Morphological Features of Trypanosomes from Squirrel Monkeys from the Brazilian Amazon

A morphometric analysis of blood trypomastigotes identified as Trypanosoma minasense, T. saimirii, and T. rangeli harbored by squirrel monkeys from the Brazilian Amazon was performed. Additionally, morphological and biological comparative analyses were conducted of T. saimirii-like and T. rangeli development forms from haemoculture and xenodiagnosis. Illustrations are given of blood trypomastigotes as well as of developing flagellates in triatomine and axenic culture. Mean values of blood trypomastigotes of T. saimirii differ statistically from those of T. rangeli in only two out of ten morphological characters measured, and ranges overlapped. The developing forms of T. saimrii-like parasites were essentially identical in both xenodiagnosis and haemoculture to those of T. rangeli. Trypanosomes confirmed as T. rangeli were transmitted to mice by the bites of the great majority of triatomines that fed on T. saimirii-like infected monkeys. We conclude that, based on morphology and on the development in triatomine bugs and haemoculture, T. saimirii should not be considered a distinct species. We therefore propose T. saimirii to be a junior synonym of T. rangel

Dielectrophoretic-activated cell sorter based on curved microelectrodes

This article presents the numerical and experimental analysis of a dielectrophoretic-activated cell sorter (DACS), which is equipped with curved microelectrodes. Curved microelectrodes offer unique advantages, since they create strong dielectrophoretic (DEP) forces over the tips and maintain it over a large portion of their structure, as predicted by simulations. The performance of the system is assessed using yeast (Saccharomyces cerevisiae) cells as model organisms. The separation of the live and dead cells is demonstrated at different medium conductivities of 0.001 and 0.14 S/m, and the sorting performance was assessed using a second array of microelectrodes patterned downstream the microchannel. Further, microscopic cell counting analysis reveals that a single pass through the system yields a separating efficiency of ~80% at low medium conductivities and ~85% at high medium conductivities.<br /