Lucchetti, A. | Search bioRxiv

bioRxiv2020

Theoretical analysis predicts an optimal therapeutic strategy in distinct parkinsonian landscapes of the striatum

Parkinsons disease (PD) results from a loss of dopaminergic neurons. The age of disease onset, its progression and symptoms vary significantly between patients, pointing to a complex relationship between neuron loss and PD etiology. Yet, our understanding of the clinical variability remains incomplete. Here, we use biophysical modelling to characterize the dopaminergic landscape in the healthy and denervated striatum. Based on currently proposed mechanisms causing PD, we model three distinct denervation patterns, and show notable differences in the dopaminergic network as denervation progresses. We find local and global differences in the activity of two types of striatal neurons depending on the denervation pattern. Finally, we identify an optimal cellular strategy for maintaining normal dopamine signaling when neurons degenerate stochastically within our model. Our results derive a conceptual framework in which the clinical variability of PD is rooted in distinct denervation patterns and forms testable predictions for future PD research.

biophysics↗

bioRxiv2019

Bottom trawl catch comparison in the Mediterranean Sea: Flexible Turtle Excluder Device (TED) vs traditional gear

The Mediterranean Sea is a hotspot of biodiversity, but the high fishing pressure results in high bycatch rates of protected (sea turtles and cetaceans) and top predator species (sharks). The reduction of bycatch is challenging for fishery scientists, as conservation of these species has become a priority. Among the animals threatened by fishing activities, the loggerhead (Caretta caretta) represents a charismatic species considered as \"vulnerable\" at the global scale by IUCN.\n\nIn the Mediterranean Sea, trawl nets show the highest probabilities of bycatch of protected species, with high rates of mortality. A new flexible Turtle Excluder Device (TED) has been tested for the first time on a commercial scale in the Mediterranean Sea to assess its effectiveness in reducing bycatch. The results did not show any significant ( = 0.05) loss in terms of commercial weight, but a significant reduction of debris in the codend of the nets mounting the TED respect to traditional nets. The catch comparison of the main commercial species showed similar rates without any significant loss of sizes, with the only exception of anglerfishes (Lophius spp.) that showed a loss of the largest individuals by TED. In terms of bycatch, the traditional nets captured mostly rays and sharks, while no turtles were captured, at all. In this regard, the authors were informed by other vessels operating in the same areas at the time of the trials about some accidental catches of loggerhead turtles. Our results demonstrated that the flexible TED represents a practical and effective solution to reduce the bycatch of endangered species in coastal Mediterranean demersal multispecies fisheries, as demonstrated experimentally also in other areas of the world. The measures involving technical modifications of fishing gears require significant investments but are technically feasible and could guarantee the success of the conservation.

ecology↗