Name: nucleofection and in vivo propagation of chicken eimeria parasites
Uploaded: 2020-02-14T12:00:00
Description: Watch this Scientific Journal Video about Nucleofection and In Vivo Propagation of Chicken Eimeria Parasites at JoVE.com

This work was supported by the National Key Research and Development Program of China (2017YFD0501200) and the National Natural Science Foundation of China (31572507, 31772728 and 31873007).

Chickens for all animal experiments were housed and maintained according to the China Agricultural University Institutional Animal Care and Use Committee guidelines and followed the International Guiding Principles for Biomedical Research Involving Animals. The experiments were approved by the Beijing Administration Committee of Laboratory Animals.
1. Extraction and purification of sporozoites of Eimeria spp. (e.g., E. tenella)
<ol>
	<li>Release of sporocysts
	<ol>
		<li>Ce...

<ol>
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C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Stable+transfection+of+Eimeria+tenella:+Constitutive+expression+of+the+YFP-YFP+molecule+throughout+the+life+cycle.">Stable transfection of Eimeria tenella: Constitutive expression of the YFP-YFP molecule throughout the life cycle.</a> International Journal for Parasitology. 39 (1), 109-117 (2009).</li><li>Qin, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Transfection+of+Eimeria+mitis+with+Yellow+Fluorescent+Protein+as+Reporter+and+the+Endogenous+Development+of+the+Transgenic+Parasite.">Transfection of Eimeria mitis with Yellow Fluorescent Protein as Reporter and the Endogenous Development of the Transgenic Parasite.</a> PloS One. 9 (12), e114188 (2014).</li><li>Duan, C. H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Stable+transfection+of+Eimeria+necatrix+through+nucleofection+of+second+generation+merozoites.">Stable transfection of Eimeria necatrix through nucleofection of second generation merozoites.</a> Molecular and Biochemical Parasitology. , 1-5 (2019).</li><li>Li, Z. R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Transgenic+Eimeria+mitis+expressing+chicken+interleukin+2+stimulated+higher+cellular+immune+response+in+chickens+compared+with+the+wild-type+parasites.">Transgenic Eimeria mitis expressing chicken interleukin 2 stimulated higher cellular immune response in chickens compared with the wild-type parasites.</a> Frontiers in Microbiology. 6, 533 (2015).</li><li>Clark, J. D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Eimeria+species+parasites+as+novel+vaccine+delivery+vectors:+anti-Campylobacter+jejuni+protective+immunity+induced+by+Eimeria+tenella-delivered+CjaA.">Eimeria species parasites as novel vaccine delivery vectors: anti-Campylobacter jejuni protective immunity induced by Eimeria tenella-delivered CjaA.</a> Vaccine. 30 (16), 2683-2688 (2012).</li><li>Eckert, J., Braun, R., Shirley, M. W., Coudert, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Eimeria+species+and+strains+of+chickens.">Eimeria species and strains of chickens.</a> Biotechnology: Guidelines on techniques in coccidiosis research. Part. 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Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Stable+Transfection+of+Eimeria+intestinalis+and+Investigation+of+Its+Life+Cycle,+Reproduction+and+Immunogenicity.">Stable Transfection of Eimeria intestinalis and Investigation of Its Life Cycle, Reproduction and Immunogenicity.</a> Frontiers in Microbiology. 7, 807 (2016).</li><li>Wang, P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+novel+telomerase-interacting+OTU+protein+of+Eimeria+tenella+and+its+telomerase-regulating+activity.">A novel telomerase-interacting OTU protein of Eimeria tenella and its telomerase-regulating activity.</a> Acta Biochimica et Biophysica Sinica. 49 (8), 744-745 (2017).</li><li>Li, J. N., Zou, J., Yin, G. W., Liu, X. 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In the 1990s, a transfection system was developed for apicomplexan parasites, and it was used for studies on eimerian parasites. Recently, stable transfection was conducted in E. tenella8,9 and E. nieschulzi15. We achieved the stable transfection of E. necatrix by transfecting second-generation merozoites11. Inoculation of transfected sporozoites of E. acervulina through the wing ...

Eimeria spp. causes coccidiosis, which leads to substantial economic losses in the livestock and poultry industry. Although anticoccidial drugs, and to an extent, attenuated anticoccidial vaccines, have been used widely for the control of coccidiosis, there are still shortcomings regarding their drug resistance, drug residues, and the potential diffusion of vaccine strains that regain virulence1. With the development of molecular biology, transfection has become a vital tool for studying gene functions, developing novel vaccines, and screening new drug targets for Eimeria.
In the last decades, transfection has been applied successfully for apicomplexan parasites such as Plasmodium and Toxoplasma gondii2,3,4,5,6. A study using &#946;-gal as a reporter for the transfection in E. tenella piloted such work in Eimeria7. The transfection of E. tenella8,9, E. mitis10, and E. acervulina (Zhang et al., unpublished data) was successful in chickens. Recently, we achieved transfection using merozoites of E. necatrix through nucleofection11.
Studies showed that Eimeria expressing a heterologous antigen has the potential to be developed as a recombinant vaccine, such as those expressing Campylobacter jejuni antigen A (CjaA) or chicken interleukin 2 (chIL-2)12,13. Therefore, this protocol describes a nucleofection study of Eimeria spp. in chickens. The procedure describes purification of sporozoites or merozoites, nucleofection with plasmid DNA, cloacal inoculation/intravenous injection and in vivo propagation to help researchers starting studies on transgenic Eimeria parasites.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>ATP-disodium</td>
			<td>Sigma</td>
			<td>A26209</td>
			<td></td>
		</tr>
		<tr>
			<td>Cellulose DE-52</td>
			<td>Solarbio</td>
			<td>C8350</td>
			<td></td>
		</tr>
		<tr>
			<td>Constant Flow Pump</td>
			<td>SHANGHAI JINGKE INDUSTRIAL CO., LTD.</td>
			<td>HL-2B</td>
			<td></td>
		</tr>
		<tr>
			<td>DMEM</td>
			<td>MACGENE</td>
			<td>CM15019</td>
			<td></td>
		</tr>
		<tr>
			<td>Glass beads</td>
			<td>Sigma</td>
			<td>Z250473-1PAK</td>
			<td></td>
		</tr>
		<tr>
			<td>Glucose</td>
			<td>Sigma</td>
			<td>No. V900116</td>
			<td></td>
		</tr>
		<tr>
			<td>Glycine</td>
			<td>Biotopped</td>
			<td>G6200</td>
			<td></td>
		</tr>
		<tr>
			<td>HBSS</td>
			<td>MACGENE</td>
			<td>CC016</td>
			<td></td>
		</tr>
		<tr>
			<td>KH2PO4</td>
			<td>Sigma</td>
			<td>No. V900041</td>
			<td></td>
		</tr>
		<tr>
			<td>Low Speed Centrifuge</td>
			<td>BEIJING ERA BEILI CENTRIFUGE CO., LTD.</td>
			<td>DT5-2</td>
			<td></td>
		</tr>
		<tr>
			<td>Magnetic Mixer</td>
			<td>SCILOGEX</td>
			<td>MS-H280-Pro</td>
			<td></td>
		</tr>
		<tr>
			<td>MgCl2</td>
			<td>Sigma</td>
			<td>449164</td>
			<td></td>
		</tr>
		<tr>
			<td>MoFlo cell sorter</td>
			<td>BeckMan Coulter, US</td>
			<td>201309995</td>
			<td></td>
		</tr>
		<tr>
			<td>NaHCO3</td>
			<td>Sigma</td>
			<td>144-55-8</td>
			<td></td>
		</tr>
		<tr>
			<td>Nucleofection device</td>
			<td>LONZA/amaxa</td>
			<td>90900012 (Nucleofector II)</td>
			<td></td>
		</tr>
		<tr>
			<td>PBS</td>
			<td>Solarbio</td>
			<td>P1010</td>
			<td></td>
		</tr>
		<tr>
			<td>Percoll (DG gradient stock solution)</td>
			<td>GE Healthcare</td>
			<td>17-0891-09</td>
			<td></td>
		</tr>
		<tr>
			<td>Sodium taurodeoxycholate hydrate</td>
			<td>Sigma</td>
			<td>T0875</td>
			<td></td>
		</tr>
		<tr>
			<td>Sorvall Legend Micro 17 Microcentrifuge</td>
			<td>ThermoFisher Scientific</td>
			<td>75002430</td>
			<td></td>
		</tr>
		<tr>
			<td>The composition of DMEM: 4.5 g/L glucose with sodium pyruvate, L-glutamine, and 25 mM HEPES.</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Trypsin</td>
			<td>Solarbio</td>
			<td>T8150</td>
			<td></td>
		</tr>
		<tr>
			<td>Vortex Mixer</td>
			<td>Beijing North TZ-Biotech Develop.co.</td>
			<td>HQ-60-II</td>
			<td></td>
		</tr>
		<tr>
			<td>Water Bath Thermostat</td>
			<td>Grant Instruments (Cambridge), Ltd.</td>
			<td>GD120,GM0815010</td>
			<td></td>
		</tr>
	</tbody>
</table>

nucleofection and in vivo propagation of chicken eimeria parasites

Transfection is a technical process through which genetic material, such as DNA and double-stranded RNA, are delivered into cells to modify the gene of interest. Currently, transgenic technology is becoming an indispensable tool for the study of Eimeria, the causative agents of coccidiosis in poultry and livestock. This protocol provides a detailed description of stable transfection in eimerian parasites: purification and nucleofection of sporozoites or second-generation merozoites, and in vivo propagation of transfected parasites. Using this protocol, we achieved transfection in several species of Eimeria. Taken together, nucleofection is a useful tool to facilitate genetic manipulation in eimerian parasites.

This protocol has been used to transfect eimerian parasites. In this study, the 2nd generation meronts and merozoites of E. necatrix were shown in Figure 2A and Figure 2B, while Figure 2C and Figure 2D showed the sporocysts and sporozoites of E. tenella after using the densit...

Watch this Scientific Journal Video about Nucleofection and In Vivo Propagation of Chicken Eimeria Parasites at JoVE.com

Nucleofection and In Vivo Propagation of Chicken Eimeria Parasites

Here, we provided a method to achieve stable transfection of chicken Eimeria parasites by nucleofecting sporozoites or second-generation merozoites. Genetically modified eimerian parasites expressing heterologous antigenic genes could be used as vaccine delivery vehicles.

Nucleofection and In Vivo Propagation of Chicken Eimeria Parasites

Transfection is a technical process through which genetic material, such as DNA and double-stranded RNA, are delivered into cells to modify the gene of ...

Establishment of transfection protocols for Eimeria species would help to advance the study of gene functions, developing novel vaccines, and screening new drug targets for Eimeria. Using this technique, we achieved the transfection of several species of Eimeria, and nucleofection is a useful tool to facilitate the application of genetic manipulation in eimerian parasites. The nucleofection of Eimeria provides a reference for the transfection of other parasites that can't be cultured in vitro and will accelerate the study of their genetic manipulation.If you try this technique for the first time, you should prepare well all the reagents and their instruments before the start of transfection to avoid scramble during the experiment. The realization of this method helps people who focus on the transfection of Eimeria to see the intricate details of this experiment. To start with release of sporocysts, centrifuge one times 10 to the seven sporulated oocysts in potassium dichromate solution at 2, 300 times g for five minutes.Wash them with PBS three times. Resuspend the pellet with one milliliter of PBS, and transfer the mixture to a 15-milliliter tube. Add an equal volume of one-millimeter-diameter glass beads, and oscillate the oocyst suspension using a vortex mixer to release the sporocysts.Every minute, monitor the release of sporocysts by microscopy. When more than 90%of the oocysts are broken, stop vortexing. Transfer the sporocyst suspension to new 1.5-milliliter tubes, and centrifuge at 1, 600 times g for five minutes.Resuspend the precipitate with one milliliter of 50%density gradient solution, and centrifuge at 10, 000 times g for one minute. To release sporozoites, resuspend the precipitate with excystation buffer, and incubate in a 42-degree Celsius water bath for 40 to 60 minutes to release the sporozoites. Shake the tubes once every five minutes during the excystation.When more than 90%of the sporozoites are released, stop incubating. Centrifuge at 600 times g for 10 minutes. Resuspend the precipitation with one milliliter of 55%density gradient solution, and centrifuge the tube at 10, 000 times g for one minute.Resuspend the precipitation with one milliliter of PBS, and count the sporozoites using a hemocytometer. To collect the second-generation merozoites of Eimeria necatrix, cut the chicken intestine longitudinally from the yolk stalk to the ileocecal orifice, and wash it with PBS or HBSS gently three times in a Petri dish. Cut the intestine into pieces, and place them in a conical flask with a digestion buffer.Place the flask on a magnetic mixer at 37 degrees Celsius with a stirring bar for 30 to 60 minutes to release merozoites. After 30 minutes of incubation, monitor the release of merozoites by microscopic examination every five minutes. To purify the merozoites, pour the suspension containing digested merozoites over four layers of gauze to filter into 50-milliliter tubes, and centrifuge the tubes at 600 times g for 10 minutes.After centrifugation, discard the supernatant containing intestine debris. Transfer the precipitation with purified merozoites to 1.5-milliliter tubes. Resuspend the precipitation with one milliliter of PBS, and count the merozoites using a hemocytometer.First, centrifuge the sporozoite or merozoite suspension at 600 times g for 10 minutes. Then discard the supernatant. In the following order, add 85 microliters of nuclear transfection buffer, 10 micrograms of plasmid, and 25 units of restriction enzyme into the 1.5-milliliter tube containing sporozoites or merozoites.Transfer the suspension to a nuclear transfection cup. Put the cup into a nuclear transfer groove. Turn on the nucleofection device by using the power button, and select the transfection procedure U-033.When the program finishes, press the X button of the nucleofection device, and the screen displays OK, indicating that the nucleofection is successful. Add 0.5 to one milliliters of Dulbecco's Modified Eagle's Medium to the nucleofection cup to stop the reaction. After mixing gently, transfer the suspension to a 1.5-milliliter tube.Inoculate the nucleofected parasites into seven-day-old chickens. Inoculate the merozoites of Eimeria necatrix or the sporozoites of Eimeria tenella via the cloacal route, but inoculate Eimeria acervulina sporozoites via intravenous injection. After collecting oocysts from feces, use fluorescein-activated cell sorting and 150 milligrams per kilogram pyrimethamine to increase the transgenic population ratio.This protocol has been used to transfect eimerian parasites. In this study, the second-generation meronts and merozoites of Eimeria necatrix are shown here, as well as the sporocysts and sporozoites of Eimeria tenella after using the density gradient solutions. The images of the oocysts of Eimeria necatrix after infecting with the nucleofected merozoites and the oocysts of Eimeria tenella after infecting with nucleofected sporozoites indicate successful nucleofection.The most important thing while attempting this procedure is to make sure the purification of sporozoites and merozoites are successful and to use the 50%density gradient solution to remove the OS2 while making sure the sporocysts and the sporozoites are more purified. Following this procedure, you can optimize this protocol, such as transfecting oocyst or sporocyst to simplify the transfection procedures of Eimeria parasites in the future. With the development of transfection in Eimeria, CRISPR-Cas9 technology in Eimeria will be expectable to significantly put forward the cautious genetic manipulation of Eimeria and to be applied as a suitable vaccine delivery vehicle.

nucleofection-and-in-vivo-propagation-of-chicken-eimeria-parasites

Research

JoVE Journal

Biology

Propagation of Human Embryonic Stem (ES) Cells

Propagation of Human Embryonic Stem ES Cells

Windowing Chicken Eggs for Developmental Studies

The study of development has been greatly aided by the use of the chick embryo as an experimental model.  The ease of accessibility of the embryo has allowed for experiments to map cell fates using several approaches, including chick quail chimeras and focal dye labeling.  In addition, it allows for molecular perturbations of several types, including placement of protein-coated beads and introduction of plasmid DNA using in ovo electroporation.  These experiments have yielded important data on the development of the central and peripheral nervous systems.  For many of these studies, it is necessary to open the eggshell and reclose it without perturbing the embryo's growth.  The embryo can be examined at successive developmental stages by re-opening the eggshell.  While there are several excellent methods for opening chicken eggs, in this article we demonstrate one method that has been optimized for long survival times.  In this method, the egg rests on its side and a small window is cut in the shell.  After the experimental procedure, the shell is used to cover the egg for the duration of its development.  Clear plastic tape overlying the eggshell protects the embryo and helps retain hydration during the remainder of the incubation period.  This method has been used beginning at two days of incubation and has allowed survival through mature embryonic ages.

The ease of accessibility of the embryo has allowed for experiments to map cell fates using several approaches, including chick quail chimeras and focal dye labeling. In this article we demonstrate one egg preparation method that has been optimized for long survival times.

The study of development has been greatly aided by the use of the chick embryo as an experimental model.  The ease of accessibility of the embryo has ...

Placing Growth Factor-Coated Beads on Early Stage Chicken Embryos

The neural tube expresses many proteins in specific spatiotemporal patterns during development. These proteins have been shown to be critical for cell fate determination, cell migration, and formation of neural circuits. Neuronal induction and patterning involve bone morphogenetic protein (BMP), sonic hedgehog (SHH), fibroblast growth factor (FGF), among others. In particular, the expression pattern of Fgf8 is in close proximity to regions expressing BMP4 and SHH. This expression pattern is consistent with developmental interactions that facilitate patterning in the telencephalon.

Here we provide a visual demonstration of a method in which an in ovo preparation can be used to test the effects of Fgfs in the formation of the forebrain. Beads are coated with protein and placed in the developing neural tube to provide sustained exposure. Because the procedure uses small, carefully placed beads, it is minimally invasive and allows several beads to be placed within a single neural tube. Moreover, the method allows for continued development so that embryos can be analyzed at a more mature stage to detect changes in anatomy and in neural patterning. This simple but useful protocol allows for real time imaging. It provides a means to make spatially and temporally limited changes to endogenous protein levels.

A variety of growth factors and proteins interact to induce cells to take on different cell fates during development. Here we demonstrate the use of an in ovo preparation to address possible interactions between different proteins in development by placing beads on E2.5 chick embryos.

The neural tube expresses many proteins in specific spatiotemporal patterns during development.   These proteins have been shown to be critical for cell ...

In Ovo Electroporations of HH Stage 10 Chicken Embryos

Large size and external development of the chicken embryo have long made it a valuable tool in the study of developmental biology.  With the advent of molecular biological techniques, the chick has become a useful system in which to study gene regulation and function.  By electroporating DNA or RNA constructs into the developing chicken embryo, genes can be expressed or knocked down in order to analyze in vivo gene function.  Similarly, reporter constructs can be used for fate mapping or to examine putative gene regulatory elements.  Compared to similar experiments in mouse, chick electroporation has the advantages of being quick, easy and inexpensive.  This video demonstrates first how to make a window in the eggshell to manipulate the embryo.  Next, the embryo is visualized with a dilute solution of India ink injected below the embryo.  A glass needle and pipette are used to inject DNA and Fast Green dye into the developing neural tube, then platinum electrodes are placed parallel to the embryo and short electrical pulses are administered with a pulse generator.  Finally, the egg is sealed with tape and placed back into an incubator for further development.  Additionally, the video shows proper egg storage and handling and discusses possible causes of embryo loss following electroporation.

Chick in ovo electroporation is a technique which allows genetic manipulation of the avian embryo. Common applications of this technique include functional analysis of genes and putative enhancer elements. This video demonstrates neural tube electroporation in HH 10 chick embryos. Injection technique and proper egg handling are discussed.

Large size and external development of the chicken embryo have long made it a valuable tool in the study of developmental biology.  With the advent of ...

In vivo and in vitro Studies of Adaptor-clathrin Interaction

A major endocytic pathway initiates with the formation of clathrin-coated vesicles (CCVs) that transport cargo from the cell surface to endosomes1-6. CCVs are distinguished by a polyhedral lattice of clathrin that coats the vesicle membrane and serves as a mechanical scaffold. Clathrin coats are assembled during vesicle formation from individual clathrin triskelia , the soluble form of clathrin composed of three heavy and three light chain subunits7,8. Because the triskelion does not have the ability to bind to the membrane directly, clathrin-binding adaptors are critical to link the forming clathrin lattice to the membrane through association with lipids and/or membrane proteins9. Adaptors also package transmembrane protein cargo, such as receptors, and can interact with each other and with other components of the CCV formation machinery9.
Over twenty clathrin adaptors have been described, several are involved in clathrin mediated endocytosis and others localize to the trans Golgi network or endosomes9. With the exception of HIP1R (yeast Sla2p), all known clathrin adaptors bind to the N-terminal -propeller domain of the clathrin heavy chain9. Clathrin adaptors are modular proteins consisting of folded domains connected by unstructured flexible linkers. Within these linker regions, short binding motifs mediate interactions with the clathrin N-terminal domain or other components of the vesicle formation machinery9. Two distinct clathrin-binding motifs have been defined: the clathrin-box and the W-box9. The consensus clathrin-box sequence was originally defined as L[L/I][D/E/N][L/F][D/E]10 but variants have been subsequently discovered11. The W-box conforms to the sequence PWxxW (where x is any residue).
Sla1p (Synthetic Lethal with Actin binding protein-1) was originally identified as an actin associated protein and is necessary for normal actin cytoskeleton structure and dynamics at endocytic sites in yeast cells12. Sla1p also binds the NPFxD endocytic sorting signal and is critical for endocytosis of cargo bearing the NPFxD signal13,14. More recently, Sla1p was demonstrated to bind clathrin through a motif similar to the clathrin box, LLDLQ, termed a variant clathrin-box (vCB), and to function as an endocytic clathrin adaptor15. In addition, Sla1p has become a widely used marker for the endocytic coat in live cell fluorescence microscopy studies16. Here we use Sla1p as a model to describe approaches for adaptor-clathrin interaction studies. We focus on live cell fluorescence microscopy, GST-pull down, and co-immunoprecipitation methods.

In vivo and in vitro Studies of Adaptor-clathrin Interaction

Clathrin-mediated endocytosis depends on adaptor proteins that coordinate cargo selection and clathrin coat assembly. Here we describe procedures to study adaptor-clathrin physical interaction and live cell imaging approaches using as a model the yeast endocytic adaptor protein Sla1p.

A major endocytic pathway initiates with the formation of clathrin-coated vesicles (CCVs) that transport cargo from the cell surface to endosomes1-6. CCVs ...

Mechanical Stimulation-induced Calcium Wave Propagation in Cell Monolayers: The Example of Bovine Corneal Endothelial Cells

Intercellular communication is essential for the coordination of physiological processes between cells in a variety of organs and tissues, including the brain, liver, retina, cochlea and vasculature. In experimental settings, intercellular Ca2+-waves can be elicited by applying a mechanical stimulus to a single cell. This leads to the release of the intracellular signaling molecules IP3 and Ca2+ that initiate the propagation of the Ca2+-wave concentrically from the mechanically stimulated cell to the neighboring cells. The main molecular pathways that control intercellular Ca2+-wave propagation are provided by gap junction channels through the direct transfer of IP3 and by hemichannels through the release of ATP. Identification and characterization of the properties and regulation of different connexin and pannexin isoforms as gap junction channels and hemichannels are allowed by the quantification of the spread of the intercellular Ca2+-wave, siRNA, and the use of inhibitors of gap junction channels and hemichannels. Here, we describe a method to measure intercellular Ca2+-wave in monolayers of primary corneal endothelial cells loaded with Fluo4-AM in response to a controlled and localized mechanical stimulus provoked by an acute, short-lasting deformation of the cell as a result of touching the cell membrane with a micromanipulator-controlled glass micropipette with a tip diameter of less than 1 &mu;m. We also describe the isolation of primary bovine corneal endothelial cells and its use as model system to assess Cx43-hemichannel activity as the driven force for intercellular Ca2+-waves through the release of ATP. Finally, we discuss the use, advantages, limitations and alternatives of this method in the context of gap junction channel and hemichannel research.

Intercellular Ca2+-waves are driven by gap junction channels and hemichannels. Here, we describe a method to measure intercellular Ca2+-waves in cell monolayers in response to a local single-cell mechanical stimulus and its application to investigate the properties and regulation of gap junction channels and hemichannels.

Intercellular communication is essential for the coordination of physiological processes between cells in a variety of organs and tissues, including the ...

In Vivo Microinjection and Electroporation of Mouse Testis

This video and article contribution gives a comprehensive description of microinjection and electroporation of mouse testis in vivo. This particular transfection technique for testicular mouse cells allows the study of unique processes in spermatogenesis.
The following protocol focuses on transfection of testicular mouse cells with plasmid constructs. Specifically, we used the reporter vector pEGFP-C1, which expresses enhanced green fluorescent protein (eGFP) and also the pDsRed2-N1 vector expressing red fluorescent protein (DsRed2). Both encoded reporter genes were under the control of the human cytomegalovirus immediate-early promoter (CMV).
For performing gene transfer into mouse testes, the reporter plasmid constructs are injected into testes of living mice. To that end, the testis of an anaesthetized animal is exposed and the site of microinjection is prepared. Our preferred place of injection is the efferent duct, with the ultimately connected rete testis as the anatomical transport route of the spermatozoa between the testis and the epididymis. In this way, the filling of the seminiferous tubules after microinjection is excellently managed and controlled due to the use of stained DNA solutions. After observing a sufficient filling of the testis by its colored tubule structure, the organ is electroporated. This enables the transfer of the DNA solution into the testicular&#160;cells. Following 3 days of incubation, the testis is removed and investigated under the microscope for green or red&#160;fluorescence, illustrating transfection success.
Generally, this protocol can be employed for delivering DNA- or RNA- constructs into living mouse testis in order to (over)express or knock down genes, facilitating in vivo gene function analysis. Furthermore, it is suitable for studying reporter constructs or putative gene regulatory elements. Thus, the main advantages of the electroporation technique are fast performance in combination with low effort as well as the moderate technical equipment and skills required compared to alternative techniques.

In Vivo Microinjection and Electroporation of Mouse Testis

This article describes microinjection and electroporation of mouse testis in&#160;vivo as a&#160;transfection technique for testicular mouse cells to study unique processes of spermatogenesis. The presented protocol involves steps of glass capillary preparation, microinjection via the efferent duct, and transfection by electroporation.

This video and article contribution gives a comprehensive description of microinjection and electroporation of mouse testis in vivo. This particular ...

Measuring the Stiffness of Ex Vivo Mouse Aortas Using Atomic Force Microscopy

Arterial stiffening is a significant risk factor and biomarker for cardiovascular disease and a hallmark of aging. Atomic force microscopy (AFM) is a versatile analytical tool for characterizing viscoelastic mechanical properties for a variety of materials ranging from hard (plastic, glass, metal, etc.) surfaces to cells on any substrate. It has been widely used to measure the stiffness of cells, but less frequently used to measure the stiffness of aortas. In this paper, we will describe the procedures for using AFM in contact mode to measure the ex vivo elastic modulus of unloaded mouse arteries. We describe our procedure for isolation of mouse aortas, and then provide detailed information for the AFM analysis. This includes step-by-step instructions for alignment of the laser beam, calibration of the spring constant and deflection sensitivity of the AFM probe, and acquisition of force curves. We also provide a detailed protocol for data analysis of the force curves.

Measuring the Stiffness of Ex Vivo Mouse Aortas Using Atomic Force Microscopy

We present detailed protocols for isolation of aortas from mouse and measurement of their elastic modulus using atomic force microscopy.

Arterial stiffening is a significant risk factor and biomarker for cardiovascular disease and a hallmark of aging. Atomic force microscopy (AFM) is a ...

Preparation and Observation of Thick Biological Samples by Scanning Transmission Electron Tomography

This report describes a protocol for preparing thick biological specimens for further observation using a scanning transmission electron microscope. It also describes an imaging method for studying the 3D structure of thick biological specimens by scanning transmission electron tomography. The sample preparation protocol is based on conventional methods in which the sample is fixed using chemical agents, treated with a heavy atom salt contrasting agent, dehydrated in a series of ethanol baths, and embedded in resin. The specific imaging conditions for observing thick samples by scanning transmission electron microscopy are then described. Sections of the sample are observed using a through-focus method involving the collection of several images at various focal planes. This enables the recovery of in-focus information at various heights throughout the sample. This particular collection pattern is performed at each tilt angle during tomography data collection. A single image is then generated, merging the in-focus information from all the different focal planes. A classic tilt-series dataset is then generated. The advantage of the method is that the tilt-series alignment and reconstruction can be performed using standard tools. The collection of through-focal images allows the reconstruction of a 3D volume that contains all of the structural details of the sample in focus.

This report describes a sample preparation protocol and specific imaging conditions for performing scanning transmission electron tomography of thick biological specimens.

This report describes a protocol for preparing thick biological specimens for further observation using a scanning transmission electron microscope. It ...

Performing In Vivo and Ex Vivo Electrical Impedance Myography in Rodents

Electrical impedance myography (EIM) is a convenient technique that can be used in preclinical and clinical studies to assess muscle tissue health and disease. EIM is obtained by applying a low-intensity, directionally focused, electrical current to a muscle of interest across a range of frequencies (i.e., from 1 kHz to 10 MHz) and recording the resulting voltages. From these, several standard impedance components, including the reactance, resistance, and phase, are obtained. When performing ex vivo measurements on excised muscle, the inherent passive electrical properties of the tissue, namely the conductivity and relative permittivity, can also be calculated. EIM has been used extensively in animals and humans to diagnose and track muscle alterations in a variety of diseases, in relation to simple disuse atrophy, or as a measure of therapeutic intervention. Clinically, EIM offers the potential to track disease progression over time and to assess the impact of therapeutic interventions, thus offering the opportunity to shorten the clinical trial duration and reduce sample size requirements. Because it can be performed noninvasively or minimally invasively in living animal models as well as humans, EIM offers the potential to serve as a novel translational tool enabling both preclinical and clinical development. This article provides step-by-step instructions on how to perform in vivo and ex vivo EIM measurements in mice and rats, including approaches to adapt the techniques to specific conditions, such as for use in pups or obese animals.

Performing In Vivo and Ex Vivo Electrical Impedance Myography in Rodents

This article details how to perform in vivo (using surface and needle electrode arrays) and ex vivo (using a dielectric cell) electrical impedance myography on the rodent gastrocnemius muscle. It will demonstrate the technique in both mice and rats and detail the modifications available, (i.e., obese animals, pups).

Electrical impedance myography (EIM) is a convenient technique that can be used in preclinical and clinical studies to assess muscle tissue health and ...