This project was supported by Midwestern University, IL Office of Research and Sponsored Programs (ORSP) and Midwestern University College of Dental Medicine-Illinois (CDMI).

1. HSV Cepas y Manipulación Nota: Recombinante la no propagación de HSV-1 (KOS) gL86 y HSV-2 (KOS) 333gJ - con el reportero de la actividad de beta-galactosidasa utilizado fueron proporcionados por V. Twiari 36,37. <ol><li> Utilice virus de un solo lote y se almacena a -80 ° C, a una proporción de 1: 1 de medio de Eagle modificado por Dulbecco (DMEM) con suero bovino fetal al 20% (FBS) y leche descremada hasta su uso. Antes del almacenamiento mucho viral, determinar la concentración de virus por o-nitrofenil-β-D-galactopiranósido (ONPG) y 5-bromo-4-cloro-3-indolil-β-D-galactopiranósido (X-Gal) ensayo. </li><li> Determinar la viabilidad del virus y la multiplicidad de infección (MOI) por tinción con X-Gal para cada ensayo experimental usando el ensayo de la entrada del virus reportero, tal como se describe anteriormente (figura 1) 14. </li><li> Diluir el virus (Opt-MEM) para MOI deseada. Fijar monocapas (paraformaldehído; 0,5 ml / pocillo) antes de la tinción. Coloque los controles de la viabilidad del virus en un microti separadater placa en paralelo con placas de ensayo polimicrobiana. </li></ol> Manejo células HeLa 2. 299 <ol><li> Crecer a 37 ° C, 5% de CO 2 en DMEM con 4,5 g / l de glucosa, 10% inactivado por calor suero fetal bovino (FBS), gentamicina (50 mg / ml) y L-glutamina. células de paso a 80% de confluencia con una solución de tripsina (ácido etilendiaminotetraacético, EDTA 0,53 M; 0,05% de tripsina; 5 ml / frasco). </li></ol> 3. C. Manipulación albicans Nota: C. albicans obtenidos a partir de una fuente de laboratorio clínico se almacena a -80 ° C en Remmel leche descremada 2x medio. <ol><li> Cultura congelado Stock en Sabouraud Dextrosa Medio (37 ° C). Después de 24 horas la subcultura C. albicans sobre medio Fungisel (37 ° C; 48 hr) para su uso. </li><li> Generar tubo germinal (GT) (formas recoger colonias representativas, 3 ml de FBS; 3 h; 37 ° C; Abs 600, 0,3). Después de la incubación, lavar GT (HBSS; 2x; 4.000 xg). Añadir GT lavado para HBSS calentado (37 y# 176; C; 0,32 Abs 600). formas GT debería ser el 99% de las células observadas según lo determinado por conteo de hemocitómetro. </li><li> Hacer suspensiones forma de levadura (FA) de acciones por recoger colonias representativas Fungisel (HBSS, 3 ml; 0,32 Abs 600). Contar el número de formas de YF / ml al microscopio utilizando un hemocitómetro. formas de fiebre amarilla deben ser del 99% de las células observadas según lo determinado por conteo de hemocitómetro. </li><li> Hacer trabajo stock fúngica (250 l de GT o YF social en 25 ml de HBSS; 37 ° C; 10 5 UFC / ml) </li></ol> 4. S. Manipulación aureus <ol><li> Tienda S. aureus ATCC 25923 (-80 ° C; Remmel descremada leche 2x). Cultura en agar sangre de carnero (5%; 37 ° C; 24 h). Recoger colonias y traslado al manitol sales de medio plazo de 2 días para la acción (37 ° C; 18 h). </li><li> Hacer S. aureus suspensión de acciones (3 ml de HBSS; 1,32 Abs 600; 10 8 UFC / ml) <ol><li> Hacer trabajar S. aureus acciones (100 lde las acciones en 25 ml de HBSS; 10 5 CFU / ml). </li></ol></li></ol> 5. Candida y S. aureus Suspensiones <ol><li> Hacer mixta C. albicans y S. suspensión aureus (250 YF l o GT de valores y 100 l de S. aureus de valores en 25 ml de HBSS). </li></ol> 6. Ensayo polimicrobiana Biofilm <ol><li> Y placas de semillas 96 con 200 l de 2 x 10 5 HeLa células / ml (85% de nivel de confluencia). Placas de roca (30 - 45 min; 37 ° C) antes de la incubación (37 ° C; 5% de CO2; 18 h). Lavar las monocapas (1x; Opt-MEM) a continuación de la semilla con el HSV (HSV-1 (KOS) gL86 o HSV-2 (KOS) 33 GJ - en 100 l Opt-MEM; MOI 50 y 10). Incubar las placas (3 hr; 37 ° C; 5% de CO 2). Utilice sólo una cepa viral por día. </li><li> Lavar monocapas infectadas (1x; salina tamponada con fosfato (PBS) con Mg 2 y Ca 2; 100 l). Reemplazar PBS con HBSS caliente dejando 25 &amp; #181; l en cada pocillo. <ol><li> Añadir YF, GT y / o S. aureus suspensiones de trabajo (100 l; diana a células ratio = 5: 1; n = 16). tal como se indica en la Tabla 1 (Incubar las placas estáticas; 30 min; 37 ° C; 5% de CO 2). </li></ol></li><li> Después de la incubación, aspirar una columna en un momento inmediatamente rellenado con 300 l de PBS con Mg + 2 y Ca + 2. Repita este paso dos veces y luego añadir tampón de lisis de ensayo de radio-inmunoprecipitación (RIPA, filtro esterilizado; 200 l de una dilución 1:50). </li><li> Rápidamente Se tritura el lisado de células HeLa a continuación, colocar 50 l en sales de manitol (MS) y medios de comunicación / o Fungisel (F) (Figura 2). Extender el lisado utilizando una varilla de vidrio doblado en un ángulo de 90 °. Se incuban las placas (18 horas a 37 ° C). contar manualmente el número de colonias por placa. Los controles consisten de S. aureus y / o C. albicans adherencia a las células HeLa no infectadas por VHS. </li></ol> 7. Estudios de Imagen &lt;/ P&gt; <ol><li> Lavar cada cubreobjetos circular de vidrio (12 mm; 50 ml de acetona en 100 ml vaso de precipitados). cubreobjetos secos y esterilizar (Kimwipes; placas de Petri de vidrio). Coloque cubreobjetos estériles secos en los pocillos de placas de 24 pocillos estériles con pinzas esterilizadas alcohol de llama. </li><li> Añadir células HeLa (1 ml; volumen 5x utilizado para placas de 96 pocillos) a los pocillos de placas de 24 pocillos que contienen los cubreobjetos de vidrio redondos estériles lavados. Añadir los virus, bacterias y hongos de acuerdo con la plantilla (Tabla 2) en 5x el volumen utilizado para las placas de 96 pocillos, a continuación, se incuba y el proceso tal como se describe en los pasos 6.2.1 a 6.4 anteriormente. </li><li> Después del lavado final, fijar las células para microscopía inundando la corredera con metanol y permitiendo que se evapore. Almacenar las placas a temperatura ambiente hasta que la tinción. </li><li> Para la microscopía de campo brillante (1,000x aumento original final) llenar los pocillos que contienen cubreobjetos fijados con metanol con agua desionizada. Inmediatamente aspirar agua. Cubra cada cubreobjetos con Gramos violeta cristal. Lave cubreobjetos libre de mancha no ligada (agua desionizada). Cubreobjetos secos in situ a continuación, se adhieren con medio a una diapositiva de marcado de montaje conjunto duro (Figura 3). </li><li> Para la microscopía (objetivo 100x; 1,000x definitiva inicial de aumento) fluorescente de lavado cubreobjetos libre de metanol esencialmente como se describe en el paso 7.4. Seque los cubreobjetos en los pocillos. <ol><li> Después del secado, retire la cubierta se desliza y colocarlos en portaobjetos etiquetados. A continuación, añadir una cantidad suficiente de 1:20 dilución de isotiocianato de fluoresceína (FITC) y conjugado con virus herpes simplex tipo 1 + 2 anticuerpo gD para cubrir el cubreobjetos (1-5 l). </li><li> Incubar los portaobjetos en una cámara húmeda a 37 ° C durante 30 minutos. Después de la incubación, lavar los cubreobjetos en 4 cambios de PBS. </li><li> Después del lavado final, devuelva el cubreobjetos al portaobjetos etiquetados. Manchar con 4 &#39;, 6-diamino-2-fenilindol (DAPI; cámara de humedad, 37 ° C durante 30 minutos). Después de incubación, lavar los cubreobjetos en 4 Changes de PBS, a continuación, adhiera a la diapositiva etiquetados con juego duro medio de montaje. </li><li> Dejar que el medio de montaje para curar durante 24 horas a temperatura ambiente en la oscuridad. Examinar los cubreobjetos bajo petróleo objetivo ya sea en un microscopio de campo claro o microscopio de fluorescencia con filtros de corte FITC y DAPI. Examinar imágenes de al menos 50 campos (100 células por mínima organismo) para la co-localización (Figura 4). </li></ol></li></ol>

The authors have nothing to disclose.

Actualmente no hay información disponible sobre las interacciones complejas entre permanente a los miembros semi-permanentes del microbioma de acogida que se cruzan múltiples dominios taxonómicos, es decir, procariotas, eucariotas y virales. Por lo tanto, hemos desarrollado un novedoso sistema de modelo in vitro para estudiar la iniciación del biofilm por S. aureus y C. albicans en HSV-1 o HSV-2 infectadas 229 células HeLa (HeLa) 38. El sistema modelo de célu...

<html> El microbioma humano incluye diversos organismos de varios reinos taxonómicos que comparten regiones geográficas en el cuerpo. La adherencia a las superficies celulares es un primer paso esencial en la formación de biopelículas, que es parte del proceso de colonización microbioma. Incluido en el microbioma puede haber virus que causan infecciones crónicas y persistentes. La infección de células crónica por estos virus puede causar una alteración en la disponibilidad del receptor putativo. 1,2 Además, la entrada de la célula por patógenos intracelulares también podría afectar a la fluidez de membrana host / hidrofobicidad que a su vez puede alterar la unión de otros miembros microbioma, incluyendo bacterias y hongos . Con el fin de entender las interacciones que pueden ocurrir entre estos múltiples patógenos que co-localizar en las mismas regiones geográficas del huésped humano, debemos ser capaces de estudiar la interacción de los agentes patógenos que representan el espectro de los reinos taxonómicos presentes en la superficie de la mucosa. t &quot;&gt; El Herpesviridae son una familia de microbios presentes en el 100% de los seres humanos como miembros permanentes del microbioma 3,4. Además, pueden también ser derramada persistente tanto en presencia como en ausencia de síntomas. En concreto, el virus herpes simplex-1 y herpes simplex virus-2 (HSV-1 y HSV-2, respectivamente) son miembros permanentes del microbioma en el oronasopharynx y el tracto genital. en individuos inmunocompetentes, tanto HSV-1 y HSV-2 causa gingivoestomatitis, así como el herpes genital 5-8. en estos sitios, el VHS causa una infección latente, caracterizada por necrosis tumoral asintomática crónica persistente derramamiento viral 9. entrada del VHS en células da lugar a alteraciones en la expresión superficial de nectins, sulfato de heparán, balsas de lípidos y herpesvirus mediador de la entrada / receptor del factor de (HVEM / TNFr) 10-25. Estos receptores representan potencialmente compartidos para algunas bacterias y hongos, por ejemplo, S. aureus y C. albicans, que mientras que los patógenos oportunistas,También puede residir en calidad de miembros de la mucosa del microbioma oronasopharynx 26,27. Dentro de la oronasopharynx S. aureus y C. albicans ocupan dos sitios distintos de la colonización. En los anfitriones con los dientes naturales, la mucosa oral es compartida por HSV-1 y C. albicans, mientras que los orificios nasales nasal anterior están ocupados por S. aureus 28. Sin embargo, a pesar de los hallazgos in vitro que S. aureus se adhiere a las células epiteliales de la boca, 29,30 S. aureus es poca frecuencia aisladas de muestras orales cuando está presente el tejido normal 29,30. Poco se sabe en relación con nichos tracto genital co-colonización más allá de los hallazgos clínicos que S. aureus se asocia con la vaginitis aerobia, que se caracteriza por la inflamación genital, la descarga y la dispareunia, mientras que C. albicans produce lesiones de la mucosa similar a la observada en la cavidad oral 31-35. Por lo tanto, aunque estos miembros de la microbi oral y genitalome reinos taxonómicos transversales poco se conoce acerca de su interacción ya que afecta a su capacidad para iniciar la formación de biopelículas mediante la adhesión a la superficie de la célula huésped 5. Este protocolo se ha aplicado de manera efectiva para determinar las consecuencias funcionales de co-colonización / infección.

<table border="0" cellpadding="0" cellspacing="0" width="1185">
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:391px;">C.albicans</td>
			<td style="width:195px;"></td>
			<td style="width:119px;"></td>
			<td style="width:481px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:391px;">BBL Sabouraud Dextrose</td>
			<td style="width:195px;">BD</td>
			<td style="width:119px;">211584</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:391px;">Fungisel Agar</td>
			<td style="width:195px;">Dot Scientific</td>
			<td style="width:119px;">7205A</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:391px;">S.aureus</td>
			<td style="width:195px;"></td>
			<td style="width:119px;"></td>
			<td style="width:481px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:391px;">Mannitol Salt Agar</td>
			<td style="width:195px;">Troy Biologicals</td>
			<td style="width:119px;">7143B</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:391px;">Sheep blood agar</td>
			<td style="width:195px;">Troy Biologicals</td>
			<td style="width:119px;">221239</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:391px;">Hela cells</td>
			<td style="width:195px;"></td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:391px;">1xDMEM (Dubelcco&#39;s Modified Eagle Medium, with 4.5 g/L glucose and L-glutamine, without sodium pyruvate</td>
			<td style="width:195px;">Corning</td>
			<td style="width:119px;">10-017-CM</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:391px;">Gentamicin 50mg/ml</td>
			<td style="width:195px;">Sigma</td>
			<td style="width:119px;">1397</td>
			<td>50&#181;g/ml final concentration in the complete DMEM</td>
		</tr>
		<tr height="19">
			<td height="19" style="height:19px;width:391px;">Trypsin EDTA (0.05% Trypsin, 0.53M EDTA)Solution 1X</td>
			<td style="width:195px;">Corning</td>
			<td>25-052-CI</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:391px;">Fetal Bovine Serum</td>
			<td style="width:195px;">Atlanta Biologicals</td>
			<td style="width:119px;">S11150</td>
			<td>10% final concentration in the complete DMEM</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:391px;">Other medium and reagents</td>
			<td style="width:195px;"></td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:391px;">ONPG</td>
			<td style="width:195px;">Thermo Scientific</td>
			<td style="width:119px;">34055</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:391px;">Ultra-Pure X gal</td>
			<td style="width:195px;">Invitrogen</td>
			<td style="width:119px;">15520-018</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:391px;">1x HBSS (Hanks&#39; Balanced Salt Solution)</td>
			<td style="width:195px;">Corning</td>
			<td style="width:119px;">20-021-CV</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:391px;">1XPBS</td>
			<td style="width:195px;">Dot Scientific</td>
			<td style="width:119px;">30042-500</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:391px;">RIPA Lysis</td>
			<td style="width:195px;">Life Technologies</td>
			<td style="width:119px;">89901</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:391px;">Staining</td>
			<td style="width:195px;"></td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:391px;">Methanol</td>
			<td style="width:195px;">Fisher Scientific</td>
			<td style="width:119px;">A433P-4</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:391px;">HSV 1&#38;2, specific for gD</td>
			<td style="width:195px;">ViroStat</td>
			<td style="width:119px;">196</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:391px;">DAPI</td>
			<td style="width:195px;">SIGMA</td>
			<td style="width:119px;">D8417-5MG</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:391px;">Gram Crystal Violet</td>
			<td style="width:195px;">Troy Biologicals</td>
			<td style="width:119px;">212527</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:391px;">Supplies</td>
			<td style="width:195px;"></td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="29">
			<td height="29" style="height:29px;width:391px;">Petri dish 100X15</td>
			<td style="width:195px;">Dot Scientific</td>
			<td style="width:119px;">229693&#160;</td>
			<td></td>
		</tr>
		<tr height="29">
			<td height="29" style="height:29px;width:391px;">Petri dish 150X15</td>
			<td style="width:195px;">Kord Valmark</td>
			<td style="width:119px;">2902</td>
			<td></td>
		</tr>
		<tr height="26">
			<td height="26" style="height:26px;width:391px;">96-Well plates</td>
			<td style="width:195px;">Evergreen Scientific</td>
			<td style="width:119px;">222-8030-01F</td>
			<td></td>
		</tr>
		<tr height="26">
			<td height="26" style="height:26px;width:391px;">24-well plates</td>
			<td style="width:195px;">Evergreen Scientific</td>
			<td style="width:119px;">222-8044-01F</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:391px;">Culture tubes 100x13</td>
			<td style="width:195px;">Thomas Scientific</td>
			<td style="width:119px;">9187L61</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:391px;">Cover slip circles, 12mm</td>
			<td style="width:195px;">Deckglaser</td>
			<td style="width:119px;">CB00120RA1</td>
			<td></td>
		</tr>
	</tbody>
</table>

determination of biofilm initiation on virus-infected cells by bacteria and fungi

El estudio de las interacciones polimicrobianas a través de los reinos taxonómicos que incluyen hongos, bacterias y virus no se han examinado previamente con respecto a cómo los miembros virales de la microbioma afectan las interacciones microbio posteriores con estas células huésped infectadas por virus. La cohabitación de virus con bacterias y hongos es principalmente presente en las superficies de la mucosa de la cavidad oral y el tracto genital. células de la mucosa, particularmente aquellos con infecciones virales latentes crónicas o persistentes persistentes, podrían tener un impacto significativo en los miembros de la microbioma través de la alteración del virus en el número y tipo de receptores expresados. Modificación en la arquitectura de la membrana de la célula huésped se traduciría en la capacidad alterada de los miembros posteriores de la flora normal y patógenos oportunistas para iniciar el primer paso en la formación de biopelículas, es decir, la adhesión. Este estudio describe un método para la cuantificación y control visual del efecto de HSV en el inicio de biofilm formación (adherencia) de S. aureus y C. albicans.

El nivel de fiabilidad de los datos que se pueden obtener a partir sistema descrito en este informe se muestra en la Figura 2 af 38. Mediante el uso de este sistema de la modulación de la interacción de estafilococos y hongos con las células infectadas por virus y sus efectos en la adherencia de cada uno puede ser delineado. Estos tipos de estudios requieren el examen microscópico de la interacción tal como se muestra en las figuras 3 y <...

Watch this Scientific Journal Video about Determination of Biofilm Initiation on Virus-infected Cells by Bacteria and Fungi at JoVE.com

Determination of Biofilm Initiation on Virus-infected Cells by Bacteria and Fungi

A method is described herein for the determination of inter-Kingdom association and competition (bacterial and fungal) for adherence to virus-infected HeLa cell monolayers. This protocol can be extended to multiple combinations of prokaryotes, eukaryotes, and viruses.

Determinación de Biofilm Iniciación, el virus de las células infectadas por bacterias y hongos

The study of polymicrobial interactions across the taxonomic kingdoms that include fungi, bacteria and virus have not been previously examined with ...

determination-biofilm-initiation-on-virus-infected-cells-bacteria

Research

JoVE Journal

Immunology and Infection

9.6K vistas.  Midwestern University. A method is described herein for the determination of inter-Kingdom association and competition (bacterial and fungal) for adherence to virus-infected HeLa cell monolayers. This protocol can be extended to multiple combinations of prokaryotes, eukaryotes, and viruses.

Video: Determination of Biofilm Initiation on Virus-infected Cells by Bacteria and Fungi

Pseudomonas aeruginosa and Saccharomyces cerevisiae Biofilm in Flow Cells

Many microbial cells have the ability to form sessile microbial communities defined as biofilms that have altered physiological and pathological properties compared to free living microorganisms. Biofilms in nature are often difficult to investigate and reside under poorly defined conditions1. Using a transparent substratum it is possible to device a system where simple biofilms can be examined in a non-destructive way in real-time: here we demonstrate the assembly and operation of a flow cell model system, for in vitro 3D studies of microbial biofilms generating high reproducibility under well-defined conditions2,3.
The system consists of a flow cell that serves as growth chamber for the biofilm. The flow cell is supplied with nutrients and oxygen from a medium flask via a peristaltic pump and spent medium is collected in a waste container. This construction of the flow system allows a continuous supply of nutrients and administration of e.g. antibiotics with minimal disturbance of the cells grown in the flow chamber. Moreover, the flow conditions within the flow cell allow studies of biofilm exposed to shear stress. A bubble trapping device confines air bubbles from the tubing which otherwise could disrupt the biofilm structure in the flow cell.
The flow cell system is compatible with Confocal Laser Scanning Microscopy (CLSM) and can thereby provide highly detailed 3D information about developing microbial biofilms. Cells in the biofilm can be labeled with fluorescent probes or proteins compatible with CLSM analysis. This enables online visualization and allows investigation of niches in the developing biofilm. Microbial interrelationship, investigation of antimicrobial agents or the expression of specific genes, are of the many experimental setups that can be investigated in the flow cell system.

Pseudomonas aeruginosa and Saccharomyces cerevisiae Biofilm in Flow Cells

Protocol describing the application of a flow cell system for growing and analyzing microbial biofilms for Confocal Laser Scanning Microscopy (CLSM).

Pseudomonas aeruginosa y Biofilm Saccharomyces cerevisiae en las celdas de flujo

Many microbial cells have the ability to form sessile microbial communities defined as biofilms that have altered physiological and pathological ...

Investigación

Inmunología e Infección

Microtiter Dish Biofilm Formation Assay

Biofilms are communities of microbes attached to surfaces, which can be found in medical, industrial and natural settings. In fact, life in a biofilm probably represents the predominate mode of growth for microbes in most environments. Mature biofilms have a few distinct characteristics. Biofilm microbes are typically surrounded by an extracellular matrix that provides structure and protection to the community. Microbes growing in a biofilm also have a characteristic architecture generally comprised of macrocolonies (containing thousands of cells) surrounded by fluid-filled channels. Biofilm-grown microbes are also notorious for their resistance to a range of antimicrobial agents including clinically relevant antibiotics.
The microtiter dish assay is an important tool for the study of the early stages in biofilm formation, and has been applied primarily for the study of bacterial biofilms, although this assay has also been used to study fungal biofilm formation. Because this assay uses static, batch-growth conditions, it does not allow for the formation of the mature biofilms typically associated with flow cell systems. However, the assay has been effective at identifying many factors required for initiation of biofilm formation (i.e, flagella, pili, adhesins, enzymes involved in cyclic-di-GMP binding and metabolism) and well as genes involved in extracellular polysaccharide production. Furthermore, published work indicates that biofilms grown in microtiter dishes do develop some properties of mature biofilms, such a antibiotic tolerance and resistance to immune system effectors.
This simple microtiter dish assay allows for the formation of a biofilm on the wall and/or bottom of a microtiter dish. The high throughput nature of the assay makes it useful for genetic screens, as well as testing biofilm formation by multiple strains under various growth conditions. Variants of this assay have been used to assess early biofilm formation for a wide variety of microbes, including but not limited to, pseudomonads, Vibrio cholerae, Escherichia coli, staphylocci, enterococci, mycobacteria and fungi.
In the protocol described here, we will focus on the use of this assay to study biofilm formation by the model organism Pseudomonas aeruginosa. In this assay, the extent of biofilm formation is measured using the dye crystal violet (CV). However, a number of other colorimetric and metabolic stains have been reported for the quantification of biofilm formation using the microtiter plate assay. The ease, low cost and flexibility of the microtiter plate assay has made it a critical tool for the study of biofilms.

The assay describes a rapid means to measure early biofilm formation in bacteria and fungi. This method uses a microtiter plate as the substratum for microbial biofilm formation, and the biofilm is visualized using crystal violet strain. The assay provides either a qualitative or quantitative assay for early biofilm formation.

Plato de microtitulación de formación de biopelículas de ensayo

Biofilms are communities of microbes attached to surfaces, which can be found in medical, industrial and natural settings.  In fact, life in a biofilm ...

Following Cell-fate in E. coli After Infection by Phage Lambda

The system comprising bacteriophage (phage) lambda and the bacterium E. coli has long served as a paradigm for cell-fate determination1,2. Following the simultaneous infection of the cell by a number of phages, one of two pathways is chosen: lytic (virulent) or lysogenic (dormant)3,4. We recently developed a method for fluorescently labeling individual phages, and were able to examine the post-infection decision in real-time under the microscope, at the level of individual phages and cells5. Here, we describe the full procedure for performing the infection experiments described in our earlier work5. This includes the creation of fluorescent phages, infection of the cells, imaging under the microscope and data analysis. The fluorescent phage is a "hybrid", co-expressing wild- type and YFP-fusion versions of the capsid gpD protein. A crude phage lysate is first obtained by inducing a lysogen of the gpD-EYFP (Enhanced Yellow Fluorescent Protein) phage, harboring a plasmid expressing wild type gpD. A series of purification steps are then performed, followed by DAPI-labeling and imaging under the microscope. This is done in order to verify the uniformity, DNA packaging efficiency, fluorescence signal and structural stability of the phage stock. The initial adsorption of phages to bacteria is performed on ice, then followed by a short incubation at 35&deg;C to trigger viral DNA injection6. The phage/bacteria mixture is then moved to the surface of a thin nutrient agar slab, covered with a coverslip and imaged under an epifluorescence microscope. The post-infection process is followed for 4 hr, at 10 min interval. Multiple stage positions are tracked such that ~100 cell infections can be traced in a single experiment. At each position and time point, images are acquired in the phase-contrast and red and green fluorescent channels. The phase-contrast image is used later for automated cell recognition while the fluorescent channels are used to characterize the infection outcome: production of new fluorescent phages (green) followed by cell lysis, or expression of lysogeny factors (red) followed by resumed cell growth and division. The acquired time-lapse movies are processed using a combination of manual and automated methods. Data analysis results in the identification of infection parameters for each infection event (e.g. number and positions of infecting phages) as well as infection outcome (lysis/lysogeny). Additional parameters can be extracted if desired.

Following Cell-fate in E. coli After Infection by Phage Lambda

This article describes the procedure for preparing a fluorescently-labeled version of bacteriophage lambda, infection of E. coli bacteria, following the infection outcome under the microscope, and analysis of infection results.

A raíz de la celda de destino en<em&gt; E. coli</em&gt; Después de la infección por fagos Lambda

The system comprising bacteriophage (phage) lambda and the bacterium E. coli has long served as a paradigm for cell-fate determination1,2. Following the ...

Purification and Visualization of Lipopolysaccharide from Gram-negative Bacteria by Hot Aqueous-phenol Extraction

Lipopolysaccharide (LPS) is a major component of Gram-negative bacterial outer membranes. It is a tripartite molecule consisting of lipid A, which is embedded in the outer membrane, a core oligosaccharide and repeating O-antigen units that extend outward from the surface of the cell1, 2. LPS is an immunodominant molecule that is important for the virulence and pathogenesis of many bacterial species, including Pseudomonas aeruginosa, Salmonella species, and Escherichia coli3-5, and differences in LPS O-antigen composition form the basis for serotyping of strains. LPS is involved in attachment to host cells at the initiation of infection and provides protection from complement-mediated killing; strains that lack LPS can be attenuated for virulence6-8. For these reasons, it is important to visualize LPS, particularly from clinical isolates. Visualizing LPS banding patterns and recognition by specific antibodies can be useful tools to identify strain lineages and to characterize various mutants. 
In this report, we describe a hot aqueous-phenol method for the isolation and purification of LPS from Gram-negative bacterial cells. This protocol allows for the extraction of LPS away from nucleic acids and proteins that can interfere with visualization of LPS that occurs with shorter, less intensive extraction methods9. LPS prepared this way can be separated by sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis (PAGE) and directly stained using carbohydrate/glycoprotein stains or standard silver staining methods. Many anti-sera to LPS contain antibodies that cross-react with outer membrane proteins or other antigenic targets that can hinder reactivity observed following Western immunoblot of SDS-PAGE-separated crude cell lysates. Protease treatment of crude cell lysates alone is not always an effective way of removing this background using this or other visualization methods. Further, extensive protease treatment in an attempt to remove this background can lead to poor quality LPS that is not well resolved by any of the aforementioned methods. For these reasons, we believe that the following protocol, adapted from Westpahl and Jann10, is ideal for LPS extraction.

We describe a modified hot aqueous-phenol extraction method for purifying lipopolysaccharide (LPS) from Gram-negative bacteria. Once extracted, the LPS can be subsequently analyzed by SDS-PAGE and visualized by direct staining or Western immunoblot.

La purificación y la visualización de lipopolisacárido de bacterias Gram-negativas por Hot acuosa de fenol-Extracción

Lipopolysaccharide (LPS)  is a major component of Gram-negative bacterial outer membranes. It is a tripartite molecule consisting of  lipid A, which is ...

Use of Image Cytometry for Quantification of Pathogenic Fungi in Association with Host Cells

Studies of the cellular pathogenesis mechanisms of pathogenic yeasts such as Candida albicans, Histoplasma capsulatum, and Cryptococcus neoformans commonly employ infection of mammalian hosts or host cells (i.e. macrophages) followed by yeast quantification using colony forming unit analysis or flow cytometry. While colony forming unit enumeration has been the most commonly used method in the field, this technique has disadvantages and limitations, including slow growth of some fungal species on solid media and low and/or variable plating efficiencies, which is of particular concern when comparing growth of wild-type and mutant strains. Flow cytometry can provide rapid quantitative information regarding yeast viability, however, adoption of flow cytometric detection for pathogenic yeasts has been limited for a number of practical reasons including its high cost and biosafety considerations. Here, we demonstrate an image-based cytometric methodology using the Cellometer Vision (Nexcelom Bioscience, LLC) for the quantification of viable pathogenic yeasts in co-culture with macrophages. Our studies focus on detection of two human fungal pathogens: Histoplasma capsulatum and Candida albicans. H. capsulatum colonizes alveolar macrophages by replicating within the macrophage phagosome, and here, we quantitatively assess the growth of H. capsulatum yeasts in RAW 264.7 macrophages using acridine orange/propidium iodide staining in combination with image cytometry. Our method faithfully recapitulates growth trends as measured by traditional colony forming unit enumeration, but with significantly increased sensitivity. Additionally, we directly assess infection of live macrophages with a GFP-expressing strain of C. albicans. Our methodology offers a rapid, accurate, and economical means for detection and quantification of important human fungal pathogens in association with host cells.

Here, we demonstrate how image cytometry can be used for quantification of pathogenic fungi in association with host cells in culture. This technique can be used as an alternative to CFU enumeration.

El uso de citometría de imagen para la cuantificación de hongos patógenos en asociación con las células huésped

Studies of the cellular pathogenesis mechanisms of pathogenic yeasts such as Candida albicans, Histoplasma capsulatum, and Cryptococcus neoformans ...

Application of Fluorescent Nanoparticles to Study Remodeling of the Endo-lysosomal System by Intracellular Bacteria

Fluorescent nanoparticles (NPs) with desirable chemical, optical and mechanical properties are promising tools to label intracellular organelles. Here, we introduce a method using gold-BSA-rhodamine NPs to label the endo-lysosomal system of eukaryotic cells and monitor manipulations of host cellular pathways by the intracellular pathogen Salmonella enterica. The NPs were readily internalized by HeLa cells and localized in late endosomes/lysosomes. Salmonella infection induced rearrangement of the vesicles and accumulation of NPs in Salmonella-induced membrane structures. We deployed the Imaris software package for quantitative analyses of confocal microscopy images. The number of objects and their size distribution in non-infected cells were distinct from the ones in Salmonella-infected cells, indicating extremely remodeling of the endo-lysosomal system by WT Salmonella.

This article describes methods for the synthesis and fluorescent labeling of nanoparticles (NPs). The NPs were applied in pulse-chase experiments to label the endo-lysosomal system of eukaryotic cells. Manipulation of the endo-lysosomal system by activities of the intracellular pathogen Salmonella enterica were followed by live cell imaging and quantified.

Aplicación de nanopartículas fluorescentes para estudiar Remodelación del Sistema Endo-lisosomal por bacterias intracelulares

Fluorescent nanoparticles (NPs) with desirable chemical, optical and mechanical properties are promising tools to label intracellular organelles. Here, we ...

T Cells Capture Bacteria by Transinfection from Dendritic Cells

Recently, we have shown, contrary to what is described, that CD4+ T cells, the paradigm of adaptive immune cells, capture bacteria from infected dendritic cells (DCs) by a process called transinfection. Here, we describe the analysis of the transinfection process, which occurs during the course of antigen presentation. This process was unveiled by using CD4+ T cells from transgenic OTII mice, which bear a T cell receptor (TCR) specific for a peptide of ovoalbumin (OVAp), which therefore can form stable immune complexes with infected dendritic cells loaded with this specific OVAp. The dynamics of green fluorescent protein (GFP)-expressing bacteria during DC-T cell transmission can be monitored by live-cell imaging and the quantification of bacterial transinfection can be performed by flow cytometry. In addition, transinfection can be quantified by a more sensitive method based in the use of gentamicin, a non-permeable aminoglycoside antibiotic killing extracellular bacteria but not intracellular ones. This classical method has been used previously in microbiology to study the efficiency of bacterial infections. We hereby explain the protocol of the complete process, from the isolation of the primary cells to the quantification of transinfection.

Here a protocol is presented to measure bacterial capture by CD4+ T cells which occurs during antigen presentation via transinfection from pre-infected dendritic cells (DC). We show how to perform the necessary steps: isolation of primary cells, infection of DC, DC/T cell conjugate formation, and measurement of bacterial T cell transfection.

Células T Captura bacterias por transinfection de células dendríticas

Recently, we have shown, contrary to what is described, that CD4+ T cells, the paradigm of adaptive immune cells, capture bacteria from infected dendritic ...

Phenotypic and Functional Analysis of Activated Regulatory T Cells Isolated from Chronic Lymphocytic Choriomeningitis Virus-infected Mice

Regulatory T (Treg) cells, which express Foxp3 as a transcription factor, are subsets of CD4+ T cells. Treg cells play crucial roles in immune tolerance and homeostasis maintenance by regulating the immune response. The primary role of Treg cells is to suppress the proliferation of effector T (Teff) cells and the production of cytokines such as IFN-&#947;, TNF-&#945;, and IL-2. It has been demonstrated that Treg cells&#39; ability to inhibit the function of Teff cells is enhanced during persistent pathogen infection and cancer development. To clarify the function of Treg cells under resting or inflamed conditions, a variety of in vitro suppression assays using mouse or human Treg cells have been devised. The main aim of this study is to develop a method to compare the differences in phenotype and suppressive function between resting and activated Treg cells. To isolate activated Treg cells, mice were infected with lymphocytic choriomeningitis virus (LCMV) clone 13 (CL13), a chronic strain of LCMV. Treg cells isolated from the spleen of LCMV CL13-infected mice exhibited both the activated phenotype and enhanced suppressive activity compared with resting Treg cells isolated from na&#239;ve mice. Here, we describe the basic protocol for ex vivo phenotype analysis to distinguish activated Treg cells from resting Treg cells. Furthermore, we describe a protocol for the measurement of the suppressive activity of fully activated Treg cells.

Here, we describe a protocol to analyze the phenotype of regulatory T (Treg) cells isolated from na&#239;ve and chronic lymphocytic choriomeningitis virus-infected mice. In addition, we provide a process to evaluate the suppressive activity of the Treg cells.

El análisis fenotípico y funcional de las células reguladoras T activadas Aislado de la coriomeningitis linfocítica crónica por el virus ratones infectados

Regulatory T (Treg) cells, which express Foxp3 as a transcription factor, are subsets of CD4+ T cells. Treg cells play crucial roles in immune tolerance ...

Visualizing the Effects of Sputum on Biofilm Development Using a Chambered Coverglass Model

Biofilms consist of groups of bacteria encased in a self-secreted matrix. They play an important role in industrial contamination as well as in the development and persistence of many health related infections. One of the most well described and studied biofilms in human disease occurs in chronic pulmonary infection of cystic fibrosis patients. When studying biofilms in the context of the host, many factors can impact biofilm formation and development. In order to identify how host factors may affect biofilm formation and development, we used a static chambered coverglass method to grow biofilms in the presence of host-derived factors in the form of sputum supernatants. Bacteria are seeded into chambers and exposed to sputum filtrates. Following 48 hr of growth, biofilms are stained with a commercial biofilm viability kit prior to confocal microscopy and analysis. Following image acquisition, biofilm properties can be assessed using different software platforms. This method allows us to visualize key properties of biofilm growth in presence of different substances including antibiotics.

This protocol describes the visualization of biofilm development following exposure to host-factors using a slide chamber model. This model allows for direct visualization of biofilm development as well as analysis of biofilm parameters using computer software programs.

La visualización de los Efectos de esputo en el desarrollo del biofilm mediante un modelo de Septadas cubreobjetos

Biofilms consist of groups of bacteria encased in a self-secreted matrix. They play an important role in industrial contamination as well as in the ...

Optical Screening of Novel Bacteria-specific Probes on Ex Vivo Human Lung Tissue by Confocal Laser Endomicroscopy

Improving the speed and accuracy of bacterial detection is important for patient stratification and to ensure the appropriate use of antimicrobials. To achieve this goal, the development of diagnostic techniques to recognize bacterial presence in real-time at the point-of-care is required. Optical imaging for direct identification of bacteria within the host is an attractive approach. Several attempts at chemical probe design and validation have been investigated, however none have yet been successfully translated into the clinic. Here we describe a method for ex vivo validation of bacteria-specific probes for identification of bacteria within the distal lung, imaged by fibered confocal fluorescence microscopy (FCFM). Our model used ex vivo human lung tissue and a clinically approved confocal laser endomicroscopy (CLE) platform to screen novel bacteria-specific imaging compounds, closely mimicking imaging conditions expected to be encountered with patients. Therefore, screening compounds by this technique provides confidence of potential clinical tractability.

Optical Screening of Novel Bacteria-specific Probes on Ex Vivo Human Lung Tissue by Confocal Laser Endomicroscopy

This technique describes an efficient screening process for evaluating bacteria-specific optical imaging agents within ex vivo human lung tissue, by fibered confocal fluorescence microscopy for the rapid identification of small molecule chemical probe-candidates with translatable potential.

Sondas de detección óptica de novela bacterias específicas en el tejido de pulmón humano Ex Vivo por láser Confocal Endomicroscopy

Improving the speed and accuracy of bacterial detection is important for patient stratification and to ensure the appropriate use of antimicrobials. To ...