Chimistes alsaciens à Paris au 19ème siècle: un réseau,une école?

Au 19ème siècle, on remarque la présence, dans la chimie française, d'un nombre considérable d'Alsaciens dont les contributions scientifiques ne peuvent être ignorées. Essentiellement à la suite de la guerre franco-prussienne, leur origine régionale est souvent mise en avant afin de leur attribuer une certaine singularité: mais peut-on distinguer les Alsaciens des autres chimistes français avant 1870? Forment-ils un groupe homogène de par la spécificité de leur lieu d'origine? Cet article a pour but de démontrer que, par leurs options théoriques, leurs relations personnelles et professionnelles et aussi par leur participation à bien d'initiatives communes, ils se sont organisés au sein de la communauté scientifique parisienne. Parmi ces formes d'organisation, on dégage le rôle fondamentale de l'école de recherche du chimiste Adolphe Wurtz (1817–84) qui apu fonctionner comme noyau de ce qu'on peut considérer comme un vrai réseau de chimistes alsaciens à Paris, pendant la seconde moitié du 19ème siècle.     

Mutations in genes encoding subunits of RNA polymerases I and III cause Treacher Collins syndrome

We identified a deletion of a gene encoding a subunit of RNA polymerases I and III, POLR1D, in an individual with Treacher Collins syndrome (TCS). Subsequently, we detected 20 additional heterozygous mutations of POLR1D in 252 individuals with TCS. Furthermore, we discovered mutations in both alleles of POLR1C in three individuals with TCS. These findings identify two additional genes involved in TCS, confirm the genetic heterogeneity of TCS and support the hypothesis that TCS is a ribosomopathy.     

Role of AGC kinases in plant growth and stress responses

AGC kinases are important regulators of cell growth, metabolism, division, and survival in mammalian systems. Mutation or deregulation of members of this family of protein kinases contribute to the pathogenesis of many human diseases, including cancer and diabetes. Although AGC kinases are conserved in the plant kingdom, little is known about their molecular functions and targets. Some of the best-studied plant AGC kinases mediate auxin signaling and are thereby involved in the regulation of growth and morphogenesis. Furthermore, certain members are regulated by lipid-derived signals via the 3-phosphoinositide-dependent kinase 1 (PDK1) and the kinase target of rapamycin (TOR), similar to its animal counterparts. In this review, we discuss recent findings on plant AGC kinases that unravel important roles in the regulation of plant growth, immunity and cell death, and connections to stress-induced mitogen-activated protein kinase signaling cascades.     

Tegmina-size variation in a Neotropical cricket with implications on spectral song properties

This study evaluates the relationship between shape and size of tegmen, harp, mirror, and spectral range of calling song frequency of a Neotropical cricket subpopulation (Lerneca inalata beripocone. In addition, we compare intraspecific morphological divergence and calling song properties between individuals from different sites of the Pantanal of Poconé, Mato Grosso, Brazil. Regression analysis showed that the dominant and maximum calling song frequencies were negatively correlated with tegmen size, i.e. frequencies are either lower or higher depending on the corresponding size variation in resonance structures of the forewings. Canonical variable analysis demonstrated marked intraspecific differences in morphometric characters between localities of a L. inalata subpopulation c. 35 km apart (SESC-Pantanal Advanced Research Base and Pouso Alegre Farm, Mato Grosso, Brazil). Lerneca inalata beripocone at SESC had larger forewings than conspecifics from Pouso Alegre Farm. These morphological variations of wing properties related to reproductive behaviours were interpreted as fitness parameters, likely shaped by restricted gene flow during temporal habitat isolation episodes. Such isolation patterns occur in the Pantanal wetlands for several months during the annual hydrological cycle.     

Microdeletion encompassing MAPT at chromosome 17q21.3 is associated with developmental delay and learning disability

Recently, the application of array-based comparative genomic hybridization (array CGH) has improved rates of detection of chromosomal imbalances in individuals with mental retardation and dysmorphic features. Here, we describe three individuals with learning disability and a heterozygous deletion at chromosome 17q21.3, detected in each case by array CGH. FISH analysis demonstrated that the deletions occurred as de novo events in each individual and were between 500 kb and 650 kb in size. A recently described 900-kb inversion that suppresses recombination between ancestral H1 and H2 haplotypes encompasses the deletion. We show that, in each trio, the parent of origin of the deleted chromosome 17 carries at least one H2 chromosome. This region of 17q21.3 shows complex genomic architecture with well-described low-copy repeats (LCRs). The orientation of LCRs flanking the deleted segment in inversion heterozygotes is likely to facilitate the generation of this microdeletion by means of non-allelic homologous recombination.