nitrophenols and Tuberculosis

Tuberculosis is a serious infectious disease caused by human pathogen bacteria Mycobacterium tuberculosis. Bacterial drug resistance is a very significant medical problem nowadays and development of novel antibiotics with different mechanisms of action is an important goal of modern medical science. Leucyl-tRNA synthetase (LeuRS) has been recently clinically validated as antimicrobial target. Here we report the discovery of small-molecule inhibitors of M. tuberculosis LeuRS. Using receptor-based virtual screening we have identified six inhibitors of M. tuberculosis LeuRS from two different chemical classes. The most active compound 4-{[4-(4-Bromo-phenyl)-thiazol-2-yl]hydrazonomethyl}-2-methoxy-6-nitro-phenol (1) inhibits LeuRS with IC50 of 6μM. A series of derivatives has been synthesized and evaluated in vitro toward M. tuberculosis LeuRS. It was revealed that the most active compound 2,6-Dibromo-4-{[4-(4-nitro-phenyl)-thiazol-2-yl]-hydrazonomethyl}-phenol inhibits LeuRS with IC50 of 2.27μM. All active compounds were tested for antimicrobial effect against M. tuberculosis H37Rv. The compound 1 seems to have the best cell permeability and inhibits growth of pathogenic bacteria with IC50=10.01μM and IC90=13.53μM.

Topics: Amino Acid Sequence; Antitubercular Agents; Enzyme Inhibitors; Humans; Leucine-tRNA Ligase; Models, Molecular; Molecular Sequence Data; Mycobacterium tuberculosis; Nitrophenols; Protein Structure, Tertiary; Sequence Alignment; Tuberculosis

As part of the development of the ligase chain reaction (LCR) into a tool which can be used by a wide variety of researchers, we have investigated several analytical detection systems for the products of this amplification reaction. While early work with this technology has used gel electrophoresis to separate the LCR probes from the ligated product, solid phase capture techniques are also applicable, particularly when one of the probes is modified with a 'hook' such as biotin, and the adjoining probe modified with a detectable label. In this study we report a comparison of eight different non-radioactive detection techniques and discuss the analytical sensitivity of each. Detection with laser scanning fluorescent gel electrophoresis remains the most sensitive, with the assay described herein capable of detecting 100 molecules of the Mycobacterium tuberculosis insertion element IS6110 in a background of 4 micrograms of unrelated DNA. This method was followed closely by solid-phase capture and chemiluminescence detection which gave a sensitivity of 1000 molecules of IS6110. Fluorescence detection was approximately 10-fold less sensitive than chemiluminescence detection, and absorbance detection was a further 10-fold less sensitive than fluorescence detection. However, absorbance detection even at this level can still be useful for systems where visual interpretation is desired.

Topics: Alkaline Phosphatase; Base Sequence; Biotin; DNA Ligases; DNA Transposable Elements; DNA, Bacterial; Electrophoresis; Fluorescent Dyes; Gene Amplification; Hymecromone; Indoles; Luminescent Measurements; Molecular Sequence Data; Mycobacterium tuberculosis; NADP; Nitroblue Tetrazolium; Nitrophenols; Organophosphorus Compounds; Tuberculosis

Topics: Bilirubin; Enzyme Induction; Glucuronates; Humans; Isoniazid; Liver; Liver Function Tests; Microscopy, Electron; Nitrophenols; Rifampin; Streptomycin; Transferases; Tuberculosis

Topics: Acid Phosphatase; Animals; Glucose-6-Phosphatase; Liver; Mice; Mononuclear Phagocyte System; Nitrophenols; Physiology; Research; Spleen; Tuberculosis