Biology subjects

Lannes, L.

Publications and source records attributed to Lannes, L..

2 recordsLinked to original sources

bioRxiv2024

Nutrient addition in grasslands worldwide reveals proportional plant diversity decline across spatial scales but little change in beta diversity

Nutrient enrichment typically causes local plant diversity declines. A common but untested expectation is that nutrient enrichment also reduces variation in nutrient conditions among localities and selects for a smaller pool of species, causing greater diversity declines at larger than local scales and thus biotic homogenization. Here we apply a framework that links changes in species richness across scales to changes in the numbers of spatially restricted and widespread species for a standardized nutrient addition experiment across 72 grasslands on six continents. Overall, we find proportionally similar species loss at local and larger scales, suggesting similar declines of spatially restricted and widespread species, and no biotic homogenization after 4 years and up to 14 years of treatment. These patterns of diversity changes are generally consistent across species groups. Thus, nutrient enrichment poses threats to plant diversity, including for widespread species that are often critical for ecosystem functions.

ecology↗

bioRxiv2022

Formation of the active Hermes transpososome is driven by asymmetric DNA binding of BED domains

The cut-and-paste Hermes DNA transposase stands out among the transposases that have been biochemically or structurally characterized so far. Many transposases function as dimers, but the Hermes transposase forms a tetramer of dimers to achieve its active form in vivo. Intriguingly, the transposition complex, or transpososome, relies on only one dimer to perform the enzymatic reactions necessary to the mobilization of its transposon. Our investigation combining biochemical and structural approaches shows that the Hermes octamer extensively interacts with its transposon left-end (LE) engaging the BED domains of three Hermes protomers belonging to three dimers. By contrast, the right-end (RE) is entirely deprived of such interaction inside the transpososome. Our work suggests that formation of the Hermes synaptic complex is sequential and relies on the considerable difference of affinity of the transposase towards its transposon ends. Thus, we propose that Hermes dimers multimerize to gather enough BED domains to find the LE among the abundant genomic DNA, facilitating the subsequent interaction with the RE, most likely solely based on recognition of its terminal inverted repeat.

biochemistry↗