Endurance Training Protocol and Longitudinal Performance Assays for <em>Drosophila melanogaster</em>

Abstract

One of the most pressing problems facing modern medical researchers is the surging levels of obesity, with the consequent increase in associated disorders such as diabetes and cardiovascular disease [1][2][3] . An important topic of research into these associated health problems involves the role of endurance exercise as a beneficial intervention.Exercise training is an inexpensive, non-invasive intervention with several beneficial results, including reduction in excess body fat .Despite the importance of exercise as a tool for combating several important age-related diseases, extensive longitudinal genetic studies have been impeded by the lack of an endurance training protocol for a short-lived genetic model species. The variety of genetic tools available for use with Drosophila, together with its short lifespan and inexpensive maintenance, make it an appealing model for further study of these genetic mechanisms. With this in mind we have developed a novel apparatus, known as the Power Tower, for large scale exercise-training in Drosophila melanogaster 11. The Power Tower utilizes the flies' instinctive negative geotaxis behavior to repetitively induce rapid climbing. Each time the machine lifts, then drops, the platform of flies, the flies are induced to climb. Flies continue to respond as long as the machine is in operation or until they become too fatigued to respond. Thus, the researcher can use this machine to provide simultaneous training to large numbers of age-matched and genetically identical flies. Additionally, we describe associated assays useful to track longitudinal progress of fly cohorts during training. Video LinkThe video component of this article can be found at https://www.jove.com/video/3786/ Protocol 1. Power Tower Setup and Operation 1. The Power Tower is placed on a rectangular piece of plywood that is clamped to a table. A 4.5 rpm gear motor from Grainger rests on top of four 2"x6" boards and one ¾ inch plywood board. The motor, an AC/DC speed control, a fuse, and an on/off switch are wired together into a juncture box. 2. To cool the motor, a hole 3 inches in diameter is cut into a vertical ½ inch piece of plywood. On one side, a 3-inch fan is attached to the plywood, and on the other, a 3-inch diameter metal cylinder is attached. 3. A custom-made rotating arm with a roller mounted on the end is connected to the motor. The motor and attached arm rotate in a clockwise direction, pushing down one side of a bent ¾ inch square tube stock that is attached to the plywood with a door hinge. A wheel is attached to the top side of the tube stock below the platform to allow it to roll against the platform that is directly above it. 4. The arm pushes down on one end of the tube stock and lifts the opposite end, raising a two-level platform (Figure 1D). When the roller on the arm clears the tube stock it allows the arm to return to the starting position, dropping the platform back down (Figure 1F). 5. The platforms consist of racks that are placed on top of plywood and secured by bungee co...

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“…Flies were tested 5 times per week for 5 weeks to assess the decline in negative geotaxis speed with age. Climbing endurance was measured using the fatigue assay as previously described (28).…”

Dietary composition regulatesDrosophilamobility and cardiac physiology

“…Negative geotaxis speed is known to decline with age (Gargano et al, 2005) and increase with exercise training Tinkerhess et al, 2012a). Here, we performed longitudinal measurements five times per week to track the changing negative geotaxis performance of aging flies on various diets.…”

“…Genotype comparisons were also performed using standard least-squares regression. Climbing endurance was measured using the fatigue assay described previously (Tinkerhess et al, 2012a). Eight vials of flies from each diet treatment were subjected to the fatigue assay at two time points: once in the first week of life (day3), and once in the fourth week of life (day26).…”

“…Flies were divided into groups of 20, then placed on an automated negative geotaxis-inducing machine, known as the Power Tower Tinkerhess et al, 2012a) until such time as fewer than five flies per vial were able to climb above a 2in (50.8mm) mark on the machine. At this time, the vial was considered fatigued, and removed from the machine.…”

“…These effects include post-training improvements to fatigue tolerance (Matoba and Gollnick, 1984;Booth and Thomason, 1991;Tinkerhess et al, 2012a), speed (Chandler and Hadley, 1996;Fitts and Widrick, 1996;Piazza et al, 2009) and cardiac performance Kemi and Wisloff, 2010;El-Haddad et al, 2011). In mice and humans, endurance exercise is known to improve glucose sensitivity (Henriksson, 1995;Hayashi et al, 1997), while in mice and flies, endurance exercise is known to increase autophagy (He et al, 2012;Sujkowski et al, 2012).…”