- Thiol-Containing Metallo-β-Lactamase Inhibitors Resensitize Resistant Gram-Negative Bacteria to Meropenem
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The prevalence of infections caused by metallo-β-lactamase (MBL) expressing Gram-negative bacteria has grown at an alarming rate in recent years. Despite the fact that MBLs can deactivate virtually all β-lactam antibiotics, there are as of yet no approved
- Tehrani, Kamaleddin Haj Mohammad Ebrahim,Martin, Nathaniel I.
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p. 711 - 717
(2017/10/23)
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- 4-Aryl-1,3,2-oxathiazolylium-5-olates as pH-controlled NO-donors: The next generation of S-nitrosothiols
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S-Nitrosothiols (RSNOs) are important exogenous and endogenous sources of nitric oxide (NO) in biological systems. A series of 4-aryl-1,3,2- oxathiazolylium-5-olates derivatives with varying aryl para-substituents (-CF3, -H, -Cl, and -OCH3) were synthesized. These compounds were found to release NO under acidic condition (pH = 5). The decomposition pathway of the aryloxathiazolyliumolates proceeded via an acid-catalyzed ring-opening mechanism after which NO was released and an S-centered radical was generated. Electron paramagnetic resonance (EPR) spin trapping studies were performed to detect NO and the S-centered radical using the spin traps of iron(II) N-methyl-D-glucamine dithiocarbamate [(MGD) 2-FeII] and 5,5-dimethyl-1-pyrroline N-oxide (DMPO). Also, EPR spin trapping and UV-vis spectrophotometry were used to analyze the effect of aryl para substitution on the NO-releasing property of aryloxathiazolyliumolates. The results showed that the presence of an electron-withdrawing substituent such as -CF3 enhanced the NO-releasing capability of the aryloxathiazolyliumolates, whereas an electron-donating substituent like methoxy (-OCH3) diminished it. Computational studies using density functional theory (DFT) at the PCM/B3LYP/6-31+G*7/B3LYP/6-31G* level were used to rationalize the experimental observations. The aryloxathiazolyliumolates diminished susceptibility to reduction by ascorbate or gluthathione, and their capacity to cause vasodilation as compared to other S-nitrosothiols suggests potential application in biological systems.
- Lu, Dongning,Nadas, Janos,Zhang, Guisheng,Johnson, Wesley,Zweier, Jay L.,Cardounel, Arturo J.,Villamena, Frederick A.,Wang, Peng George
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p. 5503 - 5514
(2008/02/07)
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- Chiroptical Properties of 2,2'-Dithio- and 2,2'-Diselenobisacetic Acids
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Circular dichroism (CD) studies of 2,2'-dithiobisacetic acids substituted with alkyl or phenyl groups and their diselenide analogues show that considerable interaction occurs between the disulfide (or diselenide) chromophore and the carboxyl or phenyl groups, giving rise to intense Cotton effects (CE's) which dominate the near UV region of CD spectrum.In contrast, when the disulfide and carboxyl chromophores are separated by two carbon atoms, each chromophore gives a separate CE of normal intensity at the expected wavelength with no evidence of interaction between them.
- Ringdahl, Bjoern,Craig, J. Cymerman,Fredga, Arne,Bonner, William A.
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p. 467 - 472
(2007/10/02)
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