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dc.contributor.advisorH. Robert Horvitz.en_US
dc.contributor.authorOmura, Daniel Togoen_US
dc.contributor.otherMassachusetts Institute of Technology. Dept. of Biology.en_US
dc.date.accessioned2008-12-11T16:55:51Z
dc.date.available2008-12-11T16:55:51Z
dc.date.copyright2008en_US
dc.date.issued2008en_US
dc.identifier.urihttp://hdl.handle.net/1721.1/43734
dc.descriptionThesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Biology, 2008.en_US
dc.descriptionThis electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.en_US
dc.descriptionIncludes bibliographical references.en_US
dc.description.abstractIn the presence of a bacterial food source, the small nematode C. elegans greatly reduces its rate of locomotion. While mechanical agitation greatly stimulates the locomotion of well-fed animals on bacteria, it does not greatly stimulate the locomotion of food-deprived animals on bacteria. Thus, the competing effects of food and mechanical agitation on the animal's locomotory behavior are modulated by food deprivation. To explore how C. elegans modulates its locomotion we focused on determining how C. elegans detects bacteria, and explored the roles of biogenic amines, metabolic, and stress signaling pathways on this behavior. We correlated specific sensory defects and the expression patterns of genes involved in sensory function, gathered by the community of C. elegans researchers, with abnormal responses to a bacterial food source. Our findings suggest that a soluble component of the bacterial lawn is detected by the ASH and ASE chemosensory neurons and acts to suppress locomotion, while a volatile component of the bacterial lawn is redundantly detected by multiple chemosensory neurons and acts to maintain or stimulate locomotion on bacteria. In collaboration with Damon Clark and Aravi Samuel at Harvard University, we developed an automated locomotion tracking system that greatly improves the resolution at which we can study C. elegans locomotion. Using this system, we uncovered excitatory and inhibitory effects of serotonin on C. elegans locomotion and found that serotonin, dopamine, octopamine, and tyramine regulate the actions of one another. We also found that dopamine is required to set and maintain a precise rate of locomotion by C. elegans.en_US
dc.description.abstract(cont.) We observed that mutants defective in dopamine signaling make crude adjustments to their speeds that result in large fluctuations in their rates of locomotion. Treatment of dopamine deficient mutants with exogenous dopamine completely rescues these locomotion defects. Removal of tyramine and octopamine together partially suppressed these defects. We also studied how food-deprivation changes the animal's response to bacteria and mechanical agitation. We found that presumptive metabolic signaling through the C. elegans insulin receptor homolog daf-2 and stress signaling through octopamine converge on the neuropeptide Y receptor homolog npr-1 to modulate the animal's responses to food, mechanical agitation, and food-deprivation.en_US
dc.description.statementofresponsibilityDaniel Togo Omura.en_US
dc.format.extent269 p.en_US
dc.language.isoengen_US
dc.publisherMassachusetts Institute of Technologyen_US
dc.rightsM.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.en_US
dc.rights.urihttp://dspace.mit.edu/handle/1721.1/7582en_US
dc.subjectBiology.en_US
dc.titleC. elegans integrates food, stress, and hunger signals to coordinate motor activityen_US
dc.title.alternativeCerevisiae elegans integrates food, stress, and hunger signals to coordinate motor activityen_US
dc.typeThesisen_US
dc.description.degreePh.D.en_US
dc.contributor.departmentMassachusetts Institute of Technology. Dept. of Biology.en_US
dc.identifier.oclc261339335en_US


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