The Autophagy-Related Organelle Autophagoproteasome Is Suppressed within Ischemic Penumbra

The peri-infarct region, which surrounds the irreversible ischemic stroke area is named ischemic penumbra. This term emphasizes the borderline conditions for neurons placed within such a critical region. Area penumbra separates the ischemic core, where frank cell loss occurs, from the surrounding healthy brain tissue. Within such a brain region, nervous matter, and mostly neurons are impaired concerning metabolic conditions. The classic biochemical marker, which reliably marks area penumbra is the over-expression of the heat shock protein 70 (HSP70). However, other proteins related to cell clearing pathways are modified within area penumbra. Among these, autophagy proteins like LC3 increase in a way, which recapitulates Hsp70. In contrast, components, such as P20S, markedly decrease. Despite apparent discrepancies, the present study indicates remarkable overlapping between LC3 and P20S redistribution within area penumbra. In fact, the amount of both proteins is markedly reduced within vacuoles. Specifically, a massive loss of LC3 + P20S immuno-positive vacuoles (autophagoproteasomes) is reported here. This represents the most relevant sub-cellular alteration here described in cell clearing pathways within area penumbra. The functional significance of these findings remains to be determined and it will take a novel experimental stream to decipher the fine-tuning of such a phenomenon.

How do we construct and operate experimental streams? An overview of facilities, protocols, and studied questions

Experimental streams are bounded and partly enclosed lotic units that facilitate the simulation of certain aspects of natural stream ecosystems under controlled conditions. We summarized the current knowledge regarding experimental streams in order to support researchers in designing and undertaking future studies using experimental streams. We observed an increase in the number of such studies since 1975. The geographically uneven distribution of studies suggests that the generalization of findings to global scale may not be straightforward. Our results indicate that macroinvertebrates, fish, and algae are the most frequently studied organisms and that the size of the experimental streams was related to the focal organism group(s) studied. The size of the units decreased over time, while the number of treatments, interpreted as the combination of the levels of factors, increased. These results suggest that biologically complex studies have gradually been replaced by biologically less complex ones. In contrast, the experimental complexity (the number of treatments) and the statistical power (number of replication) increased. Finally, we identified a number of important, but poorly documented pieces of information regarding experimental stream systems and experimental protocols and made recommendations for future research.