Diese Forschung wurde von Naval Medical Research Center, Forschung Arbeitseinheit 6000.RAD1.J.A0310 unterstützt. Die in diesem Artikel sind die der Autoren und geben nicht unbedingt die offizielle Politik oder Position des Department of the Navy, Department of Defense, oder der US-Regierung widerspiegeln. Wei-Mei Ching ist ein Mitarbeiter der US-Regierung. Diese Arbeit wurde im Rahmen ihrer offiziellen Aufgaben vorbereitet. Titel 17 USC § 105 heißt es: &quot;Der Urheberrechtsschutz unter diesem Titel für jede Arbeit der Regierung der Vereinigten Staaten nicht zur Verfügung steht.&quot; Titel 17 USC §101 definiert eine US-Regierung Arbeit als Arbeit, die durch Militärdienst Mitglied oder Mitarbeiter der US-Regierung als Teil der Person durch Amtspflichten.

1. Bereiten Sie Plasmid-DNA Verdünnungen als Standard für den LAMP-Reaktion <ol><li> Verwenden eines Spektrophotometers die optische Dichte (OD) bei 260 nm zu messen , um das Plasmid (enthaltend Zielgen IS1111a von C. burnetii RSA 493) DNA - Konzentration zu bestimmen. Eine OD 260 von 1 entspricht 50 ug / ul DNA. </li><li> Konvertieren Sie die Menge von Plasmid-DNA in die Kopienzahl. Da die Größe des Plasmids 6330 bp ist, ist das Molekulargewicht dieses Plasmids 4,1 x 10 6 g (6.330 bp x 649 g / bp). Die DNA-Konzentration des Plasmids ist 34,2 ng / &amp; mgr; l (wie in Schritt bestimmt 1.1). 1 &amp; mgr; l dieser DNA - Probe enthält 34,2 ng Plasmid - DNA, zu gleich 5 x 10 9 Kopien (34,2 x 10 -9 g / 4,1 x 10 6 6,02 x 10 gx 23) von DNA. </li><li> Zugabe von 10 &amp; mgr; l Plasmid - DNA (5 x 10 9 Kopien / ul) und 90 ul Wasser für eine 10-fache Verdünnung einer DNA - Probe von 5 x 10 8 Kopien zu erstellen / ul. </li><li> Wiederholen Sie Schritt 1.3 zur Herstellung von DNA - Proben von 5 x 10 7, 5 x 10 6, 5 x 10 5, 5 x 10 4, 5 × 10 3, 5 x 10 2, 5 x 10 1 und 5 x 10 0 Kopien / ul. </li></ol> 2. Bereiten Sie DNA-Vorlage von Proben für die LAMP-Reaktion <ol><li> Führen DNA Extraktion aus Humanplasmaproben Kommerzielle DNA Mini Kit nach Herstellerprotokoll. Verwenden Sie eine Gesamtmenge von 200 ul Probe für die Extraktion und Elution extrahierten DNA in einem 20 &amp; mgr; l Volumen. </li></ol> 3. Bereiten Sie 2x LAMP-Reaktionspuffer <ol><li> Mischen Sie 200 ul 10x Pol Buffer, 320 ul 5 M Trimethylglycin, 12 ul 1 M MgSO 4, 280 &amp; mgr; l dNTP - Gemisch (jeweils 10 mM) und 188 ul Wasser zur Herstellung von 1 ml 2x LAMP - Puffer. Mix von Puls-Verwirbelung für 10 Sekunden. </li></ol> 4. Führen Sie Standard-LAMP-Reaktion <ol><li> Mix 12,5 ul 2x LAMP - Puffer (wie in Schritt 3 hergestellt; 40 mM Tris-HCl (pH 8,8), 20 mM KCl, 16 mM MgSO 4, 20 mM (NH 4) 2 SO 4, 0,2% Triton X-100, 1,6 M Trimethylglycin, 1.4 mM dNTP - Gemisch), 1,2 &amp; mgr; l Primer - Mix, 1 &amp; mgr; l Bst DNA - Polymerase (8 U / ul) und 5,3 ul Wasser Reaktionsmischung (20 ul) in einem 0,2 ml PCR - Röhrchen zu bilden. </li><li> Zugabe von 5 &amp; mgr; l DNA (aus Schritt 1 oder 2) in die 20 &amp; mgr; l Reaktionsgemisch und gut mischen. </li><li> Schließen Rohr und für 60 min in einem Wasserbad oder Heizblock bei 60 ° C inkubiert. Dies ist die optimale Reaktionstemperatur zuvor bestimmt. </li><li> In 5 ul 10x Gelladepuffer, um die Reaktion zu beenden. </li><li> Last 5 &amp; mgr; l Reaktionsprodukte zu einem 2% Agarosegel, gefärbt mit stain Nukleinsäure interkalierende. </li><li> Führen Gel bei 100 V für 35 min in 1x TBE-Puffer. </li><li> Visualisieren Sie die Ergebnisse durch UV-Licht. </li></ol> 5. Führen Sie LAMP Reaktion mit RekonstituiertesReagenzien <ol><li> Mischen Sie 125 ul von 10x Pol Puffer, 200 &amp; mgr; l von 5 M Trimethylglycin, 7,5 ul 1 M MgSO 4, 667,5 ul Wasser zur Herstellung von 1 ml Rekonstitution Puffer. Mix von Puls-Verwirbelung für 10 Sekunden. </li><li> Entfernen Sie Rohre, die die lyophilisierten Reagenzien aus dem versiegelten Aluminiumfolienbeutel enthalten. Sie nicht die Rohre verwenden, wenn die Aluminiumfolienbeutel nicht abgedichtet ist, oder wenn es beschädigt ist. </li><li> In 20 ul Rekonstitution Puffer in jedes Röhrchen lyophilisierten Reagenzien erneut zu suspendieren. </li><li> Mischen durch Pipettieren Puffer nach oben und unten 5-mal. Werfen Sie einen Blick um sicherzustellen, dass die lyophilisierten Reagenzien komplett neu aufgehängt sind. Das weiße Pulver sollte in der Röhre verschwinden. </li><li> In 5 ul DNA-Template (aus Schritt 1 oder 2) zu den rekonstituierten Reagenzien und gut mischen. </li><li> Schließen Rohr und für 60 min in einem Wasserbad oder Heizblock bei 60 ° C inkubiert. </li><li> In 5 ul 10x Gelladepuffer, um die Reaktion zu beenden. </li><li> Last 5 ul ReaktionsProdukte einem 2% Agarosegel, gefärbt mit Nukleinsäure interkalierende stain. </li><li> Führen Gel bei 100 V für 35 min in 1x TBE-Puffer. </li><li> Visualisieren Sie die Ergebnisse durch UV-Licht. </li></ol> 6. Führen Sie LAMP Reaktion mit Rekonstitution Puffer, der HNB oder Fluorescent interkalierende Farbstoff <ol><li> Mischungs 125 ul 10fach Pol Puffer, 200 &amp; mgr; l von 5 M Trimethylglycin, 7,5 ul 1 M MgSO 4, 7,5 ul 20 mM HNB (oder 12,5 &amp; mgr; l 100x fluoreszierenden interkalierenden Farbstoff) und 660 ul (oder 655 &amp; mgr; l) Wasser machen 1 ml Rekonstitution Puffer. Mix von Puls-Verwirbelung für 10 Sekunden. </li><li> Verwenden Sie das aufgelöste Puffer in Abschnitt 6 hergestellt, die Schritte 5.2 zu wiederholen - 5.6. </li><li> Visualisieren Sie die Ergebnisse mit dem bloßen Auge (Reaktion, die HNB) oder einem UV-Licht (Reaktion fluoreszierenden interkalierenden Farbstoff enthält). </li></ol> Führen 7. Echtzeit-LAMP-Reaktion mit Rohr Scanner <ol><li> In 5 ul DNA an die reconstituted Reagenzien fluoreszierenden interkalierenden Farbstoff, in der Nähe Rohr und legen Sie es auf das Rohr Scanner enthält. </li><li> Eingestellt Inkubationstemperatur auf 60 ° C. Messen der Fluoreszenz bei 520 nm für 60 min. </li></ol>

<ol>
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Diagn. 1 (112), (2012).</li><li>Pan, L., Zhang, L., Wang, G., Liu, Q. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Rapid,+sensitive+detection+of+the+ompB+gene+of+spotted+fever+group+rickettsiae+by+loop-mediated+isothermal+amplification.">Rapid, sensitive detection of the ompB gene of spotted fever group rickettsiae by loop-mediated isothermal amplification.</a> BMC Infect. Dis. 12 (254), (2012).</li><li>Mori, Y., Nagamine, K., Tomita, N., Notomi, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Detection+of+loop-mediated+isothermal+amplification+reaction+by+turbidity+derived+from+magnesium+pyrophosphate+formation.">Detection of loop-mediated isothermal amplification reaction by turbidity derived from magnesium pyrophosphate formation.</a> Biochem. Biophys. Res. Commun. 289 (1), 150-154 (2001).</li><li>Qiao, Y. M., 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=Loop-mediated+isothermal+amplification+for+rapid+detection+of+Bacillus+anthracis.spores.">Loop-mediated isothermal amplification for rapid detection of Bacillus anthracis.spores.</a> Biotechnol. Lett. 29 (12), 1939-1946 (2007).</li><li>Tomita, N., Mori, Y., Kanda, H., Notomi, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Loop-mediated+isothermal+amplification+(LAMP)+of+gene+sequences+and+simple+visual+detection+of+products.">Loop-mediated isothermal amplification (LAMP) of gene sequences and simple visual detection of products.</a> Nat. Protoc. 3 (5), 877-882 (2008).</li><li>Thekisoe, O. M., 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=Stability+of+Loop-Mediated+Isothermal+Amplification+(LAMP)+reagents+and+its+amplification+efficiency+on+crude+trypanosome+DNA+templates.">Stability of Loop-Mediated Isothermal Amplification (LAMP) reagents and its amplification efficiency on crude trypanosome DNA templates.</a> J. Vet. Med. Sci. 71 (4), 471-475 (2009).</li><li>Chen, H. W., Ching, W. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Development+of+loop-mediated+isothermal+amplification+assays+for+rapid+and+easy+detection+of+Coxiella+Burnetii.">Development of loop-mediated isothermal amplification assays for rapid and easy detection of Coxiella Burnetii.</a> J. Microbiol Methods. 107, 176-181 (2014).</li><li>Wang, D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+Comparison+of+In-House+Real-Time+LAMP+Assays+with+a+Commercial+Assay+for+the+Detection+of+Pathogenic+Bacteria.">A Comparison of In-House Real-Time LAMP Assays with a Commercial Assay for the Detection of Pathogenic Bacteria.</a> Molecules. 20 (6), 9487-9495 (2015).</li></ol>

Die Autoren haben nichts zu offenbaren.

Bisher haben wir eine empfindliche und spezifische LAMP - Targeting - Assay das Einsatzelement IS1111a 14. Das IS1111 Element wurde ausgewählt , weil es stark unter den verschiedenen Stämmen von C. konserviert burnetii und die hohe Anzahl der Kopien (7-110) in den Bakterien (Klee 2006). Unsere Ergebnisse zeigten , dass LAMP können etwa 25 Kopien des IS1111 Element erkennen, die so wenig wie eine chromosomale Kopie von Coxiella DNA korrelieren. In dieser...

Die kleine Gram-negative Bakterium Coxiella burnetii ist der Erreger des Q - Fiebers, das ein weltweit Zoonose ist. Durch den weltweiten Vertrieb von Q - Fieber und die hohe Infektiosität von C. burnetii, US - Militär- und Zivilpersonal im Ausland im Einsatz sind in Gefahr, in den Endemiegebieten infiziert. Q-Fieber manifestiert sich in zwei Formen: akute und chronische Infektionen. Akute Q-Fieber präsentiert sich mit grippeähnlichen Symptomen, Hepatitis oder Pneumonie, und ist in der Regel eine selbstlimitierend Krankheit mit einer niedrigen Sterblichkeit. Chronische Q-Fieber, während weniger verbreitet, führt oft zu Endokarditis, die eine viel höhere Mortalitätsrate hat , wenn 1,2 unbehandelt. Daher ist eine frühzeitige Diagnose führen eine geeignete Behandlung für die Patientenversorgung kritisch ist. Polymerase - Kettenreaktion (PCR) und quantitative Echtzeit - PCR (qPCR) Assays wurden zum Nachweis von C. entwickelt burnetii DNA in Zellkulturen und klinische Proben 3-5 &lt;/ Sup&gt;. Beide PCR und qPCR sind teuer und oft nicht ohne weiteres verfügbar in ressourcenbeschränkte Bereiche für die Routinearbeit. Ursprünglich von Notomi 6 beschrieben, Loop-vermittelte isothermen Amplifikation (LAMP) bietet eine alternative DNA - Verstärkungsverfahren. LAMP verwendet Bst DNA - Polymerase zusammen mit speziell entwickelten Primer - Sets Verschiebung DNA Synthese Strang, der mindestens sechs unabhängigen Regionen des Zielgens zu erkennen. Der signifikanteste Vorteil ist, dass LAMP-Amplifikation unter isothermischen Bedingungen auftritt. Daher ist nur ein Wasserbad, Heizblock oder ein Inkubator ist nicht erforderlich. Dieses Verfahren wurde verwendet 7-9 verschiedene rickettsial Pathogene zu erkennen. Visualisierung von amplifizierte DNA-Produkte durch Gelelektrophorese ist die genaueste Methode, die wahren Positiven von Fehlalarme aufgrund unspezifischer Amplifikation unterscheiden kann. Jedoch sind die in der Gelelektrophorese angewandten Verfahren nicht praktikabel für begrenzten Ressource-areas. Es wurden verschiedene alternative Verfahren entwickelt, um die Reaktionsprodukte zu detektieren. Diese alternativen, wie Trübung , abgeleitet von Magnesiumpyrophosphat Formation 10 oder unter Verwendung eines fluoreszierenden interkalierenden Farbstoff unter UV - Licht visualisiert werden 11,12 sind günstiger als ein Gel läuft. Die LAMP - Reagenzien waren einen Monat lang stabil , wenn sie bei 25 ° C und 37 ° C gelagert, die sind Umgebungstemperaturen in tropischen und subtropischen Ländern , in denen Q - Fieber endemisch 13 ist. Ein LAMP - Assay wurde in unserem Labor entwickelt , um das Vorhandensein von C. zu erkennen burnetii in Plasmaproben 14. Hier beschreiben wir ein einfaches Protokoll für die Herstellung der LAMP Reaktionsmischung aus dem lyophilisierten Reagenzien. Die lyophilisierten Reagenzien sind stabil für einen Monat, wenn bei RT gelagert. Wenn sie mit einem einfachen Visualisierungsverfahren kombiniert werden , ist dies eine ideale Methode zum Nachweis C. verwenden burnetii in einer begrenzten Ressource-Einstellung.

<table border="0" cellpadding="0" cellspacing="0" width="773">
	<tbody>
		<tr height="26">
			<td height="26" style="height:27px;width:215px;">LAMP primers</td>
			<td style="width:188px;">Eurofins MWG operon</td>
			<td style="width:131px;">10 nmol, salt free</td>
			<td style="width:240px;">Sequence designed by customer</td>
		</tr>
		<tr height="26">
			<td height="26" style="height:27px;width:215px;">Bst DNA polymerase</td>
			<td style="width:188px;">New England Biolabs</td>
			<td style="width:131px;">M0275L</td>
			<td style="width:240px;">8 units/ml</td>
		</tr>
		<tr height="26">
			<td height="26" style="height:27px;width:215px;">10X Thermo pol buffer</td>
			<td style="width:188px;">New England Biolabs</td>
			<td style="width:131px;">B9004S</td>
			<td style="width:240px;"></td>
		</tr>
		<tr height="26">
			<td height="26" style="height:27px;width:215px;">dNTP mixture</td>
			<td style="width:188px;">New England Biolabs</td>
			<td style="width:131px;">N0447L</td>
			<td style="width:240px;">10 mM each</td>
		</tr>
		<tr height="26">
			<td height="26" style="height:27px;width:215px;">Betaine</td>
			<td style="width:188px;">Sigma-Aldrich</td>
			<td style="width:131px;">B0300</td>
			<td style="width:240px;">5 M, Trimethylglycine</td>
		</tr>
		<tr height="26">
			<td height="26" style="height:27px;width:215px;">Magnesium Sulfate</td>
			<td style="width:188px;">Sigma-Aldrich</td>
			<td style="width:131px;">M3409-1ML</td>
			<td style="width:240px;">1 M</td>
		</tr>
		<tr height="26">
			<td height="26" style="height:27px;width:215px;">10X Bluejuice</td>
			<td style="width:188px;">Invitrogen</td>
			<td style="width:131px;">10816-015</td>
			<td style="width:240px;">gel loading buffer</td>
		</tr>
		<tr height="26">
			<td height="26" style="height:27px;width:215px;">SYBR green</td>
			<td style="width:188px;">Invitrogen</td>
			<td style="width:131px;">S7585</td>
			<td style="width:240px;">10,000X, visualize products in tubes</td>
		</tr>
		<tr height="26">
			<td height="26" style="height:27px;width:215px;">GelRed</td>
			<td style="width:188px;">Phenix Research Products</td>
			<td style="width:131px;">RGB-4103</td>
			<td style="width:240px;">10,000X, visualize products in gels</td>
		</tr>
		<tr height="26">
			<td height="26" style="height:27px;width:215px;">Lyophilized reagents</td>
			<td style="width:188px;">Gene Reach</td>
			<td style="width:131px;"></td>
			<td style="width:240px;"></td>
		</tr>
		<tr height="26">
			<td height="26" style="height:27px;width:215px;">Hydroxynaphthol blue</td>
			<td style="width:188px;">Fluka</td>
			<td style="width:131px;">33936-10G</td>
			<td style="width:240px;"></td>
		</tr>
		<tr height="26">
			<td height="26" style="height:27px;width:215px;">ESEQuant tube scanner</td>
			<td style="width:188px;">Qiagen</td>
			<td style="width:131px;"></td>
			<td style="width:240px;">real-time detection</td>
		</tr>
	</tbody>
</table>

the development of lyophilized loop-mediated isothermal amplification reagents for the detection of coxiella burnetii

Coxiella burnetii, der Agent Q - Fieber verursacht, ist ein obligat intrazelluläres Bakterium. PCR - basierten diagnostischen Assays wurden zum Nachweis von C. entwickelt burnetii DNA in Zellkulturen und klinischen Proben. PCR erfordert spezielle Ausrüstung und umfassende Schulung von Endanwendern, und daher ist es für Routinearbeiten vor allem in einem ressourcenbeschränkte Bereich nicht geeignet. Wir haben eine loop-vermittelte isothermische Amplifikation (LAMP) Assay entwickelt , um die Anwesenheit von C. nachzuweisen burnetii in Patientenproben. Dieses Verfahren wird bei einer einzigen Temperatur etwa 60 ° C in einem Wasserbad oder Heizblock durchgeführt. Die Empfindlichkeit dieses LAMP-Test ist sehr ähnlich wie PCR mit einer Nachweisgrenze von etwa 25 Kopien pro Reaktion. Dieser Bericht beschreibt die Herstellung der Reaktion lyophilisierten Reagenzien und Visualisierung der Ergebnisse mit hydroxynaphthol blau (HNB) oder einer UV-Lampe mit fluoreszierenden interkalierenden Farbstoff in der Reaktion verwendet wird. Die LAMP-Reagenzien waren lyophilized und bei Raumtemperatur (RT) einen Monat lang ohne Verlust der Detektionsempfindlichkeit gespeichert. Diese LAMP-Test ist besonders robust, da die Reaktionsgemischaufbereitung nicht komplexe Schritte beinhaltet. Diese Methode ist ideal für den Einsatz in begrenzten Ressource-Einstellungen, wo Q-Fieber endemisch ist.

Die lyophilisierten LAMP Reagenzien innerhalb der 0,2 - ml - Röhrchen enthält Bst DNA - Polymerase, Primer und dNTPs. 20 ul Rekonstitution Puffer wird verwendet , die lyophilisierten Reagenzien erneut zu suspendieren. Abbildung 1 zeigt die LAMP Reaktion führt auf Agarosegelen mit frisch zubereiteten Reagenzien und gefriergetrocknet Reagenzien. Das gefriergetrocknete Reagenz verringert nicht seine Aktivität. LAMP Reaktionen von beiden Reagenzien hergestellt w...

Watch this Scientific Journal Video about The Development of Lyophilized Loop-mediated Isothermal Amplification Reagents for the Detection of Coxiella burnetii at JoVE.com

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

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

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

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

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Immunology and Infection

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

10.4K Aufrufe.  Naval Medical Research Center. We described here a simple loop-mediated isothermal amplification (LAMP) method using lyophilized reagents for the detection of C. burnetii in patient samples.

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

Detection of Infectious Virus from Field-collected Mosquitoes by Vero Cell Culture Assay

Mosquitoes transmit a number of distinct viruses including important human pathogens such as West Nile virus, dengue virus, and chickungunya virus. Many of these viruses have intensified in their endemic ranges and expanded to new territories, necessitating effective surveillance and control programs to respond to these threats. One strategy to monitor virus activity involves collecting large numbers of mosquitoes from endemic sites and testing them for viral infection. In this article, we describe how to handle, process, and screen field-collected mosquitoes for infectious virus by Vero cell culture assay. Mosquitoes are sorted by trap location and species, and grouped into pools containing &le;50 individuals. Pooled specimens are homogenized in buffered saline using a mixer-mill and the aqueous phase is inoculated onto confluent Vero cell cultures (Clone E6). Cell cultures are monitored for cytopathic effect from days 3-7 post-inoculation and any viruses grown in cell culture are identified by the appropriate diagnostic assays. By utilizing this approach, we have isolated 9 different viruses from mosquitoes collected in Connecticut, USA, and among these, 5 are known to cause human disease. Three of these viruses (West Nile virus, Potosi virus, and La Crosse virus) represent new records for North America or the New England region since 1999. The ability to detect a wide diversity of viruses is critical to monitoring both established and newly emerging viruses in the mosquito population.

We describe a method to process and screen field-collected mosquitoes for a diversity of viruses by Vero cell culture assay. By employing this technique, we have detected 9 different viruses from 4 taxonomic families in mosquitoes collected in Connecticut.

Nachweis von infektiösen Viren aus Field-gesammelt Moskitos von Vero Cell Culture Assay

Mosquitoes transmit a number of distinct viruses including important human pathogens such as West Nile virus, dengue virus, and chickungunya virus. Many ...

Forschung

Immunologie und Infektion

Generation of Recombinant Arenavirus for Vaccine Development in FDA-Approved Vero Cells

The development and implementation of arenavirus reverse genetics represents a significant breakthrough in the arenavirus field 4. The use of cell-based arenavirus minigenome systems together with the ability to generate recombinant infectious arenaviruses with predetermined mutations in their genomes has facilitated the investigation of the contribution of viral determinants to the different steps of the arenavirus life cycle, as well as virus-host interactions and mechanisms of arenavirus pathogenesis 1, 3, 11 . In addition, the development of trisegmented arenaviruses has permitted the use of the arenavirus genome to express additional foreign genes of interest, thus opening the possibility of arenavirus-based vaccine vector applications 5 . Likewise, the development of single-cycle infectious arenaviruses capable of expressing reporter genes provides a new experimental tool to improve the safety of research involving highly pathogenic human arenaviruses 16 . The generation of recombinant arenaviruses using plasmid-based reverse genetics techniques has so far relied on the use of rodent cell lines 7,19 , which poses some barriers for the development of Food and Drug Administration (FDA)-licensed vaccine or vaccine vectors. To overcome this obstacle, we describe here the efficient generation of recombinant arenaviruses in FDA-approved Vero cells.

Rescue of recombinant arenaviruses from cloned cDNAs, an approach referred to as reverse genetics, allows researchers to investigate the role of specific viral gene products, as well as the contribution of their different specific domains and residues, to many different aspects of the biology of arenavirus. Likewise, reverse genetics techniques in FDA-approved cell lines (Vero) for vaccine development provides novel possibilities for the generation of effective and safe vaccines to combat human pathogenic arenaviruses.

Erzeugung von rekombinanten Arenavirus für die Impfstoffentwicklung in FDA-zugelassenen Vero-Zellen

The development and implementation of arenavirus reverse genetics represents a significant breakthrough in the arenavirus field  4. The use of cell-based ...

Assessing the Development of Murine Plasmacytoid Dendritic Cells in Peyer's Patches Using Adoptive Transfer of Hematopoietic Progenitors

This protocol details a method to analyze the ability of purified hematopoietic progenitors to generate plasmacytoid dendritic cells (pDC) in intestinal Peyer&#39;s patch (PP). Common dendritic cell progenitors (CDPs, lin- c-kitlo CD115+ Flt3+) were purified from the bone marrow of C57BL6 mice by FACS and transferred to recipient mice that lack a significant pDC population in PP; in this case, Ifnar-/- mice were used as the transfer recipients. In some mice, overexpression of the dendritic cell growth factor Flt3 ligand (Flt3L) was enforced prior to adoptive transfer of CDPs, using hydrodynamic gene transfer (HGT) of Flt3L-encoding plasmid. Flt3L overexpression expands DC populations originating from transferred (or endogenous) hematopoietic progenitors. At 7-10 days after progenitor transfer, pDCs that arise from the adoptively transferred progenitors were distinguished from recipient cells on the basis of CD45 marker expression, with pDCs from transferred CDPs being CD45.1+ and recipients being CD45.2+. The ability of transferred CDPs to contribute to the pDC population in PP and to respond to Flt3L was evaluated by flow cytometry of PP single cell suspensions from recipient mice. This method may be used to test whether other progenitor populations are capable of generating PP pDCs. In addition, this approach could be used to examine the role of factors that are predicted to affect pDC development in PP, by transferring progenitor subsets with an appropriate knockdown, knockout or overexpression of the putative developmental factor and/or by manipulating circulating cytokines via HGT. This method may also allow analysis of how PP pDCs affect the frequency or function of other immune subsets in PPs. A unique feature of this method is the use of Ifnar-/- mice, which show severely depleted PP pDCs relative to wild type animals, thus allowing reconstitution of PP pDCs in the absence of confounding effects from lethal irradiation.

This protocol describes experimental procedures to assess the differentiation of plasmacytoid dendritic cells in Peyer&#8217;s patch from common dendritic cell progenitors, using techniques involving FACS-mediated cell isolation, hydrodynamic gene transfer, and flow analysis of immune subsets in Peyer&#8217;s patch.

Die Beurteilung der Entwicklung der Murine Plasmazytoide dendritischen Zellen in Peyer-Patches mit Adoptiv Übertragung von hämatopoetischen Vorläuferzellen

This protocol details a method to analyze the ability of purified hematopoietic progenitors to generate plasmacytoid dendritic cells (pDC) in intestinal ...

In Vitro Analysis of Myd88-mediated Cellular Immune Response to West Nile Virus Mutant Strain Infection

An attenuated West Nile virus (WNV), a nonstructural (NS) 4B-P38G mutant, induced higher innate cytokine and T cell responses than the wild-type WNV in mice. Recently, myeloid differentiation factor 88 (MyD88) signaling was shown to be important for initial T cell priming and memory T cell development during WNV NS4B-P38G mutant infection. In this study, two flow cytometry-based methods &#8211; an in vitro T cell priming assay and an intracellular cytokine staining (ICS) &#8211; were utilized to assess dendritic cells (DCs) and T cell functions. In the T cell priming assay, cell proliferation was analyzed by flow cytometry following co-culture of DCs from both groups of mice with carboxyfluorescein succinimidyl ester (CFSE) - labeled CD4+ T cells of OTII transgenic mice. This approach provided an accurate determination of the percentage of proliferating CD4+ T cells with significantly improved overall sensitivity than the traditional assays with radioactive reagents. A microcentrifuge tube system was used in both cell culture and cytokine staining procedures of the ICS protocol. Compared to the traditional tissue culture plate-based system, this modified procedure was easier to perform at biosafety level (BL) 3 facilities. Moreover, WNV- infected cells were treated with paraformaldehyde in both assays, which enabled further analysis outside BL3 facilities. Overall, these in vitro immunological assays can be used to efficiently assess cell-mediated immune responses during WNV infection.

In Vitro Analysis of Myd88-mediated Cellular Immune Response to West Nile Virus Mutant Strain Infection

Two flow cytometry-based methods &#8211; an in vitro T cell priming assay and intracellular cytokine staining were utilized to measure antigen presenting capacity of dendritic cells and antigen-specific T cell responses to a West Nile virus mutant infection in mice.

In-vitro-Analyse Myd88-vermittelte zelluläre Immunantwort gegen das West-Nil-Virus-Infektion Mutantenstamm

An attenuated West Nile virus (WNV), a nonstructural (NS) 4B-P38G mutant, induced higher innate cytokine and T cell responses than the wild-type WNV in ...

Development of an in vitro model system for studying the interaction of Equus caballus IgE with its high-affinity receptor Fc&#949;RI

The interaction of IgE with its high-affinity Fc receptor (Fc&#949;RI) followed by an antigenic challenge is the principal pathway in IgE mediated allergic reactions. As a consequence of the high affinity binding between IgE and Fc&#949;RI, along with the continuous production of IgE by B cells, allergies usually persist throughout life, with currently no permanent cure available. Horses, especially race horses, which are commonly inbred, are a species of mammals that are very prone to the development of hypersensitivity responses, which can seriously affect their performance. Physiological responses to allergic sensitization in horses mirror that observed in humans and dogs. In this paper we describe the development of an in situ assay system for the quantitative assessment of the release of mediators of the allergic response pertaining to the equine system. To this end, the gene encoding equine Fc&#949;RI&#945; was transfected into and expressed onto the surface of parental Rat Basophil Leukemia (RBL-2H3.1) cells. The gene product of the transfected equine &#945;-chain formed a functional receptor complex with the endogenous rat &#946;- and &#947;-chains 1. The resultant assay system facilitated an assessment of the quantity of mediator secreted from equine Fc&#949;RI&#945; transfected RBL-2H3.1 cells following sensitization with equine IgE and antigenic challenge using &#946;-hexosaminidase release as a readout 2, 3. Mediator release peaked at 36.68% &#177; 4.88% at 100 ng ml-1 of antigen. This assay was modified from previous assays used to study human and canine allergic responses 4, 5. We have also shown that this type of assay system has multiple applications for the development of diagnostic tools and the safety assessment of potential therapeutic intervention strategies in allergic disease 6, 2, 3.

The current study describes the development and applications of a genetically engineered assay system based on the transfection of rat basophilic leukemia cells with the equine Fc&#949;RI&#945; gene. Transfected cells express a functional receptor where the release of mediators of the allergic response can be activated by IgE and antigen.

Entwicklung eines<em&gt; In vitro</em&gt; Modellsystem für die Untersuchung der Wechselwirkung von<em&gt; Equus</em&gt;<em&gt; Caballus</em&gt; IgE mit seinen hochaffinen Rezeptors FcsRI

The interaction of IgE with its high-affinity Fc receptor (Fc&#949;RI) followed by an antigenic challenge is the principal pathway in IgE mediated ...

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 ...

Generation and Multi-phenotypic High-content Screening of Coxiella burnetii Transposon Mutants

Invasion and colonization of host cells by bacterial pathogens depend on the activity of a large number of prokaryotic proteins, defined as virulence factors, which can subvert and manipulate key host functions. The study of host/pathogen interactions is therefore extremely important to understand bacterial infections and develop alternative strategies to counter infectious diseases. This approach however, requires the development of new high-throughput assays for the unbiased, automated identification and characterization of bacterial virulence determinants. Here, we describe a method for the generation of a GFP-tagged mutant library by transposon mutagenesis and the development of high-content screening approaches for the simultaneous identification of multiple transposon-associated phenotypes. Our working model is the intracellular bacterial pathogen Coxiellaburnetii, the etiological agent of the zoonosis Q fever, which is associated with severe outbreaks with a consequent health and economic burden. The obligate intracellular nature of this pathogen has, until recently, severely hampered the identification of bacterial factors involved in host pathogen interactions, making of Coxiella the ideal model for the implementation of high-throughput/high-content approaches.

Generation and Multi-phenotypic High-content Screening of Coxiella burnetii Transposon Mutants

Coxiella burnetii is an obligate intracellular Gram-negative bacterium responsible for the zoonotic disease Q fever. Here we describe methods for the generation of Coxiella fluorescent transposon mutants as well as the automated identification and analysis of the resulting internalization, replication and cytotoxic phenotypes.

Generation und Multi-phänotypischen High-Content-Screening<em&gt; Coxiella burnetii</em&gt; Transposon-Mutanten

Invasion and colonization of host cells by bacterial pathogens depend on the activity of a large number of prokaryotic proteins, defined as virulence ...

Qualitative and Quantitative Assays for Detection and Characterization of Protein Antimicrobials

Initial evaluations of large microbial libraries for potential producers of novel antimicrobial proteins require both qualitative and quantitative methods to screen for target enzymes prior to investing greater research effort and resources. The goal of this protocol is to demonstrate two complementary assays for conducting these initial evaluations. The microslide diffusion assay provides an initial or simple detection screen to enable the qualitative and rapid assessment of proteolytic activity against an array of both viable and heat-killed bacterial target substrates. As a counterpart, the increased sensitivity and reproducibility of the dye-release assay provides a quantitative platform for evaluating and comparing environmental influences affecting the hydrolytic activity of protein antimicrobials. The ability to label specific heat-killed cell culture substrates with Remazol brilliant blue R dye expands this capability to tailor the dye-release assay to characterize enzymatic activity of interest.

Here, we present protocols to rapidly screen and characterize enzymes for antimicrobial activity. The microslide diffusion assay and the dye-release assay utilize target bacterial substrates for qualitative and quantitative enzymatic activity evaluation.

Qualitative und quantitative Assays zur Detektion und Charakterisierung von Protein Antimikrobielle

Initial evaluations of large microbial libraries for potential producers of novel antimicrobial proteins require both qualitative and quantitative methods ...

Applying Fluorescence Resonance Energy Transfer (FRET) to Examine Effector Translocation Efficiency by Coxiella burnetii during siRNA Silencing

Coxiella burnetii, the causative agent of Q fever, is an intracellular pathogen that relies on a Type IV Dot/Icm Secretion System to establish a replicative niche. A cohort of effectors are translocated through this system into the host cell to manipulate host processes and allow the establishment of a unique lysosome-derived vacuole for replication. The method presented here involves the combination of two well-established techniques: specific gene silencing using siRNA and measurement of effector translocation using a FRET-based substrate that relies on &#946;-lactamase activity. Applying these two approaches, we can begin to understand the role of host factors in bacterial secretion system function and effector translocation. In this study we examined the role of Rab5A and Rab7A, both important regulators of the endocytic trafficking pathway. We demonstrate that silencing the expression of either protein results in a decrease in effector translocation efficiency. These methods can be easily modified to examine other intracellular and extracellular pathogens that also utilize secretion systems. In this way, a global picture of host factors involved in bacterial effector translocation may be revealed.

Applying Fluorescence Resonance Energy Transfer FRET to Examine Effector Translocation Efficiency by Coxiella burnetii during siRNA Silencing

Investigating the interactions between bacterial pathogens and their hosts is an important area of biological research. Here, we describe the necessary techniques to measure effector translocation by Coxiella burnetii during siRNA gene silencing using BlaM substrate.

Anwenden von Fluorescence Resonance Energy Transfer (FRET) zu untersuchen Effektor Translokation Effizienz durch<em&gt; Coxiella burnetii</em&gt; Während siRNA Silencing

Coxiella burnetii, the causative agent of Q fever, is an intracellular pathogen that relies on a Type IV Dot/Icm Secretion System to establish a ...

Development of a More Sensitive and Specific Chromogenic Agar Medium for the Detection of Vibrio parahaemolyticus and Other Vibrio Species

Foodborne infections in the US caused by Vibrio species have shown an upward trend. In the genus Vibrio, V. parahaemolyticus is responsible for the majority of Vibrio-associated infections. Thus, accurate differentiation among Vibrio spp. and detection of V. parahaemolyticus is critically important to ensure the safety of our food supply. Although molecular techniques are increasingly common, culture-depending methods are still routinely done and they are considered standard methods in certain circumstances. Hence, a novel chromogenic agar medium was tested with the goal of providing a better method for isolation and differentiation of clinically relevant Vibrio spp. The protocol compared the sensitivity, specificity and detection limit for the detection of V. parahaemolyticus between the new chromogenic medium and a conventional medium. Various V. parahaemolyticus strains (n=22) representing diverse serotypes and source of origins were used. They were previously identified by Food and Drug Administration (FDA) and Centers for Disease Control and Prevention (CDC), and further verified in our laboratory by tlh-PCR. In at least four separate trials, these strains were inoculated on the chromogenic agar and thiosulfate-citrate-bile salts-sucrose (TCBS) agar, which is the recommended medium for culturing this species, followed by incubation at 35-37 &#176;C for 24-96 hr. Three V. parahaemolyticus strains (13.6%) did not grow optimally on TCBS, nonetheless exhibited green colonies if there was growth. Two strains (9.1%) did not yield the expected cyan colonies on the chromogenic agar. Non-V. parahaemolyticus strains (n=32) were also tested to determine the specificity of the chromogenic agar. Among these strains, 31 did not grow or exhibited other colony morphologies. The mean recovery of V. parahaemolyticus on the chromogenic agar was ~96.4% relative to tryptic soy agar supplemented with 2% NaCl. In conclusion, the new chromogenic agar is an effective medium to detect V. parahaemolyticus and to differentiate it from other vibrios.

Development of a More Sensitive and Specific Chromogenic Agar Medium for the Detection of Vibrio parahaemolyticus and Other Vibrio Species

Detection and isolation of clinically relevant Vibrio species require selective and differential culture media. This study evaluated the ability of a new chromogenic medium to detect and identify V. parahaemolyticus and other related species. The new medium was found to have better sensitivity and specificity than the conventional medium.

Entwicklung eines sensitiven und spezifischen chromogenen Agar Medium zum Nachweis von<em&gt; Vibrio parahaemolyticus</em&gt; Und andere<em&gt; Vibrio</em&gt; Arten

Foodborne infections in the US caused by Vibrio species have shown an upward trend. In the genus Vibrio, V. parahaemolyticus is responsible for the ...