Genetics of flower size and nectar volume in Petunia pollination syndromes

The two related Petunia species, P. axillaris and P. integrifolia, are sympatric at various locations in South America but do not hybridise. Divergent pollinator preferences are believed to be in part responsible for their reproductive isolation. The volume of nectar produced and several components of flower morphology might contribute to pollinator-dependant reproductive isolation. In this study, we aimed to identify the genetic changes underlying the quantitative differences observed between these two Petunia species in flower size and nectar volume. We mapped quantitative trait loci (QTL) responsible for the different phenotypes of P. axillaris and P. integrifolia in an inter-specific backcross population. QTL of small to moderate effect control the differences in flower size and volume of nectar. In addition, we observed strong suppression of meiotic recombination in Petunia, even between closely related species, which precluded a fine resolution of QTL mapping. Thus, our data suggest that flower size and nectar volume are highly polygenic. They are likely to have evolved gradually through pollinator-mediated adaptation or reinforcement, and are not likely to have been primary factors in early steps of pollinator isolation of P. axillaris and P. integrifoli

Genetics of flower size and nectar volume in Petunia pollination syndromes

The two related Petunia species, P. axillaris and P. integrifolia, are sympatric at various locations in South America but do not hybridise. Divergent pollinator preferences are believed to be in part responsible for their reproductive isolation. The volume of nectar produced and several components of flower morphology might contribute to pollinator-dependant reproductive isolation. In this study, we aimed to identify the genetic changes underlying the quantitative differences observed between these two Petunia species in flower size and nectar volume. We mapped quantitative trait loci (QTL) responsible for the different phenotypes of P. axillaris and P. integrifolia in an inter-specific backcross population. QTL of small to moderate effect control the differences in flower size and volume of nectar. In addition, we observed strong suppression of meiotic recombination in Petunia, even between closely related species, which precluded a fine resolution of QTL mapping. Thus, our data suggest that flower size and nectar volume are highly polygenic. They are likely to have evolved gradually through pollinator-mediated adaptation or reinforcement, and are not likely to have been primary factors in early steps of pollinator isolation of P. axillaris and P. integrifolia

Vers des ressources électroniques interconnectées : Lexica, les dictionnaires de la collection Pangloss

International audienceLa présente communication expose l’état d’avancement de réalisation de dictionnaires en ligne, étape dans l’entreprise de long terme qui consiste à tirer parti des nouvelles technologies pour relier entre elles les réalisations des linguistes dits "de terrain": grammaires, dictionnaires, et recueils de textes. Demain, dictionnaires et grammaires pourront non seulement être interconnectés, mais aussi liés aux textes qui forment le cœur des données linguistiques, ainsi qu’aux enregistrements audio et vidéo de parole spontanée. Plus que de fixer une langue au moyen de l’imprimé, il s’agit désormais de l’offrir à des modes nouveaux de navigation, en exploitant tout le potentiel de corpus en ligne, y compris par des traitements statistiques

The transcription factor Zic4 promotes tentacle formation and prevents epithelial transdifferentiation in Hydra

The molecular mechanisms that maintain cellular identities and prevent dedifferentiation or transdifferentiation remain mysterious. However, both processes are transiently used during animal regeneration. Therefore, organisms that regenerate their organs, appendages, or even their whole body offer a fruitful paradigm to investigate the regulation of cell fate stability. Here, we used Hydra as a model system and show that Zic4, whose expression is controlled by Wnt3/β-catenin signaling and the Sp5 transcription factor, plays a key role in tentacle formation and tentacle maintenance. Reducing Zic4 expression suffices to induce transdifferentiation of tentacle epithelial cells into foot epithelial cells. This switch requires the reentry of tentacle battery cells into the cell cycle without cell division and is accompanied by degeneration of nematocytes embedded in these cells. These results indicate that maintenance of cell fate by a Wnt-controlled mechanism is a key process both during homeostasis and during regeneration. </p

Prognosis and response to laser treatment of early-onset hypertrophic port-wine stains (PWS).

Background There is limited information regarding early development of soft-tissue and/or bone hypertrophy with facial port-wine stains (PWS). Objective We sought to characterize patients with hypertrophic PWS presenting during childhood. Methods Patients with a facial PWS and underlying hypertrophy that developed before the age of 18 years were included in a multicenter retrospective study. Age at onset of the hypertrophy, its location, association with odontologic problems, presence of other associated complications, and response to laser treatment were recorded. Results A total of 98 patients were included. The mean age at onset of hypertrophy, retrieved for 77 of 98 patients, was 5.6 years. The hypertrophy was congenital in 26%. Odontologic problems were noted in 39.8% of cases. Other complications, including cataract, asymmetric development of the maxillary bone, and speech delay/disorders, were reported in 18.4%. In all, 67 patients received laser treatment. Only 3% achieved complete or nearly complete clearance of the PWS. Limitations As only cases of PWS with early-onset hypertrophy were included, we were unable to calculate the prevalence of this manifestation. Conclusion PWS with early-onset hypertrophy are associated with a high rate of complications and a poor response to laser treatment. Periodic monitoring is recommended for early detection and treatment of complications

Clinical predictors of recurrences in bipolar disorders type 1 and 2: A FACE-BD longitudinal study

Objective: To examine which characteristics predict the time to a first mood recurrence at three years in Bipolar Disorder type I (BD-I) and type II (BD-II). Methods: Individuals with BD were followed up to 3 years. Turbull's extension of the Kaplan-Meier analysis for interval-censored data was used to estimate the cumulative probability of recurrence over time. Separate models were performed according to BD subtype to determine which baseline factors were predictive of recurrences and were adjusted for age, gender and educational level. Results: We included 630 individuals with BD-I and 505 with BD-II. The first recurrence of any polarity occurred earlier in BD-II (p = 0.03). The first depressive recurrence occurred earlier in BD-II (p < 0.0001), whereas the first (hypo)manic recurrence occurred earlier in BD-I (p = 0.0003). In BD-I, the clinical variables that were associated to the time to a first mood recurrence were depressive symptoms, lifetime rapid cycling, global activation and the number of psychotropic medications at baseline. In BD-II, the time to a first recurrence was associated with a younger age at onset of BD and a higher number of lifetime mood episodes. The Areas Under the Curve for both models were moderate. Conclusion: Predictors of recurrences showed few specificities to BD-I or BD-II. The ability to predict recurrences in BD based on socio-demographic and clinical variables remained too moderate for a transfer in daily practice. This study highlights the need for further studies that would include other types of predictors, such as molecular, cognitive or neuro-imaging ones, to achieve an accurate level of prediction of recurrences in BD.Sorbonne Universités à Paris pour l'Enseignement et la RechercheFondaMental-Cohorte

High-Dose Dexamethasone and Oxygen Support Strategies in Intensive Care Unit Patients With Severe COVID-19 Acute Hypoxemic Respiratory Failure

International audienc