Damos las gracias al Laboratorio WM Keck Bioimagen para el uso de su estación de trabajo de video microscopía. Este estudio fue financiado por la NSF IBN-0615435 concesión.

<ol>
	<li>Ward, G. E., Brokaw, C. J., Garbers, D. L., Vacquier, V. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chemotaxis+of+Arbacia+punctulata+spermatozoa+to+resact,+a+peptide+from+the+egg+jelly+layer.">Chemotaxis of Arbacia punctulata spermatozoa to resact, a peptide from the egg jelly layer.</a> J. Cell Biol. 101, 2324-2329 (1985).</li><li>Olivera, R. G., Tomasi, L., Rovasio, R. A., Giojalas, L. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Increased+velocity+and+induction+of+chemotactic+response+in+mouse+spermatozoa+by+follicular+and+oviductal+fluids.">Increased velocity and induction of chemotactic response in mouse spermatozoa by follicular and oviductal fluids.</a> J. Reprod. Fertil. 115, 23-27 (1999).</li><li>Fabro, G., Rovasio, R. A., Civalero, S., Frenkel, A., Caplan, S. 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K., Hatt, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Odorant+receptors+and+olfactory-like+signaling+mechanisms+in+mammalian+sperm.Mol.">Odorant receptors and olfactory-like signaling mechanisms in mammalian sperm.Mol.</a> Cell. Endocrinol. 250, 128-136 (2006).</li><li>Veitinger, T., Riffell, J. R., Veitinger, S., Nascimento, J. M., Triller, A., Chandsawangbhuwana, C., Schwane, K., Geerts, A., Wunder, F., Berns, M. W., Neuhaus, E. M., Zimmer, R. K., Spehr, M., Hatt, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chemosensory+Ca2++dynamics+correlate+with+diverse+behavioral+phenotypes+in+human+sperm.">Chemosensory Ca2+ dynamics correlate with diverse behavioral phenotypes in human sperm.</a> J. Biol. Chem. 286, 17311-17325 (2011).</li><li>Tholl, N., Naqvi, S., McLaughlin, E., Boyles, S., Bieber, A. L., Chandler, D. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Swimming+of+Xenopus+laevis+sperm+exhibits+multiple+gears+and+its+duration+is+extended+by+egg+jelly+constituents.">Swimming of Xenopus laevis sperm exhibits multiple gears and its duration is extended by egg jelly constituents.</a> Biol. Bull. 220, 174-185 (2011).</li><li>Eisenbach, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sperm+chemotaxis.">Sperm chemotaxis.</a> Rev. Reprod. 4, 56-66 (1999).</li><li>Riffell, J. A., Zimmer, R. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sex+and+flow:+the+consequences+of+fluid+shear+for+sperm-egg+interactions.">Sex and flow: the consequences of fluid shear for sperm-egg interactions.</a> J. Exp. Biol. 210, 3644-3660 (2007).</li><li>Corkidi, G., Taboada, B., Wood, C. D., Guerrero, A., Darszon, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tracking+sperm+in+three-dimensions.">Tracking sperm in three-dimensions.</a> Biochem. Biophys. Res. Commun. 373, 125-129 (2008).</li><li>Himes, J. E., Riffell, J. A., Zimmer, C. A., Zimmer, R. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sperm+chemotaxis+as+revealed+with+live+and+synthetic+eggs.">Sperm chemotaxis as revealed with live and synthetic eggs.</a> Biol Bull. 220, 1-5 (2011).</li><li>Sun, F., Giojolas, L. C., Rovasio, R. A., Tur-Kaspa, I., Sanchez, R., Eisenbach, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Lack+of+species-specificity+in+mammalian+sperm+chemotaxis.">Lack of species-specificity in mammalian sperm chemotaxis.</a> Dev. Biol. 255, 423-427 (2003).</li><li>Guidobaldi, H. A., Teves, M. E., U&#241;ates, D. R., Anastas&#237;a, A., Giojalas, L. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Progesterone+from+the+cumulus+cells+is+the+sperm+chemoattractant+secreted+by+the+rabbit+oocyte+cumulus+complex.">Progesterone from the cumulus cells is the sperm chemoattractant secreted by the rabbit oocyte cumulus complex.</a> PLoS One. 3, e3040-e3040 (2008).</li><li>Oren-Benaroya, R., Orvieto, R., Gakamsky, A., Pinchasov, M., Eisenbach, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+sperm+chemoattractant+secreted+from+human+cumulus+cells+is+progesterone.">The sperm chemoattractant secreted from human cumulus cells is progesterone.</a> Hum. Reprod. 23, 2339-2345 (2008).</li><li>Teves, M. E., Guidobaldi, H. A., U&#241;ates, D. R., Sanchez, R., Miska, W., Publicover, S. J., Morales Garcia, A. A., Giojalas, L. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Molecular+mechanism+for+human+sperm+chemotaxis+mediated+by+progesterone.">Molecular mechanism for human sperm chemotaxis mediated by progesterone.</a> PLoS One. 4, 8211-82 (2009).</li><li>Blengini, C. S., Teves, M. E., Uñates, D. R., Guidobaldi, H. A., Gatica, L. V., Giojalas, L. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Human+sperm+pattern+of+movement+during+chemotactic+re-orientation+towards+a+progesterone+source.">Human sperm pattern of movement during chemotactic re-orientation towards a progesterone source.</a> Asian J. Androl. 13, 769-773 (2011).</li><li>Strünker, T., Goodwin, N., Brenker, C., Kashikar, N. D., Weyand, I., Seifert, R., Kaupp, U. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+CatSper+channel+mediates+progesterone-induced+Ca2++influx+in+human+sperm.">The CatSper channel mediates progesterone-induced Ca2+ influx in human sperm.</a> Nature. 471, 382-386 (2011).</li><li>Lishko, P. V., Botchkina, I. L., Kirichok, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Progesterone+activates+the+principal+Ca2++channel+of+human+sperm.">Progesterone activates the principal Ca2+ channel of human sperm.</a> Nature. 471, 387-391 (2011).</li><li>Boyden, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+chemotactic+effect+of+mixtures+of+antibody+and+antigen+on+polymorphonuclear+leucocytes.">The chemotactic effect of mixtures of antibody and antigen on polymorphonuclear leucocytes.</a> J. Exp. Med. 115, 453-465 (1962).</li><li>Zigmond, S. H., Lauffenburger, D. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Assays+of+leukocyte+chemotaxis.">Assays of leukocyte chemotaxis.</a> Annu. Rev. Med. 37, 149-155 (1986).</li><li>Villanueva-Diaz, C., Vadillo-Ortega, F., Kably-Ambe, A., Diaz-Pérez, M. A., Krivitzky, S. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Evidence+that+human+follicular+fluid+contains+a+chemoattractant+for+spermatozoa.">Evidence that human follicular fluid contains a chemoattractant for spermatozoa.</a> Fertil. Steril. 54, 1180-1182 (1990).</li><li>Villanueva-Diaz, C., Arizs-Martinez, J., Bermejo-Martinez, L., Vadillo-Ortega, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Progesterone+induces+human+sperm+chemotaxis.">Progesterone induces human sperm chemotaxis.</a> Fertil. Steril. 64, 1183-1188 (1995).</li><li>Olson, J., Xiang, X., Ziegert, T., Kittleson, A., Rawls, A., Bieber, A., Chandler, D. E. A. l. l. u. r. i. n. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=a+21+kD+sperm+chemoattractant+from+Xenopus+egg+jelly,+is+homologous+to+mammalian+sperm-binding+proteins.">a 21 kD sperm chemoattractant from Xenopus egg jelly, is homologous to mammalian sperm-binding proteins.</a> Proc. Natl. Acad. Sci. U.S.A. 98, 11205-11210 (2001).</li></ol>

No hay conflictos de interés declarado.

Quimiotaxis de células en movimiento, ya sea el movimiento ameboide o nadar flagelos potencia se encuentra en muchos contextos biológicos y el estudio de este fenómeno requiere la disponibilidad de ensayos de práctica y confiable. Algunos ejemplos de este fenómeno, como la atracción de los espermatozoides de un huevo de erizo de mar o la recolección de las células de moho del lodo para formar un cuerpo fructífero, tienen un impacto visual inmediato. La cuantificación de este fenómeno ha llevado a cabo en una ...

<table border="1"><tbody><tr><td> Nombre de la pieza </td><td> Empresa </td><td> Número de catálogo </td><td> Comentarios </td></tr><tr><td> Placas de 24 pocillos </td><td> Becton-Dickenson </td><td> 35/1147 </td><td></td></tr><tr><td> 12 inserciones mm de diámetro exterior con una membrana de poro de 12 micras </td><td> Millipore </td><td> PIXP01250 </td><td> Antes utilizábamos Costar, Corning placa Transwell # 3403-ahora suspendido </td></tr><tr><td> Zigmond cámara </td><td> Neurosonda </td><td> Z02 </td><td></td></tr><tr><td> El aceite de silicona </td><td> General Electric </td><td> SF1154 </td><td> Equivalente a Dow Corning de fluidos 550 </td></tr><tr><td> Image J software </td><td> Wayne Rasband, Oficina de Servicios de Investigación, Instituto Nacional de Salud Mental </td><td> Descarga gratuita en http://rsbweb.nih.gov/ij </td><td> De programa de Java que se ejecuta en Windows, LinUX y Mac </td></tr><tr><td> MtrackJ software </td><td> Erik Meijering / Imagescience / <a href="http://www.bigr.nl/">Grupo de Imágenes Biomédicas</a> , Erasmus MC - University Medical Center Rotterdam </td><td> Descarga gratuita en <a href="http://www.imagescience.org/meijering/software/mtrackj/">http://www.imagescience.org/meijering/software/mtrackj/</a> </td><td> De programa de Java que se ejecuta en Windows, Linux y Mac </td></tr><tr><td> Virtual Dub software </td><td> <a href="http://www.virtualdub.org/gpl.html">Licencia Pública General de GNU</a> de software </td><td> Descarga gratis a través <a href="http://www.virtualdub.org/index.html">http://www.virtualdub.org/index.html</a> </td><td> Instrucciones de configuración en la página web de J de la imagen en plugins, sólo para Windows </td></tr><tr><td> cellSens software </td><td> Olimpo </td><td> Véase el sitio web: <a href="http://www.olympusamerica.com/seg_section/product.asp?product=1070">http://www.olympusamerica.com/seg_section/p</a>roduct.asp? producto = 1070 </td><td> Los controles y toma imágenes de una variedad de cámaras. También tiene capacidad de procesamiento de imágenes </td></tr></tbody></table>

two types of assays for detecting frog sperm chemoattraction

Quimioatracción espermatozoides en los invertebrados puede ser lo suficientemente robusta que se puede colocar una pipeta que contiene el péptido atractivo en una suspensión de esperma y microscópicamente visualizar la acumulación de esperma en todo el pipeta de 1. Quimioatracción espermatozoides en los vertebrados como ranas, roedores y seres humanos es más difícil de detectar y requiere ensayos cuantitativos. Estos ensayos son de dos tipos principales - los ensayos que cuantifican el movimiento del esperma a una fuente de quimiotáctica, llamados ensayos de la acumulación de esperma, y ​​los ensayos que en realidad seguimiento de las trayectorias de natación de los espermatozoides individuales. Los ensayos de la acumulación de esperma están permitiendo a decenas o cientos relativamente rápido de los ensayos a realizar en un solo día, lo que permite curvas de dosis-respuesta y los cursos de tiempo para llevar a cabo de forma relativamente rápida. Este tipo de ensayos se han utilizado ampliamente para caracterizar muchos sistemas bien establecidos quimioatracción - por ejemplo, la quimiotaxis de neutrófilos al bacpéptidos terial y la quimiotaxis de espermatozoides al líquido folicular. Los ensayos de los espermatozoides de seguimiento puede ser más mano de obra, pero ofrecen datos adicionales sobre cómo chemoattractancts alteran realmente el camino que los espermatozoides nadar tomar. Este tipo de ensayo es necesaria para demostrar la orientación del movimiento de los espermatozoides con respecto al eje de degradado chemoattrractant y visualizar resulta característica o cambios en la orientación que llevan los espermatozoides más cerca del óvulo. A continuación se describen los métodos utilizados para cada uno de estos dos tipos de ensayos. El ensayo de la acumulación de semen utilizado se llama &quot;doble cámara&quot; ensayo. Espermatozoides de anfibios se encuentran en una inserción de placa de cultivo de tejidos con un piso de filtro de policarbonato con poros de 12 micras de diámetro. Insertos con los espermatozoides se colocan en los pozos de la placa de cultivo de tejido que contiene tampón y un chemoatttractant cuidadosamente pipeta en el fondo del pozo donde el piso y la pared (ver fig. 1). Después de la incubación, el inserto superior que contiene el depósito de los espermatozoides es cuidadosamente removed, y los espermatozoides en la cavidad inferior que han pasado a través de la membrana se eliminan, se sedimentaron y contadas por hemocitómetro o citómetro de flujo. El ensayo de seguimiento de esperma utiliza una cámara Zigmond desarrollado originalmente para la observación de la quimiotaxis de neutrófilos y modificado para la observación de los espermatozoides por Giojalas y compañeros de trabajo 2,3. La cámara se compone de una lámina de vidrio grueso en el que dos canales verticales que se han mecanizado. Estos están separados por una plataforma de observación de 1 mm de ancho. Después de la aplicación de una cubierta de vidrio, los espermatozoides se cargan en un canal, el agente quimiotáctico en el otro y el movimiento de los espermatozoides individuales visualizado por microscopía de vídeo. Las imágenes de vídeo se analiza el uso de software para identificar dos dimensiones los movimientos celulares en el plano xy como una función del tiempo (XYT conjuntos de datos) que forman la trayectoria de cada uno de los espermatozoides.

Watch this Scientific Journal Video about Two Types of Assays for Detecting Frog Sperm Chemoattraction at JoVE.com

Two Types of Assays for Detecting Frog Sperm Chemoattraction

Los huevos y los recubrimientos extracelular alrededor de los huevos con frecuencia liberación péptidos, proteínas y pequeñas moléculas que se comunican con el esperma para guiarlos hacia el óvulo promoviendo así la fecundación. Utilizando el esperma de rana se describen y comparan dos tipos de ensayos para detectar los espermatozoides quimioatracción - ensayos de esperma y la acumulación de pruebas de esperma de seguimiento.

Dos tipos de ensayos para la detección de espermatozoides quimioatracción rana

Sperm chemoattraction in invertebrates can be sufficiently robust that one can place a pipette containing the attractive peptide into a sperm suspension ...

two-types-of-assays-for-detecting-frog-sperm-chemoattraction

Research

JoVE Journal

Biology

19.0K vistas.  University of Illinois, Urbana-Champaign. Los huevos y los recubrimientos extracelular alrededor de los huevos con frecuencia liberación péptidos, proteínas y pequeñas moléculas que se comunican con el esperma para guiarlos hacia el óvulo promoviendo así la fecundación. Utilizando el esperma de rana se describen y comparan dos tipos de ensayos para detectar los espermatozoides quimioatracción - ensayos de esperma y la acumulación de pruebas de esperma de seguimiento.

Video: Two Types of Assays for Detecting Frog Sperm Chemoattraction

Harvesting Sperm and Artificial Insemination of Mice

Rodents of the genus Peromyscus (deer mice) are the most prevalent native North American mammals. Peromyscus species are used in a wide range of research including toxicology, epidemiology, ecology, behavioral, and genetic studies. Here they provide a useful model for demonstrations of artificial insemination. 

Methods similar to those displayed here have previously been used in several deer mouse studies, yet no detailed protocol has been published. Here we demonstrate the basic method of artificial insemination. This method entails extracting the testes from the rodent, then isolating the sperm from the epididymis and vas deferens. The mature sperm, now in a milk mixture, are placed in the female&#x2019;s reproductive tract at the time of ovulation. Fertilization is counted as day 0 for timing of embryo development. Embryos can then be retrieved at the desired time-point and manipulated.

Artificial insemination can be used in a variety of rodent species where exact embryo timing is crucial or hard to obtain. This technique is vital for species or strains (including most Peromyscus) which may not mate immediately and/or where mating is hard to assess. In addition, artificial insemination provides exact timing for embryo development either in mapping developmental progress and/or transgenic work. Reduced numbers of animals can be used since fertilization is guaranteed. This method has been vital to furthering the Peromyscus system, and will hopefully benefit others as well.

This protocol demonstrates methods for extracting sperm from the testes of males and then inseminating female mice. This procedure is useful when precise time is needed in developmental studies as well as transgenic work.

Los espermatozoides de cosecha y la inseminación artificial de los ratones

Rodents of the genus Peromyscus (deer mice) are the most prevalent native North American mammals.  Peromyscus species are used in a wide range of research ...

Investigación

Biología

A High-Throughput Method For Zebrafish Sperm Cryopreservation and In Vitro Fertilization

This is a method for zebrafish sperm cryopreservation that is an adaptation of the Harvey method (Harvey et al., 1982).  We have introduced two changes to the original protocol that both streamline the procedure and increase sample uniformity.  First, we normalize all sperm volumes using freezing media that does not contain the cryoprotectant. Second, cryopreserved sperm are stored in cryovials instead of capillary tubes.  The rates of sperm freezing and thawing (&delta;&deg;C/time) are probably the two most critical variables to control in this procedure.  For this reason, do not substitute different tubes for those specified.  Working in teams of 2 it is possible to freeze the sperm of 100 males per team in ~2 hrs.  Sperm cryopreserved using this protocol has an average of 25% fertility (measured as the number of viable embryos generated in an in vitro fertilization divided by the total number of eggs fertilized) and this percent fertility is stable over many years.

A High-Throughput Method For Zebrafish Sperm Cryopreservation and In Vitro Fertilization

This is a high-throughput sperm cryopreservation protocol for zebrafish. Sperm cryopreserved using this protocol has an average of 25% fertility in subsequent vitro fertilization and is stable over many years.

Un método de alto rendimiento para la crioconservación de esperma de pez cebra y In Vitro Fertilización

This is a method for zebrafish sperm cryopreservation that is an adaptation of the Harvey method (Harvey et al., 1982).  We have introduced two changes to ...

Techniques for Imaging Ca2+ Signaling in Human Sperm

Fluorescence microscopy of cells loaded with fluorescent, Ca2+-sensitive dyes is used for measurement of spatial and temporal aspects of Ca2+ signaling in live cells. Here we describe the method used in our laboratories for loading suspensions of human sperm with Ca2+-reporting dyes and measuring the fluorescence signal during physiological stimulation. Motile cells are isolated by direct swim-up and incubated under capacitating conditions for 0-24 h, depending upon the experiment. The cell-permeant AM (acetoxy methyl ester) ester form of the Ca2+-reporting dye is then added to a cell aliquot and a period of 1 h is allowed for loading of the dye into the cytoplasm. We use visible wavelength dyes to minimize photo-damage to the cells, but this means that ratiometric recording is not possible. Advantages and disadvantages of this approach are discussed. During the loading period cells are introduced into an imaging chamber and allowed to adhere to a poly-D-lysine coated coverslip. At the end of the loading period excess dye and loose cells are removed by connection of the chamber to the perfusion apparatus. The chamber is perfused continuously, stimuli and modified salines are then added to the perfusion header. Experiments are recorded by time-lapse acquisition of fluorescence images and analyzed in detail offline, by manually drawing regions of interest. Data are normalized to pre-stimulus levels such that, for each cell (or part of a cell), a graph showing the Ca2+ response as % change in fluorescence is obtained.

Techniques for Imaging Ca2+ Signaling in Human Sperm

Stimulus-evoked [Ca2+]i signals of individual human sperm are assessed. Motile cells are loaded with Ca2+-sensitive fluorescent dye (AM-ester method) and immobilised in a perfusable chamber. Cells are imaged by time-lapse fluorescence microscopy and stimulated via the perfusing medium. Responses of single cells (or regions) are analysed offline using Excel.

Técnicas de Imagen Ca 2 + Señalización en el esperma humano

Fluorescence microscopy of cells loaded with fluorescent, Ca2+-sensitive dyes is used for measurement of spatial and temporal aspects of Ca2+ signaling in ...

Analysis of Schwann-astrocyte Interactions Using In Vitro Assays

Schwann cells are one of the commonly used cells in repair strategies following spinal cord injuries. Schwann cells are capable of supporting axonal regeneration and sprouting by secreting growth factors 1,2 and providing growth promoting adhesion molecules 3 and extracellular matrix molecules 4. In addition they myelinate the demyelinated axons at the site of injury 5.
However following transplantation, Schwann cells do not migrate from the site of implant and do not intermingle with the host astrocytes 6,7. This results in formation of a sharp boundary between the Schwann cells and astrocytes, creating an obstacle for growing axons trying to exit the graft back into the host tissue proximally and distally. Astrocytes in contact with Schwann cells also undergo hypertrophy and up-regulate the inhibitory molecules 8-13.
In vitro assays have been used to model Schwann cell-astrocyte interactions and have been important in understanding the mechanism underlying the cellular behaviour.
These in vitro assays include boundary assay, where a co-culture is made using two different cells with each cell type occupying different territories with only a small gap separating the two cell fronts. As the cells divide and migrate, the two cellular fronts get closer to each other and finally collide. This allows the behaviour of the two cellular populations to be analyzed at the boundary. Another variation of the same technique is to mix the two cellular populations in culture and over time the two cell types segregate with Schwann cells clumped together as islands in between astrocytes together creating multiple Schwann-astrocyte boundaries.
The second assay used in studying the interaction of two cell types is the migration assay where cellular movement can be tracked on the surface of the other cell type monolayer 14,15. This assay is commonly known as inverted coverslip assay. Schwann cells are cultured on small glass fragments and they are inverted face down onto the surface of astrocyte monolayers and migration is assessed from the edge of coverslip.
Both assays have been instrumental in studying the underlying mechanisms involved in the cellular exclusion and boundary formation. Some of the molecules identified using these techniques include N-Cadherins 15, Chondroitin Sulphate proteoglycans(CSPGs) 16,17, FGF/Heparin 18, Eph/Ephrins19.
This article intends to describe boundary assay and migration assay in stepwise fashion and elucidate the possible technical problems that might occur.

Analysis of Schwann-astrocyte Interactions Using In Vitro Assays

This article intends to describe in stepwise fashion the commonly used in vitro assays used in studying Schwann cell-asrtocyte interactions.

El análisis de Schwann-astrocito interacciones utilizando In Vitro Ensayos

Schwann cells are one of the commonly used cells in repair strategies following spinal cord injuries. Schwann cells are capable of supporting axonal ...

Isolation and In vitro Activation of Caenorhabditis elegans Sperm

Males and hermaphrodites are the two naturally found sexual forms in the nematode C. elegans. The amoeboid sperm are produced by both males and hermaphrodites. In the earlier phase of gametogenesis, the germ cells of hermaphrodites differentiate into limited number of sperm - around 300 - and are stored in a small 'bag' called the spermatheca. Later on, hermaphrodites continually produce oocytes1. In contrast, males produce exclusively sperm throughout their adulthood. The males produce so much sperm that it accounts for &gt;50% of the total cells in a typical adult worm2. Therefore, isolating sperm from males is easier than from that of hermaphrodites.
Only a small proportion of males are naturally generated due to spontaneous non-disjunction of X chromosome3. Crossing hermaphrodites with males or more conveniently, the introduction of mutations to give rise to Him (High Incidence of Males) phenotype are some of strategies through which one can enrich the male population3.
Males can be easily distinguished from hermaphrodites by observing the tail morphology4. Hermaphrodite's tail is pointed, whereas male tail is rounded with mating structures.
Cutting the tail releases vast number of spermatids stored inside the male reproductive tract. Dissection is performed under a stereo microscope using 27 gauge needles. Since spermatids are not physically connected with any other cells, hydraulic pressure expels internal contents of male body, including spermatids2.
Males are directly dissected on a small drop of 'Sperm Medium'. Spermatids are sensitive to alteration in the pH. Hence, HEPES, a compound with good buffering capacity is used in sperm media. Glucose and other salts present in sperm media help maintain osmotic pressure to maintain the integrity of sperm.
Post-meiotic differentiation of spermatids into spermatozoa is termed spermiogenesis or sperm activation. Shakes5, and Nelson6 previously showed that round spermatids can be induced to differentiate into spermatozoa by adding various activating compounds including Pronase E. Here we demonstrate in vitro spermiogenesis of C. elegans spermatids using Pronase E.
Successful spermiogenesis is pre-requisite for fertility and hence the mutants defective in spermiogenesis are sterile. Hitherto several mutants have been shown to be defective specifically in spermiogenesis process7. Abnormality found during in vitro activation of novel Spe (Spermatogenesis defective) mutants would help us discover additional players participating in this event.

Isolation and In vitro Activation of Caenorhabditis elegans Sperm

A protocol for isolating and activating spermatids from male C. elegans is described here. Cutting the posterior end of male releases spermatids. The spermatids can be activated by addition of protease.

El aislamiento y la In vitro La activación de Caenorhabditis elegans El esperma

Males and hermaphrodites are the two naturally found sexual forms in the nematode C. elegans. The amoeboid sperm are produced by both males and ...

Extraction of Tissue Antigens for Functional Assays

Many of the antigen targets of adaptive immune response, recognized by B and T cells, have not been defined 1. This is particularly true in autoimmune diseases and cancer2. Our aim is to investigate the antigens recognized by human T cells in the autoimmune disease type 1 diabetes 1,3,4,5. To analyze human T-cell responses against tissue where the antigens recognized by T cells are not identified we developed a method to extract protein antigens from human tissue in a format that is compatible with functional assays 6. Previously, T-cell responses to unpurified tissue extracts could not be measured because the extraction methods yield a lysate that contained detergents that were toxic to human peripheral blood mononuclear cells. Here we describe a protocol for extracting proteins from human tissues in a format that is not toxic to human T cells. The tissue is homogenized in a mixture of butan-1-ol, acetonitrile and water (BAW). The protein concentration in the tissue extract is measured and a known mass of protein is aliquoted into tubes. After extraction, the organic solvents are removed by lyophilization. Lyophilized tissue extracts can be stored until required. For use in assays of immune function, a suspension of immune cells, in appropriate culture media, can be added directly to the lyophilized extract. Cytokine production and proliferation by PBMC, in response to extracts prepared using this method, were readily measured. Hence, our method allows the rapid preparation of human tissue lysates that can be used as a source of antigens in the analysis of T-cell responses. We suggest that this method will facilitate the analysis of adaptive immune responses to tissues in transplantation, cancer and autoimmunity.

A simple protocol for preparing extracts of human tissue to be used as a source of antigens in functional T-cell assays is described. This method allows T-cell responses to tissue-derived antigens to be measured in vitro.

Extracción de los antígenos tisulares para Ensayos funcionales

Many of the antigen targets of adaptive immune response, recognized by B and T cells, have not been defined 1. This is particularly true in autoimmune ...

Assessing Differences in Sperm Competitive Ability in Drosophila

Competition among conspecific males for fertilizing the ova is one of the mechanisms of sexual selection, i.e. selection that operates on maximizing the number of successful mating events rather than on maximizing survival and viability 1. Sperm competition represents the competition between males after copulating with the same female 2, in which their sperm are coincidental in time and space. This phenomenon has been reported in multiple species of plants and animals 3. For example, wild-caught D. melanogaster females usually contain sperm from 2-3 males 4. The sperm are stored in specialized organs with limited storage capacity, which might lead to the direct competition of the sperm from different males 2,5.
Comparing sperm competitive ability of different males of interest (experimental male types) has been performed through controlled double-mating experiments in the laboratory 6,7. Briefly, a single female is exposed to two different males consecutively, one experimental male and one cross-mating reference male. The same mating scheme is then followed using other experimental male types thus facilitating the indirect comparison of the competitive ability of their sperm through a common reference. The fraction of individuals fathered by the experimental and reference males is identified using markers, which allows one to estimate sperm competitive ability using simple mathematical expressions 7,8. In addition, sperm competitive ability can be estimated in two different scenarios depending on whether the experimental male is second or first to mate (offense and defense assay, respectively) 9, which is assumed to be reflective of different competence attributes.
Here, we describe an approach that helps to interrogate the role of different genetic factors that putatively underlie the phenomenon of sperm competitive ability in D. melanogaster.

Assessing Differences in Sperm Competitive Ability in Drosophila

Differential sperm competitive ability among Drosophila males with distinct genotypes can be ascertained through double-mating experiments. Each of these experiments involves one of the males of interest and a reference male. Readily identifiable markers in the progeny allow inference of the fraction of individuals fathered by each male.

Diferencias Evaluación de Capacidad Competitiva de espermatozoides en<em&gt; Drosophila</em

Competition among conspecific males for fertilizing the ova is one of the mechanisms of sexual selection, i.e. selection that operates on maximizing the ...

Viability Assays for Cells in Culture

Manual cell counts on a microscope are a sensitive means of assessing cellular viability but are time-consuming and therefore expensive. Computerized viability assays are expensive in terms of equipment but can be faster and more objective than manual cell counts. The present report describes the use of three such viability assays. Two of these assays are infrared and one is luminescent. Both infrared assays rely on a 16&#160;bit Odyssey Imager. One infrared assay uses the DRAQ5 stain for nuclei combined with the Sapphire stain for cytosol and is visualized in the 700 nm channel. The other infrared assay, an In-Cell Western, uses antibodies against cytoskeletal proteins (&#945;-tubulin or microtubule associated protein 2) and labels them in the 800 nm channel. The third viability assay is a commonly used luminescent assay for ATP, but we use a quarter of the recommended volume to save on cost. These measurements are all linear and correlate with the number of cells plated, but vary in sensitivity. All three assays circumvent time-consuming microscopy and sample the entire well, thereby reducing sampling error. Finally, all of the assays can easily be completed within one day of the end of the experiment, allowing greater numbers of experiments to be performed within short timeframes. However, they all rely on the assumption that cell numbers remain in proportion to signal strength after treatments, an assumption that is sometimes not met, especially for cellular ATP. Furthermore, if cells increase or decrease in size after treatment, this might affect signal strength without affecting cell number. We conclude that all viability assays, including manual counts, suffer from a number of caveats, but that computerized viability assays are well worth the initial investment. Using all three assays together yields a comprehensive view of cellular structure and function.

Therapeutic compounds are often first examined in vitro with viability assays. Blind cell counts by a human observer can be highly sensitive to small changes in cell number but do not assess function. Computerized viability assays, as described here, can assess both structure and function in an objective manner.

Los ensayos de viabilidad de las células en cultivo

Manual cell counts on a microscope are a sensitive means of assessing cellular viability but are time-consuming and therefore expensive. Computerized ...

Development of an Insert Co-culture System of Two Cellular Types in the Absence of Cell-Cell Contact

The role of secreted soluble factors in the modification of cellular responses is a recurrent theme in the study of all tissues and systems. In an attempt to make straightforward the very complex relationships between the several cellular subtypes that compose multicellular organisms, in vitro techniques have been developed to help researchers acquire a detailed understanding of single cell populations. One of these techniques uses inserts with a permeable membrane allowing secreted soluble factors to diffuse. Thus, a population of cells grown in inserts can be co-cultured in a well or dish containing a different cell type for evaluating cellular changes following paracrine signaling in the absence of cell-cell contact. Such insert co-culture systems offer various advantages over other co-culture techniques, namely bidirectional signaling, conserved cell polarity and population-specific detection of cellular changes. In addition to being utilized in the field of inflammation, cancer, angiogenesis and differentiation, these co-culture systems are of prime importance in the study of the intricate relationships that exist between the different cellular subtypes present in the central nervous system, particularly in the context of neuroinflammation. This article offers general methodological guidelines in order to set up an experiment in order to evaluating cellular changes mediated by secreted soluble factors using an insert co-culture system. Moreover, a specific protocol to measure the neuroinflammatory effects of cytokines secreted by lipopolysaccharide-activated N9 microglia on neuronal PC12 cells will be detailed, offering a concrete understanding of insert co-culture methodology.

In multicellular organisms, secreted soluble factors elicit responses from different cell types as a result of paracrine signaling. Insert co-culture systems offer a simple way to assess the changes mediated by secreted soluble factors in the absence of cell-cell contact.

Desarrollo de un Sistema de inserción Co-cultivo de dos tipos celulares en ausencia de la célula-célula Contacto

The role of secreted soluble factors in the modification of cellular responses is a recurrent theme in the study of all tissues and systems. In an attempt ...

Fish Sperm Assessment Using Software and Cooling Devices

For gamete quality evaluation, there are innovative, rapid, and quantitative techniques that can provide useful data for aquaculture. Computerized systems for sperm analysis were developed to measure several parameters and one of the most commonly measured is the sperm motility.
Initially, this computer technology was designed for mammalian species, although it can also be used for fish sperm analysis. Fish have specific features that can affect sperm assessment such as a short motility time after activation and, in some cases, adaptation to lower temperatures. Thus, it is necessary to modify both software and hardware components to make motility analysis more efficient for fish sperm analysis. For mammalian sperm, the heating plate is used to maintain optimal temperatures of spermatozoa. However, for some fish species, it is advantageous to use a lower temperature to prolong the duration of motility, since the sperm remain active for less than 2 min. Therefore, cooling devices are necessary to refrigerate samples at constant temperature over the time of analysis, including on the optical microscope. This protocol describes the analysis of fish sperm motility using software for sperm analysis and new cooling devices to optimize the results.

The present protocol describes a procedure of fish sperm assessment using computer-assisted sperm analysis and cooling devices. The software gives a rapid, accurate and quantitative analysis of fish sperm quality based on spermatozoa motility, which can be a useful tool in aquaculture to improve reproduction success.

Evaluación del esperma de pescado utilizando Software y equipos de refrigeración

For gamete quality evaluation, there are innovative, rapid, and quantitative techniques that can provide useful data for aquaculture. Computerized systems ...