Biology subjects

BERNARD, E.

Publications and source records attributed to BERNARD, E..

3 recordsLinked to original sources

bioRxiv2024

Listening to the bats of Caraj&aacutes: Applied bioacoustics for species inventory and environment use in a mosaic of forests, savannas, and industrial mining in the Brazilian Amazonia

Bats emit echolocation calls for orientation, foraging, and social interactions. These calls are mostly species-specific, reliable for inventories and to assess habitat use, characteristics useful for large, species-rich but poorly sampled areas. This is the case of Carajas, in Brazilian Amazonia, a mosaic of cave-rich dense forests and unique metalophilous savannas (known as canga), harboring a rich bat fauna but also industrial iron ore mining, stressing the need to preserve biodiversity. We used bioacoustics (142,000 minutes of recording) to inventory bats at 61 points in Carajas and identified 43 sonotypes of seven bat families, including species rarely recorded with capture nets. Eleven species were recorded for the first time in Carajas. Species richness varied among environments - forests being the richest - but cangas had greater richness stability and a more distinct species composition. All areas with imminent mining had high bat richness. Richness in a post-mined area increased, possibly indicating resilience of some species. By providing a reference sound library for bats in Carajas, we proved the usefulness of biacoustics to improve the environmental licensing processes involving mining in biodiversity-rich areas, useful not only for Amazonia but also for other tropical environments with high bat species richness.

ecology↗

bioRxiv2024

An efficient biochemical method for characterizing and classifying potentially amyloidogenic and therapeutic peptides

Amyloidosis are proteinopathies characterized by systemic or organ-specific deposition of proteins in the form of amyloid fibers. Nearly forty proteins have been identified to play a role in these pathologies and the structures of the associated fibers are beginning to be determined by Cryo-EM. However, the molecular events underlying the process, such as fiber nucleation and elongation, are poorly understood, which impairs developing efficient therapies. In most cases, only a few dozen amino acids of the pathological protein are found in the final structure of the fibers, while amyloid peptides comprising 5 to 10 amino acids are involved in fibers nucleation process. The identification and biochemical characterization of these peptides is therefore of major scientific and clinical importance. In silico approaches are limited due to the peptides small size and long-distance intra- and intermolecular interactions that occur during nucleation. To address this problem, we developed a novel biochemical method for characterizing and classifying batches of related peptides. Initial work to optimize our approach is based on the reference peptide PHF6 ({beta}1) from Microtubule Associated Protein Tau (MAPT) as compared to 22 related peptides. We classified these peptides into groups displaying different biochemical properties, and thereby identified new amyloid peptides and peptides with therapeutic potential. We underline that our method is applicable to any family of peptides and could be scaled up for high-throughput analyses.

biochemistry↗

bioRxiv2022

Bats as ecosystem engineers in iron ore caves in the Carajas National Forest, Brazilian Amazonia

Ecosystem engineers are organisms able to modify their environment by changing the distribution of materials and energy, with effects on biotic and abiotic ecosystem components. Several ecosystem engineers are known, but for most of them the mechanisms behind their influence are poorly known. We detail the role of bats as ecosystem engineers in iron ore caves in the Carajas National Forest, Brazilian Amazonia, an area with > 1,500 caves, some holding [~]150,000 bats. We analyzed the chemical composition of guano deposits in bat caves, radiocarbon-dated those deposits, and elucidated the chemical mechanisms involved and the role the bat guano has on structuring those caves. The insect-composed guano was rich in organic matter, with high concentrations of carbon, nitrogen, phosphorus pentoxide and ferric oxide, plus potassium oxide, calcium and sulfur trioxide. Radiocarbon dating indicated guano deposits between 22,000 and 1,800 years old. The guano pH was mainly acid (from 2.1 to 5.6). Percolating waters in those bat caves were also acid (pH reaching 1.5), with the presence of phosphate, iron, calcium, nitrate and sulfate. Acid solutions due to guano decomposition and possible microbial activity produced various forms of corrosion on the cave[s] floor and walls, resulting in their enlargement. Caves with active or inactive bat colonies had, on average, horizontal projections 4.5 times larger, areas 4.4 times larger, and volumes 5.0 times bigger than the reginal average, plus more abundant, diversified and bigger speleothems. In an example of bioengineering, the long-term presence of bats (> 22,000 years) and the guano deposits they produce, mediated by biological and chemical interactions along millennia, resulted in very unique ecological, evolutionary and geomorphological processes, whose working are just beginning to be better understood by science. However, the current expansion of mineral activities coupled with the loosening of licensing and cave protection rules is a real conservation threat to the bat caves in Carajas. The destruction of those caves would represent and unacceptable loss of both speleological and biological heritage and we urge that, whenever they occur, bat caves and their colonies must be fully protected and left off-limits of mineral extraction.

ecology↗