The endemic gastropod fauna of Lake Titicaca: correlation between molecular evolution and hydrographic history.

Lake Titicaca, situated in the Altiplano high plateau, is the only ancient lake in South America. This 2- to 3-My-old (where My is million years) water body has had a complex history that included at least five major hydrological phases during the Pleistocene. It is generally assumed that these physical events helped shape the evolutionary history of the lake's biota.

Preventive and therapeutic types of environmental enrichment counteract beta amyloid pathology by different molecular mechanisms.

Combined preventive and therapeutic physical/cognitive stimulation starting before disease onset and continuing over its progression reduce Alzheimer-related pathology in transgenic mice. We now report that exposure of TgCRND8 mice to an enriched environment as either a preventive or therapeutic approach is also capable to reduce Aβ burden, though with different plaque and cerebral amyloid angiopathy (CAA) morphology. Preventive treatment resulted in fewer and smaller plaques without affecting CAA, whereas in therapeutically treated mice beside reduction of CAA extent, numerous plaques of strongly diminished size were found, so that total plaque loads declined as well.