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International audience; In Austral Africa, no remains of domestic caprines (sheep Ovis aries and goat Capra hircus) has never been found in archaeological assemblages. This suggests that those domestic animals have been introduced from the Near East to East Africa and then to the southern part of the continent (MacHugh, Larson & Orlando 2017, Vigne 2011). o Classical morphological determination of caprines from bone remains is often tricky due to the similarities between close related species as well as between domestic and wild species, fragmentation of the remains and bone diagenesis. o Paleoproteomics has revealed as a powerful approach for the distinction of domestic caprines (Buckley et al. 2010). We used this technique on remains from two Austral African sites considered as the oldest pastoral sites of the region: Leopard Cave in Namibia (Pleurdeau et al. 2012) and Toteng in Botswana (Robbins et al. 2008). Our objective was to ascertain the presence or absence of domestic animals at these sites. o Three different sample preparation protocols were tested in order to identify the best conditons for remains from arid environment. Bottom-up proteomics analysis was performed on an ESI-Q-TOF device with a data dependent autoMS/MS method. Modern samples from referential collections (MNHN) were also analyzed to constitute a database of unreported diagnostic peptides for species identification.

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International audience; The Mediterranean marine sponge Spongia officinalis has been reported as a rich source of secondary metabolites and also as a bioindicator of water quality given its capacity to concentrate trace metals. In this study, we evaluated the chemical diversity within 30 S. officinalis samples collected over three years at two sites differentially impacted by anthropogenic pollutants located near Marseille (South of France). Untargeted liquid chromatography-mass spectrometry (LC-MS) metabolomic profiling (C18 LC, ESI-Q-TOF MS) combined with XCMS Online data processing and multivariate statistical analysis revealed 297 peaks assigned to at least 86 compounds. The spatio-temporal metabolite variability was mainly attributed to variations in relative content of furanoterpene derivatives. This family was further characterized through LC-MS/MS analyses in positive and negative ion modes combined with molecular networking, together with a comprehensive NMR study of isolated representatives such as demethylfurospongin-4 and furospongin-1. The MS/MS and NMR spectroscopic data led to the identification of a new furanosesterterpene, furofficin (2), as well as two derivatives with a glycinyl lactam moiety, spongialactam A (12a) and B (12b). This study illustrates the potential of untargeted LC-MS metabolomics and molecular networking to discover new natural compounds even in an extensively studied organism such as S. officinalis. It also highlights the effect of anthropogenic pollution on the chemical profiles within the sponge.

The amyloid peptide Abeta is the major component of senile plaques, a characteristic brain lesion of Alzheimer's disease. Abeta assembly into fibrillar structures is assumed to be initiated by a conformational transition of the peptide from an alpha-helix or random to a beta-sheet secondary structure. Involvement of Zn2+ ions in this transconformation has been strongly suggested. The 1-16 Abeta N-terminal region : D1AEFR5HDSGY10EVHHQ15K (Abeta (1-16)) corresponds to the amino acid sequence between the cleavage sites of beta- and alpha-secretases, the former releasing Abeta while the latter only releases nonamyloidogenic peptides. The 1-16 N-terminal sequence contains the three histidines hypothesized to be implicated in Zn2+ binding, together with the three mutations (R5G, Y10F and H13R) that distinguish the human Abeta from the rat protein. As rat does not develop Alzheimer's disease and Abeta rat is not able to form amyloid deposits, we investigated the role of the 1-16 Abeta region in the transconformation, and focussed particularly on the conformational behavior of this fragment upon addition of Zn2+ ions. A conformational study of Abeta(1-16)human has been undertaken by circular dichroism and NMR spectroscopy. Depending on the medium, Abeta(1-16) human adopted either a random coil or an alpha-helical structure including a turn centered at D7-S8. The conformational transition toward beta-sheet occuring in the presence of Zn2+ ions that has been previously observed by CD was here examined by NMR. The zinc-bound form, which exhibits strong specific induced shifts affecting histidine residues was further characterized. The whole results are compared to those obtained with Abeta(1-16)rat, allowing to discuss the influence of the rat mutations on the conformation and Zn2+ binding properties.