@article{hanafy_osborne_miller_parker_olson_jackson_kathariou_2022, title={Differences in the Propensity of Different Antimicrobial Resistance Determinants to Be Disseminated via Transformation in Campylobacter jejuni and Campylobacter coli}, volume={10}, ISSN={["2076-2607"]}, DOI={10.3390/microorganisms10061194}, abstractNote={Campylobacter jejuni and Campylobacter coli are leading zoonotic foodborne pathogens, and the drugs of choice for human campylobacteriosis are macrolides (e.g., erythromycin) and fluoroquinolones. C. jejuni and C. coli are naturally competent for transformation via naked DNA uptake, but potential differences in transformation frequency (TF) for different antimicrobial resistance (AMR) markers remain poorly understood. We determined TFs for resistance to different antibiotics using as recipient a derivative of C. jejuni NCTC 11168 (strain SN:CM) with donor DNA from multidrug-resistant C. jejuni or C. coli. TF for nalidixic acid resistance ranked significantly highest (~1.4 × 10−3), followed by resistance to streptomycin and gentamicin. Tetracycline resistance via chromosomal tet(O) was less commonly transferred (~7.6 × 10−7), while transformation to erythromycin resistance was rare (≤4.7 × 10−8). We also determined TFs with the contemporary poultry-derived strains C. jejuni FSIS 11810577 and C. coli FSIS 1710488 as recipients. TFs to nalidixic acid and streptomycin resistance remained the highest (~7 × 10−4). However, TF for gentamicin resistance was remarkably low in certain recipient–donor combinations, while average TF for erythromycin resistance was noticeably higher (~3 × 10−6) than with SN:CM. Findings from this experimental model provide insights into factors that may impact transformation-mediated transfer of AMR leading to AMR dissemination in the agricultural ecosystem.}, number={6}, journal={MICROORGANISMS}, author={Hanafy, Zahra and Osborne, Jason A. and Miller, William G. and Parker, Craig T. and Olson, Jonathan W. and Jackson, James H. and Kathariou, Sophia}, year={2022}, month={Jun} }
 @article{gardner_olson_2018, title={Interaction of Copper Toxicity and Oxidative Stress in Campylobacter jejuni}, volume={200}, ISSN={0021-9193 1098-5530}, url={http://dx.doi.org/10.1128/JB.00208-18}, DOI={10.1128/JB.00208-18}, abstractNote={
            Copper is a required micronutrient for most aerobic organisms, but it is universally toxic at elevated levels. These organisms use homeostatic mechanisms that allow for cells to acquire enough of the element to sustain metabolic requirements while ensuring that lethal levels cannot build up in the cell.
            Campylobacter jejuni
            is an important foodborne pathogen that typically makes its way into the food chain through contaminated poultry.
            C. jejuni
            has a metabolic requirement for copper and encodes a copper detoxification system. In the course of studying this system, we have learned that it is important for avian colonization. We have also gained insight into how copper exerts its toxic effects in
            C. jejuni
            by promoting oxidative stress.
          }, number={21}, journal={Journal of Bacteriology}, publisher={American Society for Microbiology}, author={Gardner, Susan P. and Olson, Jonathan W.}, editor={DiRita, Victor J.Editor}, year={2018}, month={Nov} }
 @article{dutta_altermann_crespo_olson_siletzky_kathariou_2017, title={Identification of a Campylobacter coli methyltransferase targeting adenines at GATC sites}, volume={364}, DOI={10.1093/femsle/fnw268}, abstractNote={Abstract Campylobacter coli can infect humans and colonize multiple other animals, but its host‐associated genes or adaptations are poorly understood. Adenine methylation at GATC sites, resulting in MboI resistance of genomic DNA, was earlier frequently detected among C. coli from swine but not among turkey‐derived isolates. The underlying genetic basis has remained unknown. Comparative genome sequence analyses of C. coli 6461, a swine‐derived strain with MboI‐resistant DNA, revealed two chromosomal ORFs, 0059 and 0060, encoding a putative DNA methyltransferase and a conserved hypothetical protein, respectively, which were lacking from the genome of the turkey‐derived C. coli strain 11601, which had MboI‐susceptible DNA. To determine whether ORF0059 mediated MboI resistance and hence encoded a putative N6‐adenine DNA methyltransferase, the gene was cloned immediately upstream of a chloramphenicol resistance cassette (cat) and a PCR fragment harboring ORF0059‐cat was transformed into C. coli 11601. The transformants had MboI‐resistant DNA, suggesting a direct role of this gene in methylation of adenines at GATC sites. In silico analyses suggested that the ORF0059‐ORF0060 cassette was more frequent among C. coli from swine than certain other sources (e.g. cattle, humans). Potential impacts of ORF0059‐mediated methylation on C. coli host preference and other adaptations remain to be elucidated.}, number={7}, journal={FEMS Microbiology Letters}, author={Dutta, V. and Altermann, E. and Crespo, M. D. and Olson, J. W. and Siletzky, R. M. and Kathariou, S.}, year={2017} }
 @article{crespo_altermann_olson_miller_chandrashekhar_kathariou_2016, title={Novel plasmid conferring kanamycin and tetracycline resistance in the turkey-derived Campylobacter jejuni strain 11601MD}, volume={86}, ISSN={["1095-9890"]}, DOI={10.1016/j.plasmid.2016.06.001}, abstractNote={In Campylobacter spp., resistance to the antimicrobials kanamycin and tetracycline is frequently associated with plasmid-borne genes. However, relatively few plasmids of Campylobacter jejuni have been fully characterized to date. A novel plasmid (p11601MD; 44,095 nt) harboring tet(O) was identified in C. jejuni strain 11601MD, which was isolated from the jejunum of a turkey produced conventionally in North Carolina. Analysis of the p11601MD sequence revealed the presence of a high-GC content cassette with four genes that included tet(O) and a putative aminoglycoside transferase gene (aphA-3) highly similar to kanamycin resistance determinants. Several genes putatively involved in conjugative transfer were also identified on the plasmid. These findings will contribute to a better understanding of the distribution of potentially self-mobilizing plasmids harboring antibiotic resistance determinants in Campylobacter spp. from turkeys and other sources.}, journal={PLASMID}, author={Crespo, M. D. and Altermann, E. and Olson, J. and Miller, W. G. and Chandrashekhar, K. and Kathariou, S.}, year={2016}, month={Jul}, pages={32–37} }
 @article{noar_loveless_luis navarro-herrero_olson_bruno-barcena_2015, title={Aerobic Hydrogen Production via Nitrogenase in Azotobacter vinelandii CA6}, volume={81}, ISSN={["1098-5336"]}, url={http://europepmc.org/abstract/med/25911479}, DOI={10.1128/aem.00679-15}, abstractNote={ABSTRACT}, number={13}, journal={APPLIED AND ENVIRONMENTAL MICROBIOLOGY}, author={Noar, Jesse and Loveless, Telisa and Luis Navarro-Herrero, Jose and Olson, Jonathan W. and Bruno-Barcena, Jose M.}, year={2015}, month={Jul}, pages={4507–4516} }
 @article{kassem_khatri_sanad_wolboldt_saif_olson_rajashekara_2014, title={The impairment of methylmenaquinol:fumarate reductase affects hydrogen peroxide susceptibility and accumulation in Campylobacter jejuni}, volume={3}, ISSN={["2045-8827"]}, DOI={10.1002/mbo3.158}, abstractNote={The methylmenaquinol:fumarate reductase (Mfr) of Campylobacter jejuni is a periplasmic respiratory (redox) protein that contributes to the metabolism of fumarate and displays homology to succinate dehydrogenase (Sdh). Since chemically oxidized redox‐enzymes, including fumarate reductase and Sdh, contribute to the generation of oxidative stress in Escherichia coli, we assessed the role of Mfr in C. jejuni after exposure to hydrogen peroxide (H2O2). Our results show that a Mfr mutant (∆mfrA) strain was less susceptible to H2O2 as compared to the wildtype (WT). Furthermore, the H2O2 concentration in the ∆mfrA cultures was significantly higher than that of WT after exposure to the oxidant. In the presence of H2O2, catalase (KatA) activity and katA expression were significantly lower in the ∆mfrA strain as compared to the WT. Exposure to H2O2 resulted in a significant decrease in total intracellular iron in the ∆mfrA strain as compared to WT, while the addition of iron to the growth medium mitigated H2O2 susceptibility and accumulation in the mutant. The ∆mfrA strain was significantly more persistent in RAW macrophages as compared to the WT. Scanning electron microscopy showed that infection with the ∆mfrA strain caused prolonged changes to the macrophages’ morphology, mainly resulting in spherical‐shaped cells replete with budding structures and craters. Collectively, our results suggest a role for Mfr in maintaining iron homeostasis in H2O2 stressed C. jejuni, probably via affecting the concentrations of intracellular iron.}, number={2}, journal={MICROBIOLOGYOPEN}, author={Kassem, Issmat I. and Khatri, Mahesh and Sanad, Yasser M. and Wolboldt, Melinda and Saif, Yehia M. and Olson, Jonathan W. and Rajashekara, Gireesh}, year={2014}, month={Apr}, pages={168–181} }
 @article{wang_sharma-shivappa_olson_khan_2013, title={Production of polyhydroxybutyrate (PHB) by Alcaligenes latus using sugarbeet juice}, volume={43}, ISSN={["1872-633X"]}, DOI={10.1016/j.indcrop.2012.08.011}, abstractNote={The practicality of using sugarbeet juice as medium to grow Alcaligenes latus (ATCC 29714) for production of polyhydroxybutyrate (PHB), a biodegradable plastic, was explored in this study. Dilute sugarbeet juice, sugarbeet juice with partial and complete addition of nutrients other than sugar were used as culture media. Media with partial nutrient addition was shown to be optimal for PHB production, with final dry cell weight (DCW) 10.30 ± 1.01 g/L, PHB concentration 4.01 ± 0.95 g/L, PHB content 38.66 ± 7.28%, Yp/x (g PHB produced per g dry cell weight) 0.39 ± 0.07 and a maximum PHB productivity of 0.22 ± 0.01 g/L h. The melting temperature of PHB extracted from sugarbeet juice-grown cells supplemented with partial nutrients was measured to be 151.46 °C with crystallinity of 43.12% and the corresponding crystallinity temperature of 45.42 °C. Thermal degradation of extracted PHB occurred from 255.14 to 283.69 °C with the degradation peak at 273.86 °C.}, journal={INDUSTRIAL CROPS AND PRODUCTS}, author={Wang, Bingqing and Sharma-Shivappa, Ratna R. and Olson, Jonathan W. and Khan, Saad A.}, year={2013}, month={May}, pages={802–811} }
 @article{gardner_olson_2012, title={Barriers to Horizontal Gene Transfer in Campylobacter jejuni}, volume={79}, ISBN={["978-0-12-394318-7"]}, ISSN={["0065-2164"]}, DOI={10.1016/b978-0-12-394318-7.00002-4}, abstractNote={Campylobacter jejuni is among the most frequent agent of foodborne gastroenteritis in the world, but its physiology and pathogenesis is less well understood than other bacterial enteric pathogens. This is due in part to the incompatibility of the molecular tools that have enabled advances in the characterization of other bacterial species. Most notably, the dearth of plasmid-based complementation, reporter assays, and plasmid-based unmarked mutagenesis procedures in many of the type strains has hindered research progress. The techniques themselves are not inadequate in Campylobacter species, but rather the barrier to genetic transfer of these genetic constructs from non-Campylobacter cloning stains such as Escherichia coli. Here, we review the modes of genetic transfer in C. jejuni and review the current state of research into the mechanism of each. Also reviewed are two systems (CRISPR-Cas and restriction modification) that are common to many strains of C. jejuni and are at least partly responsible for these barriers.}, journal={ADVANCES IN APPLIED MICROBIOLOGY, VOL 79}, author={Gardner, Susan P. and Olson, Jonathan W.}, year={2012}, pages={19–42} }
 @article{crespo_olson_altermann_siletzky_kathariou_2012, title={Chromosomal tet(O)-Harboring Regions in Campylobacter coli Isolates from Turkeys and Swine}, volume={78}, ISSN={["0099-2240"]}, DOI={10.1128/aem.02258-12}, abstractNote={ABSTRACT}, number={23}, journal={APPLIED AND ENVIRONMENTAL MICROBIOLOGY}, author={Crespo, M. D. and Olson, J. W. and Altermann, E. and Siletzky, R. M. and Kathariou, S.}, year={2012}, month={Dec}, pages={8488–8491} }
 @article{kassem_khatri_esseili_sanad_saif_olson_rajashekara_2012, title={Respiratory proteins contribute differentially to Campylobacter jejuni's survival and in vitro interaction with hosts' intestinal cells}, volume={12}, ISSN={["1471-2180"]}, DOI={10.1186/1471-2180-12-258}, abstractNote={Abstract}, journal={BMC MICROBIOLOGY}, author={Kassem, Issmat I. and Khatri, Mahesh and Esseili, Malak A. and Sanad, Yasser M. and Saif, Yehia M. and Olson, Jonathan W. and Rajashekara, Gireesh}, year={2012}, month={Nov} }
 @article{wang_sharma-shivappa_olson_khan_2012, title={Upstream process optimization of polyhydroxybutyrate (PHB) by Alcaligenes latus using two-stage batch and fed-batch fermentation strategies}, volume={35}, ISSN={1615-7591 1615-7605}, url={http://dx.doi.org/10.1007/S00449-012-0749-6}, DOI={10.1007/S00449-012-0749-6}, abstractNote={This research focused on optimizing the upstream process time for production of polyhydroxybutyrate (PHB) from sucrose by two-stage batch and fed-batch fermentation with Alcaligenes latus ATCC 29714. The study included selection of strain, two-stage batch fermentations with different time points for switching to nitrogen limited media (14, 16 or 18 h) and fed-batch fermentations with varied time points (similar to two stage) for introducing nitrogen limited media. The optimal strain to produce PHB using sucrose as carbon source was A. latus ATCC 29714 with maximum-specific growth rate of 0.38 ± 0.01 h(-1) and doubling time of 1.80 ± 0.05 h. Inducing nitrogen limitation at 16 h and ending second stage at 26 h gave optimal performance for PHB production, resulting in a PHB content of 46.7 ± 12.2 % (g PHB per g dry cell weight) at the end of fermentation. This was significantly higher (P ≤ 0.05) (approximately 7 %) than the corresponding fed batch run in which nitrogen limitation was initiated at 16 h.}, number={9}, journal={Bioprocess and Biosystems Engineering}, publisher={Springer Science and Business Media LLC}, author={Wang, Bingqing and Sharma-Shivappa, Ratna R. and Olson, Jonathan W. and Khan, Saad A.}, year={2012}, month={May}, pages={1591–1602} }
 @article{taveirne_sikes_olson_2009, title={Molybdenum and tungsten in Campylobacter jejuni: their physiological role and identification of separate transporters regulated by a single ModE-like protein}, volume={74}, ISSN={["1365-2958"]}, DOI={10.1111/j.1365-2958.2009.06901.x}, abstractNote={Summary}, number={3}, journal={MOLECULAR MICROBIOLOGY}, author={Taveirne, Michael E. and Sikes, Michael L. and Olson, Jonathan W.}, year={2009}, month={Nov}, pages={758–771} }
 @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}, 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{weerakoon_borden_goodson_grimes_olson_2009, title={The role of respiratory donor enzymes in Campylobacter jejuni host colonization and physiology}, volume={47}, ISSN={["0882-4010"]}, DOI={10.1016/j.micpath.2009.04.009}, abstractNote={The human pathogen Campylobacter jejuni utilizes oxidative phosphorylation to meet all of its energy demands. The genome sequence of this bacterium encodes a number of respiratory enzymes in a branched electron transport chain that predicts the utilization of a number of electron transport chain donor and acceptor molecules. Three of these electron donor enzymes: hydrogenase, formate dehydrogenase, and 2-oxoglutarate:acceptor oxidoreductase (OOR), oxidize hydrogen, formate and alpha-ketoglutarate as electron donors, respectively. Mutations were created in these donor enzymes to isolate mutants in hydrogenase (HydB::CM), formate dehydrogenase (Fdh::CM), and OOR (OorB::CM), as well as a strain with insertions in both hydrogenase and formate dehydrogenase (Hyd::Fdh). These mutants are deficient in their respective enzyme activities and do not reduce the components of the electron transport chain when provided with their respective substrates. The presence of either hydrogen or formate in the media stimulated the growth of wild type (WT) C. jejuni (but not the associated mutant strains) and at least one of these alternative substrates is required for growth of the OOR mutant strain OorB::CM. Finally, the importance of hydrogenase, formate dehydrogenase and OOR as well as the complex I of C. jejuni are elucidated by chicken colonization assays, where the double mutant Hyd::Fdh, OorB::CM and nuo mutants are severely impaired in host colonization.}, number={1}, journal={MICROBIAL PATHOGENESIS}, author={Weerakoon, Dilan R. and Borden, Nathan J. and Goodson, Carrie M. and Grimes, Jesse and Olson, Jonathan W.}, year={2009}, month={Jul}, pages={8–15} }
 @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}, 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} }
 @article{weerakoon_olson_2008, title={The Campylobacter jejuni NADH : Ubiquinone oxidoreductase (complex I) utilizes flavodoxin rather than NADH}, volume={190}, ISSN={["1098-5530"]}, DOI={10.1128/JB.01647-07}, abstractNote={ABSTRACT}, number={3}, journal={JOURNAL OF BACTERIOLOGY}, author={Weerakoon, Dilan R. and Olson, Jonathan W.}, year={2008}, month={Feb}, pages={915–925} }
 @article{brahmachary_dashti_olson_hoover_2004, title={Helicobacter pylori FlgR is an enhancer-independent activator of sigma(54)-RNA polymerase holoenzyme}, volume={186}, DOI={10.1128/JB.186.14.4535-4535.2004}, number={14}, journal={Journal of Bacteriology}, author={Brahmachary, P. and Dashti, M. G. and Olson, J. W. and Hoover, T. R.}, year={2004}, pages={4535–4542} }
 @article{wang_conover_benoit_olczak_olson_johnson_maier_2004, title={Role of a Bacterial Organic Hydroperoxide Detoxification System in Preventing Catalase Inactivation}, volume={279}, ISSN={0021-9258 1083-351X}, url={http://dx.doi.org/10.1074/jbc.M408450200}, DOI={10.1074/jbc.M408450200}, abstractNote={In the gastric pathogen Helicobacter pylori, catalase (KatA) and alkyl hydroperoxide reductase (AhpC) are two highly abundant enzymes that are crucial for oxidative stress resistance and survival of the bacterium in the host. Here we report a connection unidentified previously between the two stress resistance enzymes. We observed that the catalase in ahpC mutant cells in comparison with the parent strain is inactivated partially (approximately 50%). The decrease of catalase activity is well correlated with the perturbation of the heme environment in catalase, as detected by electron paramagnetic resonance spectroscopy. To understand the reason for this catalase inactivation, we examined the inhibitory effects of hydroperoxides on H. pylori catalase (either present in cell extracts or added to the purified enzyme) by monitoring the enzyme activity and the EPR signal of catalase. H. pylori catalase is highly resistant to its own substrate, without the loss of enzyme activity by treatment with a molar ratio of 1:3000 H2 O2. However, it inactivated is by lower concentrations of organic hydroperoxides (the substrate of AhpC). Treatment with a molar ratio of 1:400 t-butyl hydroperoxide resulted in an inactivation of catalase by approximately 50%. UV-visible absorption spectra indicated that the catalase inactivation by organic hydroperoxides is caused by the formation of a catalytically incompetent compound II species. To further support the idea that organic hydroperoxides, which accumulate in the ahpC mutant cells, are responsible for the inactivation of catalase, we compared the level of lipid peroxidation found in ahpC mutant cells with that found in wild type cells. The results showed that the total amount of extractable lipid hydroperoxides in the ahpC mutant cells is approximately three times that in the wild type cells. Our findings reveal a novel role of the organic hydroperoxide detoxification system in preventing catalase inactivation.}, number={50}, journal={Journal of Biological Chemistry}, publisher={American Society for Biochemistry & Molecular Biology (ASBMB)}, author={Wang, Ge and Conover, Richard C. and Benoit, Stephane and Olczak, Adriana A. and Olson, Jonathan W. and Johnson, Michael K. and Maier, Robert J.}, year={2004}, month={Sep}, pages={51908–51914} }
 @article{dawson_biggie_warner_cookson_jenkins_levine_olson_1996, title={Polymerase chain reaction evidence of ehrlichia chaffeensis, an agent of human ehrlichiosis, in dogs from Southeast Virginia}, volume={57}, journal={American Journal of Veterinary Research}, author={Dawson, J. E. and Biggie, K. L. and Warner, C. K. and Cookson, K. and Jenkins, S. and Levine, J. F. and Olson, J. G.}, year={1996}, pages={1175–1179} }
 @article{wang_sharma-shivappa_olson_khan, title={Upstream process optimization of polyhydroxybutyrate (PHB) by Alcaligenes latus using two-stage batch and fed-batch fermentation strategies}, volume={35}, number={9}, journal={Bioprocess and Biosystems Engineering}, author={Wang, B. Q. and Sharma-Shivappa, R. R. and Olson, J. W. and Khan, S. A.}, pages={1591–1602} }