The potential pathogenic role of Mycobacterium tuberculosis H37Rv fadD33, a gene encoding an acyl-CoA synthase that is underexpressed in the attenuated strain H37Ra, was investigated. In a first approach, fadD33 was cloned and expressed in strain H37Ra to restore gene expression and fadD33-complemented bacteria were used to investigate whether fadD33 might confer any growth advantage to M. tube...

Mycobacterium tuberculosis is the causative agent of the disease, tuberculosis and H37Rv is the most studied clinical strain. We use comparative genome analysis of Mycobacterium tuberculosis H37Rv and human for the identification of potential targets dataset. We used DEG (Database of Essential Genes) to identify essential genes in the H37Rv strain. The analysis shows that 628 of the 3989 genes ...

The attenuated Mycobacterium tuberculosis H37Ra strain is an isogenic counterpart of the virulent paradigm strain H37Rv. Recently, a link between a point mutation in the PhoP transcriptional regulator and avirulence of H37Ra was established. Remarkably, a previous study demonstrated negative autoregulation of the phoP gene in H37Ra. These findings led us to study the transcriptional autoregulat...

Macrophages are the target cells for Mycobacterium tuberculosis (M. tuberculosis) as well as key effector cells for clearance of this pathogen. The aim of the present study was to measure and compare the responses of mouse peritoneal macrophages following exposure to the live M. tuberculosis H37Ra and heat-inactivated H37Rv strains. In vitro phagocytosis assays indicated that the macrophages ha...

Mcl-1 protein expression was found to be up-regulated during infection with virulent Mycobacterium tuberculosis strain H37Rv. Mcl-1 induction in THP-1 cells was optimal at a multiplicity of infection of 0.8-1.2 bacilli per macrophage and was independent of opsonin coating of the bacteria. Mcl-1 expression was elevated as early as 4 h, peaked at 5.8-fold above control cells at 24 h, and remained...

We assessed the applicability of an in vitro model of low-level infection of human monocytes to the characterization of the virulence of strains of the Mycobacterium tuberculosis family. Peripheral blood monocytes were infected at a 1:1 ratio with the virulent M. tuberculosis strain H37Rv, the avirulent M. tuberculosis strain H37Ra, and the attenuated M. bovis strain BCG. Both the percentages o...

Tuberculosis is considered a re-emerging disease and one of the most important health problems worldwide. It causes approximately three million deaths every year. In the last decades multi-drug resistant Mycobacterium tuberculosis has been detected, exacerbating the situation. The main objective of this research was to test the effect of Persea americana and Gymnosperma glutinosum (commonly use...

Novel molecular tools and genetic methods were developed to isolate genomic fragments of Mycobacterium tuberculosis that may be associated with virulence. We sought to restore virulence, a characteristic of M. tuberculosis that is correlated with growth rate in mouse spleen and lung tissue, to the avirulent strain H37Ra by complementation. A representative library of the virulent M. tuberculosi...

Background Tuberculosis (TB) caused by Mycobacterium tuberculosis (MTB) is one of the most common chronic infectious amphixenotic diseases worldwide. Prevention and control of TB are greatly difficult, due to the increase in drug-resistant TB, particularly multidrug-resistant TB. We speculated that there were some differences between drug-sensitive and drug-resistant MTB strains and that mazEF3...

The choice of host cell receptor and the mechanism of binding (opsonic versus nonopsonic) may influence the intracellular fate of Mycobacterium tuberculosis. We have identified two substrains of M. tuberculosis H37Rv, designated H37Rv-CC and -HH, that differed in their modes of binding to complement receptor type 3 (CR3) expressed in transfected Chinese hamster ovary (CHO-Mac-1) cells: H37Rv-CC...