RETRATO SIN IDENTIFICAR [Material gráfico]

Copia digital. Madrid : Ministerio de Educación, Cultura y Deporte, 201

New insight of the evolution of storage polysaccharide metabolism in the Archaeplastida lineages

Les Archaeplastides sont apparus il y a environ 1,6 milliard d'années lorsqu'une cellule eucaryote a établi une symbiose avec deux autres organismes: une cyanobactérie et une chlamydiales. Durant l'endosymbiose, la cyanobactérie a évolué vers le plaste, tandis que les chlamydiales ont laissé pour empreintes une cinquantaine de gènes chez les Archaeplastides. En parallèle les Archaeplastides ont substitué leur biosynthèse de glycogène, par celle de l'amidon. Si le rôle de la cyanobactérie est évident dans l'émergence des Archaeplastides, qu'en est-il des bactéries parasitaires? Un effecteur sécrété par les chlamydiales correspond à l'activité de la glycogène synthase (GlgA). Des analyses phylogénétiques nous signalent que les isoformes d'amidon synthases III/IV ont probablement évolué à partir d'une GlgA provenant d'une chlamydiale. Nous avons formulé l'hypothèse que l'activité GlgA des chlamydiales possède une propriété biochimique unique expliquant pourquoi elle a été sélectionnée chez les Archaeplastides. Dans ce manuscrit, nous avons premièrement rapporté la caractérisation de la mutation d'une souche de cyanobactérie, ne synthétisant plus que du glycogène. Ceci est corrélé avec une défectuosité dans GlgA2. Ces résultats suggèrent que GlgA2 est indispensable à la synthèse d'amidon chez Cyanobacterium sp. CLg1. Nous nous sommes également occupés de caractériser les activités synthases des chlamydiales. L'activité GlgA de certaines chlamydiales est capable d'utiliser les deux nucléotides sucres : ADP-glucose et UDP-glucose. Ces résultats démontrent que l'activité GlgA de certaines chlamydiales a évolué de manière à mieux détourner le stockage des carbohydrates de l'hôte.The Archaeplastida appear approximately 1.6 billion years ago when a heterotrophic eukaryote cell established a symbiotic relationship with two partners: a cyanobacterium and a chlamydiales. During the endosymbiosis process, the cyanobacterium has evolved to plastid, while chlamydiales have left in Archaeplastida a fingerprint of 50 genes. In parallel Archaeplastida have substituted the glycogen biosynthesis by starch. If the role of ancestral cyanobacteria is pretty obvious in the emergence of Archaeplastida, what about those parasitic bacteria? One effectors secreted by the chlamydiales corresponds to glycogen synthase activity (GlgA). Phylogenetic analyses point out that starch synthase III/IV isoforms have probably evolved from GlgA of chlamydiales. We hypothesize that GlgA activity of chlamydiales displays unique biochemical properties that could explain why this activity has been selected in the Archaeplastida. In this manuscript, we, first, report the characterization of mutant strain of cyanobacterium strain, which produce only glycogen. This phenotype is correlated with a defect in the GlgA2 isoform, which belongs to the same family of SSIII/IV of plants. Altogether, results suggest that GlgA2 is indispensable to starch in the Cyanobacterium sp. CLg1. We also carry out the biochemical characterization of synthase activities of the chlamydiales. We show that GlgA activities of some chlamydiales are able to use both nucleotide-sugars: ADP-glucose and UDP-glucose. These results stress out that GlgA activities of some chlamydial species have evolved to be more efficient to hijack the carbohydrate storage of infected cell

Data from: Co-adjustment of yolk antioxidants and androgens in birds

Mothers can shape the developmental trajectory of their offspring through the transmission of resources such as hormones, antioxidants or immunoglobulins. Over the last two decades, an abundant literature on maternal effects in birds has shown that several of these compounds (i.e. androgens, glucocorticoids and antioxidants) often influence the same offspring phenotypic traits (i.e. growth, immunity or oxidative stress levels), making interaction effects between egg components a likely scenario. However, the potential interactive effects of maternally transmitted compounds on offspring development and potential co-adjustment of these compounds within an egg are still poorly understood. Here, we report the results of an interspecific comparative analysis on birds' egg yolk composition (i.e. androgens and antioxidants) where we found that yolk carotenoid and vitamin E concentrations are positively associated, supporting the hypothesis that these two antioxidants act in synergy. The concentrations of vitamin E also increased with increasing concentrations of testosterone. This last result confirms the emerging idea that androgens and antioxidants are co-adjusted within eggs and that maternally transmitted antioxidants might limit the potential direct and indirect effects of prenatal exposure to high testosterone levels on oxidative stress

Results with body mass as covariable from Co-adjustment of yolk antioxidants and androgens in birds

Results with body mass as covariabl

SM Dataset Giraudeau & Ducatez BL

SM Dataset Giraudeau & Ducatez B

Interactive effects of yolk testosterone and carotenoid on prenatal growth and offspring physiology in a precocial bird

Conditions experienced by individuals during prenatal development can have long-term effects on their phenotype. Maternally transmitted resources are important mediators of such prenatal effects, but the potential interactive effects among them in shaping offspring phenotype have never been studied. Maternally derived testosterone is known to stimulate growth, but these benefits may be counterbalanced by an increase in the production of reactive oxygen species (ROS). Maternally transmitted carotenoids might have the capacity to scavenge ROS and thereby buffer an increase in oxidative stress caused by prenatal exposure to high testosterone levels. Here, we experimentally tested for such interactive effects between maternal yolk testosterone and carotenoid in Japanese quail (Coturnix japonica). We found that hatching mass was reduced and reactive oxygen metabolites (ROMs) levels at the end of the period of maximal growth increased in chicks from eggs injected with either testosterone or carotenoid (only a tendency in chicks from testosterone-injected eggs). However, when both egg compounds were manipulated simultaneously, hatching mass and ROM levels were not affected, showing that both carotenoid and testosterone lose their detrimental effects when the ratio between the 2 compounds is balanced. Our study provides the first experimental evidence for interactive effects of 2 maternally derived egg compounds on offspring phenotype and suggests that developmental cues are tightly coadjusted within an egg

Data from: Interactive effects of yolk testosterone and carotenoid on prenatal growth and offspring physiology in a precocial bird

Conditions experienced by individuals during prenatal development can have long-term effects on their phenotype. Maternally transmitted resources are important mediators of such prenatal effects, but the potential interactive effects among them in shaping offspring phenotype have never been studied. Maternally derived testosterone is known to stimulate growth, but these benefits may be counterbalanced by an increase in the production of reactive oxygen species (ROS). Maternally transmitted carotenoids might have the capacity to scavenge ROS and thereby buffer an increase in oxidative stress caused by prenatal exposure to high testosterone levels. Here, we experimentally tested for such interactive effects between maternal yolk testosterone and carotenoid in Japanese quail (Coturnix japonica). We found that hatching mass was reduced and reactive oxygen metabolites (ROMs) levels at the end of the period of maximal growth increased in chicks from eggs injected with either testosterone or carotenoid (only a tendency in chicks from testosterone-injected eggs). However, when both egg compounds were manipulated simultaneously, hatching mass and ROM levels were not affected, showing that both carotenoid and testosterone lose their detrimental effects when the ratio between the 2 compounds is balanced. Our study provides the first experimental evidence for interactive effects of 2 maternally derived egg compounds on offspring phenotype and suggests that developmental cues are tightly coadjusted within an egg