{"id":{"repo_id":"ohiolink","oai_identifier":"oai:etd.ohiolink.edu:miami1364395692"},"canonical_url":"https://search.dev.ndltd.org/etd/ohiolink/oai:etd.ohiolink.edu:miami1364395692","repository":{"repo_id":"ohiolink","name":"OhioLINK","base_url":"https://etd.ohiolink.edu/acprod/odb_etd/ws/oai/oai"},"display":{"title":"Investigating Iron Transport and Utilization Features of Acinetobacter baumannii","abstract":"Acinetobacter baumannii is an important opportunistic human pathogen that causes severe nosocomial infections. The bacterium must overcome iron starvation and oxidative stress conditions imposed by the host in order to propagate and cause disease. This work further investigates the transport and utilization of iron by A. baumannii, and their involvement in virulence. The transport of iron is an active process and requires energy; A. baumannii ATCC 19606T contains and expresses three gene loci encoding functions in the TonB energy-transducing complex to provide the energy needed for iron transport. Transformation of Escherichia coli KP1344 with plasmids harboring the TonB components of these A. baumannii TonB systems promoted cell growth under iron-chelated conditions, which shows that these systems provide the necessary energy needed for iron acquisition. Inactivation of tonB1 and tonB2 in A. baumannii resulted in growth restriction under iron-chelation, indicating these genes are involved in iron transport. The Galleria mellonella infection model showed that TonB1 and TonB2 are involved, but are not essential for bacterial virulence, indicating A. baumannii carries redundant functional TonBs. Furthermore, TonB2 plays an additional role in the interaction with A549 human alveolar cells. Inactivation of dppA1A2 and dppBC, components of an inner membrane ABC transporter, did not affect growth under iron-chelation, suggesting alternative transport functions. However, inactivation of cirA, which codes for an iron-regulated outer membrane receptor resulted in reduced growth under iron-chelated conditions, indicating CirA has a role in iron transport. Furthermore, A. baumannii expresses hemin utilization functions independent of production and transport of acinetobactin-siderophore. Following transport, iron must be integrated into the intracellular iron pool. NfuA, a [Fe-S] cluster carrier protein was found to be involved in the ability of cells to respond to iron-limitation and oxidative stress, and is also needed for successful virulence in G. mellonella and within A549 cells. NfuA could be used for the maturation of intracellular [Fe-S] cluster containing proteins needed for the response to stresses encountered in the host. Taken together, the results here demonstrate that A. baumannii has implemented multiple mechanisms for the uptake and utilization of iron to ensure survival and propagation within the human host.","abstract_html":"<i>Acinetobacter baumannii</i> is an important opportunistic human pathogen that causes severe nosocomial infections. The bacterium must overcome iron starvation and oxidative stress conditions imposed by the host in order to propagate and cause disease. This work further investigates the transport and utilization of iron by <i>A. baumannii</i>, and their involvement in virulence. The transport of iron is an active process and requires energy; <i>A. baumannii</i> ATCC 19606<sup>T</sup> contains and expresses three gene loci encoding functions in the TonB energy-transducing complex to provide the energy needed for iron transport. Transformation of <i>Escherichia coli</i> KP1344 with plasmids harboring the TonB components of these <i>A. baumannii</i> TonB systems promoted cell growth under iron-chelated conditions, which shows that these systems provide the necessary energy needed for iron acquisition. Inactivation of <i>tonB</i><sub>1</sub> and <i>tonB</i><sub>2</sub> in <i>A. baumannii</i> resulted in growth restriction under iron-chelation, indicating these genes are involved in iron transport. The <i>Galleria mellonella</i> infection model showed that TonB<sub>1</sub> and TonB<sub>2</sub> are involved, but are not essential for bacterial virulence, indicating <i>A. baumannii</i> carries redundant functional TonBs. Furthermore, TonB<sub>2</sub> plays an additional role in the interaction with A549 human alveolar cells. Inactivation of <i>dppA<sub>1</sub>A<sub>2</sub></i> and <i>dppBC</i>, components of an inner membrane ABC transporter, did not affect growth under iron-chelation, suggesting alternative transport functions. However, inactivation of <i>cirA</i>, which codes for an iron-regulated outer membrane receptor resulted in reduced growth under iron-chelated conditions, indicating CirA has a role in iron transport. Furthermore, <i>A. baumannii</i> expresses hemin utilization functions independent of production and transport of acinetobactin-siderophore. Following transport, iron must be integrated into the intracellular iron pool. NfuA, a [Fe-S] cluster carrier protein was found to be involved in the ability of cells to respond to iron-limitation and oxidative stress, and is also needed for successful virulence in <i>G. mellonella</i> and within A549 cells. NfuA could be used for the maturation of intracellular [Fe-S] cluster containing proteins needed for the response to stresses encountered in the host. Taken together, the results here demonstrate that <i>A. baumannii</i> has implemented multiple mechanisms for the uptake and utilization of iron to ensure survival and propagation within the human host.","abstract_has_math":false,"creators":["Zimbler, Daniel Lawrence"],"institution":"Miami University","degree_name":"Doctor of Philosophy","degree_level":"doctoral","degree_discipline":"Microbiology","degree_department":null,"school":null,"contributors":["Actis, Luis"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2013,"date_issued":"2013-03-29","date_published":"2013-03-29","updated_at":"2026-07-24T03:37:01Z","subjects":["Microbiology","Acinetobacter baumannii","Iron Acquisition","Iron-Sulfur Cluster","Iron Regulation"],"languages":["English"],"rights":["unrestricted","This thesis or dissertation is protected by copyright: all rights reserved. It may not be copied or redistributed beyond the terms of applicable copyright laws."],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"http://rave.ohiolink.edu/etdc/view?acc_num=miami1364395692","outbound_label":"Repository record","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Actis, Luis"]},{"key":"dc:creator","label":"Author","values":["Zimbler, Daniel Lawrence"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2013-03-29"]},{"key":"dc:publisher","label":"Institution","values":["Miami University / OhioLINK"]},{"key":"dc:type","label":"Dc Type","values":["Electronic Thesis or Dissertation"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Microbiology"]},{"key":"thesis:degree_level","label":"Degree Level","values":["doctoral"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Doctor of Philosophy"]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["Miami University"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Microbiology","Acinetobacter baumannii","Iron Acquisition","Iron-Sulfur Cluster","Iron Regulation"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["English"]},{"key":"dc:rights","label":"Dc Rights","values":["unrestricted","This thesis or dissertation is protected by copyright: all rights reserved. It may not be copied or redistributed beyond the terms of applicable copyright laws."]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["http://rave.ohiolink.edu/etdc/view?acc_num=miami1364395692"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Acinetobacter baumannii is an important opportunistic human pathogen that causes severe nosocomial infections. The bacterium must overcome iron starvation and oxidative stress conditions imposed by the host in order to propagate and cause disease. This work further investigates the transport and utilization of iron by A. baumannii, and their involvement in virulence. The transport of iron is an active process and requires energy; A. baumannii ATCC 19606T contains and expresses three gene loci encoding functions in the TonB energy-transducing complex to provide the energy needed for iron transport. Transformation of Escherichia coli KP1344 with plasmids harboring the TonB components of these A. baumannii TonB systems promoted cell growth under iron-chelated conditions, which shows that these systems provide the necessary energy needed for iron acquisition. Inactivation of tonB1 and tonB2 in A. baumannii resulted in growth restriction under iron-chelation, indicating these genes are involved in iron transport. The Galleria mellonella infection model showed that TonB1 and TonB2 are involved, but are not essential for bacterial virulence, indicating A. baumannii carries redundant functional TonBs. Furthermore, TonB2 plays an additional role in the interaction with A549 human alveolar cells. Inactivation of dppA1A2 and dppBC, components of an inner membrane ABC transporter, did not affect growth under iron-chelation, suggesting alternative transport functions. However, inactivation of cirA, which codes for an iron-regulated outer membrane receptor resulted in reduced growth under iron-chelated conditions, indicating CirA has a role in iron transport. Furthermore, A. baumannii expresses hemin utilization functions independent of production and transport of acinetobactin-siderophore. Following transport, iron must be integrated into the intracellular iron pool. NfuA, a [Fe-S] cluster carrier protein was found to be involved in the ability of cells to respond to iron-limitation and oxidative stress, and is also needed for successful virulence in G. mellonella and within A549 cells. NfuA could be used for the maturation of intracellular [Fe-S] cluster containing proteins needed for the response to stresses encountered in the host. Taken together, the results here demonstrate that A. baumannii has implemented multiple mechanisms for the uptake and utilization of iron to ensure survival and propagation within the human host."]},{"key":"dc:format","label":"Dc Format","values":["application/pdf","p.180","8.37 MB"]},{"key":"dc:title","label":"Title","values":["Investigating Iron Transport and Utilization Features of Acinetobacter baumannii"]}]}],"canonical_facts":{"dc:contributor":["Actis, Luis"],"dc:creator":["Zimbler, Daniel Lawrence"],"dc:date":["2013-03-29"],"dc:description":["Acinetobacter baumannii is an important opportunistic human pathogen that causes severe nosocomial infections. The bacterium must overcome iron starvation and oxidative stress conditions imposed by the host in order to propagate and cause disease. This work further investigates the transport and utilization of iron by A. baumannii, and their involvement in virulence. The transport of iron is an active process and requires energy; A. baumannii ATCC 19606T contains and expresses three gene loci encoding functions in the TonB energy-transducing complex to provide the energy needed for iron transport. Transformation of Escherichia coli KP1344 with plasmids harboring the TonB components of these A. baumannii TonB systems promoted cell growth under iron-chelated conditions, which shows that these systems provide the necessary energy needed for iron acquisition. Inactivation of tonB1 and tonB2 in A. baumannii resulted in growth restriction under iron-chelation, indicating these genes are involved in iron transport. The Galleria mellonella infection model showed that TonB1 and TonB2 are involved, but are not essential for bacterial virulence, indicating A. baumannii carries redundant functional TonBs. Furthermore, TonB2 plays an additional role in the interaction with A549 human alveolar cells. Inactivation of dppA1A2 and dppBC, components of an inner membrane ABC transporter, did not affect growth under iron-chelation, suggesting alternative transport functions. However, inactivation of cirA, which codes for an iron-regulated outer membrane receptor resulted in reduced growth under iron-chelated conditions, indicating CirA has a role in iron transport. Furthermore, A. baumannii expresses hemin utilization functions independent of production and transport of acinetobactin-siderophore. Following transport, iron must be integrated into the intracellular iron pool. NfuA, a [Fe-S] cluster carrier protein was found to be involved in the ability of cells to respond to iron-limitation and oxidative stress, and is also needed for successful virulence in G. mellonella and within A549 cells. NfuA could be used for the maturation of intracellular [Fe-S] cluster containing proteins needed for the response to stresses encountered in the host. Taken together, the results here demonstrate that A. baumannii has implemented multiple mechanisms for the uptake and utilization of iron to ensure survival and propagation within the human host."],"dc:format":["application/pdf","p.180","8.37 MB"],"dc:identifier":["http://rave.ohiolink.edu/etdc/view?acc_num=miami1364395692"],"dc:language":["English"],"dc:publisher":["Miami University / OhioLINK"],"dc:rights":["unrestricted","This thesis or dissertation is protected by copyright: all rights reserved. It may not be copied or redistributed beyond the terms of applicable copyright laws."],"dc:subject":["Microbiology","Acinetobacter baumannii","Iron Acquisition","Iron-Sulfur Cluster","Iron Regulation"],"dc:title":["Investigating Iron Transport and Utilization Features of Acinetobacter baumannii"],"dc:type":["Electronic Thesis or Dissertation"],"thesis:degree_discipline":["Microbiology"],"thesis:degree_level":["doctoral"],"thesis:degree_name":["Doctor of Philosophy"],"thesis:institution_name":["Miami University"]},"updated_at":"2026-07-24T03:37:01Z"}