The authors thank the Ellison Medical Foundation for their support. We wish also to thank members of the Abby Dernburg laboratory for assistance with using the wormsorter.

1. La obtención de una Cultura Synchronized animales adultos jóvenes <ol><li> Crecer gusanos en varias NGM placas sembradas con OP50-1 E. bacterias coli (10x concentrado de un cultivo saturado) hasta muchos gusanos alcanzaron la etapa grávido. </li><li> Tratar a los animales grávidos con solución huevo-prep para obtener un cultivo sincronizado (huevos). </li><li> Huevos Placa en varios de 60 mm NGM placas sembradas con 10x OP50-1 concentrado a una densidad de aproximadamente 150 a 200 huevos / placa. </li><li> Incubar las placas a 25 ° C durante 2 días (hasta que los gusanos han llegado a la L4 - etapa Adulto joven). </li></ol> 2. Preparación de las placas de Pseudomonas aeruginosa y la infección de Worms <ol><li> En el día de la huevo-PREP (paso 1.1) inocular un cultivo PA14 :: GFP en 2 ml de medio que contenía rifampicina B de King a una concentración final de 100 mg / ml. Incubar el cultivo a 37 ° C con agitación O / N. </li><li> Placa del PA14 :: GFP cultura en el mayor número de placas Killing Lento (SKP), según sea necesario para el ensayo. En cada 150 mm SKP placa Petri pipeta 75-100 l de cultivo saturado y extender uniformemente usando un esparcidor de vidrio estéril. Incubar las placas a 37 ° C durante 20-24 h. </li><li> Retire las placas de la incubadora y deje que se enfríen a temperatura ambiente (~ 20 min). Uso de tampón M9, lavar los gusanos de la etapa 1.4 en PA14 :: placas de GFP en un volumen mínimo de líquido. Al utilizar placas de 150 mm, varios cientos de gusanos se pueden colocar en una sola placa. </li><li> Incubar las placas a 25 ° C durante 18-21 horas. Para P. gusanos adultos jóvenes expuestos aeruginosa, esta es la ventana de tiempo que muestra la distribución óptima de los colonizados contra los animales no colonizados. </li></ol> 3. Configuración del Wormsorter Antes de realizar la muestra tipo, asegúrese de que la máquina está funcionando correctamente. Los detalles se pueden obtener en http://www.unionbio.com/support/documents.aspx?id=43, y thcorreos pasos esenciales se describen a continuación. <ol><li> Ajustar la presión de la válvula de la vaina de aproximadamente 5 psi (4.5 a 5.5 rango). </li><li> Para comprobar que la velocidad de flujo de fluido de funda es apropiado, coloque un tubo cónico de 15 ml debajo del dispensador, gire la válvula de la vaina, y cierre la válvula del clasificador. Sostenga el tubo debajo del dispensador durante 60 segundos. El volumen en el tubo debe ser de 9-10 ml. Si es fuera de este rango, ajuste la presión de la válvula vaina consecuencia. </li><li> Para garantizar que el caudal de fluido de funda (establecido como en el paso 3.2) permitirá la clasificación exacta, probar la velocidad de clasificación usando 40 partículas micras de control: </li><li> Cierre la válvula de la vaina. Añadir aproximadamente 25 ml de solución de partículas de control al depósito. </li><li> Abra la válvula de la vaina, y la válvula de muestra. </li><li> En el software de su ordenador, vaya a la &quot;partícula de modo de control&quot; y haga clic en Adquirir. </li><li> Asegúrese de que la velocidad de flujo de partículas es de ~ 5-8 partículas / seg, con un TOF (tiempo de vuelo) se aproxima a la anchurade la partícula, 40 micras. Tal TOF indica que sólo un único 40 micras objeto está pasando a través a la vez. Si los valores se encuentran fuera de este rango, ajuste la configuración (siguiendo las instrucciones anteriores) en consecuencia. </li></ol> 4. Ordenando Colonizada vs noncolonized Worms <ol><li> Uso de M9, lavar gusanos en tubos cónicos de 15 ml. Permitir gusanos adultos se hundan hasta el fondo del tubo por gravedad y eliminar el sobrenadante. Llene el tubo con frescos M9. Repita este proceso 3-4x. Esto elimina una gran proporción de larvas, así como el exceso de bacterias y tarda unos 10 min. </li><li> Añadir gusanos al depósito wormsorter con una pequeña barra de agitación suavemente-mezclado. </li><li> Ajuste la ganancia de la señal inicial estableciendo el PMT verde a 600 y el rojo y el amarillo PMT 200. </li><li> Comience la adquisición de datos para ajustar la configuración. </li><li> Trate de mantener un tipo de clase de 25 a 30 eventos (gusanos) por segundo. Si la tasa de número es demasiado alto, diluir los gusanos en el depósito con M9 en consecuencia. Si la tasa eso bajo, añada más gusanos en un pequeño volumen de M9. </li><li> Si el experimento requiere una separación muy estricta de colonizado vs gusanos no colonizados, establezca el &quot;control de coincidencia&quot; a &quot;puro&quot;. Esto asegura que en el caso de que dos objetos se producen demasiado cerca unos de otros o en la misma gota, la máquina rechaza la gota en lugar de recogerla. </li><li> Para clasificar la población de interés, dibujar puertas alrededor de los ejes que indican el tamaño (para obtener gusanos adultos) y la intensidad de fluorescencia (es decir, alto para colonizada, baja para no colonizada). Los valores de fluorescencia para inyección deben ser determinadas empíricamente. </li><li> Coloque una placa de múltiples pocillos o una placa de Petri debajo del dispensador para recoger gusanos a continuación, abra la válvula de tipo para comenzar a ordenar los gusanos. </li><li> Se recoge una pequeña población de animales para verificar al microscopio que la población ordenados es la población de interés. Si no es así, ajuste los parámetros de compuerta de acuerdo y continuar con la recogida de muestras. </li></ol>

<ol>
	<li>Pulak, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Techniques+for+analysis,+sorting,+and+dispensing+of+C.+elegans+on+the+COPAS+flow-sorting+system.">Techniques for analysis, sorting, and dispensing of C. elegans on the COPAS flow-sorting system.</a> Methods Mol. Biol. , 275-286 (2006).</li><li>Dupuy, 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=Genome-scale+analysis+of+in+vivo+spatiotemporal+promoteractivity+in+Caenorhabditis+elegans.">Genome-scale analysis of in vivo spatiotemporal promoteractivity in Caenorhabditis elegans.</a> Nat. Biotechnol. 25, 663-668 (2007).</li><li>Squiban, B., Belougne, J., Ewbank, J., Zugasti, O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Quantitative+and+Automated+High-throughput+Genome-wide+RNAi+Screens+in+elegans.">Quantitative and Automated High-throughput Genome-wide RNAi Screens in elegans.</a> J. Vis. Exp. (60), (2012).</li><li>Doitsidou, M., Flames, N., Lee, A. C., Boyanov, A., Hobert, O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Automated+screening+for+mutants+affecting+dopaminergic-neuron+specification+in+C.+elegans.">Automated screening for mutants affecting dopaminergic-neuron specification in C. elegans.</a> Nat. Methods. 5, 869-872 (2008).</li><li>Pujol, N., 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=Distinct+innate+immune+responses+to+infection+and+wounding+in+the+C.+elegans+epidermis.">Distinct innate immune responses to infection and wounding in the C. elegans epidermis.</a> Curr. Biol. 18, 481-489 (2008).</li><li>Medzhitov, R., Janeway, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Innate+immune+recognition:+mechanisms+and+pathways.">Innate immune recognition: mechanisms and pathways.</a> Immunol. Rev. 173, 89-97 (2000).</li><li>Matzinger, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tolerance,+danger,+and+the+extended+family.">Tolerance, danger, and the extended family.</a> Annu. Rev. Immunol. 12, 991-1045 (1994).</li><li>Mariathasan, S., 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=Cryopyrin+activates+the+inflammasome+in+response+to+toxins+and+ATP.">Cryopyrin activates the inflammasome in response to toxins and ATP.</a> Nature. 440, 228-232 (2006).</li><li>Melo, J. A., Ruvkun, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Inactivation+of+conserved+C.+elegans+genes+engages+pathogen-+and+xenobiotic-associated+defenses.">Inactivation of conserved C. elegans genes engages pathogen- and xenobiotic-associated defenses.</a> Cell. 149, 452-466 (2012).</li><li>Chen, G. Y., Nunez, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sterile+inflammation:+sensing+and+reacting+to+damage.">Sterile inflammation: sensing and reacting to damage.</a> Nat. Rev. Immunol. 10, 826-837 (2010).</li><li>Tenor, J. L., Aballay, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+conserved+Toll-like+receptor+is+required+for+Caenorhabditis+elegans+innate+immunity.">A conserved Toll-like receptor is required for Caenorhabditis elegans innate immunity.</a> EMBO Rep. 9, 103-109 (2008).</li><li>Pujol, N., 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+reverse+genetic+analysis+of+components+of+the+Toll+signaling+pathway+in+Caenorhabditis+elegans.">A reverse genetic analysis of components of the Toll signaling pathway in Caenorhabditis elegans.</a> Curr. Biol. 11, 809-821 (2001).</li><li>McEwan, D. L., Kirienko, N. V., Ausubel, F. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Host+translational+inhibition+by+Pseudomonas+aeruginosa+Exotoxin+A+Triggers+an+immune+response+in+Caenorhabditis+elegans.">Host translational inhibition by Pseudomonas aeruginosa Exotoxin A Triggers an immune response in Caenorhabditis elegans.</a> Cell Host Microbe. 11, 364-374 (2012).</li><li>Dunbar, T. L., Yan, Z., Balla, K. M., Smelkinson, M. G., Troemel, E. R. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=C.+elegans+detects+pathogen-induced+translational+inhibition+to+activate+immune+signaling.">C. elegans detects pathogen-induced translational inhibition to activate immune signaling.</a> Cell Host Microbe. 11, 375-386 (2012).</li><li>Irazoqui, J. 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=Distinct+pathogenesis+and+host+responses+during+infection+of+C.+elegans+by+P.+aeruginosa+and+S.+aureus.">Distinct pathogenesis and host responses during infection of C. elegans by P. aeruginosa and S. aureus.</a> PLoS Pathog. 6, (2010).</li><li>Pukkila-Worley, R., Ausubel, F. M., Mylonakis, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Candida+albicans+infection+of+Caenorhabditis+elegans+induces+antifungal+immune+defenses.">Candida albicans infection of Caenorhabditis elegans induces antifungal immune defenses.</a> PLoS Pathog. , (2011).</li><li>Shapira, 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=A+conserved+role+for+a+GATA+transcription+factor+in+regulating+epithelial+innate+immune+responses.">A conserved role for a GATA transcription factor in regulating epithelial innate immune responses.</a> Proc. Natl. Acad. Sci. U.S.A. 103, 14086-14091 (2006).</li><li>Troemel, E. R., 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=p38+MAPK+regulates+expression+of+immune+response+genes+and+contributes+to+longevity+in+C.+elegans.">p38 MAPK regulates expression of immune response genes and contributes to longevity in C. elegans.</a> PLoS Genet. , 183 (2006).</li><li>Twumasi-Boateng, K., Shapira, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dissociation+of+immune+responses+from+pathogen+colonization+supports+pattern+recognition+in+C.+elegans.">Dissociation of immune responses from pathogen colonization supports pattern recognition in C. elegans.</a> PLoS One. , 7 (2012).</li><li>Jakobsen, H., 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=The+alkaloid+compound+harmane+increases+the+lifespan+of+Caenorhabditis+elegans+during+bacterial+infection,+by+modulating+the+nematode's+innate+immune+response.">The alkaloid compound harmane increases the lifespan of Caenorhabditis elegans during bacterial infection, by modulating the nematode's innate immune response.</a> PLoS One. 8, (2013).</li><li>Portal-Celhay, C., Bradley, E. R., Blaser, M. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Control+of+intestinal+bacterial+proliferation+in+regulation+of+lifespan+in+Caenorhabditis+elegans.">Control of intestinal bacterial proliferation in regulation of lifespan in Caenorhabditis elegans.</a> BMC Microbiol. 12, 49 (2012).</li><li>Troemel, E. R., Felix, M. A., Whiteman, N. K., Barriere, A., Ausubel, F. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microsporidia+are+natural+intracellular+parasites+of+the+nematode+Caenorhabditis+elegans.">Microsporidia are natural intracellular parasites of the nematode Caenorhabditis elegans.</a> PLoS Biol. 6, 2736-2752 (2008).</li><li>Montalvo-Katz, S., Huang, H., Appel, M. D., Berg, M., Shapira, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Association+with+soil+bacteria+enhances+p38-dependent+infection+resistance+in+Caenorhabditis+elegans.">Association with soil bacteria enhances p38-dependent infection resistance in Caenorhabditis elegans.</a> Infect. Immun. 18, 514-520 (2013).</li></ol>

The authors have nothing to disclose.

The method we describe takes advantage of fluorescent labeling of entities outside of the worm, to follow interactions between the worm and its environment. In the case we present, separation was based on labeling of a pathogen and was employed to separate worms with heavy pathogen load from those with no (or light) load. Subsequent gene expression analysis found no difference in immune responses between the two groups suggesting that they were independent of pathogen load. The signal that initiates the response was show...

Clasificación automática gusano es muy similar a FACS, operando mediante la medición de una señal fluorescente en un tornillo sin fin (normalmente proporcionado por la expresión transgénica de las proteínas informadoras) a medida que pasa enderezó en un tubo, lo que permite la redirección ya sea a un tubo de recogida / o bien a un contenedor de residuos de acuerdo para conmutar parámetros establecidos por el investigador 1. El wormsorter puede facilitar la investigación de muchas maneras, un ejemplo de emplearlo como herramienta de análisis es un estudio que siguió los patrones espacio-temporales de la actividad promotora de casi 1.000 genes 2. Sin embargo, el uso principal de la wormsorter es en pantallas genéticos, siguiente objetivo los niveles de expresión de genes o localización de la proteína fluorescente a lo largo del eje del gusano 3-5. Aquí se describe una nueva aplicación para el wormsorter, en el seguimiento de la colonización del gusano por un patógeno marcado con fluorescencia. Con esto como una herramienta que se centró en la relación entre Pathogen la colonización / carga y la respuesta inmune, para obtener nuevos conocimientos sobre los mecanismos responsables de la iniciación de la respuesta inmune en el gusano. En casi todos los organismos estudiados hasta la fecha, la iniciación de la respuesta inmune innata a patógenos microbianos depende del reconocimiento de patrones moleculares asociados a patógenos (PAMP), y / o peligro / daño-patrones moleculares asociados (amortigua) 6,7. Las estructuras microbianas primero se conservan que incluyen componentes de la pared celular microbiana, su flagelo, o su bicapa lipídica 6; el segundo, incluyen tanto moléculas liberadas (por ejemplo ATP 8), proteínas alteradas u otros marcadores de los procesos celulares alterados 9,10. Ambos tipos de señales son reconocidas por proteínas designadas como receptores de reconocimiento de patrones (RRP), que tras la unión específica de una molécula patrón activar una cadena de eventos que conducen a una respuesta protectora. C. elegans ha sido extremadamente útil como tractamodelo ble para diseccionar los diversos aspectos de las interacciones huésped-patógeno, pero una cosa que no es bien entendido es cómo se inician la respuesta inmune en el gusano. Ninguno de los supuestos receptores que son ortólogos a los receptores de reconocimiento de patrones (PRRS) en otros organismos se ha demostrado que se unen PAMP, y muchos de los ortólogos de PRRS que son fundamentales para la respuesta inmune en otros organismos mostrar una contribución sorprendentemente limitado a las respuestas de patógenos gusano y la resistencia. Por ejemplo, el receptor Toll de Drosophila, que es esencial para resistir los patógenos Gram positivos, se representa en C. elegans por un único homólogo, Tol-1, lo que contribuye a la protección contra el patógeno Gram negativa Salmonella typhimurium 11, pero no de otros patógenos Gram-negativas, o-positivos 11,12 probados. Estas observaciones, junto con datos que indican que las respuestas inmunes podría ser inducido mediante la interrupción de la proteína celular traducción hcomo llevado a algunos a sugerir que C. elegans detecta principalmente DAMPS 9,13,14. Sin embargo, informes que describen la capacidad de los patógenos muertos para inducir respuestas inmunes sugerir que PAMP de unión puede ser tiene un papel importante en el reconocimiento de patógenos en C. elegans 15,16. El trabajo previo se centra en la respuesta inmune en sincronizada edad genéticamente idénticos C. elegans poblaciones, demostraron una gran variabilidad individual en la colonización intestinal por el Gram-negative bacteria patógena Pseudomonas aeruginosa. Sin embargo, los estudios de perfiles transcripcionales tratan estas poblaciones colonizadas de forma variable-como una entidad 17,18. Tomando ventaja de esta variabilidad, se desarrolló un protocolo de enfocar una wormsorter automatizado para separar las poblaciones colonizadas de forma diferencial Caenorhabditis elegans expuestos a GFP-expresando P. aeruginosa. El examen de la expresión de genes en las poblaciones colonizadas de forma diferente-Facilitated evaluación de la relación entre la carga de patógenos (y el daño asociado) y las respuestas inmunes y proporcionado nuevas perspectivas sobre el reconocimiento de patógenos en C. elegans 19. A continuación se describe el protocolo, que podría ser aplicado para ordenar los gusanos infectados por el patógeno cualquier etiqueta fluorescente. Para los usuarios potenciales cabe señalar que el número de gusanos requeridos para ser resuelto depende de la naturaleza de los análisis posteriores y protocolos en uso. Por ejemplo, en el caso de análisis de microarrays de expresión génica,&gt; se requerirán 1000 gusanos para obtener suficiente ARN, si se utilizan protocolos estándar, pero ~ 100 gusanos sería suficiente si se emplea la amplificación, permitiendo colección rápido de material y minimizando así el estrés a los gusanos.

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		<col />
	</colgroup>
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:261px;">M9 Buffer</td>
			<td style="width:139px;">Prepared in house</td>
			<td style="width:527px;">Recipe at wormbook.org</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Rifampicin&#160;</td>
			<td>Sigma</td>
			<td>R3501</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Egg prep solution&#160;</td>
			<td>Prepared in house</td>
			<td>50ml water ; 40ml bleach ; 10ml of 10N Sodium Hydroxide&#160;</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">NGM plates&#160;</td>
			<td>Prepared in house</td>
			<td>Recipe at wormbook.org</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">SKP plates</td>
			<td>Prepared in house</td>
			<td>Recipe same as NGM only 0.35% peptone instead of 0.25%</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Control test particles&#160;</td>
			<td>Union Biometrica&#160;</td>
			<td>310-5071-001</td>
		</tr>
	</tbody>
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automated separation of c. elegans variably colonized by a bacterial pathogen

El wormsorter es un instrumento similar a una máquina de FACS que se utiliza en los estudios de Caenorhabditis elegans, típicamente para ordenar gusanos basados ​​en la expresión de un indicador fluorescente. Aquí, destacamos un uso alternativo de este instrumento, para la clasificación de los gusanos de acuerdo a su grado de colonización por parte de un agente patógeno que expresa GFP. Este nuevo uso nos permitió abordar la relación entre la colonización del intestino del gusano y la inducción de la respuesta inmune. Mientras C. las respuestas inmunes frente a diferentes patógenos elegans se han documentado, todavía no se sabe lo que los inicia. Las dos posibilidades principales (que no son mutuamente excluyentes) son el reconocimiento de patrones moleculares asociados a patógenos, y la detección de los daños causados ​​por la infección. Para diferenciar entre las dos posibilidades, la exposición al patógeno debe disociarse del daño que causa. El wormsorter permitido la separación de los gusanos que fueron colonizados extensamente por el Gram-npatógeno egative Pseudomonas aeruginosa, con el probable daño causado por la carga de patógenos, de los gusanos que fueron expuestos de manera similar, pero no es así, o marginalmente, colonizado. Se utilizaron estas poblaciones distintas para evaluar la relación entre la carga de patógenos y la inducción de respuestas inmunes de la transcripción. Los resultados sugieren que los dos se disocian, el apoyo a la posibilidad de reconocimiento de patógenos.

Cuando se combina la edad, genéticamente idénticos C. elegans están expuestos a P. aeruginosa, una amplia distribución se observa en los niveles de colonización (Figura 1A). Con la ayuda del protocolo descrito aquí separación eficiente de no colonizada de gusanos colonizados se puede lograr (Figura 1B). A diferencia de los gusanos no colonizados, gusanos colonizados muestran signos de daño, tales como la lentitud y la reducción de la defecación al aire 1...

Watch this Scientific Journal Video about Automated Separation of C. elegans Variably Colonized by a Bacterial Pathogen at JoVE.com

Automated Separation of C. elegans Variably Colonized by a Bacterial Pathogen

El wormsorter facilita pantallas genéticas en Caenorhabditis elegans clasificando gusanos de acuerdo a la expresión de los reporteros fluorescentes. Aquí se describe un nuevo uso: la clasificación de acuerdo a la colonización por un patógeno que expresa GFP, y lo empleamos para examinar el papel poco conocido de reconocimiento de patógenos en la iniciación de la respuesta inmune.

La separación automatizada de<em&gt; C. elegans</em&gt; Variablemente colonizada por un patógeno bacteriano

The wormsorter is an instrument analogous to a FACS machine that is used in studies of Caenorhabditis elegans, typically to sort worms based on expression ...

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JoVE Journal

Immunology and Infection

Automated Separation of C. elegans Variably Colonized by a Bacterial Pathogen

8.3K vistas.  University of California, Berkeley.  El wormsorter facilita pantallas genéticas en Caenorhabditis elegans clasificando gusanos de acuerdo a la expresión de los reporteros fluorescentes. Aquí se describe un nuevo uso: la clasificación de acuerdo a la colonización por un patógeno que expresa GFP, y lo empleamos para examinar el papel poco conocido de reconocimiento de patógenos en la iniciación de la respuesta inmune. 

Video: Automated Separation of C. elegans Variably Colonized by a Bacterial Pathogen

Assay for Pathogen-Associated Molecular Pattern (PAMP)-Triggered Immunity (PTI) in Plants

To perceive potential pathogens in their environment, plants use pattern recognition receptors (PRRs) present on their plasma membranes. PRRs recognize conserved microbial features called pathogen-associated molecular patterns (PAMPs) and this detection leads to PAMP-triggered immunity (PTI), which effectively prevents colonization of plant tissues by non-pathogens1,2. The most well studied system in PTI is the FLS2-dependent pathway3. FLS2 recognizes the PAMP flg22 that is a component of bacterial flagellin. 
Successful pathogens possess virulence factors or effectors that can suppress PTI and allow the pathogen to cause disease1. Some plants in turn possess resistance genes that detect effectors or their activity, which leads to effector-triggered immunity (ETI)2.
We describe a cell death-based assay for PTI modified from Oh and Collmer4. The assay was standardized in N. benthamiana, which is being used increasingly as a model system for the study of plant-pathogen interactions5. PTI is induced by infiltration of a non-pathogenic bacterial strain into leaves. Seven hours later, a bacterial strain that either causes disease or which activates ETI is infiltrated into an area overlapping the original infiltration zone. PTI induced by the first infiltration is able to delay or prevent the appearance of cell death due to the second challenge infiltration. Conversely, the appearance of cell death in the overlapping area of inoculation indicates a breakdown of PTI. 
Four different combinations of inducers of PTI and challenge inoculations were standardized (Table 1). The assay was tested on non-silenced N. benthamiana plants that served as the control and plants silenced for FLS2 that were predicted to be compromised in their ability to develop PTI.

Assay for Pathogen-Associated Molecular Pattern PAMP-Triggered Immunity PTI in Plants

A cell death-based assay for PTI in Nicotiana benthamiana plants is described.

Ensayo para asociados a patógenos patrón molecular (PAMP)-Accionados Inmunidad (PTI) en las plantas

To perceive potential pathogens in their environment, plants use pattern recognition receptors (PRRs) present on their plasma membranes. PRRs recognize ...

Investigación

Inmunología e Infección

Invasion of Human Cells by a Bacterial Pathogen

Here we will describe how we study the invasion of human endothelial cells by bacterial pathogen Staphylococcus aureus . The general protocol can be applied to the study of cell invasion by virtually any culturable bacterium. The stages at which specific aspects of invasion can be studied, such as the role of actin rearrangement or caveolae, will be highlighted. Host cells are grown in flasks and when ready for use are seeded into 24-well plates containing Thermanox coverslips. Using coverslips allows subsequent removal of the cells from the wells to reduce interference from serum proteins deposited onto the sides of the wells (to which S. aureus would attach). Bacteria are grown to the required density and washed to remove any secreted proteins (e.g. toxins). Coverslips with confluent layers of endothelial cells are transferred to new 24-well plates containing fresh culture medium before the addition of bacteria. Bacteria and cells are then incubated together for the required amount of time in 5% CO2 at 37&deg;C. For S. aureus this is typically between 15-90 minutes. Thermanox coverslips are removed from each well and dip-washed in PBS to remove unattached bacteria. If total associated bacteria (adherent and internalised) are to be quantified, coverslips are then placed in a fresh well containing 0.5% Triton X-100 in PBS. Gentle pipetting leads to complete cell lysis and bacteria are enumerated by serial dilution and plating onto agar. If the number of bacteria that have invaded the cells is needed, coverslips are added to wells containing 500 &mu;l tissue culture medium supplemented with gentamicin and incubation continued for 1 h, which will kill all external bacteria. Coverslips can then be washed, cells lysed and bacteria enumerated by plating onto agar as described above. If the experiment requires direct visualisation, coverslips can be fixed and stained for light, fluorescence or confocal microscopy or prepared for electron microscopy.

A general protocol for the study of invasion of host cells by a bacterial pathogen, focusing on Staphylococcus aureus and human endothelial cells.

La invasión de las células humanas por un patógeno bacteriano

Here we will describe how we study the invasion of human endothelial cells by bacterial pathogen Staphylococcus aureus . The general protocol can be ...

Saliva, Salivary Gland, and Hemolymph Collection from Ixodes scapularis Ticks

Ticks are found worldwide and afflict humans with many tick-borne illnesses. Ticks are vectors for pathogens that cause Lyme disease and tick-borne relapsing fever (Borrelia spp.), Rocky Mountain Spotted fever (Rickettsia rickettsii), ehrlichiosis (Ehrlichia chaffeensis and E. equi), anaplasmosis (Anaplasma phagocytophilum), encephalitis (tick-borne encephalitis virus), babesiosis (Babesia spp.), Colorado tick fever (Coltivirus), and tularemia (Francisella tularensis) 1-8. To be properly transmitted into the host these infectious agents differentially regulate gene expression, interact with tick proteins, and migrate through the tick 3,9-13. For example, the Lyme disease agent, Borrelia burgdorferi, adapts through differential gene expression to the feast and famine stages of the tick's enzootic cycle 14,15. Furthermore, as an Ixodes tick consumes a bloodmeal Borrelia replicate and migrate from the midgut into the hemocoel, where they travel to the salivary glands and are transmitted into the host with the expelled saliva 9,16-19.
As a tick feeds the host typically responds with a strong hemostatic and innate immune response 11,13,20-22. Despite these host responses, I. scapularis can feed for several days because tick saliva contains proteins that are immunomodulatory, lytic agents, anticoagulants, and fibrinolysins to aid the tick feeding 3,11,20,21,23. The immunomodulatory activities possessed by tick saliva or salivary gland extract (SGE) facilitate transmission, proliferation, and dissemination of numerous tick-borne pathogens 3,20,24-27. To further understand how tick-borne infectious agents cause disease it is essential to dissect actively feeding ticks and collect tick saliva. This video protocol demonstrates dissection techniques for the collection of hemolymph and the removal of salivary glands from actively feeding I. scapularis nymphs after 48 and 72 hours post mouse placement. We also demonstrate saliva collection from an adult female I. scapularis tick.

Saliva, Salivary Gland, and Hemolymph Collection from Ixodes scapularis Ticks

The collection of infected tick hemolymph, salivary glands, and saliva is important to study how tick-borne pathogens cause disease. In this protocol we demonstrate how to collect hemolymph and salivary glands from feeding Ixodes scapularis nymphs. We also demonstrate saliva collection from female I. scapularis adults.

La saliva, la glándula salival, y la Colección hemolinfa de las garrapatas Ixodes scapularis

Ticks are found worldwide and afflict humans with many tick-borne illnesses. Ticks are vectors for pathogens that cause Lyme disease and tick-borne ...

Visualization of Bacterial Toxin Induced Responses Using Live Cell Fluorescence Microscopy

Bacterial toxins bind to cholesterol in membranes, forming pores that allow for leakage of cellular contents and influx of materials from the external environment. The cell can either recover from this insult, which requires active membrane repair processes, or else die depending on the amount of toxin exposure and cell type1. In addition, these toxins induce strong inflammatory responses in infected hosts through activation of immune cells, including macrophages, which produce an array of pro-inflammatory cytokines2. Many Gram positive bacteria produce cholesterol binding toxins which have been shown to contribute to their virulence through largely uncharacterized mechanisms.
Morphologic changes in the plasma membrane of cells exposed to these toxins include their sequestration into cholesterol-enriched surface protrusions, which can be shed into the extracellular space, suggesting an intrinsic cellular defense mechanism3,4. This process occurs on all cells in the absence of metabolic activity, and can be visualized using EM after chemical fixation4. In immune cells such as macrophages that mediate inflammation in response to toxin exposure, induced membrane vesicles are suggested to contain cytokines of the IL-1 family and may be responsible both for shedding toxin and disseminating these pro-inflammatory cytokines5,6,7. A link between IL-1&beta; release and a specific type of cell death, termed pyroptosis has been suggested, as both are caspase-1 dependent processes8. To sort out the complexities of this macrophage response, which includes toxin binding, shedding of membrane vesicles, cytokine release, and potentially cell death, we have developed labeling techniques and fluorescence microscopy methods that allow for real time visualization of toxin-cell interactions, including measurements of dysfunction and death (Figure 1). Use of live cell imaging is necessary due to limitations in other techniques. Biochemical approaches cannot resolve effects occurring in individual cells, while flow cytometry does not offer high resolution, real-time visualization of individual cells. The methods described here can be applied to kinetic analysis of responses induced by other stimuli involving complex phenotypic changes in cells.

Methods for purifying the cholesterol binding toxin streptolysin O from recombinant E. coli and visualization of toxin binding to live eukaryotic cells are described. Localized delivery of toxin induces rapid and complex changes in targeted cells revealing novel aspects of toxin biology.

La visualización de las respuestas inducidas por toxinas bacterianas mediante microscopía de fluorescencia de células en vivo

Bacterial toxins bind to cholesterol in membranes, forming pores that allow for leakage of cellular contents and influx of materials from the external ...

Imaging InlC Secretion to Investigate Cellular Infection by the Bacterial Pathogen Listeria monocytogenes

Bacterial intracellular pathogens can be conceived as molecular tools to dissect cellular signaling cascades due to their capacity to exquisitely manipulate and subvert cell functions which are required for the infection of host target tissues. Among these bacterial pathogens, Listeria monocytogenes is a Gram positive microorganism that has been used as a paradigm for intracellular parasitism in the characterization of cellular immune responses, and which has played instrumental roles in the discovery of molecular pathways controlling cytoskeletal and membrane trafficking dynamics. In this article, we describe a robust microscopical assay for the detection of late cellular infection stages of L. monocytogenes based on the fluorescent labeling of InlC, a secreted bacterial protein which accumulates in the cytoplasm of infected cells; this assay can be coupled to automated high-throughput small interfering RNA screens in order to characterize cellular signaling pathways involved in the up- or down-regulation of infection.

Imaging InlC Secretion to Investigate Cellular Infection by the Bacterial Pathogen Listeria monocytogenes

Listeria monocytogenes is a Gram positive bacterial pathogen frequently used as a major model for the study of intracellular parasitism. Imaging late L. monocytogenes infection stages within the context of small-interfering RNA screens allows for the global study of cellular pathways required for bacterial infection of target host cells.

Imaging InlC secreción de investigar la infección celular por el patógeno bacteriano<em&gt; Listeria monocytogenes</em

Bacterial intracellular  pathogens can be conceived as molecular tools to dissect cellular signaling  cascades due to their capacity to exquisitely ...

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.

Generación y multi-fenotípicos cribado de alto contenido de<em&gt; Coxiella burnetii</em&gt; transposón mutantes

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

Unravelling the Function of a Bacterial Effector from a Non-cultivable Plant Pathogen Using a Yeast Two-hybrid Screen

Unravelling the molecular mechanisms of disease manifestations is important to understand pathologies and symptom development in plant science. Bacteria have evolved different strategies to manipulate their host metabolism for their own benefit. This bacterial manipulation is often coupled with severe symptom development or the death of the affected plants. Determining the specific bacterial molecules responsible for the host manipulation has become an important field in microbiological research. After the identification of these bacterial molecules, called &#34;effectors,&#34; it is important to elucidate their function. A straightforward approach to determine the function of an effector is to identify its proteinaceous binding partner in its natural host via a yeast two-hybrid (Y2H) screen. Normally the host harbors numerous potential binding partners that cannot be predicted sufficiently by any in silico algorithm. It is thus the best choice to perform a screen with the hypothetical effector against a whole library of expressed host proteins. It is especially challenging if the causative agent is uncultivable like phytoplasma. This protocol provides step-by-step instructions for DNA purification from a phytoplasma-infected woody host plant, the amplification of the potential effector, and the subsequent identification of the plant&#39;s molecular interaction partner with a Y2H screen. Even though Y2H screens are commonly used, there is a trend to outsource this technique to biotech companies that offer the Y2H service at a cost. This protocol provides instructions on how to perform a Y2H in any decently equipped molecular biology laboratory using standard lab techniques.

Bacterial effector proteins are important for establishing successful infections. This protocol describes the experimental identification of proteinaceous binding partners of a bacterial effector protein in its natural plant host. Identifying these effector interactions via yeast two-hybrid screens has become an important tool in unravelling molecular pathogenicity strategies.

Desenredar la función de un efector bacteriana de una planta de patógenos no cultivables Uso de una levadura de dos híbridos pantalla

Unravelling the molecular mechanisms of disease manifestations is important to understand pathologies and symptom development in plant science. Bacteria ...

Enrichment of Bacterial Lipoproteins and Preparation of N-terminal Lipopeptides for Structural Determination by Mass Spectrometry

Lipoproteins are important constituents of the bacterial cell envelope and potent activators of the mammalian innate immune response. Despite their significance to both cell physiology and immunology, much remains to be discovered about novel lipoprotein forms, how they are synthesized, and the effect of the various forms on host immunity. To enable thorough studies on lipoproteins, this protocol describes a method for bacterial lipoprotein enrichment and preparation of N-terminal tryptic lipopeptides for structural determination by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS). Expanding on an established Triton X-114 phase partitioning method for lipoprotein extraction and enrichment from the bacterial cell membrane, the protocol includes additional steps to remove non-lipoprotein contaminants, increasing lipoprotein yield and purity. Since lipoproteins are commonly used in Toll-like receptor (TLR) assays, it is critical to first characterize the N-terminal structure by MALDI-TOF MS. Herein, a method is presented to isolate concentrated hydrophobic peptides enriched in N-terminal lipopeptides suitable for direct analysis by MALDI-TOF MS/MS. Lipoproteins that have been separated by Sodium Dodecyl Sulfate Poly-Acrylamide Gel Electrophoresis (SDS-PAGE) are transferred to a nitrocellulose membrane, digested in situ with trypsin, sequentially washed to remove polar tryptic peptides, and finally eluted with chloroform-methanol. When coupled with MS of the more polar trypsinized peptides from wash solutions, this method provides the ability to both identify the lipoprotein and characterize its N-terminus in a single experiment. Intentional sodium adduct formation can also be employed as a tool to promote more structurally informative fragmentation spectra. Ultimately, enrichment of lipoproteins and determination of their N-terminal structures will permit more extensive studies on this ubiquitous class of bacterial proteins.

The enrichment of bacterial lipoproteins using a non-ionic surfactant phase partitioning method is described for direct use in TLR assays or other applications. Further steps are detailed to prepare N-terminal tryptic lipopeptides for structural characterization by mass spectrometry.

Enriquecimiento de lipoproteínas bacterianas y preparación de lipopéptidos N-terminal para la determinación estructural por espectrometría de masas

Lipoproteins are important constituents of the bacterial cell envelope and potent activators of the mammalian innate immune response. Despite their ...

A High-throughput, High-content, Liquid-based C. elegans Pathosystem

The number of new drugs identified by traditional, in vitro screens has waned, reducing the success of this approach in the search for new weapons to combat multiple drug resistance. This has led to the conclusion that researchers do not only need to find new drugs, but also need to develop new ways of finding them. Amongst the most promising candidate methods are whole-organism, in vivo assays that use high-throughput, phenotypic readouts and hosts that range from Caenorhabditis elegans to Danio rerio. These hosts have several powerful advantages, including dramatic reductions in false positive hits, as compounds that are toxic to the host and/or biounavailable are typically dropped in the initial screen, prior to costly follow up.
Here we show how our assay has been used to interrogate host variation in the well-documented C. elegans&#8212;Pseudomonas aeruginosa liquid killing pathosystem. We also demonstrate several extensions of this well-worked out technique. For example, we are able to carry out high-throughput genetic screens using RNAi in 24- or 96-well plate formats to query host factors in this host-pathogen interaction. Using this assay, whole genome screens can be completed in only a few months, which can dramatically simplify the task of identifying drug targets, potentially without the need for laborious biochemical purification approaches.
We also report here a variation of our method that substitutes the gram-positive bacterium Enterococcus faecalis for the gram-negative pathogen P. aeruginosa. Much as is the case for P. aeruginosa, killing by E. faecalis is time-dependent. Unlike previous C. elegans&#8212;E. faecalis assays, our assay for E. faecalis does not require preinfection, improving its safety profile and reducing the chances of contaminating liquid-handling equipment. The assay is highly robust, showing ~95% death rates 96 h post infection.

A High-throughput, High-content, Liquid-based C. elegans Pathosystem

Here we describe a protocol that is an adaptable, whole host, high-content screening tool that can be utilized to study host-pathogen interactions and be used for drug discovery.

Un alto rendimiento, alto contenido líquido y basada en C. elegans patosistema

The number of new drugs identified by traditional, in vitro screens has waned, reducing the success of this approach in the search for new weapons to ...

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.

Análisis conductual de gran C. elegans las poblaciones utilizando un amplio campo de visión de seguimiento plataforma automatizada

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