The authors acknowledge that support for work in the author&#39;s laboratory is provided by an HHMI Faculty Scholar Award and startup funds from the Children&#39;s Research Institute at UT Southwestern Medical Center.

NOTE: The standard laboratory line Oregon R was used as a WT control. All flies were reared on standard cornmeal-molasses medium (containing molasses, agar, yeast, cornmeal, tegosept, propionic acid, and water) at room temperature with 12/12 h light/dark circadian rhythm.
1. Preparing for the assay
<ol>
	<li>Collect female flies (0-2 days old, non-virgin) under CO2 anesthesia and allow them to recover on standard cornmeal food for at least 3 days before experiment...

<ol>
	<li>Hollander, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+composition+and+mechanism+of+formation+of+gastric+acid+secretion.">The composition and mechanism of formation of gastric acid secretion.</a> Science. 110 (2846), 57-63 (1949).</li><li>Forte, J. G., Zhu, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Apical+recycling+of+the+gastric+parietal+cell+H,+K-ATPase.">Apical recycling of the gastric parietal cell H, K-ATPase.</a> Annual Review of Physiology. 72, 273-296 (2010).</li><li>Samuelson, L. C., Hinkle, K. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Insights+into+the+regulation+of+gastric+acid+secretion+through+analysis+of+genetically+engineered+mice.">Insights into the regulation of gastric acid secretion through analysis of genetically engineered mice.</a> Annual Review of Physiology. 65, 383-400 (2003).</li><li>Yao, X., Forte, J. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cell+biology+of+acid+secretion+by+the+parietal+cell.">Cell biology of acid secretion by the parietal cell.</a> Annual Review of Physiology. 65, 103-131 (2003).</li><li>Driver, I., Ohlstein, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Specification+of+regional+intestinal+stem+cell+identity+during+Drosophila+metamorphosis.">Specification of regional intestinal stem cell identity during Drosophila metamorphosis.</a> Development. 141 (9), 1848-1856 (2014).</li><li>Overend, , 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=Molecular+mechanism+and+functional+significance+of+acid+generation+in+the+Drosophila+midgut.">Molecular mechanism and functional significance of acid generation in the Drosophila midgut.</a> Scientific Reports. 6, 27242 (2016).</li><li>Shanbhag, S., Tripathi, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Epithelial+ultrastructure+and+cellular+mechanisms+of+acid+and+base+transport+in+the+Drosophila+midgut.">Epithelial ultrastructure and cellular mechanisms of acid and base transport in the Drosophila midgut.</a> Journal of Experimental Biology. 212, 1731-1744 (2009).</li><li>Dubreuil, R. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Copper+cells+and+stomach+acid+secretion+in+the+Drosophila+midgut.">Copper cells and stomach acid secretion in the Drosophila midgut.</a> International Journal of Biochemistry and Cell Biology. 36 (5), 745-752 (2004).</li><li>Martorell, , 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=Conserved+mechanisms+of+tumorigenesis+in+the+Drosophila+adult+midgut.">Conserved mechanisms of tumorigenesis in the Drosophila adult midgut.</a> PLoS ONE. 9 (2), 88413 (2014).</li><li>Strand, M., Micchelli, C. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Regional+control+of+Drosophila+gut+stem+cell+proliferation:+EGF+establishes+GSSC+proliferative+set+point+&amp;+controls+emergence+from+quiescence.">Regional control of Drosophila gut stem cell proliferation: EGF establishes GSSC proliferative set point &amp; controls emergence from quiescence.</a> PLoS One. 8 (11), 80608 (2013).</li><li>Storelli, G., 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+perpetuates+nutritional+mutualism+by+promoting+the+fitness+of+its+intestinal+symbiont+Lactobacillus+plantarum.">Drosophila perpetuates nutritional mutualism by promoting the fitness of its intestinal symbiont Lactobacillus plantarum.</a> Cell Metabolism. 27 (2), 362-377 (2018).</li><li>Abu, F., 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=Communicating+the+nutritional+value+of+sugar+in+Drosophila.">Communicating the nutritional value of sugar in Drosophila.</a> Proceedings of the National Academy of Sciences of the United States of America. 115 (12), 2829-2838 (2018).</li><li>Blecker, U., Gold, B. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Gastritis+and+ulcer+disease+in+childhood.">Gastritis and ulcer disease in childhood.</a> European Journal of Pediatrics. 158 (7), 541-546 (1999).</li></ol>

The authors have no conflicts of interest to disclose.

A critical step in this protocol is the proper dissection of the gut to visualize the CCR for the acidification phenotype. The acid released from the copper cells is confined to the CCR when the gut is intact. However, during dissection, leakage caused by rupture of the intestine can lead to diffusion of acid from the CCR and result in a gut mistakenly scored as a negative for acidification. In addition, the yellow color indicative of acidification fades within 5-10 min after dissection, underscoring the importance of sc...

In the insect gut, copper cells share cellular and functional similarities with the acid-producing gastric parietal cells (also known as oxyntic) of the mammalian stomach. This group of cells releases acid into the intestinal lumen. The function of acid secretion and anatomy is evolutionarily conserved. The major components of the discharged acid are hydrochloric acid and potassium chloride. The chemical mechanism of acid formation in the cells depends on carbonic anhydrase. This enzyme generates a bicarbonate ion from CO2 and water, which liberates a hydroxyl ion that is then discharged into the lumen through a proton pump in exchange for potassium. Chloride and potassium ions are transported into the lumen by conductance channels resulting in the formation of hydrochloric acid and potassium chloride, the main component of gastric juice1,2,3,4.
Although the mechanisms of acid formation are well understood, much less is known about the physiological mechanisms that regulate acid secretion. The goal of developing this method is to help better delineate the cellular pathways that coordinate acid formation and secretion and determine the role of acid in mediating intestinal physiology and homeostasis. The rationale behind the development and use of this technique is to provide a consistent and reliable method to study the process of gut acidification in Drosophila and non-model organisms. Although a standard protocol for determining Drosophila midgut acidification currently exists2,5,6, significant variability was observed in the extent of acidification in wild-type (WT) flies while using this protocol for studying copper cell function. To understand the basis for this observed variability and obtain consistent results, several aspects of the standard protocol were optimized as described below.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Bromophenol blue</td>
			<td>Sigma-Aldrich</td>
			<td></td>
			<td>B0126</td>
		</tr>
		<tr>
			<td>cellSens software</td>
			<td>Olympus</td>
			<td></td>
			<td>Image aqusition (https://www.olympus-lifescience.com/en/software/cellsens)</td>
		</tr>
		<tr>
			<td>D. simulans</td>
			<td>Drosophila Species Stock Center at the University of California</td>
			<td></td>
			<td>Riverside California1 (https://www.drosophilaspecies.com/)</td>
		</tr>
		<tr>
			<td>D. erecta</td>
			<td>Drosophila Species Stock Center at the University of California</td>
			<td></td>
			<td>Dere cy1(https://www.drosophilaspecies.com/)</td>
		</tr>
		<tr>
			<td>D. pseudoobscura</td>
			<td>Drosophila Species Stock Center at the University of California</td>
			<td></td>
			<td>Eugene, Oregon(https://www.drosophilaspecies.com/)</td>
		</tr>
		<tr>
			<td>D. mojavensis</td>
			<td>Drosophila Species Stock Center at the University of California</td>
			<td></td>
			<td>Chocolate Mountains, California (https://www.drosophilaspecies.com/)</td>
		</tr>
		<tr>
			<td>Forceps</td>
			<td>Inox Biology</td>
			<td></td>
			<td>Catalog# 11252-20</td>
		</tr>
		<tr>
			<td>Fuji</td>
			<td>Fuji</td>
			<td></td>
			<td>Image processing (https://hpc.nih.gov/apps/Fiji.html)</td>
		</tr>
		<tr>
			<td>Glass slide</td>
			<td>VWR</td>
			<td></td>
			<td>Catalog#16005-108</td>
		</tr>
		<tr>
			<td>Kim wipes Tissue</td>
			<td>Kimtech</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Microscope and camera</td>
			<td>Olympus SZ61 microscope equipped with an Olympus D-27 digital camera</td>
			<td></td>
			<td>Imaging</td>
		</tr>
		<tr>
			<td>Oregon R</td>
			<td>Bloomington Drosophila Stock</td>
			<td></td>
			<td>(https://bdsc.indiana.edu/ # 2376)</td>
		</tr>
		<tr>
			<td>Petri dishes</td>
			<td>Fisher Scientific</td>
			<td></td>
			<td>Catalog #FB0875713A</td>
		</tr>
		<tr>
			<td>Phosphate-buffered Saline (PBS)</td>
			<td>HyClone</td>
			<td></td>
			<td>Catalog # SH30258.01</td>
		</tr>
		<tr>
			<td>Stereomicroscope</td>
			<td>Olympus SZ51</td>
			<td></td>
			<td>Visual magnification</td>
		</tr>
	</tbody>
</table>

monitoring gut acidification in the adult drosophila intestine

The fruit fly midgut consists of multiple regions, each of which is composed of cells that carry out unique physiological functions required for the proper functioning of the gut. One such region, the copper cell region (CCR), is localized to the middle midgut and consists, in part, of a group of cells known as copper cells. Copper cells are involved in gastric acid secretion, an evolutionarily conserved process whose precise role is poorly understood. This paper describes improvements in the current protocol used to assay for acidification of the adult Drosophila melanogaster gut and demonstrates that it can be used on other species of flies. In particular, this paper demonstrates that gut acidification is dependent on the fly's nutritional status and presents a protocol based on this new finding. Overall, this protocol demonstrates the potential usefulness of studying Drosophila copper cells to uncover general principles underlying the mechanisms of gut acidification.

We starved Oregon R female flies for more than 20 h and then fed them food supplemented with BPB (2%) for ~12 h, as described previously7,8,9,10,11. Bromophenol blue (BPB) is a pH-sensing dye. It changes from yellow at pH 3.0 to blue at pH 4.6 and above. Following gut dissection, as previously reported, some flies were found to produce acid as indicated by yel...

Watch this Scientific Journal Video about Monitoring Gut Acidification in the Adult Drosophila Intestine at JoVE.com

Monitoring Gut Acidification in the Adult Drosophila Intestine

Here, we present a standardized protocol for monitoring gut acidification in Drosophila melanogaster with optimal output. We first use this protocol for gut acidification monitoring in Drosophila melanogaster and then demonstrate its use in non-model Drosophila species.

Monitoring Gut Acidification in the Adult Drosophila Intestine

The fruit fly midgut consists of multiple regions, each of which is composed of cells that carry out unique physiological functions required for the ...

This is the fastest and right protocol to monitor the Drosophila gut acidification with robust and authentic results. This method will help to determine the role of gut acidification in multiple organisms. And this phenomenon is The simplicity of this technique is the main advantage.As such, it can be utilized for the non-model organisms. This method can monitor the acid release for many systems including the cell lines and 3D on live cultures. This technique is simple with minimal effort.Food containing Bromophenol blue should be prepared fresh. In addition, while dissection gut should not be stretched. Start arranging for the gut acidification monitoring assay with the preparation of the fly food with pH sensing Bromophenol blue or BPB dye.To do so, melt the fly food in a microwave and let it cool until lukewarm. Add one milliliter of 4%BPB to one milliliter of the lukewarm food with a mixing well. Using a pipette, add the fly food containing BPB into a single dot of approximately 200 microliters in the center of a petri dish.Next, collect zero to two-days-old non-virgin female Drosophila melanogaster flies, and allow the flies to recover on standard corn meal food. Before the experiment, starve the flies for 24 hours at room temperature in a vial containing a laboratory wipe tissue soaked with approximately two milliliters of deionized water. Transfer starved flies into a petri dish containing single dots of the freshly prepared fly food, supplemented with 2%BPB, to allow the flies to forage for four hours at room temperature while exposed to light.After four hours collect the flies, then proceed to surgically isolate the guts of the anesthetized flies in 1X PBS with forceps under a stereo microscope. Count the number of the flies that show robust BPB standing in the guts, and calculate the percentage using the equation. Following dissection, mount the samples in PBS onto a glass slide and place the prepared slide under the microscope.Then adjust the focus using the IPS. Once done, shut off the IPS to open the shutter for the camera. Following gut dissection, some Drosophila melanogaster female flies were found to produce acid as indicated by the yellow color in the CCR of the gut.Whereas the intestines of some flies were blue suggesting a failure of the flies to acidify their guts. Within 30 minutes, approximately 20%of flies had acidified the gut. After an hour, 40%of the gut guts showed acidification, while after two to three hours of feeding, the percentage of acidified guts increased to 60 to 70%Almost 90 to 95%of the guts were acidified when flies were fed for four hours.No difference in gut acidification was observed for two different temperature conditions. The efficiency of the gut acidification protocol was assessed in various Drosophila species. All the tested species showed robust gut acidification, suggesting the protocol can be applied to other organisms.The most important thing to remember, is to place the star flies into the petri plate with yeast and Bromophenol blue for four hours. This technique will help to understand the basic biology and cellular pathway involved in the gut acidification. It should also help to identify the drug target to create the diseases related to the gut acidification.

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3.0K vistas.  University of Texas Southwestern Medical Center. Este es el protocolo más rápido y correcto para monitorear la acidificación intestinal de Drosophila con resultados robustos y auténticos. Este método ayudará a determinar el papel de la acidificación intestinal en múltiples organismos. Y este fenómeno es La simplicidad de esta técnica es la principal ventaja.Como tal, se puede utilizar para los organismos no modelo. Este método puede monitorear la liberación de ácido para muchos sistemas, incluidas las líneas celulares y...