Late Miocene onset of the modern Antarctic Circumpolar Current

The Antarctic Circumpolar Current plays a pivotal role in global climate through its strong influence on the global overturning circulation, ocean heat and CO uptake. However, when and how the Antarctic Circumpolar Current reached its modern-like characteristics remains disputed. Here we present neodymium isotope and sortable silt records from sediment cores in the Southwest Pacific and South Indian oceans spanning the past 31 million years. Our data indicate that a circumpolar current like that of today did not exist before the late Miocene cooling. These findings suggest that the emergence of a homogeneous and deep-reaching strong Antarctic Circumpolar Current was not linked solely to the opening and deepening of Southern Ocean Gateways triggering continental-scale Antarctic Ice Sheet expansion during the Eocene–Oligocene Transition (∼34 Ma). Instead, we find that besides tectonic pre-conditioning, the expansion of the Antarctic Ice Sheet and sea ice since the middle Miocene Climate Transition (∼14 Ma) played a crucial role. This led to stronger density contrast and intensified Southern Westerly Winds across the Southern Ocean, establishing a vigorous deep-reaching circumpolar flow and an enhanced global overturning circulation, which amplified the late Cenozoic global cooling.This research used samples provided by the International Ocean Discovery Program (IODP). We acknowledge the staff and shipboard party from Leg 28 and Leg 119. We thank the staff at the Gulf Coast core repository (GCR) for curating these cores and for assistance in core handling and shipping. Funding for this research is provided by the Spanish Ministry of Economy, Industry and Competitivity (grant CTM2017-89711-C2-1/2-P; PID2021-126495NB-C31), co-funded by the European Union through FEDER funds. D.E. was funded by the Alexander S. Onassis Public Benefit Foundation PhD research grant (F ZL 016-1/2015-2016), by MOPGA postdoctoral visiting fellowship programme funded by the French Ministry of Europe and Foreign Affairs (grant MOPGA postdoc-3–5669831615), by the Juan de la Cierva-formation postdoctoral research grant (FJC2020-043650-I) funded by MCIN/AEI/ 10.13039/501100011033 and the ‘European Union NextGenerationEU/PRTR’ and by the UK Research and Innovation Engineering and Physical Sciences Research Council (grant number EP/X02623X/1). D.E. received additional funding from an ECORD research grant and IODP-France. I.S. and A.K. were supported by the Australian Research Council Special Research Initiative for Antarctic Gateway Partnership (project ID SR140300001) and the Australian Research Council’s Discovery Project 180102280. Model runs were undertaken with the assistance of resources from the National Computational Infrastructure (NCI), which is supported by the Australian Government. We thank the Paleomagnetic Laboratory CCiTUB-Geo3Bcn CSIC for the support on palaeomagnetic analysis. The GRC Geociències Marines thanks the Generalitat de Catalunya for the Grups de Recerca Consolidats grant 2021SGR01195 and for the ICREA-Academia award to I.C. This paper is a contribution to the SCAR INSTANT Programme.Peer reviewe

In vitro comparison of whey protein isolate and hydrolysate for their effect on glucose homeostasis markers

International audiencePre-hydrolysis of whey proteins modify the intestinal peptidome, leading to a greater GLP-1 secretion after in vitro gastrointestinal digestion. Digested whey protein hydrolysate inhibits DPP-IV activity after intestinal barrier passage

Geodynamic evolution of the Tethyan lithosphere as recorded in the Spontang Ophiolite, South Ladakh ophiolites (NW Himalaya, India)

The Spontang Ophiolite complex represents the most complete ophiolite sequence amongst the South Ladakh ophiolites and comprises mantle rocks (depleted harzburgites, dunites and minor lherzolites) as well as crustal rocks (basalt, isotropic gabbros, layered gabbros etc.). In the present study, detailed geochemistry (whole rock as well as mineral chemistry) and Sr-Nd isotopic analyses of thirty-six ultramafic- mafic samples have been attempted to constraint the evolution and petrogenetic history of the Tethyan oceanic crust. Major, trace-element and REE patterns of the peridotites and their minerals indicate that the lherzolites experienced lower degrees of partial melting resembling abyssal peridotites (at higher temperatures, T = ∼1216 °C) than the harzburgites (6%–8% versus 15%–17%). Elevated ε(t) and variable Sr/Sr(t) ratios along with REE patterns suggest that the Spontang mafic rocks display N-MORB affinity with negligible participation of oceanic sediments in their genesis are originated from a depleted upper mantle with little contribution from subduction-related fluids. MORB-type Neotethyan oceanic crust is associated with the earliest phase of subduction (of older Jurassic age) through which a younger intra-oceanic island arc (Spong arc) subsequently developed. Harzburgites REE display typical U-shaped patterns, suggesting that these rocks have been metasomatized by LREE-enriched fluids. On the other side, mafic rocks are characterized by heterogeneous (Nb/La) and (Hf/Sm) and relatively homogeneous ε(t), indicating interaction of subduction-related melts with the upper mantle during the initiation of subduction, in Early Cretaceous times.The authors thank the Head, Department of Geology and Interdisciplinary School of Science (IDSS), SPPU for providing necessary facilities. MKJ acknowledges the financial support received from Science Education and Research Board (SERB) and Department of Science and Technology (DST) by way of its Young Scientist Scheme (Ref. No. SR/FTP/ES-2/2014) Women's scientist scheme (Ref No. SR/WOS-A/EA-14/2017). S. Mounic and A. Marquet respectively from Toulouse TIMS and ICPMS facilities. RT acknowledges a “Juan de la Cierva-formación” Fellowship (FJC2018-036729) granted by the Spanish Ministry of Science and Innovation and co-funded by the European Development Fund and the European Social Fund.

Digested casein phosphopeptides impact intestinal calcium transport in vitro

International audienceA casein hydrolysate enriched in CPPs underwent in vitro digestion and was incubated with an IB model to monitor calcium uptake and transport. The dCPPs enhanced paracellular calcium transport. CPPs capable of crossing the IB were identified

Identification, production and bioactivity of casein phosphopeptides – A review

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In vitro transport of juncusol isolated from Juncus inflexus across intestinal Caco-2-HT29-MTX cells monolayer.

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An Exploratory Study of the Role of Dietary Proteins in the Regulation of Intestinal Glucose Absorption

International audienceSeveral studies have demonstrated that high protein diets improve glucose homeostasis. Nevertheless, the mechanisms underlying this effect remain elusive. This exploratory study aims to screen and compare the acute effects of dietary proteins from different sources on intestinal glucose absorption. Six dietary proteins from various sources were thus selected and digested thanks to the INFOGEST static gastrointestinal digestion protocol. The digested proteins were able to decrease intestinal glucose absorption in vitro and ex vivo. Moreover, acute ingestion of casein and fish gelatin led to improved glucose tolerance in Wistar rats without significant effect on insulin secretion. In parallel, GLUT2 mRNA expression in enterocytes was decreased following short-term incubation with some of the digested proteins. These results strengthen the evidence that digested protein-derived peptides and amino acids are key regulators of glucose homeostasis and highlight their role in intestinal glucose absorption

Impact of industrial process on gastrointestinal digestion of milk micellar caseins and development of low bitterness casein hydrolysates

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PeptidoMILK: an academic/industrial collaboration story through the “All in Pep labcom” and the ProteinoPepS industrial chair

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