Éditeur(s) : HAL CCSD Ecological Society of America
Résumé : Herbivores are often implicated in the generation of the extraordinarily diverse tropical flora. One hypothesis linking enemies to plant diversification posits that the evolution of novel defenses allows plants to escape their enemies and expand their ranges. When range expansion involves entering a new habitat type, this could accelerate defense evolution if habitats contain different assemblages of herbivores and/or divergent resource availabilities that affect plant defense allocation. We evaluated this hypothesis by investigating two sister habitat specialist ecotypes of Protium subserratum (Burseraceae), a common Amazonian tree that occurs in white-sand and terra firme forests. We collected insect herbivores feeding on the plants, assessed whether growth differences between habitats were genetically based using a reciprocal transplant experiment, and sampled multiple populations of both lineages for defense chemistry. Protium subserratum plants were attacked mainly by chrysomelid beetles and cicadellid hemipterans. Assemblages of insect herbivores were dissimilar between populations of ecotypes from different habitats, as well as from the same habitat 100 km distant. Populations from terra firme habitats grew significantly faster than white-sand populations; they were taller, produced more leaf area, and had more chlorophyll. White-sand populations expressed more dry mass of secondary compounds and accumulated more flavone glycosides and oxidized terpenes, whereas terra firme populations produced a coumaroylquinic acid that was absent from white-sand populations. We interpret these results as strong evidence that herbivores and resource availability select for divergent types and amounts of defense investment in white-sand and terra firme lineages of Protium subserratum, which may contribute to habitat-mediated speciation in these trees.
ISSN: 0012-9658

hal-01032403
https://hal.archives-ouvertes.fr/hal-01032403
DOI : 10.1890/12-1920.1

Résumé : Tahiti’s pearl farming industry plays a major socio-economic role in French Polynesia. In an increasingly competitive market where the production of high quality pearls becomes essential, research can help secure and ensure sustainable production. In that context, Ifremer, in close collaboration with the “direction des resources marines” (French Polynesian government agency) has developed research projects on the “sustainable development of pearl farming”. This program is organized along 3 axes: (1) understanding the animal physiology and initiating a genetically selective breeding program of donor oysters; (2) understanding pearl oyster larvae dispersal and recruitment; (3) understanding the molecular mechanisms underlying biomineralization processes during shell and pearl formation. It is in this frame that we have developed a highthroughput Expressed Sequence Tags pyrosequencing program on the calcifying mantle, combined with proteomic analyses of the shell and pearl. We analyzed 276738 EST sequences, leading to the constitution of a P. margaritifera mantle transcripts catalogue of 82 sequences potentially involved in biomineralization. Our results provided direct evidence that our ESTs data set covers a large number of the matrix proteins of P. margaritifera. In addition, our proteomic analysis enabled us to retrieve, in silico, all the sequences from P. margaritifera involved in the biomineralization process already published on databases. Integration of these two methods allowed, for the first time, the global composition of calcifying tissue and calcified structures to be examined in tandem.
Recent Advances in Pearl Research—Proceedings of the International Symposium on Pearl Research 2011.Edited by Shugo Watabe, Kaoru Maeyama and Hiromichi Nagasawa. 2013. ISBN : 978-4-88704-158-5. pp.184-194

Droits : 2013 TERRAPUB. All rights reserved.
http://archimer.ifremer.fr/doc/00167/27840/26049.pdf
http://archimer.ifremer.fr/doc/00167/27840/

Résumé : En raison de sa richesse en ressources génétiques, et des utilisations traditionnelles locales qui en sont faites, la biodiversité végétale issue du bassin amazonien constitue une véritable source de principes actifs à valoriser. L’espèce Euterpe oleracea Mart., vernaculairement appelée baie d’açai, qui connaît un intérêt scientifique important, est le parfait exemple de ressources naturelles bioactives valorisées issues de cette zone géographique. Les études scientifiques lui confèrent de très nombreuses propriétés biologiques, mais, la plus connue et la plus médiatisée est sa capacité antioxydante liée majoritairement à sa composition polyphénolique. En Guyane française, on peut parler de « diversité » au sein de la famille des Palmiers puisque plus de 75 espèces y ont été recensées. Parmi lesquelles, on peut citer une espèce très commune ayant des propriétés surtout alimentaires, et dont la connaissance phytochimique reste, à l’heure actuelle, très limitée : l’Oenocarpus bataua Mart dit patawa. Ce sujet de thèse de doctorat s’articule autour de la mesure de l’activité antioxydante du fruit mûr de ce palmier, et de la détermination des polyphénols responsables de cette dernière. La singularité de ce travail réside dans l’étude des différentes composantes tissulaires du fruit : mésocarpe, épicarpe et mélange épicarpe/mésocarpe (MEM). Dans un premier temps, les conditions les plus favorables d’extraction de biomolécules (notamment de l’épicarpe et du mésocarpe) ont été définies à l’aide du test DPPH. Les tests préliminaires effectués sur les tissus pris séparément, ont conduit à sélectionner un mélange acétone/eau (70/30, v/v) pour révéler, au mieux, la capacité antioxydante de chaque partie du fruit. Une étape de délipidation initiale s’est avérée nécessaire dans le cas de l’étude du mésocarpe. La confirmation de l’activité antioxydante a été réalisée au moyen d’autres tests d’activité chimique (TEAC, FRAP, ORAC), et a été complétée par l’utilisation d’un test d’activité biologique (KRL) en raison de ses mécanismes réactionnels plus complets. Il en ressort que le tissu végétal le plus antioxydant est le mésocarpe qui contient des proanthocyanidines, famille de composés phénoliques connue pour ses nombreuses activités biologiques.Le même travail a été effectué sur les tissus regroupés (fruit global ou MEM). Ainsi, a été retenue l’utilisation du solvant mixte acétone/eau sans étape de délipidation initiale. La capacité antioxydante du fruit étudié a été comparée à celle de l’açai, espèce choisie comme référence. Il s’avère que les extraits d’açai ont une activité antioxydante très supérieure à celle du patawa lorsqu’ils sont testés vis-à-vis de l’ORAC et du KRL. Le tissu mésocarpe a, lui, démontré une capacité antioxydante supérieure à celle de l’açai. Ces résultats sont à associer avec la composition phytochimique propre à chaque fruit. La composition polyphénolique du fruit de patawa, déterminée par UPLC/MSn, supposerait la présence d’anthocyanes, de tanins condensés, de stilbènes et d’acides phénoliques. Ces travaux, qui méritent d’être approfondis, en particulier pour le mésocarpe, ouvrent de nouvelles perspectives d’utilisation du fruit patawa, en particulier l’incorporation de composés phénoliques issus du mésocarpe dans des formulations galéniques ayant attrait aux domaines de la Nutrition, de la Cosmétique et de la Pharmaceutique.
Due to its wealth in genetic resources, and to traditional uses, plant biodiversity issued from the Amazonian Basin is a real source of active process to valorize. The specie Euterpeoleracea Mart., usually called acai berry, which is experiencing a huge scientific interest, is the perfect example of valued natural bioactive resources from the geographic area. Scientific studies give it many biological properties, but the most known is its antioxidant property mainly due to its polyphenolic composition. In French Guiana, we can use the term “diversity” within the palm family with more than 75 species identified. Among them is a common species, Oenocarpus bataua Mart., called “Patawa”, mainly with alimentary properties but for which knowledge of phytochemical properties is until now very poor. The present research deals with determining the antioxidant activity of this palm fruit and with the identification of the polyphenols responsible for it.The uniqueness of this work lays in the study of the different tissue components of this fruit namely the mesocarp, the epicarp and mixing epicarp / mesocarp (MEM). In a first time, the most favorable extraction conditions of biomolecules (particularly of the epicarp and mesocarp) were defined using the DPPH test. The preliminary tests performed on those tissues taken separately, have led to select an acetone / water (70/30, v / v) to reveal, at best, the antioxidant capacity of each part of the fruit. An initial defatting step was necessary in the case of the study of the mesocarp. The confirmation of the antioxidant activity was carried out by other tests of chemical activity (TEAC, FRAP, ORAC), and was supplemented by the use of a bioassay (KRL) due to its more complete reaction mechanisms. Results point out that the most antioxidant tissue is the mesocarp that contains proanthocyanidins, phenolics of a chemical family known for its numerous biological activities.The same work was performed on tissues combined (overall result). The mixed solvent acetone / water, without initial defatting step, has been selected. The antioxidant capacity of fruit was compared to that of the Acai specie chosen as a reference. It turns out that acai extracts have antioxidant activity much greater than that of Patawa when tested vis-à-vis of ORAC and KRL. In contrary, mesocarp tissue has a greater antioxidant capacity than that of Acai. These results can be associated with the phytochemical composition of each fruit. The polyphenolic composition of the fruit of Patawa determined by UPLC / MSn, reflects the presence of anthocyanins, condensed tannins, stilbene and phenolic acids. This work, which deserves to be deepened, especially for the mesocarp tissue, opens new prospects for the use of Patawa fruit, especially the incorporation of phenolic compounds from the mesocarp in pharmaceutical formulations linked to the fields of Nutrition, of Cosmetics and Pharmaceuticals.

http://www.theses.fr/2012AGUY0573/document

Éditeur(s) : HAL CCSD CSIRO Publishing
Résumé : International audience
The present study assessed the occurrence of multiple paternity in four litters of bull shark Carcharhinus leucas (n¼5, 8, 9 and 11 embryos) sampled at Reunion Island in the Western Indian Ocean. Using 21 microsatellite loci, we revealed that two litters were generated from two sires each, demonstrating for the first time multiple paternity for this species. We also reported a high paternal skew (10 : 1 in Litter 1 and 7 : 1 in Litter 3), which may be because of postcopulatory or post-zygotic selection processes. These results contribute to a better understanding of the reproductive behaviour of the bull shark, which remains poorly documented. The present study must be expanded to assess the frequency of multiple paternity in this species, and to test for genetic or cryptic benefits (convenience polyandry), which is important for long-term conservation and management plans.
ISSN: 1323-1650

hal-01253775
https://hal.archives-ouvertes.fr/hal-01253775
https://hal.archives-ouvertes.fr/hal-01253775/document
https://hal.archives-ouvertes.fr/hal-01253775/file/Pirog%20et%20al.%20-%202015%20-%20First%20evidence%20of%20multiple%20paternity%20in%20the%20bull%20s_hal.pdf
DOI : 10.1071/mf15255

Résumé : Face aux difficultés d’identification des arbres de la famille des Lauracées et dans un but d’établissement d’une production durable et certifiée d’huiles essentielles, l’entreprise KLR a voulu mettre en place un nouvel outil d’identification multi-critères qui consiste à croiser plusieurs types de caractères afin d’obtenir une détermination taxonomique fiable.Trois méthodes d’identification ont été utilisées : la chimie (analyse de l’odeur de l’écorce), le code barre génétique et l’anatomie du bois. Une analyse par positionnement multidimensionnel non-métrique a permis de faire un tri des critères anatomiques du bois pertinents dans l’identification des Lauracées étudiées, au final 14 critères ont été retenus. D’après les données anatomiques dont nous disposons, nous proposons une clé de détermination au genre. En génétique, la technique de code barres de la région chloroplastique intergénique trnH-psbA a été appliquée aux individus récoltés. En comparant les séquences de tous les individus, 40% des individus peuvent être identifiés au genre car ils présentent des haplotypes uniques. Des haplotypes au sein des genres ont été déterminés et permettent d’identifier l’espèce pour 40 à 100 % des individus selon le genre. L’analyse SPME de l’odeur des écorces a permis de définir pour chaque espèce une carte d’identité chimique à partir des molécules majoritaires. Des chémotypes ont été définis au sein des espèces Licaria cannella, Ocotea indirectinervia et Sextonia rubra. Ces trois domaines d’observation ont permis de constituer une base de type Xper2 pour l’identification.Un criblage des essences intéressantes de par leur rendement en huile essentielle a été effectué. En ce qui concerne la partie extraction de l’huile essentielle, trois espèces montrent un rendement en huile essentielle de l’écorce supérieur à 0,3% et 5 espèces montrent un rendement en huile essentielle du bois supérieur à 0,3%. Les évaluations olfactives menées par un expert ont permis de séparer les huiles distillées en 5 différentes notes. Nous avons jugé intéressant de savoir si l’outil d’identification multicritère pouvait prédire les compositions et rendements en huile essentielle de l’espèce identifiée avant l’abattage de l’arbre. Des études complémentaires ont donc été menées. Pour plus de la moitié des arbres, la signature de l’écorce, la composition de l’huile essentielle de l’écorce et la composition de l’huile essentielle du bois sont similaires. La tentative d’établir un lien entre les caractéristiques des cellules à huile et le rendement s’est avérée infructueuse.
In order to develop a sustainable production of certified essential oils extracts, the compangy KLR has struggled with the identification of the trees from the family of Lauraceae. This is the main reason that led to the project of creating an identification tool for this family.This tool would be based on three approaches: chemistry (chemical signature of the dark), wood anatomy and genetic barcoding. By means of a non-metric multidimensional scaling analysis, we selected a list of 14 relevant wood anatomical features that can identify the trees to the genera. For the genetics, the barcoding of trnH-psbA an intergenic region of the DNA has been used. When comparing all the sequences from all the individuals, 40% of the individuals can be identified to the genera because of their specific haplotype. Haplotypes within the genera have also been established. Chemical identity cards have been set with the SPME analysis technique and chemotypes have been defined inside the species Licaria cannella, Ocotea indirectinervia and Sextonia rubra. These three identification approaches allowed us to construct an identification tool on Xper².During the study, we aimed to screen what species would be interesting for its essential oil yield. Three species showed an essential oil bark yield above 0.3%. five species showed an essential oil wood yield above 0.3%. An expert held an olfactory evaluation on the oils and divided the essential oils in five olfactory groups. We found it relevant to improve the identification tool by trying to predict the compositions of the oils before the three was cut down. In the case of the half of trees studied by SPME analyses, the composition of the wood and the bark essential oils were similar. On the other hand, no link was found between the oil cells dimensions and the essential oil yield.

http://www.theses.fr/2012AGUY0516/document

Éditeur(s) : HAL CCSD Nakanishi Printing Co
Résumé : International audience
In Vibrio cholerae, the etiological agent of cholera, most of the virulence genes are located in two pathogenicity islands, named TCP (Toxin-Co-regulated Pilus) and CTX (Cholera ToXins). For each V. cholerae pathogenicity gene, we retrieved every primer published since 1990 and every known allele in order to perform a complete in silico survey and assess the quality of the PCR primers used for amplification of these genes. Primers with a melting temperature in the range 55-60 degrees C against any target sequence were considered valid. Our survey clearly revealed that two thirds of the published primers are not able to properly detect every genetic variant of the target genes. Moreover, the quality of primers did not improve with time. Their lifetime, i.e. the number of times they were cited in the literature, is also not a factor allowing the selection of valid primers. We were able to improve some primers or design new primers for the few cases where no valid primer was found. In conclusion, many published primers should be avoided or improved for use in molecular detection tests, in order to improve and perfect specificity and coverage. This study suggests that bioinformatic analyses are important to validate the choice of primers.
ISSN: 1342-6311

hal-01546178
https://hal.archives-ouvertes.fr/hal-01546178
DOI : 10.1264/jsme2.ME11317

Éditeur(s) : HAL CCSD
Résumé : International audience
Introduction: Type 1 diabetes mellitus, a T cell-mediated autoimmune disease, is a complex process that results from the loss of tolerance to insulin and other beta-cell-specific antigens. Diabetes is associated with an increased risk of death from infectious disease. Hyperglycaemia, oxidative stress and inflammation have been identified as the main factor contributing to the development of diseases associated with diabetes mellitus. However, experimental evidence indicates individual susceptibility to develop complications of diabetes. Various genetic and environmental factors have been studied so far, but precise causation has yet to be established. Numerous studies in rodents and human subjects have been performed in order to elucidate the role of B and T cells, which determine the risk of development and progression of diabetes. Moreover, the therapy management of diabetes includes nutritional recommendations and exercise training. The effects of exercise training on glycemia, oxidative stress, inflammation and immune response are well known and favorable to limit the development of diabetes and its complications. More interestingly, ?-galacto-oligosaccharides (?-GOS) are prebiotics that selectively alter the composition of gut microbiota and exhibit strong antioxidant, anti- inflammatory and insulin-sensitive effects in vitro (Efstathiou and Fathi 2010) and in vivo (Boucher J et al. 2003). Thus, ? -GOS is a potential functional food for the treatment of diabetes. But, less is known about the effect of training and ? –GOS on immune response in diabetes. In this context, the aim of this work was to study the immune response in a streptozotocin-induced type 1 diabetes with two therapeutic means: training and ?-galacto-oligosaccharides (?-GOS) alone or combined. Methods: Forty-two male Wistar rats were divided into control placebo, streptozotocin-diabetic rat (STZ) groups supplemented or not with ?-GOS (20 mg/kg/day) for 8 weeks and/or following endurance training. The training program was individualized and consisted in a 1h/day, 5days/week running during 8 weeks on a motor-driven treadmill. At the end of the protocol, blood was obtained by venous puncture into heparin-containing tubes for further analyses (glucose, insulin, fructosamine and immune responses) Results: Relative to the control group, STZ rats exhibited hyperglycemia, insulin deficiency and a trend to higher plasma fructosamine levels, a marker of glycated proteins. They also exhibited a decrease in T and B cells and an increase in natural killers (NK). ?-GOS treatment reduced plasma fructosamine levels and increased B cells compared to STZ rats. Training induced a decrease in plasma glucose, T cells and an increase in B cells in STZ rats. The combined effect of ?-GOS and training didn’t potentiate the immune response on B and T cells but inhibited the effects of training on NK. Discussion: Our results suggest that training and ?-GOS alter positively plasma glucose and/or fructosamine and the immune response. But the effects of combined treatments only concern limited parameters. ? -GOS effects could be partly attributable to its immunomodulating activity. Keywords: ?-GOS, training, immune cells, diabetes. References Efstathiou, T. and D. Fathi. Sojasun Technologies. 2010 Boucher J et al. J Physiol Biochem. 59(3):169-73, 2003
18th Annual Congress of the European College of Sport Sciences, Barcelone, Spain, 26-29 juin.
Barcelone, Spain

hal-01159378
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01159378