Studies on the Regulation of the Assimilatory Nitrate Reductase Operon in Azotobacter vinelandii

Persistent Link:
http://hdl.handle.net/10150/195085
Title:
Studies on the Regulation of the Assimilatory Nitrate Reductase Operon in Azotobacter vinelandii
Author:
Wang, Baomin
Issue Date:
2009
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
Azotobacter vinelandii is a free-living diazotroph. This bacterium fixes atmospheric nitrogen in different environments using three genetically distinct nitrogenases. A. vinelandii is also capable of utilizing nitrate and nitrite from the environment. Nitrate is reduced sequentially into nitrite and ammonia. The assimilatory nitrate reductase and nitrite reductase are encoded by the nasAB operon. Previous genetic studies identified a number of factors that influence nasAB expression. However, the molecular mechanisms controlling the expression of nasAB are unclear.The current study was initiated to characterize the region preceding the nasAB operon which was previously implicated in its regulation and to further study the molecular mechanisms of nasAB regulation. The results confirm that nasAB is subject to multiple layers of regulation. The operon is under the control of an NtrC-dependent promoter; nitrate/nitrite induction occurs at the post-transcriptional level via antitermination within the nasAB leader region; and nitrate/nitrite induction is mediated by NasS/NasT, a sensor-antiterminator two-component regulatory system.Together, these data suggest a model for the regulation of the assimilatory nitrate reductase operon in A. vinelandii.
Type:
text; Electronic Dissertation
Keywords:
Antitermination; Azotobacter vinelandii; Nitrate reductase; Regulation
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Plant Pathology; Graduate College
Degree Grantor:
University of Arizona
Advisor:
Pierson III, Leland S.
Committee Chair:
Pierson III, Leland S.

Full metadata record

DC FieldValue Language
dc.language.isoENen_US
dc.titleStudies on the Regulation of the Assimilatory Nitrate Reductase Operon in Azotobacter vinelandiien_US
dc.creatorWang, Baominen_US
dc.contributor.authorWang, Baominen_US
dc.date.issued2009en_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractAzotobacter vinelandii is a free-living diazotroph. This bacterium fixes atmospheric nitrogen in different environments using three genetically distinct nitrogenases. A. vinelandii is also capable of utilizing nitrate and nitrite from the environment. Nitrate is reduced sequentially into nitrite and ammonia. The assimilatory nitrate reductase and nitrite reductase are encoded by the nasAB operon. Previous genetic studies identified a number of factors that influence nasAB expression. However, the molecular mechanisms controlling the expression of nasAB are unclear.The current study was initiated to characterize the region preceding the nasAB operon which was previously implicated in its regulation and to further study the molecular mechanisms of nasAB regulation. The results confirm that nasAB is subject to multiple layers of regulation. The operon is under the control of an NtrC-dependent promoter; nitrate/nitrite induction occurs at the post-transcriptional level via antitermination within the nasAB leader region; and nitrate/nitrite induction is mediated by NasS/NasT, a sensor-antiterminator two-component regulatory system.Together, these data suggest a model for the regulation of the assimilatory nitrate reductase operon in A. vinelandii.en_US
dc.typetexten_US
dc.typeElectronic Dissertationen_US
dc.subjectAntiterminationen_US
dc.subjectAzotobacter vinelandiien_US
dc.subjectNitrate reductaseen_US
dc.subjectRegulationen_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplinePlant Pathologyen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorPierson III, Leland S.en_US
dc.contributor.chairPierson III, Leland S.en_US
dc.contributor.committeememberFane, Bentley A.en_US
dc.contributor.committeememberRensing, Christopher G.en_US
dc.contributor.committeememberOrbach, Marc J.en_US
dc.identifier.proquest10388en_US
dc.identifier.oclc659752138en_US
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