L1 retrotransposition in the soma: a field jumping ahead

Retrotransposons are transposable elements (TEs) capable of "jumping" in germ, embryonic and tumor cells and, as is now clearly established, in the neuronal lineage. Mosaic TE insertions form part of a broader landscape of somatic genome variation and hold significant potential to generate phenotypic diversity, in the brain and elsewhere. At present, the LINE-1 (L1) retrotransposon family appears to be the most active autonomous TE in most mammals, based on experimental data obtained from disease-causing L1 mutations, engineered L1 reporter systems tested in cultured cells and transgenic rodents, and single-cell genomic analyses. However, the biological consequences of almost all somatic L1 insertions identified thus far remain unknown. In this review, we briefly summarize the current state-of-the-art in the field, including estimates of L1 retrotransposition rate in neurons. We bring forward the hypothesis that an extensive subset of retrotransposition-competent L1s may be de-repressed and mobile in the soma but largely inactive in the germline. We discuss recent reports of non-canonical L1-associated sequence variants in the brain and propose that the elevated L1 DNA content reported in several neurological disorders may predominantly comprise accumulated, unintegrated L1 nucleic acids, rather than somatic L1 insertions. Finally, we consider the main objectives and obstacles going forward in elucidating the biological impact of somatic retrotransposition

Recherche des résidus d’antibiotiques dans les viandes

Une méthode simple, sensible, rapide et peu onéreuse de dépistage est décrite pour la recherche des antibiotiques dans les viandes. Basée sur la techni que des zones d’inhibition des cultures microbiennes, l’originalité de la méthode résulte de la technique d’obtention d'un exsudât musculaire stérile, de l’emploi de deux espèces microbiennes Bacillus subtilis cultivant sur gélose à pH 6ft et 8,0 et de Sarcina lu tea cultivant sur gélose à pH 7,0

Dépistage, au moyen de l'examen testiculaire, des volailles castrées par administration per os d’œstrogènes de synthèse.

Pantaléon Jean, Billon Jean, Morre Jean. Dépistage, au moyen de l’examen testiculaire des volailles castrées par administration per os d’œstrogènes de synthèse. In: Bulletin de l'Académie Vétérinaire de France tome 118 n°2, 1965. pp. 71-82

Lésions de la « maladie du carré » chez le porc

Billon Jean, Tassin P. Lésions de la «Maladie du carré» chez le porc. In: Bulletin de l'Académie Vétérinaire de France tome 128 n°8, 1975. pp. 389-394

Comparison of phosphor screen autoradiography and micro-pattern gas detector based autoradiography for the porosity of altered rocks

This study aims to further develop the C-14-PMMA porosity calculation method with a novel autoradiography technique, the Micro-pattern gas detector autoradiography (MPGDA). In this study, the MPGDA is compared with phosphor screen autoradiography (SPA). A set of rock samples from Martinique Island exhibiting a large range of connected porosities was used to validate the MPGDA method. Calculated porosities were found to be in agreement with ones from the SPA and the triple-weight method (TW). The filmless nature of MPGDA as well as straightforward determination of C-14 radioactivity from the source rock makes the porosity calculation less uncertain. The real-time visualization of radioactivity from C-14 beta emissions by MPGDA is a noticeable improvement in comparison to SPA.Peer reviewe