Time filter

Source Type

Rebuffat S.,French Natural History Museum
Biochemical Society Transactions

Probably the oldest and most widespread antimicrobial strategy in living organisms is the use of antimicrobial peptides. Bacteria secrete such defence peptides, termed bacteriocins, that they use for microbial competitions. Microcins are bacteriocins of less than 10 kDa produced by Escherichia coli and related enterobacteria through the ribosomal pathway. They are synthesized as linear precursors, which can further undergo complex post-translational modifications resulting from dedicated maturation enzymes encoded in the microcin gene clusters, and are processed by proteolytic cleavage. Microcins exert potent bactericidal activities that use subtle and clever mechanisms to cross outer and inner membranes of Gramnegative bacteria. To cross the outer membrane, siderophore-microcins hijack receptors involved in iron acquisition. The lasso-peptide microcin J25, which is characterized by a knotted arrangement where the C-terminal tail is threaded through an N-terminal macrolactam ring, uses a hydroxamate siderophore receptor and the inner-membrane protein SbmA for import in sensitive bacteria, where it inhibits bacterial transcription through binding to RNAP (RNA polymerase). Microcin C produced as a heptapeptide adenylate, requires an outer-membrane porin and an inner-membrane ABC (ATP-binding-cassette) transporter to reach the cytoplasm of target bacteria, where it is processed by proteases into a non-hydrolysable aspartyladenylate analogue. Therefore, despite showing different killing mechanisms and the absence of any structural homology, microcins have the common characteristic to use Trojan horse strategies to destroy their competitors. They offer new and promising tracks for further design and engineering of novel efficient antibiotics. ©The Authors Journal compilation ©2012 Biochemical Society. Source

Dambricourt Malasse A.,French Natural History Museum
Comptes Rendus - Palevol

This paper presents the first Indo-French Prehistorical Mission in the Himalayan foothills, northwestern India, and introduces the results of the multidisciplinary research program "Siwaliks" under the patronage of Professor Yves Coppens, from the Collège de France and Académie des Sciences, France. This program is dedicated to the discovery of cut marks on mineralized bovid bones collected among vertebrate fossils in a fluviatile formation named "Quranwala zone" in the Chandigarh anticline, near the village Masol, and located just below the Gauss-Matuyama polarity reversal (2.58 Ma). Artefacts (simple choppers, flakes) have been collected in and on the colluviums. This important discovery questions the origins of the hominins which made the marks. © 2015 Académie des sciences. Source

This article aims to summarize the present archaeo(zoo)logical knowledge and reflections on the origins of Neolithic animal domestication. It targets the main characteristics of early Neolithic animal domestication set against a backdrop of two complementary scales, namely the global and macro-regional scales (the latter using the example of the Near East). It discusses the conceptual and methodological issues, arguing in favor of an anthropozoological approach taking into account the intentions and the dynamics of human societies and critically analyzes the reductionist neo-Darwinian concepts of co-evolution and human niche construction. It also provides a brief discussion on the birth of ungulate domestication and its roots, as well as appropriate bibliographic references to enlighten the current status of domestication research. © 2010 Académie des sciences. Source

Janvier P.,French Natural History Museum

The interrelationships between major living vertebrate, and even chordate, groups are now reasonably well resolved thanks to a large amount of generally congruent data derived from molecular sequences, anatomy and physiology. But fossils provide unexpected combinations of characters that help us to understand how the anatomy of modern groups was progressively shaped over millions of years. The dawn of vertebrates is documented by fossils that are preserved as either soft-tissue imprints, or minute skeletal fragments, and it is sometimes difficult for palaeontologists to tell which of them are reliable vertebrate remains and which merely reflect our idea of an ancestral vertebrate. © 2015 Macmillan Publishers Limited. All rights reserved. Source

Zazzo A.,French Natural History Museum
Rapid communications in mass spectrometry : RCM

Stable sulphur isotope ratios ((34)S/(32)S) in animal tissues have been suggested as a tracer of coastal residency of terrestrial animals, but data are lacking that quantify the inland range of the sulphur coastal signal and the effects of seasonality. Here, we present δ(34)S measurements of sheep wool collected seasonally on eight farms across Ireland and wool samples collected opportunistically along the west and east coasts. We observed large (>10‰) δ(34)S differences across the island and we show that wool δ(34)S values were negatively correlated with distance to the west coast. We propose that this is due to the predominantly (south-)westerly airflow, possibly combined with the influence of anthropogenic sulphur deposited from the east. While essentially all the sulphur contained in west-coast wool is of marine origin, relatively high δ(34)S values were still measured >100km inland, suggesting that marine sulphur can be carried over long distances. Seasonal variations are small at the individual level for sedentary grazing animals. We conclude that sulphur isotopes ratios measured in archival keratinous tissues can be used to describe regional δ(34)S isoscapes primarily defined by distance to coasts and thus provide a tool to detect short-term movements of domestic, feral and wild animals within such isoscapes. Copyright © 2011 John Wiley & Sons, Ltd. Source

Discover hidden collaborations