Evidence of seasonal reproduction, laying site fidelity, and oviposition synchronicity in the critically endangered endemic Manapany Day Gecko (Phelsuma inexpectata) from Reunion Island (western Indian Ocean)

The reproductive phenology of tropical geckos varies considerably between species. We investigated the reproductive timing of Phelsuma inexpectata, a critically endangered tropical squamate endemic to Reunion Island (western Indian Ocean). From February 2018 to August 2020 (30 months), we carried out monthly monitoring of laying sites. Phelsuma inexpectata exhibited a seasonal reproductive pattern, with breeding activity from the end of the austral winter to the end of the austral summer. We observed intra- and interannual synchronicity of oviposition in September. The seasonal  reproductive pattern appears to be synchronized with optimal environmental conditions (temperatures, food resources) for the survival of eggs and hatchlings. Females deposited their eggs in communal laying sites (up to 9 eggs) and exhibited interannual laying site fidelity (50% of the laying sites were reused in the second breeding season). Minimum and maximum incubation periods (± SD) were 69 ± 24 days and 115 ± 25 days, respectively. Our study provides the first description of the Manapany Day Gecko reproduction in the wild and highlights for the first time the very high synchronicity of oviposition in the genus Phelsuma. These results will be very useful to improve the conservation of this species, in particular with regard to the timing of predator control, designing monitoring protocols for breeding and survival parameters, and implementing a captive rearing program for hatchlings

Evidence of seasonal reproduction, laying site fidelity, and oviposition synchronicity in the critically endangered endemic Manapany Day Gecko (Phelsuma inexpectata) from Reunion Island (western Indian Ocean)

International audienceThe reproductive phenology of tropical geckos varies considerably between species. We investigated the reproductive timing of Phelsuma inexpectata, a critically endangered tropical squamate endemic to Reunion Island (western Indian Ocean). From February 2018 to August 2020 (30 months), we carried out monthly monitoring of laying sites. Phelsuma inexpectata exhibited a seasonal reproductive pattern, with breeding activity from the end of the austral winter to the end of the austral summer. We observed intra-and interannual synchronicity of oviposition in September. The seasonal reproductive pattern appears to be synchronized with optimal environmental conditions (temperatures, food resources) for the survival of eggs and hatchlings. Females deposited their eggs in communal laying sites (up to 9 eggs) and exhibited interannual laying site fidelity (50% of the laying sites were reused in the second breeding season). Minimum and maximum incubation periods (± SD) were 69 ± 24 days and 115 ± 25 days, respectively. Our study provides the first description of the Manapany Day Gecko reproduction in the wild and highlights for the first time the very high synchronicity of oviposition in the genus Phelsuma. These results will be very useful to improve the conservation of this species, in particular with regard to the timing of predator control, designing monitoring protocols for breeding and survival parameters, and implementing a captive rearing program for hatchlings

Effect of uridine protecting groups on the diastereoselectivity of uridine-derived aldehyde 5’-alkynylation

The 5’-alkynylation of uridine-derived aldehydes is described. The addition of alkynyl Grignard reagents on the carbonyl group is significantly influenced by the 2’,3’-di-O-protecting groups (R1): O-alkyl groups led to modest diastereoselectivities (65:35) in favor of the 5’R-isomer, whereas O-silyl groups promoted higher diastereoselectivities (up to 99:1) in favor of the 5’S-isomer. A study related to this protecting group effect on the diastereoselectivity is reported

Bacterial Transferase MraY, a Source of Inspiration towards New Antibiotics

International audienceThe bacterial resistance to antibiotics constitutes more than ever a severe public health problem. The enzymes involved in bacterial peptidoglycan biosynthesis are pertinent targets for developing new antibiotics, notably the MraY transferase that is not targeted by any marketed drug. Many research groups are currently working on the study or the inhibition of this enzyme. After a concise overview of the role, mechanism and inhibition of MraY, the structure-activity relationships of 5'-triazole-containing aminoribosyluridine inhibitors, we previously synthetized, will be presented. The recently published MraY X-ray structures allowed us to achieve a molecular virtual high-throughput screening of commercial databases and our in-house library resulting in the identification of promising compounds for the further development of new antibiotics

5'-Methylene-triazole-substituted-aminoribosyl uridines as MraY inhibitors: synthesis, biological evaluation and molecular modeling.

International audienceThe straightforward synthesis of 5'-methylene-[1,4]-triazole-substituted aminoribosyl uridines is described. Two families of compounds were synthesized from a unique epoxide which was regioselectively opened by acetylide ions (for compounds II) or azide ions (for compounds III). Sequential diastereoselective glycosylation with a ribosyl fluoride derivative, Cu(i)-catalyzed azide-alkyne cycloaddition (CuAAC) with various complementary azide and alkyne partners afforded the targeted compounds after final deprotection. The biological activity of the 16 resulting compounds together with that of 14 previously reported compounds I, lacking the 5' methylene group, was evaluated on the MraY transferase activity. Out of the 30 tested compounds, 18 compounds revealed MraY inhibition with IC50 ranging from 15 to 150 μM. A molecular modeling study was performed to rationalize the observed structure-activity relationships (SAR), which allowed us to correlate the activity of the most potent compounds with an interaction involving Leu191 of MraYAA. The antibacterial activity was also evaluated and seven compounds exhibited a good activity against Gram-positive bacterial pathogens with MIC ranging from 8 to 32 μg mL(-1), including the methicillin resistant Staphylococcus aureus (MRSA)

Plantes envahissantes pour les milieux naturels de Nouvelle-Calédonie

Menaces pour la biodiversité, contraintes pour les agriculteurs et les activités humaines, les plantes envahissantes constituent un problème de plus en plus évoqué à travers le monde. Partant de ce constat, l'APICAN (Agence pour la Prévention et l'Indemnisation des Calamités Agricoles ou Naturelles) et ses partenaires ont soutenu l'élaboration de ce guide dans le but de faire connaitre, du plus grand nombre, les problématiques liées aux plantes envahissantes, les moyens de les identifier et les techniques à mettre en oeuvre pour les contrôler. Il s'adresse aux services techniques des communes et des réserves naturelles terrestres, aux exploitants agricoles, aux professionnels des espaces verts mais aussi aux citoyens sensibilisés à la protection de l'environnement. Ce guide décrit 81 espèces végétales envahissantes principales des milieux naturels de Nouvelle-Calédonie (Grande Terre et îles Loyauté). Le texte donne la description, la biologie, la répartition et les moyens de contrôler chaque espèce. Des photographies accompagnent chaque fiche pour faciliter l'identification des plantes

Le traitement lexicographique des noms propres

Les articles publiés dans ce numéro spécial de la revue CORELA ont été sélectionnés parmi les communications effectuées durant le colloque consacré au traitement lexicographique des noms propres qui s’est tenu le 25 mars 2005 à l’Université François-Rabelais de Tours. Le comité de lecture international était composé de Claire Agafonov, Jean-Yves Antoine, Thierry Grass, Cvetana Krstev, Denis Maurel, Nathalie Rossi-Gensane, Mickaël Tran et Duško Vitas