Knot-isomers of Moebius Cyclacene: How Does the Number of Knots Influence the Structure and First Hyperpolarizability?

Four large ring molecules composed by 15 nitrogen-substituted benzene rings, named as "knot-isomers of Moebius cyclacene", i.e. non-Moebius cyclacenes without a knot (0), Moebius cyclacenes with a knot (1), non-Moebius cyclacenes with two knots (2), and Moebius cyclacenes with three knots (3), are systematically studied for their structures and nonlinear optical properties. The first hyperpolarizability (beta_0) values of these four knot-isomers structures are 4693 (0) < 10484 (2) < 25419 (3) < 60846 au (1). The beta_0 values (60846 for 1, 10484 for 2 and 25419 au for 3) of the knot-isomers with knot(s) are larger than that (4693 au for 0) of the knot-isomer without a knot. It shows that the beta_0 value can be dramatically increases (13 times) by introducing the knot(s) to the cyclacenes structures. It is found that introducing knots to cyclacenes is a new means to enhance the first hyperpolarizability.Comment: 12 pages, 4 figure

Unique epigenetic signature in T cell compartment after epicutaneous immunotherapy in peanut sensitized mice

International audienceRationale Epicutaneous immunotherapy (EPIT) induces naïve Tregs, which play a crucial role in the bystander effect identified in a model of food allergic mice. Previously, EPIT was shown to alter epigenetic modifications and expression of Th2 and Tregs without influencing the expression of Th1 in peanut-sensitized mice. This study investigates methylation modifications occurring in specific T cell compartments. Methods Mice were orally sensitized to peanut and then treated with EPIT or non-treated. Mice were sacrificed at the end of treatment or 8 weeks after the end of immunotherapy. Regulatory T cells (CD62L+Foxp3+ and CD62L-Foxp3+) were sorted directly from the spleen and Th2 and Th1 cells were purified after a short in vitro reactivation of splenocytes. DNA methylation at Gata3 promoter and Foxp3 CNS2 was analysed in all sorted cells by pyrosequencing. Results Epicutaneous immunotherapy did not modify proportions of Th1 and Th2 cells in the spleen. The hypermethylation of CpG islands of Gata3 only occurred in Th2 cells for EPIT-treated mice at the end of immunotherapy and was sustained 8 weeks later (p<0.05 vs Sham). In parallel, significant hypomethylation was observed in the Foxp3 CpG islands of naïve Tregs only (p<0.05), not effector Tregs, at the end of EPIT, and persisted for 8 weeks following the end of treatment (p<0.001). Conclusions The unique epigenetic signature of EPIT is confirmed at cellular level for Gata3 (Th2) and Foxp3 (naïve Tregs), suggesting the induction of tolerance and prevention of further sensitization. Foxp3 hypomethylation occurring only on naïve Tregs underlines the crucial role of EPIT-induced naïve Tregs