Biology subjects

Fort, J.

Publications and source records attributed to Fort, J..

4 recordsLinked to original sources

bioRxiv2024

Conserved Lysine in transmembrane helix 5 is key for the inner gating of the LAT transporter BasC

L-amino acid transporters (LATs) play a key role in a wide range of physiological processes. Defects in LATs can lead to neurological disorders and aminoacidurias, while the overexpression of these transporters is related to cancer. BasC is a bacterial LAT transporter with an APC fold. In this study, to monitor the cytoplasmic motion of BasC, we developed a smFRET assay that can characterize the conformational states of the intracellular gate in solution at room temperature. Based on combined biochemical and biophysical data and molecular dynamics simulations, we propose a model in which the conserved lysine residue in TM5 supports TM1a to explore both open and closed states within the cytoplasmic gate under apo conditions. This equilibrium can be altered by substrates, mutation of conserved lysine 154 in TM5, or transport-blocking nanobodies. Overall, these findings provide insights into the transport mechanism of BasC and highlight the significance of the lysine residue in TM5 in the cytoplasmic gating of LATs.

biochemistry↗

bioRxiv2023

Strong breeding colony fidelity in northern gannets following High Pathogenicity Avian Influenza Virus (HPAIV) outbreak

High pathogenicity avian influenza virus (HPAIV) caused the worst seabird mass-mortalities on record in Europe across 2021-2022. The northern gannet (Morus bassanus) was one of the most affected species, with tens of thousands of casualties in the northeast Atlantic between April-September 2022. Disease outbreaks can drastically modify the movement ecology of animals and diminish spatial consistency, thereby increasing the potential for disease transmission. To detect potential changes in movement behaviour, we GPS-tracked breeding adults following the initial HPAIV outbreak, at three of the largest gannet breeding colonies where major mortality of adults and chicks occurred (Bass Rock, Scotland, UK; Grassholm, Wales, UK; Rouzic island, Brittany, France). Crucially, GPS-tracked birds remained faithful to their breeding sites and did not prospect other breeding colonies. They performed regular foraging trips at sea, similar to their behaviour before the outbreak. Gannet foraging effort was nonetheless lower than in 2019, thus surviving birds may have benefited from reduced intra- and interspecific food competition. Breeding colony fidelity of adult northern gannets following HPAIV mass-mortalities suggests limited long-term capacity to virus spread, which may contrast with the behaviour of adults during the disease outbreak, or with that of younger individuals.

ecology↗

bioRxiv2022

Body temperature rebounds on sea ice and is elevated by mercury contamination in a keystone predator

Despite overall stability, plasticity in endothermic body temperature (Tb) occurs, which may facilitate maintenance of crucial activities in the face of climate change-related environmental variations. However, this plasticity may be limited by physiological or energetic constraints, which are potentially exacerbated by other environmental stressors. For instance, chemical contamination may elevate energetic costs and have endocrine disrupting effects that undermine thermoregulation. We leveraged advanced biologging techniques to elucidate how Tb varies with different behavioral states and environmental conditions in a keystone Arctic seabird, the little auk (Alle alle). We additionally evaluated whether mercury (Hg) contamination independently affected Tb, or limited or increased state-dependent changes in Tb. Tb was highest and relatively invariable when birds were at the colony, and rebounded when birds were resting on sea ice, following declines while foraging (diving) in polar waters. These results suggest that the colony and sea ice function as thermal refuges for little auks. In addition, Tb increased with ambient temperature and relative humidity across behavioral states, and increased with wind speed when birds were flying. Little auks with higher Hg levels had higher, less variable, Tb across behaviors and environmental contexts, perhaps reflecting increased metabolic rates linked to detoxification costs. Results provide evidence for environment- and contaminant-related effects on Tb, but not interactive effects between the two, and suggest that loss of sea ice and increased environmental contamination under global change may have serious implications for Tb regulation and energy balance.

ecology↗

bioRxiv2020

Complex population structure of the Atlantic puffin revealed by whole genome analyses

The factors underlying gene flow and genomic population structure in vagile seabirds are notoriously difficult to understand due to their complex ecology with diverse dispersal barriers and extensive periods at sea. Yet, such understanding is vital for conservation management of seabirds that are globally declining at alarming rates. Here, we elucidate the population structure of the Atlantic puffin (Fratercula arctica) by assembling its reference genome and analyzing genome-wide resequencing data of 72 individuals from 12 colonies. We identify four large, genetically distinct clusters, observe isolation-by-distance between colonies within these clusters, and obtain evidence for a secondary contact zone. These observations disagree with the current taxonomy, and show that a complex set of contemporary biotic factors impede gene flow over different spatial scales. Our results highlight the power of whole genome data to reveal unexpected population structure in vagile marine seabirds and its value for seabird taxonomy, evolution and conservation.

genomics↗