Este trabajo es apoyado por becas de investigación de los Institutos Nacionales de Salud (HL068915; HL088206), un Premio al Investigador Nuevo en el Fondo de Investigación Thrasher, y las contribuciones al Fondo de conducción cardiaca en el Hospital de Niños de Boston.

Parte 1: Montar la construcción de moldes de fundición <ol><li> Use una hoja de afeitar para reducir a la mitad el tubo de silicona (VWR) y cortarlo en tres pedazos cm de largo. </li><li> Coloque una gota de RTV adhesivo implantes de silicona de calidad (Rhodia) en el interior de cada extremo de la tubería. </li><li> Rápidamente coloque un pedazo pequeño (1 cm x 1 cm) de malla de poliéster (McMaster-Carr) sobre la caída de adhesivo de silicona y alinearla con el extremo de la tubería. Esto proporcionará una superficie ligeramente elevada y plana para la conexión construir. Repita para el otro extremo. </li><li> Deje que el molde para secar a temperatura ambiente durante 3 días. Es útil para hacer moldes de 20 a 30 a la vez, ya que son esencialmente desechables. </li><li> Una vez que el adhesivo esté completamente seco, almacenar estos moldes en un vaso lleno de etanol al 70% hasta que se necesiten. Este paso ayudará a esterilizar los moldes y el producto terminado se muestra en la Figura 1. </li></ol> Parte 2: Preparación para el aislamiento de células con mioblastos <ol><li> Diluir 1 mg laminina (Sigma) en 250 ml de 0,22 micras, esterilizada por filtración de buffer fosfato salino (PBS) que contiene 1% de penicilina / estreptomicina (Invitrogen) y el 1% Fungizone (Invitrogen). </li><li> Escudo 150 mm placas de cultivo tisular (BD Falcon) con 4 ml de la solución diluida de laminina paso 1.1 e incubar a 37 º C durante al menos 4 horas antes de la galjanoplastia mioblastos esqueléticos primaria. </li><li> Hacer que el medio de mioblastos mediante la mezcla de F-10 de Ham mezcla de nutrientes (Sigma) con 20% de SFB (Atlanta Biologicals), 5 ng / L Factor de crecimiento de fibroblastos (Promega), 1% penicilina / estreptomicina (Invitrogen), y el 1% Fungizone ( Invitrogen). </li><li> Prepare la solución de los músculos esqueléticos digestión mediante la disolución de 1 g de ~ 295 U / mg de colagenasa 2 (Worthington) en 100 ml de 2,4 U / mL Dispasa-2 (Roche). Añadir 0,037 g de CaCl 2 y mezclar bien. Filtro de esterilizar el tampón de digestión con un disco de 0.2 micras de filtro instalado en una jeringa de 10 ml y almacenar alícuotas a -20 ° C. Coloque la cantidad necesaria para la digestión de los tejidos a 37 ° C, junto con los medios de comunicación de mioblastos. </li></ol> Parte 3: Aislamiento de mioblastos de músculo esquelético <ol><li> El uso de pinzas y tijeras pequeñas, eliminar músculos paravertebrales de la muerte neonatal ratas Lewis por corte en la parte posterior de la médula espinal, quitando la piel y las capas de la fascia y los músculos de la escisión. </li><li> En una campana de cultivo de tejidos, el lugar de los músculos extirpado en un tubo cónico de 50 ml (BD Falcon) llena con 40 ml de solución salina Hanks 1X (Balanced HBSS) (Invitrogen) en el hielo. Dejar que las tiras musculares que se depositan en el fondo del tubo y retire con cuidado la mayor parte de los restos de líquido y sangre por succión al vacío con una pipeta Pasteur estéril en una campana de la cultura (Baker). </li><li> Vierta las piezas del músculo recogieron sobre una placa de cultivo de 150 mm y eliminar la mayor cantidad de líquido que queda como sea posible con la succión. Usando dos de un solo filo hojas de afeitar pelos en el tejido hasta formar una pasta espesa. Vierta precalentado solución de digestión de la pasta y la transferencia de la mezcla a un tubo de 50 ml fresca con una pipeta de 10 ml. Durante la digestión enzimática, el tejido es de vez en cuando triturado (sin burbujas) con una pipeta de 10 mL equipado en un teléfono inalámbrico con una pipeta-Aid (Drummond). Una vez más, permitir que el tejido para resolver y eliminar el exceso de líquido. </li><li> Coloque el tubo en una plataforma oscilante y digerir a 37 º C durante unos 30 minutos. </li><li> Una vez que el músculo está licuado, pasar a través de un colador celular 70 micras (BD Falcon) y se centrifuga a temperatura ambiente durante 10 minutos a 600 xg (Beckman GP). Con una pipeta de Pasteur y de succión, retire la mayor cantidad de líquido posible y resuspender el precipitado con 10 ml de medio de mioblastos caliente. </li><li> Pre-placa de las células en una placa de 150 mm sin recubrimiento de cultivo de tejidos durante 15 minutos para ayudar a eliminar los fibroblastos. </li><li> Transferencia de las células que aún no han conectado a la cultureware laminina recubierto y se diluye de modo que no es un plato para cada 1 a 2 crías de rata. Colocar la placa en una incubadora humidificada conjunto a 37 º C con CO2 al 5%. </li></ol> Parte 4: Usar las construcciones de ingeniería tisular (5 ml) <ol><li> Después de 1 a 2 días, retire 10 de los 150 mm placas de cultivo de tejidos de mioblastos de la incubadora, lavar dos veces con 37 ° C PBS 1X, y añadir 4 ml de agua tibia 0,05% de tripsina-EDTA a cada plato. Retorno de las placas a la incubadora durante 5 min. </li><li> Cosecha de los mioblastos separado de las placas en la cubierta la cultura y recoger el líquido en un tubo de 50 ml (BD Falcon). Utilizar 10 ml de medio de mioblastos para lavar todos los platos y combinar esto con las células en el tubo de centrífuga. Que sedimenten las células a temperatura ambiente durante 10 minutos a 600 xg (Beckman GP) y eliminar el exceso de líquido como se describe en el paso 3.5. </li><li> Resuspender las células con mioblastos en 1,6 ml de medio de mioblastos y el lugar en el hielo. </li><li> Con unas pinzas, retire con cuidado la construcción de 4 moldes de paso 1,5 y enjuague dos veces con PBS 1X. Vacío de aspiración de todos los rastros de PBS con una pipeta Pasteur antes de colocar cada molde en un cu tejidos de 6 pocilloslture placa (BD Falcon). </li><li> Reúna a los otros reactivos necesarios para la preparación de la construcción (F10 Jamón de 10X, los antibióticos, el colágeno tipo 1 [3,9 mg / ml] [6] y Matrigel ™) en el hielo y mantener los medios de comunicación de mioblastos a 37 º C. Combine 500 l 10 veces más de Ham F10, 100 l de penicilina / estreptomicina, 100 Fungizone l, 1,6 mL de colágeno, y 750 ™ l Matrigel en un tubo cónico de 15 ml. Mezclar la solución durante 10 segundos utilizando una Mini-vórtice (VWR) establece en 10 y el lugar en el hielo. </li><li> A continuación, añadir 80 l de NaHCO3 y la suspensión de mioblastos a partir del paso de 3,3 a la mezcla del paso 3.5. Vortex toda la mezcla durante 10 segundos y volver el tubo al cubo de hielo durante unos minutos para limpiar la solución de burbujas. </li><li> Con cuidado, tire la mezcla en los moldes antes de que comience a solidificarse con una pipeta de 10 ml. Cada molde tiene capacidad para aproximadamente 1 ml de líquido viscoso. Trate de evitar la introducción de burbujas de aire durante este procedimiento. </li><li> Transferir cuidadosamente la placa que contiene las construcciones de fundición a la incubadora. Después de aproximadamente 30 minutos, retire las construcciones solidificado de la incubadora y añadir con cuidado a cada medio de mioblastos y para cubrir el tejido construir. Devolver la placa a la incubadora (Figura 2). </li></ol> Parte 5: Los resultados representativos Cuando este protocolo se ejecuta correctamente, la construcción del tejido de mioblastos que contienen está listo para la implantación in vivo (es decir, cuando se saca del molde) o más en los análisis in vitro después de 2 días. <img src="/files/ftp_upload/1137/Figure1.jpg" alt="" /> Figura 1. Ejemplos de completar la construcción de moldes (ver Paso 1.5). <img src="/files/ftp_upload/1137/Figure2.jpg" alt="" width="400" height="321" /> Figura 2. A solidificado mioblastos tejido que contiene la construcción [1]. <img src="/files/ftp_upload/1137/Figure3.jpg" alt="" /> Figura 3. Perfiles en H &amp; E manchadas de un tejido que contiene la construcción de mioblastos. &quot;A&quot; representa un corte longitudinal y &quot;B&quot; muestra una sección transversal.

<ol>
	<li>Choi, Y. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cardiac+conduction+through+engineered+tissue.">Cardiac conduction through engineered tissue.</a> Am J Pathol. 169 (1), 72-85 (2006).</li><li>Rando, T. A., Blau, H. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Primary+mouse+myoblast+purification,+characterization,+and+transplantation+for+cell-mediated+gene+therapy.">Primary mouse myoblast purification, characterization, and transplantation for cell-mediated gene therapy.</a> J Cell Biol. 125 (6), 1275-1287 (1994).</li><li>Blau, H. M., Webster, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Isolation+and+characterization+of+human+muscle+cells.">Isolation and characterization of human muscle cells.</a> Proc Natl Acad Sci U S A. 78 (9), 5623-5627 (1981).</li><li>Powell, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tissue-engineered+human+bioartificial+muscles+expressing+a+foreign+recombinant+protein+for+gene+therapy.">Tissue-engineered human bioartificial muscles expressing a foreign recombinant protein for gene therapy.</a> Hum Gene Ther. 10 (4), 565-577 (1999).</li><li>Vandenburgh, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tissue-engineered+skeletal+muscle+organoids+for+reversible+gene+therapy.">Tissue-engineered skeletal muscle organoids for reversible gene therapy.</a> Hum Gene Ther. 7 (17), 2195-2200 (1996).</li><li>Gallop, P. M., Seifter, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Preparation+and+Properties+of+Soluble+Collagens.">Preparation and Properties of Soluble Collagens.</a> Methods in Enzymology. 6, 635-641 (1963).</li></ol>

Los experimentos con animales se realizaron de acuerdo con las directrices y normas establecidas por el Cuidado de Animales institucional y el empleo en el Hospital de Niños de Boston.

Los moldes en los que será la construcción de tejido reparto se puede hacer en cualquier forma y tamaño, sin embargo, es necesario que haya al menos dos puntos de fijación. De lo contrario, la matriz y las células forman una estructura esférica y las células mueren. En el presente Protocolo, se describe el uso de una malla de poliéster para este propósito, sin embargo, también hemos utilizado con éxito una malla de acero inoxidable. Obviamente, los moldes más grandes requieren más células, y un mayor volum...

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		<div>
		<table border="1">
		<thead>
		<tr>
		<th>Material Name</th>
		<th>Type</th>
		<th>Company</th>
		<th>Catalogue Number</th>
		<th>Comment</th>
		</tr>
		</thead>
		<tbody>
		
<tr>
<td>Silicone tubing</td>
<td>&nbsp;</td>
<td>VWR</td>
<td>60985-724</td>
<td>&nbsp;</td>
<tr>
<td>Silicone adhesive</td>
<td>&nbsp;</td>
<td>Rhodia Silicones</td>
<td>MED ADH 4300 RTV</td>
<td>&nbsp;</td>
<tr>
<td>Polyester Mesh</td>
<td>&nbsp;</td>
<td>McMaster-Carr</td>
<td>93185T17</td>
<td>&nbsp;</td>
<tr>
<td>Laminin</td>
<td>&nbsp;</td>
<td>Sigma</td>
<td>L2020</td>
<td>&nbsp;</td>
<tr>
<td>Nutrient Mixture F-10 HAM</td>
<td>&nbsp;</td>
<td>Sigma</td>
<td>N6908</td>
<td>&nbsp;</td>
<tr>
<td>Fetal Bovine Serum</td>
<td>&nbsp;</td>
<td>Atlanta Biologicals</td>
<td>S11550</td>
<td>&nbsp;</td>
<tr>
<td>Penicillin/Streptomycin</td>
<td>&nbsp;</td>
<td>Invitrogen</td>
<td>15140</td>
<td>&nbsp;</td>
<tr>
<td>Fungizone</td>
<td>&nbsp;</td>
<td>Invitrogen</td>
<td>15290-018</td>
<td>&nbsp;</td>
<tr>
<td>Dispase-2</td>
<td>&nbsp;</td>
<td>Roche</td>
<td>10295825001</td>
<td>&nbsp;</td>
<tr>
<td>Collagenase 2</td>
<td>&nbsp;</td>
<td>Worthington</td>
<td>46H8863</td>
<td>&nbsp;</td>
<tr>
<td>Basic Fibroblast Growth Factor</td>
<td>&nbsp;</td>
<td>Promega</td>
<td>G5071</td>
<td>&nbsp;</td>
<tr>
<td>150 mm tissue culture dishes</td>
<td>&nbsp;</td>
<td>BD Falcon</td>
<td>353025</td>
<td>&nbsp;</td>
<tr>
<td>0.05% (1X) Trypsin-EDTA</td>
<td>&nbsp;</td>
<td>Gibco</td>
<td>25300</td>
<td>&nbsp;</td>
<tr>
<td>1X Hanks Balanced Salt Solution</td>
<td>&nbsp;</td>
<td>Invitrogen</td>
<td>14170-112</td>
<td>&nbsp;</td>
<tr>
<td>7.5% NaHCO3</td>
<td>&nbsp;</td>
<td>Gibco</td>
<td>25080-094</td>
<td>&nbsp;</td>
<tr>
<td>70 &mu;m cell strainer</td>
<td>&nbsp;</td>
<td>BD Falcon</td>
<td>352350</td>
<td>&nbsp;</td>
<tr>
<td>6-well plates</td>
<td>&nbsp;</td>
<td>BD Falcon</td>
<td>353046</td>
<td>&nbsp;</td>
<tr>
<td>50 mL Conical Vial</td>
<td>&nbsp;</td>
<td>BD Falcon</td>
<td>352098</td>
<td>&nbsp;</td>
<tr>
<td>15 mL Conical Vial</td>
<td>&nbsp;</td>
<td>BD Falcon</td>
<td>352099</td>
<td>&nbsp;</td>
<tr>
<td>0.2 &mu;m filter</td>
<td>&nbsp;</td>
<td>Nalgene</td>
<td>194-2520</td>
<td>&nbsp;</td>		</tbody>
		</table>
		</div>

fabrication of myogenic engineered tissue constructs

A pesar de que los marcapasos electrónicos para salvar vidas los dispositivos médicos, su rendimiento a largo plazo en pacientes pediátricos puede ser problemática debido a las restricciones impuestas por el tamaño pequeño de un niño y su crecimiento inevitable. En consecuencia, hay una verdadera necesidad de terapias innovadoras diseñadas específicamente para los pacientes pediátricos con trastornos del ritmo cardíaco. Proponemos que una alternativa conductor biológica que consiste en una matriz a base de colágeno que contiene autologously células derivadas de una mejor podrían adaptarse al crecimiento, reducir la necesidad de cirugías recurrente, y en gran medida a mejorar la calidad de vida de estos pacientes. En el presente estudio, se describe un procedimiento para la incorporación de cultivos primarios de células con mioblastos esqueléticos dentro de una matriz de hidrogel para diseñar una construcción de tejido quirúrgicamente implantable que servirá como un conducto eléctrico entre las cámaras superior e inferior del corazón. En última instancia, esperamos con este tipo de ingeniería tisular para restablecer la conducción eléctrica auriculoventricular en los niños con bloqueo cardíaco completo. En vista de ello, aislamos los mioblastos de músculo esquelético de ratas Lewis neonatal y la placa que en laminina recubierto platos de cultivo de tejidos utilizando una versión modificada de los protocolos establecidos<sup&gt; [2, 3]</sup&gt;. Después de uno o dos días, las células cultivadas se recogen y se mezclan con los antibióticos, el colágeno tipo 1, Matrigel ™, y NaHCO<sub&gt; 3</sub&gt;. El resultado es una solución viscosa, uniforme que se puede convertir en un molde de casi cualquier forma y tamaño<sup&gt; [1, 4, 5]</sup&gt;. Para construcciones de nuestro tejido, empleamos el colágeno tipo 1 aisladas de piel de cordero fetal mediante el procedimiento habitual<sup&gt; [6]</sup&gt;. Una vez que el tejido ha consolidado a 37 ° C, los medios de cultivo se agrega cuidadosamente a la plancha hasta que la construcción se encuentra sumergido. La ingeniería tisular se deja condensar aún más a través de la deshidratación durante 2 días más, momento en el que está listo para<em&gt; In vitro</em&gt; Evaluación o implantación quirúrgica.

Watch this Scientific Journal Video about Fabrication of Myogenic Engineered Tissue Constructs at JoVE.com

Fabrication of Myogenic Engineered Tissue Constructs

Este sentido, demuestran la fabricación de estructuras a base de colágeno del tejido, con mioblastos esqueléticos. Estas construcciones de ingeniería 3-D se puede utilizar para sustituir o reparar los tejidos<em&gt; In vivo</em&gt;. Para nuestros propósitos, hemos diseñado estos como un canal atrioventricular eléctricos para la reparación de un bloqueo cardíaco completo<sup&gt; [1]</sup&gt;.

Fabricación de construcciones de ingeniería tisular miogénica

Despite the fact that electronic pacemakers are life-saving medical devices, their long-term performance in pediatric patients can be problematic owing to ...

fabrication-of-myogenic-engineered-tissue-constructs

Research

JoVE Journal

Biology

10.4K vistas.  Children's Hospital Boston and Harvard Medical School. Este sentido, demuestran la fabricación de estructuras a base de colágeno del tejido, con mioblastos esqueléticos. Estas construcciones de ingeniería 3-D se puede utilizar para sustituir o reparar los tejidos In vivo. Para nuestros propósitos, hemos diseñado estos como un canal atrioventricular eléctricos para la reparación de un bloqueo cardíaco completo [1].

Video: Fabrication of Myogenic Engineered Tissue Constructs

PDMS Device Fabrication and Surface Modification

PDMS fabricación de dispositivos y modificación de la superficie

Investigación

Biología

Fabrication of the Thermoplastic Microfluidic Channels

In our lab, we have successfully isolated nucleic acids directly from microliter and submicroliter volumes of human blood, urine and stool using polymer/nanoparticle composite microscale lysis and solid phase extraction columns. The recovered samples are concentrated, small volume samples that are PCRable, without any additional cleanup. Here, we demonstrate how to fabricate thermoplastic microfluidic chips using hot embossing and heat sealing. Then, we demonstrate how to use in situ light directed surface grafting and polymerization through the sealed chip to form the composite solid phase columns. We demonstrate grafting and polymerization of a carbon nanotube/polymer composite column for bacterial cell lysis. We then show the lysis process followed by solid phase extraction of nucleic acids from the sample on chip using a silica/polymer composite column. The attached protocols contain detailed instructions on how to make both lysis and solid phase extraction columns.

Here we demonstrate how to fabricate thermoplastic microfluidic chips using hot embossing and heat sealing. Then we demonstrate how to use in situ light directed surface grafting and polymerization through the sealed chip to form the composite solid phase columns.

Fabricación de los canales de microfluidos termoplástico

In our lab, we have successfully isolated nucleic acids directly from microliter and submicroliter volumes of human blood, urine and stool using ...

Actin Co-Sedimentation Assay; for the Analysis of Protein Binding to F-Actin

The actin cytoskeleton within the cell is a network of actin filaments that allows the movement of cells and cellular processes, and that generates tension and helps maintains cellular shape.  Although the actin cytoskeleton is a rigid structure, it is a dynamic structure that is constantly remodeling.  A number of proteins can bind to the actin cytoskeleton.  The binding of a particular protein to F-actin is often desired to support cell biological observations or to further understand dynamic processes due to remodeling of the actin cytoskeleton. The actin co-sedimentation assay is an in vitro assay routinely used to analyze the binding of specific proteins or protein domains with F-actin.  The basic principles of the assay involve an incubation of the protein of interest (full length or domain of) with F-actin, ultracentrifugation step to pellet F-actin and analysis of the protein co-sedimenting with F-actin.  Actin co-sedimentation assays can be designed accordingly to measure actin binding affinities and in competition assays.

Proteins bind to filamentous actin (F-actin) through distinct actin binding modules. In this video we demonstrate the procedure of actin co-sedimentation, which is an in vitro assay routinely used to analyze proteins or specific domains that bind F-actin.

Actina Co-sedimentación de ensayo, pues el análisis de proteína de unión a la F-actina

The actin cytoskeleton within the cell is a network of actin filaments that allows the movement of cells and cellular processes, and that generates ...

Fabrication of Amperometric Electrodes

Carbon fiber electrodes are crucial for the detection of catecholamine release from vesicles in single cells for amperometry measurements.  Here, we describe the techniques needed to generate low noise (&lt;0.5 pA) electrodes.  The techniques have been modified from published descriptions by previous researchers (1,2).  Electrodes are made by preparing carbon fibers and threading them individually into each capillary tube by using a vacuum with a filter to aspirate the fiber.  Next, the capillary tube with fiber is pulled by an electrode puller, creating two halves, each with a fine-pointed tip.  The electrodes are dipped in hot, liquid epoxy mixed with hardener to create an epoxy-glass seal.  Lastly, the electrodes are placed in an oven to cure the epoxy.  Careful handling of the electrodes is critical to ensure that they are made consistently and without damage.  This protocol shows how to fabricate and cut amperometric electrodes for recording from single cells.

This protocol describes how to generate carbon fiber electrodes. The electrodes are subsequently used to detect catecholamine release from vesicles with carbon fiber amperometry.

Fabricación de electrodos amperométricos

Carbon fiber electrodes are crucial for the detection of catecholamine release from vesicles in single cells for amperometry measurements.  Here, we ...

Implantation of Engineered Tissue in the Rat Heart

Rodent surgery is often an important component in assessing the utility of engineered tissues. A wide variety of surgical procedures can be performed in common laboratory rats or mice and these quite frequently serve as an intermediate step between bench-top experiments and large animal testing or human trials. Given that rodents provide an established, cost-effective, and physiologically-relevant model system in which to test novel combinations of scaffolding materials and cells, they are particularly well-suited for cardiovascular tissue engineering studies. Presently, we describe an open-heart surgical procedure to implant engineered tissue containing myogenic progenitor cells in the atrioventricular (AV) groove of a rat heart. These implants are intended to create an electrical conduit between the right atrium and right ventricle with the ultimate goal of providing an alternative treatment to conventional pacemaker implantation in pediatric patients with complete heart block[1]. The engineered tissue is implanted in the AV-groove by means of a thoracotomy. For our purposes, Lewis rats are anesthetized and invasively ventilated to maintain positive airway pressure during the sterile surgical procedure. The approach to the heart is performed by a right thoracotomy through an antero-lateral incision at the 5th intercostal space. The tissue construct is fixed in the AV groove using a single 7-0 Prolene suture and positioned between the right ventricle and atrium at the ventral portion of the heart. The epicardium is partially removed to allow direct contact between the recipient myocardial cells and those contained in the engineered tissue. Following implantation, the chest wall is closed in layers, any pneumothorax is evacuated, and the animal is extubated and treated with analgesic.

Here, we describe a cardiac surgical procedure to implant engineered tissue in the atrioventricular (AV)-groove of an adult Lewis rat.

Implantación de la ingeniería tisular en el corazón de rata

Rodent surgery is often an important component in assessing the utility of engineered tissues. A wide variety of surgical procedures can be performed in ...

Mouse Sperm Cryopreservation and Recovery using the I&middot;Cryo Kit

Thousands of new genetically modified (GM) strains of mice have been created since the advent of transgenesis and knockout technologies. Many of these valuable animals exist only as live animals, with no backup plan in case of emergency. Cryopreservation of embryos can provide this backup, but is costly, can be a lengthy procedure, and generally requires a large number of animals for success. Since the discovery that mouse sperm can be successfully cryopreserved with a basic cryoprotective agent (CPA) consisting of 18&#37; raffinose and 3&#37; skim milk, sperm cryopreservation has become an acceptable and cost-effective procedure for archiving, distributing and recovery of these valuable strains.
 Here we demonstrate a newly developed I&bull;Cryo kit for mouse sperm cryopreservation. Sperm from five commonly-used strains of inbred mice were frozen using this kit and then recovered. Higher protection ratios of sperm motility (&gt; 60&#37;) and rapid progressive motility (&gt; 45&#37;) compared to the control (basic CPA) were seen for sperm frozen with this kit in 5 inbred mouse strains. Two cell stage embryo development after IVF with the recovered sperm was improved consistently in all 5 mouse strains examined. Over a 1.5 year period, 49 GM mouse lines were archived by sperm cryopreservation with the I&bull;Cryo kit and later recovered by IVF.

Mouse Sperm Cryopreservation and Recovery using the I&amp;middot;Cryo Kit

Here we demonstrate the newly developed I&#x2022;Cryo kit for mouse sperm cryopreservation. Two-cell stage embryo development with frozen-thawed sperm was improved consistently in 5 mouse strains with the use of this kit. Over a 1.5 year period, 49 genetically modified mouse lines were archived by sperm cryopreservation with the I&#x2022;Cryo kit and later successfully recovered by IVF.

Criopreservación de espermatozoides de ratón y de recuperación con el I · Kit de Cryo

Thousands of new genetically modified (GM) strains of mice have been created since the advent of transgenesis and knockout technologies.  Many of these ...

Recombineering Homologous Recombination Constructs in Drosophila

The continued development of techniques for fast, large-scale manipulation of endogenous gene loci will broaden the use of Drosophila melanogaster as a genetic model organism for human-disease related research. Recent years have seen technical advancements like homologous recombination and recombineering. However, generating unequivocal null mutations or tagging endogenous proteins remains a substantial effort for most genes. Here, we describe and demonstrate techniques for using recombineering-based cloning methods to generate vectors that can be used to target and manipulate endogenous loci in vivo. Specifically, we have established a combination of three technologies: (1) BAC transgenesis/recombineering, (2) ends-out homologous recombination and (3) Gateway technology to provide a robust, efficient and flexible method for manipulating endogenous genomic loci. In this protocol, we provide step-by-step details about how to (1) design individual vectors, (2) how to clone large fragments of genomic DNA into the homologous recombination vector using gap repair, and (3) how to replace or tag genes of interest within these vectors using a second round of recombineering. Finally, we will also provide a protocol for how to mobilize these cassettes in vivo to generate a knockout, or a tagged gene via knock-in. These methods can easily be adopted for multiple targets in parallel and provide a means for manipulating the Drosophila genome in a timely and efficient manner.

Recombineering Homologous Recombination Constructs in Drosophila

Homologous recombination techniques greatly advance Drosophila genetics by enabling the creation of molecularly precise mutations. The recent adoption of recombineering allows one to manipulate large pieces of DNA and transform them into Drosophila6. The methods presented here combine these techniques to rapidly generate large homologous recombination vectors.

Recombinería homólogos Construcciones recombinación en<em&gt; Drosophila</em

The continued development of techniques for fast, large-scale manipulation of endogenous gene loci will broaden the use of Drosophila melanogaster as a ...

Preparation of Primary Myogenic Precursor Cell/Myoblast Cultures from Basal Vertebrate Lineages

Due to the inherent difficulty and time involved with studying the myogenic program in vivo, primary culture systems derived from the resident adult stem cells of skeletal muscle, the myogenic precursor cells (MPCs), have proven indispensible to our understanding of mammalian skeletal muscle development and growth. Particularly among the basal taxa of Vertebrata, however, data are limited describing the molecular mechanisms controlling the self-renewal, proliferation, and differentiation of MPCs. Of particular interest are potential mechanisms that underlie the ability of basal vertebrates to undergo considerable postlarval skeletal myofiber hyperplasia (i.e.&#160;teleost fish) and full regeneration following appendage loss (i.e.&#160;urodele amphibians). Additionally, the use of cultured myoblasts could aid in the understanding of regeneration and the recapitulation of the myogenic program and the differences between them. To this end, we describe in detail a robust and efficient protocol (and variations therein) for isolating and maintaining MPCs and their progeny, myoblasts and immature myotubes, in cell culture as a platform for understanding the evolution of the myogenic program, beginning with the more basal vertebrates. Capitalizing on the model organism status of the zebrafish (Danio rerio), we report on the application of this protocol to small fishes of the cyprinid clade Danioninae. In tandem, this protocol can be utilized to realize a broader comparative approach by isolating MPCs from the Mexican axolotl (Ambystomamexicanum) and even laboratory rodents. This protocol is now widely used in studying myogenesis in several fish species, including rainbow trout, salmon, and sea bream1-4.

In vitro culture systems have proven indispensible to our understanding of vertebrate myogenesis. However, much remains to be learned about nonmammalian skeletal muscle development and growth, particularly in basal taxa. An efficient and robust protocol for isolating the adult stem cells of this tissue, the myogenic precursor cells (MPCs), and maintaining their self-renewal, proliferation, and differentiation in a primary culture setting allows for the identification of conserved and divergent regulatory mechanisms throughout the vertebrate lineages.

Preparación de Primaria Myogenic precursor de célula / cultivos de mioblastos de basales Vertebrados Linajes

Due to the inherent difficulty and time involved with studying the myogenic program in vivo, primary culture systems derived from the resident adult stem ...

Phage-mediated Delivery of Targeted sRNA Constructs to Knock Down Gene Expression in E. coli

RNA-mediated knockdowns are widely used to control gene expression. This versatile family of techniques makes use of short RNA (sRNA) that can be synthesized with any sequence and designed to complement any gene targeted for silencing. Because sRNA constructs can be introduced to many cell types directly or using a variety of vectors, gene expression can be repressed in living cells without laborious genetic modification. The most common RNA knockdown technology, RNA interference (RNAi), makes use of the endogenous RNA-induced silencing complex (RISC) to mediate sequence recognition and cleavage of the target mRNA. Applications of this technique are therefore limited to RISC-expressing organisms, primarily eukaryotes. Recently, a new generation of RNA biotechnologists have developed alternative mechanisms for controlling gene expression through RNA, and so made possible RNA-mediated gene knockdowns in bacteria. Here we describe a method for silencing gene expression in E. coli that functionally resembles RNAi. In this system a synthetic phagemid is designed to express sRNA, which may designed to target any sequence. The expression construct is delivered to a population of E. coli cells with non-lytic M13 phage, after which it is able to stably replicate as a plasmid. Antisense recognition and silencing of the target mRNA is mediated by the Hfq protein, endogenous to E. coli. This protocol includes methods for designing the antisense sRNA, constructing the phagemid vector, packaging the phagemid into M13 bacteriophage, preparing a live cell population for infection, and performing the infection itself. The fluorescent protein mKate2 and the antibiotic resistance gene chloramphenicol acetyltransferase (CAT) are targeted to generate representative data and to quantify knockdown effectiveness.

Phage-mediated Delivery of Targeted sRNA Constructs to Knock Down Gene Expression in E. coli

We describe a method to knock down gene expression in a growing population of E. coli cells using sequence-targeted sRNA expression cassettes delivered by an M13 phagemid vector.

Fagos mediada por la entrega de apuntado sRNA Construye para derribar la expresión génica en<em&gt; E. coli</em

RNA-mediated knockdowns are widely used to control gene expression. This versatile family of techniques makes use of short RNA (sRNA) that can be ...

Dissection of the Auditory Bulla in Postnatal Mice: Isolation of the Middle Ear Bones and Histological Analysis

In most mammals, auditory ossicles in the middle ear, including the malleus, incus and stapes, are the smallest bones. In mice, a bony structure called the auditory bulla houses the ossicles, whereas the auditory capsule encloses the inner ear, namely the cochlea and semicircular canals. Murine ossicles are essential for hearing and thus of great interest to researchers in the field of otolaryngology, but their metabolism, development, and evolution are highly relevant to other fields. Altered bone metabolism can affect hearing function in adult mice, and various gene-deficient mice show changes in morphogenesis of auditory ossicles in utero. Although murine auditory ossicles are tiny, their manipulation is feasible if one understands their anatomical orientation and 3D structure. Here, we describe how to dissect the auditory bulla and capsule of postnatal mice and then isolate individual ossicles by removing part of the bulla. We also discuss how to embed the bulla and capsule in different orientations to generate paraffin or frozen sections suitable for preparation of longitudinal, horizontal, or frontal sections of the malleus. Finally, we enumerate anatomical differences between mouse and human auditory ossicles. These methods would be useful in analyzing pathological, developmental and evolutionary aspects of auditory ossicles and the middle ear in mice.

We present a protocol to isolate the auditory bulla, capsule, and ossicles from postnatal mice for whole mount and histological analysis.

La disección de la Auditivo Bulla en ratones postnatales: Aislamiento de los huesos del oído medio y el análisis histológico

In most mammals, auditory ossicles in the middle ear, including the malleus, incus and stapes, are the smallest bones. In mice, a bony structure called ...