This work was supported by the NIDDK KO1 DK075386 grant and the American Cancer Society RSG-09-075-01-MBC to Jun Sun.

This protocol includes three portions: bacterial culture, mouse gavage, and Salmonella detection.
1. Salmonella growth condition.
<ol>
	<li>Prepare the Salmonella Luria-Bertani broth (LB) plate, incubate at 37&deg; C overnight.</li>
	<li>Pick a clone from the LB plate and put into 7 ml LB in a 12 ml tube, and shake at 37&deg;C for about 5 hours.</li>
	<li>Inoculate 50 ml LB with 0.05 ml of a stationary phase culture and incubate at 37&deg;C without shaking for about 18 hours.</li>
	<li>Spin overnight bacterial culture at room temperature with 6000 rpm for 10 minutes, suspend the bacteria in HBSS using ratio 100:3 (LB: HBSS). For example: Every 50 ml LB culture will be suspended in 1.5 ml HBSS.</li>
	<li>For the animal gavage, further dilute the bacterial culture at 1:10 ratio. For example: Every 1.5 ml LB culture will be suspended in 15 ml HBSS.</li>
</ol>
2. Salmonella-infection model*.
<ol>
	<li>Prepare the streptomycin solution. Each mouse will be given 7.5 mg of streptomycin in 100 &mu;l HBSS. For example, prepare total 90 mg of streptomycin in 1.2 ml HBSS for 10 mice. Always have some extra volume when preparing the streptomycin solution.</li>
	<li>Withdraw water and food 4 hours before oral gavage treatment.</li>
	<li>Gavage mice with streptomycin with 7.5 mg of streptomycin (100 &mu;l of HBSS for control mice). Grab the skin over the mouse shoulder firmly with the thumb and middle finger, stretch the head and neck with the index finger to make the esophagus straight. Direct the ball-tip of the feeding needle along the roof of the mouth and toward the right side of the back of the pharynx, then gently pass down into the esophagus and inject the 100 &mu;l solution. No resistance should be felt.</li>
	<li>At 20 hours after streptomycin treatment, withdrawn water and food again before the mice are infected with bacteria.</li>
	<li>Gavage each mouse with 100 &#956;l suspension in HBSS or treated with sterile HBSS (control) by oral gavage. The gavage procedure is the same as 2.3) gavage mice with streptomycin.</li>
</ol>
*Animal experiments were performed by using specific-pathogen-free female C57BL/6 mice (Taconic, Hudson, NY) that were 6-7 weeks old as previously described1. The protocol was approved by the University of Rochester University Committee on Animal Resources (UCAR).
3.	Detection of Salmonella in intestine.
<ol>
	<li>Collect mouse fecal (about 100 mg).</li>
	<li>Transfer fecal sample to a 1.5 micro centrifuge tube with 1ml PBS and vortex vigorously.</li>
	<li>Centrifuge for 10 min at 800 rpm. Transfer the supernatant into a clean microfuge tube.</li>
	<li>Centrifugation at 6000 rpm for 5min. Supernatant is discarded and 200 &mu;L PBS is added to the pellets and vortexed.</li>
	<li>Streak the 200 &mu;l PBS with a disposable cell spreader on a BBL CHROMagar plate to detect Salmonella. Salmonella species appear mauve (rose to purple, see Fig.1). If 200 &mu;l yields too many colonies on the plate, use 100 &mu;l or 50 &mu;l for the streak.</li>
</ol>
4. Representative Results.
When the protocol is done correctly, Salmonella typhimurium colonization can be detected in the mouse intestine over 6 months. Salmonella could be detected by fecal culture over 6 months (Fig.1). As a typical out come of this model, body weigh loss and death occur within 4 weeks post infection. Dependent on the Salmonella strains used for infection, some mice may no survive over 6 months.
<img src="/files/ftp_upload/1947/1947fig1.jpg" alt="Figure 1" /> Figure 1. Intestinal Salmonella in the Salmonella species appear mauve (rose to purple) in color, due to metabolic differences in the presence of selected chromogens. Other bacteria are either inhibited or produce blue-green or colorless colonies.
<img src="/files/ftp_upload/1947/1947fig2.jpg" alt="Figure 2" /> Figure 2. Survival proportions of mice infected with Salmonella mutant strain PhoPc, PhoPc AvrA-, and PhoPc AvrA-/AvrA+, PhoPc AvrA for 4 weeks (28 days).
Table 1. Body weight of mice infected with Salmonella for 4 weeks.
<table border="1">
	<tbody>
		<tr>
			<td>&nbsp;</td>
			<td>0</td>
			<td>1 week</td>
			<td>2 weeks</td>
			<td>3 weeks</td>
			<td>4 week</td>
		</tr>
		<tr>
			<td>control</td>
			<td>16.78 &plusmn; 1.05</td>
			<td>16.91 &plusmn; 1.28</td>
			<td>18.26 &plusmn; 1.23</td>
			<td>19.31 &plusmn; 1.26</td>
			<td>20.26 &plusmn; 1.15</td>
		</tr>
		<tr>
			<td>PhoPc</td>
			<td>16.89 &plusmn; 1.03</td>
			<td>17.14 &plusmn; 1.19</td>
			<td>17.43 &plusmn; 1.63*</td>
			<td>18.68 &plusmn; 1.78</td>
			<td>20.05 &plusmn; 1.11</td>
		</tr>
		<tr>
			<td>PhoPcAvrA-</td>
			<td>16.91 &plusmn; 1.12</td>
			<td>16.96 &plusmn; 1.39</td>
			<td>17.06 &plusmn; 2.14**</td>
			<td>18.71 &plusmn; 2.18</td>
			<td>20.15 &plusmn; 1.56</td>
		</tr>
		<tr>
			<td>PhoPc AvrA-/AvrA+</td>
			<td>16.94 &plusmn; 0.96</td>
			<td>17.17 &plusmn; 1.02</td>
			<td>17.63 &plusmn; 1.42*</td>
			<td>18.44 &plusmn; 2.03</td>
			<td>20.09 &plusmn; 1.17</td>
		</tr>
	</tbody>
</table>
*compared to control group p&lt;0.05 
** compared to control group p&lt;0.01
Table 2. Salmonella strains used in this study.
<table border="1">
	<tbody>
		<tr>
			<td>Name</td>
			<td>Description</td>
			<td>Reference or source</td>
		</tr>
		<tr>
			<td>Salmonella 14028s</td>
			<td>Wild-type S. typhimurium</td>
			<td>ATCC</td>
		</tr>
		<tr>
			<td>PhoPc</td>
			<td>Non-pathogenic complex regulator mutant</td>
			<td>Miller et al., 1990</td>
		</tr>
		<tr>
			<td>PhoPc AvrA-</td>
			<td>AvrA- mutation</td>
			<td>Collier-Hyams et al., 2002</td>
		</tr>
		<tr>
			<td>PhoPcAvrA-/AvrA+</td>
			<td>PhoPcAvrA- with complemented plasmid encoding AvrA</td>
			<td>Collier-Hyams et al., 2002</td>
		</tr>
	</tbody>
</table>

<ol>
	<li>Duan, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=beta-Catenin+activity+negatively+regulates+bacteria-induced+inflammation.">beta-Catenin activity negatively regulates bacteria-induced inflammation.</a> Lab Invest. 87 (6), 613-624 (2007).</li><li>Barthel, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pretreatment+of+mice+with+streptomycin+provides+a+Salmonella+enterica+serovar+Typhimurium+colitis+model+that+allows+analysis+of+both+pathogen+and+host.">Pretreatment of mice with streptomycin provides a Salmonella enterica serovar Typhimurium colitis model that allows analysis of both pathogen and host.</a> Infection and immunity. 71 (5), 2839-2858 (2003).</li><li>Miller, S. I., Mekalanos, J. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Constitutive+expression+of+the+phoP+regulon+attenuates+Salmonella+virulence+and+survival+within+macrophages.">Constitutive expression of the phoP regulon attenuates Salmonella virulence and survival within macrophages.</a> Journal of bacteriology. 172 (5), 2485-2490 (1990).</li><li>Valdez, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nramp1+expression+by+dendritic+cells+modulates+inflammatory+responses+during+Salmonella+Typhimurium+infection.">Nramp1 expression by dendritic cells modulates inflammatory responses during Salmonella Typhimurium infection.</a> Cell Microbiol. 10 (8), 1646-1661 (2008).</li><li>Woo, H., Okamoto, S., Guiney, D., Gunn, J. S., Fierer, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+model+of+Salmonella+colitis+with+features+of+diarrhea+in+SLC11A1+wild-type+mice.">A model of Salmonella colitis with features of diarrhea in SLC11A1 wild-type mice.</a> PLoS ONE. 3 (2), e1603-e1603 (2008).</li><li>Dangl, J. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Molecular+call-and-response:+how+Salmonella+learns+the+gospel+from+its+host.">Molecular call-and-response: how Salmonella learns the gospel from its host.</a> Trends Microbiol. 11 (6), 245-246 (2003).</li><li>Zaharik, M. L., Vallance, B. A., Puente, J. L., Gros, P., Finlay, B. 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L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Humane+endpoints+for+infectious+disease+animal+models.">Humane endpoints for infectious disease animal models.</a> ILAR J. 41 (2), 99-104 (2000).</li><li>Ye, Z., Petrof, E. O., Boone, D., Claud, E. C., Sun, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Salmonella+effector+AvrA+regulation+of+colonic+epithelial+cell+inflammation+by+deubiquitination.">Salmonella effector AvrA regulation of colonic epithelial cell inflammation by deubiquitination.</a> Am J Pathol. 171 (3), 882-892 (2007).</li><li>Grassl, G. A., Valdez, Y., Bergstrom, K. S., Vallance, B. A., Finlay, B. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chronic+enteric+salmonella+infection+in+mice+leads+to+severe+and+persiste+nt+intestinal+fibrosis.">Chronic enteric salmonella infection in mice leads to severe and persiste nt intestinal fibrosis.</a> Gastroenterology. 134 (3), 768-780 (2008).</li><li>Sukupolvi, S., Edelstein, A., Rhen, M., Normark, S. J., Pfeifer, J. 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No conflicts of interest declared.

To use this system, it is necessary for the researcher to learn how to gavage the animals. We detail a methodology for prepare bacterial culture and gavage the mice. We also show how to monitor the Salmonella persistence in the gastrointestinal (GI) tract. The critical steps in this protocol including: <ol> <li>Streptomycin-pretreatment: Streptomycin-pretreatment could get rid of some commensal gut flora and make the mice susceptible to the Salmonella infection2.</li> <li>Salmonell...

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		<div>
		<table border="1">
		<thead>
		<tr>
		<th>Material Name</th>
		<th>Type</th>
		<th>Company</th>
		<th>Catalogue Number</th>
		<th>Comment</th>
		</tr>
		</thead>
		<tbody>
		
<tr>
<td>HBSS</td>
<td>&nbsp;</td>
<td>Sigma</td>
<td>ABCD1234</td>
<td>&nbsp;</td>
<tr>
<td>Luria-Bertani broth</td>
<td>&nbsp;</td>
<td>BD</td>
<td>244610</td>
<td>&nbsp;</td>
<tr>
<td>Feeding needle</td>
<td>&nbsp;</td>
<td>Popper &amp; Sons, Inc</td>
<td>7920</td>
<td>&nbsp;</td>
<tr>
<td>Streptomycin </td>
<td>&nbsp;</td>
<td>MP biomedicals, LLC</td>
<td>100556</td>
<td>&nbsp;</td>
<tr>
<td>BBL CHROMagar Salmonella</td>
<td>&nbsp;</td>
<td>BD</td>
<td>214983</td>
<td>&nbsp;</td>
<tr>
<td>Disposable cell spreaders</td>
<td>&nbsp;</td>
<td>Biologix research company</td>
<td>65-1010</td>
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chronic salmonella infected mouse model

The bacterial infected mouse model is a powerful model system for studying areas such as infection, inflammation, immunology, signal transduction, and tumorigenesis. Many researchers have taken advantage of the colitis induced by Salmonella typhimurium for the studies on the early phase of inflammation and infection. However, only few reports are on the chronic infection in vivo. Mice with Salmonella persistent existence in the gastrointestinal tract allow us to explore the long-term host-bacterial interaction, signal transduction, and tumorigenesis. We have established a chronic bacterial infected mouse model with Salmonella typhimurium colonization in the mouse intestine over 6 months. To use this system, it is necessary for the researcher to learn how to prepare the bacterial culture and gavage the animals. We detail a methodology for prepare bacterial culture and gavage mice. We also show how to detect the Salmonella persistence in the gastrointestinal tract. Overall, this protocol will aid researchers using the bacterial infected mouse model to address fundamentally important biological and microbiological questions.

Watch this Scientific Journal Video about Chronic Salmonella Infected Mouse Model at JoVE.com

Chronic Salmonella Infected Mouse Model

Establish a chronic bacterial infected mouse model with persistent Salmonella typhimurium colonization in intestine for 27 weeks.

Chronic Salmonella Infected Mouse Model

The bacterial infected mouse model is a powerful model system for studying areas such as infection, inflammation, immunology, signal transduction, and ...

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17.2K Views.  University of Rochester. Создание хронического бактериального инфицированных мышах со стойкими Сальмонеллы Typhimurium колонизации в кишечнике в течение 27 недель.

Video: Chronic Salmonella Infected Mouse Model

Orthotopic Mouse Model of Colorectal Cancer

The traditional subcutaneous tumor model is less than ideal for studying colorectal cancer. Orthotopic mouse models of colorectal cancer, which feature cancer cells growing in their natural location, replicate human disease with high fidelity. Two techniques can be used to establish this model. Both techniques are similar and require mouse anesthesia and laparotomy for exposure of the cecum. One technique involves injection of a colorectal cancer cell suspension into the cecal wall. Cancer cells are first grown in culture, harvested when subconfluent and prepared as a single cell suspension. A small volume of cells is injected slowly to avoid leakage. The other technique involves transplantation of a piece of subcutaneous tumor onto the cecum. A mouse with a previously established subcutaneous colorectal tumor is euthanized and the tumor is removed using sterile technique. The tumor piece is divided into small pieces for transplantation to another mouse. Prior to transplantation, the cecal wall is lightly damaged to facilitate tumor cell infiltration. The time to developing primary tumors and liver metastases will vary depending on the technique, cell line, and mouse species used. This orthotopic mouse model is useful for studying the natural progression of colorectal cancer and testing new therapeutic agents against colorectal cancer.

Two techniques can be used to establish this model: injection of a cancer cell suspension into the cecal wall or transplantation of a piece of subcutaneous tumor onto the cecum. This model is useful for studying the natural progression of colorectal cancer and testing new therapeutic agents against colorectal cancer.

The traditional subcutaneous tumor model is less than ideal for studying colorectal cancer. Orthotopic mouse models of colorectal cancer, which feature ...

Laser-Induced Chronic Ocular Hypertension Model on SD Rats

Glaucoma is one of the major causes of blindness in the world. Elevated intraocular pressure is a major risk factor. Laser photocoagulation induced ocular hypertension is one of the well established animal models. This video demonstrates how to induce ocular hypertension by Argon laser photocoagulation in rat.

Glaucoma is one of the major causes of blindness in the world. Elevated intraocular pressure is a major risk factor. Laser photocoagulation induced ocular hypertension is one of the well established animal models. This video demonstrates how to induce ocular hypertension by Argon laser photocoagulation in rat.

Glaucoma is one of the major causes of blindness in the world. Elevated intraocular pressure is a major risk factor. Laser photocoagulation induced ocular ...

Immunohistochemistry on Paraffin Sections of Mouse Epidermis Using Fluorescent Antibodies

In the epidermis, immunohistochemistry is an efficient means of localizing specific proteins to their relative expression compartment; namely the basal, suprabasal, and stratum corneum layers. The precise localization within the epidermis of a particular protein lends clues toward its functional role within the epidermis. In this chapter, we describe a reliable method for immunolocalization within the epidermis modified for both frozen and paraffin sections that we use very routinely in our laboratory. Paraffin sections generally provide much better morphology, hence, superior results and photographs; however, not all antibodies will work with the harsh fixation and treatment involved in their processing. Therefore, the protocol for frozen sectioning is also included. Within paraffin sectioning, two fixation protocols are described (Bouin's and paraformaldehyde); the choice of fixative will be directly related to the antibody specifications and may require another fixing method.

We describe a reliable method for immunolocalization within the epidermis modified for both frozen and paraffin sections that we use very routinely in our laboratory.

In the epidermis, immunohistochemistry is an efficient means of localizing specific proteins to their relative expression compartment; namely the basal, ...

In vivo Imaging and Therapeutic Treatments in an Orthotopic Mouse Model of Ovarian Cancer

Human cancer and response to therapy is better represented in orthotopic animal models. This paper describes the development of an orthotopic mouse model of ovarian cancer, treatment of cancer via oral delivery of drugs, and monitoring of tumor cell behavior in response to drug treatment in real time using in vivo imaging system. In this orthotopic model, ovarian tumor cells expressing luciferase are applied topically by injecting them directly into the mouse bursa where each ovary is enclosed. Upon injection of D-luciferin, a substrate of firefly luciferase, luciferase-expressing cells generate bioluminescence signals. This signal is detected by the in vivo imaging system and allows for a non-invasive means of monitoring tumor growth, distribution, and regression in individual animals. Drug administration via oral gavage allows for a maximum dosing volume of 10 mL/kg body weight to be delivered directly to the stomach and closely resembles delivery of drugs in clinical treatments. Therefore, techniques described here, development of an orthotopic mouse model of ovarian cancer, oral delivery of drugs, and in vivo imaging, are useful for better understanding of human ovarian cancer and treatment and will improve targeting this disease.

In vivo Imaging and Therapeutic Treatments in an Orthotopic Mouse Model of Ovarian Cancer

Orthotopic animal models of ovarian cancer replicate better human disease and therefore enhance our understanding of cancer progression and tumor response to therapy. A mouse model receives an intrabursal injection of luciferase-expressing ovarian tumor cells. Treatment is administered via oral gavage. Tumor growth is monitored by in vivo imaging system.

Human cancer and response to therapy is better represented in orthotopic animal models.  This paper describes the development of an orthotopic mouse model ...

Generation of Mice Derived from Induced Pluripotent Stem Cells

The production of induced pluripotent stem cells (iPSCs) from somatic cells provides a means to create valuable tools for basic research and may also produce a source of patient-matched cells for regenerative therapies. iPSCs may be generated using multiple protocols and derived from multiple cell sources. Once generated, iPSCs are tested using a variety of assays including immunostaining for pluripotency markers, generation of three germ layers in embryoid bodies and teratomas, comparisons of gene expression with embryonic stem cells (ESCs) and production of chimeric mice with or without germline contribution2. Importantly, iPSC lines that pass these tests still vary in their capacity to produce different differentiated cell types2. This has made it difficult to establish which iPSC derivation protocols, donor cell sources or selection methods are most useful for different applications.
The most stringent test of whether a stem cell line has sufficient developmental potential to generate all tissues required for survival of an organism (termed full pluripotency) is tetraploid embryo complementation (TEC)3-5. Technically, TEC involves electrofusion of two-cell embryos to generate tetraploid (4n) one-cell embryos that can be cultured in vitro to the blastocyst stage6. Diploid (2n) pluripotent stem cells (e.g. ESCs or iPSCs) are then injected into the blastocoel cavity of the tetraploid blastocyst and transferred to a recipient female for gestation (see Figure 1). The tetraploid component of the complemented embryo contributes almost exclusively to the extraembryonic tissues (placenta, yolk sac), whereas the diploid cells constitute the embryo proper, resulting in a fetus derived entirely from the injected stem cell line.
Recently, we reported the derivation of iPSC lines that reproducibly generate adult mice via TEC1. These iPSC lines give rise to viable pups with efficiencies of 5-13%, which is comparable to ESCs3,4,7 and higher than that reported for most other iPSC lines8-12. These reports show that direct reprogramming can produce fully pluripotent iPSCs that match ESCs in their developmental potential and efficiency of generating pups in TEC tests. At present, it is not clear what distinguishes between fully pluripotent iPSCs and less potent lines13-15. Nor is it clear which reprogramming methods will produce these lines with the highest efficiency. Here we describe one method that produces fully pluripotent iPSCs and "all- iPSC" mice, which may be helpful for investigators wishing to compare the pluripotency of iPSC lines or establish the equivalence of different reprogramming methods.

Generating induced pluripotent stem cell (iPSC) lines produces lines of differing developmental potential even when they pass standard tests for pluripotency. Here we describe a protocol to produce mice derived entirely from iPSCs, which defines the iPSC lines as possessing full pluripotency1.

The production of induced pluripotent stem cells (iPSCs) from somatic cells provides a means to create valuable tools for basic research and may also ...

The Murine Choline-Deficient, Ethionine-Supplemented (CDE) Diet Model of Chronic Liver Injury

Chronic liver diseases, such as viral hepatitis, alcoholic liver disease, or non-alcoholic fatty liver disease, are characterized by continual inflammation, progressive destruction and regeneration of the hepatic parenchyma, liver progenitor cell proliferation, and fibrosis. The end-stage of every chronic liver disease is cirrhosis, a major risk factor for the development of hepatocellular carcinoma. To study processes regulating disease initiation, establishment, and progression, several animal models are used in laboratories. Here we describe a six-week time course of the choline-deficient and ethionine-supplemented (CDE) mouse model, which involves feeding six-week old male C57BL/6J mice with choline-deficient chow and 0.15% DL-ethionine-supplemented drinking water. Monitoring of animal health and a typical body weight loss curve are explained. The protocol demonstrates the gross examination of a CDE-treated liver and blood collection by cardiac puncture for subsequent serum analyses. Next, the liver perfusion technique and collection of different hepatic lobes for standard evaluations are shown, including liver histology assessments by hematoxylin and eosin or Sirius Red stainings, immunofluorescent detection of hepatic cell populations as well as transcriptome profiling of the liver microenvironment. This mouse model is suitable for studying inflammatory, fibrogenic, and liver progenitor cell dynamics induced through chronic liver disease and can be used to test potential therapeutic agents that may modulate these processes.

The Murine Choline-Deficient, Ethionine-Supplemented CDE Diet Model of Chronic Liver Injury

Here we describe a common method to induce chronic liver injury in mice by feeding of a choline-deficient and ethionine-supplemented (CDE) diet. We demonstrate health monitoring, liver perfusion, isolation, and preservation. A time course of six weeks can inform about liver injury, pathohistology, fibrosis, inflammatory, and liver progenitor cell responses.

Chronic liver diseases, such as viral hepatitis, alcoholic liver disease, or non-alcoholic fatty liver disease, are characterized by continual ...

Trans-inner Cell Mass Injection of Embryonic Stem Cells Leads to Higher Chimerism Rates

In an effort to increase efficiency in the creation of genetically modified mice via ES Cell methodologies, we present an adaptation to the current blastocyst injection protocol. Here we report that a simple rotation of the embryo, and injection through Trans-Inner cell mass (TICM) increased the percentage of chimeric mice from 31% to 50%, with no additional equipment or further specialized training. 26 different inbred clones, and 35 total clones were injected over a period of 9 months. There was no significant difference in either pregnancy rate or recovery rate of embryos between traditional injection techniques and TICM. Therefore, without any major alteration in the injection process and a simple positioning of the blastocyst and injecting through the ICM, releasing the ES cells into the blastocoel cavity can potentially improve the quantity of chimeric production and subsequent germline transmission.

Here we present a protocol to increase chimera production without the use of new equipment. A simple orientation change of the embryo for injection can increase the number of embryos produced, and potentially reduce the timeline to germline transmission.

In an effort to increase efficiency in the creation of genetically modified mice via ES Cell methodologies, we present an adaptation to the current ...

A Mouse Model of Intestinal Partial Obstruction

Intestinal obstructions, that impede or block peristaltic movement, can be caused by abdominal adhesions and most gastrointestinal (GI) diseases including tumorous growths. However, the cellular remodeling mechanisms involved in, and caused by, intestinal obstructions are poorly understood. Several animal models of intestinal obstructions have been developed, but the mouse model is the most cost/time effective. The mouse model uses the surgical implantation of an intestinal partial obstruction (PO) that has a high mortality rate if it is not performed correctly. In addition, mice receiving PO surgery fail to develop hypertrophy if an appropriate blockade is not used or not properly placed. Here, we describe a detailed protocol for PO surgery which produces reliable and reproducible intestinal obstructions with a very low mortality rate. This protocol utilizes a surgically placed silicone ring that surrounds the ileum which partially blocks digestive movement in the small intestine. The partial blockage makes the intestine become dilated due to the halt of digestive movement. The dilation of the intestine induces smooth muscle hypertrophy on the oral side of the ring that progressively develops over 2 weeks until it causes death. The surgical PO mouse model offers an in vivo model of hypertrophic intestinal tissue useful for studying pathological changes of intestinal cells including smooth muscle cells (SMC), interstitial cells of Cajal (ICC), PDGFR&#945;+, and neuronal cells during the development of intestinal obstruction.

Intestinal obstructions are a partial or complete blockage of the intestine that can cause severe abdominal pain, nausea, vomiting, and preventing the passage of stool. This procedure for creating intestinal partial obsructions in mice is reliable in studying the mechanisms underlying pathological cell growth and death in the intestine.

Intestinal obstructions, that impede or block peristaltic movement, can be caused by abdominal adhesions and most gastrointestinal (GI) diseases including ...

Quasi-metagenomic Analysis of Salmonella from Food and Environmental Samples

Quasi-metagenomics sequencing refers to the sequencing-based analysis of modified microbiomes of food and environmental samples. In this protocol, microbiome modification is designed to concentrate genomic DNA of a target foodborne pathogen contaminant to facilitate the detection and subtyping of the pathogen in a single workflow. Here, we explain and demonstrate the sample preparation steps for the quasi-metagenomics analysis of Salmonella enterica from representative food and environmental samples including alfalfa sprouts, ground black pepper, ground beef, chicken breast and environmental swabs. Samples are first subjected to the culture enrichment of Salmonella for a shortened and adjustable duration (4&#8211;24 h). Salmonella cells are then selectively captured from the enrichment culture by immunomagnetic separation (IMS). Finally, multiple displacement amplification (MDA) is performed to amplify DNA from IMS-captured cells. The DNA output of this protocol can be sequenced by high throughput sequencing platforms. An optional quantitative PCR analysis can be performed to replace sequencing for Salmonella detection or assess the concentration of Salmonella DNA before sequencing.

Quasi-metagenomic Analysis of Salmonella from Food and Environmental Samples

Here, we present a protocol to prepare DNA samples from food and environmental microbiomes for concerted detection and subtyping of Salmonella through quasimetagenomic sequencing. The combined use of culture enrichment, immunomagnetic separation (IMS), and multiple displacement amplification (MDA) allows effective concentration of Salmonella genomic DNA from food and environmental samples.&#160;

Quasi-metagenomics sequencing refers to the sequencing-based analysis of modified microbiomes of food and environmental samples. In this protocol, ...

Mass Spectrometry Analysis to Identify Ubiquitylation of EYFP-tagged CENP-A (EYFP-CENP-A)

Studying the structure and the dynamics of kinetochores and centromeres is important in understanding chromosomal instability (CIN) and cancer progression. How the chromosomal location and function of a centromere (i.e., centromere identity) are determined and participate in accurate chromosome segregation is a fundamental question. CENP-A is proposed to be the non-DNA indicator (epigenetic mark) of centromere identity, and CENP-A ubiquitylation is required for CENP-A deposition at the centromere, inherited through dimerization between cell division, and indispensable to cell viability.
Here we describe mass spectrometry analysis to identify ubiquitylation of EYFP-CENP-A K124R mutant suggesting that ubiquitylation at a different lysine is induced because of the EYFP tagging in the CENP-A K124R mutant protein. Lysine 306 (K306) ubiquitylation in EYFP-CENP-A K124R was successfully identified, which corresponds to lysine 56 (K56) in CENP-A through mass spectrometry analysis. A caveat is discussed in the use of GFP/EYFP or the tagging of high molecular weight protein as a tool to analyze the function of a protein. Current technical limit is also discussed for the detection of ubiquitylated bands, identification of site-specific ubiquitylation(s), and visualization of ubiquitylation in living cells or a specific single cell during the whole cell cycle.
The method of mass spectrometry analysis presented here can be applied to human CENP-A protein with different tags and other centromere-kinetochore proteins. These combinatory methods consisting of several assays/analyses could be recommended for researchers who are interested in identifying functional roles of ubiquitylation.

Mass Spectrometry Analysis to Identify Ubiquitylation of EYFP-tagged CENP-A EYFP-CENP-A

CENP-A ubiquitylation is an important requirement for CENP-A deposition at the centromere, inherited through dimerization between cell division, and indispensable to cell viability. Here we describe mass spectrometry analysis to identify ubiquitylation of EYFP-tagged CENP-A (EYFP-CENP-A) protein.