Die Autoren danken Dr. Le Trinh und Dr. Tobin für die großzügige Bereitstellung der α-Catenin: Citrin Angelschnur und Bill Jackman für die Erlaubnis, die Dreharbeiten in seinem Labor zu tun. Die Autoren erkennen die Finanzierungsquellen National Institutes of Health (Grants 5P20RR016463, 8P20GM103423 und R15AI094406) und USDA (Projekt # ME0-H-1-00517-13). Dieses Manuskript ist als Haupt Land- und Forstwirtschaft Experiment Station Veröffentlichungsnummer 3371 veröffentlicht.

HINWEIS: Alle Zebrafisch Pflegeprotokolle und die Experimente wurden in Übereinstimmung mit NIH-Richtlinien unter Institutional Animal Care und Verwenden Committee (IACUC) Protokoll A2012-11-03 geführt. 1. Zebrafisch Aufzucht bis 4 Tage nach der Befruchtung <ol><li> Sammeln AB Zebrafisch oder andere transgene Linien, innerhalb der ersten 3 Stunden nach der Befruchtung, wie in einem anderen Video 34 gezeigt. </li><li> Inkubieren 120 Eier in eine 15 cm Petrischalen mit 150 ml E3 Medien (5 mM NaCl; 0,17 mM KCl; 0,33 mM CaCl2; 0,33 mM MgCl 2, 2 mM HEPES; pH 6,8) mit Methylenblau (0,3 ug / ml final Konzentration) in einem 33 ° C Inkubator mit 12/12 Hell / Dunkel-Photoperiode. </li><li> Ersetzen Sie die Medien nach 6 Stunden mit E3 + PTU (1-Phenyl-2-thioharnstoff, 10 ug / ml Endkonzentration) und entfernen Sie die toten Eiern. </li><li> Inkubieren für 4 Tage bei 33 ° C, die Medien mit frischen E3 + PTU Austausch nach 2 Tagen. </li></ol> 2.Projektions Micro-Nadel Vorbereitung <ol><li> Ziehen Borosilikat Kapillare (OD 1,2 mm; 0,69 mm ID) in eine Mikronadel mit einem Nadelzieher mit den folgenden Einstellungen (550 Wärme; 0 Pull; 130 Velocity; 110 Time). HINWEIS: Die Einstellungen werden vom Filament variieren Filament ähnlich geformte Mikronadeln zu erhalten (siehe Abbildung 1) und muss neu eingestellt werden, wenn ein neues Filament eingebaut ist. </li><li> Füllen einer Mikronadel mit 3 &amp; mgr; l von 0,4 &amp; mgr; m-filtriert Phosphatpuffersalzlösung (PBS; 137 mM NaCl; 2,7 mM KCl; 10 mM Na 2 HPO 4; 1,8 mM KH 2 PO 4, pH 7,4) unter Verwendung einer 20 ul-Pipette Microloader Tipp. </li><li> Richten Sie das Mikro-Nadel auf einer Mikropipette Halter auf einem Mikromanipulator mit einem Druckinjektionssystem befestigt. Stellen Sie den Einspritzdruck auf 30 PSI und der Impulsdauer bei 30 ms. </li><li> Mit einer Petrischale mit destilliertem Wasser, senken Sie die Mikronadel, bis 1/5 der Nadel in das Wasser. Clip der Mikronadel with feinen Pinzette gerade unter dem Wasserspiegel. Bringen Sie die Mikronadel aus dem Wasser, und drücken Sie das Pedal mehrmals, bis ein Bolus erscheint. </li><li> Den Durchmesser des Bolus durch Absenken der Mikronadel auf einem Hämocytometer mit einem Tropfen des Typs A Sionsöl geschichtet. Stellen Sie die Impulsdauer, um die gewünschte Lautstärke zu erhalten (siehe Tabelle 1). </li><li> Stellen Sie den Gegendruck für den Bolus in Öl stabil bleiben (senken Sie den Druck, wenn der Bolus-Volumen erhöht und erhöht den Gegendruck, wenn der Bolus-Volumen nimmt ab). Notieren Sie sich die Pulsdauer für jede Mikronadel. </li><li> Entfernen Sie das PBS aus der Mikronadel durch Absaugen es mit Hilfe eines Microloader Pipettenspitze und vertreiben die übrig gebliebenen PBS, indem Sie es wieder auf dem Injektor und spiegeln die kontinuierliche Impulsschalter. Reservieren Sie jede Mikronadel. </li></ol> 3. Candida Vorbereitung <ol><li> Streak Candida albicans mit codonoptimierten dTomato, GFP, BFP, EOS oder Far verwandeltRot aus einem gefrorenen Lager (-80 ° C lagerfähig in 25% Glycerin) mit einer sterilen Holzstab auf eine Hefe peptine Dextrose (YPD) Agar-Platte (10 g / l Hefeextrakt, 20 g / l Pepton, 20 g / l Dextrose , 20 g / l Agar, autoklaviert und goss 25 ml in Petrischalen) und Inkubation über Nacht bei 30 ° C. </li><li> Wählen Sie eine Kolonie mit einer sterilen Holzdübel und impfen zu 5 ml YPD-Flüssigkeit (10 g / l Hefeextrakt, 20 g / l Pepton, 20 g / l Dextrose, autoklaviert und aseptisch in 5 ml in 16 x 150 mm Glaskultur aliquotiert Röhren). </li><li> Inkubieren über Nacht bei 30 ° C in einer Rollentrommel bei 60 Upm. </li><li> Sammeln Sie 1 ml C albicans-Kultur und den Transfer in ein 1,7 ml steriles Zentrifugenröhrchen. </li><li> Zentrifugieren bei 5.000 xg für ein paar Sekunden. Leeren Sie den Überstand und 1 ml sterilem PBS, gründlich vortexen. Wiederholen Sie dies zweimal. </li><li> Zählen Sie die Kolonien mit einer Zählkammer durch Verdünnung der 1 ml Lager 1: 1000 in sterilem PBS. </li></ol> 4. Einspritzen in Zebrafischdie Schwimmblase <ol><li> Erwärmen eines Injektionsform (2% Agarose) für 30 min in einem 33 ° C Inkubator. </li><li> Zum gewünschten Zeitpunkt, zu entfernen 100 der 150 ml E3 + PTU von der 15 cm Petrischale die Fische, die zum Einspritzen mit einer 25 ml Pipette ohne Absaugen keine Zebrafisch. </li><li> Anesthetize 4 dpf Zebrafisch durch Zugabe von 2 ml einer 4 mg / ml gepufferte Tricaine Methansulfonat Lager (TR), um die verbleibenden die 50 ml Medium (Endkonzentration 200 ug / ml), und warten Sie 15 Minuten. </li><li> Unter einem Binokular, wählen Sie Fisch mit einem aufgeblasenen Schwimmblase. Fisch kann zu diesem Zeitpunkt auch für homogene Phänotyp gescreent werden, wie beispielsweise neutrophile Verteilung in MPO: GFP-Leitung mit Epifluoreszenz Präpariermikroskop. </li><li> Verdünnen Sie die C albicans Lager aus seiner ursprünglichen Konzentration (Schritt 3.8) in 1,5 x 10 7 koloniebildenden Einheiten pro ml (cfu / ml) in PBS. </li><li> Übertragen Sie 30 Zebrafisch auf die Injektions Gericht mit einem Kunststoffüberführungsrohrtte und entfernen Sie das überschüssige Medien. </li><li> Mit einem Fischerdraht-Werkzeug (in ein Borosilikatglas Kapillaren 0,012 Zoll Durchmesser Angelschnur super geklebt), stellen Sie 3 Zeilen 10 Fische, indem Sie die Injektions Teller vertikal und orientieren die Fische vertikal. </li><li> Entfernen Sie die überzähligen Medien. </li><li> Das Röhrchen gründlich vortexen mit 1,5 × 10 7 cfu / ml C. albicans. </li><li> Füllen einer Mikronadel mit 3 ul C. albicans mit einem neuen Microloader Pipettenspitze und stellen Sie die Pulsdauer auf die entsprechende Einstellung (siehe Schritt 2.9). </li><li> Drehen Sie den Einspritz Gericht, um einen Winkel von 20 ° zwischen der Mikro-Nadel und der Kopf des Fisches zu machen, mit dem Ziel in Richtung der Rückseite des Schwimmblase (3A). </li><li> Drücken Sie den Mikro-Nadel in die Schwimmblase, um sicherzustellen, die Bohrung der Nadel in das Lumen, und drücken Sie das Pedal einmal. </li><li> Wiederholen Sie für jeden Fisch und übertragen zu einer Erholung Schale (25 ml E3 + PTU) durch Fluten der Schale mit einem E3d Entleerung in die stabile Schale. </li><li> Übertragen Sie weitere 30 Fische an der Einspritz Gericht. </li><li> Wiederholen Sie die Injektion mit einer neuen Mikro-Nadel mit gut gefüllten verwirbelt C. albicans. </li><li> Fertig durch Einspritzen der PBS-Kontrolle, wenn nötig, mit einem anderen Gericht Injektion zur Vermeidung von Verunreinigungen und Transfer zu einem separaten Recovery Gericht (Schritt 4.10). </li></ol> 5. Screening der Fisch zum Wunsch Inokulum <ol><li> Vorbereitung 40 ml 0,4% niedrigschmelz Agaroselösung (LMA) durch Zusatz von 160 mg des niedrigen Schmelz Agarose zu 40 ml E3, siedet durch Mikrowellenbehandlung bis zur Auflösung und Abkühlen auf 37 ° C. Fügen Sie 400 ul TR (Endkonzentration 200 ug / ml) nach dem Abkühlen. </li><li> Nach 30 Minuten Erholung, betäuben die Fische, wie beschrieben (Schritt 4.3 mit nur 1 ml TR in 25 ml E3 + PTU, Endkonzentration 200 ug / ml). </li><li> Übertragungs 30 Fisch (mit möglichst wenig Medien wie möglich), um 2 ml LMA in einem Gewichts Boot. </li><li> Saugen Sie einzelne Fische mit einer Transferpipette und Platte den Fisch mit 1 Tropfen LMA in einen 96-Loch-Bildplatte, nur mit den 10 x 6 zentralen Brunnen. </li><li> Wiederholen, bis alle Fische zu Bildschirm werden der Bildplatte geladen. </li><li> Lassen Sie das Medium erstarren bei Raumtemperatur für 5 min. </li><li> Positionieren Sie den Fisch auf ihrer Seite, dafür, dass sie in Kontakt mit dem Glasboden gibt. </li><li> Mit dem 20x-Objektiv auf einem umgekehrten Epifluoreszenz / Konfokalmikroskop und der entsprechenden Filter, notieren Sie die Anzahl der C albicans Hefe-Zellen in jeder Fischschwimmblase. </li><li> Wählen Sie den Fisch mit 15-25 Hefezellen in der Schwimmblase (oder gewünschte Inokulum) euthanize nicht ausgewählte Fisch (800 ug / ml TR in E3) und zurück gewählt Fische einer tiefen Petrischale mit 50 ml E3 + PTU durch Zugabe von 3 Tropfen E3 auf die Bildplatte ausgewählt Brunnen und Absaugen der Fisch mit einer Plastiktransferpipette. </li><li> Inkubiere bei 33 ° C für die gewünschte Dauer. </li></ol> 6. Visualisierung der Fisch-Post-Screening <ol><li> Zu der gewünschten Zeit, entfernen Sie 25 der 50 ml E3 + PTU Medien aus dem tiefen Petrischale die Fische Bild enthält. </li><li> Betäuben des Fisches wie beschrieben (Schritt 4.3 mit nur 1 ml TR in 25 ml E3 + PTU verbleibenden, Endkonzentration 200 ug / ml). </li><li> Platte der Fische in eine 96-Loch-Speicherfolie und Position entsprechend (Schritte von 5,3 bis 5,7). </li><li> Bild durch Scannen der konfokalen Mikroskopie mit den entsprechenden Laser und Emissionsfilter. Zuerst auf den Fisch im 4x Ziel unter differentiellem Interferenzkontrast (DIC) und Bilder der interessierenden Region unter Verwendung der 20X-Objektiv mit der konfokalen Laser im Scanning-Modus mit 2 &amp; mgr; s / Pixel Geschwindigkeit und 1024 x 600 Pixel-Seitenverhältnis zu erwerben. Erwerben Sie Z-Stapel mit 1 &amp; mgr; m-Schrittweite, die Anwendung Kalman-Filter-Modus von 3 Bildern. </li><li> Die Rückkehr zu einem tiefen Petrischale mit 50 ml E3 + PTU oder in individual Vertiefungen (24-well-Kulturschale, 3 ml E3 + PTU) und Inkubation bei 33 ° C. </li></ol> 7. Grundlagen zur Schwimmblase <ol><li> Füllen Sie einen 10-ml-Spritze mit Hochvakuumfett. </li><li> Vorbereiten einer 2% LMA (Schritt 5.3 mit 160 mg des niedrig schmelzender Agarose in 8 ml E3). </li><li> Zu der gewünschten Zeit, betäuben die Fische (Schritt 5.2). </li><li> Übertragungs 10 Fische einer 1,7 ml-Zentrifugenröhrchen mit 1 ml E3 und euthanize durch Zugabe von 200 &amp; mgr; l 4 mg / ml Tricaine (Endkonzentration 800 ug / ml) in das Zentrifugenröhrchen und Inkubieren für 15 min bei Raumtemperatur. </li><li> Bereiten Sie eine Imaging-Objektträger, indem Sie 4 Tropfen Vakuumfett in einem Quadrat, 1 cm voneinander entfernt auf einem Mikroobjekt (75 x 25 mm, Abbildung 2). </li><li> Platzieren Sie 2 Tropfen 2% LMA in der Mitte des Platzes. </li><li> Setzen Sie einen Fisch auf einem separaten Glasobjektträger unter einem Binokular und überprüfen, ob das Herz hat aufgehört zu schlagen, entfernen Sie das überschüssige Wasser. </li><li&gt; Mit einer feinen Pinzette sezieren die Schwimmblase durch die Aufrechterhaltung der Kopf in einer festen Position mit dem linken Pinzette und Herunterziehen des vorderen Darm mit den richtigen Pinzette (4A). </li><li> Nehmen Sie den Schwimmblase durch den pneumatischen Kanal mit den linken Pinzette und trennt sie vom Verdauungstrakt, und legen Sie sie in der Mitte der 2% LMA, bevor es erstarrt. </li><li> Legen Sie ein Deckglas (18 x 18 mm) an der Oberseite des bildgebenden Glasplatte und schieben Sie es, bis es die Vakuumfett sowie die LMA (Abbildung 2) berührt. </li><li> Bild innerhalb von 10 Minuten der Dissektion, wie in Schritt 6.4 beschrieben. Wiederholen Sie die Schritte 7,7-7,11 mit den anderen Fischen. </li></ol>

The authors have nothing to disclose.

Fortschritte und Grenzen der Schwimmblase Mikroinjektion Krankheitsmodell Das hier vorgestellte Modell ist eine Erweiterung des in Gratacap et al Schleimhaut Candidiasis Tauch Modell (2013). es fügt die Vorteile eines kontrollierten Infektion Zeit eine hoch reproduzierbare Infektionsdosis und damit eine verbesserte Effizienz. Wir zeigen hier neue Methoden, die nicht-invasive zeitliche Dokumentation der Infektionsdynamik im Detail als auch eine höhere Auflösung Ex-vivo-B...

Mucosal infections can lead to life threatening bloodstream infections due to the damage of the epithelial barrier, which allows pathogens access to the systemic environment1,2. In addition, mucosal infections can also cause significant immunopathology even when contained externally3-5. The commensal unicellular fungus Candida albicans is present in the majority of the population in the oral cavity and other mucosal sites6-9. Although normally contained by innate and adaptive immune responses, innate immune defects and medical interventions can lead to severe mucosal candidiasis. The assault on the epithelial barrier results in an increased risk of life threatening disseminated disease as well as immunopathology, as in the case of vulvo-vaginal candidiasis, additionally C. albicans colonization has been linked with lung immune homeostasis10,11. Disseminated candidiasis is now the fourth most common bloodstream infection in intensive care units12 and mortality as high as 40% makes it a major concern. Due to the increase in immunomodulatory treatments for patients with autoimmune diseases, cancer or organ transplants, it is imperative to understand the interaction between this pathogen and the mucosal immune compartment.
The majority of cell biological advances regarding C. albicans-cell interactions at the mucosal level come from in vitro13-15 and murine models16-18. Both these approaches have distinct advantages, but the ability to image live cells at high resolution in an intact host has limited the temporal and spatial characterization of the infection. For these studies, there is the need for an in vivo model where the interaction of pathogen, innate immune and epithelial cells can be visualized in an intact vertebrate host.
The zebrafish has emerged as an invaluable tool for the understanding of human disease, mainly due to its transparency and amenability to genetic manipulation. Cell and organ development have been imaged in exquisite detail, which has led to the description of novel immune cell behaviors, such as T cell behavior in the developing thymus19 or the battle between intracellular mycobacteria and phagocytes20-22. Recent work has described intestinal microbe-host interactions in zebrafish and shown that microbial colonization of the intestinal tract affects host intestinal physiology and resistance to other infections23,24. Furthermore, infection through the gut epithelium has been described for several pathogens.
In contrast to the intestinal tract, the swimbladder represents a more isolated and complementary mucosal model. This organ is an extension of the developing gut tube and forms anteriorly to the liver and pancreas25,26. It produces surfactant, mucus and antimicrobial peptides27,28 and anatomically, as well as ontogenetically, this organ is considered a homologue of the mammalian lung29,30. Since the pneumatic duct remains connected to the gut in the zebrafish, this allows for immersion infection to occur naturally. Remarkably, the only known naturally occurring infections of fish with Candida species are C. albicans infections in the swimbladder31. We recently described an experimental immersion infection model where C. albicans infects the swimbladder, and found that this infection recapitulates some of the hallmarks of C. albicans-epithelial interaction in vitro32,33. 
In the method presented here, the original immersion infection model is improved by directly injecting C. albicans into the swimbladder of 4 days post fertilization (dpf) zebrafish. This allows for precise temporal control of infection as well as a highly reproducible inoculum. It permits detailed intravital imaging, coupled with the versatility of the zebrafish model. As an example of what can be done with this method, we present the spatio-temporal dynamics of C. albicans growth along with neutrophil recruitment to the site of infection. Because zebrafish swimbladder tissue is challenging to image intravitally, we also present a rapid swimbladder dissection technique that improves fluorescence signal and microscopic resolution. These methods expand the toolbox for fungal, immunological, and aquaculture research as well as describing a novel infection route that may be translated to model other fungal, bacterial or viral infections of mucosal surfaces.

<table><tbody><tr><td>1.7 ml tubes</td><td>Axygen</td><td>MCT-175-C</td><td></td></tr><tr><td>Deep Petri dishes</td><td>Fisher Scientific</td><td>89107-632</td><td></td></tr><tr><td>Transfer pipettes</td><td>Fisher Scientific</td><td>13-711-7M</td><td></td></tr><tr><td>Yeast Extract</td><td>VWR Scientific</td><td>90000-726</td><td></td></tr><tr><td>Peptone</td><td>VWR Scientific</td><td>90000-264</td><td></td></tr><tr><td>Dextrose</td><td>Fisher Scientific</td><td>D16-1</td><td></td></tr><tr><td>Agar</td><td>VWR Scientific</td><td>90000-760</td><td></td></tr><tr><td>Fine tweezers (Dumont Dumoxel #5)</td><td>Fine Science Tools</td><td>11251-30</td><td></td></tr><tr><td>Wooden dowels</td><td>VWR Scientific</td><td>10805-018</td><td></td></tr><tr><td>Low melt agarose</td><td>VWR Scientific</td><td>12001-722</td><td></td></tr><tr><td>Flaming Brown micropipette puller</td><td>Sutter Instruments</td><td>P-97</td><td></td></tr><tr><td>Borosilicate capillary</td><td>Sutter Instruments</td><td>BF120-69-10</td><td></td></tr><tr><td>MPPI-3 injection system</td><td>Applied Scientific Instrumentation</td><td>MPPI-3</td><td></td></tr><tr><td>Back pressure unit</td><td>Applied Scientific Instrumentation</td><td>BPU</td><td></td></tr><tr><td>Micropipette holder kit</td><td>Applied Scientific Instrumentation</td><td>MPIP</td><td></td></tr><tr><td>Foot switch</td><td>Applied Scientific Instrumentation</td><td>FSW</td><td></td></tr><tr><td>Micromanipulator</td><td>Applied Scientific Instrumentation</td><td>MM33</td><td></td></tr><tr><td>Magnetic base</td><td>Applied Scientific Instrumentation</td><td>Magnetic Base</td><td></td></tr><tr><td>Tricaine methane sulfonate</td><td>Western Chemical Inc.</td><td>MS-222</td><td></td></tr><tr><td>Dissecting microscope</td><td>Olympus</td><td>SZ61 top SZX-ILLB2-100 base</td><td></td></tr><tr><td>Confocal microscope</td><td>Olympus</td><td>IX-81 with FV-1000 laser scanning confocal system</td><td></td></tr><tr><td>20X microscope objective</td><td>Olympus</td><td>UPlanSApo 20x/0.75</td><td></td></tr><tr><td>Roller drum</td><td>New Brunswick Scientific</td><td>TC-7</td><td></td></tr><tr><td>Microloader pipette tips</td><td>Eppendorf</td><td>930001007</td><td></td></tr><tr><td>Glass culture tubes (16 x 150 mm)</td><td>VWR Scientific</td><td>60825-435</td><td></td></tr><tr><td>NaCl</td><td>VWR Scientific</td><td>BDH4534-500GP</td><td></td></tr><tr><td>KCl</td><td>VWR Scientific</td><td>BDH4532-500GP</td><td></td></tr><tr><td>MgSO&lt;sub&gt;4&lt;/sub&gt;</td><td>VWR Scientific</td><td>BDH0246-500GP</td><td></td></tr><tr><td>HEPES (Corning)</td><td>VWR Scientific</td><td>BDH4520-500GP</td><td></td></tr><tr><td>Children clay (Play-Doh)</td><td>Hasbro</td><td></td><td></td></tr><tr><td>CaCl&lt;sub&gt;2&lt;/sub&gt;</td><td>Fisher Scientific</td><td>C69-500</td><td></td></tr><tr><td>Methylene blue</td><td>VWR Scientific</td><td>VW6276-0</td><td></td></tr><tr><td>PTU</td><td>Sigma</td><td>P7629-10G</td><td></td></tr><tr><td>Petri dishes</td><td>Fisher Scientific</td><td>FB0875712</td><td></td></tr><tr><td>Hemocytometer (Hausser scientific)</td><td>VWR Scientific</td><td>15170-172</td><td></td></tr><tr><td>Type A immersion oil</td><td>Blue Marble Products</td><td>51935</td><td></td></tr><tr><td>Centrifuge</td><td>Eppendorf</td><td>5424</td><td></td></tr><tr><td>Vortex Genie</td><td>VWR Scientific</td><td>14216-184</td><td></td></tr><tr><td>Agarose (Lonza)</td><td>VWR Scientific</td><td>12001-870</td><td></td></tr><tr><td>Na&lt;sub&gt;2&lt;/sub&gt;HPO&lt;sub&gt;4&lt;/sub&gt;</td><td>Fisher Scientific</td><td>S374-500</td><td></td></tr><tr><td>KH&lt;sub&gt;2&lt;/sub&gt;PO&lt;sub&gt;4&lt;/sub&gt;</td><td>Fisher Scientific</td><td>P285-500</td><td></td></tr><tr><td>Fishing wire</td><td>Stren</td><td></td><td></td></tr><tr><td>96 well imaging plate (Sensoplate)</td><td>Greiner Bio-One</td><td>655892</td><td></td></tr><tr><td>High vacuum grease (Dow Corning)</td><td>VWR Scientific</td><td>59344-055</td><td></td></tr><tr><td>Microslide (25 x 75 mm)</td><td>VWR Scientific</td><td>48300-025</td><td></td></tr><tr><td>Cover slips (18 x 18 mm), No 1.5</td><td>VWR Scientific</td><td>48366-045</td><td></td></tr><tr><td>15 cm Petri dish (Olympus plastics)</td><td>Genesee Scientific</td><td>32-106</td><td></td></tr><tr><td>Glycerol (EMD chemicals)</td><td>VWR Scientific</td><td>EMGX0185-5</td><td></td></tr><tr><td>24-well culture dish (Olympus plastics)</td><td>Genesee Scientific</td><td>25-107</td><td></td></tr><tr><td>Weight boats (8.9 cm)</td><td>VWR Scientific</td><td>89106-766</td><td></td></tr></tbody></table>

modeling mucosal candidiasis in larval zebrafish by swimbladder injection

Frühe Verteidigung gegen Krankheitserreger Schleimhaut besteht sowohl eine Epithelbarriere und angeborenen Immunzellen. Die immunocompetency von beiden, und ihre Zwischenverbindung, an erster Stelle stehen für den Schutz vor Infektionen. Die Wechselwirkungen von Epithelzellen und Zellen des angeborenen Immunsystems mit einem Pathogen besten in vivo, wo komplexe Verhalten entfaltet über Zeit und Raum untersucht. Allerdings sind bestehende Modelle nicht für den einfachen Raum-Zeit-Bildgebung der Kampf mit Krankheitserregern an der Schleimhautniveau ermöglichen. Die hier entwickelten Modell erstellt eine Schleimhaut-Infektion durch direkte Injektion des Pilzpathogen, Candida albicans, in die Schwimmblase der jugendlichen Zebrafisch. Die daraus resultierende Infektion ermöglicht hochauflösende Bildgebung von epithelialen und angeborenen Immunzellverhaltens in der gesamten Entwicklung der Mucosal Disease. Die Vielseitigkeit dieser Methode ermöglicht die Abfrage des Host, um die detaillierte Abfolge der Ereignisse, die zu Immun pH-Sondeagocyte Rekrutierung und die Rollen von bestimmten Zelltypen und molekulare Signalwege in Schutz zu untersuchen. Darüber hinaus kann das Verhalten des Erregers als Funktion der Immunangriff gleichzeitig unter Verwendung fluoreszierende Protein exprimierenden C. abzubildenden albicans. Erhöhte räumliche Auflösung der Wirt-Pathogen-Interaktion ist auch möglich, mit dem beschriebenen schnellen Schwimmblase Dissektionstechnik. Die hier beschriebene Schleimhaut-Infektionsmodell ist einfach und sehr gut reproduzierbar, so dass es ein wertvolles Werkzeug für die Untersuchung der Schleimhautinfektionen. Dieses System kann auch allgemein übersetzbar andere Schleimhautpathogene, wie beispielsweise mykobakteriellen, bakterielle oder virale Keime, die normalerweise durch epitheliale Oberflächen infizieren.

Mikroinjektion in der hinteren Schwimmblase Die hier präsentierten experimentellen Methode beschreibt die Injektion von einem konsistenten Dosis C. albicans Hefezellen in der Schwimmblase von 4 dpf Zebrafisch. Frühere Arbeiten mit der Immersions Modell schlägt vor, dass der Schwimmblase Immunantwort auf C. albicans ähnelt Säugerschleimhaut Candidiasis 32. Hier zeigen wir eine modifizierte Infektionsmethode, die einfacher, reproduzierbare und schnelle ist; mehre...

Watch this Scientific Journal Video about Modeling Mucosal Candidiasis in Larval Zebrafish by Swimbladder Injection at JoVE.com

Modeling Mucosal Candidiasis in Larval Zebrafish by Swimbladder Injection

In vivo spatio-temporal interactions of pathogen and immune defenses at the mucosal level are not easily imaged in existing vertebrate hosts. The method presented here describes a versatile platform to study mucosal candidiasis in live vertebrates using the swimbladder of the juvenile zebrafish as an infection site.

Modellierung Mucosal Candidiasis in Zebrafisch-Larven von Schwimmblase Injection

Early defense against mucosal pathogens consists of both an epithelial barrier and innate immune cells. The immunocompetency of both, and their ...

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Universidad de Cartagena UDEC

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JoVE Journal

Immunology and Infection

10.1K Aufrufe.  University of Maine. In vivo spatio-temporal interactions of pathogen and immune defenses at the mucosal level are not easily imaged in existing vertebrate hosts. The method presented here describes a versatile platform to study mucosal candidiasis in live vertebrates using the swimbladder of the juvenile zebrafish as an infection site.

Serie: Modeling Mucosal Candidiasis in Larval Zebrafish by Swimbladder Injection

Non-invasive Imaging of Disseminated Candidiasis in Zebrafish Larvae

Disseminated candidiasis caused by the pathogen Candida albicans is a clinically important problem in hospitalized individuals and is associated with a 30 to 40% attributable mortality6. Systemic candidiasis is normally controlled by innate immunity, and individuals with genetic defects in innate immune cell components such as phagocyte NADPH oxidase are more susceptible to candidemia7-9. Very little is known about the dynamics of C. albicans interaction with innate immune cells in vivo. Extensive in vitro studies have established that outside of the host C. albicans germinates inside of macrophages, and is quickly destroyed by neutrophils10-14. In vitro studies, though useful, cannot recapitulate the complex in vivo environment, which includes time-dependent dynamics of cytokine levels, extracellular matrix attachments, and intercellular contacts10, 15-18. To probe the contribution of these factors in host-pathogen interaction, it is critical to find a model organism to visualize these aspects of infection non-invasively in a live intact host. 
The zebrafish larva offers a unique and versatile vertebrate host for the study of infection. For the first 30 days of development zebrafish larvae have only innate immune defenses2, 19-21, simplifying the study of diseases such as disseminated candidiasis that are highly dependent on innate immunity. The small size and transparency of zebrafish larvae enable imaging of infection dynamics at the cellular level for both host and pathogen. Transgenic larvae with fluorescing innate immune cells can be used to identify specific cells types involved in infection22-24. Modified anti-sense oligonucleotides (Morpholinos) can be used to knock down various immune components such as phagocyte NADPH oxidase and study the changes in response to fungal infection5. In addition to the ethical and practical advantages of using a small lower vertebrate, the zebrafish larvae offers the unique possibility to image the pitched battle between pathogen and host both intravitally and in color. 
The zebrafish has been used to model infection for a number of human pathogenic bacteria, and has been instrumental in major advances in our understanding of mycobacterial infection3, 25. However, only recently have much larger pathogens such as fungi been used to infect larva5, 23, 26, and to date there has not been a detailed visual description of the infection methodology. Here we present our techniques for hindbrain ventricle microinjection of prim25 zebrafish, including our modifications to previous protocols. Our findings using the larval zebrafish model for fungal infection diverge from in vitro studies and reinforce the need to examine the host-pathogen interaction in the complex environment of the host rather than the simplified system of the Petri dish5.

The rapid development, small size and transparency of zebrafish are tremendous advantages for the study of innate immune control of infection1-4. Here we demonstrate techniques for infecting zebrafish larvae using the fungal pathogen Candida albicans by microinjection, methodology recently used to implicate phagocyte NADPH oxidase activity in control of fungal dimorphism5.

Nicht-invasive Bildgebung von disseminierter Candidiasis in Zebrafischlarven

Disseminated candidiasis caused by the pathogen Candida albicans is a clinically important problem in hospitalized individuals and is associated with a 30 ...

Forschung

Immunologie und Infektion

Establishment of Larval Zebrafish as an Animal Model to Investigate Trypanosoma cruzi Motility In Vivo

Chagas disease is a parasitic infection caused by Trypanosoma cruzi, whose motility is not only important for localization, but also for cellular binding and invasion. Current animal models for the study of T. cruzi allow limited observation of parasites in vivo, representing a challenge for understanding parasite behavior during the initial stages of infection in humans. This protozoan has a flagellar stage in both vector and mammalian hosts, but there are no studies describing its motility in vivo.The objective of this project was to establish a live vertebrate zebrafish model to evaluate T. cruzi motility in the vascular system. Transparent zebrafish larvae were injected with fluorescently labeled trypomastigotes and observed using light sheet fluorescence microscopy (LSFM), a noninvasive method to visualize live organisms with high optical resolution. The parasites could be visualized for extended periods of time due to this technique&#39;s relatively low risk of photodamage compared to confocal or epifluorescence microscopy. T. cruzi parasites were observed traveling in the circulatory system of live zebrafish in different-sized blood vessels and the yolk. They could also be seen attached to the yolk sac wall and to the atrioventricular valve despite the strong forces associated with heart contractions. LSFM of T. cruzi-inoculated zebrafish larvae is a valuable method that can be used to visualize circulating parasites and evaluate their tropism, migration patterns, and motility in the dynamic environment of the cardiovascular system of a live animal.

Establishment of Larval Zebrafish as an Animal Model to Investigate Trypanosoma cruzi Motility In Vivo

In this protocol, fluorescently labeled T. cruzi&#160;were injected into transparent zebrafish larvae, and parasite motility was observed in vivo using light sheet fluorescence microscopy.

Gründung der Larven Zebrafisch als Tier-Modell zu untersuchen Trypanosomen Trypanosoma Motilität In Vivo

Chagas disease is a parasitic infection caused by Trypanosoma cruzi, whose motility is not only important for localization, but also for cellular binding ...

Entwicklungsbiologie

Deciphering and Imaging Pathogenesis and Cording of Mycobacterium abscessus in Zebrafish Embryos

Zebrafish (Danio rerio) embryos are increasingly used as an infection model to study the function of the vertebrate innate immune system in host-pathogen interactions.&#160;The ease of obtaining large numbers of embryos, their accessibility due to external development, their optical transparency as well as the availability of a wide panoply of genetic/immunological tools and transgenic reporter line collections, contribute to the versatility of this model.&#160;In this respect, the present manuscript describes the use of zebrafish as an&#160;in vivo&#160;model system to investigate the chronology of Mycobacterium abscessus infection. This human pathogen can exist either as smooth (S) or rough (R) variants, depending on cell wall composition, and their respective virulence can be imaged and compared in zebrafish embryos and larvae. Micro-injection of either S or R fluorescent variants directly in the blood circulation via the caudal vein, leads to chronic or acute/lethal infections, respectively. This biological system allows high resolution visualization and analysis of the role of mycobacterial cording in promoting abscess formation. In addition, the use of fluorescent bacteria along with transgenic zebrafish lines harbouring fluorescent macrophages produces a unique opportunity for multi-color imaging of the host-pathogen interactions. This article describes detailed protocols for the preparation of homogenous M. abscessus inoculum and for intravenous injection of zebrafish embryos for subsequent fluorescence imaging of the interaction with macrophages. These techniques open the avenue to future investigations involving mutants defective in cord formation and are dedicated to understand how this impacts on M. abscessus pathogenicity in a whole vertebrate.

Deciphering and Imaging Pathogenesis and Cording of Mycobacterium abscessus in Zebrafish Embryos

Optically transparent zebrafish embryos are widely used to study and visualize in real time the interactions between pathogenic microorganisms and the innate immune cells. Micro-injection of Mycobacterium abscessus, combined with fluorescence imaging, is used to scrutinize essential pathogenic features such as cord formation in zebrafish embryos.

Entschlüsselung und Imaging Pathogenese und Cording von<em&gt; Mycobacterium abscessus</em&gt; In Zebrafischembryonen

Zebrafish (Danio rerio) embryos are increasingly used as an infection model to study the function of the vertebrate innate immune system in host-pathogen ...

Development of a Larval Zebrafish Infection Model for Clostridioides difficile

Clostridioides difficile infection (CDI) is considered to be one of the most common healthcare-associated gastrointestinal infections in the United States. The innate immune response against C. difficile has been described, but the exact roles of neutrophils and macrophages in CDI are less understood. In the current study, Danio rerio (zebrafish) larvae are used to establish a C. difficile infection model for imaging the behavior and cooperation of these innate immune cells in vivo. To monitor C. difficile, a labeling protocol using a fluorescent dye has been established. A localized infection is achieved by microinjecting labeled C. difficile, which actively grows in the zebrafish intestinal tract and mimics the intestinal epithelial damage in CDI. However, this direct infection protocol is invasive and causes microscopic wounds, which can affect experimental results. Hence, a more noninvasive microgavage protocol is described here. The method involves delivery of C. difficile cells directly into the intestine of zebrafish larvae by intubation through the open mouth. This infection method closely mimics the natural infection route of C. difficile.

Development of a Larval Zebrafish Infection Model for Clostridioides difficile

Presented here is a safe and effective method to infect zebrafish larvae with fluorescently labeled anaerobic C. difficile by microinjection and noninvasive microgavage.

Entwicklung eines Larval Zebrafish Infection Model für Clostridioides difficile

Clostridioides difficile infection (CDI) is considered to be one of the most common healthcare-associated gastrointestinal infections in the United ...

Using Zebrafish Models of Human Influenza A Virus Infections to Screen Antiviral Drugs and Characterize Host Immune Cell Responses

Each year, seasonal influenza outbreaks profoundly affect societies worldwide. In spite of global efforts, influenza remains an intractable healthcare burden. The principle strategy to curtail infections is yearly vaccination. In individuals who have contracted influenza, antiviral drugs can mitigate symptoms. There is a clear and unmet need to develop alternative strategies to combat influenza. Several animal models have been created to model host-influenza interactions. Here, protocols for generating zebrafish models for systemic and localized human influenza A virus (IAV) infection are described. Using a systemic IAV infection model, small molecules with potential antiviral activity can be screened. As a proof-of-principle, a protocol that demonstrates the efficacy of the antiviral drug Zanamivir in IAV-infected zebrafish is described. It shows how disease phenotypes can be quantified to score the relative efficacy of potential antivirals in IAV-infected zebrafish. In recent years, there has been increased appreciation for the critical role neutrophils play in the human host response to influenza infection. The zebrafish has proven to be an indispensable model for the study of neutrophil biology, with direct impacts on human medicine. A protocol to generate a localized IAV infection in the Tg(mpx:mCherry) zebrafish line to study neutrophil biology in the context of a localized viral infection is described. Neutrophil recruitment to localized infection sites provides an additional quantifiable phenotype for assessing experimental manipulations that may have therapeutic applications. Both zebrafish protocols described faithfully recapitulate aspects of human IAV infection. The zebrafish model possesses numerous inherent advantages, including high fecundity, optical clarity, amenability to drug screening, and availability of transgenic lines, including those in which immune cells such as neutrophils are labeled with fluorescent proteins. The protocols detailed here exploit these advantages and have the potential to reveal critical insights into host-IAV interactions that may ultimately translate into the clinic.

Systemic and localized zebrafish infection models for human influenza A virus are demonstrated. Using a systemic infection model, zebrafish can be used to screen antiviral drugs. Using a localized infection model, zebrafish can be used to characterize host immune cell responses.

Mit Zebrabärbling Modelle menschlicher Influenza-A-Virus-Infektionen Virostatika auf Bildschirm und Host-Immun-Zell-Antworten Charakterisieren

Each year, seasonal influenza outbreaks profoundly affect societies worldwide. In spite of global efforts, influenza remains an intractable healthcare ...

Modeling Tuberculosis in Mycobacterium marinum Infected Adult Zebrafish

Mycobacterium tuberculosis is currently the deadliest human pathogen causing 1.7 million deaths and 10.4 million infections every year. Exposure to this bacterium causes a wide disease spectrum in humans ranging from a sterilized infection to an actively progressing deadly disease. The most common form is the latent tuberculosis, which is asymptomatic, but has the potential to reactivate into a fulminant disease. Adult zebrafish and its natural pathogen Mycobacterium marinum have recently proven to be an applicable model to study the wide disease spectrum of tuberculosis. Importantly, spontaneous latency and reactivation as well as adaptive immune responses in the context of mycobacterial infection can be studied in this model. In this article, we describe methods for the experimental infection of adult zebrafish, the collection of internal organs for the extraction of nucleic acids for the measurement of mycobacterial loads and host immune responses by quantitative PCR. The in-house-developed, M. marinum-specific qPCR assay is more sensitive than the traditional plating methods as it also detects DNA from non-dividing, dormant or recently dead mycobacteria. As both DNA and RNA are extracted from the same individual, it is possible to study the relationships between the diseased state, and the host and pathogen gene-expression. The adult zebrafish model for tuberculosis thus presents itself as a highly applicable, non-mammalian in vivo system to study host-pathogen interactions.

Modeling Tuberculosis in Mycobacterium marinum Infected Adult Zebrafish

Here, we present a protocol to model human tuberculosis in an adult zebrafish using its natural pathogen Mycobacterium marinum. Extracted DNA and RNA from the internal organs of infected zebrafish can be used to reveal the total mycobacterial loads in the fish and the host&#39;s immune responses with qPCR.

Modellierung von Tuberkulose Mycobacterium Marinum infizierten Erwachsenen Zebrafisch

Mycobacterium tuberculosis is currently the deadliest human pathogen causing 1.7 million deaths and 10.4 million infections every year. Exposure to this ...

Targeting Drugs to Larval Zebrafish Macrophages by Injecting Drug-Loaded Liposomes

Zebrafish (Danio rerio) larvae have developed into a popular model to investigate host-pathogen interactions and the contribution of innate immune cells to inflammatory disease due to their functionally conserved innate immune system. They are also widely used to examine how innate immune cells help guide developmental processes. By taking advantage of the optical transparency and genetic tractability of larval zebrafish, these studies often focus on live imaging approaches to functionally characterize fluorescently marked macrophages and neutrophils within intact animals. Due to their diverse functional heterogeneity and ever-expanding roles in disease pathogenesis, macrophages have received significant attention. In addition to genetic manipulations, chemical interventions are now routinely used to manipulate and examine macrophage behavior in larval zebrafish. Delivery of these drugs is typically limited to passive targeting of free drug through direct immersion or microinjection. These approaches rely on the assumption that any changes to macrophage behavior are the result of a direct effect of the drug on the macrophages themselves, and not a downstream consequence of a direct effect on another cell type. Here, we present our protocols for targeting drugs specifically to larval zebrafish macrophages by microinjecting drug-loaded fluorescent liposomes. We reveal that poloxamer 188-modified drug-loaded blue fluorescent liposomes are readily taken up by macrophages, and not by neutrophils. We also provide evidence that drugs delivered in this way can impact macrophage activity in a manner consistent with the mechanism of action of the drug. This technique will be of value to researchers wanting to ensure targeting of drugs to macrophages and when drugs are too toxic to be delivered by traditional methods like immersion.

Here, we describe the synthesis of drug-loaded liposomes and their microinjection into larval zebrafish for the purpose of targeting drug delivery to macrophage-lineage cells.

Targeting Drogen zu Larval Zebrafish Makrophagen durch Injektion von Drogen-geladenen Liposomen

Zebrafish (Danio rerio) larvae have developed into a popular model to investigate host-pathogen interactions and the contribution of innate immune cells ...

Infection of Zebrafish Larvae with Aspergillus Spores for Analysis of Host-Pathogen Interactions

Invasive aspergillosis (IA) is one of&#160;the most common fungal infections among immunocompromised individuals. Despite the availability of antifungal drugs, IA can cause &#62;50% mortality in infected immunocompromised patients. It is crucial to determine both host and pathogen factors that contribute to infection susceptibility and low survival rates in infected patients in order to develop novel therapeutics. Innate immune responses play a pivotal role in recognition and clearance of Aspergillus spores, though little is known about the exact cellular and molecular mechanisms. Reliable models are required to investigate detailed mechanistic interactions between the host and pathogen. The optical clarity and genetic tractability of zebrafish larvae make them an intriguing model&#160;to study host-pathogen interactions of multiple human bacterial and fungal infections in a live and intact host. This protocol describes a larval zebrafish Aspergillus infection model. First, Aspergillus spores are isolated and injected into the zebrafish hindbrain ventricle via microinjection. Then, chemical inhibitors such as immunosuppressive drugs are added directly to the larval water. Two methods to monitor the infection in injected larvae are described, including the 1) homogenization of larvae for colony forming unit (CFU) enumeration and 2) a repeated, daily live imaging setup. Overall, these techniques can be used to mechanistically analyze the progression of Aspergillus infection in vivo and can be applied to different host backgrounds and Aspergillus strains to interrogate host-pathogen interactions.

Infection of Zebrafish Larvae with Aspergillus Spores for Analysis of Host-Pathogen Interactions

This protocol describes an Aspergillus infection model in zebrafish larvae. Aspergillus spores are microinjected into the hindbrain of larvae, and chemical treatment is used to induce immunosuppression. Infection progression is monitored via a daily imaging setup to monitor fungal growth and immune responses as well as enumeration of live spores by colony forming unit plating.

Infektion von Zebrafischlarven mit Aspergillus Sporen zur Analyse von Wirts-Pathogen-Wechselwirkungen

Invasive aspergillosis (IA) is one of&#160;the most common fungal infections among immunocompromised individuals. Despite the availability of antifungal ...

Brain Ventricular Microinjections of Lipopolysaccharide into Larval Zebrafish to Assess Neuroinflammation and Neurotoxicity

Neuroinflammation is a key player in various neurological disorders, including neurodegenerative diseases. Therefore, it is of great interest to research and develop alternative in vivo neuroinflammation models to understand the role of neuroinflammation in neurodegeneration. In this study, a larval zebrafish model of neuroinflammation mediated by ventricular microinjection of lipopolysaccharide (LPS) to induce an immune response and neurotoxicity was developed and validated. The transgenic zebrafish lines elavl3:mCherry, ETvmat2:GFP, and mpo:EGFP were used for real-time quantification of brain neuron viability by fluorescence live imaging integrated with fluorescence intensity analysis. The locomotor behavior of zebrafish larvae was recorded automatically using a video-tracking recorder. The content of nitric oxide (NO), and the mRNA expression levels of inflammatory cytokines including interleukin-6 (IL-6), interleukin-1&#946; (IL-1&#946;), and human tumor necrosis factor &#945; (TNF-&#945;) were investigated to assess the LPS-induced immune response in the larval zebrafish head. At 24 h after the brain ventricular injection of LPS, loss of neurons and locomotion deficiency were observed in zebrafish larvae. In addition, LPS-induced neuroinflammation increased NO release and the mRNA expression of IL-6, IL-1&#946;, and TNF-&#945; in the head of 6 days post fertilization (dpf) zebrafish larvae, and resulted in the recruitment of neutrophils in the zebrafish brain. In this study, injection of zebrafish with LPS at a concentration of 2.5-5 mg/mL at 5 dpf was determined as the optimum condition for this pharmacological neuroinflammation assay. This protocol presents a new, quick, and efficient methodology for brain ventricle microinjection of LPS to induce LPS-mediated neuroinflammation and neurotoxicity in a zebrafish larva, which is useful for studying neuroinflammation and could also be used as a high-throughput in vivo drug screening assay.

This protocol demonstrates the microinjection of lipopolysaccharide into the brain ventricular region in a zebrafish larval model to study the resulting neuroinflammatory response and neurotoxicity.

Hirnventrikuläre Mikroinjektionen von Lipopolysaccharid in Zebrafischlarven zur Beurteilung von Neuroinflammation und Neurotoxizität

Neuroinflammation is a key player in various neurological disorders, including neurodegenerative diseases. Therefore, it is of great interest to research ...

Neurowissenschaften

A zWEDGI Technique to Visualize Fungal Pathogen-Infected Zebrafish Larvae

Source: Thrikawala, S. et al., <a href="https://appjove.unicartagenaproxy.elogim.com/v/61165">Infection of Zebrafish Larvae with Aspergillus Spores for Analysis of Host-Pathogen Interactions.</a>&#160;J. Vis. Exp.&#160;(2020)
The video demonstrates a zebrafish wounding and entrapment device technique for observing fluorescently labeled fungal pathogen infection in zebrafish larvae. Initial infection attracts macrophages, and as infection persists, neutrophil recruitment progresses at the injection site.

Eine zWEDGI-Technik zur Visualisierung von mit Pilzerregern infizierten Zebrafischlarven

1. Preparation of&#160;Aspergillus&#160;spores for injection

	From an&#160;Aspergillus&#160;spore suspension, calculate the volume needed to obtain 1 x ...