{"id":{"repo_id":"uoit","oai_identifier":"oai:ontariotechu.scholaris.ca:10155/31"},"canonical_url":"https://search.dev.ndltd.org/etd/uoit/oai:ontariotechu.scholaris.ca:10155/31","repository":{"repo_id":"uoit","name":"Ontario Institute of Technology","base_url":"https://ontariotechu.scholaris.ca/server/oai/request"},"display":{"title":"Molecular characterization of GABA receptor subunits from the parasitic nematode Haemonchus contortus","abstract":"Haemonchus contortus is a parasitic nematode that is controlled by several nematocides which target ion channels. We have identified two H. contortus ion channel genes, Hcounc- 49B and C that encode two GABA-gated chloride channel subunits. Electrophysiological analysis shows that the Hco-UNC-49B subunit forms a functional homomeric channel in Xenopus laevis oocytes that produces a robust response to GABA and is highly sensitive to picrotoxin. In contrast, Hco-UNC-49C alone does not respond to GABA but can assemble with Hco-UNC-49B to form a heteromeric channel with an increased sensitivity to GABA and a lower sensitivity to picrotoxin. To investigate the subunit requirements for high agonist sensitivity, we generated cross-assembled channels by co-expressing the H. contortus subunits with UNC-49 subunits from the nematode Caenorhabditis elegans (Cel-UNC-49). Co-expressing the Cel-UNC-49B with Hco- UNC-49C produced a heteromeric channel with a low sensitivity to GABA. In contrast, co-expressing Hco-UNC-49B with Cel-UNC-49C produced a heteromeric channel that was highly sensitive to GABA. These results suggest that the Hco-UNC-49B subunit is the key determinant for the high agonist sensitivity of heteromeric channels.","abstract_html":"Haemonchus contortus is a parasitic nematode that is controlled by several nematocides which target ion channels. We have identified two H. contortus ion channel genes, Hcounc- 49B and C that encode two GABA-gated chloride channel subunits. Electrophysiological analysis shows that the Hco-UNC-49B subunit forms a functional homomeric channel in Xenopus laevis oocytes that produces a robust response to GABA and is highly sensitive to picrotoxin. In contrast, Hco-UNC-49C alone does not respond to GABA but can assemble with Hco-UNC-49B to form a heteromeric channel with an increased sensitivity to GABA and a lower sensitivity to picrotoxin. To investigate the subunit requirements for high agonist sensitivity, we generated cross-assembled channels by co-expressing the H. contortus subunits with UNC-49 subunits from the nematode Caenorhabditis elegans (Cel-UNC-49). Co-expressing the Cel-UNC-49B with Hco- UNC-49C produced a heteromeric channel with a low sensitivity to GABA. In contrast, co-expressing Hco-UNC-49B with Cel-UNC-49C produced a heteromeric channel that was highly sensitive to GABA. These results suggest that the Hco-UNC-49B subunit is the key determinant for the high agonist sensitivity of heteromeric channels.","abstract_has_math":false,"creators":["Siddiqui, Salma"],"institution":"University of Ontario Institute of Technology","degree_name":"Master of Science (MSc)","degree_level":null,"degree_discipline":"Applied Bioscience","degree_department":null,"school":null,"contributors":[],"advisors":["Forrester, Sean","Bonetta, Dario"],"committee_chairs":[],"committee_members":[],"year":2009,"date_issued":"2009-08-01","date_published":"2009-08-01","updated_at":"2026-07-24T05:35:18Z","subjects":["GABA","Ligand-gated chloride channel","Electrophysiology","Homomeric channel","Haemonchus contortus","Heteromeric channel"],"languages":["en"],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://hdl.handle.net/10155/31","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.advisor","label":"Advisor","values":["Forrester, Sean","Bonetta, Dario"]},{"key":"dc:creator","label":"Author","values":["Siddiqui, Salma"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2009-10-09T19:17:30Z","2022-03-29T17:06:26Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2009-10-09T19:17:30Z","2022-03-29T17:06:26Z"]},{"key":"dc:date.issued","label":"Date","values":["2009-08-01"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Applied Bioscience"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Master of Science (MSc)"]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["University of Ontario Institute of Technology"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["GABA","Ligand-gated chloride channel","Electrophysiology","Homomeric channel","Haemonchus contortus","Heteromeric channel"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language.iso","label":"Language (ISO)","values":["en"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.uri","label":"Identifier URI","values":["https://hdl.handle.net/10155/31"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["Haemonchus contortus is a parasitic nematode that is controlled by several nematocides which target ion channels. We have identified two H. contortus ion channel genes, Hcounc- 49B and C that encode two GABA-gated chloride channel subunits. Electrophysiological analysis shows that the Hco-UNC-49B subunit forms a functional homomeric channel in Xenopus laevis oocytes that produces a robust response to GABA and is highly sensitive to picrotoxin. In contrast, Hco-UNC-49C alone does not respond to GABA but can assemble with Hco-UNC-49B to form a heteromeric channel with an increased sensitivity to GABA and a lower sensitivity to picrotoxin. To investigate the subunit requirements for high agonist sensitivity, we generated cross-assembled channels by co-expressing the H. contortus subunits with UNC-49 subunits from the nematode Caenorhabditis elegans (Cel-UNC-49). Co-expressing the Cel-UNC-49B with Hco- UNC-49C produced a heteromeric channel with a low sensitivity to GABA. In contrast, co-expressing Hco-UNC-49B with Cel-UNC-49C produced a heteromeric channel that was highly sensitive to GABA. These results suggest that the Hco-UNC-49B subunit is the key determinant for the high agonist sensitivity of heteromeric channels."]},{"key":"dc:title","label":"Title","values":["Molecular characterization of GABA receptor subunits from the parasitic nematode Haemonchus contortus"]}]}],"canonical_facts":{"dc:contributor.advisor":["Forrester, Sean","Bonetta, Dario"],"dc:creator":["Siddiqui, Salma"],"dc:date.accessioned":["2009-10-09T19:17:30Z","2022-03-29T17:06:26Z"],"dc:date.available":["2009-10-09T19:17:30Z","2022-03-29T17:06:26Z"],"dc:date.issued":["2009-08-01"],"dc:description.abstract":["Haemonchus contortus is a parasitic nematode that is controlled by several nematocides which target ion channels. We have identified two H. contortus ion channel genes, Hcounc- 49B and C that encode two GABA-gated chloride channel subunits. Electrophysiological analysis shows that the Hco-UNC-49B subunit forms a functional homomeric channel in Xenopus laevis oocytes that produces a robust response to GABA and is highly sensitive to picrotoxin. In contrast, Hco-UNC-49C alone does not respond to GABA but can assemble with Hco-UNC-49B to form a heteromeric channel with an increased sensitivity to GABA and a lower sensitivity to picrotoxin. To investigate the subunit requirements for high agonist sensitivity, we generated cross-assembled channels by co-expressing the H. contortus subunits with UNC-49 subunits from the nematode Caenorhabditis elegans (Cel-UNC-49). Co-expressing the Cel-UNC-49B with Hco- UNC-49C produced a heteromeric channel with a low sensitivity to GABA. In contrast, co-expressing Hco-UNC-49B with Cel-UNC-49C produced a heteromeric channel that was highly sensitive to GABA. These results suggest that the Hco-UNC-49B subunit is the key determinant for the high agonist sensitivity of heteromeric channels."],"dc:identifier.uri":["https://hdl.handle.net/10155/31"],"dc:language.iso":["en"],"dc:subject":["GABA","Ligand-gated chloride channel","Electrophysiology","Homomeric channel","Haemonchus contortus","Heteromeric channel"],"dc:title":["Molecular characterization of GABA receptor subunits from the parasitic nematode Haemonchus contortus"],"dc:type":["Thesis"],"thesis:degree_discipline":["Applied Bioscience"],"thesis:degree_name":["Master of Science (MSc)"],"thesis:institution_name":["University of Ontario Institute of Technology"]},"updated_at":"2026-07-24T05:35:18Z"}