Small non-coding RNAs derived from transfer RNAs have been identified as a broadly conserved prokaryotic and eukaryotic response to stress. Their presence coincides with changes in developmental state associated with gene expression regulation. In the epimastigote form of Trypanosoma cruzi, tRNA fragments localize to posterior cytoplasmic granules. In the infective metacyclic form of the parasite, we found tRNA-derived fragments to be abundant and evenly distributed within the cytoplasm. The fragments were not associated with polysomes, suggesting that the tRNA-derived fragments may not be directly involved in translation control in metacyclics.

O presente trabalho teve como objetivo pesquisar a ocorrência de leishmaniose visceral em cães com sinais clínicos compatíveis, procedentes de clínicas veterinárias das diferentes regiões do Estado do Paraná e em caso positivo verificar a autoctonia dos mesmos. Dos animais com suspeita clínica e epidemiológica de LV, foi coletada amostra de sangue para realização de hemograma, provas bioquímicas, sorologia, cultura do parasito, PCR e RAPD. Os cães portadores de quadro clínico, como febre, hiperqueratose, onicogrifose e emagrecimento exagerado, tiveram gânglio poplíteo e/ou medula óssea puncionados e o conteúdo inoculado em meio de cultivo NNN. A extração de DNA do parasito em sangue e cultura foi realizada pelo método fenol/clorofórmio. A amplificação de DNA do protozoário foi feita por PCR e RAPD. Dos 24 animais analisados, o parasito foi isolado em 19 cães. As técnicas moleculares permitiram identificar 14 isolados como L. (Leihmania) infantum e cinco como L. (Viannia) braziliensis. A análise epidemiológica dos casos permitiu determinar o local de transmissão e definir que todos os cães com LV diagnosticados eram casos alóctones, ou seja eram importados de regiões endêmicas. Sugere-se que a migração dos cães de regiões endêmicas para regiões indenes poderá permitir a instalação de novos focos, desde que o agente encontre ecótopo adequado e vetor específico (Lutzomyia longipalpis).

The south region is the only area in Brazil that does not present autochthonous cases of visceral leishmaniasis (VL), however, in the state of Parana, dogs and humans have been found showing a VL compatible clinical profile. In view of this problem, the present work aimed at isolating and identifying the parasite and determining the cases autochthony. All animals clinically suspect of VL were clinically evaluated, and had samples of their blood collected for hemoculture (NNN culture medium), serology, PCR and RAPD-PCR, hemogram, and biochemical assays. The dogs presenting VL clinical profile had their lymph nodes and/or bone marrow punctured and their content inoculated in NNN culture medium. The protozoan isolated was identified by PCR and PCR-RAPD. Strains of Leishmania were isolated in 19 out of the 24 studied animals. Fourteen isolates were identified as L. (Leishmania) infantum, and five were L. (Viannia) braziliensis. In the epidemiological analysis, it was possible to determine that all dogs with L. (L.) infantum being allochthonous cases. Leishmaniasis is a zoonose that has the domestic dog as reservoir, the migration ofsuch animals can disseminate the parasite to other regions, provided the agent finds an adequate ecotope and a specific vector (Lutzomyia longipalpis).