The Mycobacterium marinum mel2 locus displays similarity to bacterial bioluminescence systems and plays a role in defense against reactive oxygen and nitrogen species.

Background: Mycobacteria have developed a number of pathways that provide partial protection against both reactive oxygen species (ROS) and reactive nitrogen species (RNS). We recently identified a locus in Mycobacterium marinum, mel2, that plays a role during infection of macrophages. The molecular mechanism of mel2 action is not well understood.

A Mycobacterium marinum mel2 mutant is defective for growth in macrophages that produce reactive oxygen and reactive nitrogen species.

Macrophages produce reactive oxygen species (ROS) and reactive nitrogen species (RNS) in response to bacterial infections. Mycobacteria are relatively resistant to ROS, but RNS inhibit growth of, and possibly even kill, mycobacteria in activated macrophages. We recently constructed a Mycobacterium marinum mel2 locus mutant, which is known to affect macrophage infection.

Entry and intracellular replication of Mycobacterium tuberculosis in cultured human microvascular endothelial cells.

Establishment of pulmonary Mycobacterium tuberculosis infection requires evasion of host innate defenses. In the lung alveoli, epithelial cells naturally resist uptake by the inhaled bacilli while macrophages patrol the epithelial surface and phagocytose foreign microbes. Alveolar microvascular endothelial cells, however, have not been examined as a potential point of direct interaction with the bacilli.

Identification of Mycobacterium marinum macrophage infection mutants.

Mycobacterium marinum is an important pathogen of humans, amphibians and fish. Most pathogenic mycobacteria, including M. marinum, infect, survive and replicate primarily intracellularly within macrophages.

Identification of Mycobacterium avium genes that affect invasion of the intestinal epithelium.

Invasion of intestinal mucosa of the host by Mycobacterium avium is a critical step in pathogenesis and likely involves several different bacterial proteins, lipids, glycoproteins, and/or glycolipids. Through the screening of an M. avium genomic library in Mycobacterium smegmatis, we have identified a number of M.