Health benefits of microalgae and their microbiomes

Microalgae comprise a phylogenetically very diverse group of photosynthetic unicellular pro- and eukaryotic organisms growing in marine and other aquatic environments. While they are well explored for the generation of biofuels, their potential as a source of antimicrobial and prebiotic substances have recently received increasing interest. Within this framework, microalgae may offer solutions to the societal challenge we face, concerning the lack of antibiotics treating the growing level of antimicrobial resistant bacteria and fungi in clinical settings. While the vast majority of microalgae and their associated microbiota remain unstudied, they may be a fascinating and rewarding source for novel and more sustainable antimicrobials and alternative molecules and compounds. In this review, we present an overview of the current knowledge on health benefits of microalgae and their associated microbiota. Finally, we describe remaining issues and limitation, and suggest several promising research potentials that should be given attention.publishedVersio

Relict lineages with extreme ecology and physiology: metal hyperaccumulation on ultramafic substrates in New Caledonian Alseuosmineae (Asterales)

International audienceBackground: Relict lineages are an important component of the biodiversity, but it is unclear under what circumstances these groups persist. A potential example of such a group is the Alseuosmineae (Asterales) of Oceania. This clade contains the three small families-Alseuosmiaceae, Argophyllaceae and Phellinaceae. The clade has highest diversity in New Caledonia, where there are extensive ultramafic substrates, creating an extreme edaphic environment. Aims: Using several lines of evidence we aimed to show that Alseuosmineae qualify as a relict lineage, with specialized adaptations for ultramafic substrates. Methods: Molecular phylogenetics and dating analyses were carried out on representatives from all Alseuosmineae genera. Metal concentration in 33 out of 44 Alseuosmineae species was measured in herbarium specimens with XRF spectrometry. Results: Dating analyses indicated that Alseuosmineae began diversifying about 75-80 million years ago, and had much slower net diversification rates than other Asterales groups. One-third of the species occur on ultramafic substrates in New Caledonia. Six are categorised as nickel hyperaccumulators, and two as manganese hyperaccumulators. Conclusions: Extinction was probably paramount in the history of Alseuosmineae, especially for continental species. We postulate that their adaptation to ultramafic substrates and metal accumulation may have contributed to their survival until today

Dans la peau d’un soldat: De la Rome antique à nos jours

Qui dit guerrier pense combat. Pourtant, le soldat en campagne passe bien plus de temps à s’entraîner, à se déplacer, à assurer sa subsistance et… à attendre.Hors armes et munitions, le paquetage du soldat répond à des besoins inchangés depuis l’Antiquité : manger, se chausser, se distinguer des adversaires et s’en protéger… Depuis toujours aussi, le combattant a connu la fraternité d’armes qui le lie aux camarades, à quoi contribuent tenue, récompenses, rituels partagés. Il est fier, enfin, de se démarquer des civils dont il doit assurer la défense.C’est à ces moments ordinaires de la vie du soldat, depuis deux millénaires, qu’est consacré cet ouvrage, à ces objets modestes, imposants ou insolites, qui lui permettent d’accomplir sa mission, lui donnent son identité, racontent son expérience quotidienne, jusque, parfois, dans la souffrance et dans la mort.Avec ce catalogue aux multiples facettes, où dialoguent de nombreuses images, des notices détaillées et les essais d’éminents spécialistes, entrez dans la peau d’un soldat! (Résumé éditeur