- Systematic research of H2dedpa derivatives as potent inhibitors of New Delhi Metallo-β-lactamase-1
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New Delhi Metallo-β-lactamase-1 (NDM-1), a Zn (II)-dependent enzyme, can catalyze the hydrolysis of almost all β-lactam antibiotics including carbapenems, resulting in bacterial antibiotic resistance, which threatens public health globally. Based on our finding that H2dedpa is as an efficient NDM-1 inhibitor, a series of H2dedpa derivatives was systematically prepared. These compounds exhibited significant activity against NDM-1, with IC50 values 0.06–0.94 μM. In vitro, compounds 6k and 6n could restore the activity of meropenem against Klebsiella pneumoniae, Escherichia coli and Proteus mirabilis possessing either NDM or IMP. In particular, the activity of meropenem against E. coli producing NDM-4 could be improved up to 5333 times when these two compounds were used. Time–kill cell-based assays showed that 99.9% of P. mirabilis were killed when treated with meropenem in combination with compound 6k or 6n. Furthermore, compounds 6k and 6n were nonhemolytic (HC50 > 1280 μg/mL) and showed low toxicity toward mammalian (HeLa) cells. Mechanistic studies indicated that compounds 6k and 6n inhibit NDM-1 by chelating the Zn2+ ion of the enzyme.
- Bai, Meng-Meng,Cui, De-Yun,Han, Jiang-Xue,Kong, Hong-Tao,Liu, Yi-Shuang,Shen, Bo-Yuan,Wang, Cong-Cong,Xiao, Chun-Ling,Yan, Da-Chao,Yang, Yi,Zhang, En
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- PH-responsive surface activity and solubilization with novel pyrrolidone-based gemini surfactants
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A new series of pH-responsive Gemini surfactants with 2-pyrrolidone head groups, N,N′-dialkyl-N,N′-di(ethyl-2-pyrrolidone)ethylenediamine (Di-CnP, where n = 6, 8 10, 12), were synthesized and characterized by 1H NMR, 13C NMR, ESI-MS, and elemental analysis. The surface activity and micellization behavior at acidic, neutral, and basic conditions were characterized by equilibrium surface tension and fluorescence techniques. It was found that the surface activity of Di-CnP depends on the pH of aqueous solutions due to the protonation state of surfactant molecules when pH was varied. The new compounds have lower cmc and γcmc in comparison with that of m-2-m type conventional cationic Gemini surfactants and gluconamide-type nonionic Gemini surfactants. Fluorescence data confirm that micelles are formed when the concentration is above the cmc. Since micellization is of fundamental importance in surfactant applications such as solubilization, microemulsion, and related technologies, the significant difference in cmc at different pH of this new Gemini surfactant is employed to solubilize cyclohexane. The preliminary result indeed shows that the solubilization capacity of Di-CnP can be tuned by pH.
- Jiang, Zan,Li, Xuefeng,Yang, Guangfu,Cheng, Li,Cai, Bo,Yang, Yi,Dong, Jinfeng
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scheme or table
p. 7174 - 7181
(2012/07/31)
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- Method and apparatus for sunless tanning
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Apparatus for simulating skin tanning comprises a receptacle containing a fluid comprising dihydroxyacetone, a receptacle containing a fluid comprising a secondary polyamine, and dispensing means for simultaneously or sequentially providing desired amounts of dihydroxyacetone and polyamine.
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