Document Type


Date of Degree

Summer 2014

Degree Name

PhD (Doctor of Philosophy)

Degree In


First Advisor

Kirby, John R

First Committee Member

Clegg, Steven

Second Committee Member

Yahr, Timothy

Third Committee Member

Ellermeier, Craig D

Fourth Committee Member

Fuentes, Ernesto J


Bacterial physiology and behavior is controlled by complex regulatory networks. Chemosensory systems are sophisticated signal transduction systems that can govern a range of cellular functions beyond that of traditional flagellar-based chemotaxis. The soil bacterium Myxococcus xanthus encodes eight chemosensory systems regulating multiple behaviors, including motility, exopolysaccharide production, and development. This work characterizes the Che7 system and demonstrates a role for Che7 in coupling aggregation and sporulation during multicellular development. The regulation requires an interaction between a single domain response regulator (CheY7) and a HEAT-repeat protein (Cpc7). A fatty acid desaturase, Des7, also impacts development in concert with the Che7 signaling system. Genetic analysis indicates the target of Che7 regulation is in the heme biosynthesis pathway, which is one aspect of iron homeostasis. Finally, characterization of iron and iron-responsive elements during development reveal a novel regulator, Fur2, that controls timing of development as well as che7 transcription. This work provides expands the known network regulating development in M. xanthus.


Chemosensory, Heme, Myxococcus, Signal transduction


xi, 140 pages


Includes bibliographical references (pages 116-124).


Copyright 2014 Cynthia Lynn Darnell

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Microbiology Commons