American trypanosomiasis is a chronic and endemic disease which affects millions of people.Trypanosoma cruzi, its causative agent, has a life cycle that involves complex morphological and functional transitions, as well as a variety of environmental conditions. This requires a tight regulation of gene expression, which is achieved mainly by post-transcriptional regulation. In this work we conducted an RNAseq analysis of the three major life cycle stages ofT. cruzi, amastigotes, epimastigotes and trypomastigotes. This analysis allowed us to delineate specific transcriptomic profiling for each stage, and also to identify those biological processes of major relevance in each state. Stage specific expression profiling evidenced the plasticity ofT. cruzito adapt quickly to different conditions, with particular focus on membrane remodeling and metabolic shifts along the life cycle. Epimastigotes, which replicate in the gut of insect vector, showed higher expression of genes related to energy metabolism, mainly Krebs cycle, respiratory chain and oxidative phosphorylation related genes, and anabolism related genes associated to nucleotide and steroid biosynthesis; also a general down-regulation of surface glycoproteins was seen at this stage. Trypomastigotes, living extracellularly in the bloodstream of mammals, express a plethora of surface proteins and signaling genes involved in invasion and evasion of immune response. Amastigotes mostly express membrane transporters and genes involved in regulation of cell cycle, an also express a specific subset of surface glycoproteins coding genes. In addition, these results allowed us to improve the annotation of Dm28c genome, identifying new ORFs and set the stage for construction of networks of co-expression, which can give clues about coded proteins of unknown functions.

In this work, we describe the first transcriptome based on RNA-seq technology focused on studying transcriptional changes associated with biofilm growth in a member of the genus Leptospira . As many pathogenic species of this genus can survive inside the host but also persist in environmental water, mostly forming biofilms, identifying the molecular basis of this capacity can impact the understanding of how leptospires are able to fulfill a complete life cycle that alternates between adaptation to the host and adaptation to hostile external environmental conditions. We identified several genes and regulatory networks that can be the kickoff for deepening understanding of the molecular mechanisms involving bacterial persistence via biofilm formation; understanding this is important for the future development of tools for controlling leptospirosis.

Bovine tuberculosis (bTB) poses serious risks to animal welfare and economy, as well as to public health as a zoonosis. Its etiological agent, Mycobacterium bovis, belongs to the Mycobacterium tuberculosis complex (MTBC), a group of genetically monomorphic organisms featured by a remarkably high overall nucleotide identity (99.9%). Indeed, this characteristic is of major concern for correct typing and determination of strain-specific traits based on sequence diversity. Due to its historical economic dependence on cattle production, Uruguay is deeply affected by the prevailing incidence of Mycobacterium bovis. With the world’s highest number of cattle per human, and its intensive cattle production, Uruguay represents a particularly suited setting to evaluate genomic variability among isolates, and the diversity traits associated to this pathogen. We compared 186 genomes from MTBC strains isolated worldwide, and found a highly structured population in M. bovis. The analysis of 23 new M. bovis genomes, belonging to strains isolated in Uruguay evidenced three groups present in the country. Despite presenting an expected highly conserved genomic structure and sequence, these strains segregate into a clustered manner within the worldwide phylogeny. Analysis of the non-pe/ppe differential areas against a reference genome defined four main sources of variability, namely: regions of difference (RD), variable genes, duplications and novel genes. RDs and variant analysis segregated the strains into clusters that are concordant with their spoligotype identities. Due to its high homoplasy rate, spoligotyping failed to reflect the true genomic diversity among worldwide representative strains, however, it remains a good indicator for closely related populations. This study introduces a comprehensive population structure analysis of worldwide M. bovis isolates. The incorporation and analysis of 23 novel Uruguayan M. bovis genomes, sheds light onto the genomic diversity of this pathogen, evidencing the existence of greater genetic variability among strains than previously contemplated.

Trypanosoma vivax is the earliest branching African trypanosome. This crucial phylogenetic position makes T. vivax a fascinating model to tackle fundamental questions concerning the origin and evolution of several features that characterize African trypanosomes, such as the Variant Surface Glycoproteins (VSGs) upon which antibody clearing and antigenic variation are based. Other features like gene content and trans-splicing patterns are worth analyzing in this species for comparative purposes.

We report an outbreak of canine visceral leishmaniasis in Uruguay. Blood specimens from 11/45 dogs tested positive for Leishmania spp. Specimens of Lutzomyia longipalpis sand flies were captured; typing revealed Leishmania infantum. Our findings document an expansion of visceral leishmaniasis to southern South America and risk for vectorborne transmission to humans.