Measuring Crop Motility and Food Passaging in Drosophila

Summary

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

Abstract

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.

Introduction

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 wi....

Protocol

1. Maintaining and preparing experimental flies

1. Maintain flies in vials containing 10 mL of freshly made food (1% agar, 2.4% brewer’s yeast, 3% sucrose, 5% cornmeal) in an incubator at 25 °C with 60% humidity. Set the light cycle of the incubator to 12-h light:12-h dark.
2. To ensure that a large number of the desired genotype flies ecloses simultaneously, culture young flies (1−3 days old) in standard food with dry yeast on the surface for 3 days. Transfer the adults to a new food via.......

Discussion

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 ingestion^10,11. The method of feces number counting can be used to estimate the amou.......

Materials

Name	Company	Catalog Number	Comments
96-well plate	Thermo fisher	269620
Brillant Blue FCF	Solarbio	E8500	also called FD&C Blue No. 1
Centrifuge	Thermo fisher	Heraeus Pico 17
Spectrophotometer	Spectra Max	cMax plus
Tweezers	Dumont	11252-30