Glutathione-mediated redox regulation in Cryptococcus neoformans impacts virulence.

The fungal pathogen Cryptococcus neoformans is well adapted to its host environment. It has several defence mechanisms to evade oxidative and nitrosative agents released by phagocytic host cells during infection. Among them, melanin production is linked to both fungal virulence and defence against harmful free radicals that facilitate host innate immunity.

The Monothiol Glutaredoxin Grx4 Regulates Iron Homeostasis and Virulence in Cryptococcus neoformans.

The acquisition of iron and the maintenance of iron homeostasis are important aspects of virulence for the pathogenic fungus In this study, we characterized the role of the monothiol glutaredoxin Grx4 in iron homeostasis and virulence in Monothiol glutaredoxins are important regulators of iron homeostasis because of their conserved roles in [2Fe-2S] cluster sensing and trafficking. We initially identified Grx4 as a binding partner of Cir1, a master regulator of iron-responsive genes and virulence factor elaboration in We confirmed that Grx4 binds Cir1 and demonstrated that iron repletion promotes the relocalization of Grx4 from the nucleus to the cytoplasm. We also found that a mutant lacking the GRX domain displayed iron-related phenotypes similar to those of a Δ mutant, including poor growth upon iron deprivation.

Chemical constituents, anti-inflammatory and antioxidant activities of bark extracts from Prunus tucumanensis Lillo.

The anti-inflammatory, antioxidant, antimicrobial and cytotoxic activities of the hexane (HE), chloroform (CE) and methanol (ME) extracts obtained from the bark of Prunus tucumanensis Lillo were investigated. Both ME and CE extracts displayed a significant in vitro anti-inflammatory activity similar to dexamethasone and to a commercial formulation (Pygeum) used for the treatment of benign prostatic hyperplasia (BPH). ME exhibited powerful antioxidant (67.

Adaptation of Cryptococcus neoformans to mammalian hosts: integrated regulation of metabolism and virulence.

The basidiomycete fungus Cryptococcus neoformans infects humans via inhalation of desiccated yeast cells or spores from the environment. In the absence of effective immune containment, the initial pulmonary infection often spreads to the central nervous system to result in meningoencephalitis. The fungus must therefore make the transition from the environment to different mammalian niches that include the intracellular locale of phagocytic cells and extracellular sites in the lung, bloodstream, and central nervous system.

Antibacterial and cytotoxic activities of the sesquiterpene lactones cnicin and onopordopicrin.

The antimicrobial and cytotoxic activities of chloroform extracts from the weeds Centaurea tweediei and C. diffusa, and the main sesquiterpene lactones isolated from these species, onopordopicrin and cnicin, respectively, were assayed. Results show that the chloroform extracts from both Centaurea species possess antibacterial activities against a panel of Gram-positive and Gram-negative bacteria.

Expanding fungal pathogenesis: Cryptococcus breaks out of the opportunistic box.

Cryptococcus neoformans is generally considered to be an opportunistic fungal pathogen because of its tendency to infect immunocompromised individuals, particularly those infected with HIV. However, this view has been challenged by the recent discovery of specialized interactions between the fungus and its mammalian hosts, and by the emergence of the related species Cryptococcus gattii as a primary pathogen of immunocompetent populations. In this Review, we highlight features of cryptococcal pathogens that reveal their adaptation to the mammalian environment.

MmpS4 promotes glycopeptidolipids biosynthesis and export in Mycobacterium smegmatis.

The MmpS family (mycobacterial membrane protein small) includes over 100 small membrane proteins specific to the genus Mycobacterium that have not yet been studied experimentally. The genes encoding MmpS proteins are often associated with mmpL genes, which are homologous to the RND (resistance nodulation cell division) genes of Gram-negative bacteria that encode proteins functioning as multidrug efflux system. We showed by molecular genetics and biochemical analysis that MmpS4 in Mycobacterium smegmatis is required for the production and export of large amounts of cell surface glycolipids, but is dispensable for biosynthesis per se.

Immunogenicity of Mycobacterium avium subsp. paratuberculosis proteins in Crohn's disease patients.

Unlabelled: The association between Mycobacterium avium subsp. paratuberculosis (MAP) and Crohn's disease (CD) is supported by several studies reporting the detection or isolation of MAP from human tissues, but a direct association is still debatable.

Objective: To evaluate the survival of MAP in human intestinal cells and to measure the presence of antibodies against two mycobacterial proteins necessary for the survival of the bacterium in the sera of CD patients.

Glutathione disulfide and S-nitrosoglutathione detoxification by Mycobacterium tuberculosis thioredoxin system.

Mycobacterium tuberculosis resides within alveolar macrophages. These phagocytes produce reactive nitrogen and oxygen intermediates to combat the invading pathogens. The macrophage glutathione (GSH) pool reduces nitric oxide (NO) to S-nitrosoglutathione (GSNO).

Mycothiol biosynthesis is essential for ethionamide susceptibility in Mycobacterium tuberculosis.

Spontaneous mutants of Mycobacterium tuberculosis that were resistant to the anti-tuberculosis drugs ethionamide and isoniazid were isolated and found to map to mshA, a gene encoding the first enzyme involved in the biosynthesis of mycothiol, a major low-molecular-weight thiol in M. tuberculosis. Seven independent missense or frameshift mutations within mshA were identified and characterized.