Biology subjects

Jamme, F.

Publications and source records attributed to Jamme, F..

3 recordsLinked to original sources

bioRxiv2025

Aggressive trait selection influences life-history trade-offs, favoring survival over reproductive success in Drosophila melanogaster males

Life history traits are all essential traits linked to development, survival and reproduction, directly influencing individual fitness. Limited environmental or physiological resources force organisms to balance competing demands, leading to fundamental trade-offs, particularly between survival and reproduction. Male aggression is often assumed to enhance reproductive success, yet its broader association with other fitness-related traits remains unclear. To address this, we used Drosophila melanogaster Bully lines selected for high levels of male aggression, to examine relationships between aggression, chemical signaling, and essential life-history traits including reproductive behaviors and lifespan. Our results reveal that increased male aggressiveness shifts the balance of a major life-history trade-off, favoring survival over reproductive success. Bully males exhibited lower mating success, shorter mating duration and less effective chemical mate-guarding. However, this was traded-off with increased lifespan, enabling more reproductive opportunities. We also uncover potential mechanistic underpinnings of the reproductive deficits. Bully males showed differences in their cuticular hydrocarbon (CHCs) profiles and transferred lower levels of cVA to females, a mate-guarding pheromone, thereby weakening their post-mating strategy. Overall, our findings indicate that selection for male aggression is associated with a shift in a key life-history trade-off, highlighting aggression as an evolutionary force shaping adaptation of life-history traits and providing a foundation for future genetic and mechanistic studies.

animal behavior and cognition↗

bioRxiv2025

Multiple Xpa In vivo crystallization routes in HEK 293 human cells

Phase changes of macromolecules in living cells gained recently a major interest in cell biology as liquid liquid phase separation or liquid solid phase transition phenomenon being observed in increasing number of biological or pathological processes. Comprehensive characterization of these phases remains challenging and requires new methodological approaches for their complete description across spatial and temporal scales. We propose a combination of imaging methods applied to a model system and report the in vivo crystallization pathways of a macromolecule from its solution to crystalline states at the cell population level down to the meso scale. Combining various live fluorescence based techniques and a high resolution cryo imaging technique within unaltered cryopreserved cells, we could described the unexpectedly wide landscape of the in vivo crystalline states of the fluorescent coral derived protein xpa, gain information of crystal growth dynamics in cellulo, and provide hypothesis of the crystal nucleation requirements of this stochastic process.

biophysics↗

bioRxiv2020

Downregulation of the essential Rrp44 ribonuclease causes extensive ultra-structure cell modifications in Trypanosoma brucei

Rrp44/Dis3 is an essential protein conserved in all eukaryotes that functions in the maturation of many different RNA precursors and RNA surveillance. The Trypanosoma brucei Rrp44/Dis3 homologue (TbRRP44) is required for maturation of pre-rRNA, spliced leader, and U3 snoRNA precursors. Its depletion leads to inhibition of cell proliferation and eventually to cell death. In this work, we showed that TbRRP44 depletion causes a massive expansion of acidic and lysosome-derived vacuoles, enlargement of cell and nuclei sizes without changes in DNA content, mitochondrial inactivation, and autophagy induction. Consistently, 3D reconstructions using cryo-soft X-ray tomography revealed extreme vacuolation of the cytoplasm and numerous cellular alterations, including an increase in size and number of calcium-containing vesicles and lipid droplets. These multiple defects indicate that a combination of alterations converge to induce lysosome expansion. With time, the cytoplasm is taken up by lysosome-derived vacuoles, which may be a final stage leading to the cell death triggered by TbRRP44 depletion. These studies provide the first evidence on the ultra-structure cell modifications caused by deficiency of this essential ribonuclease in T. brucei.

cell biology↗