This work was supported by grants to D.K. from the Medical Research Foundation of Oregon and from NIH/NINDS (NS047663). E.S. was supported by a training grant from the NIH (T32AG023477).

1. Fixing the Head on Collars and Embedding in Paraffin
Note: All of the steps in the fixation process should be done in a fume hood. Methylbenzoate, while not posing a health risk, has a highly distinct odor, which can be overwhelming if not handled in a fume hood.
<ol>
	<li>Before anesthetizing the flies, make up 50 mL of Carnoy solution by adding 15 mL of chloroform and 5 mL of glacial acetic acid to 30 mL of 99% ethanol (do not mix the chloroform and acetic acid). Pour it in a glass container with a flat bot...

<ol>
	<li>Alexander, A. G., Marfil, V., Li, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Use+of+Caenorhabditis+elegans+as+a+model+to+study+Alzheimer's+disease+and+other+neurodegenerative+diseases.">Use of Caenorhabditis elegans as a model to study Alzheimer's disease and other neurodegenerative diseases.</a> Front Genet. 5, 279 (2014).</li><li>Bonini, N. M., Fortini, M. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Human+neurodegenerative+disease+modeling+using+Drosophila.">Human neurodegenerative disease modeling using Drosophila.</a> Annu Rev Neurosci. 26, 627-656 (2003).</li><li>Calahorro, F., Ruiz-Rubio, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Caenorhabditis+elegans+as+an+experimental+tool+for+the+study+of+complex+neurological+diseases:+Parkinson's+disease,+Alzheimer's+disease+and+autism+spectrum+disorder.">Caenorhabditis elegans as an experimental tool for the study of complex neurological diseases: Parkinson's disease, Alzheimer's disease and autism spectrum disorder.</a> Invert Neurosci. 11, 73-83 (2011).</li><li>Chen, X., Barclay, J. W., Burgoyne, R. D., Morgan, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Using+C.+elegans+to+discover+therapeutic+compounds+for+ageing-associated+neurodegenerative+diseases.">Using C. elegans to discover therapeutic compounds for ageing-associated neurodegenerative diseases.</a> Chemistry Central Journal. 9, 65 (2015).</li><li>Gama Sosa, M. A., De Gasperi, R., Elder, G. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Modeling+human+neurodegenerative+diseases+in+transgenic+systems.">Modeling human neurodegenerative diseases in transgenic systems.</a> Hum Genet. 131, 535-563 (2012).</li><li>Jaiswal, M., Sandoval, H., Zhang, K., Bayat, V., Bellen, H. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Probing+mechanisms+that+underlie+human+neurodegenerative+diseases+in+Drosophila.">Probing mechanisms that underlie human neurodegenerative diseases in Drosophila.</a> Annu Rev Genet. 46, 371-396 (2012).</li><li>Konsolaki, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fruitful+research:+drug+target+discovery+for+neurodegenerative+diseases+in+Drosophila.">Fruitful research: drug target discovery for neurodegenerative diseases in Drosophila.</a> Expert Opin Drug Discov. 8, 1503-1513 (2013).</li><li>Kretzschmar, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Neurodegenerative+mutants+in+Drosophila:+a+means+to+identify+genes+and+mechanisms+involved+in+human+diseases.">Neurodegenerative mutants in Drosophila: a means to identify genes and mechanisms involved in human diseases.</a> Invert Neurosci. 5, 97-109 (2005).</li><li>Kretzschmar, D., 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=Swiss+cheese+et+allii,+some+of+the+first+neurodegenerative+mutants+isolated+in+Drosophila.">Swiss cheese et allii, some of the first neurodegenerative mutants isolated in Drosophila.</a> J Neurogenet. 23, 34-41 (2009).</li><li>Li, J., Le, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Modeling+neurodegenerative+diseases+in+Caenorhabditis+elegans.">Modeling neurodegenerative diseases in Caenorhabditis elegans.</a> Exp Neurol. 250, 94-103 (2013).</li><li>Prussing, K., Voigt, A., Schulz, J. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Drosophila+melanogaster+as+a+model+organism+for+Alzheimer's+disease.">Drosophila melanogaster as a model organism for Alzheimer's disease.</a> Mol Neurodegener. 8, (2013).</li><li>Wentzell, J., Kretzschmar, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Alzheimer's+disease+and+tauopathy+studies+in+flies+and+worms.">Alzheimer's disease and tauopathy studies in flies and worms.</a> Neurobiol Dis. 40, 21-28 (2010).</li><li>Ali, Y. O., Escala, W., Ruan, K., Zhai, R. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Assaying+locomotor,+learning,+and+memory+deficits+in+Drosophila+models+of+neurodegeneration.">Assaying locomotor, learning, and memory deficits in Drosophila models of neurodegeneration.</a> J Vis Exp. , (2011).</li><li>Barone, M. C., Bohmann, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Assessing+neurodegenerative+phenotypes+in+Drosophila+dopaminergic+neurons+by+climbing+assays+and+whole+brain+immunostaining.">Assessing neurodegenerative phenotypes in Drosophila dopaminergic neurons by climbing assays and whole brain immunostaining.</a> J Vis Exp. , e50339 (2013).</li><li>Dutta, S., Rieche, F., Eckl, N., Duch, C., Kretzschmar, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Glial+expression+of+Swiss-cheese+(SWS),+the+Drosophila+orthologue+of+Neuropathy+Target+Esterase,+is+required+for+neuronal+ensheathment+and+function.">Glial expression of Swiss-cheese (SWS), the Drosophila orthologue of Neuropathy Target Esterase, is required for neuronal ensheathment and function.</a> Dis Model Mech. , (2015).</li><li>Iijima, K., 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=Abeta42+mutants+with+different+aggregation+profiles+induce+distinct+pathologies+in+Drosophila.">Abeta42 mutants with different aggregation profiles induce distinct pathologies in Drosophila.</a> PLoS One. 3, e1703 (2008).</li><li>Krishnan, N., 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=Loss+of+circadian+clock+accelerates+aging+in+neurodegeneration-prone+mutants.">Loss of circadian clock accelerates aging in neurodegeneration-prone mutants.</a> Neurobiol Dis. 45, 1129-1135 (2012).</li><li>Liu, H., 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=Automated+rapid+iterative+negative+geotaxis+assay+and+its+use+in+a+genetic+screen+for+modifiers+of+Abeta(42)-induced+locomotor+decline+in+Drosophila.">Automated rapid iterative negative geotaxis assay and its use in a genetic screen for modifiers of Abeta(42)-induced locomotor decline in Drosophila.</a> Neurosci Bull. 31, 541-549 (2015).</li><li>Papanikolopoulou, K., Skoulakis, E. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Temporally+distinct+phosphorylations+differentiate+Tau-dependent+learning+deficits+and+premature+mortality+in+Drosophila.">Temporally distinct phosphorylations differentiate Tau-dependent learning deficits and premature mortality in Drosophila.</a> Hum Mol Genet. 24, 2065-2077 (2015).</li><li>Ping, Y., 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=Linking+abeta42-induced+hyperexcitability+to+neurodegeneration,+learning+and+motor+deficits,+and+a+shorter+lifespan+in+an+Alzheimer's+model.">Linking abeta42-induced hyperexcitability to neurodegeneration, learning and motor deficits, and a shorter lifespan in an Alzheimer's model.</a> PLoS Genet. 11, e1005025 (2015).</li><li>Sujkowski, A., Rainier, S., Fink, J. K., Wessells, R. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Delayed+Induction+of+Human+NTE+(PNPLA6)+Rescues+Neurodegeneration+and+Mobility+Defects+of+Drosophila+swiss+cheese+(sws)+Mutants.">Delayed Induction of Human NTE (PNPLA6) Rescues Neurodegeneration and Mobility Defects of Drosophila swiss cheese (sws) Mutants.</a> PLoS One. 10, e0145356 (2015).</li><li>Barone, M. C., Sykiotis, G. P., Bohmann, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Genetic+activation+of+Nrf2+signaling+is+sufficient+to+ameliorate+neurodegenerative+phenotypes+in+a+Drosophila+model+of+Parkinson's+disease.">Genetic activation of Nrf2 signaling is sufficient to ameliorate neurodegenerative phenotypes in a Drosophila model of Parkinson's disease.</a> Dis Model Mech. 4, 701-707 (2011).</li><li>Coulom, H., Birman, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chronic+exposure+to+rotenone+models+sporadic+Parkinson's+disease+in+Drosophila+melanogaster.">Chronic exposure to rotenone models sporadic Parkinson's disease in Drosophila melanogaster.</a> J Neurosci. 24, 10993-10998 (2004).</li><li>Navarro, J. A., 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=Analysis+of+dopaminergic+neuronal+dysfunction+in+genetic+and+toxin-induced+models+of+Parkinson's+disease+in+Drosophila.">Analysis of dopaminergic neuronal dysfunction in genetic and toxin-induced models of Parkinson's disease in Drosophila.</a> J Neurochem. 131, 369-382 (2014).</li><li>Heisenberg, M., B&#246;hl, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Isolation+of+anatomical+brain+mutants+of+Drosophila+by+histological+means.">Isolation of anatomical brain mutants of Drosophila by histological means.</a> Zeitschrift f&#252;r Naturforschung C. 34, 143 (1979).</li><li>Han, P. L., Meller, V., Davis, R. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Drosophila+brain+revisited+by+enhancer+detection.">The Drosophila brain revisited by enhancer detection.</a> J Neurobiol. 31, 88-102 (1996).</li><li>Lin, C. W., 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=Automated+in+situ+brain+imaging+for+mapping+the+Drosophila+connectome.">Automated in situ brain imaging for mapping the Drosophila connectome.</a> J Neurogenet. 29, 157-168 (2015).</li><li>Strausfeld, N. J., Sinakevitch, I., Vilinsky, I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+mushroom+bodies+of+Drosophila+melanogaster:+an+immunocytological+and+golgi+study+of+Kenyon+cell+organization+in+the+calyces+and+lobes.">The mushroom bodies of Drosophila melanogaster: an immunocytological and golgi study of Kenyon cell organization in the calyces and lobes.</a> Microsc Res Tech. 62, 151-169 (2003).</li><li>Bettencourt da Cruz, A., Wentzell, J., Kretzschmar, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Swiss+Cheese,+a+protein+involved+in+progressive+neurodegeneration,+acts+as+a+noncanonical+regulatory+subunit+for+PKA-C3.">Swiss Cheese, a protein involved in progressive neurodegeneration, acts as a noncanonical regulatory subunit for PKA-C3.</a> J Neurosci. 28, 10885-10892 (2008).</li><li>Bolkan, B. J., Kretzschmar, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Loss+of+Tau+results+in+defects+in+photoreceptor+development+and+progressive+neuronal+degeneration+in+Drosophila.">Loss of Tau results in defects in photoreceptor development and progressive neuronal degeneration in Drosophila.</a> Dev Neurobiol. 74, 1210-1225 (2014).</li><li>Cook, M., Mani, P., Wentzell, J. S., Kretzschmar, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Increased+RhoA+prenylation+in+the+loechrig+(loe)+mutant+leads+to+progressive+neurodegeneration.">Increased RhoA prenylation in the loechrig (loe) mutant leads to progressive neurodegeneration.</a> PLoS One. 7, e44440 (2012).</li><li>Wittmann, C. W., 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=Tauopathy+in+Drosophila:+neurodegeneration+without+neurofibrillary+tangles.">Tauopathy in Drosophila: neurodegeneration without neurofibrillary tangles.</a> Science. 293, 711-714 (2001).</li><li>Rasmuson, B., Green, M. M., Ewertson, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=QUALITATIVE+AND+QUANTITATIVE+ANALYSES+OF+EYE+PIGMENTS+AND+PTERIDINES+IN+BACK-MUTATIONS+OF+THE+MUTANT+wa+IN+DROSOPHILA+MELANOGASTER.">QUALITATIVE AND QUANTITATIVE ANALYSES OF EYE PIGMENTS AND PTERIDINES IN BACK-MUTATIONS OF THE MUTANT wa IN DROSOPHILA MELANOGASTER.</a> Hereditas. 46, 635-650 (1960).</li><li>Bettencourt da Cruz, A., 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=Disruption+of+the+MAP1B-related+protein+FUTSCH+leads+to+changes+in+the+neuronal+cytoskeleton,+axonal+transport+defects,+and+progressive+neurodegeneration+in+Drosophila.">Disruption of the MAP1B-related protein FUTSCH leads to changes in the neuronal cytoskeleton, axonal transport defects, and progressive neurodegeneration in Drosophila.</a> Mol Biol Cell. 16, 2433-2442 (2005).</li><li>Kretzschmar, D., Hasan, G., Sharma, S., Heisenberg, M., Benzer, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+swiss+cheese+mutant+causes+glial+hyperwrapping+and+brain+degeneration+in+Drosophila.">The swiss cheese mutant causes glial hyperwrapping and brain degeneration in Drosophila.</a> J Neurosci. 17, 7425-7432 (1997).</li><li>Dutta, S., Rieche, F., Eckl, N., Duch, C., Kretzschmar, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Glial+expression+of+Swiss+cheese+(SWS),+the+Drosophila+orthologue+of+neuropathy+target+esterase+(NTE),+is+required+for+neuronal+ensheathment+and+function.">Glial expression of Swiss cheese (SWS), the Drosophila orthologue of neuropathy target esterase (NTE), is required for neuronal ensheathment and function.</a> Dis Model Mech. 9, 283-294 (2016).</li><li>Davis, M. Y., 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=Glucocerebrosidase+Deficiency+in+Drosophila+Results+in+alpha-Synuclein-Independent+Protein+Aggregation+and+Neurodegeneration.">Glucocerebrosidase Deficiency in Drosophila Results in alpha-Synuclein-Independent Protein Aggregation and Neurodegeneration.</a> PLoS Genet. 12, e1005944 (2016).</li><li>Dias-Santagata, D., Fulga, T. A., Duttaroy, A., Feany, M. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Oxidative+stress+mediates+tau-induced+neurodegeneration+in+Drosophila.">Oxidative stress mediates tau-induced neurodegeneration in Drosophila.</a> J Clin Invest. 117, 236-245 (2007).</li><li>Kretzschmar, D., 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=Glial+and+neuronal+expression+of+polyglutamine+proteins+induce+behavioral+changes+and+aggregate+formation+in+Drosophila.">Glial and neuronal expression of polyglutamine proteins induce behavioral changes and aggregate formation in Drosophila.</a> Glia. 49, 59-72 (2005).</li><li>Li, Y., 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=A+Drosophila+model+for+TDP-43+proteinopathy.">A Drosophila model for TDP-43 proteinopathy.</a> Proc Natl Acad Sci U S A. 107, 3169-3174 (2010).</li></ol>

The authors have nothing to disclose.

The described method provides a means to quantify neurodegeneration in the brain of Drosophila. While other methods, like counting a specific cell type, can be used to identify neurodegeneration, the advantage of this method is that it can be applied more generally. Counting cells requires that these cells can be reliably identified using either a specific antibody or the expression of a cell-specific marker, which is not always available. Furthermore, it has been shown that dramatically different results can be...

With the increase in life expectancy, neurodegenerative diseases like Alzheimer&#39;s or Parkinson&#39;s have become an increasing health threat for the general population. According to the National Institutes of Health, 115 million people worldwide are predicted to be affected by dementia in 2050. Although significant progress has been made in identifying genes and risk factors involved in at least some of these diseases, for many of them, the underlying molecular mechanisms are still unknown or not well understood.
Simple invertebrate model organisms like Caenorhabditis elegans and Drosophila melanogaster offer a variety of experimental advantages to study the mechanisms of neurodegenerative diseases, including a short life cycle, large number of progeny, and the availability of well-established and sometimes unique genetic and molecular methods1-12. Furthermore, these organisms are amenable to unbiased interaction screens that can identify factors contributing to these diseases by their aggravating or ameliorating effects on neurodegenerative phenotypes.
Analyzing such genetic interactions and assessing aging effects requires quantitative protocols to detect neurodegeneration and to measure its severity. This assessment can be done relatively easily when measuring behavioral aspects in Drosophila, such as olfactory learning, negative geotaxis, or fast phototaxis, which provide a numeric performance value13-21. It is also possible to determine the effects on neuronal survival by counting neurons. However, this is only possible when focusing on a specific population that is clearly identifiable, like the dopaminergic neurons that are affected in PD, and even then, the results have been controversial22-24.
The protocol described here uses the collar method to perform paraffin serial sections, a method that was originally developed by Heisenberg and B&#246;hl, who used it to isolate anatomical brain mutants in Drosophila25. The use of the collar method has subsequently been adapted, including in cryosections, vibratome sections, and plastic sections26-28. Here, this method is employed to obtain serial sections of the entire fly head, which can then be used to measure the vacuoles that develop in flies with neurodegenerative phenotypes16,21,29-32. These measurements can be done in specific brain areas or can cover the entire brain; the latter approach allows one to identify even weak degenerative phenotypes, as observed during aging. Finally, when using the collars, up to 20 flies can be processed as one preparation, which is not only less time-consuming, but also allows for the analysis of control and experimental flies in the same preparation, minimizing artifacts due to slight changes in the preparation.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Name of the Reagent/Equipment</td>
			<td>Company</td>
			<td>Catalog Number</td>
			<td></td>
		</tr>
		<tr>
			<td>Collar</td>
			<td>Genesee Scientific</td>
			<td>TS 48-100</td>
			<td>We are using custom made collars that are made from one piece of metal instead of layers as the ones by Genesee. A discription to make collars can be found at http://flybrain.neurobio.arizona.edu/Flybrain/html/atlas/fluorescent/index.html&#160;</td>
		</tr>
		<tr>
			<td>Rubber ice cube tray for embedding</td>
			<td>Household store</td>
			<td></td>
			<td>The size can be made to fit by glueing in additional walls&#160;</td>
		</tr>
		<tr>
			<td>Crystallizing dish</td>
			<td>Fisher Scientific company</td>
			<td>08-762-3</td>
			<td></td>
		</tr>
		<tr>
			<td>Ether</td>
			<td>Fisher Scientific Company</td>
			<td>E138-1</td>
			<td></td>
		</tr>
		<tr>
			<td>Ethanol</td>
			<td>Decon Laboratories Inc.</td>
			<td>2701</td>
			<td></td>
		</tr>
		<tr>
			<td>Choloroform</td>
			<td>Fisher Scientific Company</td>
			<td>C298-500</td>
			<td></td>
		</tr>
		<tr>
			<td>Glacial Acetic Acid</td>
			<td>Fisher Scientific Company</td>
			<td>A38-212</td>
			<td></td>
		</tr>
		<tr>
			<td>Methylbenzoate</td>
			<td>Fisher Scientific Company</td>
			<td>M205-500</td>
			<td>Distinct Odor</td>
		</tr>
		<tr>
			<td>Use in fume hood</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Low Melting Point Paraffin Wax</td>
			<td>Fisher Scientific Company</td>
			<td>T565</td>
			<td>Make sure to keep extra melted in a 65&#176;C waterbath</td>
		</tr>
		<tr>
			<td>Microtome</td>
			<td>Leica Biosystems</td>
			<td>Reichert Jung 2040 Autocut</td>
			<td></td>
		</tr>
		<tr>
			<td>Microscope Slide</td>
			<td>Fisher Scientific Company</td>
			<td>12-550D</td>
			<td></td>
		</tr>
		<tr>
			<td>Microscope Cover Glass</td>
			<td>Fisher Scientific Company</td>
			<td>12-545-M</td>
			<td></td>
		</tr>
		<tr>
			<td>SafeClear</td>
			<td>Fisher Scientific Company</td>
			<td>314-629</td>
			<td>Three different containers for washes</td>
		</tr>
		<tr>
			<td>Vertical Staining Jar with Cover</td>
			<td>Ted Pella Inc.&#160;</td>
			<td>432-1</td>
			<td></td>
		</tr>
		<tr>
			<td>Permount</td>
			<td>Fisher Scientific Company</td>
			<td>SP15-500</td>
			<td></td>
		</tr>
		<tr>
			<td>Poly-L-lysine Solution</td>
			<td>Sigma Life Science</td>
			<td>P8290-500</td>
			<td></td>
		</tr>
	</tbody>
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mass histology to quantify neurodegeneration in drosophila

Progressive neurodegenerative diseases like Alzheimer&#39;s disease (AD) or Parkinson&#39;s disease (PD) are an increasing threat to human health worldwide. Although mammalian models have provided important insights into the underlying mechanisms of pathogenicity, the complexity of mammalian systems together with their high costs are limiting their use. Therefore, the simple but well-established Drosophila model-system&#160;provides an alternative for investigating the molecular pathways that are affected in these diseases. Besides behavioral deficits, neurodegenerative diseases are characterized by histological phenotypes such as neuronal death and axonopathy. To quantify neuronal degeneration and to determine how it is affected by genetic and environmental factors, we use a histological approach that is based on measuring the vacuoles in adult fly brains. To minimize the effects of systematic error and to directly compare sections from control and experimental flies in one preparation, we use the &#39;collar&#39; method for paraffin sections. Neurodegeneration is then assessed by measuring the size and/or number of vacuoles that have developed in the fly brain. This can either be done by focusing on a specific region of interest or by analyzing the entire brain by obtaining serial sections that span the complete head. Therefore, this method allows one to measure not only severe degeneration but also relatively mild phenotypes that are only detectable in a few sections, as occurs during normal aging.

Using the described method results in serial sections stained by the eye pigment33 that encompass the entire fly head. A part of this is shown in Figure 1B, where the sections from an individual head are shown from top to bottom. The sections from different flies are seen left to right in this example. To facilitate orientation and identification of the flies, an eyeless fly (sine oculis) is inserted as a marker at position 3 (arrow, Figure 1B<...

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Mass Histology to Quantify Neurodegeneration in Drosophila

Drosophila is widely used as a model system to study neurodegeneration. This protocol describes a method by which degeneration, as determined by vacuole formation in the brain, can be quantified. It also minimizes effects due to the experimental procedure by processing and sectioning control and experimental flies as one sample.

Mass Histology to Quantify Neurodegeneration in Drosophila

Progressive neurodegenerative diseases like Alzheimer&#39;s disease (AD) or Parkinson&#39;s disease (PD) are an increasing threat to human health ...

The overall goal of this procedure is to quantify Neurodegeneration in the Drosophila Brain, caused by a variety of factors including age, genetic modifications, or environmental influences, without the need for specific staining. This method is very useful in analyzing key questions in the field of neurodegenerative diseases. Such as what genes or environmental factors cause or contribute to these diseases?The main advantage of this method is that it avoids or minimizes systematic errors because control flies and experimental flies are treated as one sample. Generally, individuals new to this method may struggle, because it takes practice to ensure that the correct area of the brain is on the slide and to prevent damage that may occur during cutting. To begin, first use forceps to thread the subject flies by the neck into the collars.Align all the heads in the same orientation and ensure no damage occurs to the head or eyes. Include Eyeless Senoculus Flies at random, known positions so that the order of the flies can be easily identified in the sections. Additionally, if the fly strain of interest has light or white eyes, thread red eyed flies at intervals along the strip, to ensure sufficient pigment is present to stain the slide.Record the order of the flies, together with the collar number if more than one is used. Once a collar is finished, place it into Carnoy's solution for three point five to four hours. Perform a series of Ethanol, Methyl Benzoate, and Paraffin washes to prepare the fly tissue for embedding.Next, place the collars into a rubber ice cube tray, on per section. Gently pour molten paraffin over the collars, avoiding air bubbles and allow it to harden overnight. Remove the paraffin blocks containing the collars from the tray.Separate the paraffin block from the collar, using a razor blade. Gently breaking off the collar. The bodies will remain in the collar, while the heads will stay in the paraffin block.To section the tissue, first warm a heating plate to 50 degrees Celsius. Place any tools that will contact the wax, such as razor blades or metal mounting blocks onto the plate to warm. Determine the desired orientation for sectioning and then attach the paraffin segment to the mounting block by briefly melting it at the contact side.With a razor blade, trim the excess paraffin away from the fly heads, so that only a small row containing the embedded heads remains. Place the mounting block into the object holder of the Microtome, aligning the heads parallel to the edge of the blade. Cut seven micrometer sections and transfer the ribbon of sections to microscope slides.Place the slides on a heated plate at 37 degrees Celsius for about one minute, to allow the ribbon to expand. Remove excess water and then set the slides to dry further overnight. Once dry, remove the paraffin wax by placing the slides vertically in a tall slide staining jar, filled with Deparaffinization agent for 30 minutes to one hour.Repeat this wash three times. Finally, remove the slides from the jar and place two drops of embedding media onto each one. Cover the sections with a large cover slip and allow slides to dry for one to two days.Under low magnification on a fluorescence microscope, determine the orientation of the brain and focus on the region of interest. Once this region is identified, take the required images. Using imaging software, count the number of vacuoles per head.Measure vacuole size by selecting the vacuole of interest and determining the number of pixels covered. This image shows sections from different fly heads oriented left to right. From top to bottom, serial sections from the same fly head are visualized.The Eyeless Senoculus control fly is indicated by the arrow. Sections are stained by the naturally present fluorescent eye pigment which washes over the sections during cutting. Paraffin head sections from seven, 14, and 21 day old Swiss Cheese One flies, show a progressive age-related increase in vacuole number and area.This degeneration is quantifiable by counting the vacuoles and calculating the combined area and found to be significant. Similarly, in Wild Type flies, neurodegeneration was shown to occur with age. In examination of head sections of 10, 30, and 60 day Wild Type flies few to no vacuoles were seen to have formed in the 10 day condition.In the brains of the 30 day old individuals vacuoles were beginning to form. In the 60 day individuals, significantly more and larger area vacuoles were present. Once mastered, sections can be available for analysis within a week.When using this procedure, it's important to carefully record the order of the flies in the collar. To ensure you can identify them later on, after analysis. After watching this video, you should have a good understanding of how to prepare the sections and to quantify Neurodegeneration found in the Drosophila brain.

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Neuroscience

9.9K visualizações.  Oregon Health & Sciences University. The overall goal of this procedure is to quantify Neurodegeneration in the Drosophila Brain, caused by a variety of factors including age, genetic modifications, or environmental influences, without the need for specific staining. This method is very useful in analyzing key questions in the field of neurodegenerative diseases. Such as what genes or environmental factors cause or contribute to these diseases?The main advantage of this method is that it avoids or minimizes systematic err...