@article{weingarten_taveirne_olson_2009, title={The Dual-Functioning Fumarate Reductase Is the Sole Succinate: Quinone Reductase in Campylobacter jejuni and Is Required for Full Host Colonization}, volume={191}, ISSN={["1098-5530"]}, DOI={10.1128/JB.00166-09}, abstractNote={ABSTRACT
          
            Campylobacter jejuni
            encodes all the enzymes necessary for a complete oxidative tricarboxylic acid (TCA) cycle. Because of its inability to utilize glucose,
            C. jejuni
            relies exclusively on amino acids as the source of reduced carbon, and they are incorporated into central carbon metabolism. The oxidation of succinate to fumarate is a key step in the oxidative TCA cycle.
            C. jejuni
            encodes enzymes annotated as a fumarate reductase (Cj0408 to Cj0410) and a succinate dehydrogenase (Cj0437 to Cj0439). Null alleles in the genes encoding each enzyme were constructed. Both enzymes contributed to the total fumarate reductase activity in vitro. The
            frdA
            ::
            cat
            +
            strain was completely deficient in succinate dehydrogenase activity in vitro and was unable to perform whole-cell succinate-dependent respiration. The
            sdhA
            ::
            cat
            +
            strain exhibited wild-type levels of succinate dehydrogenase activity both in vivo and in vitro. These data indicate that Frd is the only succinate dehydrogenase in
            C. jejuni
            and that the protein annotated as a succinate dehydrogenase has been misannotated. The
            frdA
            ::
            cat
            +
            strain was also unable to grow with the characteristic wild-type biphasic growth pattern and exhibited only the first growth phase, which is marked by the consumption of aspartate, serine, and associated organic acids. Substrates consumed in the second growth phase (glutamate, proline, and associated organic acids) were not catabolized by the the
            frdA
            ::
            cat
            +
            strain, indicating that the oxidation of succinate is a crucial step in metabolism of these substrates. Chicken colonization trials confirmed the in vivo importance of succinate oxidation, as the
            frdA
            ::
            cat
            +
            strain colonized chickens at significantly lower levels than the wild type, while the
            sdhA
            ::
            cat
            +
            strain colonized chickens at wild-type levels.
          }, number={16}, journal={JOURNAL OF BACTERIOLOGY}, author={Weingarten, Rebecca A. and Taveirne, Michael E. and Olson, Jonathan W.}, year={2009}, month={Aug}, pages={5293–5300} }
 @article{weingarten_grimes_olson_2008, title={Role of Campylobacter jejuni respiratory oxidases and reductases in host colonization}, volume={74}, ISSN={["0099-2240"]}, DOI={10.1128/AEM.02261-07}, abstractNote={ABSTRACT
          
            Campylobacter jejuni
            is the leading cause of human food-borne bacterial gastroenteritis. The
            C. jejuni
            genome sequence predicts a branched electron transport chain capable of utilizing multiple electron acceptors. Mutants were constructed by disrupting the coding regions of the respiratory enzymes nitrate reductase (
            napA
            ::Cm), nitrite reductase (
            nrfA
            ::Cm), dimethyl sulfoxide, and trimethylamine
            N
            -oxide reductase (termed Cj0264::Cm) and the two terminal oxidases, a cyanide-insensitive oxidase (
            cydA
            ::Cm) and
            cbb3
            -type oxidase (
            ccoN
            ::Cm). Each strain was characterized for the loss of the associated enzymatic function in vitro. The strains were then inoculated into 1-week-old chicks, and the cecal contents were assayed for the presence of
            C. jejuni
            2 weeks postinoculation.
            cydA
            ::Cm and Cj0264c::Cm strains colonized as well as the wild type;
            napA
            ::Cm and
            nrfA
            ::Cm strains colonized at levels significantly lower than the wild type. The
            ccoN
            ::Cm strain was unable to colonize the chicken; no colonies were recovered at the end of the experiment. While there appears to be a role for anaerobic respiration in host colonization, oxygen is the most important respiratory acceptor for
            C. jejuni
            in the chicken cecum.
          }, number={5}, journal={APPLIED AND ENVIRONMENTAL MICROBIOLOGY}, author={Weingarten, Rebecca A. and Grimes, Jesse L. and Olson, Jonathan W.}, year={2008}, month={Mar}, pages={1367–1375} }