Here we present a T7-driven, tetracycline-inducible system for protein expression in human pathogen Leishmania mexicana. The gene expression in this strain is tightly regulated and dose- and time-dependent. This system can be widely used by the parasitology community to analyze effects of genes of interest on biology, physiology and virulence of parasites causing cutaneous leishmaniases.

Small-molecule oxidosqualene cyclase (OSC) inhibitors were found to be effective in assays against cloned OSC-like enzymes from human pathogens. A combinatorial library was prepared and used to identify lead compounds that inhibit the growth of Trypanosoma cruzi, Leishmania mexicana amazonensis, and Pneumocystis carinii in culture. Selectivity for the microorganisms in preference to mammalian c...

In Colombia, Leishmania mexicana has a scattered geographical distribution and no sand fly vectors have been associated with its transmission. During the present study, the anthropophilic sand fly Lutzomyia columbiana was found to be the only species collected using diverse methods, in a small focus of Le. mexicana in the municipality of Samaniego, SW Colombia. Ecological data indicate that thi...

Immune sera obtained from either BALB/c mice (susceptible) at 7 weeks, or C57BL/6 mice (resistant), at 7 weeks after infection with L. m. amazonensis, were effective in increasing internalization of homologous promastigotes into starch-induced peritoneal macrophages (from both mouse strains). Both the internalization enhancing effect and the levels of anti-leishmanial antibody (ELISA) were remo...

Scanning electron microscopy of the cystidicolid nematode Ascarophis mexicana Moravec, Salgado-Maldonado et Vivas-Rodríguez, 1995 enabled the first detailed study of its cephalic structure. In contrast to most Ascarophis species, its pseudolabia are highly reduced and sublabia are unlobed and weakly developed. Similascarophis is considered a synonym of Ascarophis, to which two its species are t...

The inclusion of novel small molecules in crystallization experiments has provided very encouraging results and this method is now emerging as a promising alternative strategy for crystallizing 'problematic' biological macromolecules. These small molecules have the ability to promote lattice formation through stabilizing intermolecular interactions in protein crystals. Here, the use of 1,3,6,8-...

Chitinases of trypanosomatid parasites have been proposed to fulfil various roles in their blood-feeding arthropod vectors but so far none have been directly tested using a molecular approach. We characterized the ability of Leishmania mexicana episomally transfected with LmexCht1 (the L. mexicana chitinase gene) to survive and grow within the permissive sand fly vector, Lutzomyia longipalpis. ...

We report our experience with the diagnosis and treatment o f 60 patients with American cutaneous leishmaniasis. They were infected in Panama (55), Brazil (4) or Colombia (I). Among 35 patients with a 3 week exposure in Panama, the mean maximum incubation period was 33 days (range 4-81 days). Diagnosis was delayed an average o f 93 days after onset o f skin lesions, due to the patient’s delay i...

Leishmania mexicana can cause both localized (LCL) and diffuse (DCL) cutaneous leishmaniasis, yet little is known about factors regulating disease severity in these patients. We analyzed if the disease was associated with single nucleotide polymorphisms (SNPs) in IL-1β (-511), CXCL8 (-251) and/or the inhibitor IL-1RA (+2018) in 58 Mexican mestizo patients with LCL, 6 with DCL and 123 control ca...

Immunologically intact BALB/c mice infected with Leishmania mexicana develop non-healing progressively growing lesions associated with a biased Th2 response while similarly infected IL-4Ra-deficient mice fail to develop lesions and develop a robust Th1 response. In order to determine the functional target(s) for IL-4/IL-13 inducing non-healing disease, the course of L. mexicana infection was mo...