え、消化器だけで食物分布を検出することによって作物運動性を評価するために使用されます。この技術の利点は、作物の運動性を継続的に評価していることです。低コストで、簡単に実行できます。この方法は、消化管内の食物通路の消化機能を研究するモデルとしてフィラーのみを使用することを可能にする。このプロセスのデモ?...