Genomic repeat abundances contain phylogenetic signal

A large proportion of genomic information, particularly repetitive elements, is usually ignored when researchers are using next-generation sequencing. Here we demonstrate the usefulness of this repetitive fraction in phylogenetic analyses, utilizing comparative graph-based clustering of next-generation sequence reads, which results in abundance estimates of different classes of genomic repeats. Phylogenetic trees are then inferred based on the genome-wide abundance of different repeat types treated as continuously varying characters; such repeats are scattered across chromosomes and in angiosperms can constitute a majority of nuclear genomic DNA. In six diverse examples, five angiosperms and one insect, this method provides generally well-supported relationships at interspecific and intergeneric levels that agree with results from more standard phylogenetic analyses of commonly used markers. We propose that this methodology may prove especially useful in groups where there is little genetic differentiation in standard phylogenetic markers. At the same time as providing data for phylogenetic inference, this method additionally yields a wealth of data for comparative studies of genome evolution

Nongenotoxic 3-Nitroimidazo[1,2-a]pyridines Are NTR1 Substrates That Display Potent in Vitro Antileishmanial Activity

Twenty nine original 3-nitroimidazo[1,2-a]pyridine derivatives, bearing a phenylthio (or benzylthio) moiety at position 8 of the scaffold, were synthesized. In vitro evaluation highlighted compound 5 as an antiparasitic hit molecule displaying low cytotoxicity for the human HepG2 cell line (CC50 > 100 mu M) alongside good antileishmanial activities (IC50 = 1-2.1 mu M) against L. donovani, L. infantum, and L. major; and good antitrypanosomal activities (IC50 = 1.3-2.2 mu M) against T. brucei brucei and T. cruzi, in comparison to several reference drugs such as miltefosine, fexinidazole, eflornithine, and benznidazole (IC50 = 0.6 to 13.3 mu M). Molecule 5, presenting a low reduction potential (E degrees = -0.63 V), was shown to be selectively bioactivated by the L. donovani type 1 nitroreductase (NTR1). Importantly, molecule 5 was neither mutagenic (negative Ames test), nor genotoxic (negative comet assay), in contrast to many other nitroaromatics. Molecule 5 showed poor microsomal stability; however, its main metabolite (sulfoxide) remained both active and nonmutagenic, making 5 a good candidate for further in vivo studies

The “Nuits des ´etoiles” events (1991–2008) and their impact on the French astronomical leisure landscape

The popular event Nuits des ´etoiles has become in France the summer encounter with the sky. More than 400 events are set up for three consecutive days each year: several thousands of voluntary organisers invite more and more people to observe the heavens and discover astronomy. Each summer, those collective star parties reach about one hundred thousand people, several millions of sky maps are printed and distributed by newspapers and the associated TV live program broadcast by France 2 channel interested 1 to 3 millions spectators. Since 1991, Nuits des ´etoiles has helped to develop organisations at the local level and increased the stakeholders’ interest in general public awareness. It contributed in France to strengthen and professionalise an astronomical leisure offer

The “Ciel, miroir des cultures” exhibition: a three-year awareness campaign on the sky as a mirror of cultures

The Ciel, miroir des cultures poster-exhibition was designed by the Association Fran¸caise d’Astronomie and printed in 300 copies in 2005. Each copy is composed of 14 posters introducing the different ways human beings and societies have used the sky and the heavens in history. More than three hundred cultural events have now been using the exhibition in schools and community structures as public libraries and social centres, taking place mainly in low income urban or suburban neighbourhoods. This three-year work demonstrated the relevance of this kind of tools and events to pedagogical and social aims, specifically if the event is not limited to showing posters and also offers an opportunity for dialogue

LTR-Retrotransposons in R. exoculata and Other Crustaceans: The Outstanding Success of GalEa-Like Copia Elements

Transposable elements are major constituents of eukaryote genomes and have a great impact on genome structure and stability. They can contribute to the genetic diversity and evolution of organisms. Knowledge of their distribution among several genomes is an essential condition to study their dynamics and to better understand their role in species evolution. LTR-retrotransposons have been reported in many diverse eukaryote species, describing a ubiquitous distribution. Given their abundance, diversity and their extended ranges in C-values, environment and life styles, crustaceans are a great taxon to investigate the genomic component of adaptation and its possible relationships with TEs. However, crustaceans have been greatly underrepresented in transposable element studies. Using both degenerate PCR and in silico approaches, we have identified 35 Copia and 46 Gypsy families in 15 and 18 crustacean species, respectively. In particular, we characterized several full-length elements from the shrimp Rimicaris exoculata that is listed as a model organism from hydrothermal vents. Phylogenic analyses show that Copia and Gypsy retrotransposons likely present two opposite dynamics within crustaceans. The Gypsy elements appear relatively frequent and diverse whereas Copia are much more homogeneous, as 29 of them belong to the single GalEa clade, and species-or lineage-dependent. Our results also support the hypothesis of the Copia retrotransposon scarcity in metazoans compared to Gypsy elements. In such a context, the GalEa-like elements present an outstanding wide distribution among eukaryotes, from fishes to red algae, and can be even highly predominant within a large taxon, such as Malacostraca. Their distribution among crustaceans suggests a dynamics that follows a "domino days spreading'' branching process in which successive amplifications may interact positively

Using the Sonogashira Reaction for Preparing a New Fragment Library based on the 3-alkynylimidazo[1,2-alpha] pyridine Scaffold

International audienceBackground:The imidazo[1,2-alpha] pyridine ring has been widely studied by medicinal chemists and displays great pharmaceutical potential. Methods: In a view to prepare a library of new molecules including an imidazo[1,2-alpha] pyridine scaffold, as original fragments for the conception of novel anti-protozoal compounds, the Sonogashira crosscoupling reaction between 3-halogenoimidazo [1,2-alpha] pyridines and phenylacetylene was studied. Results: From 3-iodoimidazo[1,2-alpha] pyridine, chosen as an optimal substrate for conducting the reaction at room temperature in 2 hours, a variety of terminal alkynes was involved into the reaction, leading to a series of 16 new 3-phenyethynylimidazo [1,2-alpha] pyridines in satisfying to good yields (50-82%) and 4 additional derivatives in moderate yields (30-40%). Conclusion: Such synthetic approach appears efficient for the rapid synthesis of imidazopyridine chemical libraries. The corresponding derivatives will next be evaluated for their anti-infective properties