Wir möchten Dr. Vesper Fe Marie Ramos für die kritische Durchsicht des Manuskripts danken. Diese Arbeit wurde vom National Center for Research Resources (P20 RR0115635-6, C06 RR17417-01 und G20RR024001) und dem National Institute for Neurological Disorders and Stroke (2R01 NS052609) unterstützt.

Ein. Vorbereiten der Ausrüstung <ol><li> Verwenden Sie einen Misonix 3000 oder Misonix 4000 Ultraschallgerät (Farmingdale, NY) mit einem Thermo Electron Neslab EX-7 Wasserbad (Newington, NH), um eine konstante Temperatur von 37 ° C zu halten Beschallen die Proben in 200 ul dünnwandigen PCR-Röhrchen Streifen mit gewölbten Deckeln von Thermo Scientific (Waltham, MA) erhalten. </li><li> Ein neues Ultraschallgerät benötigt eine &quot;Pause&quot;-Periode des kontinuierlichen Betriebs 9. Eine zweimonatige Einfahrzeit besteht aus einem 40-sec Beschallung Burst und 10-minütigen Inkubation Zyklen mit der Amplitude eingestellt bis 10. Man sollte Erosion der gesamten Oberfläche des Titan Mikroplatte Horn (Abbildung 1, Teil B) zu beobachten. Das zirkulierende Wasser aussehen wird weiß-trüb durch Erosion des Titan Mikroplatten Horn. Ersetzen Sie diese Wasser täglich. </li><li> Die Verstärkung des PrP Sc wird während der Mikrotiterplatte Horn variieren. Die beste PrP Sc Amplifikationseffizienz kann innerhalb erhalten werdeneinem Radius von 5 cm von der Mitte der Mikrotiterplatte Horn (Siehe Abbildung 1, Panel C). </li><li> Eine Runde PMCA aus 144 Zyklen. Jeder Zyklus besteht aus 5 sec Beschallung und 10 min Inkubation. Dies wird in etwa 24 Stunden pro Runde PMCA ziehen. </li><li> Die Leistungsabgabe des Ultraschallbehandlung, auf die Beschallungsvorrichtung Bedienfeld angezeigt werden, variiert mit der Anzahl der PCR-Röhrchen Die in der Sonicator die Zahnstange und der Temperatur des zirkulierenden Wassers aus dem Wasserbad. Stellen Sie sicher, dass das Wasser äquilibriert bei 37 ° C und füllen nicht mehr als 30% der Sonicator die Röhrchenständer (Abbildung 1, Panel C). Verbreiten Sie die PCR-Röhrchen durch die Mikroplatten Horn. Mindestens eine Reihe von leeren Raum zwischen PCR-Röhrchen-Streifen und damit nicht mehr als vier Röhren zusammen pro Streifen verbunden (Abbildung 1, Panel C). </li><li> Die Stärke der Ultraschallbehandlung ist entscheidend für eine erfolgreiche Amplifikation Prionenstamm. Während Beschallen, die Amplitude, um eine Ausgangsleistung habenzwischen 155 ~ 170 Watt. In unserem Labor ist die Sendeleistung zu sechs und sieben für die Misonix 3000 und Misonix 4000 bzw. eingestellt. </li><li> Verwenden Sie destilliertes Wasser in das Wasserbad zu vermeiden akkumulieren harten Wasserflecken. Ersetzen Sie diese Wasser wöchentlich. Während der Inkubation und Beschallung Zyklen wird Kondenswasser im Inneren des Mikroplatten-horn Deckel auftreten. Zur Vermeidung von Kondensation, bringen ein kleines Aquarium Heizkissen an die Spitze des Sonicator Gehege, wie in Abbildung 1, Panel A gezeigt </li></ol> 2. Vorbereitung der Proben <ol><li> Alle Verfahren, die Tiere wurden von der Creighton University Institutional Animal Care genehmigt und Verwenden Ausschusses und entsprechen dem Leitfaden für die Pflege und Verwendung von Labortieren. Vor jedem Gewebe Sammlung, das Tier narkotisiert und muss transkardial perfundiert mit eiskaltem Phosphat gepufferte Kochsalzlösung mit 5 mM EDTA bei pH 7,4, um Blut aus dem Gehirn zu entfernen und verhindern die Inhibierung derPMCA Reaktion durch Blut 7. Sammle tierischen Geweben rasch unter aseptischen Bedingungen und haben engagierte Dissektion Tools für jede Prionenstamm. Nach Dissektion, legen Sie das Gewebe in einem 1,5 ml Mikrozentrifugenröhrchen, frieren Flash auf Trockeneis, und speichern Sie sie bei -80 ° C bis zur Homogenisierung. </li><li> Um die PMCA Substrat (PrP C) herzustellen, homogenisieren eine nicht infizierte Hamsterhirn (UN BH) zu einer 10% Gewicht / Volumen (w / v) Lösung mit eiskaltem Kovertierungspuffers (siehe Teil 3) mit einem Tenbroeck Gewebe Mahlwerk. Während Homogenisieren, darauf achten, nicht die Luft im Inneren der Mühle zu erhalten zu vermeiden übermäßige Schaumbildung der Lösung. Klären der Lösung durch Zentrifugieren bei 500 xg für 30 sec und Aliquot des Überstandes in 1,5 ml Mikrozentrifugenröhrchen. Lagerung bei -80 ° C bis zur weiteren Verwendung. </li><li> Um die PMCA Saatgut (PrP Sc)-Lösung herzustellen, ein infektiöses Material homogenisieren (Gehirn, Milz, Lymphknoten, Geweben oder anderen kontaminierten Bodens) zu einer 10% w / v Lösung mit eiskaltem water und aliquoten die Lösung in 0,6 ml Mikrozentrifugenröhrchen. Lagerung bei -80 ° C bis zur weiteren Verwendung. </li></ol> 3. Vorbereiten Conversion Buffer <ol><li> Wiegen 0,5093 g Triton X-100 in einem 50 ml Messkolben (Ergebnis ist eine 1% Endkonzentration an Triton X-100) (Sigma-Aldrich GmbH, Steinheim, Deutschland). </li><li> Fügen Sie eine komplette Protease Inhibitor Tablette (Roche Diagnostics GmbH, Mannheim, Deutschland). </li><li> Hinzufügen 0,0931 g EDTA (diese wird in einem 5 mM Endkonzentration von EDTA führen) (Mallinckrodt Baker Inc.; Phillipsburg, NJ). </li><li> Den pH-Wert auf 7,4 mit 1 N NaOH. </li><li> Lautstärke auf 50 ml mit Dulbeccos phosphatgepufferte Kochsalzlösung (DPBS) (Mediatech Inc.; Manassas, VA). </li><li> Filtern der Lösung durch einen 0,45 um Nitrocellulosemembran mit einer Vakuumfiltervorrichtung. Die Umwandlung Puffer bei 4 ° C für nicht mehr als einen Monat gelagert werden. </li></ol> 4. Verstärkung des Prion-Stämme mit PMCA <ol><li>Verdünnt das PMCA Saatgut in den PMCA Substrat in einem Verhältnis von 1:20 (dh Mischung 5 ul der PMCA Saatgut und 95 ul der PMCA Substrat) in einer PCR-Röhrchen. Entfernen und speichern 15 ul Aliquots bei -80 ° C für unsonicated Kontrolle; dies unsonicated Steuerung wird verwendet, um die PrP Sc Verstärkung durch Proteinase K (PK) Verdauung durch Western Blot (WB) Analyse folgt quantifizieren. Eine zusätzliche Kontrolle unsonicated könnte durch Platzieren eines zweiten 15 ul Aliquots bei 37 ° C für die Dauer der PMCA Reaktion erzeugt werden. Ein Minimum von drei Wiederholungen wird für statistische Zwecke benötigten. </li><li> Gegenstand der Rest der Probe (70 ul) mit einer Runde der PMCA wie auf Abbildung 1 dargestellt, Panel A Schütteln Röhrchen alle 5 Stunden, um eine Wasserkondensation auf dem gewölbten Deckel des PCR-Röhrchen zu vermeiden. </li><li> Die Probe Rohren sollten ausgegliedert werden und sanft gevortext (dabei darauf achten, dass die Lösung nicht in den gewölbter Deckel gehen) vor dem Öffnen nach jedem Verfahren, um sicherzustellen, homogeneity und vermeiden mögliche Kontamination. </li><li> Für die serielle PMCA (sPMCA) der kurzen Inkubationszeit Stämme (dh HY TME, HaCWD oder 263K), wird der beschallten Material bei einem Verhältnis von 1:20, indem 5 ul der beschallten Probe von Runde eins in 95 ml frisches infizierten Hirnhomogenat (Abbildung 2, Panel B). </li><li> Für sPMCA der langen Inkubationszeit Stämmen (dh DY TME, 139h, 22CH, 22Ah oder ME7H), verdünnt das beschallten Materials in einem Verhältnis von 1:1 durch Transferieren 50 ul der beschallten Probe aus der ersten Runde in 50 ml frisches nichtinfizierten Hirnhomogenat (Abbildung 2, Panel B). </li><li> Entfernen Sie die zwei 15 ul Aliquots aus dem zuvor verdünnt beschallten Gemisch (aus den Schritten 4,4 bzw. 4,5) und speichern einer von ihnen bei -80 ° C und die andere bei 37 ° C (unsonicated Control-Lösungen für PMCA Runde zwei). Unterziehen die Überreste einer PMCA Runde zwei. </li><li> Dieser Vorgang kann beliebig oft wiederholt werden. In unserem Labor haben wirbis zu fünfzehn PMCA Runden durchgeführt haben, mit den Dehnungs-Eigenschaften bleiben unverändert. </li><li> PK verdauen die Proben. Für eine typische WB mischen 5 ul PK 80 ug / ml bis 5 ul Probe (diese Lösung wird eine endgültige PK Konzentration von 40 ug / ml haben) und bei 37 ° C für eine Stunde. Fügen Sie 10 ul Gelladepuffer. Kochen Sie diese Lösung für 10 min. Lassen Sie die Lösung abkühlen und laden 10 ul in das Gel. </li><li> Um den Erfolg der Amplifikation zu berechnen führen eine Analyse an den WB PK-verdauten Proben, um die Menge der verstärkten PrP Sc durch Vergleich, um entweder zu schätzen, die unsonicated Steuerelementen 20,21 Abbildung 2, Tafel C oder bekannte Mengen von PK-unverdaute rekombinante PrP. </li></ol> 5. Vermeiden Kreuzkontamination Critical müssen Maßnahmen ergriffen werden, um Kreuzkontaminationen und das Auftreten von Fehlalarmen durch de novo Bildung von Protease beständige Produkte zu minimieren. </p&gt; <ol><li> Verwenden Sie einen dedizierten Satz Dissektion Tools (zB Zangen, Pinzetten, Scheren) für die Probenentnahme für jeden Prionenstamm. </li><li> Vor Homogenisieren infizierten Gehirnen als PMCA Substrat verwendet werden, wischen Sie die Pipetten mit 1% Bleichmittel. Weichen Sie das Ultraschallgerät die PCR-Röhrchen Rack, Gewebe Homogenisatoren und PCR-Röhrchen Lagerregale mit 1% Bleichmittel für 10 min und anschließend gründlich mit destilliertem Wasser. </li><li> Decken Sie die Arbeitsfläche mit einem frischen Versi-Dry Lab Soaker jedes Mal eine neue Probe homogenisiert werden, ist eine neue PMCA Experiment vorbereitet zu sein, oder wenn Aliquotierung zwischen sPMCA Runden. </li><li> Verwenden Sie neue Handschuhe jedes Mal neue Proben behandelt (vor allem beim Übertragen Aliquots zwischen sPMCA Runden) werden. </li><li> Verwenden Sie kurze Beschallung Bursts für jeden PMCA Zyklus. Cycles of 5 sec Beschallung mit 10 min Inkubation kombiniert ist ausreichend, um Prionen ohne dass de novo PrP Sc 1,20,21,23,24 verstärken. Wie andere Labors haben gezeigt, Erhöhung derBeschallungszeit, die Erhöhung der Beschallung Amplitude und Erweiterung der Anzahl der PMCA-Zyklen erhöht die Wahrscheinlichkeit für die de novo PrP Sc Bildung 2. </li></ol>

<ol>
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Herausforderungen der Verstärkung infektiöse Prion-Proteine ​​sind die langen Inkubationszeit und die Kosten der In-vivo-Experimente. Die PMCA Technik ist ein kostengünstiges Mittel, um infektiöse Prion-Agenten zu verstärken. Mehreren Laboratorien haben die Fähigkeit, genau zu amplifizieren PMCA Prionenstämme in vitro 7, 9, 12, 14, 19,24 bestätigt. Prion-Erkrankungen können zwischen verschiedenen Arten übertragen werden. Bessen und Marsh haben effek...

<table border="1"><tbody><tr><td> Reagenz / Equipment </td><td> Hersteller </td><td> Cat. Anzahl </td></tr><tr><td> Misonix 3000 </td><td> Misonix </td><td> S-3000 </td></tr><tr><td> Misonix 4000 </td><td> Misonix </td><td> S-4000 </td></tr><tr><td> Tenbroeck Tissue Grinder </td><td> Kontes </td><td> 885000-0007 </td></tr><tr><td> Neslab EX-7 Wasserbad </td><td> Thermo Electron </td><td> Neslab EX-7 </td></tr><tr><td> 0,2 ml PCR Tube Strips </td><td> Thermo Scientific </td><td> AB-0451 </td></tr><tr><td> Triton X-100 </td><td> Sigma Aldrich </td><td> T9284-100ML </td></tr><tr><td> Komplette Protease Inhibitor </td><td> Roche </td><td> 11 697 498 001 </td></tr><tr><td> EDTA </td><td> JT Baker </td><td> 4040-00 </td></tr><tr><td> DPBS </td><td> Mallinckrodt Baker Mediatech </td><td> 21-031-CV </td></tr><tr><td> Versi-Dry Lab Soakers </td><td> Fisher Scientific </td><td> 14 206 28 </td></tr><tr><td> Repti Therm Heater </td><td> Zoo Med Laboratories, Inc. </td><td> RH-4 </td></tr></tbody></table>

protein misfolding cyclic amplification of prions

Prionen sind infektiöse Agenzien, die unweigerlich tödlichen übertragbaren spongiformen Enzephalopathie (TSE) verursachen bei Menschen und Tieren 9,18. Das Prionprotein hat zwei verschiedene Isoformen, die nicht-infektiösen Host-codierte Protein (PrP C) und das infektiöse Protein (PrP Sc), eine abnormal gefaltete Isoform von PrP C 8. Eine der Herausforderungen bei der Arbeit mit Prion-Agenten ist die lange Inkubationszeit vor der Entwicklung von klinischen Anzeichen nach Host Inokulation 13. Das traditionell langen und teuren Tier-Bioassay Studien beauftragt. Darüber hinaus werden die biochemischen und biophysikalischen Eigenschaften von PrP Sc schlecht charakterisiert durch ihre ungewöhnliche Konformation und Aggregation Staaten. PrP Sc kann Saatgut die Umwandlung von PrP C zu PrP Sc in vitro 14. PMCA ist ein in vitro-Technik, nimmt advantage dieser Fähigkeit mit Ultraschallbehandlung und Inkubation Zyklen, große Mengen an PrP Sc zu erzeugen, mit einer beschleunigten Rate von einer Anlage mit überschüssigen Mengen an PrP C und winzige Mengen des PrP Sc Saatgut 19. Diese Technik hat sich als wirksam rekapitulieren die Art und Stamm von PrP Sc Spezifität Umwandlung von PrP C zu Prionenstamm Interferenz emulieren, und mit sehr geringen Mengen von PrP Sc aus infizierten Geweben, Fluiden, und Umweltproben 6,7,16 amplifizieren, 23. Dieses Papier Details der PMCA Protokoll, einschließlich Empfehlungen zur Minimierung Kontamination Erzeugung konsistente Ergebnisse und Quantifizierung dieser Ergebnisse. Wir diskutieren auch mehrere PMCA Anwendungen, einschließlich der Erzeugung und Charakterisierung von Prion-Stämme, Prionenstamm Störungen, und der Nachweis von Prionen in der Umwelt.

Proteinfehlfaltung zyklischen Amplifikation (PMCA) wird verwendet, um PrP Sc in vitro 7, 12, 14, 19, 24 zu amplifizieren. Eine erfolgreiche Amplifikation PrP Sc ist durch einen Anstieg der Bandenintensität auf Western Blots des PK-Prionprotein (Migration zwischen 19 und 30 kDa für Hamster abstammenden Prionenstämme), wie in 3 gezeigt ist. Die Zunahme seiner Bandenintensität nach PMCA zeigt Verstärkung des PK-resistente PrP Sc Mat...

Watch this Scientific Journal Video about Protein Misfolding Cyclic Amplification of Prions at JoVE.com

Protein Misfolding Cyclic Amplification of Prions

Proteinfehlfaltung zyklischen Amplifikation (PMCA) ist ein in vitro-Assay zur Untersuchung von Prionen Umwandlung und Dehnung und Artgrenzen. Es kann auch als ein Prion-Nachweis-Assay verwendet werden.

Proteinfehlfaltungen Cyclic Amplification von Prionen

Prions  are infectious agents that cause the inevitably fatal transmissible spongiform  encephalopathy (TSE) in animals and humans9,18. The prion protein ...

protein-misfolding-cyclic-amplification-of-prions

Research

JoVE Journal

Immunology and Infection

19.4K Aufrufe.  University of Nebraska at Lincoln. Proteinfehlfaltung zyklischen Amplifikation (PMCA) ist ein in vitro-Assay zur Untersuchung von Prionen Umwandlung und Dehnung und Artgrenzen. Es kann auch als ein Prion-Nachweis-Assay verwendet werden.

Serie: Protein Misfolding Cyclic Amplification of Prions

Procedures for Identifying Infectious Prions After Passage Through the Digestive System of an Avian Species

Infectious prion (PrPRes) material is likely the cause of fatal, neurodegenerative transmissible spongiform encephalopathy (TSE) diseases1. Transmission of TSE diseases, such as chronic wasting disease (CWD), is presumed to be from animal to animal2,3 as well as from environmental sources4-6. Scavengers and carnivores have potential to translocate PrPRes material through consumption and excretion of CWD-contaminated carrion. Recent work has documented passage of PrPRes material through the digestive system of American crows (Corvus brachyrhynchos), a common North American scavenger7.
We describe procedures used to document passage of PrPRes material through American crows. Crows were gavaged with RML-strain mouse-adapted scrapie and their feces were collected 4 hr post gavage. Crow feces were then pooled and injected intraperitoneally into C57BL/6 mice. Mice were monitored daily until they expressed clinical signs of mouse scrapie and were thereafter euthanized. Asymptomatic mice were monitored until 365 days post inoculation. Western blot analysis was conducted to confirm disease status. Results revealed that prions remain infectious after traveling through the digestive system of crows and are present in the feces, causing disease in test mice.

Scavengers have potential to translocate infectious transmissible spongiform encephalopathy prions in their feces to disease-free areas. We detail methods used to determine if mouse-adapted scrapie prions remain infectious after passage though the digestive tract of American crows (Corvus brachyrhynchos), a common consumer of dead animals.

Verfahren zur Identifizierung von Infektions Prionen Nach Passage durch das Verdauungssystem von eine Vogelart

Infectious prion (PrPRes) material is likely the cause of fatal, neurodegenerative transmissible spongiform encephalopathy (TSE) diseases1. Transmission ...

Forschung

Immunologie und Infektion

Demonstrating a Multi-drug Resistant Mycobacterium tuberculosis Amplification Microarray

Simplifying microarray workflow is a necessary first step for creating MDR-TB microarray-based diagnostics that can be routinely used in lower-resource environments. An amplification microarray combines asymmetric PCR amplification, target size selection, target labeling, and microarray hybridization within a single solution and into a single microfluidic chamber. A batch processing method is demonstrated with a 9-plex asymmetric master mix and low-density gel element microarray for genotyping multi-drug resistant Mycobacterium tuberculosis (MDR-TB). The protocol described here can be completed in 6 hr and provide correct genotyping with at least 1,000 cell equivalents of genomic DNA. Incorporating on-chip wash steps is feasible, which will result in an entirely closed amplicon method and system. The extent of multiplexing with an amplification microarray is ultimately constrained by the number of primer pairs that can be combined into a single master mix and still achieve desired sensitivity and specificity performance metrics, rather than the number of probes that are immobilized on the array. Likewise, the total analysis time can be shortened or lengthened depending on the specific intended use, research question, and desired limits of detection. Nevertheless, the general approach significantly streamlines microarray workflow for the end user by reducing the number of manually intensive and time-consuming processing steps, and provides a simplified biochemical and microfluidic path for translating microarray-based diagnostics into routine clinical practice.

Demonstrating a Multi-drug Resistant Mycobacterium tuberculosis Amplification Microarray

An amplification microarray combines asymmetric PCR amplification and microarray hybridization into a single chamber, which significantly streamlines microarray workflow for the end user. Simplifying microarray workflow is a necessary first step for creating microarray-based diagnostics that can be routinely used in lower-resource environments.

Der Nachweis eines multiresistenten<em&gt; Mycobacterium tuberculosis</em&gt; Verstärkung Microarray

Simplifying microarray workflow is a necessary first step for creating MDR-TB microarray-based diagnostics that can be routinely used in lower-resource ...

Loop-mediated Isothermal Amplification (LAMP) Assays for the Species-specific Detection of Eimeria that Infect Chickens

Eimeria species parasites, protozoa which cause the enteric disease coccidiosis, pose a serious threat to the production and welfare of chickens. In the absence of effective control clinical coccidiosis can be devastating. Resistance to the chemoprophylactics frequently used to control Eimeria is common and sub-clinical infection is widespread, influencing feed conversion ratios and susceptibility to other pathogens such as Clostridium perfringens. Despite the availability of polymerase chain reaction (PCR)-based tools, diagnosis of Eimeria infection still relies almost entirely on traditional approaches such as lesion scoring and oocyst morphology, but neither is straightforward. Limitations of the existing molecular tools include the requirement for specialist equipment and difficulties accessing DNA as template. In response a simple field DNA preparation protocol and a panel of species-specific loop-mediated isothermal amplification (LAMP) assays have been developed for the seven Eimeria recognised to infect the chicken. We now provide a detailed protocol describing the preparation of genomic DNA from intestinal tissue collected post-mortem, followed by setup and readout of the LAMP assays. Eimeria species-specific LAMP can be used to monitor parasite occurrence, assessing the efficacy of a farm&#8217;s anticoccidial strategy, and to diagnose sub-clinical infection or clinical disease with particular value when expert surveillance is unavailable.

Loop-mediated Isothermal Amplification LAMP Assays for the Species-specific Detection of Eimeria that Infect Chickens

Diagnosis of Eimeria infection in chickens remains demanding. Parasite morphology- and host pathology-led approaches are commonly inconclusive, while molecular approaches based on PCR have proven demanding in cost and expertise. The aim of this protocol is to establish loop-mediated isothermal amplification (LAMP) as a straightforward molecular diagnostic for eimerian infection.

Loop-vermittelte isothermen Amplifikation (LAMP) Assays für die artspezifischen Nachweis von<em&gt; Eimeria</em&gt;, Die Hühner infizieren

Eimeria species parasites, protozoa which cause the enteric disease coccidiosis, pose a serious threat to the production and welfare of chickens. In the ...

The Development of Lyophilized Loop-mediated Isothermal Amplification Reagents for the Detection of Coxiella burnetii

Coxiella burnetii, the agent causing Q fever, is an obligate intracellular bacterium. PCR based diagnostic assays have been developed for detecting C. burnetii DNA in cell cultures and clinical samples. PCR requires specialized equipment and extensive end user training, and therefore, it is not suitable for routine work especially in a resource-constrained area. We have developed a loop-mediated isothermal amplification (LAMP) assay to detect the presence of C. burnetii in patient samples. This method is performed at a single temperature around 60 &#176;C in a water bath or heating block. The sensitivity of this LAMP assay is very similar to PCR with a detection limit of about 25 copies per reaction. This report describes the preparation of the reaction using lyophilized reagents and visualization of results using hydroxynaphthol blue (HNB) or a UV lamp with fluorescent intercalating dye in the reaction. The LAMP reagents were lyophilized and stored at room temperature (RT) for one month without loss of detection sensitivity. This LAMP assay is particularly robust because the reaction mixture preparation does not involve complex steps. This method is ideal for use in resource-limited settings where Q fever is endemic.

The Development of Lyophilized Loop-mediated Isothermal Amplification Reagents for the Detection of Coxiella burnetii

We described here a simple loop-mediated isothermal amplification (LAMP) method using lyophilized reagents for the detection of C. burnetii in patient samples.

Die Entwicklung der Lyophilisierte Loop-mediated Isothermal Amplification Reagenzien zum Nachweis von<em&gt; Coxiella burnetii</em

Coxiella burnetii, the agent causing Q fever, is an obligate intracellular bacterium. PCR based diagnostic assays have been developed for detecting C. ...

Real-time Quaking-induced Conversion Assay for Detection of CWD Prions in Fecal Material

The RT-QuIC technique is a sensitive in vitro cell-free prion amplification assay based mainly on the seeded misfolding and aggregation of recombinant prion protein (PrP) substrate using prion seeds as a template for the conversion. RT-QuIC is a novel high-throughput technique which is analogous to real-time polymerase chain reaction (PCR). Detection of amyloid fibril growth is based on the dye Thioflavin T, which fluoresces upon specific interaction with &#7526;-sheet rich proteins. Thus, amyloid formation can be detected in real time. We attempted to develop a reliable non-invasive screening test to detect chronic wasting disease (CWD) prions in fecal extract. Here, we have specifically adapted the RT-QuIC technique to reveal PrPSc seeding activity in feces of CWD infected cervids. Initially, the seeding activity of the fecal extracts we prepared was relatively low in RT-QuIC, possibly due to potential assay inhibitors in the fecal material. To improve seeding activity of feces extracts and remove potential assay inhibitors, we homogenized the fecal samples in a buffer containing detergents and protease inhibitors. We also submitted the samples to different methodologies to concentrate PrPSc on the basis of protein precipitation using sodium phosphotungstic acid, and centrifugal force. Finally, the feces extracts were tested by optimized RT-QuIC which included substrate replacement in the protocol to improve the sensitivity of detection. Thus, we established a protocol for sensitive detection of CWD prion seeding activity in feces of pre-clinical and clinical cervids by RT-QuIC, which can be a practical tool for non-invasive CWD diagnosis.

Here, we present a protocol to describe a simple, fast and efficient prion amplification technique, the real-time quaking-induced conversion (RT-QuIC) method.

Echtzeit-Beben-induzierte Umwandlung Test zur Erkennung von CWD Prionen in Fäkalien

The RT-QuIC technique is a sensitive in vitro cell-free prion amplification assay based mainly on the seeded misfolding and aggregation of recombinant ...

Building Up a High-throughput Screening Platform to Assess the Heterogeneity of HER2 Gene Amplification in Breast Cancers

Targeted therapies against the human epidermal growth factor receptor 2 (HER2) have radically changed the outcome of patients with HER2-positive breast cancers. However, a minority of cases displays a heterogeneous distribution of HER2-positive cells, which generates major clinical challenges. To date, no reliable and standardized protocols for the characterization and quantification of HER2 heterogeneous gene amplification in large cohorts have been proposed. Here, we present a high-throughput methodology to simultaneously assess the HER2 status across different topographic areas of multiple breast cancers. In particular, we illustrate the laboratory procedure to construct enhanced tissue microarrays (TMAs) incorporating a targeted mapping of the tumors. All TMA parameters have been specifically optimized for the silver in situ hybridization (SISH) of formalin-fixed paraffin-embedded (FFPE) breast tissues. Immunohistochemical analysis of the prognostic and predictive biomarkers (i.e., ER, PR, Ki67, and HER2) should be performed using automated procedures. A customized SISH protocol has been implemented to allow a high-quality molecular analysis across multiple tissues that underwent different fixation, processing, and storage procedures. In this study, we provide a proof-of-principle that specific DNA sequences could be localized simultaneously in distinct topographic areas of multiple and heterogeneously processed breast cancers using an efficient and cost-effective method.

Heterogeneous distribution of HER2-positive cells can be observed in a subset of breast cancers and generates clinical dilemmas. Here, we introduce a reliable and cost-effective protocol to define, quantify, and compare HER2 intra-tumor genetic heterogeneity in a large series of heterogeneously processed breast cancers.

Aufbau einer Hochdurchsatz-Screening-Plattform zu beurteilen, die Heterogenität der HER2-Gene-Verstärkung in Brust-

Targeted therapies against the human epidermal growth factor receptor 2 (HER2) have radically changed the outcome of patients with HER2-positive breast ...

Dissecting Multi-protein Signaling Complexes by Bimolecular Complementation Affinity Purification (BiCAP)

The assembly of protein complexes is a central mechanism underlying the regulation of many cell signaling pathways. A major focus of biomedical research is deciphering how these dynamic protein complexes act to integrate signals from multiple sources in order to direct a specific biological response, and how this becomes deregulated in many disease settings. Despite the importance of this key biochemical mechanism, there is a lack of experimental techniques that can facilitate the specific and sensitive deconvolution of these multi-molecular signaling complexes.
Here this shortcoming is addressed through the combination of a protein complementation assay with a conformation-specific nanobody, which we have termed Bimolecular Complementation Affinity Purification (BiCAP). This novel technique facilitates the specific isolation and downstream proteomic characterization of any pair of interacting proteins, to the exclusion of un-complexed individual proteins and complexes formed with competing binding partners. 
The BiCAP technique is adaptable to a wide array of downstream experimental assays, and the high degree of specificity afforded by this technique allows more nuanced investigations into the mechanics of protein complex assembly than is currently possible using standard affinity purification techniques.

Dissecting Multi-protein Signaling Complexes by Bimolecular Complementation Affinity Purification BiCAP

This manuscript describes the protocol for Bimolecular Complementation Affinity Purification (BiCAP). This novel method facilitates the specific isolation and downstream proteomic characterization of any two interacting proteins, while excluding un-complexed individual proteins as well as complexes formed with competing binding partners.

Sezieren Signalisierung Multi-Protein-komplexe durch eine Bimolekulare Ergänzung Affinitätsreinigung (BiCAP)

The assembly of protein complexes is a central mechanism underlying the regulation of many cell signaling pathways. A major focus of biomedical research ...

Automated Behavioral Analysis of Large C. elegans Populations Using a Wide Field-of-view Tracking Platform

Caenorhabditis elegans is a well-established animal model in biomedical research, widely employed in functional genomics and ageing studies. To assess the health and fitness of the animals under study, one typically relies on motility readouts, such as the measurement of the number of body bends or the speed of movement. These measurements usually involve manual counting, making it challenging to obtain good statistical significance, as time and labor constraints often limit the number of animals in each experiment to 25 or less. Since high statistical power is necessary to obtain reproducible results and limit false positive and negative results when weak phenotypic effects are investigated, efforts have recently been made to develop automated protocols focused on increasing the sensitivity of motility detection and multi-parametric behavioral profiling. In order to extend the limit of detection to the level needed to capture the small phenotypic changes that are often crucial in genetic studies and drug discovery, we describe here a technological development that enables the study of up to 5,000 individual animals simultaneously, increasing the statistical power of the measurements by about 1,000-fold compared to manual assays and about 100-fold compared to other available automated methods.

Automated Behavioral Analysis of Large C. elegans Populations Using a Wide Field-of-view Tracking Platform

We describe protocols for using the wide field-of-view nematode tracking platform (WF-NTP), which enables high-throughput phenotypic characterization of large populations of Caenorhabditis elegans. These protocols can be used to characterize subtle behavioral changes in mutant strains or in response to pharmacological treatment in a highly scalable fashion.

Automatisierte verhaltensbasierte Analyse der großen C. Elegans Populationen verwenden ein breites Sichtfeld Tracking-Plattform

Caenorhabditis elegans is a well-established animal model in biomedical research, widely employed in functional genomics and ageing studies. To assess the ...

Generation, Amplification, and Titration of Recombinant Respiratory Syncytial Viruses

The use of recombinant viruses has become crucial in basic or applied virology. Reverse genetics has been proven to be an extremely powerful technology, both to decipher viral replication mechanisms and to study antivirals or provide development platform for vaccines. The construction and manipulation of a reverse genetic system for a negative-strand RNA virus such as a respiratory syncytial virus (RSV), however, remains delicate and requires special know-how. The RSV genome is a single-strand, negative-sense RNA of about 15 kb that serves as a template for both viral RNA replication and transcription. Our reverse genetics system uses a cDNA copy of the human RSV long strain genome (HRSV). This cDNA, as well as cDNAs encoding viral proteins of the polymerase complex (L, P, N, and M2-1), are placed in individual expression vectors under T7 polymerase control sequences. The transfection of these elements in BSR-T7/5 cells, which stably express T7 polymerase, allows the cytoplasmic replication and transcription of the recombinant RSV, giving rise to genetically modified virions. A new RSV, which is present at the cell surface and in the culture supernatant of BSRT7/5, is gathered to infect human HEp-2 cells for viral amplification. Two or three rounds of amplification are needed to obtain viral stocks containing 1 x 106 to 1 x 107 plaque-forming units (PFU)/mL. Methods for the optimal harvesting, freezing, and titration of viral stocks are described here in detail. We illustrate the protocol presented here by creating two recombinant viruses respectively expressing free green fluorescent protein (GFP) (RSV-GFP) or viral M2-1 fused to GFP (RSV-M2-1-GFP). We show how to use RSV-GFP to quantify RSV replication and the RSV-M2-1-GFP to visualize viral structures, as well as viral protein dynamics in live cells, by using video microscopy techniques.

We describe a method for generating and amplifying genetically modified respiratory syncytial viruses (RSVs) and an optimized plaque assay for RSVs. We illustrate this protocol by creating two recombinant viruses that respectively allow quantification of RSV replication and live analysis of RSV inclusion bodies and inclusion bodies-associated granules dynamics.

Erzeugung, Verstärkung und Titration von rekombinanten Respiratory Syncytial Viren

The use of recombinant viruses has become crucial in basic or applied virology. Reverse genetics has been proven to be an extremely powerful technology, ...

Reverse Transcription Loop-Mediated Isothermal Amplification (RT-LAMP) Assay for the Specific and Rapid Detection of Tilapia Lake Virus

Tilapia lake virus disease (TiLVD), an emerging viral disease in tilapia caused by the tilapia lake virus (TiLV), is a persistent challenge in the aquaculture industry that has resulted in the mass morbidity and mortality of tilapia in many parts of the world. An effective, rapid, and accurate diagnostic assay for TiLV infection is therefore necessary to detect the initial infection and to prevent the spread of the disease in aquaculture farming. In this study, a highly sensitive and practical reverse transcription loop-mediated isothermal amplification (RT-LAMP) method is presented to detect tilapia lake virus in fish tissue. A comparison of the RT-qPCR and RT-LAMP assays of infected samples revealed positive results in 63 (100%) and 51 (80.95%) samples, respectively. Moreover, an analysis of uninfected samples showed that all 63 uninfected tissues yielded negative results for both the RT-qPCR and RT-LAMP assays. The cross-reactivity with five pathogens in tilapia was evaluated using RT-LAMP, and all the tests showed negative results. Both the liver and mucus samples obtained from infected fish showed comparable results using the RT-LAMP method, suggesting that mucus can be used in RT-LAMP as a nonlethal assay to avoid killing fish. In conclusion, the results demonstrated that the presented RT-LAMP assay provides an effective method for TiLV detection in tilapia tissue within 1 h. The method is therefore recommended as a screening tool on farms for the rapid diagnosis of TiLV.

Reverse Transcription Loop-Mediated Isothermal Amplification RT-LAMP Assay for the Specific and Rapid Detection of Tilapia Lake Virus

We present an RT-LAMP assay for the detection of TiLV in tilapia fish using simple instruments over a relatively short period of time compared to conventional RT-PCR techniques. This protocol may help control the epidemic spread of TiLVD, especially in developing countries.