Project description:The genomic DNAs of strains JPCM5 and 263 of L. infantum, strains LV39 and Friedlin of L. major and strains Parrot-TarII and S125 of L. tarentolae were used in comparative genomic hybridizations to reveal the intra-species and inter-species gene content, and to validate L. tarentolae Parrot-TarII genome sequencing results. Leishmania (Sauroleishmania) tarentolae was first isolated in the lizard Tarentola mauritanica. This species is not known to be pathogenic to humans but is often used as a model organism for molecular analyses or protein overproduction. The Leishmania tarentolae Parrot-TarII strain genome sequence was resolved by high-throughput sequencing technologies. The L. tarentolae genome was first assembled de novo and then aligned against the reference L. major Friedlin genome to facilitate contig positioning and annotation, providing a 23-fold coverage of the genome. This is the first non-pathogenic to humans kinetoplastid protozoan genome to be described, and it provides an opportunity for comparison with the completed genomes of the pathogenic Leishmania species. A high synteny was observed in de novo assembled contigs between all sequenced Leishmania species. A number of limited chromosomal regions diverged between L. tarentolae and L. infantum, while remaining syntenic with L. major. Globally, over 90% of the L. tarentolae gene content was shared with the other Leishmania species. There were 250 L. major genes absent from L. tarentolae, and interestingly these missing genes were primarily expressed in the intracellular amastigote stage of the pathogenic parasites. This implies that L. tarentolae may have impaired ability to survive as an intracellular parasite. In contrast to other Leishmania genomes, two gene families were expanded in L. tarentolae, namely the leishmanolysin (GP63) and a gene related to the promastigote surface antigen (PSA31C). Overall, L. tarentolae appears to have a gene content more adapted to the insect stage rather than the mammalian one. This may partly explain its inability to replicate within mammalian macrophages and its suspected preferred life style as promastigote in the lizards.
Project description:The genomic DNAs of strains JPCM5 and 263 of L. infantum, strains LV39 and Friedlin of L. major and strains Parrot-TarII and S125 of L. tarentolae were used in comparative genomic hybridizations to reveal the intra-species and inter-species gene content, and to validate L. tarentolae Parrot-TarII genome sequencing results. Leishmania (Sauroleishmania) tarentolae was first isolated in the lizard Tarentola mauritanica. This species is not known to be pathogenic to humans but is often used as a model organism for molecular analyses or protein overproduction. The Leishmania tarentolae Parrot-TarII strain genome sequence was resolved by high-throughput sequencing technologies. The L. tarentolae genome was first assembled de novo and then aligned against the reference L. major Friedlin genome to facilitate contig positioning and annotation, providing a 23-fold coverage of the genome. This is the first non-pathogenic to humans kinetoplastid protozoan genome to be described, and it provides an opportunity for comparison with the completed genomes of the pathogenic Leishmania species. A high synteny was observed in de novo assembled contigs between all sequenced Leishmania species. A number of limited chromosomal regions diverged between L. tarentolae and L. infantum, while remaining syntenic with L. major. Globally, over 90% of the L. tarentolae gene content was shared with the other Leishmania species. There were 250 L. major genes absent from L. tarentolae, and interestingly these missing genes were primarily expressed in the intracellular amastigote stage of the pathogenic parasites. This implies that L. tarentolae may have impaired ability to survive as an intracellular parasite. In contrast to other Leishmania genomes, two gene families were expanded in L. tarentolae, namely the leishmanolysin (GP63) and a gene related to the promastigote surface antigen (PSA31C). Overall, L. tarentolae appears to have a gene content more adapted to the insect stage rather than the mammalian one. This may partly explain its inability to replicate within mammalian macrophages and its suspected preferred life style as promastigote in the lizards. Six strains of three Leishmania species were hybridizated to 12 microarrays, each with four biological replicates (independent cultures). Supplementary file: Represents final results obtained after statistical analysis of all replicates.
Project description:Murine bone marrow derived macrophages were infected with Leishmania major or Leishmania donovania promastigotes, allowed to phagocytose latex beads or not treated. Gene expression profiles were compared to identify i) the effect of Leishmania infection; ii) the differences in effects between L. major and L. donovani; and iii) the effect of pahgocytosis of latex beads.
Project description:The kinetoplastid protozoan parasite, Leishmania donovani, is the causative agent of kala azar or visceral leishmaniasis. Kala azar is a severe form of leishmaniasis that is fatal in the majority of untreated cases. Studies on proteomic analysis of L. donovani thus far have been carried out using homology-based identification based on related Leishmania species (L. infantum, L. major and L. braziliensis) whose genomes have been sequenced. Recently, the genome of L. donovani was fully sequenced and the data became publicly available. We took advantage of the availability of its genomic sequence to carry out a more accurate proteogenomic analysis of L. donovani proteome using our previously generated dataset. This resulted in identification of 17,504 unique peptides upon database-dependent search against the annotated proteins in L. donovani. These peptides were assigned to 3999 unique proteins in L. donovani. 2296 proteins were identified in both the life stages of L. donovani, while 613 and 1090 proteins were identified only from amastigote and promastigote stages, respectively. The proteomic data was also searched against six-frame translated L. donovani genome, which led to 255 genome search-specific peptides (GSSPs) resulting in identification of 20 novel genes and correction of 40 existing gene models in L. donovani.
Project description:This study provides a comprehensive analysis of the secretome of seven different Leishmania species (six main human pathogenic species: L. donovani, L. infantum, L. braziliensis, L. major, L. amazonensis, L. tropica) and L. tarentolae, non-pathogenic to humans, produced by promastigotes cultured in serum-free conditions. The exhaustive analysis of the protein content of the secretome using mass spectrometry led to the identification of common and unique proteins, as well as useful insights on the relation between secretome content and pathogenesis. The biological relevance of the secretome is undeniable and, in the particular case of Leishmania parasites, it is a crucial player in the host-pathogen interactions which dictate the outcome of infection and disease severity. This study actively contributes to current knowledge on Leishmania biology and the generated datasets are an addition to current databases, associating the identified proteins with subcellular localization and putative extracellular functions.