Biology subjects

Rives, J.

Publications and source records attributed to Rives, J..

3 recordsLinked to original sources

bioRxiv2022

Sea lamprey nests promote the diversity of benthic macroinvertebrate assemblages

The habitat heterogeneity hypothesis states that increased habitat heterogeneity promotes species diversity through increased availability of ecological niches. We aimed at describing the local-scale effects of nests of the sea lamprey (Petromyzon marinus L.) as ecosystem engineer on macroinvertebrate assemblages. We hypothesized that increased streambed physical heterogeneity caused by sea lamprey spawning would modify invertebrate assemblages and specific biologic traits and promote reach-scale diversity. We sampled thirty lamprey nests of the Nive River in three zones: the unmodified riverbed (control) and zones corresponding to the nest: the area excavated (pit) and the downstream accumulation of pebbles and cobbles (mound). The increased habitat heterogeneity created by lamprey was traduced by biological heterogeneity with a reduced density of invertebrates (1160 to 6540 individuals per m2 in control, 680 to 6460 individuals per m2 in pit and 1980 to 6240 individuals per m2 in mound) and number of taxa (23.5 {+/-} 3.9 taxa for control, 18.6 {+/-} 3.9 taxa in pit and 21.2 {+/-} 4.5 taxa for mound) in the pit compared to other zones. However the overall taxa diversity in nest increased with 82 {+/-} 14 taxa compared to the 69 {+/-} 8 taxa estimated in control zone. Diversity indices were consistent with the previous results indicating a loss of diversity in pit but a higher {beta} diversity between a pit and a mound than between two control zones, especially considering Morisita index accounting for taxa abundance. Trait analysis showed high functional diversity within zones with a reduced proportion of collectors, scrapers, shredders, litter/mud preference and small invertebrates in mound, while the proportion of "slabs, blocks, stones and pebbles" preference and largest invertebrates increased. Pit presented the opposite trend, while control had globally intermediate trait proportions. Our results highlight important effects on species and functional diversity due to habitat heterogeneity created by a nest-building species, what can ultimately influence food webs and nutrient processes in river ecosystems.

ecology↗

bioRxiv2020

Tumor susceptibility gene-101 regulates glucocorticoid receptor through disorder-mediated allostery

Tumor Susceptibility Gene-101 (TSG101) is involved in endosomal maturation and has been implicated in the transcriptional regulation of several steroid hormone receptors (SHRs), although a detailed characterization of such regulation has yet to be conducted. Here we directly measure binding of TSG101 to one SHR, glucocorticoid receptor (GR). Using biophysical and cellular assays, we show that the coiled-coil domain of TSG101; 1) binds and folds the disordered N-terminal domain (NTD) of GR, 2) upon binding, improves DNA-binding of GR in vitro, and 3) enhances the transcriptional activity of GR in vivo. Our findings suggest that TSG101 is a bona fide transcriptional co-regulator of GR.

biophysics↗

bioRxiv2018

The dynamics of spawning acts by a semelparous fish and its associated energetic expenses

AO_SCPLOWBSTRACTC_SCPLOWO_LIDuring the reproductive season, animals have to manage both their energetic budget and gamete stock. In particular, for semelparous capital breeders with determinate fecundity and no parental care other than gametic investment, the depletion of energetic stock must match the depletion of gametic stock, so that individuals get exhausted just after their last egg is laid and fertilized. Although these budgets are managed continuously, monitoring the dynamics of mating acts and energy expenditure at a fine temporal scale in the wild is challenging. C_LIO_LIThis study aimed to quantify the individual dynamics of spawning acts and the concomitant energy expenditure of female Allis shad (Alosa alosa) throughout their mating season. C_LIO_LIUsing eight individual-borne accelerometers for one month, we collected tri-axial acceleration, temperature, and pressure data that we analysed to i) detect the timing of spawning acts, ii) estimate energy expenditure from tail beat frequency and water temperature, and iii) monitor changes in body roundness from the position of the dorsally-mounted tag relative to the vertical plane. C_LIO_LIFemale shad had a higher probability to spawn during warmer nights, and their spawning acts were synchronized (both individually and inter-individually) within each active night. They experienced warmer temperature, remained deeper, swan more slowly and spent less energy during daytime than night time. Over one month of spawning, they performed on average 15.75 spawning acts, spent on average 6 277 kJ and died with a significant portion of residual oocytes. The acceleration-based indicator of body roundness was correlated to condition coefficient measured at capture, and globally decreased through the spawning season, although the indicator was noisy and was not correlated to changes in estimated energy expenditure. C_LIO_LIDespite significant individual variability, our results indicate that female shad exhausted their energetic stock faster than their egg stock. Water warming will increase the rate of energy expenditure, which might increase the risk that shad die with a large stock of unspent eggs. Although perfectible, the three complementary analyses of acceleration data are promising for in situ monitoring of energy expenditure related to specific behaviour. C_LI

ecology↗