{"id":{"repo_id":"vt","oai_identifier":"oai:vtechworks.lib.vt.edu:10919/25975"},"canonical_url":"https://search.dev.ndltd.org/etd/vt/oai:vtechworks.lib.vt.edu:10919/25975","repository":{"repo_id":"vt","name":"Virginia Tech","base_url":"https://vtechworks.lib.vt.edu/oai/request"},"display":{"title":"Evaluation of Anion Transporters as Potential Target Sites for Insect and Nematode Control: Toxicological, Electrophysiological, and Molecular Studies","abstract":"In this study, four anion transporter (AT) blockers, DIDS (4, 4′-diisothiocyanatostilbene-2, 2′-disulfonic acid), 9-AC (anthracene-9-carboxylic acid), NPPB (5-nitro-2-(3-phenylpropylamino) benzoic acid), and IAA-94 (indanyloxy acetic acid) were selected to evaluate ATs as potential target sites for insect and nematode control. All the AT blockers showed slowly developing toxicity against second-stage larvae of <i>Meloidogyne incognita</i> (Kofoid and White 1919) Chitwood 1949 and adults of <i>Caenorhabditis elegans</i> Maupas 1900 but not against third-stage larvae of <i>Heterorhabditis bacteriophora</i> Poinar 1975 even at 200 ppm. Symptoms of AT blocker toxicity observed in <i>C. elegans</i> adults were increased pharyngeal muscle contractions and decreased locomotion. Exposure of <i>C. elegans</i> as fourth-stage larvae to double-stranded RNA (dsRNA) of <i>ceclc-1</i> and <i>ceclc-2</i> (VGCC genes coding for CeClC-1 and CeClC-2, respectively) either alone or together for 24 h decreased their expression in F1 progeny in a time-dependent manner. Reduction in expression of <i>ceclc-2</i> alone or together with <i>ceclc-1</i> significantly increased pharyngeal contractions and decreased locomotion in significantly higher percentage of F1 progeny. The above findings suggested AT blockers nematicidal activity primarily comes from inhibition of CeClC-2 channels, while inhibition of CeClC-1 channels may enhance this activity. All the AT blockers showed slowly developing toxicity against adults of a susceptible strain (Oregon-R) of <i>Drosophila melanogaster</i> Meigen 1830, while DIDS, was equally toxic to dieldrin-resistant rdl flies. All AT blockers, except 9-AC, at 100 µM showed significant excitatory effect on desheathed central nervous system (CNS) of third-instar larvae of <i>Drosophila</i>, while DIDS showed a modest excitatory effect on ascending peripheral nerves. Feeding adult flies on 10% sugar solution mixed with 100 ppm of DIDS for 6 h decreased the midgut pH by 2 units approximately. All the AT blockers inhibited the growth of larvae (in weight), increased the developmental time, and decreased survival when <i>Ostrinia nubilalis</i> (Hübner 1796) second-instar larvae were fed for seven days. All the AT blockers decreased the midgut alkalinity and inhibited chloride ion transport from midgut lumen into epithelia in fifth-instar larvae when fed for 3 h on treated diet. Positive correlations observed among growth, midgut alkalinity, and midgut chloride transport in AT blocker-fed larvae suggested that inhibition of chloride/bicarbonate exchangers by AT blockers may have contributed to midgut alkalinity decrease affecting the digestion and resulting in observed lethal and sublethal effects.","abstract_html":"In this study, four anion transporter (AT) blockers, DIDS (4, 4′-diisothiocyanatostilbene-2, 2′-disulfonic acid), 9-AC (anthracene-9-carboxylic acid), NPPB (5-nitro-2-(3-phenylpropylamino) benzoic acid), and IAA-94 (indanyloxy acetic acid) were selected to evaluate ATs as potential target sites for insect and nematode control. All the AT blockers showed slowly developing toxicity against second-stage larvae of &lt;i&gt;Meloidogyne incognita&lt;/i&gt; (Kofoid and White 1919) Chitwood 1949 and adults of &lt;i&gt;Caenorhabditis elegans&lt;/i&gt; Maupas 1900 but not against third-stage larvae of &lt;i&gt;Heterorhabditis bacteriophora&lt;/i&gt; Poinar 1975 even at 200 ppm. Symptoms of AT blocker toxicity observed in &lt;i&gt;C. elegans&lt;/i&gt; adults were increased pharyngeal muscle contractions and decreased locomotion. Exposure of &lt;i&gt;C. elegans&lt;/i&gt; as fourth-stage larvae to double-stranded RNA (dsRNA) of &lt;i&gt;ceclc-1&lt;/i&gt; and &lt;i&gt;ceclc-2&lt;/i&gt; (VGCC genes coding for CeClC-1 and CeClC-2, respectively) either alone or together for 24 h decreased their expression in F1 progeny in a time-dependent manner. Reduction in expression of &lt;i&gt;ceclc-2&lt;/i&gt; alone or together with &lt;i&gt;ceclc-1&lt;/i&gt; significantly increased pharyngeal contractions and decreased locomotion in significantly higher percentage of F1 progeny. The above findings suggested AT blockers nematicidal activity primarily comes from inhibition of CeClC-2 channels, while inhibition of CeClC-1 channels may enhance this activity. All the AT blockers showed slowly developing toxicity against adults of a susceptible strain (Oregon-R) of &lt;i&gt;Drosophila melanogaster&lt;/i&gt; Meigen 1830, while DIDS, was equally toxic to dieldrin-resistant rdl flies. All AT blockers, except 9-AC, at 100 µM showed significant excitatory effect on desheathed central nervous system (CNS) of third-instar larvae of &lt;i&gt;Drosophila&lt;/i&gt;, while DIDS showed a modest excitatory effect on ascending peripheral nerves. Feeding adult flies on 10% sugar solution mixed with 100 ppm of DIDS for 6 h decreased the midgut pH by 2 units approximately. All the AT blockers inhibited the growth of larvae (in weight), increased the developmental time, and decreased survival when &lt;i&gt;Ostrinia nubilalis&lt;/i&gt; (Hübner 1796) second-instar larvae were fed for seven days. All the AT blockers decreased the midgut alkalinity and inhibited chloride ion transport from midgut lumen into epithelia in fifth-instar larvae when fed for 3 h on treated diet. Positive correlations observed among growth, midgut alkalinity, and midgut chloride transport in AT blocker-fed larvae suggested that inhibition of chloride/bicarbonate exchangers by AT blockers may have contributed to midgut alkalinity decrease affecting the digestion and resulting in observed lethal and sublethal effects.","abstract_has_math":false,"creators":["Boina, Dhana Raj"],"institution":"Virginia Tech","degree_name":"Ph. D.","degree_level":"doctoral","degree_discipline":"Entomology","degree_department":"Entomology","school":null,"contributors":[],"advisors":[],"committee_chairs":["Bloomquist, Jeffrey R."],"committee_members":["Lewis, Edwin E.","Wong, Eric E.","Mullins, Donald E.","Eisenback, Jonathan D."],"year":2008,"date_issued":"2008-01-03","date_published":"2008-01-03","updated_at":"2026-07-24T05:56:39Z","subjects":["neurophysiological activity","IAA-94","9-AC","NPPB","DIDS","chloride/bicarbonate exchangers","Voltage-gated chloride channels","RNA interference"],"languages":[],"rights":["In Copyright"],"rights_urls":["http://rightsstatements.org/vocab/InC/1.0/"],"identifier_entries":[{"key":"dc:identifier.other","label":"Dc Identifier Other","values":["etd-01092008-154304"],"render_values":[{"text":"etd-01092008-154304","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/10919/25975","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.committeechair","label":"Committee Chair","values":["Bloomquist, Jeffrey R."]},{"key":"dc:contributor.committeemember","label":"Committee Member","values":["Lewis, Edwin E.","Wong, Eric E.","Mullins, Donald E.","Eisenback, Jonathan D."]},{"key":"dc:contributor.department","label":"Department","values":["Entomology"]},{"key":"dc:creator","label":"Author","values":["Boina, Dhana Raj"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2014-03-14T20:06:40Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2014-03-14T20:06:40Z","2008-01-31"]},{"key":"dc:date.issued","label":"Date","values":["2008-01-03"]},{"key":"dc:publisher","label":"Institution","values":["Virginia Tech"]},{"key":"dc:type","label":"Dc Type","values":["Dissertation"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Entomology"]},{"key":"thesis:degree_level","label":"Degree Level","values":["doctoral"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Ph. 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All the AT blockers showed slowly developing toxicity against second-stage larvae of <i>Meloidogyne incognita</i> (Kofoid and White 1919) Chitwood 1949 and adults of <i>Caenorhabditis elegans</i> Maupas 1900 but not against third-stage larvae of <i>Heterorhabditis bacteriophora</i> Poinar 1975 even at 200 ppm. Symptoms of AT blocker toxicity observed in <i>C. elegans</i> adults were increased pharyngeal muscle contractions and decreased locomotion. Exposure of <i>C. elegans</i> as fourth-stage larvae to double-stranded RNA (dsRNA) of <i>ceclc-1</i> and <i>ceclc-2</i> (VGCC genes coding for CeClC-1 and CeClC-2, respectively) either alone or together for 24 h decreased their expression in F1 progeny in a time-dependent manner. Reduction in expression of <i>ceclc-2</i> alone or together with <i>ceclc-1</i> significantly increased pharyngeal contractions and decreased locomotion in significantly higher percentage of F1 progeny. The above findings suggested AT blockers nematicidal activity primarily comes from inhibition of CeClC-2 channels, while inhibition of CeClC-1 channels may enhance this activity. All the AT blockers showed slowly developing toxicity against adults of a susceptible strain (Oregon-R) of <i>Drosophila melanogaster</i> Meigen 1830, while DIDS, was equally toxic to dieldrin-resistant rdl flies. All AT blockers, except 9-AC, at 100 µM showed significant excitatory effect on desheathed central nervous system (CNS) of third-instar larvae of <i>Drosophila</i>, while DIDS showed a modest excitatory effect on ascending peripheral nerves. Feeding adult flies on 10% sugar solution mixed with 100 ppm of DIDS for 6 h decreased the midgut pH by 2 units approximately. All the AT blockers inhibited the growth of larvae (in weight), increased the developmental time, and decreased survival when <i>Ostrinia nubilalis</i> (Hübner 1796) second-instar larvae were fed for seven days. All the AT blockers decreased the midgut alkalinity and inhibited chloride ion transport from midgut lumen into epithelia in fifth-instar larvae when fed for 3 h on treated diet. Positive correlations observed among growth, midgut alkalinity, and midgut chloride transport in AT blocker-fed larvae suggested that inhibition of chloride/bicarbonate exchangers by AT blockers may have contributed to midgut alkalinity decrease affecting the digestion and resulting in observed lethal and sublethal effects."]},{"key":"dc:description.degree","label":"Dc Description Degree","values":["Ph. D."]},{"key":"dc:title","label":"Title","values":["Evaluation of Anion Transporters as Potential Target Sites for Insect and Nematode Control: Toxicological, Electrophysiological, and Molecular Studies"]}]}],"canonical_facts":{"dc:contributor.committeechair":["Bloomquist, Jeffrey R."],"dc:contributor.committeemember":["Lewis, Edwin E.","Wong, Eric E.","Mullins, Donald E.","Eisenback, Jonathan D."],"dc:contributor.department":["Entomology"],"dc:creator":["Boina, Dhana Raj"],"dc:date.accessioned":["2014-03-14T20:06:40Z"],"dc:date.available":["2014-03-14T20:06:40Z","2008-01-31"],"dc:date.issued":["2008-01-03"],"dc:description.abstract":["In this study, four anion transporter (AT) blockers, DIDS (4, 4′-diisothiocyanatostilbene-2, 2′-disulfonic acid), 9-AC (anthracene-9-carboxylic acid), NPPB (5-nitro-2-(3-phenylpropylamino) benzoic acid), and IAA-94 (indanyloxy acetic acid) were selected to evaluate ATs as potential target sites for insect and nematode control. All the AT blockers showed slowly developing toxicity against second-stage larvae of <i>Meloidogyne incognita</i> (Kofoid and White 1919) Chitwood 1949 and adults of <i>Caenorhabditis elegans</i> Maupas 1900 but not against third-stage larvae of <i>Heterorhabditis bacteriophora</i> Poinar 1975 even at 200 ppm. Symptoms of AT blocker toxicity observed in <i>C. elegans</i> adults were increased pharyngeal muscle contractions and decreased locomotion. Exposure of <i>C. elegans</i> as fourth-stage larvae to double-stranded RNA (dsRNA) of <i>ceclc-1</i> and <i>ceclc-2</i> (VGCC genes coding for CeClC-1 and CeClC-2, respectively) either alone or together for 24 h decreased their expression in F1 progeny in a time-dependent manner. Reduction in expression of <i>ceclc-2</i> alone or together with <i>ceclc-1</i> significantly increased pharyngeal contractions and decreased locomotion in significantly higher percentage of F1 progeny. The above findings suggested AT blockers nematicidal activity primarily comes from inhibition of CeClC-2 channels, while inhibition of CeClC-1 channels may enhance this activity. All the AT blockers showed slowly developing toxicity against adults of a susceptible strain (Oregon-R) of <i>Drosophila melanogaster</i> Meigen 1830, while DIDS, was equally toxic to dieldrin-resistant rdl flies. All AT blockers, except 9-AC, at 100 µM showed significant excitatory effect on desheathed central nervous system (CNS) of third-instar larvae of <i>Drosophila</i>, while DIDS showed a modest excitatory effect on ascending peripheral nerves. Feeding adult flies on 10% sugar solution mixed with 100 ppm of DIDS for 6 h decreased the midgut pH by 2 units approximately. All the AT blockers inhibited the growth of larvae (in weight), increased the developmental time, and decreased survival when <i>Ostrinia nubilalis</i> (Hübner 1796) second-instar larvae were fed for seven days. All the AT blockers decreased the midgut alkalinity and inhibited chloride ion transport from midgut lumen into epithelia in fifth-instar larvae when fed for 3 h on treated diet. Positive correlations observed among growth, midgut alkalinity, and midgut chloride transport in AT blocker-fed larvae suggested that inhibition of chloride/bicarbonate exchangers by AT blockers may have contributed to midgut alkalinity decrease affecting the digestion and resulting in observed lethal and sublethal effects."],"dc:description.degree":["Ph. D."],"dc:identifier.other":["etd-01092008-154304"],"dc:identifier.uri":["http://hdl.handle.net/10919/25975"],"dc:publisher":["Virginia Tech"],"dc:rights":["In Copyright"],"dc:rights.uri":["http://rightsstatements.org/vocab/InC/1.0/"],"dc:subject":["neurophysiological activity","IAA-94","9-AC","NPPB","DIDS","chloride/bicarbonate exchangers","Voltage-gated chloride channels","RNA interference"],"dc:title":["Evaluation of Anion Transporters as Potential Target Sites for Insect and Nematode Control: Toxicological, Electrophysiological, and Molecular Studies"],"dc:type":["Dissertation"],"thesis:degree_discipline":["Entomology"],"thesis:degree_level":["doctoral"],"thesis:degree_name":["Ph. D."],"thesis:institution_name":["Virginia Polytechnic Institute and State University"]},"updated_at":"2026-07-24T05:56:39Z"}