Wir möchten die Max-Planck-Gesellschaft für die Finanzierung unserer Forschung danken.

1. Vorbereitung der Respirometer <ol><li> Schneiden Sie die 1.000 ul Pipettenspitze mit einer Rasierklinge, um die Einführung der 50-ul Kapillar-Mikropipette zu ermöglichen, versuchen, die Pipettenspitze so gerade wie möglich zu erhalten. </li><li> Legen Sie ein Stück Schaumstoff in die Pipette und drücken Sie ihn in der Pipettenspitze. </li><li> Eine kleine Menge des CO 2 absorbierenden und enthalten es durch ein zweites Stück Schaumstoff. </li><li> Leim an der Stelle, wo die Mikropipette in die Pipettenspitze eingelegt. </li><li> Verlassen Sie die Respirometer über Nacht, damit der Leim trocknen. Eine schematische Darstellung eines Spiro ist in 1A gezeigt. </li></ol> 2. Herstellung der Messkammer <ol><li> Bereiten Sie die Kammer-Lösung durch Mischen von Wasser mit Eosin in einem Verhältnis, das im sichtbaren Einfärbung führen wird. </li><li> Gießen Sie die Eosin-/ Wasser-Lösung in die Kammer. </li><li> Beschriften Sie eine der Seiten der Kammer mit einer Zentimeter-Skala. </li></ol><ol><li> Beschriften Sie die einzelnen Respirometer mit einem Marker. </li><li> Anesthetize Fliegen mit einer anderen Methode zu CO 2 und legen 3-5 Fliegen des gewünschten Genotyps in jedem Respirometer. </li><li> Verschließen Sie die Respirometer dicht an der Spitze mit Plastilin Kitt. </li><li> Lassen Sie Fliegen von Betäubung für ca. 15 min zu erholen. </li><li> Bereiten Sie eine Respirometer ohne Fliegen, die als die atmosphärische Steuerung verwendet wird. </li></ol> 4. Durchführung des Experiments <ol><li> Hängen die Respirometer in der Kammer, indem ein 1,5 ml Eppendorf-Röhrchen Halter, der auf der Oberseite und der Unterseite an der Oberseite der Kammer offen ist. </li><li> Legen Respirometer mit der Mikropipette Spitze nach unten in die Kammer so dass die Spitze in die Farblösung eintauchen. </li><li> In Vaseline zwischen dem Deckelabdeckung und der Kammer, um stärkere Isolation von Temperatur-und Druck fluct bietenuations. </li><li> Schließen Sie den Deckel und lassen Sie das System für 15 Minuten ins Gleichgewicht. </li><li> Machen Sie ein Foto von der Kammer darauf achten, dass der Flüssigkeitsstand innerhalb der einzelnen Mikropipette sichtbar ist und so ist die Skala (siehe Beispiel in Abbildung 1B). </li><li> Nach 1-2 Stunden, nehmen Sie ein anderes Bild. </li><li> Als Experiment ist abgeschlossen, entfernen Sie die Fliegen aus Respirometer und wiegen, wenn gewünscht oder übertragen Sie sie zurück in das Fläschchen, wenn weitere benötigt. </li></ol> 5. Analyse der Ergebnisse <ol><li> Offene erfassten Bilder mit ImageJ Software 11. </li><li> Mit der Skala in jedem Bild, stellen Sie die Pixel-Skalierung in der Software. </li><li> Den Abstand (&amp;Dgr; d) daß die Flüssigkeit von einem bestimmten Referenzpunkt in den Bildern am Anfang (d1) aufgenommen und zurück Ende des Experiments (d2). Ein schematisches Beispiel ist in Fig. 1C gezeigt. </li><li> Berechnen der Menge an erzeugtem CO 2 (&amp;mgr; l / hr / Fliege) mit der Formel: </li></ol><img alt="Figur 1" fo:content-width="2in" src="/files/ftp_upload/51681/51681eq1.jpg" /> R = Radius der Mikropipette Rohr in cm &amp;Dgr; D = Abstand die Flüssigkeit in der Mikropipette von Testproben in Zentimetern gemessen bewegt &amp;Dgr; C = Abstand die Flüssigkeit in der Mikropipette der negativen Kontrollprobe (ohne entfernt) bewegt n = Anzahl der Fliegen verwendet h = Stunden

<ol>
	<li>Van Voorhies, W. A., Khazaeli, A. A., Curtsinger, J. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Testing+the+&amp;#34;rate+of+living&amp;#34;+model:+further+evidence+that+longevity+and+metabolic+rate+are+not+inversely+correlated+in+Drosophila+melanogaster.">Testing the &amp;#34;rate of living&amp;#34; model: further evidence that longevity and metabolic rate are not inversely correlated in Drosophila melanogaster.</a> J Appl Physiol. 97, 1915-1922 (2004).</li><li>Ross, R. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Age-specific+decrease+in+aerobic+efficiency+associated+with+increase+in+oxygen+free+radical+production+in+Drosophila+melanogaster.">Age-specific decrease in aerobic efficiency associated with increase in oxygen free radical production in Drosophila melanogaster.</a> Journal of Insect Physiology. 46, 1477-1480 (2000).</li><li>van Voorhies, W. A., Khazaeli, A. A., Curtsinger, J. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Selected+contribution:+long-lived+Drosophila+melanogaster.+lines+exhibit+normal+metabolic+rates.">Selected contribution: long-lived Drosophila melanogaster. lines exhibit normal metabolic rates.</a> J Appl Physiol. 95, 2605-2613 (2003).</li><li>Hulbert, A. J., 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=Metabolic+rate+is+not+reduced+by+dietary-restriction+or+by+lowered+insulin/IGF-1+signalling+and+is+not+correlated+with+individual+lifespan+in+Drosophila+melanogaster.">Metabolic rate is not reduced by dietary-restriction or by lowered insulin/IGF-1 signalling and is not correlated with individual lifespan in Drosophila melanogaster.</a> Experimental Gerontology. 39, 1137-1143 (2004).</li><li>Ueno, T., Tomita, J., Kume, S., Kume, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dopamine+modulates+metabolic+rate+and+temperature+sensitivity+in+Drosophila+melanogaster.">Dopamine modulates metabolic rate and temperature sensitivity in Drosophila melanogaster.</a> PLoS ONE. 7, (2012).</li><li>Takeuchi, 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=Changes+in+temperature+preferences+and+energy+homeostasis+in+dystroglycan+mutants.">Changes in temperature preferences and energy homeostasis in dystroglycan mutants.</a> Science. 323, 1740-1743 (2009).</li><li>Kucherenko, M. M., Marrone, A. K., Rishko, V. M., Magliarelli Hde, F., Shcherbata, H. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Stress+and+muscular+dystrophy:+a+genetic+screen+for+dystroglycan+and+dystrophin+interactors+in+Drosophila.+identifies+cellular+stress+response+components.">Stress and muscular dystrophy: a genetic screen for dystroglycan and dystrophin interactors in Drosophila. identifies cellular stress response components.</a> Developmental Biology. 352, 228-242 (2011).</li><li>Marrone, A. K., Kucherenko, M. M., Wiek, R., Gopfert, M. C., Shcherbata, H. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hyperthermic+seizures+and+aberrant+cellular+homeostasis+in+Drosophila+dystrophic.+muscles.">Hyperthermic seizures and aberrant cellular homeostasis in Drosophila dystrophic. muscles.</a> Scientific Reports. 1, 47 (2011).</li><li>Khazaeli, A. A., Van Voorhies, W., Curtsinger, J. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Longevity+and+metabolism+in+Drosophila+melanogaster:+genetic+correlations+between+life+span+and+age-specific+metabolic+rate+in+populations+artificially+selected+for+long+life.">Longevity and metabolism in Drosophila melanogaster: genetic correlations between life span and age-specific metabolic rate in populations artificially selected for long life.</a> Genetics. 169, 231-242 (2005).</li><li>Elia, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Energy+equivalents+of+CO2+and+their+importance+in+assessing+energy+expenditure+when+using+tracer+techniques.">Energy equivalents of CO2 and their importance in assessing energy expenditure when using tracer techniques.</a> The American Journal of Physiology. 260, (1991).</li><li>Schindelin, J., 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=Fiji:+an+open-source+platform+for+biological-image+analysis.">Fiji: an open-source platform for biological-image analysis.</a> Nature Methods. 9, 676-682 (2012).</li><li>Bharucha, K. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+epicurean+fly:+using+Drosophila+melanogaster.+to+study+metabolism.">The epicurean fly: using Drosophila melanogaster. to study metabolism.</a> Pediatric Research. 65, 132-137 (2009).</li><li>Rajan, A., Perrimon, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Of+flies+and+men:+insights+on+organismal+metabolism+from+fruit+flies.">Of flies and men: insights on organismal metabolism from fruit flies.</a> BMC Biology. 11, 38 (2013).</li></ol>

Wir haben nichts zu offenbaren.

In diesem Protokoll beschreiben wir eine kostengünstige und zuverlässige Methode zur Messung der CO 2-Produktion in Fliegen. Wir fanden, dass dieses Experiment ist einfach, schnell durchzuführen und erzeugt reproduzierbare Daten, die in Übereinstimmung mit anderen Studien, 1, 6, 9 ist. Das hier beschriebene Protokoll kann leicht geändert werden, um Budget und verfügbaren Materialien jedes möglichen Labor passen. Die Konstruktion jedes einzelnen Respirometers kann, solange die Kammer luftdich...

Die biochemischen Krebs-Zyklus erzeugt ATP durch Oxidation von Acetat aus Kohlenhydraten, Fetten und Proteinen produzieren CO 2 abgeleitet. In Drosophila, O 2-Eingang direkt mit CO 2-Ausstoß korreliert und spiegelt das Niveau des Stoffwechsels ein. So Messung der CO 2-Ausstoß ist erfolgreich in Studien zur Alterung und Stoffwechsel 2-5 Zusammenhang verwendet. Hier unser Labor zuvor entworfen Versuchsaufbauten modifiziert, so dass Messung von CO 2-Produktion in bis zu achtzehn Proben ohne jede Spezialausrüstung erfordern. Andere und wir haben auch bisher diese Methode, um Unterschiede in der Stoffwechselraten in den Fliegen, die einen Mangel in der Muskeldystrophie assoziierten Protein, Dystroglycan (Dg) 6-8 sind zu zeigen. O 2 für oxidativen Stoffwechsel verwendet wird, in CO 2, der als Atemwegs Abfall ausgestoßen wird, umgewandelt wird. Der Baution von Hand hergestellt Respirometer beschrieben, die zur Bestimmung der Rate der O 2-Verbrauch kann. Fliegen werden in einem versiegelten Behälter mit einer Substanz, die CO 2 absorbiert vertrieben werden, mit dem gasförmigen Phase wirksam eliminieren. Die Änderung des Gasvolumens (verminderte Druck) wird durch die Verdrängung des Fluids in einer Glaskapillare mit dem geschlossenen Spiro angebracht war, gemessen. Der Hauptvorteil dieses Verfahrens gegenüber anderen sind die Kosten. Frühere Studien haben CO 2-Produktion durch Drosophila mit Gasanalysatoren und technisch ausgereifte Systeme Respirometrie 1,9 gemessen. Trotz der komplexeren Geräten ist die Empfindlichkeit der hier beschriebenen Verfahren ähnlich berichteten Werten (Tabelle 1). Darüber hinaus haben mehrere andere Gruppen Varianten dieser Technik verwendet, um relative Stoffwechselraten in Drosophila 4-6 bestimmen. Daher kann dieser Assay verwendet werden, um verlässigen erzeugenle, relevant Drosophila Stoffwechsel ohne den Erwerb von Spezialgeräten, die Konfiguration für jedes Labor sein kann und für pädagogische Zwecke verwendet werden reproduzierbare Daten. Im allgemeinen ist die akzeptierten Techniken, um den Stoffwechsel des Organismus zu bestimmen, messen die CO 2 erzeugt, das O 2 verbraucht oder beides 3,4,9. Obwohl, kann angenommen werden, daß ein Äquivalent von O 2 erzeugt ein Äquivalent von CO 2 ist, das genaue Verhältnis von CO 2 erzeugt wird, ist abhängig von der Stoffwechselsubstrat 10 verwendet. So ist es, um die Stoffwechselrate in Energieeinheiten notwendig, genau zu bestimmen, zu messen, sowohl O 2 verbraucht und CO 2 erzeugt. Aus diesem Grund ist das hier beschriebene Verfahren besonders relevant Vergleich Unterschiede in CO 2-Produktion von Tieren und der Absolutwert. Unsere Technik integriert mehrere Tier CO 2-Produktion über einen Zeitraum von time (1-2 Stunden) und damit gibt eine durchschnittliche Aktivität der Tiere. Wenn es einen Grund zu glauben, dass die Versuchstiere weniger aktiv als bei den Kontrolltieren konnten die Mess verschiedenen Ebenen der Aktivität und nicht unbedingt Stoffwechsel widerspiegeln.

<table border="0" cellpadding="0" cellspacing="0" width="1126">
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:401px;">BlauBrand IntraMark 50&#181;l micropipettes</td>
			<td style="width:101px;">VWR</td>
			<td style="width:119px;">612-1413</td>
			<td style="width:505px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:401px;">Soda Lime</td>
			<td style="width:101px;">Wako&#160;</td>
			<td style="width:119px;">CDN6847</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:401px;">Eosine&#160;</td>
			<td style="width:101px;">Sigma&#160;</td>
			<td style="width:119px;">031M4359</td>
			<td>Any dye that can create visible colorization of liquid can be used</td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:401px;">Thin Layer Chromatorgaphy (TLC) Developing Chamber</td>
			<td style="width:101px;">VWR</td>
			<td>21432-761</td>
			<td>Any transparent glass chamber that can be closed with the lid</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Anesthetizer, Lull-A-Fly Kit</td>
			<td style="width:101px;">Flinn</td>
			<td>FB1438</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:401px;">Power Gel Glue</td>
			<td style="width:101px;">Pritt</td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:401px;">1 ml pipett tips</td>
			<td style="width:101px;">Any</td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:401px;">Foam&#160;</td>
			<td style="width:101px;">Any</td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Plaesticine Putty</td>
			<td style="width:101px;">Any</td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:401px;">Scalpel</td>
			<td style="width:101px;">Any</td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:401px;">Twezzers&#160;</td>
			<td style="width:101px;">Any</td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
	</tbody>
</table>

measurement of metabolic rate in drosophila using respirometry

Stoffwechselstörungen sind ein häufiges Problem, die die menschliche Gesundheit. Daher ist das Verständnis der Mechanismen, die den Stoffwechsel regulieren, ist eine entscheidende wissenschaftliche Aufgabe. Viele krankheitsverursachenden Gene in Menschen haben eine Fliege Homolog, so dass Drosophila ein gutes Modell, um Signalwege in der Entwicklung verschiedener Erkrankungen beteiligt zu studieren. Zusätzlich wird die Lenkbarkeit von Drosophila vereinfacht genetische Screens bei der Identifizierung neuer therapeutischer Targets, die den Stoffwechsel regulieren kann helfen. Um einen solchen Bildschirm führen eine einfache und schnelle Methode, um Änderungen in der Stoffwechselzustand entfernt ist notwendig, zu identifizieren. Im allgemeinen ist die Produktion von Kohlendioxid ein guter Indikator für die Substratoxidation und Energieaufwand die Bereitstellung von Informationen über die Stoffwechsellage. In diesem Protokoll führen wir eine einfache Methode, um CO 2-Ausstoß von Fliegen messen. Diese Technik kann möglicherweise helfen bei der Identifizierung von genetischen Störungen beeinflussen die Stoffwechselrate.

Um zu zeigen, dass die Methode ist empfindlich uns gemessenen CO 2-Produktion aus dem Wildtyp (Oregon R) männlich fliegt bei 18, 25, und 29 ° C und fliegt Mutante für Dg. Die Fliegen wurden bei 25 ° C erhöht und dann verschoben, um die Versuchstemperatur 5 Tage lang vor der Messung. Wie für diese Art ectothermic erwartet, die Menge an CO 2 erzeugt erhöhte Temperatur (Abbildung 2). Wir haben in der Vergangenheit gezeigt, dass eine zuckerfreie Diät reduziert...

Watch this Scientific Journal Video about Measurement of Metabolic Rate in Drosophila using Respirometry at JoVE.com

Measurement of Metabolic Rate in Drosophila using Respirometry

Stoffwechselstörungen gehören zu einer der häufigsten Erkrankungen des Menschen. Die genetisch manipulierbaren Modellorganismus D. melanogaster kann verwendet werden, um neue Gene, die den Stoffwechsel regulieren, zu identifizieren. Dieses Papier beschreibt eine relativ einfache Methode, die die Untersuchung der Stoffwechselrate in Fliegen durch die Messung ihrer CO 2-Produktion ermöglicht.

Messung der Stoffwechselrate in<em&gt; Drosophila</em&gt; Mit Respirationstest

Metabolic disorders are a frequent problem affecting human health. Therefore, understanding the mechanisms that regulate metabolism is a crucial ...

measurement-of-metabolic-rate-in-drosophila-using-respirometry

Research

JoVE Journal

Biology

Measurement of Metabolic Rate in Drosophila using Respirometry

19.4K Aufrufe.  Max Planck Institute for Biophysical Chemistry.  Stoffwechselstörungen gehören zu einer der häufigsten Erkrankungen des Menschen. Die genetisch manipulierbaren Modellorganismus D. melanogaster kann verwendet werden, um neue Gene, die den Stoffwechsel regulieren, zu identifizieren. Dieses Papier beschreibt eine relativ einfache Methode, die die Untersuchung der Stoffwechselrate in Fliegen durch die Messung ihrer CO 2-Produktion ermöglicht. 

Serie: Measurement of Metabolic Rate in Drosophila using Respirometry

High-resolution Measurement of Odor-Driven Behavior in Drosophila Larvae

Olfactory responses in Drosophila larvae have been traditionally studied in Petri dishes comprising a single peripheral odor source. In this behavioral paradigm, the experimenter usually assumes that the rapid diffusion of odorant molecules from the source leads to the creation of a stable gradient in the dish. To establish a quantitative correlation between sensory inputs and behavioral responses, it is necessary to achieve a more thorough characterization of the odorant stimulus conditions. In this video article, we describe a new method allowing the construction of odorant gradients with stable and controllable geometries. We briefly illustrate how these gradients can be used to screen for olfactory defects (full and partial anosmia) and to study more subtle features of chemotaxis behavior.

In this video article, we describe a new method allowing the construction of odorant gradients with stable and controllable geometries. We briefly illustrate how these gradients can be used to screen for olfactory defects (full and partial anosmia) and to study more subtle features of chemotaxis behavior.

Hochauflösende Messung von Odor-Driven Behavior in Drosophila-Larven

Olfactory responses in Drosophila larvae have been traditionally studied in Petri dishes comprising a single peripheral odor source. In this behavioral ...

Forschung

Biologie

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.

Messung der Lebensdauer in<em&gt; Drosophila melanogaster</em

Aging is a phenomenon that results in steady physiological deterioration in nearly all organisms in which it has been examined, leading to reduced ...

A High-throughput Method for Measurement of Glomerular Filtration Rate in Conscious Mice

The measurement of glomerular filtration rate (GFR) is the gold standard in kidney function assessment. Currently, investigators determine GFR by measuring the level of the endogenous biomarker creatinine or exogenously applied radioactive labeled inulin (3H or 14C). Creatinine has the substantial drawback that proximal tubular secretion accounts for ~50% of total renal creatinine excretion and therefore creatinine is not a reliable GFR marker. Depending on the experiment performed, inulin clearance can be determined by an intravenous single bolus injection or continuous infusion (intravenous or osmotic minipump). Both approaches require the collection of plasma or plasma and urine, respectively. Other drawbacks of radioactive labeled inulin include usage of isotopes, time consuming surgical preparation of the animals, and the requirement of a terminal experiment. Here we describe a method which uses a single bolus injection of fluorescein isothiocyanate-(FITC) labeled inulin and the measurement of its fluorescence in 1-2 &mu;l of diluted plasma. By applying a two-compartment model, with 8 blood collections per mouse, it is possible to measure GFR in up to 24 mice per day using a special work-flow protocol. This method only requires brief isoflurane anesthesia with all the blood samples being collected in a non-restrained and awake mouse. Another advantage is that it is possible to follow mice over a period of several months and treatments (i.e. doing paired experiments with dietary changes or drug applications). We hope that this technique of measuring GFR is useful to other investigators studying mouse kidney function and will replace less accurate methods of estimating kidney function, such as plasma creatinine and blood urea nitrogen.

Measurement of glomerular filtration rate (GFR) is the gold standard for kidney function assessment. Here we describe a high-throughput method which allows the determination of GFR in conscious mice by using a single bolus injection, determination of fluorescein isothiocyanate (FITC)-inulin in plasma and calculation of GFR by a two-phase exponential decay model.

Ein High-Throughput-Verfahren zur Messung der glomerulären Filtrationsrate in Conscious Mäuse

The measurement of  glomerular filtration rate (GFR) is the gold standard in kidney function  assessment. Currently, investigators determine GFR by ...

An Improved Method for Accurate and Rapid Measurement of Flight Performance in Drosophila

Drosophila has proven to be a useful model system for analysis of behavior, including flight. The initial flight tester involved dropping flies into an oil-coated graduated cylinder; landing height provided a measure of flight performance by assessing how far flies will fall before producing enough thrust to make contact with the wall of the cylinder. Here we describe an updated version of the flight tester with four major improvements. First, we added a &#34;drop tube&#34; to ensure that all flies enter the flight cylinder at a similar velocity between trials, eliminating variability between users. Second, we replaced the oil coating with removable plastic sheets coated in Tangle-Trap, an adhesive designed to capture live insects. Third, we use a longer cylinder to enable more accurate discrimination of flight ability. Fourth we use a digital camera and imaging software to automate the scoring of flight performance. These improvements allow for the rapid, quantitative assessment of flight behavior, useful for large datasets and large-scale genetic screens.

An Improved Method for Accurate and Rapid Measurement of Flight Performance in Drosophila

Here we describe a method for rapid and accurate measurement of flight performance in Drosophila, enabling high-throughput screening.

Ein verbessertes Verfahren für genaue und schnelle Messung der Flugleistung in<em&gt; Drosophila</em

Drosophila has proven to be a useful model system for analysis of behavior, including flight. The initial flight tester involved dropping flies into an ...

Measurement of Larval Activity in the Drosophila Activity Monitor

Drosophila larvae are used in many behavioral studies, yet a simple device for measuring basic parameters of larval activity has not been available. This protocol repurposes an instrument often used to measure adult activity, the TriKinetics Drosophila activity monitor (MB5 Multi-Beam Activity Monitor) to study larval activity. The instrument can monitor the movements of animals in 16 individual 8 cm glass assay tubes, using 17 infrared detection beams per tube. Logging software automatically saves data to a computer, recording parameters such as number of moves, times sensors were triggered, and animals&#8217; positions within the tubes. The data can then be analyzed to represent overall locomotion and/or position preference as well as other measurements. All data are easily accessible and compatible with basic graphing and data manipulation software. This protocol will discuss how to use the apparatus, how to operate the software and how to run a larval activity assay from start to finish.

Measurement of Larval Activity in the Drosophila Activity Monitor

This report describes a method for measuring Drosophila larval activity using the TriKinetics Drosophila Activity Monitor. The device employs infrared beams to detect movements of up to 16 individual animals. Data can be analyzed to represent motion parameters including rates and the positions of the animals within the assay chambers.

Die Messung der Aktivität in der Larven<em&gt; Drosophila</em&gt; Activity Monitor

Drosophila larvae are used in many behavioral studies, yet a simple device for measuring basic parameters of larval activity has not been available. This ...

Measurement and Analysis of Extracellular Acid Production to Determine Glycolytic Rate

Extracellular measurement of oxygen consumption and acid production is a simple and powerful way to monitor rates of respiration and glycolysis1. Both mitochondrial (respiration) and non-mitochondrial (other redox) reactions consume oxygen, but these reactions can be easily distinguished by chemical inhibition of mitochondrial respiration. However, while mitochondrial oxygen consumption is an unambiguous and direct measurement of respiration rate2, the same is not true for extracellular acid production and its relationship to glycolytic rate 3-6. Extracellular acid produced by cells is derived from both lactate, produced by anaerobic glycolysis, and CO2, produced in the citric acid cycle during respiration. For glycolysis, the conversion of glucose to lactate- + H+ and the export of products into the assay medium is the source of glycolytic acidification. For respiration, the export of CO2, hydration to H2CO3 and dissociation to HCO3- + H+ is the source of respiratory acidification. The proportions of glycolytic and respiratory acidification depend on the experimental conditions, including cell type and substrate(s) provided, and can range from nearly 100% glycolytic acidification to nearly 100% respiratory acidification 6. Here, we demonstrate the data collection and calculation methods needed to determine respiratory and glycolytic contributions to total extracellular acidification by whole cells in culture using C2C12 myoblast cells as a model.

Glycolysis is a defining metabolic marker in multiple biological systems. Monitoring glycolysis by measuring the extracellular flux of H+ is common, but requires correction to be quantitative and unambiguous. Here, we demonstrate how to gather and correct extracellular flux data to distinguish between respiratory and glycolytic sources of extracellular acidification.

Messung und Analyse von extrazellulären Säureproduktion zu ermitteln glykolytischen Rate

Extracellular measurement of oxygen consumption and acid production is a simple and powerful way to monitor rates of respiration and glycolysis1. Both ...

Measurement of Carbon Dioxide Production from Radiolabeled Substrates in Drosophila melanogaster

The power of Drosophila genetics is increasingly being applied to questions of hormone signaling and metabolism and to the development of models of human disease in this organism. Sensitive methods for measurements of parameters such as metabolic rates are needed to drive the understanding of physiology and disease in small animals such as the fruit fly. The method described here assesses fuel oxidation in small numbers of adult flies fed food containing trace amounts of 14C-labeled substrates such as glucose or fatty acid. After the feeding period and any additional experimental manipulations, flies are transferred to short tubes capped with mesh, which are then placed in glass vials containing KOH-saturated filter paper that traps exhaled, radiolabeled CO2 generated from oxidation of radiolabeled substrates as potassium bicarbonate, KHCO3. This radiolabeled bicarbonate is measured by scintillation counting. This is a quantitative, reproducible, and simple approach for the study of fuel oxidation. The use of radiolabeled glucose, fatty acids, or amino acids allows determination of the contribution of these different fuel sources to energy metabolism under different conditions such as feeding and fasting and in different genetic backgrounds. This complements other approaches used to measure in vivo energy metabolism and should further the understanding of metabolic regulation.

Measurement of Carbon Dioxide Production from Radiolabeled Substrates in Drosophila melanogaster

This paper describes a method for the measurement of fuel oxidation in Drosophila melanogaster in which trace amounts of specific radiolabeled metabolic substrates are fed to flies. The exhaled radiolabeled CO2 that is a produced from fuel oxidation is collected and measured.

Die Messung der Kohlendioxidproduktion von Radiolabeled Substrate in<em&gt; Drosophila melanogaster</em

The power of Drosophila genetics is increasingly being applied to questions of hormone signaling and metabolism and to the development of models of human ...

Mixed Primary Cultures of Murine Small Intestine Intended for the Study of Gut Hormone Secretion and Live Cell Imaging of Enteroendocrine Cells

The gut is the largest endocrine organ of the body, with hormone-secreting enteroendocrine cells located along the length of the gastrointestinal epithelium. Despite their physiological importance, enteroendocrine cells represent only a small fraction of the epithelial cell population and in the past, their characterization has presented a considerable challenge resulting in a reliance on cell line models. Here, we provide a detailed protocol for the isolation and culture of mixed murine small intestinal cells. These primary cultures have been used to identify the signaling pathways underlying the stimulation and inhibition of gut peptide secretion in response to a number of nutrients and neuropeptides as well as pharmacological agents. Furthermore, in combination with the use of transgenic fluorescent reporter mice, we have demonstrated that these primary cultures become a powerful tool for the examination of fluorescently-tagged enteroendocrine cells at the intracellular level, using methods such as patch clamping and single-cell calcium and cAMP-FRET imaging.

This protocol describes the isolation and culture of mixed murine small intestinal cells. These primary intestinal cultures enable the investigation of signaling pathways underlying gut peptide secretion using a number of techniques.

Gemischte Primärkulturen von Murine Duenndarm bestimmt zur Untersuchung von Gut Hormonausschüttung und Live Cell Imaging von enteroendokrinen Zellen

The gut is the largest endocrine organ of the body, with hormone-secreting enteroendocrine cells located along the length of the gastrointestinal ...

Measurement of Energy Metabolism in Explanted Retinal Tissue Using Extracellular Flux Analysis

High acuity vision is a heavily energy-consuming process, and the retina has developed several unique adaptations to precisely meet such demands while maintaining transparency of the visual axis. Perturbations to this delicate balance cause blinding illnesses, such as diabetic retinopathy. Therefore, the understanding of energy metabolism changes in the retina during disease is imperative to the development of rational therapies for various causes of vison loss. The recent advent of commercially-available extracellular flux analyzers has made the study of retinal energy metabolism more accessible. This protocol describes the use of such an analyzer to measure contributions to retinal energy supply through its two principle arms - oxidative phosphorylation and glycolysis - by quantifying changes in oxygen consumption rates (OCR) and extracellular acidification rates (ECAR) as proxies for these pathways. This technique is readily performed in explanted retinal tissue, facilitating assessment of responses to multiple pharmacologic agents in a single experiment. Metabolic signatures in retinas from animals lacking rod photoreceptor signaling are compared to wild-type controls using this method. A major limitation in this technique is the lack of ability to discriminate between light-adapted and dark-adapted energy utilization, an important physiologic consideration in retinal tissue.

This technique describes real time recording of oxygen consumption and extracellular acidification rates in explanted mouse retinal tissues using an extracellular flux analyzer.

Messung des Energiestoffwechsels in explantierten Netzhautgewebe extrazelluläre Flux-Analyse

High acuity vision is a heavily energy-consuming process, and the retina has developed several unique adaptations to precisely meet such demands while ...

High-Resolution Respirometry to Assess Bioenergetics in Cells and Tissues Using Chamber- and Plate-Based Respirometers

High-resolution respirometry (HRR) allows monitoring oxidative phosphorylation in real-time for analysis of individual cellular energy states and assessment of respiratory complexes using diversified substrate-uncoupler-inhibitor titration (SUIT) protocols. Here, the usage of two high-resolution respirometry devices is demonstrated, and a basic collection of protocols applicable for the analysis of cultured cells, skeletal and heart muscle fibers, and soft tissues such as the brain and liver are presented. Protocols for cultured cells and tissues are provided for a chamber-based respirometer and cultured cells for a microplate-based respirometer, both encompassing standard respiration protocols. For comparative purposes, CRISPR-engineered HEK293 cells deficient in mitochondrial translation causing multiple respiratory system deficiency are used with both devices to demonstrate cellular defects in respiration. Both respirometers allow for comprehensive measurement of cellular respiration with their respective technical merits and suitability dependent on the research question and model under study.

Assessing oxidative phosphorylation using high-resolution respirometers has become an integral part of the functional analysis of mitochondria and cellular energy metabolism. Here, we present protocols for the analysis of cellular energy metabolism using chamber and microplate-based high-resolution respirometers and discuss the key benefits of each device.