72 research outputs found
The food habits of three allochthonous feeding characoids in French Guiana
Une analyse des contenus stomacaux de Leporinus friderici, Myleus rhomboidalis
et M. ternetzi a été réalisée à partir d'échantillons provenant de deux
peuplements distincts de Guyane Française, prélevés aux différentes saisons
caractéristiques de cette région néotropicale : la grande saison des pluies, la
grande saison sèche et la petite saison des pluies, l'étude du régime alimentaire en
petite saison sèche ayant été volontairement omise.
M. ternetzy est un herbivore strict, qui consomme quasi-exclusivement des
feuilles prélevées sur les arbres pendant les inondations de la saison des pluies, et
des feuilles flottant à la dérive en saison sèche.
M. rhomboidalis se nourrit surtout de graines d'Euterpe oleracea en saison
sèche. Cette espèce diversifie son régime alimentaire en saison des pluies en
consommant plusieurs espèces de graines et des arthropodes.
Le régime de L. friderici présente un caractère omnivore marqué. Ce poisson
se nourrit essentiellement en saison des pluies et consomme alors des graines et des
arthropodes tombés des feuillages.
Ces résultats sont interprétés comme exprimant les préférences alimentaires
de ces espèces en saison des pluies, alors qu'en saison sèche se développent des
stratégies de survi
The growth of Myleus rhomboidalis (Cuvier, 1817) (Characiforme, Serrasalmidae) in two rivers of French Guiana
Le coumarou est un poisson d'eau douce qui semble présenter un important potentiel aquacole. La croissance de cette espèce est étudiée dans son milieu naturel dans le but d'obtenir des données de référence pour des essais d'élevage en bassins. Dans la première partie du travail nous montrons que cette espèce présente deux cycles de croissance annuels comme d'autres espèces guyanaises. Ces cycles sont synchronisés avec l'alternance des saisons. Les deux périodes de croissance active correspondent aux deux saisons des pluies de l'année et les deux ralentissements ou arrêts de croissance aux deux saisons sèches. Dans la deuxième partie du travail, la croissance de M. rhomboidalis est décrite grâce à la squelettochronologie sur la base de données non corrigée
H19 Antisense RNA Can Up-Regulate Igf2 Transcription by Activation of a Novel Promoter in Mouse Myoblasts
It was recently shown that a long non-coding RNA (lncRNA), that we named the 91H RNA (i.e. antisense H19 transcript), is overexpressed in human breast tumours and contributes in trans to the expression of the Insulin-like Growth Factor 2 (IGF2) gene on the paternal chromosome. Our preliminary experiments suggested that an H19 antisense transcript having a similar function may also be conserved in the mouse. In the present work, we further characterise the mouse 91H RNA and, using a genetic complementation approach in H19 KO myoblast cells, we show that ectopic expression of the mouse 91H RNA can up-regulate Igf2 expression in trans despite almost complete unmethylation of the Imprinting-Control Region (ICR). We then demonstrate that this activation occurs at the transcriptional level by activation of a previously unknown Igf2 promoter which displays, in mouse tissues, a preferential mesodermic expression (Pm promoter). Finally, our experiments indicate that a large excess of the H19 transcript can counteract 91H-mediated Igf2 activation. Our work contributes, in conjunction with other recent findings, to open new horizons to our understanding of Igf2 gene regulation and functions of the 91H/H19 RNAs in normal and pathological conditions
The FAIR Guiding Principles for scientific data management and stewardship
There is an urgent need to improve the infrastructure supporting the reuse of scholarly data. A diverse set of stakeholders—representing academia, industry, funding agencies, and scholarly publishers—have come together to design and jointly endorse a concise and measureable set of principles that we refer to as the FAIR Data Principles. The intent is that these may act as a guideline for those wishing to enhance the reusability of their data holdings. Distinct from peer initiatives that focus on the human scholar, the FAIR Principles put specific emphasis on enhancing the ability of machines to automatically find and use the data, in addition to supporting its reuse by individuals. This Comment is the first formal publication of the FAIR Principles, and includes the rationale behind them, and some exemplar implementations in the community
31st Annual Meeting and Associated Programs of the Society for Immunotherapy of Cancer (SITC 2016) : part two
Background
The immunological escape of tumors represents one of the main ob- stacles to the treatment of malignancies. The blockade of PD-1 or CTLA-4 receptors represented a milestone in the history of immunotherapy. However, immune checkpoint inhibitors seem to be effective in specific cohorts of patients. It has been proposed that their efficacy relies on the presence of an immunological response. Thus, we hypothesized that disruption of the PD-L1/PD-1 axis would synergize with our oncolytic vaccine platform PeptiCRAd.
Methods
We used murine B16OVA in vivo tumor models and flow cytometry analysis to investigate the immunological background.
Results
First, we found that high-burden B16OVA tumors were refractory to combination immunotherapy. However, with a more aggressive schedule, tumors with a lower burden were more susceptible to the combination of PeptiCRAd and PD-L1 blockade. The therapy signifi- cantly increased the median survival of mice (Fig. 7). Interestingly, the reduced growth of contralaterally injected B16F10 cells sug- gested the presence of a long lasting immunological memory also against non-targeted antigens. Concerning the functional state of tumor infiltrating lymphocytes (TILs), we found that all the immune therapies would enhance the percentage of activated (PD-1pos TIM- 3neg) T lymphocytes and reduce the amount of exhausted (PD-1pos TIM-3pos) cells compared to placebo. As expected, we found that PeptiCRAd monotherapy could increase the number of antigen spe- cific CD8+ T cells compared to other treatments. However, only the combination with PD-L1 blockade could significantly increase the ra- tio between activated and exhausted pentamer positive cells (p= 0.0058), suggesting that by disrupting the PD-1/PD-L1 axis we could decrease the amount of dysfunctional antigen specific T cells. We ob- served that the anatomical location deeply influenced the state of CD4+ and CD8+ T lymphocytes. In fact, TIM-3 expression was in- creased by 2 fold on TILs compared to splenic and lymphoid T cells. In the CD8+ compartment, the expression of PD-1 on the surface seemed to be restricted to the tumor micro-environment, while CD4 + T cells had a high expression of PD-1 also in lymphoid organs. Interestingly, we found that the levels of PD-1 were significantly higher on CD8+ T cells than on CD4+ T cells into the tumor micro- environment (p < 0.0001).
Conclusions
In conclusion, we demonstrated that the efficacy of immune check- point inhibitors might be strongly enhanced by their combination with cancer vaccines. PeptiCRAd was able to increase the number of antigen-specific T cells and PD-L1 blockade prevented their exhaus- tion, resulting in long-lasting immunological memory and increased median survival
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