Biology subjects

Rosa, E.

Publications and source records attributed to Rosa, E..

5 recordsLinked to original sources

bioRxiv2023

Evolution during uncorrelated environmental fluctuations: bet-hedging or phenotypic plasticity?

Evolution in fluctuating environments is predicted to disfavor specialization and instead select for alternative strategies, such as phenotypic plasticity or possibly bet-hedging, depending on the accuracy of environmental cues and type of fluctuations. While these two alternatives are often contrasted in theoretical studies, their evolution are seldom studied together in empirical work. We used experimental evolution in the nematode worm Caenorhabditis remanei to simultaneously study the evolution of plasticity and bet-hedging in environments differing only in their temperature variability. We exposed worms for 30 generations to either fluctuating or slowly increasing temperature, these two environments had the same average temperature over evolutionary time. After experimental evolution, we scored size at sexual maturity and fitness in full siblings reared in two different temperatures, optimal 20{degrees}C and mildly stressful 25{degrees}C. Experimental evolution in the fluctuating environment resulted in the evolution of increased body size plasticity but not increased bet-hedging, compared to evolution in the slowly changing environment. Plasticity followed the temperature size rule as size decreased with increasing temperature and this plastic response was adaptive. In addition, we documented substantial standing genetic variation in body size, which represents a potential for further evolutionary change.

evolutionary biology↗

bioRxiv2021

Disruption of the autism-associated gene SCN2A alters synaptic development and neuronal signaling in patient iPSC-glutamatergic neurons

SCN2A is an autism spectrum disorder (ASD) risk gene and encodes a voltage-gated sodium channel. However, the impact of autism-associated SCN2A de novo variants on human neuron development is unknown. We studied SCN2A using isogenic SCN2A-/- induced pluripotent stem cells (iPSCs), and patient-derived iPSCs harboring a p.R607* or a C-terminal p.G1744* de novo truncating variant. We used Neurogenin2 to generate excitatory glutamatergic neurons and found that SCN2A+/p.R607* and SCN2A-/- neurons displayed a reduction in synapse formation and excitatory synaptic activity using multielectrode arrays and electrophysiology. However, the p.G1744* variant, which leads to early-onset seizures in addition to ASD, altered action-potential dynamics but not synaptic activity. Proteomic and functional analysis of SCN2A+/p.R607* neurons revealed defects in neuronal morphology and bioenergetic pathways, which were not present in SCN2A+/p.G1744* neurons. Our study reveals that SCN2A de novo variants can have differential impact on human neuron function and signaling. HIGHTLIGHTS- Isogenic SCN2A-/- neurons display intrinsic hyperexcitability and impaired excitatory synapse function - SCN2A+/p.R607* variant reduces excitatory synapse function in patient neurons - C-terminal SCN2A+/p.G1744* variant enhances action potential properties but not synaptic transmission in patient neurons - SCN2A+/p.R607* variant display impacts on morphological and bioenergetic signaling networks through proteomic and functional analysis eTOC- Brown et al. examined Autism-associated SCN2A variants using patient-derived iPSC NGN2-neurons. They discover that genetic variants differentially impact neuronal development and synaptic function, and highlight neuronal and bioenergetic signaling networks underlying SCN2A loss-of-function.

neuroscience↗

bioRxiv2020

Compensatory growth in C. elegans is regulated by a thermosensitive TRP channel and increases reproductive fitness

O_LIAnimals are often not growing at the maximum rate, but can compensate for a bad start of life by subsequently increasing growth rate. While this compensatory growth is widespread, its direct fitness consequences are seldom investigated and its genetic basis is unknown. C_LIO_LIWe investigated the genetic regulation, as well as fitness and lifespan consequences of compensatory growth in response to temperature, using C. elegans knockout of the thermo-sensitive TRP ion channel TRPA-1, involved in temperature recognition. We exposed juvenile worms to cold, favourable (intermediate) or warm temperatures in order to delay or speed up development. C_LIO_LIWild-type worms initially exposed to cold temperature experienced slower growth but after being switched to a more favourable temperature, they expressed compensatory growth and caught up in size. Those initially reared at warmer temperatures than favourable experienced slower growth and attained smaller adult size after being switched to the most favourable temperature. C_LIO_LICompensatory growth also altered the reproductive schedule. While rate-sensitive individual fitness decreased by cold juvenile temperatures, as a direct effect of the substantial developmental delay, once worms returned to more favourable temperature, they shifted their reproductive schedule towards early reproduction. Therefore, when focusing on the post-treatment period, the reproductive rate increased even though lifetime reproductive success was unaffected. Surprisingly, compensatory growth did not reduce adult lifespan. In contrast to the findings for wild-type worms, juvenile temperature did not induce compensatory or slowed-down growth in the trpa-1 knockout mutants. C_LIO_LIWe thus show that the trpa-1 is involved in the network regulating temperature-induced compensatory growth in C. elegans and that this compensatory growth can influence the reproductive rate. C_LI

evolutionary biology↗

bioRxiv2019

Wood capacitance is related to water content, wood density, and anatomy across 30 temperate tree species

Water released from wood tissue during transpiration (capacitance) can meaningfully affect daily water use and drought response. To provide context for better understanding of capacitance mechanisms, we investigated links between capacitance and wood anatomy. On twig wood of 30 temperate angiosperm tree species, we measured capacitance, water content, wood density, and anatomical traits, i.e., vessel dimensions, tissue fractions, and vessel-tissue contact fractions (fraction of vessel circumference in contact with other tissues). Across all species, the strongest predictors of capacitance were wood density (WD) and predawn lumen volumetric water content (VWCL-pd, r2adj=0.44, P<0.0001). Vessel-tissue contact fractions explained an additional [~]10% of the variation in capacitance. Regression models were not improved by including predawn relative water content (RWCpd) or tissue lumen fractions. Among diffuse-porous species, VWCL-pd and vessel-ray contact fraction were the best predictors of capacitance, whereas among ring/semi-ring-porous species, VWCL-pd, WD and vessel-fibre contact fraction were the best predictors. Mean RWCpd was 0.65{+/-}0.13 and uncorrelated with WD. VWCL-pd was weakly negatively correlated with WD. Our findings imply that capacitance depends on the amount of stored water, tissue connectivity and the bulk wood properties arising from WD (e.g., elasticity), rather than the fraction of any particular tissue.

plant biology↗

bioRxiv2018

Every cloud has a silver lining: Moderate plant water stress positively impacts development, immunity, and gut microbiota of a specialist herbivore

The ongoing global temperature rise has led to increasing frequency of drought events, negatively impacting vegetation and the living organisms relying on it. Extreme drought killing host plants can clearly reduce herbivore fitness, but the impact of moderate host plant water stress on insect herbivores can vary, and may even be beneficial. The Finnish Glanville fritillary butterfly (Melitaea cinxia) has faced reduced precipitation in recent years, which has impacted population dynamics. However, whether the negative effects depend on extreme desiccation killing the host plant or moderate drought impacting plant quality remains unclear. We assessed the performance of larvae fed on moderately water-stressed Plantago lanceolata in terms of growth, gut microbial composition and immune response. We found that larvae fed on water-stressed plants had better growth, a more heterogeneous bacterial community and a shifted fungal community in the gut, and up-regulated the expression of one candidate immune gene (pelle), whereas survival remained unaffected. Most of the measured traits showed considerable variation due to family structure. Our data suggest that in temperate regions moderate host plant water stress can positively shape resource acquisition of this specialized insect herbivore, potentially by increasing nutrient accessibility or concentration. Potentially, the better larval performance may be mediated by a shift of the microbiota on water-stressed plants, calling for further research especially on the understudied gut fungal community.

ecology↗