Published: January 7th, 2013
Drosophila melanogaster is a powerful model organism for exploring the molecular basis of longevity regulation. This protocol will discuss the steps involved in generating a reproducible, population-based measurement of longevity as well as potential pitfalls and how to avoid them.
Aging is a phenomenon that results in steady physiological deterioration in nearly all organisms in which it has been examined, leading to reduced physical performance and increased risk of disease. Individual aging is manifest at the population level as an increase in age-dependent mortality, which is often measured in the laboratory by observing lifespan in large cohorts of age-matched individuals. Experiments that seek to quantify the extent to which genetic or environmental manipulations impact lifespan in simple model organisms have been remarkably successful for understanding the aspects of aging that are conserved across taxa and for inspiring new strategies for extending lifespan and preventing age-associated disease in mammals.
The vinegar fly, Drosophila melanogaster, is an attractive model organism for studying the mechanisms of aging due to its relatively short lifespan, convenient husbandry, and facile genetics. However, demographic measures of aging, including age-specific survival and mortality, are extraordinarily susceptible to even minor variations in experimental design and environment, and the maintenance of strict laboratory practices for the duration of aging experiments is required. These considerations, together with the need to practice careful control of genetic background, are essential for generating robust measurements. Indeed, there are many notable controversies surrounding inference from longevity experiments in yeast, worms, flies and mice that have been traced to environmental or genetic artifacts1-4. In this protocol, we describe a set of procedures that have been optimized over many years of measuring longevity in Drosophila using laboratory vials. We also describe the use of the dLife software, which was developed by our laboratory and is available for download (http://sitemaker.umich.edu/pletcherlab/software). dLife accelerates throughput and promotes good practices by incorporating optimal experimental design, simplifying fly handling and data collection, and standardizing data analysis. We will also discuss the many potential pitfalls in the design, collection, and interpretation of lifespan data, and we provide steps to avoid these dangers.
We recommend storing experimental foods, yeast paste, and grape agar plates that appear in the protocol at 4 °C and using them within 1-2 months as long as mold and dryness have not set in. Standard environmental conditions for both the larval and adult stage involve maintenance of flies in an incubator at 25 °C with a 12:12 hr light dark cycle and 60% relative humidity.
1. Preparation of Experimental Food
A simplified scheme of the protocol is presented in Figure 1, where key steps are outlined. The synchronization part of the protocol can be used for various assays that require age-matched adult flies.
Typical survivorship curves of wild-type flies are shown in Figure 2a, using the dLife experiment management software (Figure 2b,c). Adult males usually live shorter, with both populations achieving a mean and median longevity of >50 days on .......
The protocol presented here describes a method for producing reproducible measurements of adult longevity in Drosophila that is adaptable for assessment of genetic, pharmacological, and environmental interventions. Crucial aspects of the protocol include carefully controlling the larval development environment, minimizing adult stress, and minimizing bias across experimental groups and controls. We also present the use of the dLife lifespan experiment management software. By simply attaching a bar code or RFID t.......
This work was supported by funding from the Ellison Medical Foundation (SDP, http://www.ellisonfoundation.org/index.jsp), NIH K01AG031917 (NJL, http://www.nih.gov/), NIH 5T32GM007315-35 (JR) and NIH R01AG030593 (SDP). This work utilized the resources of the Drosophila Aging Core (DAC) of the Nathan Shock Center of Excellence in the Biology of Aging funded by the National Institute of Aging P30-AG-013283 (http://www.nih.gov/). The authors would like to thank the Pletcher Laboratory for helpfu....
|Name of the reagent
|Active Dry Yeast
|Grape Agar Powder Premix
|Large Embryo Collection Cages
|Large Replacement End Caps
|6 oz Square Bottom Bottles, polypropylene
|Flugs Closures for Stock Bottles
|Drosophila Vials, Wide, Polystrene
|Flugs Closures for Wide Vials
|Wide Orifice Aardvark Pipet Tips, 200 ul
|Flystuff Flypad, Standard Size
|BD Falcon 15 ml Conical Centrifuge Tubes
|Fisherbrand Petri Dishes with Clear Lids, Raised Ridge; 100 O.D. x 15 mm H;
|Kimax* Colorware Flasks 1,000 ml yellow
|PBS pH 7.4 10x
|Fly Food Preservative
|Propionic Acid, 99%
|Fly Food Preservative
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