53161 research outputs found
Sort by
LCO Receptors Involved in Arbuscular Mycorrhiza Are Functional for Rhizobia Perception in Legumes
No full textBacterial lipo-chitooligosaccharides (LCOs) are key mediators of the nitrogen-fixing root nodule symbiosis (RNS) in legumes. The isolation of LCOs from arbuscular mycorrhizal fungi suggested that LCOs are also signaling molecules in arbuscular mycorrhizal (AM). However, the corresponding plant receptors have remained uncharacterized. Here we show that petunia and tomato mutants in the LysM receptor-like kinases LYK10 are impaired in AM formation. Petunia and tomato LYK10 proteins have a high affinity for LCOs (Kd in the nM range) comparable to that previously reported for a legume LCO receptor essential for the RNS. Interestingly, the tomato and petunia LYK10 promoters, when introduced into a legume, were active in nodules similarly to the promoter of the legume orthologous gene. Moreover, tomato and petunia LYK10 coding sequences restored nodulation in legumes mutated in their orthologs. This combination of genetic and biochemical data clearly pinpoints Solanaceous LYK10 as part of an ancestral LCO perception system involved in AM establishment, which has been directly recruited during evolution of the RNS in legumes
Impact des représentations du sang menstruel sur le choix contraceptif des femmes
No full textObjectifs Étudier les représentations psychiques et le vécu du sang menstruel chez des femmes et leur impact sur le choix d’une méthode contraceptive, avec ou sans hémorragie de privation.
Méthodes Étude qualitative par entretiens semi-dirigés auprès de femmes majeures sous contraception.
Résultats Vingt-trois entretiens ont été réalisés parmi des femmes d’âge et de classes socioéconomiques variés. Trois thèmes ont été abordés : l’expérience de la ménarche, la représentation et le vécu du sang menstruel, et la représentation et le vécu de l’aménorrhée induite par une contraception. La ménarche a été une expérience négative et décisive dans les représentations et le vécu du sang menstruel pour la majorité d’entre elles. Concernant le saignement menstruel, deux profils de groupes de femmes ont été observés. Celles ayant une représentation positive du sang menstruel le considéraient comme nécessaire à la purification de leur corps ainsi qu’à la procréation et étaient réticentes à l’idée d’une aménorrhée induite par leur contraception. Celles ayant une représentation négative du sang menstruel le considéraient comme une source de souffrance physique et morale et acceptaient plus facilement l’idée d’avoir une aménorrhée induite par leur contraception, l’aménorrhée étant considérée alors comme un traitement ou une libération. Certains facteurs évolutifs tels que l’âge et la situation familiale des femmes influençaient leurs représentations du sang menstruel et de l’aménorrhée induite.
Conclusion Le choix d’une aménorrhée induite ou non par la contraception semble être propre à chaque femme avec des représentations psychiques du sang menstruel indépendantes de la classe socioéconomique. Les résultats de cette étude mettent en évidence l’effet de la représentation et du vécu du sang menstruel d’une femme sur son choix contraceptif.Objectives To study the psychic self-representations and experiences of menstrual blood in women and their impact on the choice of a contraceptive method, with or without amenorrhea.
Methods Qualitative study based on semi-structured interviews with French women over age 18, under contraception. Results Twenty-three interviews were conducted with women of various ages and socio-economic classes. Three themes have been studied: the menarche experience, the representation and experience of menstrual blood, and the representation and experience of amenorrhea induced by contraception. Menarche has been a negative experience for most of them, and menarche is known to influence menstrual self-representation. About menstrual bleeding, two profiles of women could be described. Those with a positive self-representation of menstrual blood considered it necessary for the purification of their bodies as well as for procreation and were reluctant to the idea of amenorrhea induced by their contraception. Those with a negative representation of menstrual blood considered it as a source of physical and mental suffering and accepted the idea of having amenorrhea induced by their contraception, amenorrhea being considered as a treatment or a release.
Conclusion The choice of a contraception with or without a induced-amenorrhea seems to be specific to every woman and depends on there self-psychic representation of menstrual blood, independently from their socio-economic class. The results of this study highlighted the effect of women's psychic representations and experience of menstrual blood on their contraceptive choice
The effect of time and method of storage on the chemical composition, pepsin-cellulase digestibility, and near-infrared spectra of whole-maize forage
No full textThis study examined the effects of long-term storage conditions on the chemical composition, pepsin-cellulase dry matter digestibility (PCDMD), and visible (VIS)/near infrared spectra (NIR) of forage. Eighteen samples of different whole-crop maize varieties originally harvested in 1987 were used. After drying, these samples were analyzed in the laboratory for ash, crude protein (CP), structural carbohydrates, total soluble carbohydrates (TSC), starch and PCDMD, and the remaining samples were stored frozen (at −20°C) or at barn temperature (ambient temperatures ranged from −8.5 °C to 27.1 °C). In 2016, the samples were analyzed for ash, CP, structural carbohydrates, TSC, starch and PCDMD. The visible/NIR spectra of both storage methods were obtained. Chemical composition and PCDMD analyses revealed significant differences (p 0.05). After sample harvesting in 1987, the analyses were compared with those in 2016. It was found that the post-harvest TSC and ash content were higher (p < 0.05) and lower (p < 0.05), respectively, during 2016. No significant differences were found for starch and PCDMD. Important differences between the VIS/NIR spectra of both storage methods were obtained in the VIS segment, particularly in the area between 630 and 760 nm. We concluded that storing dry forage samples at ambient temperature for a very long time (29 years) did not change their nutritive value compared to the values obtained before storage
Why Were More Than 200 Subjects Required to Demonstrate the Bioequivalence of a New Formulation of Levothyroxine with an Old One?
No full textwas licensed in France in 2017, with the objective of avoiding the stability deficiencies of an existing licensed formulation. Before launching the new formulation, an average bioequivalence (ABE) trial was conducted, having enrolled 204 subjects and selected for interpretation a narrow a priori bioequivalence range of 0.90-1.11. Bioequivalence was concluded. In a previous publication, we questioned the ability of an ABE trial to guarantee the switchability within patients of the new and old levothyroxine formulations. It was suggested that the two formulations should be compared using the conceptual framework of individual bioequivalence. The present paper is a response to those claiming that, despite the fact that ABE analysis does not formally address the switchability of the two formulations, future patients will nevertheless be fully protected. The basis for this claim is that the ABE study was established in a large trial and analyzed using a stringent a priori acceptance interval of equivalence. These claims are questionable, because the use of a very large number of subjects nullifies the implicit precautionary intention of the European guideline when, for a Narrow Therapeutic Index drug, it recommends shortening the a priori acceptance interval from 0.80-1.25 to 0.90-1.11
Sex chromosome and sex locus characterization in the goldfish, Carassius auratus
No full textBackground: Goldfish is an important model for various areas of research, including neural development and behavior and a species of significant importance in aquaculture, especially as an ornamental species. It has a male heterogametic (XX/XY) sex determination system that relies on both genetic and environmental factors, with high temperatures being able to produce female-to-male sex reversal. Little, however, is currently known on the molecular basis of genetic sex determination in this important cyprinid model. We used sequencing approaches to better characterize sex determination and sex-chromosomes in goldfish.
Results: Our results confirmed that sex determination in goldfish is a mix of environmental and genetic factors and that its sex determination system is male heterogametic (XX/XY). Using reduced representation (RAD-seq) and whole genome (pool-seq) approaches, we characterized sex-linked polymorphisms and developed male specific genetic markers. These male specific markers were used to distinguish sex-reversed XX neomales from XY males and to demonstrate that XX female-to-male sex reversal could even occur at a relatively low rearing temperature (18°C), for which sex reversal has been previously shown to be close to zero. We also characterized a relatively large non-recombining region (∼11.7 Mb) on goldfish linkage group 22 (LG22) that contained a high-density of male-biased genetic polymorphisms. This large LG22 region harbors 373 genes, including a single candidate as a potential master sex gene, i.e., the anti-Mullerian hormone gene (amh). However, no sex-linked polymorphisms were detected in the goldfish amh gene or its 5 kb proximal promoter sequence.
Conclusions: These results show that goldfish have a relatively large sex locus on LG22, which is likely the goldfish Y chromosome. The presence of a few XX males even at low temperature also suggests that other environmental factors in addition to temperature could trigger female-to-male sex reversal. Finally, we also developed sex-linked genetic markers in goldfish, which will be important for future research on sex determination and aquaculture applications in this species
Chicken seme cryopreservation and use for the restoration of rare genetic resources
No full textFor the past 50 yr, practices for ex situ preservation of endangered breeds have been extended. Semen and primordial germ cells, gonadic tissues have been frozen to create genetic stocks of chicken genetic diversity in cryobanks. Semen cryopreservation stays the preferred method since it is not invasive. Many protocols have been developed to cryopreserve chicken semen, but they give highly variable success rate. The aim of the present study was to standardize and prove the effectiveness of semen long-term storage for the restitution of lost families. We showed that semen straws stored for 18 yr in liquid nitrogen did not lose their fertilizing ability. We demonstrated the usefulness of cryopreserved semen stored in the French National Cryobank for the recovery of families of a subfertile experimental chicken line. In order to highlight the standardization of the cryopreserved method, different cryoprotectant protocols were also tested on a rare breed, freezing/thawing and insemination conditions were controlled. The best results were obtained using glycerol protocol, a sperm dilution of 1:4 (semen:extender). The insemination dose of 200 million sperm/female was as efficient as 400 million of sperm. Altogether, these results demonstrated the effectiveness of chicken semen long-term storage for the restoration of lost genetic resources and highlighted the importance of standardized chicken semen cryopreservation using procedures combining biophysical (cryoprotectants, freezing/thawing conditions) and zootechnical (artificial insemination) features
Etude consommateurs sur les produits traditionnels de porcs de race locale : attentes et évaluation hédonique
No full textAssessing consumers’ acceptability of traditional pork products (TPP) from local breeds is part of evaluating the sustainability of local chains. Expectations and hedonic perception of Protected Designation of Origin (PDO) Noir de Bigorre (NB) dry-cured ham produced from the pure Gascon breed were assessed. The study was conducted in Toulouse (France), as an expanding market for TPP, with 124 consumers who regularly purchased TPP (quota sampling method). Three products were used: “NB-PDO dry-cured ham 24-month curing – local pig breed in extensive system” (NB24), “NB-PDO dry-cured ham 36-month curing – local pig breed in extensive system” (NB36) as an innovative TPP to enhance sensory quality, and “Iberian ham – 50% Iberian pig” (IB) as a competing product. Following the expectation disconfirmation theory, the sensory test included three phases: blind (tasting without information), expected (product description only) and actual liking (tasting with information), using a 9-point scale from 1 (extremely dislike) to 9 (extremely like). Data were analysed using a mixed linear model including the effects of product, phase, interaction between product and phase, consumer session as random, and considering repeated measures within consumer. The blind hedonic test showed no differences (P>0.05) among products, which all had high blind liking scores (6.7-6.8). Product description strongly influenced expected liking (P<0.001), with a higher score for NB36 than NB24 (7.8 vs 7.2, respectively, P<0.05) and the lowest score for IB (5.2). The informed hedonic test showed higher actual liking scores for NB36 and NB24, which were similar, than for IB (7.4 and 7.2 vs 5.9, respectively, P<0.001). Both NB hams had higher actual liking than blind liking scores (P<0.05), denoting a positive effect of information on acceptability. Actual liking was similar to expected liking for NB24, indicating fulfilment of hedonic expectations. In contrast, actual liking was lower than blind liking for IB (P<0.05). This study will be supplemented by a study of consumer preferences and willingness to pay
Relocaliser la filière bois française : une bonne idée pour le climat
No full textFaut-il relocaliser la filière bois ? Quel serait l’impact d’une transformation locale du bois, en utilisant les résidus de cette transformation pour produire du bois industrie ou bois-énergie
par exemple ?[br/]
Alors que la filière forêt-bois est marquée par un déficit commercial structurel de 6 milliards d’euros, notamment lié à une exportation des produits bruts (grumes) et une importation des produits-bois semi-transformés et transformés (par exemple sciages et placages), un scénario de transformation locale des produits-bois permettrait d’allier intérêt économique et climatique. Se basant sur cette option
déjà préconisée par plusieurs documents de politiques publiques, I4CE se propose d’apporter une première
estimation chiffrée de l’impact d’un tel scénario du point de vue climatique.
L’intérêt climatique d’une telle option n’est pas évident. Car si un scénario de relocalisation conduit à une baisse du transport international de marchandise de la filière, et donc des émissions associées, il pourrait aussi diminuer les effets de substitution. A l’heure actuelle, la France importe beaucoup de produits transformés, et ce sont les pays exportateurs de ces produits qui bénéficient de l’utilisation des résidus de la transformation du bois brut, en partie pour produire de l’énergie ou des matériaux transformés
(papier, cartons, panneaux, …). Une évaluation des gains climatiques implique donc de prendre en compte l’impact sur les émissions des autres pays.[br/]
Dans cette étude, l’Institut de l’économie pour le climat (I4CE) fait tout d’abord le point sur les échanges commerciaux de la filière bois française et sur les différents effets de substitution. Pour rappel et de manière simplifiée, l’effet de substitution désigne les émissions évitées si un produit-bois est utilisé à la place d’un produit plus émetteur en termes de GES. Ainsi, I4CE estime qu’à l’heure actuelle, les produits-bois importés
permettent d’éviter environ 5 MtCO2. Si on s’intéresse aux exportations par la France, l’utilisation de produits-bois permet d’éviter l’émission de 7 MtCO2 chez nos voisins. Cependant, près d’un cinquième de ces émissions évitées sont « réémises » par le transport international de ces produits-bois.
L’étude apporte ensuite des éléments chiffrés pour répondre à la question : est-ce une bonne idée pour le climat de relocaliser la filière bois française ? En exploitant les données commerciales de la filière, I4CE a développé différents scénarios de relocalisation du bois et évalué leur impact CO2.
Il en ressort que, même avec des hypothèses conservatrices, la relocalisation d’une partie des activités de la
filière représente un gain pour le climat. Si elle induit une hausse des émissions dans les autres pays, celles-ci sont globalement compensées par l’utilisation accrue de boisénergie en France et – surtout – la réduction du transport international.
La relocalisation de la filière bois, associée à une bonne valorisation énergétique des résidus de transformation du bois, permettrait de disposer de plus de biomasse en France. Combien ? On estime dans cette étude que cela représenterait jusqu’à 16 % de l’objectif de mobilisation de la biomasse associé au prélèvement supplémentaire 12 Mm3 /an prévu en 2026 par le Plan National Forêt-Bois, ce qui permettrait de réduire un recours aux importations de produits énergétiques
Hemp to limit diffusion of difenoconazole in vegetable garden soils
No full textTriazole molecules are used to manage invasive aspergillosis, a fungal infection mainly due to Aspergillus fumigants. A. fumigants is not a phytopathogen, but, as it is widespread in soils, triazole fungicides have an unintended impact on it, selecting resistant populations' in environment. Thus, to maintain our ability to control fungal infections, whether in human health or agriculture, reduce the impact of the use of triazoles in the environment is important, notably limiting their diffusion in soils. Here we tested a hemp-based material as adsorbent to limit the spread of difenoconazole, a triazole fungicide, in vegetable soils. We studied the effects of contact time, material dose, difenoconazole concentration, and organic content of the soil using batch mode and percolation methods. Batch experiments showed that the material exhibited high adsorption capacities toward difenoconazole. Removal from the soil water increased from 46.6% using 0.35 g hemp per kg of soil to 77.0% using 1.75 g hemp per kg, for a contact time of 15 min and an initial difenoconazole concentration of 1.2 mg/L. For a contact time of 240 min, the removal was 93.5%. Percolation experiments showed that the quantity of difenoconazole removed was greater than the amount obtained by batch method: 41.9% of removal with only one passes of solution at a concentration of 12 mg/L is obtained through percolation technique whereas, with similar conditions, only 20% of removal is obtained by batch method, i.e. after 1 min of contact. The removal was strongly dependent on the number of passes: the values increased from 57.0% to 91.0% with increasing the number of passes from 1 to 15. Addition of hemp to soils allows to remove efficiently the difenoconazole fungicide from soil water. Hemp-based felt is a new and safe adsorbent that can be applied in agriculture to limit crop contamination