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http://hdl.handle.net/11375/11316
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DC Field | Value | Language |
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dc.contributor.advisor | O`Donnell, Michael | en_US |
dc.contributor.advisor | Wood, Chris | en_US |
dc.contributor.advisor | Wood, Chris | en_US |
dc.contributor.author | Belowitz, Ryan F. | en_US |
dc.date.accessioned | 2014-06-18T16:54:16Z | - |
dc.date.available | 2014-06-18T16:54:16Z | - |
dc.date.created | 2011-09-26 | en_US |
dc.date.issued | 2011-10 | en_US |
dc.identifier.other | opendissertations/6293 | en_US |
dc.identifier.other | 7300 | en_US |
dc.identifier.other | 2259139 | en_US |
dc.identifier.uri | http://hdl.handle.net/11375/11316 | - |
dc.description.abstract | <p>Tl<sup>+</sup> is thought to be toxic to cells due to ionic mimicry of K<sup>+</sup>. The aims of this study were two-fold. First, to identify whether K<sup>+</sup> and Tl<sup>+</sup> were interacting in isolated guts, whole animals and tissues in <em>Chironomus riparius, </em>and second, to determine the strategies of Tl<sup>+</sup> tolerance. <em>C. riparius. </em>were very tolerant towards Tl<sup>+ </sup>with a 48-hr LC<sub>50</sub> of 723 μmol l<sup>-1</sup>. The Scanning Ion-selective Technique (SIET) allowed us to identify the caecae, AMG and PMG as the major K<sup>+</sup>-transporting regions of isolated guts. Evidence for an interaction was based on the finding that Tl<sup>+</sup> was transported in the same directions at these segments (and others), and that 50 μmol l<sup>-1 </sup>Tl<sup>+</sup> decreased K<sup>+</sup> flux at the AMG and PMG. In addition, exposure to Tl<sup>+</sup> prior to flux measurements had significant effects on net K<sup>+</sup> transport by the gut. Measurements of Tl<sup>+</sup> and K<sup>+</sup> concentrations in the whole animal, gut and hemolymph by Atomic Absorption Spectroscopy (AAS) indicated that Tl<sup>+</sup> uptake was saturable in the whole animal and gut, and non-saturable in the hemolymph. Together with the SIET measurements, the AAS data suggests that high levels of Tl<sup>+</sup> can perturb K<sup>+</sup> transport and homeostasis. The absorption of Tl<sup>+</sup> from the gut to hemolymph, measured by SIET, was confirmed by hemolymph measurements of Tl<sup>+</sup> using AAS. This indicated that Tl<sup>+</sup> gains access to the hemolymph and that sensitive tissues (such as the nervous system) are thus exposed. However, survival of <em>C. riparius</em> at these concentrations implies efficient mechanisms for detoxification of Tl<sup>+</sup>. This tolerance may involve sequestration in the gut, metal-binding proteins and increased secretion by the anal papillae and MTs. In addition, loss of K<sup>+</sup> from the muscle may prevent hypokalemia in the hemolymph and gut.</p> | en_US |
dc.subject | Thallium | en_US |
dc.subject | Potassium | en_US |
dc.subject | Chironomus riparius | en_US |
dc.subject | Tl2+-selective microelectrodes | en_US |
dc.subject | Tl tolerance | en_US |
dc.subject | ion transport | en_US |
dc.subject | SIET | en_US |
dc.subject | Biology | en_US |
dc.subject | Other Pharmacology, Toxicology and Environmental Health | en_US |
dc.subject | Other Physiology | en_US |
dc.subject | Toxicology | en_US |
dc.subject | Biology | en_US |
dc.title | INVESTIGATIONS OF THE INTERACTIONS BETWEEN K+ AND Tl+ IN CHIRONOMUS RIPARIUS LARVAE | en_US |
dc.type | thesis | en_US |
dc.contributor.department | Biology | en_US |
dc.description.degree | Master of Science (MSc) | en_US |
Appears in Collections: | Open Access Dissertations and Theses |
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fulltext.pdf | 1.1 MB | Adobe PDF | View/Open |
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