Minor temperature shifts do not affect chromosomal ploidy but cause transcriptomic changes in Leishmania braziliensis promastigotes in vitro

BACKGROUND The leishmaniases are complex neglected diseases caused by protozoan parasites of the genus Leishmania. Leishmania braziliensis is the main etiological agent of cutaneous leishmaniasis in the New World. In recent studies, genomic changes such as chromosome and gene copy number variations (CNVs), as well as transcriptomic changes have been highlighted as mechanisms used by Leishmania species to adapt to stress situations. OBJECTIVES The aim of this study was to determine the effect of short-term minor temperature shifts in the genomic and transcriptomic responses of L. braziliensis promastigotes in vitro. METHODS Growth curves, genome and transcriptome sequencing of L. braziliensis promastigotes were conducted from cultures exposed to three different temperatures (24ºC, 28ºC and 30ºC) compared with the control temperature (26ºC). FINDINGS Our results showed a decrease in L. braziliensis proliferation at 30ºC, with around 3% of the genes showing CNVs at each temperature, and transcriptomic changes in genes encoding amastin surface-like proteins, heat shock proteins and transport proteins, which may indicate a direct response to temperature stress. MAIN CONCLUSIONS This study provides evidence that L. braziliensis promastigotes exhibit a decrease in cell density, and noticeable changes in the transcriptomic profiles. However, there were not perceptible changes at chromosome CNVs and only ~3% of the genes changed their copies in each treatment.

Cloning and sequence analysis of 4 amastin genes from Leishmania parasites / 中华传染病杂志

Objective To clone amastin coding genes from different strains of Leishmania parasites. Methods Using amastin cDNA sequence as the reference, dbEST data base established by National Center Biotechnology Information (NCBI), USA, was searched by BLAST tool. A 309 bp DNA fragment of Leishmania major was found and used as the probe for the screening of a DNA library. The amastin gene of Leishmania major Abdou was cloned and sequenced. Specific primers were designed and amastin genes for Leishmania mexicana WR972, Leishmania brizeliensis and Leishmania amazonensis joseph were amplified by polymerase chain reaction. Results The amastin genes from 4 strains of Leishmania parasites were cloned and sequenced. It was found that all 4 amastin genes contained unique open reading frame of 552 bp and encoded amastin protein of 183 amino acid residues. Conclusion The amastin genes of 4 strains of Leishmania parasites were successfully cloned.