The authors wish to acknowledge Akira Chiba for intellectual support, material support, and stocks. Thanks to Julia Dallman for comments.

1. Fly Work
<ol>
	<li>Maintain flies on standard cornmeal-agar-molasses-yeast medium at room temperature10.</li>
	<li>For crosses, isolate virgins within 6 hr of eclosion. After crossing to males of the desired genotype, change flies to new vials every 3-4 days.</li>
</ol>
Note: For these experiments, Gal4 line A9 was used to drive expression of transgenes in the wing. Fly stocks can be obtained from the stock center in Bloomington. Stocks used in these experiments include A9-Gal4 (Bl#8761), His2Av-GFP (Bl#5941), Sco/CyO HsCre (Bl#1092), UAS-ChRFP-Tub (Bl#25773), lollibow11.
2. Selection and Mounting of Pupae
<ol>
	<li>Stage pupae either by collecting them as white prepupae (WPP) and keeping them at 25 &#176;C until they reach the appropriate age or by using morphological criteria12.</li>
	<li>To observe cell divisions, select pupa that have recently undergone head eversion. From this time until just before eclosion (at &#62;96 hr), pupae are immobile allowing extended time-lapse observation.</li>
	<li>Remove pupae from the vials by first touching them with a paintbrush moistened with water, waiting for a minute to allow the water to loosen the adhesive&#160;and then gently prodding them onto the paintbrush.</li>
	<li>Gently wash selected pupae by prodding them with a paintbrush in water to remove the salivary gland adhesive and food particles.</li>
	<li>Transfer clean pupae to a 25 mm Petri dish with a coverslip bottom (number 1 &#189; coverslips).</li>
	<li>Using thin strips of either modeling clay or dental wax as a support, mount pupae so that the tissue of interest is closest to the coverslip. 
	Note: In the studies described here, pupal wings, legs, abdominal histoblasts or dorsal notum have been observed. In practice, any tissue within 20 &#181;m of the surface of the pupal case is observable.</li>
	<li>Orient pupae carefully so that the tissue of interest is parallel to the glass coverslip surface.</li>
	<li>Once pupae are mounted, use a paintbrush to transfer a thin layer of thiodiethylene glycol (TDG) to the space between the pupa and the coverslip.</li>
</ol>
Note: TDG reduces surface scattering, matches the refractive index of oil, and allows oxygen to permeate the tissue13. Use of oils is not recommended, as they tend to deprive the tissues of oxygen, causing rapid cessation of cell behaviors.
3. Imaging
Note: For imaging, a confocal microscope is likely to be essential as the confocality removes most of the obscuring background caused by intense illumination of the pupal case.
<ol>
	<li>Adjust settings on the confocal to minimize the impact of illumination on pupal development and viability. To do so, strike a balance between the intensity of excitation and the sensitivity of collection. A typical configuration for imaging with the Leica SP5 used the resonant scanner (8,000 Hz), laser power set to 2% (10% transmittance of 20% power), pinhole set to 120 &#181;m, and line averaging set to 8. Settings will vary depending on experimental conditions.</li>
</ol>
Note: To resolve fine scale features 40X&#160;and 63X&#160;Oil immersion lenses (0.1 mm working distance) have also been successfully used in this method, though they limit the depth of focus.
4. Analysis
To analyze frames, z-stacks or movies import the data files to FIJI, which has effective tools for viewing, measuring, and modifying files for presentation14. For example time to complete mitosis was measured using the sampling interval and multidimensional image browser to step through frames while watching a cell from prophase to telophase. x-, y-,&#160;and z-dimensions can be measured using the measuring tool. For detailed instructions on the software and its use see: http://fiji.sc/Fiji.

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	<li>Raff, J. W., Jeffers, K., Huang, J. Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+roles+of+Fzy/Cdc20+and+Fzr/Cdh1+in+regulating+the+destruction+of+cyclin+B+in+space+and+time.">The roles of Fzy/Cdc20 and Fzr/Cdh1 in regulating the destruction of cyclin B in space and time.</a> J. Cell Biol. 157, 1139-1149 (2002).</li><li>Stramer, B., 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=Live+imaging+of+wound+inflammation+in+Drosophila+embryos+reveals+key+roles+for+small+GTPases+during+in+vivo+cell+migration.">Live imaging of wound inflammation in Drosophila embryos reveals key roles for small GTPases during in vivo cell migration.</a> J. Cell Biol. 168, 567-573 (2005).</li><li>Clark, I. B., Jarman, A. P., Finnegan, D. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Live+imaging+of+Drosophila+gonad+formation+reveals+roles+for+Six4+in+regulating+germline+and+somatic+cell+migration.">Live imaging of Drosophila gonad formation reveals roles for Six4 in regulating germline and somatic cell migration.</a> BMC Dev. Biol. 7, 52 (2007).</li><li>Fuger, P., Behrends, L. B., Mertel, S., Sigrist, S. J., Rasse, T. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Live+imaging+of+synapse+development+and+measuring+protein+dynamics+using+two-color+fluorescence+recovery+after+photo-bleaching+at+Drosophila+synapses.">Live imaging of synapse development and measuring protein dynamics using two-color fluorescence recovery after photo-bleaching at Drosophila synapses.</a> Nat. Protoc. 2, 3285-3298 (2007).</li><li>Siller, K. 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The authors have nothing to disclose.

To visualize, measure, and quantify features of dividing cells, required development of a simple preparation for observing mitosis in the living pupal wing of Drosophila&#160;by means of confocal analysis of His2AvGFP expressing cells. This method was used to document that the cell cycle in the pupal wing bears strong similarities to cell cycles in pseudostratified epithelia in that nuclei move to the apical surface of the epithelium where they enter mitosis. Following telophase, nuclei drop back into the epithe...

The vinegar fly, Drosophila melanogaster, is a well-established model for studying many aspects of biology. Drosophila research has a rich history of genetic experimentation that allows sophisticated forms of gene manipulation including expression, knockdown and mutation. With the advent of fluorescent protein labels, this repertoire has expanded to include studies of cells and proteins in living animals. The fly embryo is an excellent system for such studies as it is small and optically clear allowing deep, high-resolution imaging in vivo1-3. Other stages of fly development have proven to be less tractable, requiring anaesthetization4, dissection and short term culture5,6, or the creation of windows in the cuticle for imaging7,8. These manipulations usually compromise animal development in the long term or affect the animal in ways that limit imaging to short periods.
To study novel mutations in genes that resemble cell cycle regulators, it was essential to find an appropriate preparation to study the timing and fidelity of the cell cycle. Since most embryonic cell cycles are truncated (S-M or S-G2-M) and the mutants under study do not show defects until later stages, it was important to observe the cell cycle in pupal stage tissues. Epithelial cells in the pupa have a more typical G1-S-G2-M cell cycle and pupae of this stage are not capable of muscle movements9. The initial starting point for manipulations included intact whole pupae expressing Histone2AV-GFP. Despite the apparent opacity of the pupal case, this intact preparation proved to be excellent for long-term in vivo imaging. This technique is simple enough that undergraduate researchers routinely use it to study aspects of cell and developmental biology in Drosophila and yet the resolution is fine enough to allow discrimination of micrometer scale features. With this method, observations of events over hours, minutes, or seconds are possible simply by adjusting time series parameters. Videos using blue, green, yellow, orange, and red fluorescent proteins, or combinations of these, have been made. Importantly, if care is taken to minimize the laser intensity, even long-term imaging has no effect on development or viability of the animals.

<table border="0" cellpadding="0" cellspacing="0" width="573">
	<colgroup>
		<col />
		<col />
		<col />
		<col />
	</colgroup>
	<tbody>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Fly stuff fly pad</td>
			<td style="width:71px;">Genesee scientific</td>
			<td style="width:119px;">59-114</td>
			<td style="width:167px;">for fly anesthetization</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">CO2 gas</td>
			<td style="width:71px;">Airgas south</td>
			<td style="width:119px;">CD50</td>
			<td>For fly anesthetization</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Regulator</td>
			<td style="width:71px;">Airgas south</td>
			<td style="width:119px;"> </td>
			<td>CO2 regulator</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Fly vials</td>
			<td style="width:71px;">Genesee scientific</td>
			<td>32-113RLBF</td>
			<td>Fly culture</td>
		</tr>
		<tr height="105">
			<td height="105" style="height:105px;width:216px;">Drosophila lines:A9-Gal4 (Bl#8761), His2Av-GFP (Bl#5941), Sco/CyO HsCre (Bl#1092), UAS-ChRFP-Tub (Bl#25773)</td>
			<td style="width:71px;">Bloomington Stock center</td>
			<td></td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Glass bottom dishes #1 1/2</td>
			<td style="width:71px;">WillCo Wells BV</td>
			<td style="width:119px;"> </td>
			<td>For microscopy</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Thiodiethylene Glycol</td>
			<td style="width:71px;">Fluka</td>
			<td align="right" style="width:119px;">88559</td>
			<td>mountant</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Modeling clay</td>
			<td style="width:71px;">art supply store</td>
			<td style="width:119px;"> </td>
			<td>Support to position pupae against</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Paintbrushes</td>
			<td style="width:71px;">art supply store</td>
			<td style="width:119px;"> </td>
			<td>To manipulate flies</td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:216px;">Fine Forceps, Inox #5</td>
			<td style="width:71px;">Fine science tools</td>
			<td style="width:119px;">11252-20</td>
			<td>Dumont #5</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">computer</td>
			<td style="width:71px;">any</td>
			<td style="width:119px;"> </td>
			<td>8 Gb RAM for image/movie analysis</td>
		</tr>
		<tr height="46">
			<td height="46" style="height:47px;width:216px;">Fiji software</td>
			<td style="width:71px;"> </td>
			<td style="width:119px;">Free ware http://fiji.sc/Fiji</td>
			<td>Image analysis software</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Confocal microscope</td>
			<td style="width:71px;"> </td>
			<td style="width:119px;"> </td>
			<td>Any fast scanning confocal should be sufficient</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">20x dry, and 40x or 63x oil immersion lenses</td>
			<td style="width:71px;">any</td>
			<td style="width:119px;"> </td>
			<td>For imaging tissue, cellular and subcellular features</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Immersion oil (non fluorescent)</td>
			<td style="width:71px;"> </td>
			<td style="width:119px;"> </td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Stereo microscope</td>
			<td style="width:71px;">any</td>
			<td style="width:119px;"> </td>
			<td>For fly manipulation</td>
		</tr>
	</tbody>
</table>

imaging through the pupal case of drosophila melanogaster

The longstanding use of Drosophila as a model for cell and developmental biology has yielded an array of tools. Together, these techniques have enabled analysis of cell and developmental biology from a variety of methodological angles. Live imaging is an emerging method for observing dynamic cell processes, such as cell division or cell motility. Having isolated mutations in uncharacterized putative cell cycle proteins it became essential to observe mitosis in situ using live imaging. Most live imaging studies in Drosophila have focused on the embryonic stages that are accessible to manipulation and observation because of their small size and optical clarity. However, in these stages the cell cycle is unusual in that it lacks one or both of the gap phases. By contrast, cells of the pupal wing of Drosophila have a typical cell cycle and undergo a period of rapid mitosis spanning about 20 hr of pupal development. It is easy to identify and isolate pupae of the appropriate stage to catch mitosis in situ. Mounting intact pupae provided the best combination of tractability and durability during imaging, allowing experiments to run for several hours with minimal impact on cell and animal viability. The method allows observation of features as small as, or smaller than, fly chromosomes. Adjustment of microscope settings and the details of mounting, allowed extension of the preparation to visualize membrane dynamics of adjacent cells and fluorescently labeled proteins such as tubulin. This method works for all tested fluorescent proteins and can capture submicron scale features over a variety of time scales. While limited to the outer 20 &#181;m of the pupa with a conventional confocal microscope, this approach to observing protein and cellular dynamics in pupal tissues in vivo may be generally useful in the study of cell and developmental biology in these tissues.

Cells in pseudostratified epithelia, such as the developing Drosophila eye, or the ventricular layer of the developing vertebrate central nervous system, undergo nuclear movements, termed interkinetic nuclear migration, in time with the cell cycle. DNA replication occurs when nuclei are at or near the basal surface and cells enter mitosis when the nuclei reach the apical surface15,16. The pupal wing cells form a rapidly dividing monolayer epithelium during the first several hours after head eversion. ...

Watch this Scientific Journal Video about Imaging Through the Pupal Case of Drosophila melanogaster at JoVE.com

Imaging Through the Pupal Case of Drosophila melanogaster

This paper demonstrates the use of a fast scanning confocal microscope to image cell behavior directly through the puparium. By leaving the pupal case intact, this method allows observation and measurement of dynamic cell processes at a stage of Drosophila development that is difficult to study directly.

Imaging Through the Pupal Case of Drosophila melanogaster

The longstanding use of Drosophila as a model for cell and developmental biology has yielded an array of tools. Together, these techniques have enabled ...

imaging-through-the-pupal-case-of-drosophila-melanogaster

Research

JoVE Journal

Biology

13.3K Views.  University of Miami.  يوضح هذه الورقة استخدام المجهر متحد البؤر المسح السريع إلى سلوك الخلية صورة مباشرة من خلال puparium. من خلال ترك حالة العذراء سليمة، وهذا الأسلوب يسمح للمراقبة وقياس العمليات الحيوية في الخلية مرحلة من مراحل التنمية ذبابة الفاكهة التي يصعب در...

Video: Imaging Through the Pupal Case of Drosophila melanogaster

Dissection of Larval CNS in Drosophila Melanogaster

The central nervous system (CNS) of Drosophila larvae is complex and poorly understood.  One way to investigate the CNS is to use immunohistochemistry to examine the expression of various novel and marker proteins.  Staining of whole larvae is impractical because the tough cuticle prevents antibodies from penetrating inside the body cavity.  In order to stain these tissues it is necessary to dissect the animal prior to fixing and staining.  In this article we demonstrate how to dissect Drosophila larvae without damaging the CNS.  Begin by tearing the larva in half with a pair of fine forceps, and then turn the cuticle "inside-out" to expose the CNS.  If the dissection is performed carefully the CNS will remain attached to the cuticle.  We usually keep the CNS attached to the cuticle throughout the fixation and staining steps, and only completely remove the CNS from the cuticle just prior to mounting the samples on glass slides.  We also show some representative images of a larval CNS stained with Eve, a transcription factor expressed in a subset of neurons in the CNS.  The article concludes with a discussion of some of the practical uses of this technique and the potential difficulties that may arise.

In this article we demonstrate how to dissect the central nervous system from third instar Drosophila larvae.

The central nervous system (CNS) of Drosophila larvae is complex and poorly understood.  One way to investigate the CNS is to use immunohistochemistry to ...

Live Imaging Of Drosophila melanogaster Embryonic Hemocyte Migrations

Many studies address cell migration using in vitro methods, whereas the physiologically relevant environment is that of the organism itself. Here we present a protocol for the mounting of Drosophila melanogaster embryos and subsequent live imaging of fluorescently labeled hemocytes, the embryonic macrophages of this organism. Using the Gal4-uas system1 we drive the expression of a variety of genetically encoded, fluorescently tagged markers in hemocytes to follow their developmental dispersal throughout the embryo. Following collection of embryos at the desired stage of development, the outer chorion is removed and the embryos are then mounted in halocarbon oil between a hydrophobic, gas-permeable membrane and a glass coverslip for live imaging. In addition to gross migratory parameters such as speed and directionality, higher resolution imaging coupled with the use of fluorescent reporters of F-actin and microtubules can provide more detailed information concerning the dynamics of these cytoskeletal components.

Live Imaging Of Drosophila melanogaster Embryonic Hemocyte Migrations

Drosophila hemocytes disperse over the entirety of the developing embryo. This protocol demonstrates how to mount and image these migrations using embryos with fluorescently labelled hemocytes.

Many studies address cell migration using in vitro methods, whereas the physiologically relevant environment is that of the organism itself. Here we ...

Upright Imaging of Drosophila Embryos

Several well-known morphogenetic gradients and cellular movements occur along the dorsal/ventral axis of the Drosophila embryo. However, the current techniques used to view such processes are somewhat limited. The following protocol describes a new technique for mounting fixed and labeled Drosophila embryos for coronal viewing with confocal imaging. This method consists of embedding embryos between two layers of glycerin jelly mounting media, and imaging jelly strips positioned upright. The first step for sandwiching the embryos is to make a thin bedding of glycerin jelly on a slide. Next, embryos are carefully aligned on this surface and covered with a second layer of jelly. After the second layer is solidified, strips of jelly are cut and flipped upright for imaging. Alternatives are described for visualizing the embryos depending upon the type of microscope stand to be used. Since all cells along the dorsal-ventral axis are imaged within a single confocal Z-plane, our method allows precise measurement and comparison of fluorescent signals without photobleaching or light scattering common to 3D reconstructions of longitudinally mounted embryos.

Upright Imaging of Drosophila Embryos

Here we present a mounting protocol for stained Drosophila embryos in an upright position that allows imaging of cross-sections using Confocal microscopy.

Several well-known morphogenetic gradients and cellular movements occur along the dorsal/ventral axis of the Drosophila embryo. However, the current ...

Dissection of Oenocytes from Adult Drosophila melanogaster

In Drosophila melanogaster, as in other insects, a waxy layer on the outer surface of the cuticle, composed primarily of hydrocarbon compounds, provides protection against desiccation and other environmental challenges. Several of these cuticular hydrocarbon (CHC) compounds also function as semiochemical signals, and as such mediate pheromonal communications between members of the same species, or in some instances between different species, and influence behavior. Specialized cells referred to as oenocytes are regarded as the primary site for CHC synthesis. However, relatively little is known regarding the involvement of the oenocytes in the regulation of the biosynthetic, transport, and deposition pathways contributing to CHC output. Given the significant role that CHCs play in several aspects of insect biology, including chemical communication, desiccation resistance, and immunity, it is important to gain a greater understanding of the molecular and genetic regulation of CHC production within these specialized cells. The adult oenocytes of D. melanogaster are located within the abdominal integument, and are metamerically arrayed in ribbon-like clusters radiating along the inner cuticular surface of each abdominal segment. In this video article we demonstrate a dissection technique used for the preparation of oenocytes from adult D. melanogaster. Specifically, we provide a detailed step-by-step demonstration of (1) how to fillet prepare an adult Drosophila abdomen, (2) how to identify the oenocytes and discern them from other tissues, and (3) how to remove intact oenocyte clusters from the abdominal integument. A brief experimental illustration of how this preparation can be used to examine the expression of genes involved in hydrocarbon synthesis is included. The dissected preparation demonstrated herein will allow for the detailed molecular and genetic analysis of oenocyte function in the adult fruit fly.

Dissection of Oenocytes from Adult Drosophila melanogaster

In insects, the oenocytes produce cuticular hydrocarbon compounds. These compounds protect against desiccation and facilitate chemical communication. Here we demonstrate a dissection technique used to isolate the oenocytes from adult Drosophila melanogaster, and illustrate how this preparation can be utilized to study genes involved in hydrocarbon synthesis.

In Drosophila melanogaster, as in other insects, a waxy layer on the outer surface of the cuticle, composed primarily of hydrocarbon compounds, provides ...

Isolation of Drosophila melanogaster Testes

The testes of Drosophila melanogaster provide an important model for the study of stem cell maintenance and differentiation, meiosis, and soma-germline interactions. Testes are typically isolated from adult males 0-3 days after eclosion from the pupal case. The testes of wild-type flies are easily distinguished from other tissues because they are yellow, but the testes of white mutant flies, a common genetic background for laboratory experiments are similar in both shape and color to the fly gut. Performing dissection on a glass microscope slide with a black background makes identifying the testes considerably easier. Testes are removed from the flies using dissecting needles. Compared to protocols that use forceps for testes dissection, our method is far quicker, allowing a well-practiced individual to dissect testes from 200-300 wild-type flies per hour, yielding 400-600 testes. Testes from white flies or from mutants that reduce testes size are harder to dissect and typically yield 200-400 testes per hour.

Isolation of Drosophila melanogaster Testes

Drosophila melanogaster testes can be rapidly and efficiently isolated from adult males using dissecting needles. With practice, one can readily isolate in one or two days an amount of testes sufficient for the analysis of DNA or RNA by high throughput sequencing or more traditional molecular biology methods or of protein for antibody- or enzyme-based assays.

The testes of Drosophila melanogaster provide an important model for the study of stem cell maintenance and differentiation, meiosis, and soma-germline ...

Drosophila Pupal Abdomen Immunohistochemistry

The Drosophila pupal abdomen is an established model system for the study of epithelial morphogenesis and the development of sexually dimorphic morphologies 1-3. During pupation, which spans approximately 96 hours (at 25 &deg;C), proliferating populations of imaginal cells replace the larval epidermis to generate the adult abdominal segments. These imaginal cells, born during embryogenesis, exist as lateral pairs of histoblast nests in each abdominal segment of the larvae. Four pairs of histoblast nests give rise to the adult dorsal cuticle (anterior and posterior dorsal nests), the ventral cuticle (ventral nests) and the spiracles associated with each segment (spiracle nests) 4. Upon puparation, these diploid cells (distinguishable by size from the larger polyploid larval epidermal cells- LECs) begin a stereotypical process of proliferation, migration and replacement of the LECs. Various molecular and genetic tools can be employed to investigate the contributions of genetic pathways involved in morphogenesis of the adult abdomen. Ultimate adult phenotypes are typically analyzed following dissection of adult abdominal cuticles. However, investigation of the underlying molecular processes requires immunohistochemical analyses of the pupal epithelium, which present unique challenges. Temporally dynamic morphogenesis and the interactions of two distinct epithelial populations (larval and imaginal) generate a fragile tissue prone to excessive cell loss during dissection and subsequent processing. We have developed methods of dissection, fixation, mounting and imaging of the Drosophila pupal abdominem epithelium for immunohistochemical studies that generate consistent high quality samples suitable for confocal or standard fluorescent microscopy.

Drosophila Pupal Abdomen Immunohistochemistry

Antibody staining of the Drosophila pupae can enhance genetic analyses of adult abdominal developmental genetics. We present our protocol for dissection, fixation and antibody staining of staged Drosophila pupal abdomen.

The Drosophila pupal abdomen is an established model system for the study of epithelial morphogenesis and the development of sexually dimorphic ...

Measurement of Lifespan in Drosophila melanogaster

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 (<a href="http://sitemaker.umich.edu/pletcherlab/software">http://sitemaker.umich.edu/pletcherlab/software</a>). 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.

Measurement of Lifespan in Drosophila melanogaster

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 ...

Ex vivo Culture of Drosophila Pupal Testis and Single Male Germ-line Cysts: Dissection, Imaging, and Pharmacological Treatment

During spermatogenesis in mammals and in Drosophila melanogaster, male germ cells develop in a series of essential developmental processes. This includes differentiation from a stem cell population, mitotic amplification, and meiosis. In addition, post-meiotic germ cells undergo a dramatic morphological reshaping process as well as a global epigenetic reconfiguration of the germ line chromatin&#8212;the histone-to-protamine switch.
Studying the role of a protein in post-meiotic spermatogenesis using mutagenesis or other genetic tools is often impeded by essential embryonic, pre-meiotic, or meiotic functions of the protein under investigation. The post-meiotic phenotype of a mutant of such a protein could be obscured through an earlier developmental block, or the interpretation of the phenotype could be complicated. The model organism Drosophila melanogaster offers a bypass to this problem: intact testes and even cysts of germ cells dissected from early pupae are able to develop ex vivo in culture medium. Making use of such cultures allows microscopic imaging of living germ cells in testes and of germ-line cysts. Importantly, the cultivated testes and germ cells also become accessible to pharmacological inhibitors, thereby permitting manipulation of enzymatic functions during spermatogenesis, including post-meiotic stages.
The protocol presented describes how to dissect and cultivate pupal testes and germ-line cysts. Information on the development of pupal testes and culture conditions are provided alongside microscope imaging data of live testes and germ-line cysts in culture. We also describe a pharmacological assay to study post-meiotic spermatogenesis, exemplified by an assay targeting the histone-to-protamine switch using the histone acetyltransferase inhibitor anacardic acid. In principle, this cultivation method could be adapted to address many other research questions in pre- and post-meiotic spermatogenesis.

Ex vivo Culture of Drosophila Pupal Testis and Single Male Germ-line Cysts: Dissection, Imaging, and Pharmacological Treatment

This protocol describes the dissection and cultivation of intact testes and germ-line cysts from Drosophila melanogaster pupae. This method allows microscopic observation of spermatogenesis ex vivo. Furthermore, we describe a pharmacological assay of the effect of inhibitors on specific stages of germ-cell development in pupal testes.

During spermatogenesis in mammals and in Drosophila melanogaster, male germ cells develop in a series of essential developmental processes. This includes ...

Dissection and Mounting of Drosophila Pupal Eye Discs

The Drosophila melanogaster eye disc is a powerful system that can be used to study many different biological processes. It contains approximately 800 separate eye units, termed ommatidia1. Each ommatidium contains eight neuronal photoreceptors that develop from undifferentiated cells following the passage of the morphogenetic furrow in the third larval instar2. Following the sequential differentiation of the photoreceptors, non-neuronal cells develop, including cone and pigment cells, along with mechanosensory bristle cells3. Final differentiation processes, including the structured arrangement of all the ommatidial cell types, programmed cell death of undifferentiated cell types and rhodopsin expression, occurs through the pupal phase4-7. This technique focuses on manipulating the pupal eye disc, providing insight and instruction on how to dissect the eye disc during the pupal phase, which is inherently more difficult to perform than the commonly dissected third instar eye disc. This technique also provides details on immunostaining to allow the visualization of various proteins and other cell components.

Dissection and Mounting of Drosophila Pupal Eye Discs

The goal of this technique is to enable researchers to perform dissection, immunostaining and mounting of pupal eye discs from Drosophila melanogaster of any age.

The Drosophila melanogaster eye disc is a powerful system that can be used to study many different biological processes.  It contains approximately 800 ...

Maintenance of a Drosophila melanogaster Population Cage

Large quantities of DNA, RNA, proteins and other cellular components are often required for biochemistry and molecular biology experiments. The short life cycle of Drosophila enables collection of large quantities of material from embryos, larvae, pupae and adult flies, in a synchronized way, at a low economic cost. A major strategy for propagating large numbers of flies is the use of a fly population cage. This useful and common tool in the Drososphila community is an efficient way to regularly produce milligrams to tens of grams of embryos, depending on uniformity of developmental stage desired. While a population cage can be time consuming to set up, maintaining a cage over months takes much less time and enables rapid collection of biological material in a short period. This paper describes a detailed and flexible protocol for the maintenance of a Drosophila melanogaster population cage, starting with 1.5 g of harvested material from the previous cycle.

Maintenance of a Drosophila melanogaster Population Cage

This manuscript reports a detailed protocol for culturing, on a regular basis, a population of Drosophila melanogaster using a fly population cage.

Large quantities of DNA, RNA, proteins and other cellular components are often required for biochemistry and molecular biology experiments. The short life ...