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Antioxidants Condition Pleiotropic Vascular Responses To Exogenous H2o2: Role Of Modulation Of Vascular Tp Receptors And The Heme Oxygenase System, Nitin Puri, Fan Zhang, Sumit R. Monu, Komal R. Sodhi, Lars Bellner, Brian D. Lamon, Yilun Zhang, Nader G. Abraham, Alberto Nasjletti

Biochemistry and Microbiology

Aims: Hydrogen peroxide (H(2)O(2)), a nonradical oxidant, is employed to ascertain the role of redox mechanisms in regulation of vascular tone. Where both dilation and constriction have been reported, we examined the hypothesis that the ability of H(2)O(2) to effect vasoconstriction or dilation is conditioned by redox mechanisms and may be modulated by antioxidants.

Results: Exogenous H(2)O(2) (0.1-10.0 μM), dose-dependently reduced the internal diameter of rat renal interlobular and 3rd-order mesenteric arteries (p<0.05). This response was obliterated in arteries pretreated with antioxidants, including tempol, pegylated superoxide dismutase (PEG-SOD), butylated hydroxytoluene (BHT), and biliverdin (BV). However, as opposed to tempol or PEG-SOD, BHT & BV, antioxidants targeting radicals downstream of H(2)O(2), also uncovered vasodilation.

Innovations: Redox-dependent vasoconstriction to H(2)O(2) was blocked by inhibitors of cyclooxygenase (COX) (indomethacin-10 μM), thromboxane (TP) synthase (CGS13080-10 μM), and TP receptor antagonist (SQ29548-1 μM). However, H(2)O(2) …

Expression Of Mucoid Induction Factor Muce Is Dependent Upon The Alternate Sigma Factor Algu In Pseudomonas Aeruginosa, Yeshi Yin, F. Heath Damron, T. Ryan Withers, Christopher L. Prichett, Xin Wang, Michael J. Schurr, Hongwei Yu

Biochemistry and Microbiology

Background

Alginate overproduction in P. aeruginosa, also referred to as mucoidy, is a poor prognostic marker for patients with cystic fibrosis (CF). We previously reported the construction of a unique mucoid strain which overexpresses a small envelope protein MucE leading to activation of the protease AlgW. AlgW then degrades the anti-sigma factor MucA thus releasing the alternative sigma factor AlgU/T (σ²²) to initiate transcription of the alginate biosynthetic operon.

Results

In the current study, we mapped the mucE transcriptional start site, and determined that P_mucE activity was dependent on AlgU. Additionally, the presence of triclosan and …