Paul Sabatier University

About: Paul Sabatier University is a education organization based out in Toulouse, France. It is known for research contribution in the topics: Population & Catalysis. The organization has 15431 authors who have published 23386 publications receiving 858364 citations.

Brain glucagon-like peptide–1 increases insulin secretion and muscle insulin resistance to favor hepatic glycogen storage

Abstract: Intestinal glucagon-like peptide-1 (GLP-1) is a hormone released into the hepatoportal circulation that stimulates pancreatic insulin secretion. GLP-1 also acts as a neuropeptide to control food intake and cardiovascular functions, but its neural role in glucose homeostasis is unknown. We show that brain GLP-1 controlled whole-body glucose fate during hyperglycemic conditions. In mice undergoing a hyperglycemic hyperinsulinemic clamp, icv administration of the specific GLP-1 receptor antagonist exendin 9-39 (Ex9) increased muscle glucose utilization and glycogen content. This effect did not require muscle insulin action, as it also occurred in muscle insulin receptor KO mice. Conversely, icv infusion of the GLP-1 receptor agonist exendin 4 (Ex4) reduced insulin-stimulated muscle glucose utilization. In hyperglycemia achieved by i.v. infusion of glucose, icv Ex4, but not Ex9, caused a 4-fold increase in insulin secretion and enhanced liver glycogen storage. However, when glucose was infused intragastrically, icv Ex9 infusion lowered insulin secretion and hepatic glycogen levels, whereas no effects of icv Ex4 were observed. In diabetic mice fed a high-fat diet, a 1-month chronic i.p. Ex9 treatment improved glucose tolerance and fasting glycemia. Our data show that during hyperglycemia, brain GLP-1 inhibited muscle glucose utilization and increased insulin secretion to favor hepatic glycogen stores, preparing efficiently for the next fasting state.

Initial results from the InSight mission on Mars

Abstract: NASA’s InSight (Interior exploration using Seismic Investigations, Geodesy and Heat Transport) mission landed in Elysium Planitia on Mars on 26 November 2018. It aims to determine the interior structure, composition and thermal state of Mars, as well as constrain present-day seismicity and impact cratering rates. Such information is key to understanding the differentiation and subsequent thermal evolution of Mars, and thus the forces that shape the planet’s surface geology and volatile processes. Here we report an overview of the first ten months of geophysical observations by InSight. As of 30 September 2019, 174 seismic events have been recorded by the lander’s seismometer, including over 20 events of moment magnitude Mw = 3–4. The detections thus far are consistent with tectonic origins, with no impact-induced seismicity yet observed, and indicate a seismically active planet. An assessment of these detections suggests that the frequency of global seismic events below approximately Mw = 3 is similar to that of terrestrial intraplate seismic activity, but there are fewer larger quakes; no quakes exceeding Mw = 4 have been observed. The lander’s other instruments—two cameras, atmospheric pressure, temperature and wind sensors, a magnetometer and a radiometer—have yielded much more than the intended supporting data for seismometer noise characterization: magnetic field measurements indicate a local magnetic field that is ten-times stronger than orbital estimates and meteorological measurements reveal a more dynamic atmosphere than expected, hosting baroclinic and gravity waves and convective vortices. With the mission due to last for an entire Martian year or longer, these results will be built on by further measurements by the InSight lander. Geophysical and meteorological measurements by NASA’s InSight lander on Mars reveal a planet that is seismically active and provide information about the interior, surface and atmospheric workings of Mars.

Cinnamoyl CoA reductase, the first committed enzyme of the lignin branch biosynthetic pathway: cloning, expression and phylogenetic relationships.

Abstract: Summary Cinnamoyl CoA:NADP oxidoreductase (CCR, EC 1.2.1.44) catalyzes the conversion of cinnamoyl CoA esters to their corresponding cinnamaldehydes, i.e. the first specific step in the synthesis of the lignin monomers. The cloning of a cDNA encoding CCR in Eucalyptus gunnii (EUCCR) is reported here. The identity of the EUCCR cDNA was demonstrated by comparison with peptide sequence data from purified CCR and functional expression of the recombinant enzyme in Escherichia coli. Sequence analysis revealed remarkable homologies with dihydroflavonol-4-reductase (DFR), the first enzyme of the anthocyanin biosynthetic pathway. Moreover, significant similarities were found with mammalian 3β-hydroxysteroid dehydrogenase and bacterial UDP-galactose-4-epimerase, suggesting that CCR shared a common ancestor with these enzymes and can therefore be considered as a new member of the mammalian 3β-hydroxysteroid dehydrogenase/ plant dihydroflavonol reductase superfamily. In Eucalyptus gunnii, CCR is encoded by one gene containing four introns whose positions are similar to those of introns I, II, III and V in DFR genes from dicots. In agreement with the involvement of CCR in lignification, the CCR transcript was shown to be expressed in lignified organs, i.e. root and stem tissues, and was localized mainly in young differentiating xylem. On the other hand, its abundance in Eucalyptus leaves suggests that monolignols may be precursors of end products other than lignins. This first characterization of a gene corresponding to CCR opens new possibilities to genetically engineer plants with lower lignin content. This is particularly important for woody plants such as Eucalyptus which are used for pulp making.

Bacterial spore inactivation by atmospheric-pressure plasmas in the presence or absence of UV photons as obtained with the same gas mixture

Abstract: This paper comprises two main parts: a review of the literature on atmospheric-pressure discharges used for micro-organism inactivation, focused on the inactivation mechanisms, and a presentation of our research results showing, in particular, that UV photons can be the dominant species in the inactivation process.The possibility of achieving spore inactivation through UV radiation using an atmospheric-pressure discharge or its flowing afterglow is the object of a continuing controversy. In fact, the review of the literature that we present shows that a majority of researchers have come to the conclusion that, at atmospheric pressure, chemically reactive species such as free radicals, metastable atoms and molecules always control the inactivation process, while UV photons play only a minor role or no role at all. In contrast, only a few articles suggest or claim that UV photons coming from atmospheric-pressure discharges can, in some cases, inactivate micro-organisms, but the experimental data presented and the supporting arguments brought forward in that respect are relatively incomplete.Using a dielectric-barrier discharge operated at atmospheric pressure in an N2–N2O mixture, we present, for the first time, experiments where micro-organisms are subjected to plasma conditions such that, on the one hand, UV radiation is strong or, on the other hand, there is no UV radiation, the two different situations being obtained with the same experimental arrangement, including the same gas mixture, N2–N2O. To achieve maximum UV radiation, the concentration of the oxidant molecule (N2O) added to N2 needs to be tuned carefully, resulting then in the fastest inactivation rate. The concentration range of the oxidant molecule in the mixture for which the UV intensity is significant is extremely narrow, a fact that possibly explains why such a mode of plasma sterilization was not readily observed. The survival curves obtained under dominant UV radiation conditions are, as we show, akin to those recorded at reduced pressure. Relatively fast spore inactivation can also be obtained under no UV radiation as a result of radicals diffusing deeply inside the spores, leading to oxidative lethal damage.