Novos sensores planejados fluorescentes derivados do núcleo 2,1,3-benzotiadiazola foram sintetizados, caracterizados e aplicados como marcadores celulares de imageamento em vivo onde se observou exclusivamente preferência por mitocôndrias em modelos celulares de câncer de mama (MCF-7). A eficiência destes novos marcadores se mostrou muito superior ao corante comercial MitoTracker® Red. Experimentos celulares e in vitro permitiram uma compreensão mais profunda da relação existente entre a arquitetura molecular planejada dos novos corantes e a seletividade celular observada

Novel designed 2,1,3-benzothiadiazole fluorescent probes were synthesized, characterized and applied as live cell fluorescence imaging probe staining only mitochondria in mammalian cancer cell lines (MCF-7). The efficiency of these new probes was found to be much superior to that of the commercially available MitoTracker® Red. Cellular and in vitro experiments allowed better understanding of the relationship between the planned molecular architecture of the new dyes and the observed cellular selectivity.

Uptake of transferrin by epimastigote forms of the protozoan Trypanosoma cruzi occurs mainly through a cytostome/ cytopharynx, via uncoated endocytic vesicles that bud off from the bottom of the cytopharynx. We have here examined whether detergent-resistant membrane (DRM) domains might be involved in this process. Purified whole cell membrane fractions were assayed for cholesterol levels and used in dot blot analyses. Detergent-resistant membrane markers (cholera B toxin and anti-flotillin-1 antibody) presented positive reaction by dot blots in cholesterol-rich/ protein-poor membrane sub-fractions. The positive dot blot fraction was submitted to lipid composition analysis, showing composition similar to that of raft fractions described for other eukaryotic cells. Immunofluorescence assays allowed the localization of punctual positive signal for flotillin-1, matching the precise cytostome/ cytopharynx location. These data were confirmed by immunofluorescence assays with the co-localization of flotillin-1 and the transferrin uptake site. Our data suggest that DRM domains occur and are integrated at the cytostome/ cytopharynx of T. cruzi epimastigotes, being the main route for transferrin uptake.

Experimental chronic (45-day-old) skin lesion in hamster hind foot induced by Leishmania (Viannia) lainsoni infection showed the presence of promastigote forms in the tissue, inside parasitophorous vacuoles, as assessed by transmission electron microscopy. Experimental in vitro interaction (24 and 48 h) between Leishmania (V.)lainsoni and J774-G8 macrophage cells also demonstrated the same profile. This morphological aspect is unusual, since in this parasite genus only amastigote forms have been described as the resistant and obligate intracellular forms.

Leishmania (Viannia) lainsoni is the Leishmania species that presents the most distinct biological (morphology, growth in axenic culture medium), biochemical (enzymatic electrophoresis profile), and molecular biology characteristics, when compared to other species of the Viannia subgenus. Development of promastigote forms of this parasite attached to the wall of the pyloric and hind gut regions of sand fly vectors is a solid characteristic that allows its positioning in the Viannia subgenus. However, taxonomic data from biochemical and molecular techniques on this Leishmania species are still not conclusive. It is evident the difficulty in taxonomically positioning this borderline Leishmania species. In this review we present the data accumulated since L. (Viannia) lainsoni has been described and we discuss its position in the Viannia subgenus.