We thank Jose Noguera for early assistance with cloacal massage, and Jeffrey Kittilson for lab support. This work was supported by a ND EPSCoR FAR0022429 award to BJH. Publication costs were generously supported by the NDSU Department of Biological Sciences.

This protocol involves vertebrate animal subjects and has been approved by the Institutional Animal Care and Use Committee (IACUC) at North Dakota State University.
1. Semen collection from a passerine bird using cloacal massage
NOTE: Cloacal massage is an effective semen collection technique on reproductively active birds only, but can be performed successfully outside of the breeding season in appropriate captive situations. Reproductive activity should be determined for target species prior to using cloacal massage. This technique can be used on wild birds upon capture or on birds held in captivity.
<ol>
	<li>Starting with a male bird, (in breeding condition) bander&#39;s grip in the non-dominant hand, transfer the bird to the dominant hand with its ventral side touching the palm (Figure 1).
	<ol>
		<li>Ensure that the bird&#39;s head is nearest to the lateral edge of the palm. Lightly secure the head and body using the pinky, ring, and middle fingers. This leaves the bird&#39;s vent and tail exposed.</li>
		<li>Leave the bird&#39;s legs loose or lightly restrained using the palm.</li>
	</ol>
	</li>
</ol>
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/55324/55324fig1.jpg" /> 
Figure 1: Grip for cloacal massage.&#160;The bird is secured lightly in the dominant hand with its ventral side touching the palm and head secured by the pinky finger.&#160;<a href="//cloudfront.jove.com/files/ftp_upload/55324/55324fig1large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<ol start="2">
	<li>Place the dominant index finger and thumb on either side of the superior end of the cloaca and lightly pinch the fingers together while applying very slight pressure toward the tail ( Figure 2). The cloaca will evert, exposing the cloacal mucosa (pink interior). 
	&#8203;NOTE: If the bird is not currently producing semen, the cloacal protuberance can be small and the cloaca is difficult to evert. With experience, it is easy to differentiate between the cloacas of reproductively active and inactive males5,11.</li>
</ol>
<img alt="Figure 2" class="xfigimg" src="/files/ftp_upload/55324/55324fig2.jpg" /> 
Figure 2: Finger position and cloacal protuberance.&#160;Evert the cloaca by applying slight pressure to the superior end (A). In a reproductively active male passerine, the cloacal protuberance is obvious and firm (B).&#160;<a href="//cloudfront.jove.com/files/ftp_upload/55324/55324fig2large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<ol start="3">
	<li>With the non-dominant hand, place the pad of the index finger on the dorsal side of the base of the tail to stabilize the hand, and then place the tip of the thumb just below the everted cloaca. 
	NOTE: A short and smooth thumbnail is advantageous for performing cloacal massage and protects the bird from accidental injury.</li>
	<li>Move the non-dominant thumb deep and cranially in a repetitive motion with medium pressure, staying below the cloaca. Continue until the bird ejaculates. Depending on the individual, this typically takes between 1 and several dozen strokes.</li>
	<li>As soon as the bird ejaculates, collect the semen in a microhematocrit tube. Repeat cloacal massage to obtain multiple ejaculates. 
	&#8203;NOTE: Passerine semen is light brown and typically has a somewhat thick consistency. White or dark substances ejected from the cloaca are not semen, and may contaminate the semen sample. The appearance of a small amount of blood on the cloaca or mixed in with the semen is usually caused by too much pressure during massage.</li>
	<li>For DNA extraction, place the semen into a microcentrifuge tube with 20 &#181;L of 1x PBS (pH 7.4). NOTE: Semen stored in 1x PBS is not suitable for artificial insemination, but can be used for DNA extraction at a later date when stored at -80 &#176;C. The PBS can be room temperature or chilled, but should be in a liquid state when the semen sample is deposited.
	<ol>
		<li>Confirm the presence of sperm in the sample by viewing a small amount of the diluted sample under a compound microscope (Figure 3).</li>
	</ol>
	</li>
	<li>Store the diluted semen at -80 &#176;C until extraction.</li>
</ol>
2. Extraction of DNA from bird semen
NOTE: This protocol has been tested with multiple commercial DNA extraction kits, but it has only been successful when used with one DNA kit12. Steps that are modified from the kit protocol are indicated by *.
<ol>
	<li>Prepare a 1 M solution of dithiothreitol (DTT) in water and mix using a vortex.*
	<ol>
		<li>Aliquot the DTT solution and store it at -20 &#176;C until immediately before use. Each sample to be extracted requires 10 &#181;L of 1 M DTT solution.*</li>
	</ol>
	</li>
	<li>Prepare a buffer containing 20 mM Tris-Cl, pH 8.0; 20 mM EDTA; 200 mM NaCL; and 4% SDS. Each sample to be extracted requires 90 &#181;L of this buffer.*
	<ol>
		<li>Store the buffer at room temperature. If it has precipitated, warm it to 56 &#176;C to dissolve.*</li>
	</ol>
	</li>
	<li>Preheat an incubator containing a rocker or shaker to 65 &#176;C.*</li>
	<li>Immediately before beginning the extraction, mix 10 &#181;L DTT solution with 90 &#181;L of the buffer prepared in step 2.2 for each sample to be extracted, e.g. 900 &#181;L buffer plus 100 &#181;L DTT solution if extracting 10 samples. This mixture will be called DTT-buffer.*</li>
	<li>Add 70 &#181;L 1x&#160;PBS to the entire diluted semen sample and mix well using a vortex.*</li>
	<li>Add 100 &#181;L DTT-buffer and 10 &#181;L proteinase K solution to the sample. Vortex for 20 seconds, then incubate in the preheated incubator for 1 hour on a rocker or shaker.*</li>
	<li>Add 200 &#181;L buffer AL and 200 &#181;L fresh EtOH (100%) and vortex for 20 seconds.*</li>
	<li>Transfer the entire sample to a spin column and centrifuge 1 minute at 6,000 x g. Discard the collection tube.</li>
	<li>Place the column on a new tube and add 500 &#181;L prepared buffer AW1. Centrifuge 1 minute at 6,000 x g. Discard the collection tube.</li>
	<li>Place the column on a new tube and add 500 &#181;L prepared buffer AW2. Centrifuge for 1 minute at 6,000 x g. Discard the flow-through and place the column back on the tube.</li>
	<li>Centrifuge 3 minutes at 20,000 x g. Discard the collection tube and place the column on a 1.5 mL microcentrifuge tube.</li>
	<li>Pipet 35 &#181;L of AE buffer directly onto the column membrane and incubate at room temperature for 5 minutes.*</li>
	<li>Centrifuge 1 minute at 14,000 x g. Discard the spin column and store extracted samples at -80 &#176;C.</li>
</ol>

<ol>
	<li>Briskie, J. V., Montgomerie, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sperm+size+and+sperm+competition+in+birds.">Sperm size and sperm competition in birds.</a> Proc. R. Soc. B. 247, 89-95 (1992).</li><li>Monaghan, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Telomeres+and+life+histories:+the+long+and+the+short+of+it.">Telomeres and life histories: the long and the short of it.</a> Ann. N.Y. Acad. Sci. 1206, 130-142 (2010).</li><li>Carrell, D. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Epigenetics+of+the+male+gamete.">Epigenetics of the male gamete.</a> Fertility and Sterility. 97 (2), 267-274 (2012).</li><li>Burrows, W. H., Quinn, J. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+collection+of+spermatozoa+from+the+domestic+fowl+and+turkey.">The collection of spermatozoa from the domestic fowl and turkey.</a> Poultry Science. 16 (1), 19-24 (1937).</li><li>Wolfson, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+cloacal+protuberance:+a+means+for+determining+breeding+condition+in+live+male+birds.">The cloacal protuberance: a means for determining breeding condition in live male birds.</a> Bird-Banding. 23 (4), 159-165 (1952).</li><li>Kast, T. L., Ketterson, E. D., Nolan, V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Variation+in+ejaculate+quality+in+dark-eyed+juncos+according+to+season,+stage+of+reproduction,+and+testosterone+treatment.">Variation in ejaculate quality in dark-eyed juncos according to season, stage of reproduction, and testosterone treatment.</a> The Auk. 115 (3), 684-693 (1998).</li><li>Helfenstein, F., Podevin, M., Richner, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sperm+morphology,+swimming+velocity,+and+longevity+in+the+house+sparrow+Passer+domesticus.">Sperm morphology, swimming velocity, and longevity in the house sparrow Passer domesticus.</a> Behav. Ecol. Sociobiol. 64, 557-565 (2010).</li><li>Purchase, C. F., Earle, P. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Modifications+to+the+IMAGEJ+computer+assisted+sperm+analysis+plugin+greatly+improve+efficiency+and+fundamentally+alter+the+scope+of+attainable+data.">Modifications to the IMAGEJ computer assisted sperm analysis plugin greatly improve efficiency and fundamentally alter the scope of attainable data.</a> J. Appl. Icthyol. 28, 1013-1016 (2012).</li><li>Gill, P., Jeffreys, A. J., Werrett, D. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Forensic+application+of+DNA+'fingerprints'.">Forensic application of DNA 'fingerprints'.</a> Nature. 318 (12), 577-579 (1985).</li><li>Criscuolo, F., 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=Real-time+quantitative+PCR+assay+for+measurement+of+avian+telomeres.">Real-time quantitative PCR assay for measurement of avian telomeres.</a> J. Avian Biol. 40, 342-347 (2009).</li><li>Lovette, I. J., Fitzpatrick, J. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Cornell Lab of Ornithology Handbook of Bird Biology, 3rd Edition. , (2016).</li><li>. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> QIAamp DNA Micro Handbook. , (2014).</li><li>Carter, K. L., Robertson, B. C., Kempenaers, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+differential+DNA+extraction+method+for+sperm+on+the+perivitelline+membrane+of+avian+eggs.">A differential DNA extraction method for sperm on the perivitelline membrane of avian eggs.</a> Mol. Ecol. 9, 2149-2154 (2000).</li><li>Birkhead, T. R., Buchanan, K. L., Devoogd, T. J., Pellatt, E. J., Catchpole, C. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Song,+sperm+quality+and+testes+asymmetry+in+the+sedge+warbler.">Song, sperm quality and testes asymmetry in the sedge warbler.</a> Anim. Behav. 53, 965-971 (1997).</li><li>L&#252;pold, S., Calhim, S., Immler, S., Birkhead, T. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sperm+morphology+and+sperm+velocity+in+passerine+birds.">Sperm morphology and sperm velocity in passerine birds.</a> Proc. R. Soc. B. 276, 1175-1181 (2009).</li><li>Samour, J. H., Smith, C. A., Moore, H. D., Markham, J. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Semen+collection+and+spermatozoa+characteristics+in+budgerigars+(Melopsittacus+undulates).">Semen collection and spermatozoa characteristics in budgerigars (Melopsittacus undulates).</a> Vet. Rec. 118, 397-399 (1986).</li><li>Stelzer, G., Crosta, L., B&#252;rkle, M., Krautwalt-Junghanns, M. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Attempted+semen+collection+using+the+massage+technique+and+semen+analysis+in+various+psittacine+species.">Attempted semen collection using the massage technique and semen analysis in various psittacine species.</a> J. Avian Med. Surg. 19 (1), 7-13 (2005).</li></ol>

The authors declare that they have no competing financial interests.

We describe a simple and reliable method for collecting semen from small and medium birds in reproductively active condition, and extracting DNA from avian sperm.
The described semen DNA extraction protocol is modified from a kit for simplicity, but was refined for use on avian semen. Sperm are resistant to lysis by standard extraction chemicals9,13, and semen samples collected from passerines are fairly small (typically a few microlit...

Birds are ideal subjects for studies involving sperm quality and competition1, sperm telomere dynamics2, epigenetics3, and similar topics, as they are widely used in biological research and sperm can be easily sampled using cloacal massage. Cloacal massage is a gentle, non-invasive manual technique for collecting semen from birds4,5,6. Repeated samples can be obtained easily and no special tools are required, making it simple to perform in the field or lab. Although cloacal massage has been in use for decades, it is difficult to learn from the available written descriptions. This publication is intended to reduce the time and uncertainty involved in learning cloacal massage.
Semen collected from birds using cloacal massage can be used immediately for motility assessment4,7 or artificial insemination8, or frozen for other uses such as advanced imaging and DNA extraction. Semen samples from passerine birds are small but contain densely packed sperm. DNA is extracted using a commercial extraction kit for simplicity, with modifications to overcome the specialized protective features of sperm9. After extraction, sperm telomeres can be measured using qPCR10.

<table border="0" cellpadding="0" cellspacing="0" style="width:572px;" width="573">
	<colgroup>
		<col />
		<col />
		<col />
		<col />
	</colgroup>
	<tbody>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Microhematocrit capillary tubes</td>
			<td style="width:71px;">Fisherbrand</td>
			<td style="width:119px;">22-362566</td>
			<td style="width:167px;">Any supplier can be used. Smaller tubes may be more effective for collection of small semen samples, such as from very small passerine birds like chipping sparrow.</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Microcentrifuge tubes</td>
			<td style="width:71px;">Any</td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">1x PBS</td>
			<td style="width:71px;">Any</td>
			<td style="width:119px;"></td>
			<td>Used for storing semen samples prior to DNA extraction.</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">DL-Dithiothreitol</td>
			<td style="width:71px;">Sigma-Aldrich</td>
			<td style="width:119px;">D0632</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Tris base</td>
			<td style="width:71px;">Sigma-Aldrich</td>
			<td align="right" style="width:119px;">10708976001</td>
			<td>Any supplier can be used.</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">EDTA</td>
			<td style="width:71px;">Sigma-Aldrich</td>
			<td align="right" style="width:119px;">1233508</td>
			<td>Any supplier can be used.</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">NaCl</td>
			<td style="width:71px;">Sigma-Aldrich</td>
			<td align="right" style="width:119px;">793566</td>
			<td>Any supplier can be used.</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">SDS</td>
			<td style="width:71px;">Sigma-Aldrich</td>
			<td align="right" style="width:119px;">1614363</td>
			<td>Any supplier can be used.</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">QIAamp DNA micro kit</td>
			<td style="width:71px;">Qiagen</td>
			<td align="right" style="width:119px;">56304</td>
			<td>Qiagen QIAamp DNA micro kit is recommended specifically. This DNA extraction protocol has been attempted with other commercial kits but with little success. The reasons for this are unknown to us.&#160;</td>
		</tr>
	</tbody>
</table>

avian semen collection by cloacal massage and isolation of dna from sperm

Collection of semen may be useful for a wide range of applications including studies involving sperm quality, sperm telomere dynamics, and epigenetics. Birds are widely used subjects in biological research and are ideal for studies involving repeated sperm samples. However, few resources are currently available for those wishing to learn how to collect and extract DNA from avian sperm. Here we describe cloacal massage, a gentle, non-invasive manual technique for collecting avian sperm. Although this technique is established in the literature, it can be difficult to learn from the available descriptions. We also provide information for extracting DNA from avian semen using a commercial extraction kit with modifications. Cloacal massage can be easily used on any small- to medium-sized male bird in reproductive condition. Following collection, the semen can be used immediately for motility assays, or frozen for DNA extraction following the protocol described herein. This extraction protocol was refined for avian sperm and has been successfully used on samples collected from several passerine species (Passer domesticus, Spizella passerina, Haemorhous mexicanus, and Turdus migratorius) and one columbid (Columba livia).

Cloacal massage and DNA extraction using the described protocol has been performed on several passerine species and one columbid (Table 1). The presence of sperm in semen samples collected by cloacal massage was confirmed by viewing a small amount of the diluted samples under a compound microscope at 400X&#160;magnification (Figure 3). After extracting DNA from semen samples collected from house sparrows using the protocol described here, eig...

Watch this Scientific Journal Video about Avian Semen Collection by Cloacal Massage and Isolation of DNA from Sperm at JoVE.com

Avian Semen Collection by Cloacal Massage and Isolation of DNA from Sperm

This protocol describes cloacal massage, a non-invasive manual technique for collecting semen from birds, and DNA extraction from avian sperm using a commercial extraction kit with modifications.

Collection of semen may be useful for a wide range of applications including studies involving sperm quality, sperm telomere dynamics, and epigenetics. ...

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15.8K Views.  North Dakota State University. This protocol describes cloacal massage, a non-invasive manual technique for collecting semen from birds, and DNA extraction from avian sperm using a commercial extraction kit with modifications.

Video: Avian Semen Collection by Cloacal Massage and Isolation of DNA from Sperm

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.

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 ...

Isolation of Genomic DNA from Mouse Tails

Human Pancreatic Islet Isolation: Part I: Digestion and Collection of Pancreatic Tissue

Management of Type 1 diabetes is burdensome, both to the individual and society, costing over 100 billion dollars annually. Despite the widespread use of glucose monitoring and new insulin formulations, many individuals still develop devastating secondary complications. Pancreatic islet transplantation can restore near normal glucose control in diabetic patients 1, without the risk of serious hypoglycemic episodes that are associated with intensive insulin therapy. Providing sufficient islet mass is important for successful islet transplantation. However, donor characteristic, organ procurement and preservation affect the isolation outcome 2. At University of Illinois at Chicago (UIC) we have developed a successful isolation protocol with an improved purification gradient 3. The program started in January 2004, and more than 300 isolations were performed up to November 2008. The pancreata were sent in cold preservation solutions (UW, University of Wisconsin or HTK, Histidine-Tryptophan Ketoglutarate) 4-7 to the Cell Isolation Laboratory at UIC for islet isolation. Pancreatic islets were isolated using the UIC method, which is a modified version of the method originally described by Ricordi et al 8. Briefly, after cleaning the pancreas from the surrounding tissue, it was perfused with enzyme solution (Serva Collagenase + Neutral Protease or Sigma V enzyme). The distended pancreas was then transferred to the Ricordi digestion chamber, connected to a modified, closed circulation tubing system, and warmed up to 37&deg;C. During the digestion, the chamber was shaken gently. Samples were taken continuously to monitor the digestion progress. Once free islets were detected under the microscope, the digestion was stopped by flushing cold (4&deg;C) RPMI dilution solution (Mediatech, Herndon, VA) into the circulation system to dilute the enzyme. After being collected and washed in M199 media supplemented with human albumin, the tissue was sampled for pre-purification count and incubated with UW solution before purification. Purification process will be described in Part II: Purification and Culture of Human Islets.

Achieving high quality and appropriate quantity of human islets is one of the prominent prerequisites for successful islet transplantation. In this video, we describe step by step the procedures for human pancreatic islet isolation (part I: digestion and collection of pancreatic tissue) using a modified automated method.

Management of Type 1 diabetes is burdensome, both to the individual and society, costing over 100 billion dollars annually. Despite the widespread use of ...

Isolation and Culture of Avian Embryonic Valvular Progenitor Cells

Proper formation and function of embryonic heart valves is critical for developmental progression. The early embryonic heart is a U-shaped tube of endocardium surrounded by myocardium. The myocardium secretes cardiac jelly, a hyaluronan-rich gelatinous matrix, into the atrioventricular (AV) junction and outflow tract (OFT) lumen. At stage HH14 valvulogenesis begins when a subset of endocardial cells receive signals from the myocardium, undergo endocardial to mesenchymal transformation (EMT), and invade the cardiac jelly. At stage HH25 the valvular cushions are fully mesenchymalized, and it is this mesenchyme that eventually forms the valvular and septal apparatus of the heart. Understanding the mechanisms that initiate and modulate the process of EMT and cell differentiation are important because of their connection to serious congenital heart defects. In this study we present methods to isolate pre-EMT endocardial and post-EMT mesenchymal cells, which are the two different cell phenotypes of the prevalvular cushion. Pre-EMT endocardial cells can be cultured with or without the myocardium. Post-EMT AV cushion mesenchymal cells can be cultured inside mechanically constrained or stress-free collagen gels. These 3D in vitro models mimic key valvular morphogenic events and are useful for deconstructing the mechanisms of early and late stage valvulogenesis.

This article will provide a method for isolating and culturing quail or chicken HH14- valve endocardial cells and HH25 valve cushion mesenchymal cells.

Proper formation and function of embryonic heart valves is critical for developmental progression. The early embryonic heart is a U-shaped tube of ...

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.

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

A Practical and Novel Method to Extract Genomic DNA from Blood Collection Kits for Plasma Protein Preservation

Laboratory tests can be done on the cellular or fluid portions of the blood. The use of different blood collection tubes determines the portion of the blood that can be analyzed (whole blood, plasma or serum). Laboratories involved in studying the genetic basis of human disorders rely on anticoagulated whole blood collected in EDTA-containing vacutainer as the source of DNA for genetic / genomic analysis. Because most clinical laboratories perform biochemical, serologic and viral testing as a first step in phenotypic outcome investigation, anticoagulated blood is also collected in heparin-containing tube (plasma tube). Therefore when DNA and plasma are needed for simultaneous and parallel analyses of both genomic and proteomic data, it is customary to collect blood in both EDTA and heparin tubes. If blood could be collected in a single tube and serve as a source for both plasma and DNA, that method would be considered an advancement to existing methods. The use of the compacted blood after plasma extraction represents an alternative source for genomic DNA, thus minimizing the amount of blood samples processed and reducing the number of samples required from each patient. This would ultimately save time and resources.
The BD P100 blood collection system for plasma protein preservation were created as an improved method over previous plasma or serum collection tubes1, to stabilize the protein content of blood, enabling better protein biomarker discovery and proteomics experimentation from human blood. The BD P100 tubes contain 15.8 ml of spray-dried K2EDTA and a lyophilized proprietary broad spectrum cocktail of protease inhibitors to prevent coagulation and stabilize the plasma proteins. They also include a mechanical separator, which provides a physical barrier between plasma and cell pellets after centrifugation. Few methods have been devised to extract DNA from clotted blood samples collected in old plasma tubes2-4. Challenges from these methods were mainly associated with the type of separator inside the tubes (gel separator) and included difficulty in recovering the clotted blood, the inconvenience of fragmenting or dispersing the clot, and obstruction of the clot extraction by the separation gel.
We present the first method that extracts and purifies genomic DNA from blood drawn in the new BD P100 tubes. We compare the quality of the DNA sample from P100 tubes to that from EDTA tubes. Our approach is simple and efficient. It involves four major steps as follows: 1) the use of a plasma BD P100 (BD Diagnostics, Sparks, MD, USA) tube with mechanical separator for blood collection, 2) the removal of the mechanical separator using a combination of sucrose and a sterile paperclip metallic hook, 3) the separation of the buffy coat layer containing the white cells and 4) the isolation of the genomic DNA from the buffy coat using a regular commercial DNA extraction kit or a similar standard protocol.

We are describing a new method of isolating genomic DNA from whole blood collected for plasma/serology. After plasma collection, the compacted blood is usually discarded. Our novel method represents a significant improvement over existing methods and makes DNA and plasma available from a single collection, without requesting additional blood.

Laboratory tests can be done on the cellular or  fluid portions of the blood. The use of different blood collection tubes  determines the portion of the ...

Collection, Isolation and Enrichment of Naturally Occurring Magnetotactic Bacteria from the Environment

Magnetotactic bacteria (MTB) are aquatic microorganisms that were first notably described in 19751 from sediment samples collected in salt marshes of Massachusetts (USA). Since then MTB have been discovered in stratified water- and sediment-columns from all over the world2. One feature common to all MTB is that they contain magnetosomes, which are intracellular, membrane-bound magnetic nanocrystals of magnetite (Fe3O4) and/or greigite (Fe3S4) or both3, 4. In the Northern hemisphere, MTB are typically attracted to the south end of a bar magnet, while in the Southern hemisphere they are usually attracted to the north end of a magnet3,5. This property can be exploited when trying to isolate MTB from environmental samples.
One of the most common ways to enrich MTB is to use a clear plastic container to collect sediment and water from a natural source, such as a freshwater pond. In the Northern hemisphere, the south end of a bar magnet is placed against the outside of the container just above the sediment at the sediment-water interface. After some time, the bacteria can be removed from the inside of the container near the magnet with a pipette and then enriched further by using a capillary racetrack6 and a magnet. Once enriched, the bacteria can be placed on a microscope slide using a hanging drop method and observed in a light microscope or deposited onto a copper grid and observed using transmission electron microscopy (TEM).
Using this method, isolated MTB may be studied microscopically to determine characteristics such as swimming behavior, type and number of flagella, cell morphology of the cells, shape of the magnetic crystals, number of magnetosomes, number of magnetosome chains in each cell, composition of the nanomineral crystals, and presence of intracellular vacuoles.

We demonstrate a method to collect magnetotactic bacteria (MTB) that can be applied to natural waters. MTB can be isolated and enriched from sediment samples using a relatively simple setup that takes advantage of the bacteria's natural magnetism. Isolated MTB can then be examined in detail using both light and electron microscopy.

Magnetotactic bacteria (MTB) are aquatic microorganisms that were first notably described in 19751 from sediment samples collected in salt marshes of ...

Utero-tubal Embryo Transfer and Vasectomy in the Mouse Model

The transfer of preimplantation embryos to a surrogate female is a required step for the production of genetically modified mice or to study the effects of epigenetic alterations originated during preimplantation development on subsequent fetal development and adult health. The use of an effective and consistent embryo transfer technique is crucial to enhance the generation of genetically modified animals and to determine the effect of different treatments on implantation rates and survival to term. Embryos at the blastocyst stage are usually transferred by uterine transfer, performing a puncture in the uterine wall to introduce the embryo manipulation pipette. The orifice performed in the uterus does not close after the pipette has been withdrawn, and the embryos can outflow to the abdominal cavity due to the positive pressure of the uterus. The puncture can also produce a hemorrhage that impairs implantation, blocks the transfer pipette and may affect embryo development, especially when embryos without zona are transferred. Consequently, this technique often results in very variable and overall low embryo survival rates. Avoiding these negative effects, utero-tubal embryo transfer take advantage of the utero-tubal junction as a natural barrier that impedes embryo outflow and avoid the puncture of the uterine wall. Vasectomized males are required for obtaining pseudopregnant recipients. A technique to perform vasectomy is described as a complement to the utero-tubal embryo transfer.

Utero-tubal embryo transfer uses the utero-tubal junction as a barrier to prevent the embryo outflow that may occur when performing uterine transfer. Vasectomized males are required to obtain pseudopregnant recipients for embryo transfer. Both techniques are discussed.

The transfer of preimplantation embryos to a surrogate female is a required step for the production of genetically modified mice or to study the effects ...

Culturing Caenorhabditis elegans in Axenic Liquid Media and Creation of Transgenic Worms by Microparticle Bombardment

In this protocol, we present the required materials, and the procedure for making modified&#160;C. elegans&#160;Habituation and Reproduction media (mCeHR). Additionally, the steps for exposing and acclimatizing C. elegans grown on E. coli to axenic liquid media are described. Finally, downstream experiments that utilize axenic C. elegans illustrate the benefits of this procedure. The ability to analyze and determine C. elegans&#160;nutrient requirement was illustrated by growing N2 wild type worms in axenic liquid media with varying heme concentrations. This procedure can be replicated with other nutrients to determine the optimal concentration for worm growth and development or, to determine the toxicological effects of drug treatments. The effects of varied heme concentrations on the growth of wild type worms were determined through qualitative microscopic observation and by quantitating the number of worms that grew in each heme concentration. In addition, the effect of varied nutrient concentrations can be assayed by utilizing worms that express fluorescent sensors that respond to changes in the nutrient of interest. Furthermore, a large number of worms were easily produced for the generation of transgenic C. elegans using microparticle bombardment.

Culturing Caenorhabditis elegans in Axenic Liquid Media and Creation of Transgenic Worms by Microparticle Bombardment

C. elegans is usually grown on solid agar plates or in liquid cultures seeded with E. coli. To prevent bacterial byproducts from confounding toxicological and nutritional studies, we utilized an axenic liquid medium, CeHR, to grow and synchronize a large number of worms for a range of downstream applications.

In this protocol, we present the required materials, and the procedure for making modified&#160;C. elegans&#160;Habituation and Reproduction media ...

DNA Electroporation, Isolation and Imaging of Myofibers

Mature muscle has a unique structure that is amenable to live cell imaging. Herein, we describe the experimental protocol for expressing fluorescently labeled proteins in the flexor digitorum brevis (FDB) muscle. Conditions have been optimized to provide a large number of high quality myofibers expressing the electroporated plasmid while minimizing muscle damage. The method employs fluorescent tags on various proteins. Combining this expression method with high resolution confocal microscopy permits live cell imaging, including imaging after laser-induced damage. Fluorescent dyes combined with imaging of fluorescently-tagged proteins provides information regarding the basic structure of muscle and its response to stimuli.

This protocol utilizes electroporation to introduce and express fluorescently labeled proteins in mouse muscle fibers. Following recovery after electroporation, fibers are isolated. Individual fibers are then imaged using high resolution confocal microscopy to visualize muscle structure.

Mature muscle has a unique structure that is amenable to live cell imaging. Herein, we describe the experimental protocol for expressing fluorescently ...

Avian Semen Collection by Cloacal Massage and Isolation of DNA from Sperm

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