Search

Six ionic liquids (ILs) were applied for the first time as solvents in the extraction and preconcentration of deoxyribonucleic acid (DNA) using an in situ dispersive liquid-liquid microextraction (DLLME) approach. The effect of different IL substituents and functional group on the extraction efficiency of DNA was investigated. The highest extraction efficiencies of DNA were obtained using 1-(1,2-dihydroxypropyl)-3-hexadecylimidazolium bromide (C(16)POHIM-Br) and N,N-didecyl-N-methyl-d-glucaminium bromide [(C(10))(2)NMDG-Br]. Extraction efficiencies higher than 97% were obtained using small amounts of IL (0.50mg) for each extraction. The extraction of DNA from a sample matrix containing metal ions and protein revealed that the metal ions did not interfere with the extraction of DNA and that the co-extraction of protein can be mitigated by performing the extraction under moderately acidic conditions. Data from (31)P NMR spectroscopy suggest that a combination of electrostatic and π-π interactions dominate IL-DNA complexation and that the extraction is concentration dependant., (Copyright © 2012 Elsevier B.V. All rights reserved.)

The prevalence of drug-resistant strains of Mycobacterium tuberculosis (M. tb) emphasizes the need for new antitubercular drugs. An essential component of the drug discovery process is the development of tools to rapidly screen potential drug libraries against important biological targets. Similarly to well-documented M. tb targets, the antigen 85 (Ag85) enzymes are involved in the maintenance of the mycobacterial cell wall. The products synthesized by these mycolyltransferases are the cell wall components most responsible for the reduced permeability of drugs into the bacterial cell, thereby linking Ag85 activity directly with drug resistance. This article presents the development of a high-throughput colorimetric assay suitable for direct monitoring of the enzymatic activity. The assay uses a synthetic substrate containing three chemical moieties: an octanoyl fatty acid, beta-D-glucose, and p-nitrophenyl. In the context of the assay, Ag85 catalyzes the removal of the fatty acid and releases p-nitrophenyl-beta-D-glucoside. The glucoside is hydrolyzed by beta-glucosidase to release the p-nitrophenolate chromophore. With this assay, the K(M) and k(cat) values of Ag85C were determined to be 0.047 +/- 0.008 mM and 0.062 s(-1), respectively. In addition, the assay exhibits a Z' value of 0.81 +/- 0.06, indicating its suitability for high-throughput screening applications and drug development.