Ectoparasitic hematophagous dipters: potential reservoirs of dengue virus? / Dípteros ectoparásitos hematófagos: ¿reservorios potenciales del virus del dengue?

Recently, the presence of antibodies and dengue virus (DV) RNA in neotropical wild mammals, including Desmodus rotundus, was reported. In a previous study, DV was also found in a high percentage (39.6%) of ectoparasitic hematophagous dipters specifics of these hematophagous bats. In order to verify the susceptibility of these ectoparasites to DV, in this work experimental infections with VD2 of organs explants of Strebla wiedemanni and of Melophagus ovinus were performed using C6/36 cells as control. Viral titers (UFP/mL) were determined at 0, 48 and 96 hrs pi. Infected organs were observed by electron microscopy and under the confocal microscopy indirect immunofluorescence (IIF) using specific conjugates against DV. The infected organs of both species of ectoparasites replicated DV at titers similar to those obtained with the C6/36 cell line (≥106 UFP/mL). Electron microscopy and IIF showed DV replication in the digestive tract, tracheoles, reproductive organs of males but not in females, and milk glands (MG) of both species. In the fatty bodies of the MG of M. ovinus, zones with a high affinity for the DV were observed. In this work the susceptibility of S. wiedemanni and M. ovinus to DV was demonstrated and consequently the probable role of this ectoparasites as wild reservoirs of DV.

How do Plants Keep their Functional Integrity?

Unlike animals, plants possess a non-strict and sometimes very fuzzy morphology. Mutual proportions of plant parts can vary to a much greater extent than in animals, changing according to the environmental conditions and the plant needs of nutrients, water and light. Despite the existence of this fundamental difference between plants and animals, it passes almost non-reflected in most studies on plants. In this review we make a preliminary attempt to gather together the mechanisms by which plants preserve their integrity, not loosing at the same time the physiological (and morphological) flexibility which allows them adapting to the different environments they can populate.

MagIC, a genetically encoded fluorescent indicator for monitoring cellular Mg2+ using a non-Förster resonance energy transfer ratiometric imaging approach.

Intracellular Mg(2+) roles are commensurate with its abundance in the cell cytoplasm. However, little is known about Mg(2+) subcellular dynamics, primarily due to the lack of suitable Mg(2+)-selective tools to monitor this ion in intracellular compartments. To cope with this lack, we developed a Mg(2+)-sensitive indicator--MagIC (indicator for Magnesium Imaging in Cell)--composed of a functionalized yellow fluorescent protein (FP) variant fused to a red-emitting FP serving as a reference, thus allowing ratiometric imaging of Mg(2+) MagIC expressed in mammalian cells is homogeneously distributed between the cytosol and nucleus but its fusion with appropriate targeting sequences redirects it to mitochondria or the endoplasmic reticulum. MagIC shows little interference by intracellular Ca(2+) [Kd (Mg(2+)) = 5.1 mM; Kd (Ca(2+)) = 4.8 mM] and its kinetic properties (k(off) = 84 s(-1)) approach those of indicator dyes. With MagIC, as reported previously, we also observed a cytosolic Mg(2+) increase provoked by application of 50 mM MgCl2 in the medium. This effect is, however, mimicked by 75 mM KCl or 150 mM D-sorbitol addition, indicating that it is a response to the associated hyperosmotic shock and not to Mg(2+) itself. Our results confirm the functionality of MagIC as a useful tool for the long-awaited possibility of prolonged and organelle-specific monitoring of cellular Mg(2+).