DNA base composition differences between species of Leishmania.
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Animals↗
Biomedical subjects
M L Chance
Publications and source records attributed to M L Chance.
Antigenic analysis of Leishmania isolates from Tachira state, Venezuela.
Studies of cutaneous leishmaniasis in 3 endemic foci in Tachira state, western Venezuela have revealed sympatric populations of parasites causing both cutaneous and mucocutaneous disease. Immunological techniques and measurement of protease/acid phosphatase activities have been used to detect species-specific parasite antigens from 3 isolates from Tachira. Identified antigens of particular interest had molecular masses of 100, 82, 66, 50 and 27 kDa, but there was a high degree of heterogeneity between the antigens of the Tachira isolates and other Venezuelan strains of Leishmania braziliensis and L. mexicana. This heterogeneity has implications concerning the selection of antigens for use in serodiagnosis of leishmaniasis.
Acid Phosphatase↗
A PEG-ELISA for the detection of Leishmania donovani antigen in circulating immune complexes.
Leishmanial antigen in circulating immune complexes (CIC) from sera of cotton-rats experimentally infected with Leishmania donovani and visceral leishmaniasis patients (VLP) was detected using a polyethylene glycol (PEG) enzyme-linked immunosorbent assay (PEG-ELISA). The immune complexes were precipitated in the cold with 12% PEG (average M(r) 6000) and then dissociated with glycine-HCl buffer. The dissociated antigen bound to the plate was then detected by peroxidase-labelled rabbit antibody raised to either amastigotes or to CIC. Serum samples from either controls or patients infected with heterologous organisms were used to define the sensitivity and specificity of the test. Leishmanial antigen was detected in the CIC from all experimentally infected animals (100% sensitivity) and in 22 of 25 of the CIC from VLP (88% sensitivity), using either conjugate. Immunoblotting of PEG-precipitated CIC from infected animals with both rabbit antisera revealed multiple antigen components. Antigens of 40, 42 and 45 kDa appeared to be specifically recognized by both antibodies; the components of 40 and 42 kDa were common to amastigote extracts and CIC from infected animals.
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The Leishmania hertigi (Kinetoplastida; Trypanosomatidae) complex and the lizard Leishmania: their classification and evidence for a neotropical origin of the Leishmania-Endotrypanum clade.
The relationships of the Leishmania hertigi complex and the lizard Leishmania species to the main groups of mammalian Leishmania and Endotrypanum parasites were examined. Restriction fragment length polymorphisms and sequences of small subunit ribosomal RNA genes and hybridization studies of kinetoplast DNA indicated that the L. hertigi complex was more closely related to the genus Endotrypanum than to the genus Leishmania. The lizard Leishmania species were found to be at the crown of the Leishmania tree. The data provides strong evidence for a Neotropical origin of the Endotrypanum/Leishmania clade since the parasites closest to the root of the tree are all found exclusively in the Neotropics. The evolution of the Leishmania/Endotrypanum clade in relation to the evolution of the known hosts of these parasites is discussed.
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Evidence for a neotropical origin of Leishmania.
Contradictory biogeographic hypotheses for either a Neotropical or a Palaearctic origin of the genus Leishmania have been proposed. Hypotheses constructed on the basis of biogeographic data must be tested against an independent dataset and cannot be supported by biogeographic data alone. In the absence of a fossil record for the Leishmania these two hypotheses were tested against a combined dataset of sequences from the DNA polymerase A catalytic subunit and the RNA polymerase II largest subunit. The phylogeny obtained provided considerable support for a Neotropical origin of the genus Leishmania and leads us to reject the hypothesis for a Palaearctic origin.
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[Ecology of a reservoir of cutaneous leishmaniasis in the region of Thiès (Senegal, West Africa). 6. Characterization and types of isolated Leishmania strains].
The authors studied the characterisation and typing of Leishmania strains isolated in the Keur-Moussa focus from human lesions (4 strains), from the digestive tract of Phlebotomus duboscqi (I strain) and from the rodents Mastomys erythroleucus (2 strains) and Tatera gambiana (2 strains). They used the following criteria: amastigote measurements, kinetoplast ultrastructure, pathogenicity in mice and hamsters, isoenzymes, kinetoplast and nuclear DNA buoyant densities and the Adler test. The results demonstrated that all the strains isolated from the various hosts and the Central Asian Leishmania major strains tested were identical according to these criteria. In addition the four human strains isolated in other regions of Senegal were also identical to those of the Keur-Moussa focus.
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