@article{parsons_azizoglu_elhanafi_kathariou_2021, title={Mutant Construction and Integration Vector-Mediated Genetic Complementation in Listeria monocytogenes}, volume={2220}, ISBN={["978-1-0716-0981-1"]}, ISSN={["1940-6029"]}, DOI={10.1007/978-1-0716-0982-8_14}, abstractNote={Genes that play a role in stress response mechanisms and other phenotypes of Listeria monocytogenes can be identified by construction and screening of mutant libraries. In this chapter, we describe the construction and screening of mutant libraries of L. monocytogenes using the plasmid pMC38, carrying a mariner-based transposon system (TC1/mariner) and constructed by Cao et al. (Appl Environ Microbiol 73:2758–2761, 2007). Following screening of mutant libraries, putative mutants are identified and the transposon is localized, leading to identification of the genes responsible for the phenotype of interest. To confirm the role of the transposon-harboring gene in the relevant phenotype, transposon mutants are genetically complemented with the wild-type gene using the site-specific temperature-sensitive integration vector pPL2, constructed by Lauer et al. (J Bacteriol 184:4177–4186, 2002).}, journal={LISTERIA MONOCYTOGENES, 2 EDITION}, author={Parsons, Cameron and Azizoglu, Reha and Elhanafi, Driss and Kathariou, Sophia}, year={2021}, pages={177–185} }
 @article{azizoglu_lyman_anderson_2013, title={Bovine Staphylococcus aureus: Dose response to iodine and chlorhexidine and effect of iodine challenge on antibiotic susceptibility}, volume={96}, ISSN={["0022-0302"]}, DOI={10.3168/jds.2012-5857}, abstractNote={Staphylococcus aureus is a gram-positive organism that is frequently associated with clinical or subclinical mastitis. The use of germicidal teat dips is one of the measures taken by the dairy industry to control mastitis. Iodine and chlorhexidine compounds are commonly used disinfectants in teat dips. We determined the minimum inhibitory concentrations (MIC) of iodine for 37 isolates of Staph. aureus and observed variations in MIC. Seven of these Staph. aureus isolates were selected as genotype group representatives based on their pulsed-field gel electrophoresis patterns. Dose responses against iodine and chlorhexidine were determined for the 7 genotype group representatives. The response of these isolates to iodine varied significantly, whereas all isolates were susceptible to chlorhexidine, even at concentrations as low as 0.0002%. We also evaluated whether exposure of Staph. aureus to sublethal levels of iodine influenced subsequent antibiotic susceptibility. No differences in antibiotic susceptibility of Staph. aureus were observed among cultures grown in brain heart infusion broth with and without supplemental iodine. The observed variation in iodine dose responses of Staph. aureus may have implications for the occurrence of Staph. aureus mastitis on dairy farms.}, number={2}, journal={JOURNAL OF DAIRY SCIENCE}, author={Azizoglu, Reha Onur and Lyman, Roberta and Anderson, Kevin L.}, year={2013}, month={Feb}, pages={993–999} }
 @article{faith_kim_azizoglu_kathariou_czuprynski_2012, title={Purine Biosynthesis Mutants (purA and purB) of Serotype 4b Listeria monocytogenes Are Severely Attenuated for Systemic Infection in Intragastrically Inoculated A/J Mice}, volume={9}, ISSN={["1556-7125"]}, DOI={10.1089/fpd.2011.1013}, abstractNote={In this study, we demonstrate that purA and purB transposon mutants of serotype 4b Listeria monocytogenes were severely impaired in their ability to colonize the gastrointestinal tract and cause systemic infection of the spleen, liver, and gallbladder following intragastric inoculation of A/J mice. The mutant strains were also impaired in their ability to multiply within Caco-2 human intestinal epithelial cells. Neither mutant was affected in resistance to synthetic gastric fluid (pH 4.5). These findings indicate that purine biosynthesis is critical for gastrointestinal virulence of L. monocytogenes serotype 4b in mice.}, number={5}, journal={FOODBORNE PATHOGENS AND DISEASE}, author={Faith, Nancy G. and Kim, Jae-Won and Azizoglu, Reha and Kathariou, Sophia and Czuprynski, Charles}, year={2012}, month={May}, pages={480–486} }
 @article{azizoglu_kathariou_2010, title={Impact of Growth Temperature and Agar Versus Liquid Media on Freeze-Thaw Tolerance of Yersinia enterocolitica}, volume={7}, ISSN={["1556-7125"]}, DOI={10.1089/fpd.2009.0526}, abstractNote={Yersinia enterocolitica is a foodborne pathogen well known for its ability to grow at low temperatures. Recent studies with another psychrotrophic foodborne pathogen, Listeria monocytogenes, revealed that temperature of growth had pronounced impact on survival following repeated freezing and thawing (cryotolerance). Listerial cryotolerance was significantly more pronounced when bacteria were grown at 37 degrees C than following growth at either 4 degrees C or 25 degrees C. However, it is not known whether such impact of growth temperature is a general adaptation shared with other foodborne pathogens. In this study, we investigated the impact of growth temperature (4 degrees C, 25 degrees C, and 37 degrees C) on cryotolerance of Y. enterocolitica. In strong contrast to findings previously obtained with Listeria spp., cryotolerance of Y. enterocolitica was impaired following growth in liquid media at 37 degrees C, with cell concentration dropping to undetectable levels (<10(1) colony forming unit/mL) following as few as six freeze-thaw cycles. On the other hand, when the bacteria were grown at 4 degrees C, cryotolerance was significantly higher (p < 0.05), and substantial survival was maintained even after 18 cycles (2-5 log reduction, depending on strain). Enhanced cryotolerance was also observed with cultures grown at 25 degrees C. Bacteria grown at 37 degrees C on agar were significantly more cryotolerant than following growth at 37 degrees C in liquid media (p < 0.05). The data suggest species-specific impact of growth temperature and liquid versus agar medium on cryotolerance of cold-tolerant bacteria.}, number={9}, journal={FOODBORNE PATHOGENS AND DISEASE}, author={Azizoglu, Reha Onur and Kathariou, Sophia}, year={2010}, month={Sep}, pages={1125–1128} }
 @article{azizoglu_kathariou_2010, title={Inactivation of a Cold-Induced Putative RNA Helicase Gene of Listeria monocytogenes Is Accompanied by Failure To Grow at Low Temperatures but Does Not Affect Freeze-Thaw Tolerance}, volume={73}, ISSN={["1944-9097"]}, DOI={10.4315/0362-028x-73.8.1474}, abstractNote={Freeze-thaw tolerance (cryotolerance) of Listeria monocytogenes is markedly influenced by temperature of growth of the bacteria, and may involve responses to low-temperature stresses encountered during freezing and thawing. A cold-sensitive mariner-based transposon mutant of L. monocytogenes F2365 was found to harbor a single insertion in LMOf2365_1746, encoding a putative RNA helicase, and earlier shown by other investigators to be induced during 4 degrees C growth of L. monocytogenes. The mutant had normal growth at 37 degrees C but completely failed to grow at either 4 or 10 degrees C, and had impaired growth and reduced swarming on soft agar at 25 degrees C. However, the mutation had no discernible influence on the ability of the bacteria to tolerate repeated freezing and thawing after growth at either 25 or 37 degrees C. The findings suggest that the transposon insertion in the putative helicase gene, in spite of the severely cold-sensitive phenotype that accompanies it, does not affect the ability of the bacteria to cope with cold-related stresses encountered during repeated freezing and thawing.}, number={8}, journal={JOURNAL OF FOOD PROTECTION}, author={Azizoglu, Reha O. and Kathariou, S.}, year={2010}, month={Aug}, pages={1474–1479} }
 @article{azizoglu_kathariou_2010, title={Temperature-Dependent Requirement for Catalase in Aerobic Growth of Listeria monocytogenes F2365}, volume={76}, ISSN={["1098-5336"]}, DOI={10.1128/aem.01223-10}, abstractNote={ABSTRACT}, number={21}, journal={APPLIED AND ENVIRONMENTAL MICROBIOLOGY}, author={Azizoglu, Reha Onur and Kathariou, Sophia}, year={2010}, month={Nov}, pages={6998–7003} }
 @article{azizoglu_osborne_wilson_kathariou_2009, title={Role of Growth Temperature in Freeze-Thaw Tolerance of Listeria spp.}, volume={75}, ISSN={["1098-5336"]}, DOI={10.1128/AEM.00458-09}, abstractNote={ABSTRACT}, number={16}, journal={APPLIED AND ENVIRONMENTAL MICROBIOLOGY}, author={Azizoglu, Reha O. and Osborne, J. and Wilson, S. and Kathariou, S.}, year={2009}, month={Aug}, pages={5315–5320} }
 @article{azizoglu_drake_2007, title={Impact of antibiotic stress on acid and heat tolerance and virulence factor expression of Escherichia coli O157 : H7}, volume={70}, ISSN={["1944-9097"]}, DOI={10.4315/0362-028X-70.1.194}, abstractNote={This study was conducted to determine the effect of antibiotic stress on the virulence factor expression, simulated gastric fluid (SGF; pH 1.5) survival, and heat tolerance (56 degrees C) of Escherichia coli O157:H7. The MIC for three antibiotics (trimethoprim, ampicillin, and ofloxacin) was determined for two E. coli O157:H7 strains (ATCC 43895 [raw hamburger isolate] and ATCC 43890 [fecal isolate]) by the dilution series method. Subsequently, cells were stressed at the MIC of each antibiotic for 4 h, and poststress tolerance and virulence factor production were evaluated. Heat tolerance (56 degrees C) was determined by the capillary tube method, and SGF (pH 1.5) survival was used to assess acid tolerance. Virulence factor expression (stx, hlyA, and eaeA) was evaluated by the creation of lacZ gene fusions and then use of the Miller assay (a beta-galactosidase assay). Stressed and control cells were evaluated in triplicate. The MIC for trimethoprim was 0.26 mg/liter for both strains; for ampicillin, it was 2.05 mg/liter for both strains; and for ofloxacin, it was 0.0256 and 0.045 mg/liter for each strain. Heat tolerance and SGF survival following antibiotic stress decreased when compared with control cells (P < 0.05). Exposure to ofloxacin increased stx and eaeA expression (P < 0.05). Exposure to ampicillin or trimethoprim increased eaeA expression (P < 0.05). hly expression increased following trimethoprim stress (P < 0.05). Antibiotics can increase E. coli O157:H7 virulence factor production, but they do not produce a cross-protective response to heat or decreased pH.}, number={1}, journal={JOURNAL OF FOOD PROTECTION}, author={Azizoglu, Reha Onur and Drake, Maryanne}, year={2007}, month={Jan}, pages={194–199} }