http://2010.igem.org/wiki/index.php?title=Team:Queens-Canada/digestive&feed=atom&action=historyTeam:Queens-Canada/digestive - Revision history2024-03-29T00:45:33ZRevision history for this page on the wikiMediaWiki 1.16.5http://2010.igem.org/wiki/index.php?title=Team:Queens-Canada/digestive&diff=197807&oldid=prevGlh at 21:47, 27 October 20102010-10-27T21:47:29Z<p></p>
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<tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div><html><div class="section"><h2>The Pharynx</h2></html></div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div><html><div class="section"><h2>The Pharynx</h2></html></div></td></tr>
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<tr><td class='diff-marker'>-</td><td style="background: #ffa; color:black; font-size: smaller;"><div><<del class="diffchange diffchange-inline">picture</del>></div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><<ins class="diffchange diffchange-inline">html><center><img src="http://wormatlas.org/hermaphrodite/pharynx/Images/PhaFIG2lr.jpg" style="width: 100%; max-width: 700px; box-shadow: 1px 2px 3px #808080"><br></ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins class="diffchange diffchange-inline"><a target="_new" href="http://wormatlas.org/hermaphrodite/pharynx/Images/phafig2leg.htm">From <i>WormAtlas</i></a></center></html</ins>></div></td></tr>
<tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr>
<tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>The pharynx is a complex structure that precedes the intestine. Quite unlike the human pharynx, it is a combination of pump and grinder, and it has been theorized to bear some homology to the heart of other organisms based on its selection of ion pumps, developmental independence, and the nature of its innervation.</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>The pharynx is a complex structure that precedes the intestine. Quite unlike the human pharynx, it is a combination of pump and grinder, and it has been theorized to bear some homology to the heart of other organisms based on its selection of ion pumps, developmental independence, and the nature of its innervation.</div></td></tr>
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<tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div><html><div class="section"><h2>The Intestine</h2></html></div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div><html><div class="section"><h2>The Intestine</h2></html></div></td></tr>
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<tr><td class='diff-marker'>-</td><td style="background: #ffa; color:black; font-size: smaller;"><div><<del class="diffchange diffchange-inline">picture</del>></div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><<ins class="diffchange diffchange-inline">html><center><img src="http://wormatlas.org/hermaphrodite/intestine/Images/IntFIG1lr.jpg" style="width: 100%; max-width: 800px; box-shadow: 1px 2px 3px #808080"><br></ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins class="diffchange diffchange-inline"><a target="_new" href="http://wormatlas.org/hermaphrodite/intestine/Images/intfig1leg.htm">From <i>WormAtlas</i></a></center></html</ins>></div></td></tr>
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<tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>The intestine is a long tube that spans most of the creature’s body. It is comprised of twenty cells which form rings down the length of the worm’s interior. With the exception of the grinding activity provided by the pharynx, and defecation provided by the anus, the intestine of ''C. elegans'' performs most of the digestive functions of higher organisms, including chemical breakdown of food, absorption of nutrient molecules, and synthesis and storage of fats. For a long time, the worm’s digestive system was very poorly understood, but this is steadily being corrected in combination with knowledge of the digestive systems of other nematodes.</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>The intestine is a long tube that spans most of the creature’s body. It is comprised of twenty cells which form rings down the length of the worm’s interior. With the exception of the grinding activity provided by the pharynx, and defecation provided by the anus, the intestine of ''C. elegans'' performs most of the digestive functions of higher organisms, including chemical breakdown of food, absorption of nutrient molecules, and synthesis and storage of fats. For a long time, the worm’s digestive system was very poorly understood, but this is steadily being corrected in combination with knowledge of the digestive systems of other nematodes.</div></td></tr>
</table>Glhhttp://2010.igem.org/wiki/index.php?title=Team:Queens-Canada/digestive&diff=136578&oldid=prevGlh at 19:32, 24 October 20102010-10-24T19:32:53Z<p></p>
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<tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>Although nematodes in general typically grind up bacteria before they reach the intestine, there are some cases in which bacteria circumvent the normal pharynx function and successfully colonize the intestinal surface, with typically detrimental effects to the host worm. Several species are known to attack ''C. elegans'' in this way, and worms particularly vulnerable to intestinal colonization due to mutations are said to be of the ''BUS'' phenotype; a family of genes has been named ''bus'', appropriately. However, there are other nematode species where colonization isn’t doom for the worm: ''Steinernema carpocapsae'', a parasitic nematode that parasitizes wasp larvae, [http://www.ncbi.nlm.nih.gov/pubmed/17618298 forms an effective symbiosis with the bacterial species ''Xenorhabdus nematophila''], which is necessary for killing the insects and assisting the worm’s mode of reproduction.</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>Although nematodes in general typically grind up bacteria before they reach the intestine, there are some cases in which bacteria circumvent the normal pharynx function and successfully colonize the intestinal surface, with typically detrimental effects to the host worm. Several species are known to attack ''C. elegans'' in this way, and worms particularly vulnerable to intestinal colonization due to mutations are said to be of the ''BUS'' phenotype; a family of genes has been named ''bus'', appropriately. However, there are other nematode species where colonization isn’t doom for the worm: ''Steinernema carpocapsae'', a parasitic nematode that parasitizes wasp larvae, [http://www.ncbi.nlm.nih.gov/pubmed/17618298 forms an effective symbiosis with the bacterial species ''Xenorhabdus nematophila''], which is necessary for killing the insects and assisting the worm’s mode of reproduction.</div></td></tr>
<tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr>
<tr><td class='diff-marker'>-</td><td style="background: #ffa; color:black; font-size: smaller;"><div>No immediate barrier is apparent to the thought of transferring the genes that make this colonization possible into ''C. elegans'' and ''E. coli'', although this is obviously a great deal of work, and the tendency to retain bacteria as engendered in ''bus'' mutants can most likely reproduce the effect at a sufficient rate and worm longevity for most projects. Like the exosymbiosis suggested in [[Team:Queens-Canada/<del class="diffchange diffchange-inline">exterior</del>|the cuticle article]], this system of enterosymbiosis presents a great opportunity for inter-kingdom cooperation and backward compatibility with the fundamental ''E. coli'' chassis.<html></div></html></div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div>No immediate barrier is apparent to the thought of transferring the genes that make this colonization possible into ''C. elegans'' and ''E. coli'', although this is obviously a great deal of work, and the tendency to retain bacteria as engendered in ''bus'' mutants can most likely reproduce the effect at a sufficient rate and worm longevity for most projects. Like the exosymbiosis suggested in [[Team:Queens-Canada/<ins class="diffchange diffchange-inline">skin</ins>|the cuticle article]], this system of enterosymbiosis presents a great opportunity for inter-kingdom cooperation and backward compatibility with the fundamental ''E. coli'' chassis.<html></div></html></div></td></tr>
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<tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>'''[[Team:Queens-Canada/nervous|Continue to the Nervous System]]'''</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>'''[[Team:Queens-Canada/nervous|Continue to the Nervous System]]'''</div></td></tr>
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<tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>{{:Team:Queens-Canada/foot}}</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>{{:Team:Queens-Canada/foot}}</div></td></tr>
</table>Glhhttp://2010.igem.org/wiki/index.php?title=Team:Queens-Canada/digestive&diff=136575&oldid=prevGlh at 19:32, 24 October 20102010-10-24T19:32:25Z<p></p>
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<tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>Several of the cells in the worm’s intestine have two nuclei after the L1 stage of larval development. The purpose and value of this is not known, and preventing it by knocking out the gene ''lin-14'' does not seem to affect the worm adversely. This property may be potentially exploitable as a means to insert a foreign molecule into the nucleus before telophase begins after this superfluous division. The intestine is something of a hot spot for peculiar nucleic acid activity—[[Team:Queens-Canada/rnai|dsRNA]] is normally taken up in the intestine, through the SID-2 channel lining the lumen, and then propagates throughout the worm (except neurons) via SID-1.</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>Several of the cells in the worm’s intestine have two nuclei after the L1 stage of larval development. The purpose and value of this is not known, and preventing it by knocking out the gene ''lin-14'' does not seem to affect the worm adversely. This property may be potentially exploitable as a means to insert a foreign molecule into the nucleus before telophase begins after this superfluous division. The intestine is something of a hot spot for peculiar nucleic acid activity—[[Team:Queens-Canada/rnai|dsRNA]] is normally taken up in the intestine, through the SID-2 channel lining the lumen, and then propagates throughout the worm (except neurons) via SID-1.</div></td></tr>
<tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr>
<tr><td class='diff-marker'>-</td><td style="background: #ffa; color:black; font-size: smaller;"><div>Although nematodes in general typically grind up bacteria before they reach the intestine, there are some cases in which bacteria circumvent the normal pharynx function and successfully colonize the intestinal surface, with typically detrimental effects to the host worm. Several species are known to attack ''C. elegans'' in this way, and worms particularly vulnerable to intestinal colonization due to mutations are said to be of the BUS phenotype; a family of genes has been named bus, appropriately. However, there are other nematode species where colonization isn’t doom for the worm: ''Steinernema carpocapsae'', a parasitic nematode that parasitizes wasp larvae, [http://www.ncbi.nlm.nih.gov/pubmed/17618298 forms an effective symbiosis with the bacterial species ''Xenorhabdus nematophila''], which is necessary for killing the insects and assisting the worm’s mode of reproduction.</div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div>Although nematodes in general typically grind up bacteria before they reach the intestine, there are some cases in which bacteria circumvent the normal pharynx function and successfully colonize the intestinal surface, with typically detrimental effects to the host worm. Several species are known to attack ''C. elegans'' in this way, and worms particularly vulnerable to intestinal colonization due to mutations are said to be of the <ins class="diffchange diffchange-inline">''</ins>BUS<ins class="diffchange diffchange-inline">'' </ins>phenotype; a family of genes has been named <ins class="diffchange diffchange-inline">''</ins>bus<ins class="diffchange diffchange-inline">''</ins>, appropriately. However, there are other nematode species where colonization isn’t doom for the worm: ''Steinernema carpocapsae'', a parasitic nematode that parasitizes wasp larvae, [http://www.ncbi.nlm.nih.gov/pubmed/17618298 forms an effective symbiosis with the bacterial species ''Xenorhabdus nematophila''], which is necessary for killing the insects and assisting the worm’s mode of reproduction.</div></td></tr>
<tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr>
<tr><td class='diff-marker'>-</td><td style="background: #ffa; color:black; font-size: smaller;"><div>No immediate barrier is apparent to the thought of transferring the genes that make this colonization possible into ''C. elegans'' and ''E. coli'', although this is obviously a great deal of work, and bus mutants can most likely reproduce the effect <del class="diffchange diffchange-inline">to great success </del>at a sufficient rate for most projects. Like the exosymbiosis suggested in [[Team:Queens-Canada/exterior|the cuticle article]], this system of enterosymbiosis presents a great opportunity for inter-kingdom cooperation and backward compatibility with the fundamental ''E. coli'' chassis.<html></div></html></div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div>No immediate barrier is apparent to the thought of transferring the genes that make this colonization possible into ''C. elegans'' and ''E. coli'', although this is obviously a great deal of work, and <ins class="diffchange diffchange-inline">the tendency to retain bacteria as engendered in ''</ins>bus<ins class="diffchange diffchange-inline">'' </ins>mutants can most likely reproduce the effect at a sufficient rate <ins class="diffchange diffchange-inline">and worm longevity </ins>for most projects. Like the exosymbiosis suggested in [[Team:Queens-Canada/exterior|the cuticle article]], this system of enterosymbiosis presents a great opportunity for inter-kingdom cooperation and backward compatibility with the fundamental ''E. coli'' chassis.<html></div></html></div></td></tr>
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<tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>'''[[Team:Queens-Canada/nervous|Continue to the Nervous System]]'''</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>'''[[Team:Queens-Canada/nervous|Continue to the Nervous System]]'''</div></td></tr>
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<tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>{{:Team:Queens-Canada/foot}}</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>{{:Team:Queens-Canada/foot}}</div></td></tr>
</table>Glhhttp://2010.igem.org/wiki/index.php?title=Team:Queens-Canada/digestive&diff=136565&oldid=prevGlh at 19:31, 24 October 20102010-10-24T19:31:06Z<p></p>
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<tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>Although nematodes in general typically grind up bacteria before they reach the intestine, there are some cases in which bacteria circumvent the normal pharynx function and successfully colonize the intestinal surface, with typically detrimental effects to the host worm. Several species are known to attack ''C. elegans'' in this way, and worms particularly vulnerable to intestinal colonization due to mutations are said to be of the BUS phenotype; a family of genes has been named bus, appropriately. However, there are other nematode species where colonization isn’t doom for the worm: ''Steinernema carpocapsae'', a parasitic nematode that parasitizes wasp larvae, [http://www.ncbi.nlm.nih.gov/pubmed/17618298 forms an effective symbiosis with the bacterial species ''Xenorhabdus nematophila''], which is necessary for killing the insects and assisting the worm’s mode of reproduction.</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>Although nematodes in general typically grind up bacteria before they reach the intestine, there are some cases in which bacteria circumvent the normal pharynx function and successfully colonize the intestinal surface, with typically detrimental effects to the host worm. Several species are known to attack ''C. elegans'' in this way, and worms particularly vulnerable to intestinal colonization due to mutations are said to be of the BUS phenotype; a family of genes has been named bus, appropriately. However, there are other nematode species where colonization isn’t doom for the worm: ''Steinernema carpocapsae'', a parasitic nematode that parasitizes wasp larvae, [http://www.ncbi.nlm.nih.gov/pubmed/17618298 forms an effective symbiosis with the bacterial species ''Xenorhabdus nematophila''], which is necessary for killing the insects and assisting the worm’s mode of reproduction.</div></td></tr>
<tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr>
<tr><td class='diff-marker'>-</td><td style="background: #ffa; color:black; font-size: smaller;"><div>No immediate barrier is apparent to the thought of transferring the genes that make this colonization possible into ''C. elegans'' and ''E. coli'', although this is obviously a great deal of work, and bus mutants can most likely reproduce the effect to great success at a sufficient rate for most projects. Like the exosymbiosis suggested in the cuticle article <del class="diffchange diffchange-inline"><link></del>, this system of enterosymbiosis presents a great opportunity for inter-kingdom cooperation and backward compatibility with the fundamental ''E. coli'' chassis.<html></div></html></div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div>No immediate barrier is apparent to the thought of transferring the genes that make this colonization possible into ''C. elegans'' and ''E. coli'', although this is obviously a great deal of work, and bus mutants can most likely reproduce the effect to great success at a sufficient rate for most projects. Like the exosymbiosis suggested in <ins class="diffchange diffchange-inline">[[Team:Queens-Canada/exterior|</ins>the cuticle article<ins class="diffchange diffchange-inline">]]</ins>, this system of enterosymbiosis presents a great opportunity for inter-kingdom cooperation and backward compatibility with the fundamental ''E. coli'' chassis.<html></div></html></div></td></tr>
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<tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>'''[[Team:Queens-Canada/nervous|Continue to the Nervous System]]'''</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>'''[[Team:Queens-Canada/nervous|Continue to the Nervous System]]'''</div></td></tr>
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<tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>{{:Team:Queens-Canada/foot}}</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>{{:Team:Queens-Canada/foot}}</div></td></tr>
</table>Glhhttp://2010.igem.org/wiki/index.php?title=Team:Queens-Canada/digestive&diff=136547&oldid=prevGlh at 19:29, 24 October 20102010-10-24T19:29:40Z<p></p>
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<tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div><h1>The Digestive System</h1></div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div><h1>The Digestive System</h1></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;"></ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;">The ''C. elegans'' digestive system is divided into two components: the '''pharynx''', which breaks down food by grinding it up, and the '''intestine''', where food is digested, absorbed, and stored. The intestine is a major component of the worm, by mass a whole third of its somatic cells, and presents many interesting opportunities for synthetic biology through the prospects of enterosymbiosis with bacteria and the potential localization of catalytic pathways.</ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;"></ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;"><html><div class="section"><h2>The Pharynx</h2></html></ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;"></ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;"><picture></ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;"></ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;">The pharynx is a complex structure that precedes the intestine. Quite unlike the human pharynx, it is a combination of pump and grinder, and it has been theorized to bear some homology to the heart of other organisms based on its selection of ion pumps, developmental independence, and the nature of its innervation.</ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;"></ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;">The pharynx normally takes in bacteria-filled water, pushes the water back out, grinds up the bacteria, and then passes them along to the intestine. The grinder, located in the terminal bulb, is very fine, and unless disrupted by the activity of a pathogenic bacterium, cuts up the food. The pump rate is dependent on the detection of food and recent periods of starvation, but it never stops.</ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;"></ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;">One of the primary interests synthetic biology may have with the ''C. elegans'' pharynx is in circumventing its behavior sufficiently for symbiotic, beneficial colonization of the worm’s intestine by an engineered bacterial strain (enterosymbiosis). While this goal may seem remote at first inspection, consider that [http://www.wormbook.org/chapters/www_intermicrobpath/intermicrobpath.html#d0e691 there are a number of bacteria] which already interfere with the nematode’s grinder and colonize the intestine as pathogens, and that this manner of symbiosis already exists stably in other nematode/bacteria systems, as documented in [http://dx.doi.org/10.1016/j.biocontrol.2005.11.016 Ciche ''et al''. 2006], for the ultimate purpose of infecting insects with the bacteria. Ciche ''et al''. also document a number of genes required for these systems to function properly; it might be possible to transfer some of them into C. elegans and ''E. coli'' to develop a reliable cooperativity.</ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;"></ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;">The pharynx of ''C. elegans'' is far removed from most other cell lineages developmentally, and so is easy to target in terms of promoters, although our initial chassis offering focuses more on the general nervous system. The pharynx’s nearly-isolated nervous system controls pump rate, innervates the muscle cells to pump, and is consulted (along with many other sources) in establishing the dauer decision, but most other communication with the rest of the organism is probably done through hormones (see [[Team:Queens-Canada/pseudocoelom|our section on the pseudocoelom]]). Other than as a component of enterosymbiosis projects, the potential usefulness of the pharynx in synthetic biology does not appear great to us, but there are surely many possibilities we have not considered.<html></div></html></ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;"></ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;"><html><div class="section"><h2>The Intestine</h2></html></ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;"></ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;"><picture></ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;"></ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;">The intestine is a long tube that spans most of the creature’s body. It is comprised of twenty cells which form rings down the length of the worm’s interior. With the exception of the grinding activity provided by the pharynx, and defecation provided by the anus, the intestine of ''C. elegans'' performs most of the digestive functions of higher organisms, including chemical breakdown of food, absorption of nutrient molecules, and synthesis and storage of fats. For a long time, the worm’s digestive system was very poorly understood, but this is steadily being corrected in combination with knowledge of the digestive systems of other nematodes.</ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;"></ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;">The pH of the intestine is not known precisely, but studies of various catabolic enymes known to be localized to the intestinal lumen suggests that it is probably somewhere between 4 and 5. (This is much more mild than the human stomach.) As one of the greatest promises of the intestine is to create a synthetic pathway of some sort within the organ, and to use the natural excretion process to separate the product from the worm, this could potentially complicate pathways that require proteins which function optimally at higher pHs, as most do. One way around this might be to compose the product inside of the intestinal cells and then export it. The promoter and 5' UTR of ''pho-1'' [http://www.ncbi.nlm.nih.gov/pubmed/15733671|are known] to be specific only to the later end of the intestine, which could reduce the exposure time to acid, or allow for a multi-stage synthesis process that progresses down the intestine. If pH and the presence of digestive enzymes could potentially pose a threat to the safe production of some product, however, it may make more sense to move such a project into [[Team:Queens-Canada/pseudocoelom|the excretory system]] instead.</ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;"></ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;">Several of the cells in the worm’s intestine have two nuclei after the L1 stage of larval development. The purpose and value of this is not known, and preventing it by knocking out the gene ''lin-14'' does not seem to affect the worm adversely. This property may be potentially exploitable as a means to insert a foreign molecule into the nucleus before telophase begins after this superfluous division. The intestine is something of a hot spot for peculiar nucleic acid activity—[[Team:Queens-Canada/rnai|dsRNA]] is normally taken up in the intestine, through the SID-2 channel lining the lumen, and then propagates throughout the worm (except neurons) via SID-1.</ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;"></ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;">Although nematodes in general typically grind up bacteria before they reach the intestine, there are some cases in which bacteria circumvent the normal pharynx function and successfully colonize the intestinal surface, with typically detrimental effects to the host worm. Several species are known to attack ''C. elegans'' in this way, and worms particularly vulnerable to intestinal colonization due to mutations are said to be of the BUS phenotype; a family of genes has been named bus, appropriately. However, there are other nematode species where colonization isn’t doom for the worm: ''Steinernema carpocapsae'', a parasitic nematode that parasitizes wasp larvae, [http://www.ncbi.nlm.nih.gov/pubmed/17618298 forms an effective symbiosis with the bacterial species ''Xenorhabdus nematophila''], which is necessary for killing the insects and assisting the worm’s mode of reproduction.</ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;"></ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;">No immediate barrier is apparent to the thought of transferring the genes that make this colonization possible into ''C. elegans'' and ''E. coli'', although this is obviously a great deal of work, and bus mutants can most likely reproduce the effect to great success at a sufficient rate for most projects. Like the exosymbiosis suggested in the cuticle article <link>, this system of enterosymbiosis presents a great opportunity for inter-kingdom cooperation and backward compatibility with the fundamental ''E. coli'' chassis.<html></div></html></ins></div></td></tr>
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</table>Glhhttp://2010.igem.org/wiki/index.php?title=Team:Queens-Canada/digestive&diff=136048&oldid=prevGlh at 18:42, 24 October 20102010-10-24T18:42:24Z<p></p>
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</table>Glhhttp://2010.igem.org/wiki/index.php?title=Team:Queens-Canada/digestive&diff=136043&oldid=prevGlh: New page: {{:Team:Queens-Canada/head}} <h1>The Digestive System</h1> '''Continue to the Nervous System''' {{:Team:Queens-Canada/foot}}2010-10-24T18:41:58Z<p>New page: {{:Team:Queens-Canada/head}} <h1>The Digestive System</h1> '''<a href="/Team:Queens-Canada/transcripts" title="Team:Queens-Canada/transcripts">Continue to the Nervous System</a>''' {{:Team:Queens-Canada/foot}}</p>
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