Browsing Microbiology and Immunology by Author "Rocha, Edson R."
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Aerobic-Type Ribonucleotide Reductase in the Anaerobe Bacteroides fragilis
Smalley, Darren; Rocha, Edson R.; Smith, C. Jeffrey (East Carolina University, 2002-02)Bacteroides fragilis, a component of the normal intestinal flora, is an obligate anaerobe capable of long-term survival in the presence of air. Survival is attributed to an elaborate oxidative stress response that controls ... -
Biochemical and genetic analyses of a catalase from the anaerobic bacterium Bacteroides fragilis.
Rocha, Edson R.; Smith, C. Jeffrey (East Carolina University, 1995-06)A single catalase enzyme was produced by the anaerobic bacterium Bacteroides fragilis when cultures at late log phase were shifted to aerobic conditions. In anaerobic conditions, catalase activity was detected ... -
Characterization of a Peroxide-Resistant Mutant of the Anaerobic Bacterium Bacteroides fragilis
Rocha, Edson R.; Smith, C. Jeffrey (East Carolina University, 1998-11)A Bacteroides fragilis mutant resistant to hydrogen peroxide and alkyl peroxide was isolated by enrichment in increasing concentrations of hydrogen peroxide. The mutant strain was constitutively resistant to 100 mM H2O2 ... -
Characterization of Bacteroides fragilis Hemolysins and Regulation and Synergistic Interactions of HlyA and HlyB
Robertson, Kirstin P.; Smith, C. Jeffrey; Gough, Andrea M.; Rocha, Edson R. (East Carolina University, 2006-04)This study describes the presence of 10 hemolysin orthologs in the genome of the opportunistic human anaerobic pathogen Bacteroides fragilis, which is currently classified as a nonhemolytic bacterium. The hemolysins were ... -
Expression of hemolysins in vivo and role of HlyBA in an intra-abdominal infection model
Lobo, Leandro A.; Jenkins, Audrey L.; Jeffrey Smith, C.; Rocha, Edson R. (2013-04)Bacteroides fragilis is the most frequent opportunistic pathogen isolated from anaerobic infections. However, there is a paucity of information regarding the genetic and molecular aspects of gene expression of its virulence ... -
Oxidative stress response in an anaerobe, Bacteroides fragilis: a role for catalase in protection against hydrogen peroxide.
Rocha, Edson R.; Selby, Tina; Coleman, James P.; Smith, C. Jeffrey (East Carolina University, 1996-12)Survival of Bacteroides fragilis in the presence of oxygen was dependent on the ability of bacteria to synthesize new proteins, as determined by the inhibition of protein synthesis after oxygen exposure. The B. fragilis ... -
The Redox-Sensitive Transcriptional Activator OxyR Regulates the Peroxide Response Regulon in the Obligate Anaerobe Bacteroides fragilis
Rocha, Edson R.; Owens, Gary Jr; Smith, C. Jeffrey (East Carolina University, 2000-09)The peroxide response-inducible genes ahpCF, dps, and katB in the obligate anaerobe Bacteroides fragilis are controlled by the redox-sensitive transcriptional activator OxyR. This is the first functional oxidative ... -
Regulation of Bacteriodes fragilis katB mRNA by oxidative stress and carbon limitation.
Rocha, Edson R.; Smith, C. Jeffrey (East Carolina University, 1997-11)Regulation of the katB catalase gene in the anaerobic bacterium Bacteroides fragilis was studied. Northern blot hybridization analyses revealed that katB was transcribed as an approximately 1.6-kb monocistronic mRNA. The ... -
Regulation of Pseudomonas Quinolone Signal Synthesis in Pseudomonas aeruginosa
Wade, Dana S.; Calfee, M. Worth; Rocha, Edson R.; Ling, Elizabeth A.; Engstrom, Elana; Coleman, James P.; Pesci, Everett C. (East Carolina University, 2005-07)Pseudomonas aeruginosa is an opportunistic pathogen that causes chronic lung infections in cystic fibrosis patients and is a major source of nosocomial infections. This bacterium controls many virulence factors by using ... -
Thioredoxin Reductase Is Essential for Thiol/Disulfide Redox Control and Oxidative Stress Survival of the Anaerobe Bacteroides fragilis
Rocha, Edson R.; Tzianabos, Arthur O.; Smith, C. Jeffrey (East Carolina University, 2007-11)Results of this study showed that the anaerobic, opportunistic pathogen Bacteroides fragilis lacks the glutathione/glutaredoxin redox system and possesses an extensive number of putative thioredoxin (Trx) orthologs. ...