Questa ricerca è stata sostenuta dal Naval Medical Research Center, la ricerca unità di lavoro 6000.RAD1.J.A0310. Le opinioni espresse in questo articolo sono quelle degli autori e non riflettono necessariamente la politica ufficiale o la posizione del Dipartimento della Marina, Dipartimento della Difesa, o il governo degli Stati Uniti. Wei-Mei Ching è un dipendente del governo degli Stati Uniti. Questo lavoro è stato preparato come parte dei suoi doveri d&#39;ufficio. Titolo 17 USC §105 prevede che &#39;La protezione del copyright sotto questo titolo non è disponibile per qualsiasi lavoro del governo degli Stati Uniti.&#39; Titolo 17 USC §101 definisce un lavoro del governo degli Stati Uniti come un lavoro preparato dal membro del servizio militare o dipendente del governo degli Stati Uniti, come parte delle funzioni ufficiali di quella persona.

1. Preparare plasmidi DNA diluizioni come standard per LAMP Reazione <ol><li> Utilizzare uno spettrofotometro per misurare la densità ottica (OD) a 260 nm per determinare il plasmide (contenente gene target IS1111a di C. burnetii RSA 493) concentrazione di DNA. Un OD 260 di 1 equivale a 50 mg / mL di DNA. </li><li> Convertire la quantità di DNA plasmide nel numero di copie. Poiché la dimensione del plasmide è 6.330 bp, il peso molecolare di questo plasmide è 4,1 x 10 6 g (6.330 bp x 649 g / bp). La concentrazione di DNA del plasmide è 34,2 ng / ml (come determinato dal punto 1.1). 1 ml di questo campione di DNA contiene 34,2 ng di DNA plasmide, pari a 5 x 10 9 copie (34,2 x 10 -9 g / 4,1 x 10 6 gx 6,02 x 10 23) di DNA. </li><li> Aggiungere 10 ml di DNA plasmidico (5 x 10 9 copie / ml) a 90 ml di acqua per una diluizione di 10 volte per fare un campione di DNA di 5 x 10 8 copie / ml. </li><li> Ripetere passaggio 1.3 per preparare campioni di DNA di 5 x 10 7, 5 x 10 6, 5 x 10 5, 5 x 10 4, 5 x 10 3, 5 x 10 2, 5 x 10 1 e 5 x 10 0 copie / ul. </li></ol> 2. Preparare modello di DNA da campioni per la lampada di reazione <ol><li> Eseguire l&#39;estrazione del DNA da campioni di plasma umano utilizzando un kit mini DNA commerciale secondo il protocollo del produttore. Utilizzare un totale di 200 campioni microlitri per l&#39;estrazione ed eluire DNA estratto in un volume di 20 ml. </li></ol> 3. Preparare 2x Buffer LAMP Reazione <ol><li> Mescolare 200 ml di 10x Pol Buffer, 320 ml di 5 M trimetilglicina, 12 ml di 1 M MgSO 4, 280 ml ​​di miscela dNTP (10 mm ciascuno) e 188 microlitri di acqua per fare 1 ml di tampone 2x LAMP. Miscelare impulso-vortex per 10 secondi. </li></ol> 4. Eseguire lampada standard di reazione <ol><li> Mescolare 12,5 ml di 2x LATampone MP (come preparato al punto 3; 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 trimetilglicina, 1.4 mM miscela dNTP), 1,2 ml di miscela di primer, 1 ml di polimerasi Bst DNA (8 U / ml), e 5,3 l di acqua per fare miscela di reazione (20 ml) in un tubo di 0,2 ml PCR. </li><li> Aggiungere 5 ml di DNA (dal punto 1 o 2) alla miscela di reazione di 20 microlitri e mescolare bene. </li><li> Chiudere tubo e incubare a 60 ° C per 60 minuti in un bagnomaria o riscaldamento. Questa è la temperatura di reazione ottimale determinata in precedenza. </li><li> Aggiungere 5 ml di 10x tampone di caricamento del gel di interrompere la reazione. </li><li> Carico 5 microlitri di prodotti di reazione di un gel di agarosio al 2% colorato con intercalanti macchia dell&#39;acido nucleico. </li><li> Eseguire gel a 100 V per 35 min in tampone 1x TBE. </li><li> Visualizzare i risultati di raggi UV. </li></ol> 5. Eseguire Reazione lampada con ricostituitoreagenti <ol><li> Mescolare 125 ml di 10x Pol Buffer, 200 ml di 5 M trimetilglicina, 7,5 ml di 1 M MgSO 4, 667.5 ml di acqua per fare 1 ml di tampone di ricostituzione. Miscelare impulso-vortex per 10 secondi. </li><li> Rimuovere i tubi che contengono i reagenti liofilizzati dal sacchetto di alluminio sigillato. Non utilizzare i tubi se la borsa foglio di alluminio non è sigillato o se è danneggiato. </li><li> Aggiungere 20 ml di tampone di ricostituzione in ciascuna provetta per risospendere reagenti liofilizzati. </li><li> Mescolare pipettando tampone su e giù per 5 volte. Date un&#39;occhiata per assicurarsi che i reagenti liofilizzati sono completamente ri-sospesi. La polvere bianca dovrebbe scomparire nel tubo. </li><li> Aggiungere 5 ml di DNA stampo (dal punto 1 o 2) per i reagenti ricostituiti e mescolare bene. </li><li> Chiudere tubo e incubare a 60 ° C per 60 minuti in un bagnomaria o riscaldamento. </li><li> Aggiungere 5 ml di 10x tampone di caricamento del gel di interrompere la reazione. </li><li> Carico 5 ml di reazioneprodotti ad un gel di agarosio al 2% colorato con intercalanti macchia dell&#39;acido nucleico. </li><li> Eseguire gel a 100 V per 35 min in tampone 1x TBE. </li><li> Visualizzare i risultati di raggi UV. </li></ol> 6. Eseguire LAMP Reazione con tampone di ricostituzione contenenti HNB o fluorescente intercalante Dye <ol><li> Mescolare 125 ml di 10x Pol Buffer, 200 ml di 5 M trimetilglicina, 7,5 ml di 1 M MgSO 4, 7,5 ml di 20 mm HNB (o 12,5 ml di 100x fluorescente intercalante colorante) e 660 ml (o 655 ml) di acqua a fare 1 ml di tampone di ricostituzione. Miscelare impulso-vortex per 10 secondi. </li><li> Utilizzare il buffer ricostituito preparato nella sezione 6 di ripetere i passi 5.2 - 5.6. </li><li> Visualizzare i risultati ad occhio nudo (reazione contenente HNB) o una luce UV (reazione contenente colorante intercalante fluorescente). </li></ol> 7. Eseguire in tempo reale reazione lampada con tubo Scanner <ol><li> Aggiungere 5 microlitri DNA alla reconstitutreagenti ED contenenti colorante fluorescente intercalante, chiudere il tubo e inserirlo allo scanner tubo. </li><li> Impostare temperatura di incubazione a 60 ° C. Misurare la fluorescenza a 520 nm per 60 min. </li></ol>

<ol>
	<li>Anderson, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Diagnosis+and+management+of+Q+fever+United+States,+2013:+recommendations+from+CDC+and+the+Q+Fever+Working+Group.">Diagnosis and management of Q fever United States, 2013: recommendations from CDC and the Q Fever Working Group.</a> MMWR Recomm. Rep. 62 (3), 1-30 (2013).</li><li>Rolain, J. M., Boulos, A., Mallet, M. N., Raoult, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Correlation+between+ratio+of+serum+doxycycline+concentration+to+MIC+and+rapid+decline+of+antibody+levels+during+treatment+of+Q+fever+endocarditis.">Correlation between ratio of serum doxycycline concentration to MIC and rapid decline of antibody levels during treatment of Q fever endocarditis.</a> Antimicrob. 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Vaccine Immunol. 17 (2), 286-290 (2010).</li><li>Turra, M., Chang, G., Whybrow, D., Higgins, G., Qiao, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Diagnosis+of+acute+Q+fever+by+PCR+on+sera+during+a+recent+outbreak+in+rural+South+Australia.">Diagnosis of acute Q fever by PCR on sera during a recent outbreak in rural South Australia.</a> Ann. N Y Acad. Sci. 1078, 566-569 (2006).</li><li>Notomi, T., 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+of+DNA.">Loop-mediated isothermal amplification of DNA.</a> Nucleic Acids Res. 28 (12), (2000).</li><li>Paris, D. H., Blacksell, S. D., Newton, P. N., Day, N. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Simple,+rapid+and+sensitive+detection+of+Orientia+tsutsugamushi.+by+loo-isothermal+DNA+amplification.">Simple, rapid and sensitive detection of Orientia tsutsugamushi. by loo-isothermal DNA amplification.</a> Trans. R. Soc. Trop. Med. Hyg. 102 (12), 1239-1246 (2008).</li><li>Huber, E., 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+assay+targeting+the+47-kDa+gene+of+Orientia+tsutsugamushi.:+A+rapid+and+sensitive+alternative+to+real-time+PCR.">Loop-mediated isothermal amplification assay targeting the 47-kDa gene of Orientia tsutsugamushi.: A rapid and sensitive alternative to real-time PCR.</a> J. Med. Microb. 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>

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In precedenza, abbiamo sviluppato un saggio LAMP sensibile e specifico mira l&#39;elemento di inserimento IS1111a 14. L&#39;elemento IS1111 è stato scelto perché è altamente conservata tra i diversi ceppi di C. burnetii e il suo alto numero di copie (7-110) nei batteri (Klee 2006). I nostri risultati hanno mostrato che LAMP può rilevare circa 25 copie dell&#39;elemento IS1111, che può correlare il meno una copia cromosomale di Coxiella DNA. In questo studio, p...

Il piccolo batterio Gram-negativi Coxiella burnetii è l&#39;agente eziologico della febbre Q, che è una zoonosi in tutto il mondo. A causa della distribuzione a livello mondiale di febbre Q e l&#39;alta infettività di C. burnetii, militari e civili personale statunitense dispiegate all&#39;estero sono a rischio di infezione nelle zone endemiche. La febbre Q si manifesta in due forme: infezioni acute e croniche. Acuta febbre Q si presenta con sintomi simil-influenzali, l&#39;epatite, o polmonite, ed è di solito una malattia autolimitante con un basso tasso di mortalità. Cronica febbre Q, mentre meno diffuso, si traduce spesso in endocardite, che ha un tasso di mortalità molto più alto se non trattata 1,2. Pertanto, la diagnosi precoce per guidare un trattamento appropriato è fondamentale per la cura del paziente. Reazione a catena della polimerasi (PCR) e in tempo reale PCR quantitativa (qPCR) test sono stati sviluppati per la rilevazione C. DNA burnetii in colture cellulari e campioni clinici 3-5 &lt;/ Sup&gt;. Sia PCR e qPCR sono costose e spesso non facilmente disponibili in aree con risorse limitate per il lavoro di routine. Originariamente descritto da Notomi 6, l&#39;amplificazione isotermica loop-mediata (LAMP) offre un metodo alternativo amplificazione del DNA. LAMP utilizza polimerasi Bst DNA per la sintesi del DNA filone spostamento lungo con i set di primer appositamente progettati che riconoscono almeno sei regioni indipendenti del gene bersaglio. Il vantaggio più significativo di LAMP è che l&#39;amplificazione avviene in condizioni isoterme. Pertanto, è necessario solo un bagno d&#39;acqua, blocco di riscaldamento o di un incubatore. Questo metodo è stato utilizzato per rilevare diversi patogeni rickettsie 7-9. Visualizzazione dei prodotti di DNA amplificati mediante elettroforesi su gel è il metodo più accurato che può differenziare i veri positivi da falsi positivi a causa di amplificazione non specifica. Tuttavia le procedure necessarie per elettroforesi su gel non sono pratici per ar risorse limitateEAS. Diversi metodi alternativi sono stati sviluppati per rilevare i prodotti di reazione. Queste alternative, come torbidità derivante dalla formazione di magnesio pirofosfato 10 o utilizzando un colorante intercalante fluorescente da visualizzare sotto luce UV 11,12 sono più favorevoli di esecuzione di un gel. I reagenti LAMP erano stabile per un mese se conservato a 25 ° C e 37 ° C, che sono temperature ambientali nei paesi tropicali e sub-tropicali, dove la febbre Q è endemica 13. Un test LAMP stato sviluppato nel nostro laboratorio per rilevare la presenza di C. burnetii in campioni di plasma 14. Qui si descrive un protocollo semplice per la preparazione della miscela di reazione LAMP dai reagenti liofilizzati. I reagenti liofilizzati sono stabili per un mese se conservati a RT. Quando combinato con un metodo di visualizzazione facile, questo è un metodo ideale da utilizzare per la rilevazione C. burnetii in un ambiente risorse limitate.

<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, l&#39;agente che causa la febbre Q, è un batterio intracellulare obbligato. Saggi diagnostici basati sulla PCR sono stati sviluppati per la rilevazione C. DNA burnetii in colture cellulari e campioni clinici. PCR richiede attrezzature specializzate ed estesa formazione degli utenti finali, e quindi non è adatto per il lavoro di routine specialmente in una zona risorse limitate. Abbiamo sviluppato un saggio loop-mediata di amplificazione isotermica (LAMP) per rilevare la presenza di C. burnetii in campioni di pazienti. Questo metodo viene effettuata ad una sola temperatura di circa 60 ° C in un bagnomaria o riscaldamento. La sensibilità di questo test LAMP è molto simile a PCR con un limite di rilevazione di circa 25 copie per reazione. La relazione descrive la preparazione della reazione con reagenti liofilizzati e visualizzazione dei risultati usando blu di idrossinaftolo (HNB) o una lampada UV con colorante fluorescente intercalante nella reazione. I reagenti LAMP erano lyophilized e conservato a temperatura ambiente (RT) per un mese senza perdita di sensibilità di rilevazione. Questo test è particolarmente robusta LAMP perché la preparazione della miscela di reazione non comporta complessi passaggi. Questo metodo è ideale per l&#39;utilizzo in ambienti con risorse limitate, dove la febbre Q è endemica.

I reagenti LAMP liofilizzati all&#39;interno del tubo 0,2 ml contiene polimerasi Bst DNA, primer, e dNTP. 20 microlitri di tampone di ricostituzione è usato per risospendere i reagenti liofilizzati. La Figura 1 mostra i risultati di reazione LAMP su gel di agarosio con reagenti appena preparati e reagenti liofilizzati. Il reagente liofilizzato non riduce la sua attività. Reazioni LAMP preparati da entrambi i reagenti in grado di rilevare 25 copie del DNA stamp...

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

Lo sviluppo del liofilizzato Loop-mediate isotermici amplificazione reagenti per la rilevazione di<em&gt; Burnetii Coxiella</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 Views.  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.

Video: 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.

Il rilevamento del virus infettivo da Campo-zanzare raccolte mediante test coltura cellulare Vero

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

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Immunologia e infezioni

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.

Generazione di Arenavirus ricombinante per lo sviluppo del vaccino nel approvati dalla FDA cellule Vero

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.

Valutare lo sviluppo delle cellule murine plasmocitoidi dendritiche in placche del Peyer Utilizzando trasferimento adottivo di ematopoietiche Progenitori

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 Analisi Vitro di Myd88 mediata Cellular Immune Response to West Nile virus mutante Strain Infezione

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.

Sviluppo di un<em&gt; In vitro</em&gt; Sistema modello per studiare l&#39;interazione tra<em&gt; Equus</em&gt;<em&gt; Caballus</em&gt; IgE con il suo recettore ad alta affinità FcεRI

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.

Isotermico di amplificazione (lampada) Assays Loop-mediata per rilevamento delle specie-specifica<em&gt; Eimeria</em&gt; Che infettano Polli

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 e Multi-fenotipica Screening-Alto contenuto di<em&gt; Coxiella burnetii</em&gt; Mutants transposon

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.

Saggi qualitativi e quantitativi per il rilevamento e la caratterizzazione di proteine ​​antimicrobici

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.

Applicando Fluorescence Resonance Energy Transfer (FRET) per esaminare Effector Translocation efficienza da<em&gt; Burnetii Coxiella</em&gt; Durante 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.

Sviluppo di un più sensibile e specifica Chromogenic Agar Media per la rilevazione di<em&gt; Parahaemolyticus Vibrio</em&gt; E Altro<em&gt; Vibrio</em&gt; Specie

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

Lo sviluppo del liofilizzato Loop-mediate isotermici amplificazione reagenti per la rilevazione di

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